Chapter 28 The Reproductive System PDF

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Chapter 28 The Reproductive System

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Pregnancy hormones o Before ovulation, FSH secretion increases, which stimulates follicles to develop and secrete estrogen, o Extrogen causes the endometrium to proliferate and the hypothalamus to increase LH secretion, which results in the LH and FSH surges prior to ovulation o The LH surge causes a follicle to mature and ovulate. The corpus luteum develops and secretes progesterone and some estrogen o The progesterone causes hypertrophy of the endometrium and has a negative feedback effect on LH and FSH secretion. The corpus luteum continues to secrete progesterone for approximately 12 days after ovulation o Which of the following hormones stimulates the synthesis of testosterone by the fetal testes?  hCG

o one hormone responsible for initiating the development of follicles is  FSH o LH surge initates  Ovulation o The hypothalamic hormone that regulates both male and female reproductive cycles is  GnRH o FSH  Primarily effects granulosa cells o FSH can make the follicle more sensitive to LH by increasing  LH receptors o Progesterone  Causes cellular hypertrophy in the endometrium 

Hormone changes during trimesters o First trimester  Human chorionic gonadotropin increases until it reaches maximum concentration near the end of the first 3 months of pregnancy and then decreases to a low level thereafter o Second trimester

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 Progesterobe continues to increase until it levels off near the end of pregnancy. Early in

pregnancy, progesterone is produced by the corpus luteum in the ovary; by the second trimester production shifts to the placenta  Early in pregnancy, estrogen is produced only in the ovary; by the second trimester production shifts to placenta o Third trimester  Estrogen increases slowly throughout pregnancy but increases more rapidly as the end of pregnancy approaches. 

Male reproduction o Anatomy  Scrotum  2 chambered sac that contains testes; separated by raphe  Dartos and cremaster muscle help regulate temperature

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 Contraction of the cremaster and dartos muscles o Pulls the testes closer to the body o Epididymis  Site of sperm cell maturation  Takes minimum of 1-2 days  Stereocillia: in pseudostratified columnar epithelium; increase surface area to facilitate absorption of fluid from lumen of the duct  The location of the testes and epididymides in the scrotum  Provides a temperature that is suitable for normal sperm development o Ductus deferens or vas deferens: passes from epididymis to abdominal cavity  Ductus, testicular artery and venous plexus, lymphatic vessels, nerves, fibrous remains of process vaginalis from the spermatic cord  Distal end of ductus deferens is enlarges as ampulla  Wall of ductus deferens has smooth muscles that exhibits peristalsis during ejaculation  The ductus deferens  Passes through the inguinal canal and enters the pelvic cavity o Testes: sperm production

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 Located outside of the body cavity because sperm require lower than body temp for development  Testes serve as both  Exocrine gland: sperm cells are the secretion  Endocrine: testosterone  Covering of testes  Tunica vaginalis: originally peritoneum, serous membrane  Tunica albuginea: thick white connective tissue. Penetrates testis to divide it into lobules. Within lobules are seminiferous tubules and interstitial (leydig) cells that secrete testosterone o The interstitial cells or leydig cells  Secrete testosterone  Tubes through which sperm move  Seminiferous tubules. Site of sperm production  Tubuli recti and rete testis: pathway to epididymis  Sperm are produced in the____ and complete maturation in the _____  Seminiferous tubules ; epididymis  Which of following hormones is produced by the testis?  Testosterone 

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Sperm cell development

o Spermatozoa produced in seminiferous tubules. At puberty, GnRH secretion increases leading to increased LH and FSH release. FSH levels promote sperm formation, FSH levels promote interstitial cells to produce large amounts of testosterone  Sustentacular (sertoli, nurse) cells nourish sperm cells and form a blood testis barrier and produce hormones  The sustentacular cells  Provide nourishment for development of sperm  Luteinizing hormone LH binds to interstitial (leydig) cells and  Increases testosterone production by the interstitial cells  Interstitial cells produce testosterone. Sustentacular cells convert it to dihydrotestosterone (DHT) and estrogen. Probably active hormones that cause sperm formation  Which of the following substance found in sustentacular cells maybe the active hormones that promote sperm cell formation?  Dihydrotestosterone and estrogen 

Penis o Three columns of erectile tissue that engorge with blood  Corpora spongiosum: surrounding spongy urethra. Forms the bulb

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 Glans penis: enlargement of corpus spongiosum o Foreskin 

Male sex act o Complex series of reflexes that result in erection of penis, secretion of mucus into urethra, emission, ejaculation

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Erection of the penis occurs when o Penile erectile tissue becomes engorged with blood

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Arrange the following events in correct sequence o Blood fills erectile tissue sinusoids and compresses veins, Arteries supplying blood to erectile tissue dilate, inflation and rigidity of erectile tissue

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Prostate gland o Emission: accumulation of sperm cells and secretions of the prostate gland and seminal vesicles in the urethra  Controlled by sympathetic centers in spinal cord  Seminal vesicles and prostate release secretions o Effects of aging: decrease in blood flow, increase in thickness of epithelial lining, decrease in functional smooth muscle cells. Possibly benign prostatic hypertrophy o Which of the following substances are found in the secretions of the prostate gland?

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 Fibrinolysin and clotting factors o Secretions produced by the prostate gland  Constitute about 30% of semen 

Nitric oxide function o What is the role of NO (nitric oxide) in the male sex act?  Dilation of blood vessels in the penis

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Oogenesis and fertilization o Oogenesis is the production of a secondary oocyte in ovaries o Oogonia are cells from which oocytes develop. The oogonia divide by mitosis to produce other oogonia and primary oocytes. o Primary oocytes are surrounded by granulosa cells and called primordial follicle o Primordial follicle becomes a primary follicle when oocyte and granular cells enlarge o Primary follicle becomes a secondary follicle and enlarges to from mature or Graafian follicle  A follicle containing secondary oocyte and a single fluid filled antrum is called a ___ follicle o Graafian  Usually only one is ovulated, others degenerate o A primary oocyte with a single layer of granulosa cells is most appropriately called  A primordial follicle o A primary follicle contains  Several layers of granulosa cells

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o As a secondary follicle enlarges  A theca or capsule is formed around it o Release of the secondary oocyte from the ovary is called  Ovulation o Which of the following is produced in the ovary and then leaves the ovary?  Secondary oocyte o The secondary oocyte completes the second meiotic division when  It is penetrated by a sperm cell o Trace the pathway of an egg as it passes through the uterine tub e  Fimbriae, infundibulum, ampulla, isthmus 

Menstrual cycle o About 28 days long o The average menstrual cycle is about ___days long; ovulation occurs on about day ___  28;14 o Phases  Menses  Proliferative or follicular phase (functional layer proliferates; follicle matures)  In endometrium, the functional layer is replaced every month during menstrual cycle.  Secretory or luteal phase (maturation and secretion of uterine glands; presence of corpus luteum)

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o Amenorrhea: absence of a menstrual cycle o Menopause: cessation of menstrual cycle o The follicular phase of the menstrual cycle is characterized by  Rapid development of ovarian follicles o Shortly after ovulation  The granulosa cells become corpus luteum cells 

Placenta o Puberty in males: before birth, placenta secretes human chorionic gonadotropin hormone which stimulates secretion of testosterone by fetal testes o Placenta produced both  Estrogen and progesterone

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cervix o cervix is a portion of the  uterus

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ectopic pregnancy o in an ectopic pregnancy  implantation does not occur in the uterus

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Post menopause o Menstrual periods become less regular, ovulation stops o LH and FSH elevated, but few remaining follicles become insensitive to LH and FSH

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o Ovaries stop producing estrogen and progesterone 

Prolactin and oxytocin

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Which of the following cell types is formed at the end of the first meiotic division? o Secondary spermatocyte

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Once GnRH is released from the hypothalamus and enters the hypothalamopopphysial portal system o FSH and LH secretions will occur

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The corpus luteum o Degenertates into the corpus alibicans If pregnancy does not occur….

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