Male and Female Reproductive System - Notes | KN 252, Study notes of Kinesiology

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Male Reproductive System [W13 – Lecture 1]  Functions of male reproductive system o Spermatozoa – male germ cell (or gamete) o Androgens – male sex hormones (primarily testosterone) o Facilitates fertilization for transfer of spermatozoa to female genital tract during copulation  Testes – 2 paired organs that have two functions o Gametogenesis – production of gametes (is done by both male and female)  Spermatogenesis – male producing a gamete called spermatozoa  Once spermatozoa completes division, it will change shape to look like a motile sperm o Steroidogenesis – production of testosterone (steroid hormones) o Embryologically, the testes develop in abdominal cavity and descend to scrotum during seventh month of intrauterine life [deep inguinal ring  inguinal canal  superficial inguinal ring]  Inguinal canal – the testes passes through here by eight month of fetal life o Tunica vaginalis – double layer of peritoneum that covers the testes  As the testes descend, they become covered with the tunica vaginalis o Tunica albuginea – thick fibrous connective tissue layer that is deep to the tunica vaginalis  Forms a connective tissue septum that projects into testes and divides it into pyramidal lobes o Seminiferous tubules – where spermatogenesis occurs; within each of the lobules  Each tubule is 80 cm long and has two open ends at area called tubulus rectus  Spermatogenic cells – involved in various stages of cell division; located in seminiferous  Sperm producing cells – go through a series of development and form in outer most portion of tubule towards the lumen  Sertoli cells – protects and nourishes the spermatogenic cells and produces the hormone inhibin  Inhibin – controls rate of sperm production  Interstitial cells of Leydig – produce testosterone; they are interspersed between the seminiferous tubules o Tubulus rectus – the seminiferous tubule begins here and ends here  Scrotum – outside the body’s cavity, the testes are sitting in this sac by birth o Maintains temperature 2-3 degrees below body’s temperature which is essential for spermatogenesis o Gubernaculum – fastens the testes to the inferior border of scrotum The Male Duct System: seminiferous tubules, tubulus rectus, rete testis, efferent ductules, epididymis  Seminiferous tubules  tubulus rectus  rete testis  efferent ductules  epididymis  Tubulus rectus – straight part of seminiferous tubules  Rete testis – collects sperm from all seminiferous tubules; complex series of tubules on posterior side of testes  Efferent ductules – series of ducts where the rete testis empties into  Epididymis – where spermatozoa is stored; efferent ductules empty into here o Capacitation – maturation process of sperm while stored in epididymis o Sperm is transferred from head of epididymis  to tail  then to vas deferens  Vas deferens – continues through the spermatic cord and ends in ejaculatory duct; on both sides o Spermatic cord – contains the vas deferens and testicular artery/vein (gonadal)  The vas deferens passes through superficial inguinal ring  inguinal canal  deep inguinal ring  enters pelvis  attaches to ejaculatory duct o Vas deferens ampulla – enlarged portion of vas deferens and is connected to seminal vesicles o Vasectomy – cutting vas deferens which inhibits release of spermatozoa  Ejaculatory duct – formed by the joining of vas deferens ampulla and the duct of seminal vesicle gland o The ejaculatory duct is located within the prostate gland o Prostatic urethra – part of urethra where the ejaculatory duct empties into o There is an ejaculatory duct, vas deferens, and seminal vesicle on the right side and left side *Sertoli cells are also called sustentacular cells, they are large and triangular in shape *Testes are initially retroperitoneal *Inguinal hernia is when the rings stay open (more common in male)  Urethra o Trigone of bladder – triangular area of bladder o Prostatic urethra – part of urethra passing through prostate gland o Membranous urethra – part of urethra passing through pelvic/urogenital diaphragm  Pelvic/Urogenital diaphragm – forms the floor of pelvis o Spongy/Penile urethra – urethra passing through corpus spongiosum  Semen – formed by secretions of three accessory glands (90%) o Seminal vesicles – highly coiled glands; lies on posterior aspect of bladder  Located lateral to vas deferens and connects to its ampulla  Secretions empty into ejaculatory duct which empties into prostatic urethra o Prostate gland – dense fibroelastic connective tissue and smooth muscle; located on base of bladder  It encircles urethra as it exits bladder and its secretions empty into prostatic urethra o Bulbourethral glands – has a small duct which empties into spongy urethra within layer of urogenital diaphragm  Spermatic cord – connective tissue sheet that encloses the vas deferens, testicular arteries, “pampiniform plexus of veins”, and nerve fibers; it suspends the testes from the body within the scrotum o Pampiniform plexus of veins – venous plexus; cools the blood before it comes to testes o Cremaster muscle – thin layer of skeletal muscle fibers that cover spermatic cord  Fibers are composed of muscle fibers from internal abdominal oblique muscle  Protects spermatic cord as it passes through the inguinal canal during development o Testicular vessels comes down from abdominal aorta to bring blood supply to testes o Vas deferens leads the sperm to come up through spermatic cord  to enter pelvis go behind the bladder  into ejaculatory duct  The scrotum ~ outer part is covered by skin o Dartos muscle – layer of smooth muscle within superficial fascia and located within skin of scrotum  Responsive to temperature changes, contracts when temperature is cooler and relaxes when it’s warmer  Controlled by autonomic nervous system (since it’s smooth muscle) o The cremaster muscle and dartos muscle are responsible for moving the testes away/closer to body Penis ~ formed by corpus spongiosum and two corpora cavernosa  Corpus spongiosum – composed of erectile tissue and has spongy urethra running through it o Erectile tissue – can accumulate blood which makes it rigid o Urethra is the opening in the center o Glans penis – the enlarged corpus spongiosum  Prepuce – layer of skin surrounding the glans of penis  What’s removed during circumcision o Spongy urethra begins at base of penis and continues distally through corpus spongiosum  Bulbospongiosus muscle – covers the spongy urethra; compresses urethra to empty off semen or urine and helps maintain erection by compressing veins  Innervated by pudenal nerve  Corpora cavernosa – composed of only erectile tissue; there are two of them o Corona – where each corpora corpus cavernosa begins  Continue medially to form two corpora cavernosa which form most of shaft o Ischiocavernosus muscle – skeletal muscle that covers the corpora cavernosa  Pudenal nerve – innervates this muscle; comes from sacral plexus  Helps maintain erection by compressing veins to retain blood in erectile tissue Female Reproductive System [W13 – Lecture 2]  Functions of female reproductive system o Ova – female germ cell, it’s the mature gamete o Produce female hormones: estrogen and progesterone o Facilitate fertilization, gestation period (length of pregnancy), and to nurture infants by lactation  Ovaries – paired structures on either side of uterus near lateral walls of pelvis; they are held in place by ligaments; and has a cortex and medulla o Gametogenesis – production of gametes  Oogenesis – production of oocytes in female o Steroidogenesis – production of estrogen and progesterone (steroid hormones) o Ovarian ligament – anchors ovary medially to the uterus o Suspensory ligament – fold of peritoneum that covers the ovarian vessels as they descend from higher levels to the ovaries  Ovarian vessels – originate just below renal vessels off abdominal aorta o Broad ligament – fold of peritoneum which covers the uterus like a tent; this wide band of tissue stabilizes the uterus to lateral pelvic walls  Mesovarian – part that covers the ovaries  Mesosalpinx – part that covers the oviduct o Germinal epithelium – layer of simple cuboidal epithelium that covers the ovaries  The original germ cells migrate to ovaries o Tunica albuginea – dense layer of connective tissue; deep to germinal epithelium (similar to testes) o Cortex of Ovary – contains oocytes surrounded by tissue called “ovarian follicles”  The follicles vary in size depending on state of development  Follicle cells – cells that surround the oocyte  Primordial follicle – oocyte surrounded by flattened layer of follicular cells  The cells are waiting for development;  Primary follicles – developing primordial follicle; oocyte surrounded by cuboidal follicular cells  Secondary follicle – developing primary follicle; surrounded by 1-4 layers of follicular cells and contains an antrum; also has granulosa cells  Antrum – space formed within the follicular cell  As the secondary follicle grows, it will grow larger and form blister on surface of ovaries which will ultimately release the ovum  Vesicular follicle – mature follicle that is ready to rupture; has several layers of follicular cells and a large antrum  Ovulation – follicle ruptures to release its oocyte  Corpus luteum – remaining follicular cells that stay in ovary once oocyte has been ovulated  Acts as a temporary endocrine gland secreting estrogen and progesterone for some time Female Duct System – fimbria  infundibulum ampulla  isthmus  uterine [pathway of ovum]  Uterine tubes/Oviducts/Fallopian tubes – transmits ovum from ovary to uterus and provides necessary environment for fertilization and for initial development of conceptus o Conceptus – fertilized ovum  Isthmus – first part of oviduct closest to uterus and embedded in the uterus  Ampulla – enlarged area of oviduct and is site of fertilization; comprises 2/3 of oviduct o Where spermatozoa comes into contact with ovum and begin formation of conceptus  Infundibulum – widening or funnel shaped segment at distal end of ovary  Fimbria – finger like projections which carefully caress but doesn’t attached to ovary o Ciliated cells – numerous cells found on fimbria which helps to move ovum into infundibulum and then ampulla *The granulosa cells that remain on the oocyte after ovulation is called “corona radiata” *Corpus albicans is a scar left over by the corpus luteum when no fertilization occurs Uterus – located in pelvis between urinary bladder anteriorly and rectum posteriorly; it’s a hallow organ with thick walls of smooth muscle  Its function is to receive, retain, and nourish the fertilized ovum  Body – center of uterus  Fundus – upper rounded part that projects slightly above level where oviducts enter  Isthmus – narrowing down of uterus  Cervix – lower most narrow part of uterus; contains the cervical canal o Cervical canal – within cervix that communicates with internal part of uterine cavity and externally with vaginal cavity  Cardinal ligament – stabilizes cervix; on either side of uterus at level of cervix [embedded in broad ligament]  Uterus sacral ligament – secures uterus posteriorly to sacrum  Round ligament of uterus – attaches uterus to anterior pelvic wall o Continues anteriorly, passes through the inguinal ligament & anchors itself to labia majora  Like the spermatic cord  Layers of uterine wall o Perimetrium – outer most layer of cervix is covered by thin layer of visceral peritoneum o Myometrium – thick layer of smooth muscle o Endometrium – inner layer which undergoes changes during the menstrual cycle in response to hormonal control; is divided into two parts:  Stratum basalis – most deeply placed portion of endometrium  Stratum functionalis – part of endometrium that thickens in response to hormones in anticipation of fertilized ovum implanted in endometrial wall  If no fertilized ovum is planted, the hormone levels change and stratum functionalis is flushed off Vagina and External Genitalia  Vagina – the birth canal; fibro muscular tube connecting cervix to exterior part of body o Pathway for delivery of baby at birth and path of menstrual flow o Female cockatiel organ – necessary to receive sperm to fertilize ovum o Hymen – layer of connective tissue that partially covers the opening o Urethra – located anterior to vagina and posteriorly to rectum  Vaginal fornix – two upper extensions of vagina on either side of cervix  Vulva – external genitalia that covers opening of vagina  Mons pubis – fatty round area that covers the pubic symphysis  Labia majora – layer of skin and connective tissue continuous with mons pubis and ends at perineal body  Perineal body – central area of connective tissue between anterior and posterior portion of perineal region o The perineal body is just anterior to opening on anal canal; perineal body is posterior to everything else  Labia minora – thin layer of skin which surrounds vaginal opening in an area called vestibule o Vestibule – within this area is opening of urethra and vagina  Clitoris – formed by erectile tissue; located anteriorly to meeting of labia minor  Prepuce of clitoris – fold of skin from labia minora which comes over the clitoris  Perineum – triangle shaped area that is divided into a urogenital triangle and anal triangle o Area between the pubic arch and coccyx and between two ischial tuberosity o Anal triangle is same between female and male; urogenital triangle is different  Ischiocavernosus muscle – covers corona of clitoris; innervated by pudenal nerve o Helps maintain erection in clitoris  Bulbospongiosus muscle – around vaginal opening; innervated by pudenal nerve o Compresses veins to help contain blood within erectile tissue  Greater vestibular gland – accessory gland similar to bulbourethral gland to male  Autonomic nervous system innervated pelvis organs by pelvic splanchnic nerves o Parasympathetic ~ S2, S3, S4; same as males o Sympathetic ~ L1 and L2; same as males  There are changes in the reproductive tract of pregnant and non-pregnant women o Uterus lies posterior and slightly superior to bladder because it’s flexed forward o During pregnancy, baby is large and causes uterus to become heavy and still remains flexed over bladder  Ovarian arteries and internal iliac artery supply blood to the female productive system o Internal iliac artery supplies the bladder, uterus, and contributes to blood supply to oviduct and ovaries o Ovarian arteries are the primary blood supply to the ovaries  The ovaries descend to pelvis from abdominal cavity (but don’t leave pelvis) Mammary glands – develop in response to estrogen and progesterone produced by ovaries  Areola – pigment area around nipple  Nipple – composed of lactiferous duct  Lactiferous duct – deliver milk during lactation  Suspensory ligaments – connective tissue septa that divides the lobes  Alveoli – composed of glandular tissue that responds to hormonal stimulation to produce milk  Prolactin – stimulates milk production  Oxytocin – stimulates milk letdown and uterine contractions Electrolyte Balance ~ equally important as fluid balance  Sodium – most important ion in regulating water balance; higher extracellulary o Sodium contributes to water movement, so it must be regulated and balanced o Sodium concentration is higher in interstitial fluid and plasma (extracellular fluids) o Sodium contributes to osmotic pressure in different chambers o Sodium has limited permeability; the ”sodium door” is shut most of the time  Sodium permeability is increased only when there is an action potential  This is a good thing, because wherever sodium goes, water follows  Regulation of Na+ and water balance o Aldosterone – hormone secreted in response to angiotensin (converted by renin)  Aldosterone travels to kidney tubules and causes an increase in reabsorption of Na+  It also causes kidney tubules to secrete K+ into urine  Water will follow Na+ into blood stream o With increase in Na+/water retention, you get increase in blood volume  So this mechanism kicks in when there is low blood volume o With increase in blood volume, there is an increase in blood pressure  Blood pressure is important for maintaining normal ΔP o As the concentration of Na+ and water changes, there is a change in osmolality  Change in osmolality determines thirst mechanisms  High Na+ concentration triggers thirst mechanism & release of ADH so Na+ and water balance is restored  ADH – causes collecting duct to become permeable to water (but not to Na+) o Baroreceptors ~ has some input into how much blood volume there is (not concentration ratio)  As blood volume/pressure increases, baroreceptors trigger a “reflex response” which results in “pressure dieresis” from kidney  If blood pressure is too high, there is an increase in glomerular filtration rate  This removes extra water or Gatorade o Antidiuretic hormone (ADH) – released from posterior pituitary when thirsty (hypothalamus)  ADH is synthesized in hypothalamus  Osmoreceptors – respond to changes in osmolality of blood and stimulates hypothalamus  Osmoreceptors are in neighboring region of hypothalamus  Remember, kidney responds to ADH by making collecting duct more permeable water o Atrial natriuretic factor (ANH) – released from atria in response to increased pressure and volume  Lowers blood pressure by inhibiting release of ADH, renin, and aldosterone  ADH, renin, and aldosterone are released when blood volume is low (review) o Other hormones that effect electrolyte fluid  Estrogen – increases Na+ reabsorption at kidney (female steroid)  Progesterone – decreases Na+ retention at kidney (female steroid)  During pregnancy and menstrual cycle there is lot of fluid retention  Glucocorticoids – increases Na+ absorption  High levels of glucocorticoids can increase edema   Potassium balance o K+ is balanced mainly at kidney between reabsorption and secretion  Aldosterone ~ regulates secretion of K+ at distal convoluted tubule and collecting duct  Calcium balance o Parathyroid hormone – released when Ca2+ levels are low  Osteoclasts release Ca2+ into blood stream, intestines absorb calcium, & kidneys reabsorb Ca2+ o Calcitonin – released when Ca2+ levels are high (opposite effects)  Causes bones to reuptake to Ca2+  Magnesium balance ~ most is absorbed in loop of henle; o magnesium is important cofactor in carbohydrate and protein metabolism (regulation is unclear)  Anions ~ regulation depends on acid-base balance of blood (normally, most of it is reabsorbed) [H + ] ~ Normal pH= 7.35 – 7.45 [W13 – Lecture 4]  It is important to maintain a normal pH because protons alter the configuration of structural and enzymatic proteins making them useless o In human body, neutral pH is between 7.35 – 7.45 o Some molecules can cause acidosis or alkalosis due to “buffer systems”  Acidosis – occurs when pH in body is less than 7.35; generated through normal cellular metabolism o Phosphoric acid ~ generated by breakdown of phosphorus containing proteins and lipid o Lactic acid ~ generated from glycolysis o Ketoacids ~ generated from fat breakdown o HCl ~ generated normally in stomach (stomach wall is protected by mucous) o Carbonic acid ~ travels in blood and generated by kidney  Alkalosis – occurs when pH is greater than 7.45 o HCO3 ~ generated by kidney and respiratory system o HPO4 - (monohydrogen phosphate) ~ found in kidney o NH3 (ammonia) ~ found in kidney and formed by glutamine metabolism  Buffer systems – regulates pH o Buffers – weak acids or weak bases that don’t dissociate in water  The buffers can go back in forth between acidic form or basic form (one way or the other)  The body uses buffers to keep extra H+ under control and to maintain homeostasis Buffer system – there are 3 major chemistry systems the body uses to buffer against excess acid or too little acid  Bicarbonate system – prevents tissue damage by binding bicarbonate with H+ o H+ + HCO3 - ↔ H2CO3 ↔ H2O + CO2  Carbonic acid (H2CO3) is harmless, but the dissociation of it releases H + which is harmful o Carbonic acid (H2CO3) – weak acid so it’s a good buffer o Alkaline reserve – amount of available bicarbonate ions (HCO3 - ) that absorb additional H +  Supply of bicarbonate is limitless because of the respiratory system removing CO2  Phosphate system – works well until pH drops below 5.5 o Na2HPO4 + H + ↔ NaH2PO4 + Na +  Monohydrogen and dihydrogen found within cells and urine  Monohydrogen and dihydrogen formed by intracellular metabolism  There are more found intracellulary than extracellulary [except urine]  Protein system – powerful because there are number of proteins that can accept or donate H+ o Amphoteric – function as either acid or base (proteins can function as amphoteric) o Carboxyl group – acid side of amino acid because it can donate an H+  R-COOH  RCOO- + H+  Carboxyl group releases H+ when pH rises o Amine group – base side of amino acid because it accepts an H+  R-NH2 + H +  RNH3 +  Picks up H+ when pH falls o Hemoglobin – protein that keeps the acidity within the red blood cell normal when CO2 is exchanged  H+ + Hb  HHb  Hemoglobin (without O2) can pick up H + Respiratory regulation of [H + ] ~ H + regulated by using the 3 chemical buffer systems  CO2 exchange occurs: between tissue and red blood cell and in the lungs o Cellular level ~ CO2 converted to bicarbonate slowly in plasma; or it can dissolve in plasma  CO2 given off in tissue  enters plasma  forms carbonic acid  forms bicarbonate o Erythrocyte ~ CO2 converted to bicarbonate quickly in red blood cell  H2O + CO2 H2CO3  H + + HCO3 -  Forms bicarbonate much more quickly in red blood cell due to carbonic anhydrase  The hydrogen given off is quickly taken up quickly by a hemoglobin (protein system) o Lung ~ CO2 is expelled from lungs and is a reversal of the reaction  H+ + HCO3 -  H2CO3  H2O + CO2 (reverse reaction) [measured for respiratory function]  The H2O molecule is ridding the H + (extra proton)  Chemoreceptors ~ increases respiratory rate when it senses a drop in pH  Increase of H+ in CSF and medulla also increases respiratory rate  Respiratory system ~ very effective at buffering pH o If you double alveolar ventilation and exhale more CO2, you increase pH by 0.2 units  Change from 7.35  to 7.55  This is why you feel dizzy when you breath slowly and deeply (blow a balloon) o Example ~ marathon runners, swimmers easily remove CO2 and control acidosis (beneficial) Renal Regulation of [H + ] ~ kidney helps with hydrogen concentration through three “slow-acting systems”  Kidney removes metabolic acids o Lactic acid ~ comes from glucose metabolism o Phosphoric acid ~ comes from proteins and lipid breakdown o Uric acid ~ comes from nucleic acids o Ketones ~ comes from lipid metabolism  Bicarbonate system – puts HCO3 - into blood and releases H + in urine as H2O o Bicarbonate system takes CO2 in blood and combines it with H2O. There is carbonic anhydrase present in proximal convoluted tubule which helps form carbonic acid  H2O + CO2 H2CO3  H + + HCO3 - [reaction occurs in proximal convoluted tubule]  HCO3 - is returned to peritubular capillary which contributes to alkaline reserve  The H+ is put into filtrate in exchange for Na+  H+ + HCO3 -  H2CO3  H2O + CO2 [reaction occurs in filtrate/urine]  CO2 can transfer back to proximal convoluted tubule if needed, but not H +  The H2O molecule leaves the body as urine (getting rid of extra acid)  Phosphate system – puts HCO3 - in blood and releases H + in urine as H2PO4 - o Phosphate system takes the hydrogen ion from the proximal convoluted tubule and combines it with HPO4 2- which exists in urine  H2O + CO2 H2CO3  H + + HCO3 - [reaction occurs in proximal convoluted tubule]  HCO3 - is returned to peritubular capillary which contributes to alkaline reserve  The H+ is put into filtrate using an ATPase  HPO4 2- + H +  H2PO4 - [reaction occurs in filtrate/urine]  H2PO4 - leaves the body as urine  Protein system – puts HCO3 - in blood and releases H + in urine as NH4 + o Protein system uses glutamine and removes it of its amine group ultimately breaking it down into bicarbonate and ammonium ion (through deamination, oxidation, and acidification)  Glutamine  2NH4 + + 2HCO3 - [reaction occurs in proximal convoluted tubule]  HCO3 - is returned to peritubular capillary which contributes to alkaline reserve  NH4 is put into filtrate in exchange for sodium ion o NH4 leaves body in urine (no further reactions) *Respiratory acidosis is when there is increase of CO2 in blood