Chapter 28 Reproductive Anatomy and Functions

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Chapter 28Reproductive Anatomy and Functions
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• Objective 1 list functions of male reproductive
  tract
• Produce and maintain secondary masculine
  characteristics
• Production of sperm
• Delivery of sperm to female reproductive tract

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• Objective 2 Describe the endocrinology,
  genetics and anatomy of male fetal development
• Fertilization of ova by Y carrying sperm
• 30 days post-conception TDF (Testicular
  Determining Factor) gene in SRY (Sex determining
  Region of Y) of Y chromosome activates
• Fetal gonads produce testosterone (an androgen)
  and MIF (Müllerian-inhibiting factor)
• Cells with androgen receptors respond and
  reproductive tract develops as a male. Also
  turns off genes specific for female reproductive
  structures

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Fig. 28.29
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Fig. 28.30
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• 1. Testis-determining factor is found in or on
• A) the Y chromosome.
• B) the X chromosome.
• C) the gonadal ridges of the embryo.
• D) the fetal testis.
• E) the sustentacular cells of the testis.

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• Sisters with androgen insensitivity due to
  abnormal receptor gene.
• Their genotype is
• XO
• XX
• XY
• XXY
• XXX
• XYY

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• Testes develop near kidneys
• Gubernaculm shortens and draws them through
  inguinal canal into scrotum late in gestation
• Should be fully descended by 1 month old

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Fig. 28.03a

• Overall Objective Locate and give functions for
  all structures of the reproductive tract and
  accessory sex glands.

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• Spermatic cord and scrotum objective describe
  structure and functions
• Scrotum
• Dartos M, temperature regulation
• Septum
• Median raphe
• Spermatic cord
• Vascular structure (spermatic artery and
  pampiniform plexus)
• Cremaster Muscle
• Vas deferens
• Autnomic and somatic nerves
• Lymphatics
• Inguinal canal

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Fig. 28.04
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• Testes Objective describe structure, cell types,
  hormones produced and functions of testes
• Tunics external to gland
• Sperm produced in seminiferous tubules
• Spermatagonium (capable of mitosis)
• Primary spermatocytes
• Secondary spermatocytes
• Spermatids
• Sperm
• Seminiferous Tubules also contain Sertoli cells
• Form blood-testes barrier
• Secrete inhibin (endocrine feedback for sperm
  production)
• Various support functions
• Interstitial (Leydig) cells produce testosterone

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Fig. 28.05b

• Tunics

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Fig. 28.05a

• Note location of seminiferous tubules within
  testis, connections with epididymis and vas
  deferens

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Fig. 28.06

• Tubular structure related to spermatogenesis

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Fig. 28.07

• Review spermatogenesis if needed. Be sure you
  know how diploid primary spermatocytes become
  haploid sperm

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Fig. 28.08

• Sperm objective describe structure (head,
  midpiece and tail) and functions of
• Flagellum
• Mitochondria
• Acrosome
• Nucleus

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• 4. The cell in spermatogenesis that undergoes
  meiosis I is
• A) a type A spermatogonium.
• B) a type B spermatogonium.
• C) a primary spermatocyte.
• D) a secondary spermatocyte.
• E) a spermatid.

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• Testosterone Objective Describe the effects and
  negative feed back control of testosterone.
• Testosterone control
• GnRH from hypothalamus
• LH from Ant. Pituitary
• Leydig cells
• Some converted to DHT (alternate androgen)

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• Effects of testosterone
• Prenatal
• Puberty
• Libido
• Anabolism
• Spermatogenesis objective Describe the hormone
  control.
• GnRH
• FSH plus testosterone
• Spermatogenic cell response
• Negative feedback via inhibin from Sertoli cells

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• Male duct system objective Follow path of sperm
  during ejaculation and know functions of each
  reproductive accessory gland.
• Epididymis (head and tail) connected to efferent
  ducts of testes (storage and capacitation of
  sperm)
• Vas Deferens store and propel sperm via
  peristalsis (ampulla at end)

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• Ejaculatory ducts are union of ampulla and
  seminal vesicle duct, combine sperm and seminal
  vesicle fluid during ejaculation
• Urethra passes through prostate and collects
  fluid from ejaculatory duct, prostate and
  bulbourethal glands

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• 5. All of the following play a role in
  thermoregulation of the testes except
• A) the countercurrent heat exchanger.
• B) the cremaster muscle.
• C) the pampiniform plexus.
• D) the bulbocavernosus muscle.
• E) the dartos muscle.

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• THE CENTER FOR DISEASE CONTROL has issued a
  no-nonsense, albeit
• Delayed, warning about a new, highly virulent
  strain of sexually transmitted disease. This
  disease is contracted through dangerous and high
  risk behavior.
• The disease is called Gonorrhea Lectim
  (pronounced "Gonna Re-elect him"). Many victims
  have contracted it after having been screwed for
  the past 6 years, in spite of having taken
  measures to protect themselves from this
  especially troublesome disease.
• Cognitive sequellae of individuals infected with
  Gonorrhea Lectim include, but are not limited
  to, anti-social personality disorder traits
  delusions of grandeur with a distinct messianic
  flavor chronic mangling of the English language
  extreme cognitive dissonance inability to
  incorporate new information pronounced
  xenophobia and homophobia inability to accept
  responsibility for actions exceptional cowardice
  masked by acts of misplaced bravado uncontrolled
  facial smirking total ignorance of geography and
  history tendencies toward creating evangelical
  theocracies and a strong propensity for
  categorical, all-or-nothing behavior.
• The disease is sweeping Washington. Naturalists
  and epidemiologists are amazed and baffled that
  this malignant disease originated only a few
  years ago in a Texas bush.
• Please inform any of your friends and associates
  who have been acting unusual lately.

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Accessory Sex Glands

• Seminal vesicles
• High pH to neutralize low pH of female tract
• Fructose for ATP production in sperm
• Prostaglandins for motility and may affect female
  tract to move sperm
• Seminal fluid clotting proteins to keep semen in
  female tract

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• Prostate (NOT prostrate) gland
• Surrounds prostatic urethra
• Normally hypertrophies after age 45, may infer
  with urine flow
• Contents
• Citric acid (for TCA)
• Proteolytic enzymes to break down clotting
  proteins (this includes Prostatic Specific Enzyme
  PSA used to help identify prostate cancers)

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• Bulbourethral (Cowpers) glands
• Alkaline fluid to increase pH acid urethra and
  female tract
• Mucous to prevent damage to sperm during passage

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Semen

• Combination of accessory gland fluids and sperm
• 2.5 to 5 ml volume of typical ejaculation
• About 100 million sperm/ml
• Also contains seminalplasmin, which has
  antibiotic effect on bacteria of male and female
  tracts

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• 6. Contractions of the female reproductive tract
  may be stimulated by ___ in the semen.
• A) spermint
• B) fructose
• C) prostaglandins
• D) fibrinolysin
• E) leukotrienes

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• Penis
• Three erectile structures composed of venous
  sinuses
• 2 corpora caverosum doral to urethra
• Corpora spongiosum penis surrounds urethra
• Sexual stimulation causes
• Arterial dilation (special parasympathetic effect
  and local nitric oxide)
• Fills venous sinuses
• Efferent veins are compressed keeping sinuses
  filled (turgidity and erection)
• Ejaculation via SNS reflex (closure or internal
  bladder sphincter, peristalsis of all ducts and
  release form accessory glands

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• Other penile anatomical structures
• Glans
• Corona
• Prepuce (foreskin)

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Fig. 28.12
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• 2. Men have only one ___ but have two of all the
  rest of these.
• A) bulbourethral gland(s).
• B) prostate gland(s).
• C) ejaculatory duct(s).
• D) seminal vesicle(s).
• E) corpus cavernosum (corpora cavernosa).

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• 3. Until ejaculation, sperm are stored mainly in
• A) the corpus spongiosum.
• B) the seminal vesicles.
• C) the seminiferous tubules.
• D) the prostate.
• E) the epididymis.

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On to the Female Reproductive Tract!

• Objective Describe development of female
  secondary characteristics
• Objective Describe the location, anatomy and
  ligamentous structures of the ovaries
• Objective List the chronology of follicle
  development

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Fig. 28.13a
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Fig. 28.13b
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Fig. 28.14

• Ovarian and broad ligaments

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• Follicular development
• All ova are produced before birth, begin meiosis,
  stop at prophase I, and are enclosed in a
  primordial follicle
• At puberty, surviving follicles become primary
  follicles, surrounded by additional epithelial
  cells
• 1-2 months before each cycle, one (rarely more)
  begin to produce follicular fluid, complete
  meiosis 1 and become secondary follicle
• Secondary follicle contains ova that proceeds to
  metaphase II and stops as mature (Graafian)
  follicle
• Mature follicle ruptures at ovulation
• Follicle replaced is by corpus luteum

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• 9. Estrogen causes all of the following effects
  in adolescent girls except
• A) growth of the breasts.
• B) growth of the pubic and axillary hair.
• C) vaginal metaplasia.
• D) endometrial mitosis.
• E) fat deposition.

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Fig. 28.T01
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Fig. 28.15
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Fig. 28.16a
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Fig. 28.16b
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Fig. 28.17

• Fertilization is required to complete meiosis II
  and production of second polar body

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• Reproductive anatomy Objective Now follow ova
  through reproductive tract. Note location of
  fertilization.
• Uterine (oviducts or Fallopian) tubes
• Infundibulum (funnel like opening)
• Fimbriae (fingers) sweep ova into oviduct
• Lined by ciliated epithelium to move ova to
  uterus
• As secondary oocyte only lives 24 hours, it must
  be fertilized here, then becomes a zygote or
  dies.
• Transport to uterus takes 5-6 days

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Fig. 28.18
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Fig. 28.19
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• Uterus objective Describe the histology and
  structure of the uterus and cervix
• Structure
• Fundus
• Body and cavity
• Cervix, cervical canal, internal and external os
• Broad and round ligaments

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• Histology
• Serosa
• Myometrium,
• Endometrium with uterine glands and simple
  columnar epithelium. Two layers Stratum
  functionalis responds to hormone levels and
  sloughs during menstruation. Stratum basalis
  regenerates stratum functionalis.
• Vascular uterine artery and vein
• Cervix produces mucous that protects sperm and
  form cervical plug during pregnancy

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• Vagina
• Functions as seminal receptacle, menstrual fluid
  outflow and birth canal
• Fornix at cervical attachment (location for
  diaphragm insertion)
• Mucosa maintains low pH as protection against
  bacteria
• Muscularis of smooth muscle
• Hymen partially closes inferior vagina

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Fig. 28.21
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• Vulva (external genitals)
• Mons pubis
• Labia majora
• Labia minor
• Clitoris (erectile tissue and sensory nerves)
• Prepuce
• Vestibule
• Opening to vagina (vaginal orifice and hymen)
• Urethral orifice
• Vestibular glands (produce mucous lubricant
  during sexual stimulation)
• Bulb of vestibule (analogous to corpus
  spongiosum)

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Fig. 28.22

• Perineum may be incise (episiotomy) during child
  birth

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Fig. 28.23
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• Objective Describe structure of mammary glands,
  hormone control of milk production and ejection.
• Mammary Glands
• Function to synthesize, secrete and eject milk
• Modified sudoriferous glands
• Alveoli within lobes of glands produce milk,
  which passes into mammary duct and lactiferous
  sinus
• Lactiferous ducts connect lactiferous sinus with
  nipple
• Suspensory (Coopers) ligaments between skin and
  deep fascia of pectoralis m.

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Fig. 28.24
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• Hormone control
• Synthesis and secretion stimulated by prolactin
  of anterior pituitary (controlled by PRH from
  hypothalamus) with help from estrogen and
  progesterone
• Ejection stimulated by oxytocin from posterior
  pituitary
• Combination is lactation

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• 11. Mammary gland development and lactation
  depend on all of the following hormones except
• A) estrogen.
• B) progesterone.
• C) insulin.
• D) prolactin.
• E) All of these are required

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• Female reproductive cycle objective Describe
  the pituitary, ovarian and uterine events of the
  three phases of the cycle. Include the levels of
  various hormones and how they affect the phases.
• Hormone Control of Ovarian and Uterine Activity
• Low ovarian activity stimulates hypothalamus to
  secrete GnRH (gonadotropin releasing hormone)
  which stimulates the ovary as described on day
  1-5). Day one is recognized as the first day of
  menstrual flow.

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• Menstrual Phase (Day one to five of cycle)
• Endocrine activity Little (low progesterone)
• Ovarian Cycle without pregnancy, CL of previous
  cycle degenerates, reducing progesterone levels
• Uterine cycle Low progesterone levels cause
  release of prostaglandins, causing
  vasoconstriction of spiral arteries to
  endometrium and death of most of endometrium
• This causes menstrual flow of blood, mucous and
  dead epithelium

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• Preovulatory phase
• Endocrine activity increasing GnRH causes
  release of LH and FSH
• Ovarian cycle stimulated by FSH (growth of new,
  dominant follicle to become Graafian follicle and
  secretion of estrogen)
• Uterine cycle begins proliferative phase,
  stimulated by estrogen to replace lost
  endometrium

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• 8. At the time of the sexual cycle when the
  uterus is building up endometrial tissue by
  mitosis,
• A) several follicles are developing antra.
• B) the corpus luteum is shrinking.
• C) the corpus luteum is enlarging.
• D) oogonia are transforming into primary oocytes.
• E) the oocyte completes meiosis II.

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Fig. 28.27

• Ovulation (? day 14)
• Increasing estrogen causes increased sensitivity
  of follicle to LH and increased GnRH to increase
  LH secretion by pituitary gland
• LH causes rupture of follicle and release of ova
  (ovulation)

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• 7. All of the following processes are important
  in follicular development. Which one occurs
  first?
• A) FSH secretion
• B) estrogen secretion
• C) LH secretion
• D) prolactin secretion
• E) GnRH secretion

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• Postovulatory Phase
• Ovarian Cycle LH stimulates conversion of corpus
  hemorrhagicum into corpus luteum which secretes
  progesterone
• CL lasts about 14 days if no pregnancy
• Uterine cycle progesterone causes growth and
  secretion of endometrial glands (secretory
  phase). Secretions are meant to nourish embryo
• If no embryo implants in uterus, CL degenerates,
  progesterone levels decrease and new cycle begins

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Fig. 28.25
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Fig. 28.26
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• If embryo implants
• Human Chorionic Gonadotropin (HCG) is secreted by
  uterus (basis of pregnancy test as it is secreted
  in urine)
• HCG prevents degeneration of CL, maintaining
  progesterone levels, inhibiting new cycle

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Fig. 28.28
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• 2. The second half of the menstrual cycle is
  regulated largely by
• A) the corpus luteum.
• B) the corpus albicans.
• C) the corpus spongiosum.
• D) the chloasma.
• E) the placenta.

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• 3. Pregnancy tests are based on the detection of
  ___ in the urine.
• A) estrogen
• B) progesterone
• C) FSH
• D) LH
• E) HCG

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• 4. In the luteal phase of the ovarian cycle, ___
  inhibits FSH and LH secretion.
• A) inhibin
• B) HCG
• C) progesterone
• D) androgen
• E) relaxin

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• 5. In the luteal phase, all of the following
  things happen except
• A) the uterus secretes mucus rich in glycogen.
• B) the corpus luteum secretes progesterone.
• C) FSH secretion is inhibited.
• D) the endometrium nearly doubles in thickness.
• E) the endometrial cells exhibit rapid mitosis.

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• 6. Ovulation is triggered by
• A) LH.
• B) FSH.
• C) estriol.
• D) estradiol.
• E) progesterone.

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• Objective Explain the mechanism of oral,
  injectable (implantable), patch and ring
  hormone contraceptive.
• All are combinations of estrogen and pregesterone
• Maintain levels above base line at end of normal
  ovarian cycle
• Hypothalamus and anterior pituitary do not sense
  low hormone levels so no secretion of GnRH, FSH
  or LH
• Therefore no maturation of primary oocyte or
  ovulation

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• Other benefits
• Regulation of cycle length and more predictable
  time of menstrual period
• Reduced menstrual bleeding
• Reduced endometrial thickness, reduced risk of
  uterine and ovarian cancers and endometriosis