Reproductive System HLSC 2P95 Lecture Notes PDF

REPRODUCTIVE SYSTEMS Introduction Male Female  The Reproductive System designed to perpetuate the species – The males produce gametes called sperm cells – The female produce gametes called ova – The joining of a sperm cell and an ovum is fertilization – Fertilization results i...

REPRODUCTIVE SYSTEMS Introduction Male Female  The Reproductive System designed to perpetuate the species – The males produce gametes called sperm cells – The female produce gametes called ova – The joining of a sperm cell and an ovum is fertilization – Fertilization results in the formation of a zygote  Organization of the Reproductive System The reproductive system includes: 1. Gonads (organs): Testes / Ovaries 2. Reproductive tract 3. Accessory glands 4. Perineal structures: External genitalia Anatomy of the Male Reproductive System Ducts: Accessory Glands Ejaculatory duct Seminal gland Membranous urethra Prostate gland Spongy urethra Bulbo-urethral gland Ductus deferens Epididymis Gonad: testis External Genitalia: Penis scrotum  Male Reproductive System Prostatic urethra Pubic symphysis Urinary Major Components of the bladder Male Reproductive System Rectum Accessory Ducts Ejaculatory duct Glands Membranous urethra Seminal gland Spongy urethra Ductus deferens Prostate gland Epididymis Corpus cavernosum Bulbo-urethral gland Corpus spongiosum External urethral orifice Anus Penis External Genitalia Scrotum Gonad Testis Fig 27.1  The Testes Testes hang inside a pouch called the scrotum, which is on the outside of the body Testicle size 5 cm long 3 cm wide 2.5 cm thick 10–15 g  Descent of the Testes During development, the testes form inside the abdominal cavity near the kidneys Testes descend towards the scrotum by passing through the inguinal canals The ductus deferens, blood vessels, lymphatics, and nerves remain bundled to the testes in the spermatic cords  Diaphragmatic Developing ligament kidneys Mesonephric Gonads duct Gubernaculum testis 2 months Kidney Diaphragmatic ligament Epididymis Testis 3 months Epididymis Testis Urinary bladder 4 months b Anterior views of the opened abdomen at representative stages in the descent of the testes. Fig 27.2 © 2015 Pearson Education, Inc.  Testicular artery Ureter and vein Superficial Vas deferens inguinal ring Epididymis Scrotal cavity (opened) lined Testis by tunica vaginalis Gubernaculum testis 7 months Sperm develops at Ureter Testicular artery 96.6 and vein Fahrenheit Urinary bladder Spermatic cord Scrotum (opened) Birth b Anterior views of the opened abdomen at representative stages in the descent of the testes. Fig 27.2  The Spermatic Cords Testicular artery Inguinal Testicular vein canal Inguinal Spermatic Cord ligament Superficial Genitofemoral nerve inguinal ring Deferential artery Ductus deferens Spermatic cord Pampiniform plexus Testicular artery ilioinguinal nerve Fig 27.3 The scrotum & position of the testes Divided into two chambers (scrotal cavities) Separated by the perineal raphe extends from the anus, across the scrotum, and along the anterior surface of the penis Tunica Vaginalis membrane covers the outside of each testis and lines the scrotal cavity  The scrotum & position of the testes Cremaster muscle within Scrotal cavity cremasteric fascia Testis (covered by visceral Layers of the Scrotum layer of tunica vaginalis) Superficial scrotal fascia Parietal layer of tunica vaginalis (inner lining of cremaster, Dartos muscle facing scrotal cavity) Scrotal skin (cut) Perineal raphe  Muscles of the scrotum 1. Dartos muscle. Contraction cause the wrinkling of the scrotal surface 2. Cremaster muscle Contraction tenses the scrotal sac and pulls it closer to the body The temperature for sperm development is 2°F cooler than body temperature  The Testes Ductus deferens Mediastinum of testis Epididymis Efferent ductule Rete Scrotum testis Skin Dartos muscle Straight Superficial tubule scrotal fascia Cremaster muscle Seminiferous tubules Tunica vaginalis Tunica albuginea Septa Scrotal cavity Septa Lobule Perineal raphe Fig 27.4  Histology of the Seminiferous tubule containing late spermatids Seminiferous Seminiferous tubule containing spermatozoa Tubules containing early spermatids Seminiferous tubule There is a space between the coils of the seminiferous tubules Seminiferous tubules LM × 75 The cells within this space are the a Seminifer ous tubules in sectional view interstitial cells Interstitial cells Dividing Interstitial cells produce and spermatocytes Nurse cell release testosterone Spermatogonia Spermatids Lumen Heads of maturing spermatozoa Tubular capsule Seminiferous tubule LM × 350 Fig 27.5 c Spermatogenesis within one segment of a seminiferous tubule  Interstitial cells Dividing spermatocytes Nurse cell HINT: Spermatogonia MIGHT BE ON LAB Spermatids EXAM THIS HISTOLOGY Lumen SLIDE Heads of maturing spermatozoa Tubular capsule Seminiferous tubule LM × 350 c Spermatogenesis within one seg© m2e0n1t5 o Pefaa rsosneEm duin caitfie onr,oIu ncs. tubule Fig 27.5 Spermatogenesis and Meiosis Spermatogenesis Formation of sperm cells Meiosis – 1 to 2 to 4 Set of events involved in producing the sperm cells begins in the outer layer of the seminiferous tubules Spermatogonia Stem cels that will become sperm cells  Spermatids beginning Spermatids completing LUMEN spermiogenesis spermiogenesis Initial spermiogenesis Secondary spermatocyte Primary spermatocyte Secondary spermatocyte preparing in meiosis II for meiosis I Level of blood testis Nurse Barrier (nurse cells) cells Fibrocyte Tubular capsule Capillary Interstitial cells Spermatogonium Basal compartment d The blood–testis barrier and the structure of the wall of a seminiferous tubule Fig. 27.5  Nurse Cells Function of Nurse Cells Maintenance of the blood-tests barrier Support of spermatogenesis – testosterone and FSH Support of spermiogenesis – provides nutrients Secretion of inhibin – Controls the rate of sperm formation Secretion of androgen-binding protein – Binds testosterone within the seminiferous tubules so testosterone will continue to have an effect on spermiogenesis  SPERMATOGENESIS MITOSIS of spermatogonium (diploid) Primary spermatocyte (diploid) BLOOD-TESTIS BARRIER DNA replication Synapsis and Primary spermatocyte tetrad formation Tetrad MEIOSIS I Secondary spermatocytes MEIOSIS II Spermatids (haploid) 9 weeks SPERMIOGENESIS (physical maturation) Spermatozoa (haploid) b Meiosis in the testes showing the fates of three representative chromosomes Fig 27.5  Spermatid to Spermatozoon Spermatid (week 1) Mitochondria Fibrous sheath Tail (55 µm) of flagellum Nucleus Golgi Shed apparatus cytoplasm Dense Acrosomal fibers vesicle Middle piece Mitochondrial (5 µm) spiral Acrosomal Neck (1 µm) cap Centrioles Nucleus Nucleus b Differentiation of a spermatid into a spermatozoon Acrosomal Head (5 µm) cap Acrosomal cap Spermatozoon Microtubules (week 5) *acrosomal – contains enzymes for fertilization Fig 27.6  The male reproductive tract 1. Epididymis Head: Receives spermatozoa via the efferent ducts Body: Coiled tubes pass through the body Tail: Tubes begin to uncoil to become a single tube called the ductus deferens 2. Ductus deferens 3. Urethra 3 functions: 1. monitors and adjust fluid produced by seminiferous tubules 2. Recycling centre for damaged sperm 3. sperm maturation  Spermatic cord The Epididymis Ductus deferens Head Efferent ductules Straight tubule Rete testis in mediastinum Body Seminiferous tubule Tunica albuginea covering testis Scrotal cavity Tail *7 m long!! If you stretch out Epididmysis a Diagrammatic view of the testis and epididymis Fig 27.7  The ductus deferens (vas deferens) Begins at the tail of the epididymis Enters the abdominal cavity through the inguinal canal Around the urinary bladder & ureter Descend through the prostate gland Before entering the prostate gland, the ductus deferens expands (ampulla) & becomes the ejaculatory duct  a A posterior view of the urinary bladder and prostate gland showing subdivisions of the ductus deferens in relation to surrounding structures. Ureter Urinary bladder Ductus deferens Seminal gland Ampulla of ductus deferens Duct of seminal gland Ejaculatory duct Prostate gland Prostatic urethra Bulbo-urethral glands Urogenital diaphragm Fig 27.8  The urethra Prostatic urethra Urinary bladder Rectum Membranous urethra Spongy urethra External urethral orifice Fig. 27.1  The accessory glands Seminal glands (~60% of semen volume) Seminal fluid (high concentration of fructose, prostaglandins, clotting factors) Contents empty into the ductus deferens Prostate gland (~20-30% of semen volume) Weakly acidic, contents empty into the prostatic urethra Secretions consist of seminalplasmin (antibiotic thought to prevent UTIs in males) Bulbo-urethral glands (~5% of semen volume) Contents empty into the spongy urethra Secretions (thick, sticky, alkaline mucus, neutralizes urinary acids, provides lubrication for the tip of the penis)  Ejaculate Semen (sperm + seminal fluid + prostate fluid) Each ejaculate = 1 teaspoon of semen 200-500 million sperms Taste can be affected  The accessory glands Ureter Urinary bladder Ductus deferens Seminal gland Ampulla of ductus deferens Duct of seminal gland Total ejaculate ~2-5ml Ejaculatory duct 2-100 million sperm Prostate gland Prostatic urethra Bulbo-urethral glands Urogenital diaphragm Fig 27.8  Penis Multifunctional, Sexual pleasure, urination; reproduction Composed of spongy tissues; no bones about it Top two -> corpora cavernosa Bottom one -> corpus spongiosum – Also contains the urethra Tumescence -> filling with blood - Vascular phenomenon Hangs to the left! Dr. Tony Bogaert 6544 non-delinquent men who were interviewed men reported some degree of lateral asymmetry in their flaccid penis and in their testicles; less asymmetry was reported for their erect penis asymmetry typically occurred in the left direction  The penis Pubic symphysis Membranous urethra Bulb of penis Right crus of penis 2. Body (shaft) 1. Root of penis Ischial ramus Erectile Tissue Corpus spongiosum Corpora cavernosa 3. Glans Scrotum External urethral orifice Fig 27.9 The penis Ureter Trigone of urinary bladder Seminal gland Ductus deferens Prostate gland Opening of Prostatic urethra ejaculatory duct Membranous urethra Urogenital diaphragm Bulbo-urethral gland Bulb of penis Crus (leg) of penis Opening from bulbo-urethral gland Erectile Tissue Corpus spongiosum Corpora cavernosa Spongy urethra Glans Prepuce External urethral orifice Fig 27.9  The penis Dorsal artery (red), vein (blue), and nerve (yellow) Corpora cavernosa Deep artery of penis Collagenous sheath Spongy urethra Corpus spongiosum b Cross sections of the penis showing the histological relation of the urethra and three masses of erectile tissue Fig 27.9 REPRODUCTIVE SYSTEM -FEMALE- Anatomy of the Female Reproductive System Major Components: Accessory Glands Paraurethral gland Gonad: ovary Greater vestibular gland Uterine tube Uterus Vagina External Genitalia: Labia minus Mons pubis Labia majus Vaginal opening (introitus) Clitoris  Ovarian Major Components follicle of the Female Reproductive System Rectouterine Gonad - ovary pouch Uterine tube Uterus Vesicouterine Perimetrium pouch Myometrium Endometrium Cervix Pubic symphysis Vagina Accessory Glands Paraurethral glands Greater vestibular gland External Genitalia Labium minus Labium majus Clitoris Fig 27.1  Structures Stabilizing the Ovary Fimbriae Uterine tube Ovarian Mesovarium Suspensory ligament ligament Retractor Ovarian artery and vein Uterus Infundibulum Ovary Broad ligament Ureter Uterosacral ligament External os Cervix Vaginal rugae Vaginal wall a Posterior view of the ovaries, uterine tubes, and uterus along with their supporting ligaments. Fig 27.11  The ovaries Uterine tube Ovarian Medulla Corpus Cortex hilum luteum Tunica albuginea Mesenteries Stabilizing the Female Reproductive System Mesosalpinx Mesovarium Broad ligament Egg Germinal Mature nest epithelium follicle b The ovary and associated mesenteries in sectional view. Fig 27.11  The Ovarian Cycle & Oogenesis At puberty, the follicle-stimulating hormone from the pituitary gland initiates the cycle Primordial follicles develop into primary follicles several layers of cells form around the follicles Zona pellucida – coat around oocyte This layer consists of Granulose cells Provide nutrients and produce estrogen Thecal cells Surrounds the zone pellucida and release estrogen  The Ovarian Cycle & Oogenesis 2. Primary Follicles -> secondary follicles 3. Secondary follicles enlarge (follicular fluid) - secondary follicles -> tertiary follicles (10-14 days)  The Ovarian Cycle & Oogenesis 4. Ovulation: gamete release (day 14-28) Increases in luteinizing hormone (weakens the follicular wall Coincides with peak estrogen levels Egg is released into the uterine tube Primordial Primary Secondary Tertiary follicles follicle follicle follicle 4 Ovulation Follicular fluid Secondary oocyte within corona radiata Ruptured follicle wall Released secondary Outer oocyte surface of ovary Corona radiata Corpus albicans Corpus luteum  The Ovarian Cycle & Oogenesis 5. Formation of corpus luteum After the release of the egg, the empty follicle is called a corpus luteum corpus luteum produces progesterone Progesterone prepares the body for pregnancy If no pregnancy, the corpus luteum decomposes (~12 days after ovulation) and becomes the corpus albicans  Uterine tubes (Fallopian Tubes) Infundibulum Ampulla Isthmus Ampulla Uterine part Infundibulum Fimbria Uterus Fimbriae Fig 27.14  The Uterus Provide protection for the embryo Provides nutritional support for the embyro Provides a means to remove waste produced by the embryo Overall size Pear-shaped 7.5 cm long, 5 cm diameter 30–40 g The Uterus  Suspensory ligaments of the Uterus POSTERIOR Sigmoid colon Uterosacral ligament Suspensory ligament of ovary Cardinal ligaments Ovary Uterus Urinary bladder Round ligament of uteru s ANTERIOR Fig 27.11  Suspensory ligament of ovary Fundus of uterus Ovarian artery and vein Body of Mesovarium Ovary uterus Ovarian ligament Uterine Round ligament cavity of uterus Broad ligament Uterine artery and vein Internal os Isthmus of uterus Cervix Cervical canal Vaginal artery External os Vaginal (external orifice) rugae Vagina Fig 27.15  The Uterine Wall Three layers 1. Endometrium 2. Myometrium: longitudinal, circular, & oblique smooth muscles 3. Perimetrium Fig 27.15  Histology of the Uterus Endometrium: Functional layer – closest to the uterine cavity – Contains uterine glands – Undergoes cyclic changes due to hormones Basilar layer – closest to the myometrium – The Uterine Wall Uterine Endometrium Myometrium Perimetrium cavity Radial artery Arcuate artery Uterine artery a A diagrammatic sectional view of the uterine wall Fig 27. 16  The Uterine Wall Straight artery Radial artery Endometrium Simple columnar Spiral artery epithelium Functional layer Basilar layer Uterine glands b A Sectional view of the endometrium and its arterial supply Fig 27.16  The Uterine cycle The uterine cycle is the menstrual cycle (28 days) – Consists of three phases 1. Proliferative phase 2. Secretory phase 3. Menses  The uterine cycle Menarche – This is the first uterine cycle at puberty 1. Proliferative phase – Endometrial lining thickens preparing the body for the implantation of a fertilized egg – Same time as primary and secondary follicles enlarge in the ovaries 2. Secretory phase – Endometrial glands enlarge and blood vessels elongate – Begins at time of ovulation – An egg is ready to implant (if an egg is present) The uterine cycle Proliferative phase. Secretory phase Uterine glands UTERINE CAVITY Secretory phase LM × 52 Proliferative phase LM × 66 c Secretory phase. The functional layer is now so thick that at a magnification comparable to that of part (a) or part (b) you cannot capture the entire width of the endometrium in one image.  Perimetrium The uterine cycle Endometrium Myometrium 3. Menses Cervix Begins due to a decrease in progestin and estrogen levels (end of ovarian cycle) Uterine UTERINE CAVITY glands Cause constriction of blood vessels Causes a loss of the excess endometrial cells (loss of functional layer) This is menstruation Menopause = Menses LM × 63 Fig 27.17 a Menses.  Cervix Cervical canal; lower ends of uterus; top of vagina Os – Opening; normally width of straw; can expand!  The vagina Three major functions Passageway for elimination of menstrual fluids Receives the penis and holds spermatozoa before they enter the uterus Serves as a passageway for the fetus during vaginal birth  The vagina Extends from the cervix of the uterus to the external genitalia Vagina is approximately 7.5–9 cm in length Cervix projects from the uterus into the vaginal canal The edges of the cervix form recesses called the fornix The urethra, vaginal canal, and rectum are in close proximity to each other  The vagina Major Components of the Female Reproductive System Ovarian follicle Gonad Ovary Rectouterine Uterine tube pouch Sigmoid colon Uterus Vesicouterine pouch Perimetrium Myometrium Urinary bladder Endometrium Urethra Cervix Pubic symphysis Accessory Glands Vagina Rectum Paraurethral glands Greater vestibular gland Anus External Genitalia Labium minus Clitoris Labium majus Fig 27.10  Histology of the Vaginal Wall Stratified squamous epithelium Fornix (nonkeritinized) Vaginal Blood vessels artery Lamina propria Vaginal vein Rugae Vaginal Hymen canal Lumen of vaginal canal Greater vestibular gland Bundles of smooth muscle fibers Labia minora Vestibule The vaginal wall LM × 27 Fig 27.19  The External Genitalia Vulva: The entire genitalia area Vestibule: The opening into the vagina surrounded by the labia minora Clitoris: Contains erectile tissues Prepuce: skin surrounding the clitoris Labia majora and mons pubis: Forms the lateral and superior edges of the vestibule Hymen (when present): elastic epithelial fold External Genitalia Mons pubis Clitoris Prepuce Glans Vestibule Urethral opening Labium minora Hymen (torn) Vaginal entrance Labium majora Greater vestibular Gland (Bartholin glands) Anus a An inferior view of the female perineum Fig 27.20  Bartholin glands Small pair to right/left of vagina Function = not really well known – Lubrication just before orgasm – Mucus secretion @ arousal, to make initial contact more comfortable  Vestibular bulbs bulbs of clitoris erectile tissues Similar to spongy bodies of penis  Skene’s glands a.k.a. paraurethral glands Sometimes called the female prostate – Secretes a similar fluid – Duct empties into urethra Size varies considerably among women some sensitive region on wall of vagina Extremely pleasurable for some G-spot (Grafenberg spot) The Mammary Glands Pectoralis major muscle Pectoral fat pad Suspensory ligaments 1. Lobules of mammary glands 2. Lactiferous duct Areola Nipple 3. Lactiferous sinus Fig 27.21 The end…. GOODLUCK!!!