Lecture 14 Reproductive System and Urinary System PDF

Reproduct ive System Urinary System Major Functions of the Urinary System 1. ​Excretion of organic wastes, such as urea, from body fluids 2. ​Elimination of these wastes into the external environment 3. ​Homeostatic regulation of volume and solute concentration of blood Organs of the Urinary Syst...

Reproduct ive System Urinary System Major Functions of the Urinary System 1. ​Excretion of organic wastes, such as urea, from body fluids 2. ​Elimination of these wastes into the external environment 3. ​Homeostatic regulation of volume and solute concentration of blood Organs of the Urinary System Two kidneys Produce urine that flows through urinary tract Urinary tract includes: Two ureters that transport urine from kidneys to bladder Urinary bladder stores urine Urethra transports urine from urinary bladder to exterior of body Elimination of urine is process called urination or micturition The Organs of the Urinary System. Organs of the Urinary System Kidney Produces urine Ureter Transports urine toward the urinary bladder Urinary bladder Temporarily stores urine before urination Urethra Conducts urine to exterior; in males, it also transports semen Anterior view Homeostatic Functions of the Urinary System In addition to removing organic wastes, urinary system also: Regulates blood volume and blood pressure Regulates concentration of plasma ions, such as sodium, potassium, chloride, and calcium Helps stabilize blood pH Conserves valuable nutrients like glucose and amino acids  Bozeman: Urinary System https://www.youtube.com/watch?v=H2VkW9L5QSU  Checkpoint Name the three major functions of the urinary system. Identify the organs of the urinary system.  Located on either side of vertebral column Between last thoracic and 3rd lumbar vertebrae Right kidney sits slightly lower Kidney Location than left Displaced somewhat by the liver Situated behind (dorsal to) peritoneum Position called retroperitoneal Adrenal gland located on superior surface of each kidney  Diaphragm 11th and Adrenal gland 12th ribs Left kidney Lumbar (L1) vertebra Right kidney Ureter Renal artery Inferior and vein vena cava The Position of the Kidneys. Iliac crest Aorta Urinary bladder Urethra This posterior a view of the trunk shows the positions of the kidneys and other organs of the urinary system. Kidney Positioning Kidneys held in place by: Overlying peritoneum Contact with adjacent organs Supportive connective tissue Fibrous capsule covers each kidney Capsule surrounded by adipose tissue Outer fibrous layer anchors to surrounding structures Damage to suspensory fibers of outer layer may result in displaced or floating kidney The Position of the Kidneys. Parietal Renal Renal peritoneum Stomach vein artery Aorta Hilum of Pancreas kidney Ureter Spleen Left kidney Vertebra Fibrous capsule Adipose tissue Inferior vena cava A superior b view of a section at the level indicated in part (a) shows the kidney’s retroperitoneal position. Superficial Anatomy of the Kidneys About 10 cm long, 5.5 cm wide, 3 cm Kidneys thick Indentation on one side is the hilum are bean Point of entry for renal artery and renal nerves shaped Point of exit for renal veins and ureter Fibrous Covers outer surface capsule Lines renal sinus, an internal cavity  Renal cortex is outer layer In contact with fibrous capsule Projects into medulla as renal columns Sectional Renal medulla is inner layer Contains 6–18 cone-shaped Anatomy of the renal pyramids Tip of each pyramid called renal Kidney papilla Projects into renal sinus Kidney lobe Contains pyramid, overlying cortex, and renal columns Sectional Anatomy of the Kidney (cont.) Urine production begins in nephrons in cortex of each kidney lobe About 1.25 million nephrons in each kidney Ducts within renal papilla drain urine into a cup-like structure called the minor calyx 4–5 minor calyces merge to form major calyx 2–3 major calyces combine to form large funnel-shaped chamber called the renal pelvis Renal pelvis connected to the ureter The Structure of the Kidney. Renal cortex Renal medulla Renal cortex Renal pyramids Renal medulla Renal Renal sinus sinus Major calyx Hilum Renal Major calyx pelvis Minor calyx Renal Hilum Renal pyramid pelvis Minor Renal Kidney lobe Ureter calyx papilla (dashed lines) Renal Renal columns Renal papilla columns Ureter Fibrous capsule Fibrous capsule a A diagrammatic view of a frontal section through the left kidney b A frontal section through the left kidney Blood Supply to the Kidney Kidneys receive 20–25 percent of total cardiac output (about 1200 mL of blood each minute) Blood flow starts with renal artery → Interlobar arteries (run between renal pyramids) → Arcuate arteries (along cortex-medulla boundary) → Cortical radiate arteries (or interlobular arteries) → Afferent arterioles (delivering blood to individual nephrons) → Glomerular capillaries → Efferent arterioles → Peritubular capillaries (surrounding nephron) → Cortical radiate veins (or interlobular veins) → Arcuate veins → Interlobar veins → Exits kidney by the renal veins The Blood Supply to the Kidneys. Medulla Adrenal artery Renal Cortical radiate artery veins Renal vein Cortical radiate arteries Interlobar arteries Interlobar Arcuate veins veins Arcuate arteries Thisasectional view of a kidney shows the major arteries and veins. Blood Flow from Peritubular Capillaries Blood from the peritubular capillaries follows two possible paths 1. In cortical nephrons (located almost entirely within renal cortex): Blood flows from peritubular capillaries directly into cortical radiate veins 2. In juxtamedullary nephrons: Peritubular capillaries are connected to the vasa recta Vasa recta run parallel to long nephron loops deep into the medulla Blood flows from vasa recta into cortical radiate veins The Blood Supply to the Kidneys. Nephrons Cortex Afferent arterioles Medulla This b enlarged view shows the circulation in a single kidney lobe.  Nephrons Efferent arteriole Cortex Afferent Peritubular arteriole capillaries Renal Afferent corpuscle arterioles Peritubular capillaries Collecting duct Medulla Nephron loop b This enlarged view c Further enlargement shows the shows the circulation circulation to a cortical nephron. in a single kidney lobe. Proximal Peritubular convoluted capillaries tubule (PCT) The Blood Supply to the Kidneys. Efferent Distal arteriole convoluted Glomerulus tubule (DCT) Afferent arteriole Vasa recta Collecting duct Nephron loop d Further enlargement shows the circulation to a juxtamedullary nephron.  Basic functional unit of the kidney The Nephron Consists of two main parts ​ enal R ​ enal R corpuscle tubule The Structure of the Kidney. Renal corpuscle Proximal convoluted tubule Distal convoluted tubule Collecting duct Nephron Papillary duct loop c enlarged view showing An the location and general structure of a nephron  Renal Corpuscle Spherical structure consisting of: Cup-shaped glomerular (Bowman’s) capsule containing: Network of capillaries known as glomerulus Blood flows into glomerulus from afferent arteriole and leaves by efferent arteriole Fluid and dissolved solutes forced out of glomerular capillaries and into surrounding capsular space Process called filtration Produces solution called filtrate Renal Tubule Filtrate flows into segments of renal tubule in order: Proximal convoluted tubule (PCT) Nephron loop, or loop of Henle Distal convoluted tubule (DCT) Filtrate at end called tubular fluid Each nephron empties into collecting duct Beginning of collecting system Collecting ducts drain into papillary ducts and into minor calyces Fluid at this point called urine  NEPHRON COLLECTING SYSTEM Proximal Convoluted Tubule Distal Convoluted Tubule Nephron and the Collecting System. Renal Corpuscle Renal tubule Efferent arteriole Collecting Duct Afferent arteriole Glomerulus Loop begins Loop ends Nephron Loop Thick Descending limb ascending limb Ascending limb Thin descending limb Papillary Duct KEY Flow of tubular fluid Solute reabsorption Minor Filtrate or secretion calyx Water reabsorption Variable solute Variable water reabsorption reabsorption or secretion © 2017 Pearson Education, Inc. Functions of the Nephron Corpuscle Produces filtrate by a passive process Filtrate includes valuable nutrients, ions, and water Tubules 1. Reabsorb useful molecules and ions from filtrate back into blood 2. Reabsorb >90 percent of water back into blood 3. Secrete any waste products missed by filtration process  Forms outer wall of renal corpuscle Encloses the glomerular capillaries The Glomerular Formed by two layers of cells Capsule separated by capsular space Outer layer, or capsular epithelium, forms wall of corpuscle Inner layer, or visceral epithelium, encloses glomerular capillaries Cells in this layer are called podocytes Have foot processes called pedicels that wrap around capillaries Renal Corpuscle. Glomerular capillary Glomerular Capsule Parietal epithelium Efferent arteriole Capsular space Visceral epithelium Juxtaglomerular (podocyte) Complex Macula densa Juxtaglomerular cells Proximal convoluted Distal convoluted tubule tubule Afferent arteriole a sectional view illustrates This the important structural features of a renal corpuscle. Filtration Membrane Nucleus Capillary Podocyte endothelium Podocyte Pedicels Pores Basement membrane Filtration slits Supporting cell RBC This cross section b Pedicels through a segment of the glomerulus A podocyte SEM × 2300 shows the Capsular space components of the This c colorized photomicrograph shows the filtration membrane Capsular glomerular surface, including individual of the nephron. epithelium podocytes and their processes. The Renal Corpuscle. Glomerular capillary Glomerular Capsule Parietal epithelium Efferent arteriole Capsular space Visceral epithelium Juxtaglomerular (podocyte) Complex Macula densa Juxtaglomerular cells Proximal convoluted Distal convoluted tubule tubule Afferent arteriole This a sectional view illustrates the important structural features of a renal corpuscle.  First segment of renal tubule The Majority of reabsorption occurs here Proximal Cells lining PCT reabsorb organic nutrients, plasma proteins, and ions Convolut from tubular fluid Substances are moved from tubule ed Tubule to interstitial fluid, or peritubular fluid Materials re-enter the blood Water follows by osmosis Reduces volume of tubular fluid The Nephron Loop Composed of descending limb and ascending limb Fluid in descending limb flows toward renal pelvis Epithelium permeable to water, not solutes Tubule makes 180-degree turn Fluid in ascending limb flows toward renal cortex Epithelium not permeable to water Actively transports sodium and chloride out of tubule Result is unusually high solute concentration in peritubular fluid of renal medulla Water from descending limb moves out by osmosis The Distal Convoluted Tubule Passes adjacent to afferent and efferent arterioles Site for three vital processes 1. Active secretion of ions, acids, drugs, and toxins 2. Selective reabsorption of sodium 3. Selective reabsorption of water  Combination of closely associated cells in the DCT and afferent arteriole Macula densa The Region of clustered cells in DCT closest to the glomerulus Juxtaglomerular cells Juxtaglomerular Unusual smooth muscle fibers in wall of afferent arteriole Complex Involved in regulation of blood volume and blood pressure Through secretion of erythropoietin and renin The Renal Corpuscle. Glomerular capillary Glomerular Capsule Parietal epithelium Efferent arteriole Capsular space Visceral epithelium Juxtaglomerular (podocyte) Complex Macula densa Juxtaglomerular cells Proximal convoluted Distal convoluted tubule tubule Afferent arteriole This a sectional view illustrates the important structural features of a renal corpuscle. The Collecting System Many DCTs empty into one collecting duct Several collecting ducts merge to form a papillary duct Papillary duct empties into minor calyx Functions of the collecting system Transports tubular fluid from nephron to renal pelvis Adjusts final fluid composition Determines final osmotic concentration of urine Determines final volume of urine © 2017 Pearson Education, Inc. Metabolic Wastes in Urine Must be excreted to maintain homeostasis Eliminated dissolved in urine, which requires water loss 1. ​Urea Most abundant organic waste Formed during breakdown of amino acids 2. ​Creatinine Generated in skeletal muscle tissue from breakdown of creatine phosphate 3. ​Uric acid Formed from breakdown and recycling of RNA The Ureters Paired muscular tubes conduct urine from kidneys to urinary bladder Each ureter begins at funnel-shaped renal pelvis Ends at posterior, slightly inferior bladder wall Slit-like ureteral openings prevent urine backflow Ureter wall contains three layers 1. Inner layer of transitional epithelium 2. Middle layer of smooth muscle that moves urine through tube by peristalsis 3. Outer connective tissue layer (continuous with renal capsule) Kidney Stones Also called calculi Solid substances made of calcium deposits, magnesium salts, or crystals of uric acid Can form within kidney, ureter, or urinary bladder Results in painful condition called nephrolithiasis Obstruct flow of urine May reduce or prevent filtration The Urinary Bladder Location and Size Hollow muscular organ that stores urine Size varies with amount of distention When full, can contain up to a liter of urine Held in place in pelvic cavity by peritoneal folds (umbilical ligaments) and connective tissue In males: Base lies between rectum and pubic symphysis In females: Sits inferior to the uterus and anterior to the vagina Internal Anatomy of the Urinary Bladder Base has triangular area called trigone, formed by: Two ureteral openings Urethral entrance Area surrounding urethral entrance is neck of bladder Contains involuntary internal urethral sphincter Bladder wall contains: Transitional epithelium Layers of smooth muscle called detrusor muscle Contraction of muscle expels contents into urethra The Urethra Extends from neck of urinary bladder to exterior of body Circular band of skeletal muscle surrounds urethra as passes through muscular floor of pelvic cavity External urethral sphincter under voluntary control In males: Extends 18–20 cm to external opening, or external urethral orifice, at tip of penis In females: Very short (2.5–3.0 cm) from bladder to external urethral orifice near anterior wall of vagina Organs for the Conduction and Storage of Urine. Left ureter Rectum Peritoneum Urinary bladder Pubic symphysis Prostate gland External urethral sphincter Urethra External urethral a Male orifice Organs for the Conduction and Storage of Urine. Rectum Right ureter Peritoneum Urinary Uterus bladder Pubic symphysis Internal urethral sphincter External urethral sphincter Vagina Urethra b Female Organs for the Conduction and Storage of Urine. Ureter Ligaments Detrusor muscle Ureteral openings Center of trigone Neck Internal urethral sphincter Prostate gland External urethral Urethra sphincter c Urinary bladder in male  Produces, stores, nourishes, and transports reproductive cells, or gametes Structures include: Reproduct Gonads Reproductive organs that produce gametes ive and hormones Ducts System Receive and transport gametes Form part of the reproductive tract Accessory glands Secrete fluids into ducts External genitalia Gametes Reproductive cells Spermatozoa (or sperm) in males Produced by male gonads, the testes Testes also secrete sex hormones called androgens (principally testosterone) Combine with secretions of accessory glands to form semen Oocyte in females Produced by female gonads, the ovaries An immature gamete When fertilized by sperm becomes an ovum Checkpoint 1. Define gamete. 2. List the basic structures of the reproductive system. 3. Define gonads.  Bozeman: Reproductive System  Gametes (sperm) are produced in the testes Travel from there through the ducts Male Epididymis Ductus deferens Reproduct Ejaculatory duct Urethra ive Accessory organs (seminal glands, System prostate gland, bulbo-urethral glands) secrete products into ejaculatory ducts Overview and urethra External genitalia include: Scrotum Penis The Male Reproductive System. Ureter Pubic symphysis Urinary bladder Major Structures of the Rectum Male Reproductive System Ducts Ejaculatory duct Accessory Glands Seminal gland Ductus deferens Prostate gland Epididymis Bulbo-urethral gland Gonad Testis Anus Urethra External Genitalia Penis External urethral orifice Scrotum The Testes and Scrotum Each testis roughly 5 cm long, 3 cm wide, 2.5 cm thick Held outside the body in fleshy pouch called the scrotum Scrotum divided into two chambers, or scrotal cavities Each cavity holds one testis Layer of smooth muscle called the dartos in scrotal dermis Cremaster muscle lies below dermis Each testis wrapped in fibrous capsule, tunica albuginea  Normal sperm development requires temperatures about 1.1ºC (2ºF) lower than body temperature Testes positioned outside pelvic cavity Testes and Dartos and cremaster muscles help Temperatu maintain proper temperature When air or body temperature increases: re Control Dartos and cremaster relax; smoothing skin and moving testes away from body When temperature decreases (cold air or jumping in cold water): Dartos and cremaster contract; wrinkling skin and moving testes closer to the body Internal Structure of the Testes Collagen fibers from tunica albuginea extend into testis, forming septa Septa divide testis into about 250 lobules Seminiferous tubules Tightly coiled tubes within each lobule Location of sperm production, or spermatogenesis Also contain nurse cells (or sustentacular cells or Sertoli cells) Nourish developing sperm Sperm pass from seminiferous tubules through rete testis into efferent ductules to the epididymis  Also called Leydig cells Interstitial Fill spaces between seminiferous tubules Cells Produce male sex hormones, or androgens Most important androgen is testosterone The Scrotum, Testes, and Seminiferous Tubules. Epididymis Ductus deferens Efferent ductule Scrotum Skin Dartos muscle Rete testis Cremaster muscle Tunica albuginea Seminiferous tubules Septum Scrotal cavity Septa a A transverse section of the scrotum and testes. The Scrotum, Testes, and Seminiferous Tubules. Seminiferous tubule containing late spermatids Spermatid Dividing Spermatogonium Seminiferous spermatocytes tubule containing spermatozoa Seminiferous tubule Capillary containing early spermatids Lumen Nuclei of nurse cells Interstitial Seminiferous tubules LM × 75 cells Spermatozoa b A section through one or more seminiferous tubules. c Nurse cells surround the stem cells of the tubule and support the developing spermatocytes and spermatids. Spermatogenesis Begins at puberty and continues until late in life (after age 70) Requires series of cell divisions in seminiferous tubules Each division produces a daughter cell that is pushed toward the lumen of the tubule Involves three processes Mitosis of stem cells Meiosis Spermiogenesis  Involves stem cells called spermatogonia Located in outermost layer of cells of seminiferous tubules Forms two daughter cells with same number of chromosomes Mitosis in Both daughter cells are diploid Spermatogen (contain both chromosomes in each pair) esis Humans have 23 pairs, or 46, chromosomes One daughter cell stays in place Other is pushed toward lumen of tubule Differentiates into a primary spermatocyte Anatomy of a Spermatozoon Four distinct regions 1. ​Head Contains nucleus with chromosomes Acrosome tip has enzymes to penetrate oocyte 2. ​Neck Contains centrioles of original spermatid Connects head to middle piece 3. ​Middle piece Contains numerous mitochondria to provide ATP for movement 4. ​Tail, or flagellum Moves sperm from one place to another Spermatozoon Structure. Acrosome Head Nucleus Neck Middle piece Centrioles Mitochondrial spiral Tail (flagellum) Cell membrane of flagellum  Coiled tube attached to posterior portion of testis Functions Adjusts composition of fluid produced by seminiferous tubules The Recycles damaged spermatozoa Stores and protects maturing Epididymi spermatozoa s Takes up to two weeks for spermatozoa to travel through epididymis and complete maturation Sperm moving into ductus deferens are physically mature, but immobile Substance secreted by epididymis prevents premature capacitation, or full sperm activation The Ductus Deferens Also called the vas deferens Spermatozoa and fluid propelled along ductus deferens by peristalsis Passes through the inguinal canal into the abdominal cavity within the spermatic cord Passes laterally to urinary bladder Curves down past ureters toward prostate gland Expanded distal portion called the ampulla Sperm can be stored here for up to several months  Short passageway Formed where ampulla of ductus Ejaculator deferens joins with duct of seminal gland y Duct Goes through wall of prostate gland Empties into urethra The Male Reproductive System. Ureter Pubic symphysis Urinary bladder Major Structures of the Rectum Male Reproductive System Ducts Ejaculatory duct Accessory Glands Seminal gland Ductus deferens Prostate gland Epididymis Bulbo-urethral gland Gonad Testis Anus Urethra External Genitalia Penis External urethral orifice Scrotum The Ductus Deferens. Ureter Urinary bladder Lumen Ductus deferens of ductus deferens Ampulla of ductus deferens Seminal gland Smooth muscle Ejaculatory duct Prostate gland LM × 120 Urethra This b light micrograph shows the Bulbo-urethral gland thick layers of smooth muscle in the wall of the ductus deferens. Thisaposterior view shows the ductus deferens in relation to nearby structures.  Extends from urinary bladder to tip of penis The Male 18–20 cm long Urethra Passageway for both urinary and reproductive systems (urine and semen) The Accessory Glands Include three glands Seminal glands, prostate gland, bulbo-urethral glands Produce fluid component of semen Functions include: Activating spermatozoa Providing nutrients needed for motility Generating peristaltic contractions to propel sperm and semen Producing buffers to counteract acidic environment of urethra and vagina  Also called seminal vesicles Contribute 60 percent of semen fluid Secretion is slightly alkaline to help neutralize acids from prostate and in vagina The Secretions contain: Fructose for metabolism by sperm Seminal Prostaglandins that stimulate smooth muscle along male and female reproductive Glands tracts Fibrinogen that forms temporary semen clot in vagina Secretions help stimulate sperm capacitation Sperm begin beating flagella, becoming motile  Small, round, muscular organ Surrounds urethra as it leaves urinary bladder Prostatic fluid Slightly acidic The Makes up about 20–30 percent of Prostate semen Contains seminalplasmin Gland Protein with antibiotic properties Appears to help prevent urinary tract infections (UTIs) Peristaltic contractions of prostate wall help propel secretions into urethra The Bulbo-urethral Glands Also called Cowper’s glands Paired glands Located at base of the penis Contribute less than 5 percent of semen Secrete thick alkaline mucus Helps neutralize urinary acids in urethra Lubricates glans penis, or tip of the penis  Fluid containing sperm and secretions of accessory glands Typical ejaculation expels about 2–5 mL of semen called ejaculate containing: 1. ​Spermatozoa Normal sperm count from 20–100 million/mL Semen 2. ​Seminal fluid Fluid component of semen Contains glandular secretions, ions, nutrients 3. ​Enzymes Protease that helps to dissolve mucus in vagina Seminalplasmin that kills bacteria Enzymes that clot semen and enzymes that liquefy it The 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 1. R​ oot is the fixed portion connected to body wall 2. ​Body (or shaft) contains erectile tissue 3. ​Glans penis is expanded distal end surrounding external urethral orifice Prepuce, or foreskin, is fold of skin over glans, often removed  Prepuce, or foreskin Fold of skin over glans penis Preputial glands on inner surface of prepuce Prepuce Secrete waxy material called smegma and Can be nutrient source for bacteria Circumcision Circumcisi Surgical removal of prepuce on Generally performed shortly after birth Lowers risk of UTI, penile cancer, and HIV infection Still controversial when not done for religious reasons Erectile Tissue of the Penis Maze of vascular channels with incomplete partitions of elastic connective tissue and smooth muscle Anterior of flaccid penis covers two corpora cavernosa Corpus spongiosum surrounds urethra In resting state: Little blood flow, arterial branches constricted During erection: Parasympathetic neurons release nitric oxide (NO) Smooth muscles in arterial walls relax Vessels dilate and channels fill with blood The Penis. Pubic Urethra symphysis Body (shaft of penis) Root of penis Ischial ramus Corpus spongiosum Corpora cavernosa (erectile tissue) Glans penis External Scrotum urethral orifice An anterior a and lateral view of a penis showing the positions of the erectile tissues The Penis. Ureter Trigone of urinary bladder Seminal gland Opening of ejaculatory duct Prostate gland Ductus deferens Bulbo-urethral Urethra gland Opening of duct from bulbo-urethral gland Corpus spongiosum Corpora cavernosa Urethra Glans penis Prepuce External urethral orifice A frontal b section through the penis and associated organs The Penis. Dorsal blood vessels Corpora cavernosa Deep artery of penis Collagenous sheath Urethra Corpus spongiosum A sectional c view through the penis Male Reproductive Hormones GnRH secreted by hypothalamus triggers release of FSH and LH from anterior pituitary FSH targets nurse 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, development of secondary sex characteristics Negative feedback controls levels of testosterone Regulation of Male Reproduction  1. List the male reproductive structures. 2. On a warm day, would the cremaster muscle be contracted Checkpoin or relaxed? Why? t 3. What happens when arteries within the penis dilate? 4. What effect would low FSH levels have on sperm production? Female Reproductive System Overview Gametes (oocytes) are produced in the ovaries Travel from there through the ducts Uterine tube Uterus Vagina Accessory glands include the greater vestibular gland External genitalia includes: Labia minora, labia majora, and clitoris The Female Reproductive System. Major Structures of the Female Reproductive System Ovary Urinary bladder Uterine tube Sigmoid colon Uterus Urethra Fornix Cervix Pubic symphysis Vagina Accessory Gland Rectum Greater vestibular gland Anus External Genitalia Labium minus Labium majus Clitoris A sagittal a section showing the female reproductive organs Female Produces sex hormones Reproduct Produces gametes ive Supports and protects developing embryo System Nourishes newborn infant Functions The Ovaries Paired, small, lumpy, almond-shaped organs Each is flattened oval about 5 cm long, 2.5 cm wide, 8 mm thick Located near lateral walls of pelvic cavity Stabilized by: Broad ligament Ovarian ligament attaches ovary to uterus Suspensory ligament attaches ovary to pelvic wall Suspensory ligament contains ovarian artery and ovarian vein  Three main functions Functions 1. Produce female gametes, or oocytes 2. Secrete female sex hormones of the Estrogens Progesterone Ovaries 3. Secrete inhibin Involved in feedback control of FSH The Female Reproductive System. Structures Uterine tube Stabilizing Ovarian artery the Ovary and vein Suspensory Infundibulum ligament Fimbriae Mesovarium (mesentery) Uterus Ovary Ovarian ligament Broad ligament Broad ligament (mesentery) (mesentery) Ureter External os Cervix Vaginal rugae Abposterior view of the uterus, uterine tubes, and ovaries Vaginal wall  Process of ovum production Begins before woman’s birth, ends at menopause Takes place each month as part of ovarian cycle Oogonia Oogenesis Female reproductive stem cells Complete mitosis before birth producing: Primary oocytes Begin meiosis between third and seventh month of fetal development Oogenesis cont. Pause at prophase I until puberty Roughly 2 million at birth; only about 400,000 left at puberty Others degenerate in process called atresia At end of meiosis I, will produce a secondary oocyte and polar body  Tertiary follicle matures through a 28-day cycle Divided into two phases, separated The by ovulation Ovarian Follicular phase (or preovulatory phase) Cycle Takes about 14 days Overview Ovulation Luteal phase (or postovulatory phase) Takes about 14 days Ovarian Cycle: Follicular Phase FSH stimulates development of follicles One tertiary follicle becomes dominant by day 5 This follicle called mature graafian follicle Expanded central chamber of follicle is the antrum Within the follicle, increases in LH prompt primary oocyte to complete meiosis I Produces secondary oocyte and a polar body By day 14 of cycle: Secondary oocyte and surrounding follicular cells (called corona radiata) float within antrum  Tertiary follicle releases secondary oocyte Distended follicle wall ruptures Ovarian Secondary oocyte and follicular Cycle: contents released into pelvic cavity Follicular fluid is sticky and keeps Ovulation corona radiata attached to surface of ovary briefly Oocyte swept into uterine tube Ovarian Cycle: Luteal Phase Empty follicle collapses Develops into endocrine structure, corpus luteum Corpus luteum secretes progesterone Without fertilization of the ovum: Corpus luteum degenerates into corpus albicans Marks the end of full ovarian cycle FSH will rise to initiate another ovarian cycle  Also called Fallopian tubes, or oviducts Roughly 13 cm in length Infundibulum is expanded end The closest to ovary Fimbriae are fingerlike projections Uterine of infundibulum Tubes Movements of fimbriae and cilia on inner surface of uterine tube help propel oocyte into uterine tube Walls of tube move oocytes toward uterus Use ciliary movement and peristalsis Oocyte Passage in the Uterine Tube Normally takes 3–4 days for oocyte to reach uterus If fertilization is to occur, Oocytes must be meet sperm within first 12–24 hours Unfertilized oocytes Degenerate Do not complete meiosis Are expelled with menstrual cycle  Pear-shaped, muscular organ Held in place by various ligaments and mesenteries Bends anteriorly over urinary bladder The Two regions, the body and the Uterus cervix Functions Protects, nourishes, and removes wastes for developing embryo and fetus Contracts to help eject fetus at birth Regions of the Uterus Body Largest region Fundus is rounded portion superior to attachments of uterine tubes Isthmus is narrowed area of body at inferior end Cervix Projects short distance into vagina External os is the opening into vagina Cervical canal opens into uterine cavity at internal os  Inner endometrium Superficial functional zone of epithelial lining undergoes monthly cyclical changes The Is sloughed off as part of uterine cycle Deeper basilar zone remains intact Uterine Muscular myometrium Wall Muscle layer contracts during labor and delivery Outer perimetrium, a layer of visceral peritoneum The Uterus. Uterine Tube Fimbriae InfundibulumAmpullaIsthmus Fundus Uterine tube of uterus Ovarian artery and vein Body of uterus Ovary Ovarian ligament Uterine cavity Round ligament Perimetrium of uterus Myometrium Broad ligament Endometrium (mesentery) Uterine artery and vein Internal os of uterus Isthmus of uterus Cervical canal Cervix External os of uterus Vagina The Uterine Cycle Also called the menstrual cycle Repeated series of changes in endometrial structure First cycle, menarche, begins at puberty Continues until menopause Interrupted by illness, stress, starvation, pregnancy Averages 28 days  Period marked by degeneration of functional zone of endometrium Triggered by drop in progesterone and estrogen as corpus luteum disintegrates Uterine Endometrial arteries constrict reducing Cycle: blood flow Secretory glands and epithelial cells Menses die Menstruation Process of shedding blood and dead cells through and out the vagina Usually lasts 1–7 days Blood loss about 35–50 mL Uterine Cycle: Proliferative Phase Begins at completion of menses Stimulated by increasing estrogen levels Surviving epithelial cells multiply and spread across endometrium Small arteries regrow New set of uterine glands forms Functional zone becomes several mm thick  Begins at ovulation Uterine glands enlarge Uterine Prepares endometrium for a developing embryo Cycle: Stimulated by progesterone and Secretory estrogens from corpus luteum Phase As corpus luteum degenerates, uterine cycle ends Menses will begin again The Vagina Elastic, muscular, distensible tube extending between uterus and exterior Parallel and anterior to rectum; posterior to the urethra Opens into vestibule Fornix Shallow recess surrounding base of cervix Hymen Epithelial fold partially blocking vaginal entrance  Bulbospongiosus muscles extend The along side of vaginal entrance Vagina Cover vestibular bulbs on either side of vaginal entrance cont. Functions of the Vagina Passageway for elimination of menstrual fluid Receives penis and holds semen during intercourse Forms lower portion of birth canal  Area containing external genitalia is vulva, or pudendum Vagina opens into vestibule Urethral opening is anterior to vaginal opening Female Clitoris, erectile tissue, is anterior to urethral opening Vestibule bound by the labia minora External Covered with smooth, hairless skin Extension covers glans of clitoris with prepuce, or hood Genitalia Lesser and greater vestibular glands moisten and lubricate vaginal entrance Mons pubis and labia majora form outer area that protects vestibule 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  External The Female External Genitalia Genitalia. Mons pubis Clitoris Prepuce Glans Vestibule Urethral opening Labia Vestibular bulb minora Vaginal entrance Hymen (torn) Labia Greater vestibular majora gland Anus  Function in lactation, milk production Controlled by hormones of the The reproductive system and placenta Gland located within subcutaneous Mammary tissue of pectoral fat pad beneath Glands skin of breasts Suspensory ligaments of the breast Bands of connective tissue forming partitions within breast Flow of Milk Milk glands found in lobules Ducts carrying milk leave lobules and merge into single lactiferous duct Milk drains into lactiferous sinus Opens onto body surface through nipple About 15–20 lactiferous sinuses open onto surface of each nipple Areola is brownish skin surrounding nipple The Mammary Gland Pectoralis major muscle Pectoral fat pad Suspensory ligaments Lobules of two lobes of the mammary gland Lactiferous duct Areola Nipple Lactiferous sinus  Hormones of the anterior pituitary Govern ovarian cycles Female Regulate secretions of ovarian Reproduct hormones Provide feedback to hypothalamus ive Hormones of the ovaries Hormones Govern uterine cycles Provide feedback to hypothalamus and pituitary Hormones and the Follicular Phase Begins each month with increase in FSH from anterior pituitary FSH stimulates follicular cells Growing follicular cells secrete estrogens Most important estrogen is estradiol Stimulate bone and muscle growth Establish and maintain secondary sex characteristics Increases CNS activity including sex drive Maintain accessory reproductive glands and organs Initiate repair and growth of endometrium  Early follicular phase Estrogen and inhibin levels are low Early and Late follicular phase Estrogens and inhibin increase Late Rapid increase in estrogen leads to Follicular increase in FSH and LH Phase Peak in estrogen levels about day 14 Triggers LH surge LH surge triggers ovulation Hormones and the Luteal Phase Corpus luteum develops and secretes progesterone Prepares endometrium for implantation of embryo Unless pregnancy occurs, corpus luteum begins to degenerate By 12 days after ovulation, progesterone and estrogen levels drop Feeds back to hypothalamus Removes inhibition of GnRH GnRH stimulates FSH production New ovarian cycle begins Regulation of Female Reproduction HYPOTHALAMUS 1 Release of Gonadotropin-Releasing Hormone (GnRH) The ovarian cycle begins with the release of GnRH, which stimulates the production and secretion of FSH and the production—but not the secretion—of LH. Release of GnRH 2 Follicular Phase of ANTERIOR the Ovarian Cycle 3 LOBE OF Luteal Phase of The follicular phase begins when PITUITARY the Ovarian Cycle Production Production FSH stimulates growth and and secretion of LH development of a group of tertiary GLAND Elevated estrogen levels stimulate LH of FSH follicles. One follicle becomes secretion. dominant. Secretion of LH On or around day 14, a massive As tertiary follicles develop, FSH surge in LH level triggers (1) the levels decline due to the negative completion of meiosis I by the feedback effects of inhibin. primary oocyte, (2) the forceful rupture of the follicular wall, (3) ovulation, roughly 9 hours after Developing follicles also secrete Negative the LH peak, and (4) formation of estrogens, especially estradiol, feedback the corpus luteum. the dominant hormone prior to ovulation. After OVARY day 10 The corpus luteum secretes Before In low concentrations, estrogens Meiosis I progesterone, which stimulates and day 10 inhibit LH secretion. This inhibition completion sustains endometrial development. gradually decreases as estrogen Follicle Ovulation levels climb. development Corpus luteum After ovulation, progesterone levels formation rise and estrogen levels fall. This Secretion of inhibin suppresses GnRH secretion. If pregnancy does not occur, the Secretion of corpus luteum will degenerate after estrogens Secretion of 12 days, and as progesterone levels progesterone decline, GnRH secretion increases, and a new cycle begins. Effects Stimulates Establishes and Maintains Stimulates KEY on CNS bone and maintains female accessory endometrial Stimulation muscle growth secondary sex glands and growth and characteristics organs secretion Inhibition  Drop in progesterone and estrogen: Triggers degeneration of endometrium and menses Hormones Rise in estrogen: and the Stimulates proliferative phase Involves regeneration of functional Uterine zone of the endometrium Cycle Rise in progesterone: Stimulates secretory phase Uterine glands enlarge and increase secretions  FOLLICULAR PHASE OF OVARIAN CYCLE LUTEAL PHASE OF OVARIAN CYCLE 50 Regulation of 40 LH Female Gonadotropic hormone 30 Reproduction levels (IU/L) 20 FSH 10 Follicle development during the ovarian cycle Corpus Mature Corpus Tertiary follicle development Ovulation luteum corpus albicans formation luteum Progesterone Ovarian hormone levels Estrogens Inhibin Destruction of Repair and regeneration Secretion by functional zone of functional zone uterine glands Endometrial changes during the uterine cycle Phases of the PROLIFERATIVE MENSES SECRETORY PHASE uterine cycle PHASE 36.7 Basal body temperature (ºC) 36.4 28/0 7 14 21 28/0 Days  1. Name the structures of the female reproductive system. 2. As the result of infections such as gonorrhea, scar tissue can block both uterine tubes. How would this Checkpoin blockage affect a woman’s ability to conceive? t 3. What benefit does the acidic pH of the vagina provide? 4. Which layer of the uterus is sloughed off, or shed, during menstruation?  5. Would the blockage of a single lactiferous sinus interfere with delivery of milk to the nipple? Explain. 6. What changes would you expect to Checkpoin observe in the ovarian cycle if the LH surge did not take place? t cont. 7. What effect would blockage of progesterone receptors in the uterus have on the endometrium? 8. What event in the uterine cycle occurs when estrogen and progesterone levels decline? Menopause Time when ovulation and menstruation cease Typically occurs between ages 45–55 Perimenopause is time period before menstrual cycle becomes irregular Accompanied by a decline in estrogen and progesterone Due to 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 Urethral and vaginal walls thin Linked to osteoporosis Neural effects include “hot flashes,” anxiety, depression  Crash Course: Reproductive System part 1 https://www.youtube. com/watch?v=RFDatC chpus  Crash Course: Reproductive System part 2 https://www.youtube. com/watch?v=-XQcnO 4iX_U