reproductive system notes

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Reproductive
System
Honors Anatomy &
Physiology
Male Anatomy
Structures & Their functions
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External Genetialia:
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Penis – copulatory organ
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Shaft, glans (enlarged tip), prepuce (foreskin)
Erectile (spongy) tissue – connective tissue, smooth muscle, and vascular spaces
Erection – sexual arousal triggers parasympathetic release of NO causing
arterioles to dilate, engorgement restricts drainage
Testes (gonads)-1.5” x 1” sperm & testosterone production
Scrotum – maintain testes temp 3oC lower than body temp (retractable)
Duct System (sympathetic control over ejaculation)
 Epididymis –20 ft long, 20 days for sperm to become motile, may
be stored for months (ejaculated by smooth muscle or
phagocytized)
 Ductus deferens – 18” long, thick smooth muscle
 Ejaculatory duct – through the prostate and empties into urethra
 Urethra – both urine & sperm (has priority!)
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3 regions: prostatic urethra, membranous, spongy
Semen
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Semen – milky white, sticky secretion of sperm
& secretions
2-5mL per ejaculation
20-150milliom sperm per mL
Catabolism of fructose provides ATP for
flagella
Prostaglandins stimulate uterine peristalsis
Accessory Glands
 Seminal vesicles – 60% of semen: yellow,
viscous alkaline fluid w/fructose, ascorbic
acid, prostaglandins enhancing sperm
motility
 Prostate Gland – 30% of semen: milky
acidic fluid w/enzymes to activate sperm
 Bulbourthral glands – pea sized glands
secrete a thick clear mucus to neutralize
acidic urine in urethra “pre-ejaculate”
Structure of the testis
 Surrounded
by 2
membranes:
 Tunica vaginalis
 Tunica albuginea
 Divided into 250-300
lobules
 Ea/w 1-4 seminiferous
tubules (sperm production)
 Surrounded by myoid cells
– contract to squeeze
sperm out of testis into rete
testis
Spermatogenesis
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Begins @ age 14
Makes ~400million
sperm/day
Spermatogonia –
divide by mitosis
@puberty some
become primary
spermatocytes
generating
secondary
spermatocytes
Producing non motile
spermatotids
Female Anatomy
Female External Genitalia
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Vagina – 3-4” birth canal &
copulation organ
 3 layers: outer fibroelastic,
smooth muscle, ridged mucosa
 Acidic pH – antimicrobial but
hostile to sperm
 Hymen – vascular membrane in
virgins
Mons pubis – fatty ridge
Labia: majora & minora – enclose
the vestibule or entrance
Vestibular glands – secrete mucus
Clitoris – innervated erectile tissue
hooded by prepuce
Ovaries
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Produce Ova (eggs) & Sex hormones
Ovarian ligament anchor to uterus & suspensory ligament
to pelvic wall
Ovarian follicles ea/contains oocyte surrounded by follicle
cells
Primordial follicle – 1 layer cells surround oocyte
Primary follicle – 2 + layers of cells
Secondary follicle – fluid filled cavity appears
Graafian follicle – follicle bulges from ovary surface,
mature oocyte
Ovulation – oocyte ejected from ovary
Corpus luteum – follicle degenerates into scars/pits
Oogenesis
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Fetal period – oogonia divide by
mitosis
 (7 million) Primary oocytes in
primary follicles begin meiosis I,
and stall in prophase I (2 milion)
Puberty 250,000 oocytes remain
 1 selected every 28 days to
complete meiosis I, first polar
body undergoes apoptosis,
secondary oocyte is
suspended in metaphase II
when ovulated
 <500 released over 40 years
After fertilized, it completes
meiosis II, creating a second polar
body that deteriorates and 1
large ovum
Ovarian Cycle
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@puberty pituitary releases FSH & LH stimulating
ovaries
Follicular Phase (days 1-14)
 Menstration (days 1-5 )
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endometrium sheds
Low estrogen & progesterone
Proliferative Phase (day 6-14)
  FSH & LH
  follicle growth
 estrogen (- feedback on release FSH & LH, +
feedback on estrogen)
 Endometrial lining thickens
 Cervical mucus thins
Ovulation (day 14)
  estrogen causes surge of LH & FSH, then
drops
 Ovary expels 2o oocyte w/corona radiata
 Mittlschmerz – abdominal pain due to ovarian
wall stretching
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21-40 days, avg 28 days)
Luteal /Secretory Phase (days 14-28)
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estrogen
 progesterone (thickens endometrium)
Corpus luteum degenerates
Female Duct System
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Uterine (fallopian) tubes
 Receive ovulated oocyte
 About 4” long
 Fimbraie – ciliated finger like projections on distal end
create current to capture oocytes
 Infundibulum – funnel shaped structure
 Smooth muscle (peristalysis) & mucosa ciliated lining
Uterous (womb)- nourish fertilized ovum
 Inverted pear in size and shape
 3 regions: fundus, body, & cervix
 3 layers of wall:
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Perimetrium – outermost layer
Myometrium – smooth muscle
Endometrium – 2 layers of mucosal lining (inner layer sheds)
Menopause
 20’s
reproductive peak
 30’s ovarian function
(quality of oocytes)
declines, still ~100,000
oocytes left
 By 50, only ~3 oocytes left
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Estrogen production
declines
Menstrual periods erratic &
shorter, until ovulation &
menstruation ceases
Menopause reached after
1 year w/o menstruation
Mammary Glands
 Produce
milk by modified
sweat glands
 Areola – ring of pigmented
skin surrounding nipple
 Ea gland/ 15-25 lobes
consisting of lobules
containing alveoli that
produce milk
 Milk passes into lactiferous
ducts which open at nipple