The Reproductive System - Basic Human Anatomy - Lecture Slides, Slides of Anatomy

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Developing clitoris: Labia minora Labia majora aor Te uci Compe nmin eto poe ap (a) Sexually indifferent stage Genital tubercle —— Urogenital fold Labioscrotal swelling Week 6 (b) Week 12: Urogenital folds begin to fuse in the male Developing glans of penis The Reproductive System docsity.com Reproductive Systems  Main function: propagation of the species  To achieve this goal:  Must ensure sexual maturation  Produce gametes (n).  Male and female structures are homologues:  derived from common developmental tissues docsity.com Comparison of the Female and Male Reproductive Systems  Primary sex organs called gonads.  ovaries in females  testes in males  Produce gametes which unite to form a new individual.  oocytes  sperm  Gonads produce large amounts of sex hormones which affect maturation, development, and changes in the activity of the reproductive system organs.  estrogen and progesterone in the female  androgens (esp. testosterone) in the male docsity.com Comparison of the Female and Male Reproductive Systems  Both have accessory reproductive organs  duct systems  carry gametes away from the gonads  toward the site of fertilization in females  to the outside of the body in males  Fertilization occurs when male and female gametes meet:  copulation, coitus, sexual intercourse  Restores the diploid number (2n) docsity.com Comparison of the Female and Male Reproductive Systems  Primarily nonfunctional and “dormant” until puberty.  At puberty, external sex characteristics become more prominent.  breast enlargement in females  fat distribution patterns in both sexes  pubic hair in both sexes  reproductive organs become fully functional  gametes mature  gonads secrete sex hormones  Both reproductive systems produce gametes. docsity.com Table 28.1 Ovary Clitoris Labia majora Vestibular glands Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Reproductive System Homologues Testis Glans of penis Scrotum Bulbourethral glands Produce gametes and sex hormones Contain autonomic nervous system axons that stimulate arousal and sexual climax feelings Protect and cover some reproductive structures Secrete mucus for lubrication docsity.com Perineum  Diamond-shaped area between the thighs that is circumscribed anteriorly by the pubic symphysis, laterally by the ischial tuberosities, and posteriorly by the coccyx.  2 distinct triangle bases  formed by an imaginary horizontal line extending between the ischial tuberosities of the ossa coxae.  Anterior triangle, or urogenital triangle  contains the urethral and vaginal orifices in females  contains the base of the penis and the scrotum in males.  Posterior triangle, or anal triangle  location of the anus in both sexes. docsity.com Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pubic symphysis 3 docsity.com  Mesovarium:  Double folds of peritoneum  Attaches ovaries to broad ligament  Broad ligament  Peritonium  Drapes over the uterus  Ovarian ligament  Ovary to uterus  Suspensory ligament  Ovary to pelvic wall docsity.com Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. docsity.com Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a ry Uterine tube Uterus Broad ligament Urinary bladder Round ligament (c) Superior view docsity.com Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Before Birth  The process of oogenesis occurs in a female fetus before birth. At this time, the ovary contains primordial germ cells called oogonia, which are diploid cells, meaning they have 23 pairs of chromosomes.  During the fetal period, the oogonia start the process of meiosis, but they are stopped at prophase I. At this point, the cells are called primary oocytes.  At birth, the ovary of a female child is estimated to contain approximately 1.5 to 2 million primordial follicles within its cortex.  The primary oocytes in the primordial follicles remain arrested in prophase I until after puberty. docsity.com From Puberty to Menopause  During childhood ovaries are inactive, and no follicles develop.  Atresia occurs, in which some primordial follicles regress or break down.  By the time she reaches puberty only about 400,000 primordial follicles remain.  At puberty, the hypothalamus releases GnRH (gonadotropin- releasing hormone), which stimulates the anterior pituitary to release FSH (follicle-stimulating hormone) and LH (luteinizing hormone).  The levels of FSH and LH vary in a cyclical pattern and produce a monthly ovarian cycle.  The three phases of the ovarian cycle: are the follicular phase, ovulation, and the luteal phase. docsity.com After Menopause  The time when a woman is nearing menopause is called perimenopause.  estrogen levels begin to drop, and  a woman may experience irregular periods, skip some periods, or have very light periods  When a woman has stopped having monthly menstrual cycles for 1 year and is not pregnant, she is said to be in menopause.  The age at onset typically is between 45 and 55 years  follicles stop maturing, and significant amounts of estrogen and progesterone are no longer being secreted  a woman’s endometrial lining does not grow, and she no longer has a menstrual period docsity.com Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Suspensory ligament of ovary Transverse cervical (cardinal) ligament Vagina- & (a) Posterior view . docsity.com Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Muscularis Simple ciliated columnar epithelium docsity.com The Uterus Serves Four Functions  Site for implantation.  pre-embryo implants into the inner uterine wall and becomes connected to the uterine lining  Supports, protects, and nourishes the developing embryo/fetus  forms a vascular connection with the mother’s uterine wall that later develops into the placenta  Ejects the fetus at birth after maternal oxytocin levels increase to initiate the uterine contractions of labor.  Site for menstruation.  if an oocyte is not fertilized or after a baby is expelled, the muscular wall of the uterus contracts and sheds its inner lining as menstruation docsity.com Regions of the Uterus  Fundus  Body  Isthmus  Cervix  Cervical canal  Internal os  External os docsity.com Support of the Uterus  Pelvic floor muscles  Pelvic diaphragm  Urogenital diaphragm  Round ligaments  Lateral uterus, through inguinal canal, to labia majora  Maintain anteverted position  Transverse cervical ligaments  Lateral cervix and vagina to pelvic wall  Uterosacral ligaments  Inferior uterus to sacrum docsity.com Vagina  The vagina is  thick-walled, fibromuscular tube  forms the inferior-most region of the female reproductive tract  measures about 10 centimeters in length in an adult female.  The vagina connects the uterus with the outside of the body anteroventrally  functions as the birth canal.  Also the copulatory organ of the female  Serves as the passageway for menstruation.  The vaginal wall is heavily invested with both blood vessels and lymphatic vessels.  The vagina’s relatively thin, distensible wall consists of three tunics:  an inner mucosa, a middle muscularis, and an outer adventitia docsity.com External Genitalia  The external sex organs of the female, are collectively called the vulva.  The mons pubis is an expanse of skin and subcutaneous connective tissue immediately anterior to the pubic symphysis.  covered with pubic hair in postpubescent females  labia majora  labia minora  Contain the vestibule  Urethral orifice  Vaginal oriface  Clitoris located at the anterior regions of the labia minora  glans  prepuce−an external fold of the labia minora that forms a hoodlike covering over the clitoris. docsity.com Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mons pubis Glans of clitoris Prepuce Urethral op Vestibule docsity.com Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Suspensory ligaments Adipose tissue Intercostal muscles Lactiferous Lobe Deep fascia Alveoli ——@—_—_S be Rib Lobule (b) Sagittal view docsity.com Anatomy of the Male Reproductive System  Primary organs: gonads are the testes  Accessory sex organs include:  a complex set of ducts and tubules leading from the testes to the penis  a group of male accessory glands  the penis, which is the organ of copulation docsity.com Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Ampulla of ductus deferens Seminal vesicle Ejaculatory duct Prostate gland Bulbourethral gland Anus docsity.com Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Testicular artery. eee { ¢ t Testicular vein - : 7 J i N Ze : r ia Penis “ Inguinal ligament aN Urinary bladder Superficial inguinal ring Ductus deferens Structures |P@mpiniform . : < pi ‘Spermatic cord within —_| Plexus aad Testicular artery ~ External spermatic fascia Testicular nerve Cremaster muscle within Epididymis cremasteric fascia Layers of spermatic : Internal spermatic fascia | COfd Testis Scrotum (® docsity.com Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. era " - Superficial inguinal ring Penis ~ Inguinal ligament Ductus deferens >. Spermatic cord Sificiites Testicular nerve ae . i Cremaster muscle within within __| Testicular artery Caine fasckd | spermatic | and pampiniform cord plexus Epididymis Testis: Testis docsity.com Testes  Small, oval organ  Housed in the scrotum  Produces:  Sperm  androgens.  Coverings  Serous membrane called tunica vaginalis  Parietal layer  Visceral layer.  Tunica albuginea  Forms internal septa  250 lobules per testis  Each lobule has up to 4 seminiferous tubules  Two types of cell  Sustentacular cells  Germ cells  Interior is called mediastinum testis. docsity.com Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (BD) seminiterous tubule e e *s. : Bs : : Interstitial cell ea* ®« nterstitial cells ea . ; ‘" 5 . 2 = Seminiferous i Z é tubule « we - Tubule lumen e <_< be aso) Sustentacular Sa < cells r 4 a aes « | SPO cells . ; ' ’ © { . = 4 Spermatids e* . 7 : * >a 7 Spermatogonia LM 250x docsity.com Testes  Series of tubes:  Seminiferous tubules  Straight ducts  Rete testis  Efferent ductule  Epididymis  Ductus deferens docsity.com Spermatic Cord  The blood vessels and nerves to the testis travel from within the abdomen to the scrotum in a multilayered structure called the spermatic cord.  Layers  Contain  Testicular artery  Pampiniform plexus  Autonomic nerves docsity.com Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Spermatid + Head + Midpiece t Tail (flagellum) (b) Spermiogenesis 3 docsity.com Epididymis  The epididymis is a comma-shaped structure composed of an internal duct and an external covering of connective tissue.  Its head lies on the superior surface of the testis, while the body and tail are posterior to the testis.  Internally, the epididymis contains a long, convoluted duct of the epididymis, which is approximately 4 to 5 meters in length.  Sperm must reside in the epididymis for a period of time to become mature and fully motile.  If they are expelled too soon, they lack the motility necessary to travel through the female reproductive tract and fertilize an oocyte.  If sperm are not ejected from the male reproductive system in a timely manner, the old sperm degenerate in the epididymis. docsity.com Ductus Deferens  When sperm leave the epididymis, they enter the ductus deferens, also called the vas deferens.  The ductus deferens is a thick-walled tube that travels within the spermatic cord, through the inguinal canal, and within the pelvic cavity before it reaches the prostate gland.  The ampulla of the ductus deferens unites with the proximal region of the seminal vesicle to form the terminal portion of the reproductive duct system, called the ejaculatory duct. docsity.com Seminal Vesicles  The paired seminal vesicles are located on the posterior surface of the urinary bladder adjacent to the ampulla of the ductus deferens.  Each seminal vesicle is an elongated, pouchlike hollow organ approximately 5–8 centimeters long.  It is the proximal portion of each seminal vesicle that merges with a ductus deferens to form the ejaculatory duct.  The seminal vesicles secrete a viscous, whitish-yellow alkaline fluid containing both fructose and prostaglandins.  The fructose is a sugar that nourishes the sperm as they travel through the female reproductive tract, while the prostaglandins promote the widening and slight dilation of the external os of the cervix. docsity.com Prostate Gland  A compact encapsulated organ that weighs about 20 grams and is shaped like a walnut, measuring approximately 2 cm by 3 cm by 4 cm.  Located immediately inferior to the bladder.  Secretes a slightly milky fluid that is weakly acidic and rich in citric acid, seminalplasmin, and prostate-specific antigen (PSA).  citric acid is a nutrient for sperm health  seminalplasmin is an antibiotic that combats urinary tract infections  PSA acts as an enzyme to help liquefy semen following ejaculation docsity.com Bulbourethral Glands  Paired, pea-shaped  Also called Cowper’s glands  Location:  within the urogenital diaphragm  on each side of the membranous urethra.  Each gland has a short duct  projects into the base of the penis  enters the spongy urethra.  secretory product  clear, viscous mucin (forms mucus when mixed with water).  mucin protects the urethra  serves as a lubricant during sexual intercourse. docsity.com Copyright © The McGraw-Hill Companies, inc. Permission required for reproduction or display. (a) Seminal vesicle (b) Prostate gland (® docsity.com Semen  Combination of seminal fluid from the accessory glands and sperm.  Called the ejaculate (when released during ejaculation)  normally about 3 to 5 milliliters  contains approximately 200 to 500 million spermatozoa.  Average transit time: about 2 weeks  from release of sperm into the lumen of the seminiferous tubules, passage through the duct system, and appearance in the ejaculate.  Sperm count can vary, spemen amount usually remains the same. docsity.com Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pubic Membranous symphysis urethra Bulb of penis Right crus Body (shaft of penis A of penis Corpora cavernosa Corpus spongiosum urethral orifice docsity.com Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sexually Indifferent Stage Mesonephric duct Paramesonephric duct Female duct forming the uterine tube Fused paramesonephric- ducts forming the uterus inital sinus forming rethra and inferior vagina Weeks 10-12 Male Testes Efferent ductules Epididymis forming the urethra Weeks 10-12 docsity.com Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Uterine tube Ovary Uterus Urinary bladder (moved aside) At birth docsity.com Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Urinary bladder Seminal vesicle Prostate gland Bulbourethral gland Ductus deferens Urethra Epididymis Efferent ductules Testis At birth docsity.com