Kidneys, bladder and reproduction

1Why it matters

The urinary system makes urine and carries it out of the body. The reproductive system makes the sex cells and sex hormones and, in females, carries and feeds a pregnancy. They share a crowded space in the pelvis, and in males one tube, the urethraurethrayoo-REE-thruhThe tube that carries urine from the bladder out of the body.Full entry Close, carries both urine and semen, so surgical texts often teach the male reproductive organs with the urinary system.

You meet these organs in urology, gynecologygynecologygy-nuh-KOL-uh-jeeThe branch of medicine that cares for the female reproductive organs and breasts.gynec/o woman-logy study ofFull entry Close and obstetrics cases, and in some general surgery cases, such as a groin herniaherniaHER-nee-uhA bulge of an organ or tissue through a weak spot in the muscle or tissue wall that normally holds it in.Full entry Close repair.

• The kidneys guard the whole body. They clean the blood, set its water, salt and acid levels, help control blood pressure and clear many drugs. When they fail, drugs can build up, so doses change.
• Urine output is a window on the patient. The team measures urine during surgery to judge fluid balance; a normal adult makes about 0.5 to 1 mL of urine per kilogram of body weight per hour. Chapter 31 teaches urinary catheters and measuring urine.
• Pelvic organs lie close together. The bladder sits just in front of the uterus, and each ureterureterYOOR-uh-terOne of the two tubes that carry urine from the kidneys down to the bladder.Full entry Close passes under a uterine artery beside the cervix, so in pelvic surgery the surgeon finds them before anything is clamped.
• Scopes go in through the urethra. Through it the urologist reaches the bladder, the prostateprostatePROS-taytA walnut-sized gland below the bladder in males that surrounds the urethra and makes part of the fluid in semen.Full entry Close, the ureters and the inside of the kidney.

This chapter teaches the structure and work of both systems and where surgery meets them. Other chapters hold the rest: the renal arteries and veins as part of the circulation in chapter 5; the adrenal glandsadrenal glanduh-DREE-nul GLANDOne of two small glands that sit on top of the kidneys and make hormones such as cortisol, aldosterone and epinephrine.ad- toward, nearren/o kidney-al relating toFull entry Close, and the hormones of the pituitary, ovaries and testes as endocrine glandsendocrine glandEN-doh-krin GLANDA gland that releases hormones straight into the blood instead of through a tube or duct.endo- within-crine to secreteFull entry Close, in chapter 9; urinary tract infections in chapter 10; how tumors and disease develop in chapter 11; diureticsdiureticdy-yoo-RET-ikA drug that makes the kidneys pass more water and salt out of the body as urine.dia- throughur/o urine-etic relating toFull entry Close in chapter 12; urinary catheters, measuring urine and the lithotomylithotomylih-THOT-uh-meeA position lying on the back with the hips and knees bent and the legs raised and spread apart, often in stirrups.lith/o stone-tomy cutting intoFull entry Close position in chapter 31; hernia repair and breast surgery in chapter 32; the obstetric and gynecologic operations in chapter 33; the genitourinarygenitourinaryjen-ih-toh-YOOR-ih-nair-eeRelating to the genital (reproductive) organs and the urinary organs together.genit/o reproductive organsurin/o urine-ary relating toFull entry Close operations, with diseases such as kidney stoneskidney stoneKID-nee STOHNA hard, pebble-like lump of minerals that forms inside the kidney.Full entry Close and an enlarged prostate, in chapter 34; and breast reconstruction in chapter 38.

2The urinary system at a glance

The urinary system has four kinds of organs.

• Two kidneys filter the blood and make urine.
• Two uretersureterYOOR-uh-terOne of the two tubes that carry urine from the kidneys down to the bladder.Full entry Close carry urine from the kidneys to the bladder.
• The bladder stores urine until it is a good time to empty it.
• The urethraurethrayoo-REE-thruhThe tube that carries urine from the bladder out of the body.Full entry Close carries urine from the bladder out of the body.

What the kidneys do

Urine is the by-product. The kidney's real work is keeping the makeup of the blood steady, and it does several jobs at once.

1. Filters out wastes: it removes the waste products of the body's chemistry, such as ureaureayoo-REE-uhA waste product the liver makes when it breaks down protein, which the kidneys remove in urine.ur/o urineFull entry Close, and excess water, and sends them out in the urine.
2. Balances fluid and electrolytes: it adjusts how much water and how much sodium, potassium and other salts it keeps, which holds the blood's volume steady. This is homeostasishomeostasishoh-mee-oh-STAY-sisThe body's way of keeping its inside conditions, such as temperature, fluids and blood sugar, steady.home/o same-stasis standing still, staying the sameFull entry Close of fluid volumefluid volumeFLOO-id VOL-yoomThe amount of fluid in the body, or in one of its spaces such as the blood vessels.Full entry Close.
3. Helps control blood pressure: it releases the enzymeenzymeEN-zimeA protein that speeds up a chemical reaction in the body without being used up.Full entry Close renin, which starts a chain that raises blood pressure (see below).
4. Activates vitamin D and helps control calcium: it makes calcitriolcalcitriolkal-sih-TRY-olThe active form of vitamin D, given as a drug to raise calcium absorption or, as an ointment, for psoriasis.Full entry Close, the active form of vitamin D, which lets the gut absorbabsorptionub-ZORP-shunThe taking in of a substance, such as a drug or a nutrient, into the bloodstream.Full entry Close calcium.
5. Drives red blood cell production: it makes most of the body's erythropoietinerythropoietinih-rith-roh-POY-uh-tinA hormone made mainly by the kidneys that tells the bone marrow to make red blood cells.erythr/o red-poietin substance that makesFull entry Close (EPO), the hormone that tells the bone marrowbone marrowbone MAIR-ohThe soft, spongy tissue inside bones that makes blood cells.Full entry Close to make red cells.
6. Keeps the blood's pH in range: it can get rid of extra acid or extra base.
7. Clears drugs: many water-soluble drugs leave the body in the urine.

When the kidneys fail, every one of these jobs suffers. The patient may have weakness, shortness of breath, widespread swelling (edema), anemiaanemiauh-NEE-mee-uhA lower than normal number of red blood cells or amount of hemoglobin in the blood.a- without, lacking-emia blood conditionFull entry Close, too much acid and potassium in the blood, and heart rhythm problems.

3The kidneys

Where they sit

The kidneys are two bean-shaped organs, each about the size of a fist: about 11 to 14 cm long, 6 cm wide and 4 cm thick.

• They lie against the back wall of the abdomen, one on each side of the spine, in the retroperitoneal space, behind the peritoneumperitoneumpair-ih-toh-NEE-umThe thin membrane that lines the belly cavity and covers most of the organs inside it.peri- aroundton stretched-eum a structureFull entry Close.
• They reach from about the 12th thoracicthoracicthuh-RAS-ikRelating to the chest, or to the middle part of the spine.thorac/o chest-ic relating toFull entry Close to the 3rd lumbarlumbarLUM-barHaving to do with the lower back, the part of the spine between the ribs and the pelvis.Full entry Close vertebra (T12 to L3). The right kidney sits a little lower than the left, because the liver lies above it.
• The 11th and 12th ribs shield their upper parts.
• An adrenal glandadrenal glanduh-DREE-nul GLANDOne of two small glands that sit on top of the kidneys and make hormones such as cortisol, aldosterone and epinephrine.ad- toward, nearren/o kidney-al relating toFull entry Close sits on top of each one; chapter 9 teaches these glands.

The kidneys get a large share of the blood: about a fifth to a quarter of everything the heart pumps at rest.

Three layers wrap and hold each kidney.

1. The renal capsule, a tough fibrousfibrousFY-brusMade of or containing tough threads (fibers), especially of connective tissue.fibr/o fiber-ous full of, relating toFull entry Close layer, covers the kidney itself and helps hold its shape.
2. A cushion of fat, the renal fat pad, surrounds the capsule and absorbsabsorptionub-ZORP-shunThe taking in of a substance, such as a drug or a nutrient, into the bloodstream.Full entry Close shocksshockshokA life-threatening state in which blood flow is too low to bring enough oxygen to the body's tissues.Full entry Close.
3. The renal fasciafasciaFASH-ee-uhA sheet or band of tough connective tissue that covers and separates muscles and organs.fasci/o bandFull entry Close encloses the fat and the kidney and anchors them to the back wall. It is also called Gerota fascia.

Because the kidneys lie behind the peritoneum, the surgeon can reach them from the flank or through the abdomen. Today a simple nephrectomy, the removal of one kidney, is done through the abdomen with the patient in a modified lateral position, most often by laparoscopylaparoscopylap-uh-ROS-kuh-peeSurgery or an exam done through small cuts in the belly, using a thin, lighted tube with a camera.lapar/o abdomen-scopy looking with an instrumentFull entry Close or with a robot. Chapter 34 teaches the operations.

Inside the kidney

Cut a kidney from top to bottom and it shows two zones and a set of collecting funnels.

• Renal cortexcortexKOR-teksThe outer layer of an organ, especially the folded gray outer layer of the brain.cortic/o cortex, outer layerFull entry Close: the outer zone, lighter in color. It holds the filtering parts of every nephronnephronNEF-ronThe tiny filtering unit of the kidney, where blood is filtered and urine is made.nephr/o kidneyFull entry Close.
• Renal medullamedullamuh-DUL-uhThe inner part of an organ; most often the medulla oblongata, the lowest part of the brainstem.Full entry Close: the inner zone. It holds the renal pyramids, with their wide bases against the cortex and their tips, the renal papillae, pointing toward the center. The papillae are bundles of collecting ducts.
• Renal columns: bands of tissue that reach down from the cortex between the pyramids and carry blood vessels.
• Minor calyces (singular calyx): small cups that catch urine dripping from the papillae.
• Major calyces: larger cups formed where minor calyces join.
• Renal pelvis: a funnel formed where the major calyces meet. Smooth musclesmooth musclesmooth MUS-ulMuscle that works without conscious control and lines hollow organs such as the stomach, intestines, bladder, airways and blood vessels.Full entry Close in its wall pushes urine into the ureterureterYOOR-uh-terOne of the two tubes that carry urine from the kidneys down to the bladder.Full entry Close.
• Renal hilum: the notch on the inner (medial) side where the renal artery, renal vein, nerves, lymphlymphLIMFThe clear fluid that flows through the lymphatic vessels and carries white blood cells.Full entry Close vessels and the renal pelvis enter and leave. The renal pelvis lies behind the blood vessels there.

Stones often lodge in the renal pelvis. In a percutaneous nephrolithotomy (PCNL), the surgeon passes a nephroscope through the skin into the kidney and breaks up and removes them.

The renal artery and vein

Each kidney has one main artery and one main vein. Chapter 5 traces them with the rest of the circulation.

• The renal artery branches straight off the abdominal aorta.
• The renal vein carries the cleaned blood straight into the inferior vena cavainferior vena cavain-FEER-ee-er VEE-nuh KAY-vuhThe large vein that carries blood from the lower body back to the right atrium of the heart.inferior lowervena veincava hollowFull entry Close.

Inside the kidney, the artery divides again and again, into segmental, interlobar, arcuate and cortical radiateradiateRAY-dee-ateTo spread outward from one place to another, as pain can spread from where it starts.Full entry Close arteries, and finally into tiny afferentafferentAF-er-entCarrying something toward a center or organ, such as nerve signals toward the brain.af- (ad-) towardfer carry-ent doingFull entry Close arteriolesarteriolear-TEER-ee-ohlA very small artery that carries blood from an artery into the capillaries.arteri/o artery-ole smallFull entry Close, one to each nephron.

The renal artery, the renal vein, their nerves and lymph vessels together are called the pediclepediclePED-ih-kulA narrow stem or stalk that attaches a structure, such as a tumor or a skin flap, to the body.Full entry Close of the kidney, and the surgeon controls the pedicle when a kidney is removed.

The left renal vein is longer than the right, so a living donor usually gives the left kidney. In a kidney transplant, the new kidney goes into the recipient's iliaciliacIL-ee-akHaving to do with the ilium, the large, wing-shaped upper part of the hip bone.Full entry Close fossafossaFOS-uhA shallow hollow or dip in a bone or on the body's surface.Full entry Close, low in the pelvis on one side, and its renal artery is joined to the recipient's iliac artery.

Kidney Transplant32 instruments · 2 photos

The nephron

The nephron is the kidney's working unit, the smallest part that can make urine. Each kidney has about a million of them.

Each nephron has a filter at its start and a long tube after it.

1. Glomerulusglomerulusgloh-MAIR-yuh-lusA tiny ball of capillaries in the kidney that filters the blood as the first step in making urine.Full entry Close: a tuft of capillariescapillaryKAP-ih-lair-eeOne of the tiniest blood vessels, joining the smallest arteries to the smallest veins.Full entry Close under high pressure, fed by an afferent arteriole and drained by an efferentefferentEF-er-entCarrying something away from a center or organ, such as nerve signals from the brain to the muscles.ef- (ex-) away fromfer carry-ent doingFull entry Close arteriole.
2. Bowman's capsule (glomerularglomerulargloh-MAIR-yuh-lerRelating to the glomerulus, the tiny cluster of capillaries in each nephron of the kidney that filters the blood.glomerul/o glomerulus (little ball)-ar relating toFull entry Close capsule): the cup at the start of the tubuletubuleTOO-byoolA very small tube in the body, most often one of the tiny tubes in the kidney that turn filtered fluid into urine.Full entry Close that wraps the glomerulus and catches the fluid filtered out of it. The glomerulus and Bowman's capsule together are the renal corpuscle.
3. Renal tubule: the tube that carries the filtered fluid away and refines it. It has three parts.

• The proximalproximalPROK-sih-mulNearer the center of the body, or nearer the place where a part is attached.Full entry Close convoluted tubule (PCT), a twisting stretch whose lining cells have a brush border of microvilli. It does more reabsorbing than any other part.
• The loop of Henleloop of Henleloop uv HEN-leeThe U-shaped part of each nephron in the kidney that helps decide how concentrated the urine is.Full entry Close, a hairpin that dips down toward or into the medulla (descending limb) and comes back up (ascending limb). About 15 percent of nephrons have long loops that reach deep into the medulla.
• The distal convoluted tubule (DCT), a shorter twisting stretch back in the cortex.

1. Collecting duct: each one gathers fluid from several nephrons and carries it down through a pyramid to a papilla. Strictly, it is not part of the nephron.

After the glomerulus, the efferent arteriole forms a second set of capillaries, the peritubular capillaries and the vasa recta, that wrap the tubule and take back what it reabsorbsreabsorptionree-ab-SORP-shunThe taking back of water and dissolved substances from the fluid in the kidney tubules into the blood.re- again, backabsorb take in-tion processFull entry Close.

The juxtaglomerular apparatus (JGA) sits where the distal convoluted tubule touches the arterioles of its own glomerulus.

• The macula densa, a patch of cells in the wall of the distal tubule, senses the fluid flowing past.
• The juxtaglomerular cells, modified muscle cells in the wall of the afferent arteriole, adjust the blood flow into the glomerulus and release renin.

How urine is made

The nephron makes urine in three steps.

1. Filtrationfiltrationfil-TRAY-shunThe passing of fluid through a filter or membrane, which holds back larger particles; in the kidneys, the first step in making urine.filtr strain through-ation processFull entry Close: blood pressure in the glomerulus pushes part of the plasmaplasmaPLAZ-muhThe pale yellow liquid part of the blood, which carries the blood cells, proteins, nutrients and wastes.Full entry Close through the capillary wall into Bowman's capsule. The filter works mostly by size: water, salts, glucose, amino acidsamino aciduh-MEE-noh AS-idOne of the small building blocks that join together in chains to make proteins.Full entry Close, vitamins and wastes pass, but blood cells, plateletsplateletPLAYT-litA tiny cell fragment in the blood that sticks together at a wound to help form a clot.Full entry Close and large proteins such as albuminalbuminal-BYOO-minThe main protein in blood plasma, made by the liver, which holds fluid inside the blood vessels and carries drugs and hormones.Full entry Close stay in the blood.
2. Reabsorption: as the fluid moves along the tubule, the tubule takes back what the body needs and returns it to the blood. About two thirds of the water, sodium and potassium, and nearly all of the glucose, amino acids and vitamins, are taken back in the proximal tubule. The loop of Henle, the distal tubule and the collecting ducts take back more.
3. Secretionsecretionsih-KREE-shunA substance a gland or cell makes and releases, such as mucus, saliva, sweat or a hormone.Full entry Close: the tubule also moves some substances from the blood into the fluid, such as hydrogen ions (acid), potassium, creatininecreatininekree-AT-uh-neenA waste product of muscle that the kidneys remove from the blood; its blood level is used to measure how well the kidneys work.Full entry Close and some drugs, such as penicillinpenicillinspen-ih-SIL-inzA group of antibiotics, including penicillin and amoxicillin, that kill bacteria by stopping them from building their cell walls.Full entry Close.

The numbers show how much reabsorption matters. The kidneys filter about 125 mL of fluid a minute in a male and 105 mL in a female, roughly 150 to 180 liters a day, and they send about 99 percent of it back into the blood. What is left, about 1 to 2 liters a day, is urine. The rate of filtration is the glomerular filtration rateglomerular filtration rategloh-MER-yuh-ler fil-TRAY-shun RAYTHow much blood the kidneys filter each minute, used as the main measure of kidney function.Full entry Close (GFR).

Filtration depends on blood pressure. Muscle in the arteriole walls keeps it fairly steady through ordinary swings, but if the mean arterial pressuremean arterial pressureMEEN ar-TEER-ee-ul PRESH-erThe average pressure in the arteries over one heartbeat, used as a measure of how well blood reaches the organs.Full entry Close falls below about 60 mm Hg, as in shock, the kidneys can no longer filter properly.

A blood test shows how well the kidneys filter. Creatinine, a waste made by muscle, is filtered and hardly reabsorbed, so a rising serum creatinine means the kidneys are clearing less; the GFR is estimated from it.

The kidneys and blood pressure

When blood pressure falls, the kidneys help raise it again through the renin-angiotensin-aldosterone systemrenin-angiotensin-aldosterone systemREE-nin an-jee-oh-TEN-sin al-DOS-ter-ohn SIS-tumA chain of hormones that raises blood pressure and helps the body hold on to salt and water.Full entry Close (RAAS).

1. The juxtaglomerular cells sense the drop and release the enzymeenzymeEN-zimeA protein that speeds up a chemical reaction in the body without being used up.Full entry Close renin into the blood.
2. Renin turns angiotensinogen, a protein made by the liver, into angiotensin I.
3. An enzyme from the lungs, angiotensin-converting enzyme (ACEACEayss, or ay-see-eeAn abbreviation with several meanings, such as angiotensin-converting enzyme or adverse childhood experiences; the setting shows which.Full entry Close), turns angiotensin I into active angiotensin II.
4. Angiotensin II narrows blood vessels all over the body, which raises the pressure within moments.
5. Angiotensin II also makes the adrenal cortexadrenal cortexuh-DREE-nul KOR-teksThe outer layer of each adrenal gland, which makes the steroid hormones cortisol and aldosterone.ad- nearren kidney-al relating tocortex outer layer (Latin, bark)Full entry Close release aldosteronealdosteroneal-DOS-tuh-rohnA hormone from the adrenal glands that makes the kidneys keep sodium and water and get rid of potassium.aldo- from aldehyde (a chemical group)-sterone steroid hormoneFull entry Close, which makes the kidneys keep sodium. Water follows the sodium, so blood volume and pressure stay up for longer.

The kidney does not release angiotensin itself: its renin starts the chain that makes it.

A second hormone, antidiuretic hormoneantidiuretic hormonean-tee-dy-yoo-RET-ik HOR-mohnA hormone from the pituitary gland that tells the kidneys to hold on to water, making the urine more concentrated.anti- againstdiuretic making urineFull entry Close (ADH, also called vasopressinvasopressinvay-zoh-PRES-inA man-made form of antidiuretic hormone, given by IV mainly to raise blood pressure in shock.Full entry Close), comes from the posterior pituitary. When blood volume falls by 5 to 10 percent, ADH opens water channels in the collecting ducts so the kidneys keep more water, and it also narrows blood vessels.

Chapter 9 teaches these hormones, chapter 11 shock, and chapter 12 the drugs that act on this system, such as diureticsdiureticdy-yoo-RET-ikA drug that makes the kidneys pass more water and salt out of the body as urine.dia- throughur/o urine-etic relating toFull entry Close and ACE inhibitorsACE inhibitorAYS in-HIB-ih-terA blood pressure drug that blocks the enzyme that makes angiotensin II, so blood vessels relax and less fluid is held in the body.Full entry Close.

Vitamin D, calcium and red cells

• Vitamin D: the liver changes vitamin D into an inactive form, and the kidney adds the final step that makes calcitriolcalcitriolkal-sih-TRY-olThe active form of vitamin D, given as a drug to raise calcium absorption or, as an ointment, for psoriasis.Full entry Close, the active form. Parathyroid hormoneparathyroid hormonepar-uh-THY-royd HOR-mohnA hormone from the parathyroid glands in the neck that raises the calcium level in the blood.para- besidethyr/o thyroid-oid resemblingFull entry Close switches this step on when blood calcium is low. Calcitriol makes the gut absorb more calcium.
• Calcium: the kidney also takes back more calcium from the urine when parathyroid hormone calls for it.
• Red cells: the kidneys make about 85 percent of the body's EPOerythropoietinih-rith-roh-POY-uh-tinA hormone made mainly by the kidneys that tells the bone marrow to make red blood cells.erythr/o red-poietin substance that makesFull entry Close, more when the body needs oxygen, such as after heavy bleeding. Patients with kidney failurerenal failureREE-nul FAYL-yerLoss of the kidneys' ability to filter waste and extra fluid from the blood.ren kidney-al relating toFull entry Close lose this and become anemicanemiauh-NEE-mee-uhA lower than normal number of red blood cells or amount of hemoglobin in the blood.a- without, lacking-emia blood conditionFull entry Close.

4The ureters

The ureterureterYOOR-uh-terOne of the two tubes that carry urine from the kidneys down to the bladder.Full entry Close is a muscular tube that carries urine from the renal pelvis to the bladder. There are two, one from each kidney.

Its course

Each ureter follows a gentle S-shaped path.

1. It starts where the renal pelvis narrows, at the ureteropelvic junction (UPJ).
2. It runs down behind the peritoneumperitoneumpair-ih-toh-NEE-umThe thin membrane that lines the belly cavity and covers most of the organs inside it.peri- aroundton stretched-eum a structureFull entry Close, lying on the psoas muscle.
3. It crosses over the iliaciliacIL-ee-akHaving to do with the ilium, the large, wing-shaped upper part of the hip bone.Full entry Close vessels at the brim of the pelvis.
4. In the pelvis it sweeps out along the side wall, then turns in toward the bladder.
5. It pierces the back of the bladder wall at a slant and opens into the bladder at the ureterovesical junction (UVJ).

The slanted path through the bladder wall acts as a one-way valve: as the bladder fills and squeezes, it presses the tunnel shut, so urine cannot flow back up toward the kidney. Backward flow is called reflux; a child whose ureter lacks this slant is prone to reflux and serious urinary tract infections.

Size and wall

• In an adult, each ureter is about 25 to 30 cm long and about 4 to 5 mm across.
• Its lining is transitional epitheliumepitheliumep-ih-THEE-lee-umThe tissue that covers the body's surfaces and lines its organs, vessels and cavities.Full entry Close, which can stretch, with scattered goblet cells that make protective mucus.
• Its middle layer is smooth musclesmooth musclesmooth MUS-ulMuscle that works without conscious control and lines hollow organs such as the stomach, intestines, bladder, airways and blood vessels.Full entry Close. Waves of contraction, peristalsisperistalsispair-ih-STAWL-sisWaves of muscle squeezing that push food and waste along the digestive tract.peri- around-stalsis squeezing, contractionFull entry Close, push urine down the ureter without help from gravity.
• A loose outer coat of collagencollagenKOL-uh-jenThe main structural protein of the body, which gives strength to skin, bones, tendons, ligaments and scar tissue.coll/a glue-gen producingFull entry Close and fat anchors it to the back wall.

The ureter is narrowest in three places, which is where kidney stoneskidney stoneKID-nee STOHNA hard, pebble-like lump of minerals that forms inside the kidney.Full entry Close tend to stick and cause pain and blockage: the UPJ, the spot where it crosses the iliac vessels, and the UVJ.

In a ureteroscopy, the urologist passes a thin scope up through the urethraurethrayoo-REE-thruhThe tube that carries urine from the bladder out of the body.Full entry Close and bladder into the ureter and renal pelvis to look, take a biopsy, or break up and remove stones.

5The bladder

Where it sits

The bladder (urinary bladder) is a hollow muscular sac that stores urine.

• It lies in the pelvis just behind the pubic symphysissymphysisSIM-fih-sisA joint where two bones are joined firmly by a pad of cartilage that allows only a little movement.Full entry Close.
• In a female, the uterus and the vagina lie behind it. In a male, the rectum lies behind it and the prostateprostatePROS-taytA walnut-sized gland below the bladder in males that surrounds the urethra and makes part of the fluid in semen.Full entry Close below it.
• Like the kidneys and uretersureterYOOR-uh-terOne of the two tubes that carry urine from the kidneys down to the bladder.Full entry Close, it lies outside the peritonealperitonealper-ih-toh-NEE-ulHaving to do with the peritoneum, the thin lining of the belly cavity and the organs inside it.Full entry Close cavity: peritoneumperitoneumpair-ih-toh-NEE-umThe thin membrane that lines the belly cavity and covers most of the organs inside it.peri- aroundton stretched-eum a structureFull entry Close covers only its top, the dome. As the bladder fills, the dome rises into the abdomen.

Because the bladder lies below the peritoneum, the surgeon can reach it through a suprapubic incision, just above the pubic bonepubisPYOO-bisThe front part of each hip bone, low in the pelvis; the two meet in the middle at the pubic symphysis.pub/o pubisFull entry Close, without entering the peritoneal cavity.

Its parts

• Dome: the top, which rises as the bladder fills.
• Trigone: a smooth triangle on the floor of the bladder. Its three corners are the two ureteral openings, about 2.5 cm apart, and the opening of the urethraurethrayoo-REE-thruhThe tube that carries urine from the bladder out of the body.Full entry Close. The surgeon looks for these openings at cystoscopy.
• Bladder neck: the funnel at the bottom where the urethra begins. Muscle fibers of the bladder wall gather here to form the internal sphinctersphincterSFINGK-terA ring of muscle that tightens to close an opening or passage in the body and relaxes to open it.Full entry Close.

The wall

The wall has layers suited to stretching.

1. Mucosamucosamyoo-KOH-suhThe moist lining of body passages that open to the outside, such as the mouth, nose, gut and bladder.Full entry Close: the mucous membrane lining, made of transitional epitheliumepitheliumep-ih-THEE-lee-umThe tissue that covers the body's surfaces and lines its organs, vessels and cavities.Full entry Close. When the bladder is empty it lies in folds (rugae), and its surface cells are cube-shaped; when the bladder stretches, the folds flatten and the surface cells flatten too.
2. Submucosa: connective tissueconnective tissuekuh-NEK-tiv TISH-ooBody tissue that supports, binds together and protects other tissues and organs.Full entry Close under the lining.
3. Detrusor muscle: crisscrossing bands of smooth musclesmooth musclesmooth MUS-ulMuscle that works without conscious control and lines hollow organs such as the stomach, intestines, bladder, airways and blood vessels.Full entry Close that squeeze the bladder to empty it.
4. Outer covering: peritoneum (serosa) over the dome, and a connective tissue adventitia elsewhere.

The Core Curriculum's list names the layers as the mucous membrane, the muscle and the wall.

Storing and emptying urine

An adult bladder holds from nearly nothing up to about 500 to 600 mL; references give its full capacity as anywhere from 350 to 700 mL.

Two rings of muscle keep it closed.

• The internal urethral sphincter, at the bladder neck, is smooth muscle under automatic (autonomicautonomicaw-tuh-NOM-ikWorking on its own, without conscious control; used for the nerves that run the organs.auto- selfnom/o rule, law-ic relating toFull entry Close) control.
• The external urethral sphincter, lower down where the urethra passes through the pelvic floor, is skeletal muscleskeletal muscleSKEL-uh-tul MUS-ulMuscle attached to bones that a person moves by choice, such as the muscles of the arms and legs.Full entry Close that you control. Its nerve is the pudendal nerve, from the sacralsacralSAY-krulHaving to do with the sacrum, the triangle-shaped bone at the base of the spine between the hip bones.Full entry Close spinal cord (S2 to S4).

Emptying the bladder is called micturition, urination or voiding.

1. While the bladder fills, sympathetic nerves keep the detrusor relaxed and the external sphincter stays tight.
2. Stretch receptorsreceptorrih-SEP-terA structure on or in a cell that a specific chemical, such as a hormone or drug, attaches to in order to act.Full entry Close in the wall send signals to the sacral spinal cord. At about 150 mL, you feel the first urge, which is easy to ignore.
3. To void, parasympatheticparasympatheticpair-uh-sim-puh-THET-ikRelating to the part of the autonomic nervous system that calms the body and supports "rest and digest" functions.para- besidesympathetic the other autonomic divisionFull entry Close nerves make the detrusor contract and the internal sphincter relax, and you relax the external sphincter.
4. As the bladder keeps filling, the urge grows; at about 300 to 400 mL, control may be lost.

The ability to hold urine is continence. Losing control of urine is incontinenceincontinencein-KON-tih-nensLoss of control over the bladder or bowel, so urine or stool leaks out without the person meaning it to.in- notcontin/o to hold back-ence state ofFull entry Close; being unable to empty the bladder is urinary retentionurinary retentionYUR-ih-nair-ee rih-TEN-shunBeing unable to empty the bladder completely, or at all.Full entry Close. In late pregnancy the growing uterus presses on the bladder, so it holds less and must be emptied more often. With age, the bladder loses muscle tone and may not empty completely.

Stress urinary incontinenceurinary incontinenceYOOR-ih-nair-ee in-KON-tih-nunsLeaking of urine that a person cannot control.Full entry Close is a leak of urine when pressure in the abdomen rises, such as with a cough or a sneeze. A sling placed under the urethra supports it at those moments and is now the usual operation for stress incontinence in females.

6The urethra

The urethraurethrayoo-REE-thruhThe tube that carries urine from the bladder out of the body.Full entry Close carries urine from the bladder out of the body. It is the one urinary organ that differs clearly between females and males.

In both, it starts at the bladder neck, at the lower corner of the trigone, and passes through the internal and then the external sphinctersphincterSFINGK-terA ring of muscle that tightens to close an opening or passage in the body and relaxes to open it.Full entry Close. Its lining starts as transitional epitheliumepitheliumep-ih-THEE-lee-umThe tissue that covers the body's surfaces and lines its organs, vessels and cavities.Full entry Close, like the bladder's, and ends as stratified squamous epithelium near the opening. MucousmucousMYOO-kusRelating to mucus or making mucus, as in mucous membrane.Full entry Close glands along it protect it from the acid or alkali in urine.

The female urethra

• It is short, about 4 cm long (references give 3 to 5 cm), and runs just behind and below the pubic symphysissymphysisSIM-fih-sisA joint where two bones are joined firmly by a pad of cartilage that allows only a little movement.Full entry Close.
• It lies against the front wall of the vagina.
• Its opening, the external urinary meatusurinary meatusYOOR-ih-nair-ee mee-AY-tusThe opening at the end of the urethra through which urine leaves the body.Full entry Close, lies in the vestibule below the clitorisclitorisKLIT-er-isA small, very sensitive organ at the top of the vulva, where the inner folds of skin meet.Full entry Close and above the vaginal opening, between the labia minora.
• The small Skene glands (paraurethral glands) open beside the meatusmeatusmee-AY-tusAn opening or passage in the body, such as the urinary opening or the ear canal.Full entry Close.
• It carries only urine.

Because it is short and close to the vagina and anus, germs reach the bladder more easily, which is the main reason urinary tract infections are more common in females. Chapter 10 teaches these infections.

The male urethra

The male urethra is about 20 cm long (references give 20 to 25 cm). It runs from the bladder neck through the prostateprostatePROS-taytA walnut-sized gland below the bladder in males that surrounds the urethra and makes part of the fluid in semen.Full entry Close, through the floor of the pelvis and the length of the penis to the tip. It carries urine, and during ejaculationejaculationih-jak-yuh-LAY-shunThe release of semen from the penis, usually at orgasm.Full entry Close it carries semen. It has four parts:

1. Preprostatic urethra: a very short part within the wall of the bladder neck.
2. Prostatic urethra: about 3 cm long and the widest part, running through the middle of the prostate. On its floor is a small mound, the verumontanum, where the two ejaculatory ducts open.
3. Membranous urethra: the shortest part, about 2.5 cm, passing through the muscles of the pelvic floor, where the external sphincter surrounds it.
4. Spongy (penile) urethra: running inside the corpus spongiosum of the penis to the external urethral meatus at the tip of the glans.

Because the prostate wraps around the urethra, an enlarged prostate can squeeze it and make urination difficult. Chapter 31 explains why this matters when a catheter is passed.

In a cystoscopy, the urologist passes a scope through the urethra to look at the urethra, the bladder lining and the ureteralureterYOOR-uh-terOne of the two tubes that carry urine from the kidneys down to the bladder.Full entry Close openings; in a male, the verumontanum, the bladder neck and the lobes of the prostate are checked too.

7Urine

What normal urine is made of

A healthy adult makes about 1 to 2 liters of urine a day. It is about 95 percent water and 5 percent dissolved substances.

Fresh normal urine has little or no smell, and its color runs from pale yellow to deep amber. Dark, concentrated urine, sometimes with a slight smell of ammonia, often means the person is short of water. The smell of ammonia in a stale sample comes from bacteria breaking down urea after it leaves the body.

Specific gravity compares the weight of urine with the weight of the same amount of pure water, which is 1.000. Urine is always heavier than water because of what is dissolved in it, so the number shows how concentrated it is: high when the patient is dehydrated, low when the urine is dilute.

The amount matters too. Oliguriaoliguriaol-ih-GYOOR-ee-uhMaking less urine than normal, in an adult below about 400 mL a day.olig/o few, scantur/o urine-ia conditionFull entry Close is too little urine, about 300 to 500 mL a day or less; the body needs to make at least about 500 mL a day to get rid of its wastes. Anuriaanuriaan-YOOR-ee-uhMaking little or no urine: less than about 50 to 100 mL in 24 hours in an adult.an- without-uria urineFull entry Close is almost no urine, and polyuriapolyuriapol-ee-YOOR-ee-uhPassing an abnormally large amount of urine, usually more than about 2.5 to 3 liters a day in an adult.poly- many, muchur/o urine-ia conditionFull entry Close is too much, more than about 2.5 to 3 liters a day.

What should not be in urine

Blood in a sample taken during a menstrual period is contamination, not a sign of disease.

The urinalysis

A urinalysis checks the urine for both normal and abnormal substances, and it is a routine test before many operations.

• Looking at it: the color, clarity and odor.
• Dipstick: a strip coated with chemicals that change color to show albumin (protein), bilirubinbilirubinbil-ih-ROO-binA yellow pigment made when old red blood cells break down, which the liver clears into bile.Full entry Close, glucose, ketones, leukocytes, blood, nitrite and urobilinogen; the pH and specific gravity are read too.
• Microscope: the sample is spun in a centrifuge, and the sediment at the bottom is checked for cells, germs, crystals and casts.
• Culture: when infection is suspected, a culture finds the exact germ, and a sensitivitysensitivitysen-sih-TIV-ih-teeHow strongly something responds; in lab work, which drugs stop a germ, or how well a test finds people who have a disease.Full entry Close test shows which antibiotics will work. Chapter 10 teaches culture and sensitivityculture and sensitivityKUL-cher and sen-sih-TIV-ih-teeA lab test that grows the germs from a sample to identify them and see which antibiotics work against them.Full entry Close.

The sample may be caught as the patient voids or taken through a catheter, and some tests use all the urine made over 24 hours.

8The female reproductive system

The female reproductive organs make egg cells and hormones, receive sperm, carry and nourish a pregnancy, and deliver the baby. Most of them lie inside the pelvis.

The external genitalia

The external organs together are called the vulva.

• Mons pubispubisPYOO-bisThe front part of each hip bone, low in the pelvis; the two meet in the middle at the pubic symphysis.pub/o pubisFull entry Close: a pad of fat over the pubic bone, covered with hair after puberty.
• Labia majora: two outer folds of skin over fat, covered with hair, that run back from the mons and protect the structures between them.
• Labia minora: two thinner, hairless folds inside the labia majora that protect the urethralurethrayoo-REE-thruhThe tube that carries urine from the bladder out of the body.Full entry Close and vaginal openings. In front, they join to form a hood over the clitorisclitorisKLIT-er-isA small, very sensitive organ at the top of the vulva, where the inner folds of skin meet.Full entry Close, the prepuce.
• Clitoris: a small, very sensitive organ of erectile tissue at the front where the labia minora meet. It develops from the same tissue as the penis but does not contain the urethra.
• Vestibule: the area enclosed by the labia minora. It holds the urinary meatusurinary meatusYOOR-ih-nair-ee mee-AY-tusThe opening at the end of the urethra through which urine leaves the body.Full entry Close in front and the vaginal opening, the introitus, behind it.
• Hymen: a thin fold of tissue that may partly surround the vaginal opening.
• Perineumperineumpair-ih-NEE-umThe area of skin and muscle between the genitals and the anus.perine/o perineumFull entry Close: the area between the vaginal opening and the anus. Under its skin lie strong muscles of the pelvic floor. In childbirth it may be cut to keep it from tearing as the baby's head comes out, an episiotomyepisiotomyeh-pee-zee-OT-uh-meeA cut made in the perineum, the tissue between the vagina and the anus, during birth to widen the opening.episi/o vulva, perineum-otomy cutting intoFull entry Close.

Two pairs of small glands open into the vestibule.

• The Bartholin glandsBartholin glandsBAR-tuh-lin glandzTwo small glands, one on each side of the vaginal opening, that make fluid to moisten the vagina.Full entry Close (greater vestibular glands) lie on each side of the vaginal opening, at about the 5 and 7 o'clock positions. They make mucus that keeps the area moist, and they can become infected and need to be opened and drained. They match the bulbourethral glands in the male.
• The Skene glands (paraurethral glands) lie beside the urethra and open next to the urinary meatus.

The vagina

The vagina is a muscular canal, about 10 cm long, that runs from the vestibule to the cervix.

• Its front wall, about 6 to 8 cm long, lies against the bladder and urethra; its back wall, about 7 to 10 cm, lies against the rectum.
• The cervix pokes into its top. The recesses around the cervix are the fornices: front, back and one on each side. The back (posterior) fornix touches the peritoneumperitoneumpair-ih-toh-NEE-umThe thin membrane that lines the belly cavity and covers most of the organs inside it.peri- aroundton stretched-eum a structureFull entry Close of the posterior cul-de-sac, the pouch of Douglas (see the uterus, below).
• Its wall has a lining of stratified squamous epitheliumepitheliumep-ih-THEE-lee-umThe tissue that covers the body's surfaces and lines its organs, vessels and cavities.Full entry Close with folds (rugae) that let it stretch, a middle layer of smooth musclesmooth musclesmooth MUS-ulMuscle that works without conscious control and lines hollow organs such as the stomach, intestines, bladder, airways and blood vessels.Full entry Close, and an outer fibrousfibrousFY-brusMade of or containing tough threads (fibers), especially of connective tissue.fibr/o fiber-ous full of, relating toFull entry Close layer.
• Helpful bacteria, mostly Lactobacillus, keep it acidic, below pH 4.5, which holds back harmful germs.
• It receives the penis and semen during intercourse, lets menstrual blood out, and is the last part of the birth canal.

The ovaries

The ovaries are the female gonadsgonadGOH-nadA sex gland: an ovary or a testis, which makes eggs or sperm and sex hormones.gon seed, generationFull entry Close, each about the size and shape of an almond, about 2 to 4 cm long, one on each side of the uterus.

• What holds them: each ovary hangs from the back of the broad ligament by a fold of peritoneum, the mesovarium. The ovarian ligament ties it to the uterus, and the suspensory ligament, also called the infundibulopelvic ligament, carries its blood vessels from the side wall of the pelvis.
• How they are built: a thin layer of epithelium, not peritoneum, covers each ovary. Its outer cortexcortexKOR-teksThe outer layer of an organ, especially the folded gray outer layer of the brain.cortic/o cortex, outer layerFull entry Close holds the folliclesfollicleFOL-ih-kulA small sac or cavity in the body, such as the pocket a hair grows from or the sac in the ovary that holds an egg.Full entry Close, each an egg cell with its supporting cells; its inner medullamedullamuh-DUL-uhThe inner part of an organ; most often the medulla oblongata, the lowest part of the brainstem.Full entry Close holds the blood vessels, lymphlymphLIMFThe clear fluid that flows through the lymphatic vessels and carries white blood cells.Full entry Close vessels and nerves.
• Oocyte formation: the egg cells, called oocytes, form before birth. A newborn has about 1 to 2 million, about 400,000 remain at puberty, and almost none are left by the end of menopausemenopauseMEN-uh-pawzThe time in a woman's life when menstrual periods stop for good, counted once there has been no period for 12 months in a row.men/o month, menstruation-pause stopFull entry Close. Usually one is released each cycle.
• Hormones: the growing follicles make estrogenestrogenES-truh-jenA female sex hormone, made mainly by the ovaries, and the group of drugs that act like it.Full entry Close, which builds up the lining of the uterus and brings on the body changes of puberty. After an egg is released, the empty follicle becomes the corpus luteum and makes progesteroneprogesteroneproh-JES-tuh-rohnA female sex hormone that prepares the lining of the uterus for pregnancy and helps keep a pregnancy going, also given as a drug.Full entry Close, which readies the lining for a pregnancy and keeps it going. The ovaries also make a little testosteronetestosteronetes-TOS-tuh-rohnThe main male sex hormone, made mostly in the testes and in small amounts by the ovaries and adrenal glands.test/o testis-sterone steroid hormoneFull entry Close.

The uterine tubesfallopian tubefuh-LOH-pee-un TOOBOne of the two tubes that carry an egg from the ovary to the uterus, where fertilization usually happens.Full entry Close, the ovaries and their ligaments together are called the adnexa.

The uterine (fallopian) tubes

The uterine tubes, also called the fallopian tubes or oviducts, carry the egg from the ovary to the uterus. Each fallopian tube is about 10 to 13 cm long.

From the uterus outward, each tube has four parts.

1. Interstitialinterstitialin-ter-STISH-ulRelating to the small spaces between cells or between the parts of a tissue or organ.Full entry Close (intramural) part: about 1 cm long, inside the wall of the uterus.
2. Isthmus: the narrow part next to the uterus.
3. Ampulla: the wide, winding middle, more than half the tube's length, where the egg is usually fertilizedfertilizationfer-tuh-lih-ZAY-shunThe joining of a sperm and an egg to form a single new cell, the start of a pregnancy.Full entry Close.
4. Infundibulum: the trumpet-shaped outer end, which opens into the peritonealperitonealper-ih-toh-NEE-ulHaving to do with the peritoneum, the thin lining of the belly cavity and the organs inside it.Full entry Close cavity and is fringed with finger-like fimbriae.

The tube does not touch the ovary. At ovulationovulationov-yuh-LAY-shunThe release of a mature egg from an ovary, usually once in each menstrual cycle.Full entry Close, the fimbriae sweep over the ovary and draw the egg in, and then beating ciliaciliaSIL-ee-uhTiny hair-like structures on the surface of some cells that move in waves.Full entry Close and waves of muscle in the tube move it toward the uterus. A fold of the broad ligament, the mesosalpinx, holds each tube.

Because the tube opens into the peritoneal cavity, germs that climb up through the vagina and uterus can reach the pelvis; an infection there is pelvic inflammatory diseasepelvic inflammatory diseasePEL-vik in-FLAM-uh-tor-ee dih-ZEEZInfection of the female upper reproductive organs: the uterus, fallopian tubes and ovaries.Full entry Close, which can scar the tubes. A pregnancy that implants outside the uterus is an ectopic pregnancyectopic pregnancyek-TOP-ik PREG-nun-seeA pregnancy in which the fertilized egg implants and grows outside the main cavity of the uterus, most often in a fallopian tube.ec- outtop/o place-ic relating toFull entry Close, and most of them grow in a tube.

The uterus

The uterus is a hollow, thick-walled, pear-shaped organ that holds and nourishes a pregnancy. When not pregnant, it is about 7 cm long and 5 cm wide. It sits in the pelvis between the bladder in front and the rectum behind, and it usually tips forward.

It has three regions.

• FundusfundusFUN-dusThe rounded top or base of a hollow organ, most often the top of the uterus.Full entry Close: the rounded top, above the openings of the uterine tubes.
• Body (corpus): the main part. A slight narrowing, the isthmus, separates it from the cervix.
• Cervix: the narrow neck, about 2 to 3 cm long, that pokes into the vagina. Its canal runs from the internal os, inside, to the external os, which opens into the vagina; the os opens wide in labor.

Its wall has three layers.

1. Perimetrium: the outer serousserousSEER-usThin, watery and clear to pale yellow, like the fluid part of blood.Full entry Close layer, the visceralvisceralVIS-er-ulHaving to do with the internal organs, especially those in the chest and belly.viscer/o internal organs-al relating toFull entry Close peritoneum that covers the uterus.
2. Myometrium: the thick middle layer of smooth muscle, most of the wall. Its fibers run in every direction, so it can contract strongly in labor and push out menstrual blood.
3. Endometriumendometriumen-doh-MEE-tree-umThe inner lining of the uterus, which thickens each month and is shed as the menstrual period if no pregnancy begins.endo- withinmetr/o uterus-ium tissueFull entry Close: the inner lining. Its deep basal layer stays put; its thicker functional layer grows each month under estrogen and progesterone and is shed in menstruation.

As the peritoneum drapes over the uterus, it dips into two pouches.

• In front, it folds forward from the uterus onto the bladder. This fold is the bladder flap, and the shallow pouch beneath it is the anterior cul-de-sac.
• Behind, it dips down between the uterus and the rectum to form the posterior cul-de-sac, the pouch of Douglas.

The uterine ligaments

Several ligaments hold the uterus in place, along with the muscles of the pelvic floor.

The cardinal ligaments give the uterus its main support; one reference also calls the broad ligament a primary support.

The uterine arteries, which run in the cardinal ligaments, and the ovarian arteries, which run in the suspensory ligaments, supply the uterus, tubes and ovaries.

An abdominal hysterectomyabdominal hysterectomyab-DOM-ih-nul his-ter-EK-tuh-meeSurgery to remove the uterus through a cut in the lower abdomen.hyster/o uterus-ectomy surgical removalFull entry Close removes the uterus, and a total hysterectomyhysterectomyhis-tuh-REK-tuh-meeSurgery to remove the uterus.hyster/o uterus-ectomy surgical removalFull entry Close takes the cervix with it. A salpingo-oophorectomy removes a uterine tube and its ovary; bilateral means both sides. Chapter 33 teaches these operations.

9The breast

The breasts are accessory organs of the female reproductive system. Their job is to make milk for a baby, which is called lactationlactationlak-TAY-shunThe making and release of milk by the breasts.lact/o milk-ation the process ofFull entry Close.

• Where it lies: each breast lies on the pectoralis major muscle, from about the 2nd to the 6th rib, with a tail of tissue, the tail of Spence, reaching toward the armpit.
• Mammary glands: the milk-making glands are modified sweat glands, arranged in about 15 to 20 lobes. Each lobe holds lobules of tiny sacs, the alveolialveolusal-VEE-uh-lus (plural alveoli, al-VEE-uh-ly)One of the tiny air sacs at the ends of the smallest airways in the lungs.Full entry Close, that make milk.
• Mammary ducts: each lobe drains through a lactiferous duct, which widens into a lactiferous sinussinusSY-nusA hollow space in the body, most often one of the air-filled spaces in the skull bones around the nose.Full entry Close just before it opens on the nipple.
• Nipple and areola: the nipple is the raised tip where the ducts open. The areola is the pigmented ring around it, with small areolar glands that make a lubricating fluid to protect the nipple during nursing.
• Fat and ligaments: fat around the lobes sets the breast's size, and bands of connective tissueconnective tissuekuh-NEK-tiv TISH-ooBody tissue that supports, binds together and protects other tissues and organs.Full entry Close, the suspensory (Cooper) ligaments, attach the breast to the skin.

Most of the breast's lymphlymphLIMFThe clear fluid that flows through the lymphatic vessels and carries white blood cells.Full entry Close drains to the lymph nodeslymph nodelimf nohdA small, bean-shaped organ of the immune system that filters lymph fluid and holds white blood cells.Full entry Close in the armpit, which is why surgeons check them for the spread of breast cancer. A lumpectomy removes the mass with margins free of cancer cells and keeps the rest of the breast, a form of breast-conserving surgery. Chapter 5 teaches the sentinel node, chapter 32 breast surgery, and chapter 38 breast reconstruction.

Lumpectomy26 instruments · 2 photos

10The menstrual cycle

From the first period (menarchemenarcheMEN-ar-keeA person's first menstrual period.men/o month, menstruationarche beginning (Greek)Full entry Close) until periods stop (menopausemenopauseMEN-uh-pawzThe time in a woman's life when menstrual periods stop for good, counted once there has been no period for 12 months in a row.men/o month, menstruation-pause stopFull entry Close), the ovaries and uterus go through a repeating cycle, usually about 28 days long, though 21 to 32 days is common. Day 1 is the first day of bleeding. Hormones from the hypothalamushypothalamushy-poh-THAL-uh-musA small area at the base of the brain that controls body temperature, hunger, thirst, sleep and many hormones.hypo- belowthalamus inner chamber (a part of the brain)Full entry Close and pituitary drive the cycle; chapter 9 teaches them.

Two cycles run side by side: one in the ovary, one in the lining of the uterus.

In the ovary

1. FollicularfollicleFOL-ih-kulA small sac or cavity in the body, such as the pocket a hair grows from or the sac in the ovary that holds an egg.Full entry Close phase (about days 1 to 14): pituitary hormones make several follicles grow and release estrogenestrogenES-truh-jenA female sex hormone, made mainly by the ovaries, and the group of drugs that act like it.Full entry Close. Usually only one, the dominant follicle, survives.
2. Ovulationovulationov-yuh-LAY-shunThe release of a mature egg from an ovary, usually once in each menstrual cycle.Full entry Close (about day 14 of a 28-day cycle): the dominant follicle makes so much estrogen that the pituitary releases a surge of luteinizing hormoneluteinizing hormoneLOO-tee-uh-ny-zing HOR-mohnA hormone from the pituitary gland that triggers ovulation in women and testosterone production in men.Full entry Close (LH). The surge makes the follicle burst and release its egg into the peritonealperitonealper-ih-toh-NEE-ulHaving to do with the peritoneum, the thin lining of the belly cavity and the organs inside it.Full entry Close cavity, where the fimbriae catch it.
3. Luteal phase (the rest of the cycle): the empty follicle becomes the corpus luteum and makes progesteroneprogesteroneproh-JES-tuh-rohnA female sex hormone that prepares the lining of the uterus for pregnancy and helps keep a pregnancy going, also given as a drug.Full entry Close. If no pregnancy starts within about 10 to 12 days, the corpus luteum breaks down and its progesterone falls.

In the uterus

The Core Curriculum names four phases. Other references count three, with ovulation as the line between the proliferative and secretory phases.

An egg lives only about a day after ovulation, but sperm can survive in the tubes for 3 to 5 days, so intercourse a few days before ovulation can still lead to pregnancy.

11Words for pregnancy

The Core Curriculum lists these terms.

A chart may write gravidity and parity as G and P: a patient who is pregnant now and has given birth once before, after 20 weeks, is G2 P1.

Some references, the Core Curriculum's list among them, write gravidity as "gravity".

A cesarean sectioncesarean birthsih-ZAIR-ee-un berthBirth of a baby through surgical cuts in the belly and the uterus.Full entry Close delivers the baby through incisions in the abdomen and the uterus. Chapter 33 teaches it.

12The male reproductive system

The male reproductive organs make sperm and the hormone testosteronetestosteronetes-TOS-tuh-rohnThe main male sex hormone, made mostly in the testes and in small amounts by the ovaries and adrenal glands.test/o testis-sterone steroid hormoneFull entry Close, and they carry sperm out of the body in semen. Unlike the female organs, many of them lie outside the pelvis.

The scrotum and testes

The scrotumscrotumSKROH-tumThe pouch of skin and muscle that holds the testicles.Full entry Close is a sac of skin and muscle that hangs behind the penis and in front of the anus. A wall down its middle, the scrotal septumseptumSEP-tumA wall of tissue that divides two spaces or cavities, such as the two sides of the heart or nose.sept/o wall, partitionFull entry Close, divides it into two compartments, one for each testis.

Sperm develop best at about 2 to 4 °C below body temperature, and the scrotum adjusts to keep them there. In the cold, the dartos muscle under its skin and the cremaster muscles around each testis pull the testes up against the body; in the warmth, they relax and let the testes hang lower.

The testes (singular testis), or testicles, are the male gonadsgonadGOH-nadA sex gland: an ovary or a testis, which makes eggs or sperm and sex hormones.gon seed, generationFull entry Close: two ovals, each about 4 to 5 cm long, that make sperm and testosterone.

• Tunica vaginalis: a smooth serousserousSEER-usThin, watery and clear to pale yellow, like the fluid part of blood.Full entry Close sac with two layers around each testis, holding a little clear fluid. A hydrocele is too much fluid collecting in it.
• Tunica albuginea: a tough white layer of dense connective tissueconnective tissuekuh-NEK-tiv TISH-ooBody tissue that supports, binds together and protects other tissues and organs.Full entry Close that covers the testis itself and sends walls inward, dividing it into 300 to 400 lobules.
• Seminiferous tubulestubuleTOO-byoolA very small tube in the body, most often one of the tiny tubes in the kidney that turn filtered fluid into urine.Full entry Close: tightly coiled tubes in each lobule, where sperm are made. The Sertoli cells in their walls support and protect the developing sperm.
• Leydig cells (interstitialinterstitialin-ter-STISH-ulRelating to the small spaces between cells or between the parts of a tissue or organ.Full entry Close cells): cells in the spaces between the tubules that make testosterone.

The making of sperm, spermatogenesis, starts at puberty and goes on for life. One round, from stem cellstem cellSTEM SELAn unspecialized cell that can divide to make more of itself and develop into specialized cells.Full entry Close to finished sperm, takes about 64 days, and the testes make about 100 to 300 million sperm a day. Finished sperm leave the tubules through a network of small ducts into the epididymisepididymisep-ih-DID-ih-misA coiled tube on the back of each testis where sperm mature and are stored.epi- upondidym testis (twin)Full entry Close.

Testosterone keeps sperm production going and builds muscle and bone, brings on the body changes of puberty, and maintains sex drive. Luteinizing hormoneluteinizing hormoneLOO-tee-uh-ny-zing HOR-mohnA hormone from the pituitary gland that triggers ovulation in women and testosterone production in men.Full entry Close from the pituitary controls how much is made; chapter 9 teaches this.

Before birth, during the seventh month, each testis moves down through the abdominal wall into the scrotum. A testis that has not come down by birth is an undescended testiscryptorchidismkrip-TOR-kih-diz-umA condition in which one or both testicles have not moved down into the scrotum.crypt/o hiddenorch/o testis-ism conditionFull entry Close (cryptorchidism); chapter 34 teaches the operation that brings it down.

In a hydrocelectomy, the surgeon removes the swollen, fluid-filled sac of tunica vaginalis.

The ducts

Sperm travel through a chain of ducts on their way out.

1. Epididymis: a tightly coiled tube along the back of each testis, about 6 m long if it were straightened out. Sperm take about 12 days to pass through it, and on the way they mature and become able to swim. They are stored in its tail until ejaculationejaculationih-jak-yuh-LAY-shunThe release of semen from the penis, usually at orgasm.Full entry Close, and its lining adds fluid that carries them along.
2. Ductus deferens, also called the vas deferens: a thick, muscular tube that carries sperm from the epididymis up inside the spermatic cord, through the inguinalinguinalING-gwih-nulRelating to the groin, the fold where the thigh meets the lower abdomen.Full entry Close canal into the pelvis, and over and behind the bladder, where it widens into the ampulla. Its muscle pushes the sperm along by peristalsisperistalsispair-ih-STAWL-sisWaves of muscle squeezing that push food and waste along the digestive tract.peri- around-stalsis squeezing, contractionFull entry Close.
3. Ejaculatory duct: a short duct, one on each side, formed where the ductus deferens joins the duct of the seminal vesiclevesicleVES-ih-kulA small, raised blister on the skin filled with clear fluid, less than 1 cm across.Full entry Close. It passes through the prostateprostatePROS-taytA walnut-sized gland below the bladder in males that surrounds the urethra and makes part of the fluid in semen.Full entry Close and opens into the prostatic urethraurethrayoo-REE-thruhThe tube that carries urine from the bladder out of the body.Full entry Close at the verumontanum.
4. Urethra: carries the semen out through the penis.

The Core Curriculum's list writes this duct as the "vastus ductus deferens"; its name is the ductus deferens, or vas deferens.

Because the ductus deferens runs near the skin in the scrotum, it is easy to reach. In a vasectomy, the surgeon cuts and seals a short piece of each one, which stops sperm from leaving and is a lasting form of birth control.

The spermatic cord and the inguinal canal

The spermatic cord is the bundle that runs from the abdominal wall to each testis and carries what it needs. It holds:

• the ductus deferens and its small artery;
• the testicular artery;
• the testicular veins, which form a net called the pampiniform plexusplexusPLEK-susA network of nerves or blood vessels that branch and join together.Full entry Close;
• the cremasteric artery and vein;
• nerves and lymphlymphLIMFThe clear fluid that flows through the lymphatic vessels and carries white blood cells.Full entry Close vessels;
• a remnant of the processus vaginalis, a pouch of peritoneumperitoneumpair-ih-toh-NEE-umThe thin membrane that lines the belly cavity and covers most of the organs inside it.peri- aroundton stretched-eum a structureFull entry Close.

The cremaster muscle wraps the cord and the testis. When the veins of the pampiniform plexus swell, they make a varicocele; it is more common on the left, because the left testicular (gonadal) vein drains into the left renal vein at a right angle, which puts more back pressure on it.

The inguinal canal is a tunnel through the lower abdominal wall, near the inguinal ligament. It runs from the deep inguinal ring, an opening in the transversalis fasciafasciaFASH-ee-uhA sheet or band of tough connective tissue that covers and separates muscles and organs.fasci/o bandFull entry Close, to the superficial inguinal ring. It carries the spermatic cord in a male and the round ligament of the uterus in a female. The weak area of the groin is larger in males, which matches the higher rate of inguinal herniasherniaHER-nee-uhA bulge of an organ or tissue through a weak spot in the muscle or tissue wall that normally holds it in.Full entry Close in males. Chapter 32 teaches hernias and their repair.

The glands and semen

Three kinds of glands add the fluid that makes up most of the semen.

• Seminal vesicles: two glands behind the bladder that make about 60 percent of the semen. Their fluid is rich in fructose, a sugar that fuels the sperm.
• Prostate: a walnut-sized gland, weighing about 20 to 30 g, that sits under the bladder in front of the rectum and wraps around the prostatic urethra. It adds a milky, alkaline fluid that first thickens the semen and then thins it again after ejaculation. It can be felt in a rectalrectalREK-tulRelating to the rectum, the last part of the large intestine; also, given or measured through the rectum.rect/o rectum, straight-al relating toFull entry Close exam.
• Bulbourethral glands, or Cowper glands: two small glands just below the prostate, beside the urethra. With arousal, before ejaculation, they release a thick mucus that lubricates the urethra and neutralizes acid left by urine.

Semen is the fluid that comes out in ejaculation, about 2 to 5 mL at a time. Sperm make up only about 5 percent of it; the rest comes from the glands.

The prostate grows again from about age 25. In many older patients it grows enough to squeeze the urethra, causing a frequent, urgent need to void, a weak stream and a bladder that never feels empty. This is benign prostatic hypertrophybenign prostatic hyperplasiabee-NINE proh-STAT-ik hy-per-PLAY-zhuhA prostate gland that has grown larger than normal, from growth that is not cancer.hyper- more than normalplas growth or formation-ia conditionFull entry Close (BPH), also called benign prostatic hyperplasia. A transurethral resection of the prostatetransurethral resection of the prostatetrans-yoo-REE-thrul rih-SEK-shun of the PROS-taytSurgery that removes part of the prostate gland with an instrument passed up through the urethra.trans- throughurethr/o urethra-al relating toresection cutting outFull entry Close (TURP) removes the obstructing tissue through the urethra with a resectoscope.

For prostate cancerprostate cancerPROS-tayt KAN-serCancer that starts in the prostate, the gland below the bladder in males that helps make semen.Full entry Close, a radical prostatectomy removes the whole prostate with the seminal vesicles. The nerves for erection run close beside the prostate, so when the tumor is still inside the prostate's capsule the surgeon may try to spare them; erectile dysfunctionerectile dysfunctionih-REK-tile dis-FUNK-shunRepeated trouble getting or keeping an erection firm enough for sex.dys- difficult, abnormalfunction workingFull entry Close and loss of urine control are known risks of the operation.

The penis

The penis carries the urethra and delivers semen.

• Shaft: three long columns of spongy erectile tissue, which fill with blood in an erection. The two larger corpora cavernosa (singular corpus cavernosum), side by side, make up most of it. The smaller corpus spongiosum, along the underside, surrounds the spongy urethra.
• Glans penis: the rounded tip, formed by the end of the corpus spongiosum and rich in nerve endings. The external urethral meatusurinary meatusYOOR-ih-nair-ee mee-AY-tusThe opening at the end of the urethra through which urine leaves the body.Full entry Close opens on it.
• Prepuce (foreskin): the fold of skin that covers the glans. Circumcisioncircumcisionsur-kum-SIZH-unSurgery to remove the foreskin, the skin that covers the tip of the penis.Full entry Close removes it.

A suspensory ligament holds the penis to the pubic symphysissymphysisSIM-fih-sisA joint where two bones are joined firmly by a pad of cartilage that allows only a little movement.Full entry Close.

Words for male reproduction

The Core Curriculum's list uses the older word impotence; today the term is erectile dysfunction.

13Where surgery meets these organs

The ureter in pelvic surgery

The ureterureterYOOR-uh-terOne of the two tubes that carry urine from the kidneys down to the bladder.Full entry Close runs close to the organs of the female pelvis. It comes down into the pelvis behind the ovary, near the ovarian vessels in the suspensory (infundibulopelvic) ligament, and then, beside the cervix, passes under the uterine artery. A clamp, tie or cut meant for those vessels can catch the ureter, so the surgeon identifies it before dividing them. A memory aid: water (the ureter) runs under the bridge (the uterine artery).

For some pelvic and abdominal operations, the urologist first places ureteral catheters or stentsstentstentA small tube, often of metal mesh, placed inside a vessel or duct to hold it open.Full entry Close, so the surgeon can feel the ureters and is less likely to cut or tie them.

The bladder in lower abdominal surgery and cesarean birth

The bladder lies right behind the lower abdominal wall, and it rises when it is full.

• Before a cesareancesareansih-ZAIR-ee-unRelating to the birth of a baby through a surgical cut in the mother's abdomen and uterus.Full entry Close, an indwelling urinary catheterindwelling urinary catheterin-DWEL-ing YUR-ih-nair-ee KATH-uh-terA tube passed through the urethra into the bladder and left in place to drain urine into a bag.Full entry Close is put in to drain it.
• When the peritoneumperitoneumpair-ih-toh-NEE-umThe thin membrane that lines the belly cavity and covers most of the organs inside it.peri- aroundton stretched-eum a structureFull entry Close is opened, the surgeon lifts it and feels it first to make sure no bowel, omentum or bladder is caught in the cut.
• In a cesarean, the surgeon divides the bladder flap, the fold of peritoneum between the uterus and the bladder, and a bladder retractorretractorrih-TRAK-terA surgical instrument that holds back tissue or organs so the surgeon can see and reach the operative site.Full entry Close (a DeLee or a Balfour bladder blade) holds the bladder down, out of the way, before the uterus is opened.

The inguinal canal in hernia repair

In an open groin herniaherniaHER-nee-uhA bulge of an organ or tissue through a weak spot in the muscle or tissue wall that normally holds it in.Full entry Close repair in a male, the spermatic cord lies in the field. The surgeon frees it and loops a small Penrose drain around the testicular vessels and ductus deferens to lift it gently out of the way. In a female, the canal holds the round ligament instead. Chapter 32 teaches the repairs.

Through the urethra

The urethraurethrayoo-REE-thruhThe tube that carries urine from the bladder out of the body.Full entry Close is the doorway for the urologist's scopes. Cystoscopy looks into the bladder, a ureteroscope goes on up the ureter, and a resectoscope cuts away prostateprostatePROS-taytA walnut-sized gland below the bladder in males that surrounds the urethra and makes part of the fluid in semen.Full entry Close tissue in a TURPtransurethral resection of the prostatetrans-yoo-REE-thrul rih-SEK-shun of the PROS-taytSurgery that removes part of the prostate gland with an instrument passed up through the urethra.trans- throughurethr/o urethra-al relating toresection cutting outFull entry Close. A TURP is done with the patient in the lithotomylithotomylih-THOT-uh-meeA position lying on the back with the hips and knees bent and the legs raised and spread apart, often in stirrups.lith/o stone-tomy cutting intoFull entry Close position, and chapter 34 teaches these cases.

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