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Lab Activity 33

Lab Activity 33 . Anatomy of the Reproductive System. Portland Community College BI 233. Scrotum. Sac of skin and superficial fascia that hangs outside the abdominopelvic cavity at the root of the penis Contains paired testicles separated by a midline septum

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Lab Activity 33

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  1. Lab Activity 33 Anatomy of the Reproductive System Portland Community College BI 233

  2. Scrotum • Sac of skin and superficial fascia that hangs outside the abdominopelvic cavity at the root of the penis • Contains paired testicles separated by a midline septum • Its external positioning keeps the testes 3C lower than core body temperature

  3. Penis • Internal penis: The urethra and three cylindrical bodies of erectile tissue • Corpus spongiosum: Surrounds the urethra and expands to form the glans and bulb of the penis • Corpora cavernosa: Paired dorsal erectile bodies bound by fibrous tunica albuginea • Crura: anchors the penis to the pubic arch

  4. Penis Histology

  5. Testicles • Seminiferous tubules: • Produce the sperm • Converge to form the tubulus rectus • The straight tubulus rectus conveys sperm to the rete testis • From the rete testis, the sperm: • Leave the testis via efferent ductules • Enter the epididymis • Surrounding the seminiferous tubules are interstitial cells

  6. Testicle

  7. Seminiferous Tubules“Sperm Factory” • Interstitial cells (Leydig cells) • In the soft connective tissue surrounding the seminiferous tubules. • Produce Testosterone when stimulated by LH

  8. Seminiferous Tubules“Sperm Factory” • Sertoli Cells (sustentacular cells) • Support and nourish the spermatogenic cells • Completely surround the spermatic cells undergoing meiosis • Creates the blood-testes barrier • Stimulated by FSH • Secretes: • Androgen binding protein (ABP): Concentrates testosterone in the seminiferous tubules • Inhibin: Released when sperm production is too high (slows it down). Inhibits the secretion of FSH and GnRH

  9. Seminiferous Tubules

  10. Seminiferous Tubules Histology

  11. Epididymis • Epididymis: Storage and maturation area for sperm • Its head joins the efferent ductules and caps the superior aspect of the testis • The duct of the epididymis has stereocilia that: • Absorb testicular fluid • Pass nutrients to the sperm • Nonmotile sperm enter, pass through its tubes and become motile (propelled by peristalsis) • Upon ejaculation the epididymis contracts, expelling sperm into the ductus deferens

  12. Ductus Deferens and Ejaculatory Duct • Ductus Deferens: Runs from the epididymis through the inguinal canal into the pelvic cavity • Ampulla: The expanded terminal end on posterior bladder • Ejaculatory Duct: Formed from the ampulla and the duct of the seminal vesicle • Most of it is in the prostate gland • Propels sperm from the epididymis to the urethra

  13. Ampulla Seminal vesicle Ejaculatory Duct

  14. Spermatic Cord • Contains the structures running from the testicles to the pelvic cavity. • Passes through the inguinal canal • Contents: • Vas Deferens • Nerves • Blood Vessels

  15. Accessory Glands: Seminal Vesicles • Lie on the posterior wall of the bladder and secrete 60% of the volume of semen • Seminal fluid: • Fructose: provides energy for the sperm. • Fibrinogen: helps turn semen into a bolus that can be readily propelled into the vagina. • Prostaglandins: decrease cervical mucus viscosity and stimulate reverse peristalsis of the uterus. • Join the ductus deferens to form the ejaculatory duct

  16. Posterior Bladder

  17. Accessory Glands: Prostate Gland • Doughnut-shaped gland that encircles part of the urethra inferior to the bladder • Plays a role in the activation of sperm • Enters the prostatic urethra during ejaculation • Prostatic secretions include: • Citrate: is a food source (TCA cycle) • Proteolytic enzymes: acts to "decoagulate" the semen that was coagulated by seminal vesicle secretions, which helps the sperm begin their journey once inside the vagina

  18. Bulbourethral Glands (Cowper’s Glands) • Pea-sized glands inferior to the prostate • Produce alkaline mucus prior to ejaculation that neutralizes traces of acidic urine in the urethra

  19. Sperm Summary • Produced: Seminiferous tubules • Stored: Epididymis • Transported through epididymis by rhythmic peristaltic contractions as they mature • EpididymisVas DeferensEjaculatory duct (ampulla of vas deferens fuses with duct of seminal vesicle “ejaculatory duct”)  prostate prostatic urethra (then passes the bulbourethral gland) membranous urethrapenile urethra

  20. Female External Genitalia • Mons pubis: fatty pad over the pubic symphysis • Labia majora & minora: folds of skin encircling vestibule where find urethral and vaginal openings • Clitoris: small mass of erectile tissue • Bulb of vestibule: masses of erectile tissue just deep to the labia on either side of the vaginal orifice • Perineum: Area between the vagina and anus

  21. Female External Genitalia Perineum

  22. Vagina • Thin-walled tube lying between the bladder and the rectum, extending from the cervix to the exterior of the body • Wall consists of three coats: fibroelastic adventitia, smooth muscle muscularis, and a stratified squamous mucosa • Mucosa near the vaginal orifice forms an incomplete partition called the hymen • Vaginal fornix: upper end of the vagina surrounding the cervix

  23. Bartholin’s Glands (aka: Vestibular Glands) • The Bartholin's glands are located on each side of the vaginal opening. • They secrete fluid that helps lubricate the vagina. • Sometimes the ducts of these glands become obstructed. • Fluid backs up into the gland and causes swelling (Bartholin's cyst)

  24. Female: Lateral View

  25. Cervix • Narrow lower neck of the uterus which projects into the vagina inferiorly • Cervical canal – cavity of the cervix that communicates with: • The vagina via the external os • The uterine body via the internal os • Cervical glands secrete mucus that covers the external os and blocks sperm entry except during midcycle

  26. Endocervical canal Fornix

  27. Uterine Tubes (Fallopian Tubes) • Receive the ovulated oocyte and provide a site for fertilization • Empty into the superolateral region of the uterus via the isthmus • Expand distally around the ovary forming the ampulla • The ampulla ends in the funnel-shaped, ciliated infundibulum containing fingerlike projections called fimbriae

  28. Uterine Tubes (Fallopian Tubes) • Function: events occurring in the uterine tube • Fimbriae sweep oocyte into tube, cilia & peristalsis move it along, sperm reaches oocyte in ampulla, fertilization occurs within 24 hours after ovulation & zygote reaches uterus about 7 days after ovulation

  29. Fallopian Tube Histology Cilia sweep egg/zygote toward the uterus

  30. Uterus • Hollow, thick-walled organ located in the pelvis anterior to the rectum and posterosuperior to the bladder • Body: Major portion of the uterus • Fundus: Rounded region superior to the entrance of the uterine tubes • Isthmus: Narrowed region between the body and cervix

  31. Uterus

  32. Uterine Histology • Endometrium • Simple columnar epithelium • Stroma of connective tissue and endometrial glands • Stratum functionalis: Shed during menstruation • Stratum basalis: Replaces stratum functionalis each month • Myometrium • 3 layers of smooth muscle • Perimetrium • Visceral peritoneum

  33. Uterine Histology

  34. Endometrium Simple columnar epithelium Endometrial glands

  35. Ovaries • Each follicle consists of an immature egg called an oocyte • Cells around the oocyte are called: • Follicle cells (one cell layer thick) • Stimulated to mature by FSH from the pituitary gland • Granulosa cells (when more than one layer is present) • Thecal cells: Cells in the ovarian stroma • Thecal & granulosa cells work together to produce estrogen

  36. Follicle Development • Primordial follicle: one layer of squamous-like follicle cells surrounds the oocyte • Primary follicle: two or more layers of cuboidal granulosa cells enclose the oocyte • Secondary follicle: has a fluid-filled space between granulosa cells that coalesces to form a central antrum • Graafian follicle: secondary follicle at its most mature stage that bulges from the surface of the ovary • Corpus luteum : ruptured follicle after ovulation

  37. Ovary Histology

  38. Ovary Histology

  39. Primary Follicle 1° Oocyte(arrested in prophase I) Nucleus Primordial follicle Zona pellucida Thecal cells Granulosa cells

  40. Secondary Follicle

  41. Graafian Follicle Fluid filled antrum Oocyte 2° Granulosa cells Stalk Corona radiata Zona pellucida

  42. Ovulation • LH from the pituitary gland will cause the Graafian follicle to rupture • The oocyte will be released (ovulation) • The follicle is now a corpus luteum • Secretes estrogen and progesterone

  43. Mammary Glands • Modified sweat glands that produce milk (lactation) • Amount of adipose determines size of breast • Milk-secreting glands open by lactiferous ducts at the nipple • Areola is pigmented area around nipple • Suspensory ligaments suspend breast from deep fascia of pectoral muscles (aging & Cooper’s droop)

  44. Breast

  45. Breast • Prolactin from the pituitary gland stimulates the synthesis of milk • Oxytocin from the posterior pituitary gland stimulates milk ejection

  46. Lymphatic Drainage • Lymph nodes draining the breast are located in the axilla.

  47. Lab Activity 34 Gametogenesis

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