The Reproductive System Anatomy & Physiology, Lecture notes of Medical Sciences

Download The Reproductive System Anatomy & Physiology and more Lecture notes Medical Sciences in PDF only on Docsity! Essentials of Human Anatomy & Physiology Mr. Hildebrandt The Reproductive System Anatomy & Physiology Reproductive System Functions • Ensure the continuation of the human species • Designed to produce, store & transport gametes (sex cells). • Gonads (sex organs) carry out meiosis to produce gametes: • Testis – Male gonads produce sperm • Ovaries – Female gonads that produce eggs Male Gamete Production • Spermatogenesis (sperm production) begins in the testis and takes 64-72 days • Each lobule of the testis contains 1-4 seminiferous tubules • Interstitial cells in testis produce androgens such as testosterone Sperm Cell – The male gamete • The only human flagellated cell • DNA is found in the head • Are produced from puberty until death Male Reproductive System • Testis – male gonad • Epididymis • Ductus (vas) deferens • Seminal vesicles • Prostate gland • Bulbourethral (Cowper’s) gland • Urethra Female External Genitalia • Vaginal orifice • Vestibule • Clitoris • Labia majora • Labia minora Female Gamete Production • Oogenesis (egg production) takes place in the ovaries • The total supply of eggs are present at birth • Ability to release eggs begins at puberty • Reproductive ability ends at menopause • Oocytes (female gamete) are matured in developing ovarian follicles Ovarian Follicle Stages • Primary follicle – contains an immature oocyte • Graafian (vesicular) follicle – growing follicle with a maturing oocyte • Ovulation – when the egg is mature the follicle ruptures • Occurs about every 28 days • Ruptured follicle transforms into corpus luteum Menstrual (Uterine) Cycle • Pituitary gland secretes follicle stimulating hormone (FSH) into bloodstream. • Ovaries recognize FSH & produce a follicle (egg & supportive cells). • Follicle secretes estrogen into bloodstream. • Estrogen leads is recognized by: • Pituitary gland which stops secreting FSH • Uterus which begins to thicken its lining • Pituitary gland now secretes lutenizing hormone (LH) into bloodstream. More of the Menstrual Cycle • The ovary recognizes LH and releases an ovum – ovulation. • Supportive cells left behind in the ovary (now called the corpus luteum) secrete progesterone into the bloodstream. • Progesterone is recognized by: • Pituitary gland which stops secreting LH • Uterus which rapidly thickens its lining • If no fertilization occurs, corpus luteum breaks down & stops making progesterone • Without progesterone, the extra uterine lining is shed - menstruation | Hormonal Control of the Ovarian and Uterine Cycles 2 OO O98 ate Ovulation ts ating follicle foll luteum orpus luteum L | I Follicular Ovulation Luteal phase (Day 14) phase (c) Ovarian cycle Endometrial Menstrua layers: flow Functional layer Basal layer A a 25 : | me nstru: a oe eal a vehi | sna (d) Uterine cycle | Human Fertilization Childbirth (Partition) • Labor – the series of events that expel the infant from the uterus • Initiation of labor: • Estrogen levels rise • Uterine contractions begin • The placenta releases prostaglandins • Oxytocin is released by the pituitary • These hormones produce contractions Human Mammary Glands • Modified sweat glands: • Alveolar glands – clusters of milk producing glands within lobules • Lactiferous ducts – connect alveolar glands to nipple • Present in both sexes, but only function in females • Stimulated by sex hormones (mostly estrogens) to increase in size