Anatomy Reproductive System PDF

o **Reproductive System Overview** - **The reproductive system is responsible for producing, storing, nourishing, and transporting reproductive cells (gametes).** - **Structures include gonads (reproductive organs producing gametes and hormones), ducts (receive and transport gametes),...

o **Reproductive System Overview** - **The reproductive system is responsible for producing, storing, nourishing, and transporting reproductive cells (gametes).** - **Structures include gonads (reproductive organs producing gametes and hormones), ducts (receive and transport gametes), accessory glands (secrete fluids into ducts), and external genitalia.** **Male Reproductive System** - **Gametes (sperm): Produced in the testes. Testes also produce androgens (primarily testosterone). Sperm combines with secretions from accessory glands to form semen.** - **Ducts: Sperm travels through the epididymis, ductus deferens, ejaculatory duct, and urethra.** - **Accessory organs: Seminal glands, prostate gland, and bulbo-urethral glands secrete fluids into the ejaculatory ducts and urethra.** - **External genitalia: Scrotum and penis.** **Male Reproductive System: Testes and Scrotum** - **Testes are about 5 cm long, 3 cm wide, and 2.5 cm thick.** - **Held outside the body in the scrotum.** - **Scrotum is divided into two chambers, each holding a testis.** - **Dartos and cremaster muscles help regulate testis temperature.** - **Each testis has a fibrous capsule called the tunica albuginea.** **Male Reproductive System: Internal Structure of Testes** - **Collagen fibers extending into the testis, forming septa.** - **Testis divided into about 250 lobules.** - **Seminiferous tubules are tightly coiled within each lobule; site of spermatogenesis (sperm production).** - **Tubules also contain nurse cells (Sertoli cells) that nourish developing sperm.** - **Sperm passes through rete testis into efferent ductules to epididymis.** **Male Reproductive System: Interstitial Cells** - **Also called Leydig cells.** - **Located in spaces between seminiferous tubules.** - **Produce male sex hormones (androgens), with testosterone as the most important.** **Male Reproductive System: Epididymis** - **Coiled tube attached to the posterior portion of the testis.** - **Adjusts fluid composition produced by seminiferous tubules.** - **Recycles damaged spermatozoa.** - **Stores and protects maturing spermatozoa.** - **Takes about two weeks for sperm to travel through and complete maturation.** - **Sperm in epididymis is physically mature but immobile.** - **Substance secreted by epididymis prevents premature capacitation, or full sperm activation.** **Male Reproductive System: Ductus Deferens** - **Also called the vas deferens.** - **Spermatozoa and fluid propelled along it by peristalsis.** - **Passes through the inguinal canal into the abdominal cavity within the spermatic cord.** - **Passes laterally to the urinary bladder.** - **Curves down past ureters toward the prostate gland.** - **Expanded distal portion called the ampulla.** - **Sperm can be stored here up to several months.** **Male Reproductive System: Ejaculatory Duct** - **Short passageway formed where ampulla of ductus deferens joins with duct of seminal gland.** - **Passes through the wall of the prostate gland.** - **Empties into the urethra.** **Male Reproductive System: Urethra** - **Extends from urinary bladder to tip of penis.** - **18-20 cm long.** - **Passageway for both urinary and reproductive systems (urine and semen).** **Male Reproductive System: Accessory Glands** - **Include seminal glands, prostate gland, and bulbo-urethral glands.** - **Produce fluid component of semen.** - **Activate spermatozoa.** - **Provide nutrients for motility.** - **Generate peristaltic contractions to propel sperm and semen.** - **Produce buffers to counteract acidic environment of urethra and vagina.** **Male Reproductive System: Seminal Glands** - **Also called seminal vesicles.** - **Contribute 60% of semen fluid.** - **Secretion is slightly alkaline to neutralize acids.** - **Secretions contain fructose, prostaglandins, and fibrinogen.** **Male Reproductive System: Prostate Gland** - **Small, round, muscular organ.** - **Surrounds urethra as it leaves the urinary bladder.** - **Produces prostatic fluid (slightly acidic). -Makes up about 20-30% of semen.** - **Contains seminalplasmin (protein with antibiotic properties).** - **Peristaltic contractions help propel secretions into urethra.** **Male Reproductive System: Bulbo-Urethral Glands** - **Also called Cowper\'s glands.** - **Paired glands located at the base of the penis.** - **Contribute less than 5% of semen.** - **Secrete thick alkaline mucus.** - **Helps neutralize urinary acids.** - **Lubricates the glans penis.** **Male Reproductive System: Semen** - **Fluid containing sperm and secretions of accessory glands.** - **Typical ejaculation expels 2-5 mL of semen, called ejaculate.** - **Contains spermatozoa (normal sperm count 20-100 million/mL).** - **Seminal fluid (fluid component of semen).** - **Enzymes (protease for dissolving mucus, seminalplasmin to kill bacteria, enzymes for liquefying semen).** **Male Reproductive System: Penis** - **Tubular organ containing distal portion of urethra.** - **Introduces semen to vagina during intercourse.** - **Also conducts urine to the exterior through urethra.** - **Three main regions: Root, Body, and Glans.** - **Prepuce (foreskin)-fold of skin over glans, often removed.** **Male Reproductive System: Prepuce and Circumcision** - **Prepuce (foreskin)-fold of skin over glans penis.** - **Preputial glands secrete smegma.** - **Can be a nutrient source for bacteria.** - **Circumcision is the surgical removal of prepuce.** - **Generally performed shortly after birth.** - **Lowers risks of UTI, penile cancer, and HIV infection.** - **Still controversial when not done for religious reasons.** **Male Reproductive System: Erectile Tissue of the Penis** - **Maze of vascular channels with incomplete partitions of elastic connective tissue and smooth muscle.** - **Corpus spongiosum surrounds urethra.** - **In resting state, little blood flow, arterial branches restricted.** - **During erection, parasympathetic neurons release nitric oxide (NO), smooth muscles in arterial walls relax, vessels dilate, and channels fill with blood.** **Male Reproductive System: Male Reproductive Hormones** - **GnRH (gonadotropin-releasing hormone) secreted by hypothalamus triggers release of FSH and LH from anterior pituitary.** - **FSH targets cells to trigger spermatogenesis.** - **LH causes interstitial cells to secrete testosterone.** - **Testosterone stimulates differentiation of male reproductive tract and affects CNS development.** - **Initiates sexual maturity and development of secondary sex characteristics.** - **Negative feedback controls levels of testosterone.** **Female Reproductive System Overview** - **Gametes (oocytes) are produced in the ovaries.** - **Travel through ducts (uterine tube, uterus, vagina).** - **Accessory glands include the greater vestibular gland.** - **External genitalia include the labia minora, labia majora, and clitoris** **Female Reproductive System: Ovaries** - **Paired, small, lumpy, almond-shaped organs.** - **Each is \~5 cm long, 2.5 cm wide, 8 mm thick.** - **Located near lateral walls of pelvic cavity.** - **Stabilized by the broad ligament, ovarian ligament, and suspensory ligament.** - **Suspensory ligament contains ovarian artery and ovarian vein.** **Female Reproductive System: Ovarian Function** - **Produce female gametes (oocytes).** - **Secrete female sex hormones (estrogens and progesterone).** - **Involved in feedback control of FSH.** **Female Reproductive System: Oogenesis** - **Process of ovum production.** - **Begins before birth, ends at menopause.** - **Occurs each month as part of the ovarian cycle.** - **Oogonia (female reproductive stem cells) complete mitosis before birth, producing primary oocytes.** - **Primary oocytes begin meiosis between the third and seventh month of fetal development and pause in prophase I until puberty.** **Female Reproductive System: Ovarian Cycle Overview** - **28-day cycle divided into follicular and luteal phases, separated by ovulation.** - **Follicular phase (preovulatory phase) takes about 14 days.** - **Luteal phase (postovulatory phase) takes about 14 days.** **Female Reproductive System: Ovarian Cycle- Follicular Phase** - **FSH stimulates follicle development.** - **A tertiary follicle becomes dominant by day 5 (mature graafian follicle).** - **Expanded central chamber of follicle (antrum).** - **LH increases, prompting a primary oocyte to complete meiosis I, producing a secondary oocyte and a polar body.** - **Secondary oocyte and surrounding follicular cells (corona radiata) float within antrum by day 14.** **Female Reproductive System: Ovarian Cycle- Ovulation** - **Tertiary follicle releases secondary oocyte.** - **Follicle wall ruptures, releasing secondary oocyte and follicular contents into pelvic cavity.** - **Follicular fluid is sticky, keeping the corona radiata attached to the ovary briefly.** - **Oocyte swept into uterine tube.** **Female Reproductive System: Ovarian Cycle- Luteal Phase** - **Empty follicle collapses, forming corpus luteum, an endocrine structure.** - **Corpus luteum secretes progesterone.** - **Without fertilization, corpus luteum degenerates to corpus albicans.** - **Marks end of full ovarian cycle.** - **FSH rises to initiate another ovarian cycle.** **Female Reproductive System: Uterine Tubes** - **Also called fallopian tubes or oviducts.** - **Roughly 13 cm long.** - **Expanded end closest to ovary is called infundibulum.** - **Fingerlike projections of infundibulum are fimbriae.** - **Movements of fimbriae and cilia help propel oocyte into uterine tube.** - **Walls of tube move oocytes toward uterus using ciliary movement and peristalsis.** **Female Reproductive System: Oocyte Passage in the Uterine Tube** - **Normally takes 3-4 days for oocyte to reach uterus.** - **Oocytes must meet sperm within first 12-24 hours for fertilization.** - **Unfertilized oocytes degenerate and are expelled with menstrual cycle.** **Female Reproductive System: Uterus** - **Pear-shaped, muscular organ.** - **Held in place by ligaments and mesenteries.** - **Bends anteriorly over the urinary bladder.** - **Two regions: Body and Cervix.** - **Functions: Protect, nourish, and remove wastes for developing embryo/fetus and contracts to eject fetus at birth.** **Female Reproductive System: Uterus- Regions** - **Body (largest region), fundus (rounded portion superior to uterine tubes attachment), and isthmus (narrowed area of body at inferior end).** - **Cervix (projects short distance into vagina with external os as opening into vagina and cervical canal opening into uterine cavity at internal os)** **Female Reproductive System: Uterine Wall** - **Inner endometrium (superficial functional zone of epithelial lining that undergoes monthly cyclical changes, deeper basilar zone that remains intact).** - **Muscular myometrium (muscle layer contracts during labor/delivery)** - **Outer perimetrium (layer of visceral peritoneum).** **Female Reproductive System: Uterine Cycle** - **Repeated series of changes in endometrial structure, also called menstrual cycle.** - **Begins at puberty (menarche).** - **Continues until menopause, but interrupted by illness, stress, starvation, pregnancy.** - **Averages \~28 days.** **Female Reproductive System: Uterine Cycle- Menses** - **Period marked by degeneration of the functional zone of the endometrium.** - **Triggered by a drop in progesterone/estrogen as corpus luteum disintegrates.** - **Endometrial arteries constrict, reducing blood flow.** - **Secretory glands and epithelial cells die.** - **Process of shedding blood and dead cells through vagina.** - **Usually lasts 1-7 days; blood loss about 35-50 mL.** **Female Reproductive System: Uterine Cycle- Proliferative Phase** - **Begins at completion of menses.** - **Stimulated by increasing estrogen levels.** - **Endometrial epithelial layer repairs and multiplies within the deeper portion (basilar zone).** - **Small arteries regrow.** - **New uterine glands forms.** - **Functional zone becomes several mm thick.** **Female Reproductive System: Uterine Cycle- Secretory Phase** - **Begins at ovulation.** - **Uterine glands enlarge and prepare endometrium for a developing embryo.** - **Stimulated by progesterone and estrogens from corpus luteum.** - **As corpus luteum degenerates, uterine cycle ends, and menses resumes.** **Female Reproductive System: The Vagina** - **Elastic, muscular, distensible tube extending between uterus and exterior.** - **Parallel and anterior to rectum; posterior to urethra.** - **Opens into vestibule.** - **Fornix: shallow recess surrounding base of cervix.** - **Hymen: epithelial fold partially blocking vaginal entrance** **Female Reproductive System: The Vagina (cont.)** - **Bulbospongiosus muscles extend along side of vaginal entrance.** - **Cover vestibular bulbs on either side of vaginal entrance.** **Female Reproductive System: Functions of the Vagina** - **Passageway for elimination of menstrual fluid.** - **Receives penis and holds semen during intercourse.** - **Forms lower portion of birth canal.** **Female Reproductive System: External Genitalia** - **Area that contains external genitalia is vulva or pudendum.** - **Vagina opens into vestibule.** - **Urethral opening is anterior to vaginal opening.** - **Clitoris, erectile tissue, is anterior to urethral opening.** - **Vestibule bound by labia minora (smooth hairless skin covering clitoris with prepuce or hood).** - **Lesser and greater vestibular glands moisten and lubricate vaginal entrance.** - **Mons pubis and labia majora form outer area that protects vestibule.** **Female Reproductive System: Comparable Male and Female Structures** - **Clitoris derived from same embryonic tissue as penis.** - **Contains erectile tissue comparable to corpora cavernosa of penis.** - **Vestibular bulbs, erectile tissue on sides of vestibule, comparable to corpus spongiosum.** - **Greater vestibular glands resemble bulbo-urethral glands.** **Female Reproductive System: The Mammary Glands** - **Function in lactation (milk production).** - **Controlled by hormones of the reproductive system and placenta.** - **Located within subcutaneous tissue of pectoral fat pad beneath skin of breasts.** - **Suspensory ligaments of the breast are bands of connective tissue forming partitions within breast.** **Female Reproductive System: Flow of Milk** - **Milk glands found in lobules.** - **Ducts carrying milk leave lobules and merge into a single lactiferous duct.** - **Milk drains into lactiferous sinus that opens onto body surface through nipple.** - **About 15-20 lactiferous sinuses open onto surface of each nipple.** - **Areola is brownish skin surrounding nipple.** **Female Reproductive System: Hormones** - **Anterior pituitary hormones govern ovarian cycles.** - **Regulate secretions of ovarian hormones.** - **Provide feedback to hypothalamus.** - **Ovarian hormones govern uterine cycles and provide feedback to hypothalamus and pituitary.** **Female Reproductive System: Hormones and the Follicular Phase** - **Begins with increased FSH from anterior pituitary** - **FSH stimulates follicular cells, which secrete estrogens, most importantly estradiol.** - **Estrogen stimulates bone and muscle growth, establishes and maintains secondary sex characteristics.** - **Increases CNS activity (including sexual drive).** - **Maintains accessory reproductive glands and organs.** - **Initiates repair and growth of endometrium.** **Female Reproductive System: Early and Late Follicular Phase** - **Early follicular phase: estrogen and inhibin levels low.** - **Late follicular phase: rapid increase in estrogens and inhibin, which leads to increased FSH and LH.** - **Peak in estrogen levels about day 14.** - **LH surge triggers ovulation.** **Female Reproductive System: Hormones and the Luteal Phase** - **Corpus luteum develops and secretes progesterone.** - **Prepares endometrium for implantation of embryo.** - **If pregnancy doesn\'t occur, corpus luteum degenerates into corpus albicans.** - **Progesterone and estrogen levels drop after \~12 days of ovulation.** - **Removes inhibition of GnRH.** - **GnRH stimulates FSH production, and a new ovarian cycle begins.** **Female Reproductive System: Regulation of Female Reproduction (diagram)** - **Diagram showing the regulation of female reproduction in a flow chart style that depicts the interactions between the hypothalamus, anterior pituitary, and ovaries.** **Female Reproductive System, Checkpoint Questions** - **Questions about female reproductive structures, affects of blocked uterine tubes, benefit of vaginal pH, and layer of the uterine wall shed during menstruation.** **Female Reproductive System, Checkpoint Questions (cont.)** - **Questions about blockage of a single lactiferous sinus, changes in ovarian cycle with LH surge, effect of blocked progesterone receptors in uterus, and event in uterine cycle when estrogen/progesterone levels decline.** **Menopause** - **Time when ovulation and menstruation cease.** - **Typically occurs between ages 45-55.** - **Perimenopause is the time period before menstrual cycle becomes irregular.** - **Accompanied by a decline in estrogen and progesterone.** - **Due to a shortage of follicles that can respond to FSH.** - **With no inhibin produced by follicles, levels of FSH remain high.** - **Reduces size of uterus and breasts; vaginal and urethral walls thin; linked to osteoporosis.** **Overview Table of Reproductive Hormones** - **Table showing hormones, their sources, regulation via positive/negative feedback, and primary effects.** **Urinary System Functions** - **The urinary system\'s major functions include excreting organic wastes like urea from bodily fluids** - **It eliminates these wastes into the external environment** - **It regulates the volume and solute concentration of blood** **Urinary System Organs** - **The urinary system consists of two kidneys** - **Kidneys produce urine, which passes through the urinary tract** - **The urinary tract includes:** - **Two ureters, which carry urine from the kidneys to the bladder** - **The urinary bladder, which stores urine** - **The urethra, which carries urine from the bladder to the exterior of the body** - **Urination, or micturition, is the process of eliminating urine** **Kidney Location and Positioning** - **Kidneys are located on either side of the vertebral column, between the last thoracic and third lumbar vertebrae** - **The right kidney is slightly lower than the left** - **Kidneys are somewhat displaced by the liver** - **They are positioned behind the peritoneum (retroperitoneal)** - **Adrenal glands sit on the superior surface of each kidney** - **Kidneys are held in place by the overlying peritoneum, contact with adjacent organs, and supportive connective tissue** - **Fibrous capsule surrounds the kidney, containing adipose tissue** - **Damage to the suspensory fibers of the outer layer can cause kidney displacement or a floating kidney** **Kidney Anatomy (Superficial)** - **Kidneys are bean-shaped, roughly 10 cm long, 5.5 cm wide, and 3 cm thick** - **The indentation on one side is the hilum** - **The hilum is where the renal artery and renal nerves enter, and the renal veins and ureters exit** - **Fibrous capsule covers the outer surface** - **The fibrous capsule contains the renal sinus, an internal cavity** **Kidney Anatomy (Sectional)** - **Renal cortex: the outer layer, in contact with the fibrous capsule, and projects into the medulla as renal columns** - **Renal medulla: the inner layer, containing 6-18 cone-shaped renal pyramids** - **Renal papilla: the tip of each renal pyramid, projecting into the renal sinus** - **Kidney Lobe: includes a renal pyramid, overlying cortex, and renal columns** - **Urine production begins in nephrons in the cortex of each kidney lobe** - **There are approximately 1.25 million nephrons in each kidney** - **Nephron ducts carry urine into a cup-like structure called a minor calyx** - **4-5 minor calyces merge to form a major calyx** - **2-3 major calyces form a funnel-shaped chamber called the renal pelvis** - **Renal pelvis connects to the ureter** **Kidney Blood Supply** - **Kidneys receive 20-25% of total cardiac output (about 1200 mL of blood per minute)** - **Blood flow begins with the renal artery** - **Blood travels through interlobar arteries, arcuate arteries, cortical radiate arteries, afferent arterioles, glomerular capillaries, efferent arterioles, peritubular capillaries, cortical radiate veins, arcuate veins, interlobar veins, and finally exits through the renal veins** **Blood Flow from Peritubular Capillaries** - **Blood from peritubular capillaries flows in two ways:** - **In cortical nephrons, blood flows directly into cortical radiate veins** - **In juxtamedullary nephrons, blood travels through vasa recta, which run parallel to nephron loops and flow into cortical radiate veins** **Nephron Structure** - **The nephron is the basic functional unit of the kidney** - **It consists of two main parts: the renal corpuscle and the renal tubule** **Renal Corpuscle** - **Spherical structure containing a glomerular (Bowman\'s) capsule and a network of capillaries (glomerulus)** - **Blood flows into the glomerulus via the afferent arteriole and leaves via the efferent arteriole** - **The process of forcing fluid and dissolved solutes from the glomerular capillaries into the capsular space is called filtration** - **It produces a solution called filtrate** **Renal Tubule** - **Filtrate flows through the following segments in order:** - **Proximal convoluted tubule (PCT)** - **Nephron (loop of Henle)** - **Distal convoluted tubule (DCT)** - **The filtrate is called tubular fluid at this point** - **The tubular fluid flows into a collecting duct** - **Collecting ducts lead to papillary ducts and minor calyces** - **Fluid at this stage is called urine** **Functions of the Nephron** - **The renal corpuscle produces filtrate via a passive process.** - **The filtrate includes valuable nutrients, ions, and water.** - **The tubules reabsorb useful molecules, ions, and water from the filtrate back into the blood. More than 90% of the water is reabsorbed** - **Any waste products missed during filtration are secreted** **Glomerular Capsule** - **Forms the outer wall of the renal corpuscle.** - **Encloses glomerular capillaries.** - **Composed of two layers of cells: Outer (parietal) and Inner (visceral) layer.** - **Visceral layer cells are called podocytes, which have foot processes (pedicels) that wrap around capillaries.** **Metabolic Wastes in Urine** - **Urea is the most abundant organic waste, formed from the breakdown of amino acids in skeletal muscle tissue** - **Creatinine is generated from skeletal muscle creatine phosphate breakdown** - **Uric acid is derived from RNA breakdown and recycling** **Ureters** - **Paired muscular tubes that transport urine from the kidneys to the urinary bladder** - **Begins at the funnel-shaped renal pelvis.** - **Ends at the posteroinferior bladder wall.** - **Features slit-like ureteral openings to prevent urine backflow.** - **Wall contains 3 layers: inner transitional epithelium, middle smooth muscle layer (peristalsis), and outer connective tissue.** **Kidney Stones** - **Also called calculi, kidney stones are solid substances consisting of calcium deposits, magnesium salts, or uric acid crystals.** - **Can form in the kidney, ureter, or urinary bladder.** - **Cause a painful condition known as nephrolithiasis** - **Can block urine flow, potentially reducing or preventing filtration.** **Urinary Bladder** - **Stores urine.** - **Size varies with distension and can hold up to 1 liter.** - **Held in place by peritoneal folds (umbilical ligaments) and connective tissue.** - **In males, it's located between the rectum and pubic symphysis.** - **In females, it\'s inferior to the uterus and anterior to the vagina.** **Internal Urinary Bladder Anatomy** - **Base includes the trigone, formed by two ureteral openings and an urethral entrance.** - **Surrounding the urethral entrance is the neck of the bladder, also possessing an involuntary internal urethral sphincter.** - **The bladder wall contains transitional epithelium and layers of smooth muscle (detrusor muscle), which contracts to expel urine into the urethra.** **Urethra** - **Extends from the urinary bladder neck to the exterior of the body** - **In males, extends approximately 18-20 cm and opens at the tip of the penis.** - **In females, it's shorter, about 2.5-3.0 cm, and opens near the anterior wall of the vagina.** - **A circular band of skeletal muscle (external urethral sphincter) surrounds the urethra, providing voluntary control of urination.** **The Collecting System** - **Several collecting ducts merge to form papillary ducts** - **Papillary ducts empty into minor calyces** - **Functions of the collecting system include:** - **Transporting tubular fluid from the nephron to renal pelvis** - **Adjusting final fluid composition** - **Determining final osmotic concentration of urine** **Juxtaglomerular Complex** - **A combination of closely associated cells in the distal convoluted tubule and afferent arteriole** - **The macula densa is a region of clustered cells in the DCT, and juxtamedullary cells form part of the complex** - **Unusual smooth muscle fibers are present in the afferent arteriole wall, important in regulating blood volume and blood pressure** - **Secretion of erythropoietin and renin are integral kidney functions** **Proximal Convoluted Tubule (PCT)** - **The first segment of the renal tubule** - **The majority of reabsorption occurs here.** - **This is where cells lining this tubule reabsorb organic nutrients, ions, and blood plasma proteins from the tubular fluid.** - **Substances are moved from the PCT tubule to the interstitial fluid or peritubular fluid, and re-enter the blood by osmosis.** - **The PCT reduces tubular fluid volume.**