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describe the structure and fxn of the male external genitalia:
- scrotumpouch of skin, muscle, connective tissue
- contains: 2 testes (compartmentalized), spermatic cord (vessels, nerves, ductus deferens), creamaster muscle, ductus deferens, epididymus, testes, dartos muscle
- fxn: holds testes, keeps @ 35 degrees celcus
- creamaster musclewhen cold, contracts
- brings testes closer to the body, when warm relaxes
- dartos musclesame as creamaster muscle
- contraction decreases surface area
- decreases heat loss
- pampiniform plexusnetwork of veins
- acts as countercurrent heat exchanger
- removes heat from arterial blood (makes 2 degrees cooler
- penisdeposit semen into vagina
- 3 types of erectile tissue - tiny blood sinuses fill during erection - corpus cavernosum, corpus spongiosum, prepuce
- prepuce - removed during circumcision
- dorsal side = anterior
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list the fxn of the reproduction system:
production of gametes
- male: produces sperm + inseminate women
- female: produce eggs + receive sperm, shelters embryo + nourish offspring
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describe the primary and secondary sex organs of males and females:
- primary organs (gonads): male - testes, female - ovaries
- secondary organs: necessary for reproduction, male - ducts, glands, penis, female - uterine tubes, uterus, vagina
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describe the structure and fxn of the testes including sertoli cells and leydig cells:
fxn: production of sperm + testerone
- structure
seminiferous tubules: sperm production (250M long) - rete testis: network of tubes, sperm is partially mature here, sperm move inside by fluid pressure, DO NOT SWIM THERE
- leydig interstial cellsproduce testerone
- sertoli cellsprotects developing sperm
- forms blood/teste barrier
- prevents immune/chemcial destrcution
- promote sperm development - provides nutrients, growth factors, removes wastes, provides fluid to move sperm along
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trace the path of sperm from the site of production thru the spermatic duct system to the exterior of the body:
- efferent ductules: ~ 12 cillia to propel sperm along
- epididymis: sperm maturation (~20 days), sperm storage (40-60 days)
- ductus deferens: most sperm stored
- ejactuatory duct: passes thru prostate
pathways: urethra - shared by urinary + reproductive systems (cant pass at the same time)
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describe the structure and fxn of the accessory glands (seminal vessicles, prostate gland, bulbourethral gland) including their contributions to semen and their order of contraction:
- seminal vessicles2x
- size of little finger
- yellowish secretions (60% of semen)
- prostate glandsize of walnut
- 30% of semen, think milky secretions
- cancer - 2nd highest in males, high cure rate if found early
- bulbourethral (cowpers) glandempties ito urethra (inner end of penis)
- produces clear, slippery fluid during arousal
- lubriacates head of penis
- neutralizes acidity of any residual urine
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review spermatogenesis including the stages of cell progression from spermatogonia into mature sperm:
- net result: 4 daughter cells (sperm), each haploid, 23 unpaired chromosomes
- germ cells > spermatogonia > primary spematocytes > 1st meiotic division > secondary spermatocytes > 2nd meiotic division > spermatides > differentiation - spermatoza **1st meiotic division provides genetic diversity (prophase)
- some spermatogonia remain behind as stem cells
- basement membrane of seminiferous tubules
- type A: replicates
- type B: differeniates - spermatogonium - outside the blood teste barrier, provides protection against own antibodies, sustentacular cell-sertoli cell
- primary spermatocyte - inside BTB before meiosis I
- secondary spermatocyte - meiosis II
- spermatide - sprouts tail, loses cytoplasm/bridges
- spermatogensis - 4 spermatids result/spermatogonia (young adult 300K/min, 600 ml/day)
*migrate to center lumen dividing + differenating, takes ~ 74 days
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describe the structure of mature sperm and the fxn of its components:
- acrosome: contains enzymes needed for fertilization
- the head: all most all nucleus
- midpiece of the tail: large, mumerous mitochondria, energy for motility
- endpiece of tail: propulsion ~ 3mm/min, 30 mins till fallopian tube
- final maturation/activation occurs in the female
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discuss the formation of semen and describe the fnx of the components of semen:
seed, ~ 2-5 ml/ejaculation
- 60% seminal vessicle fluidproseminogelin, prostaglandins, alkaline phosphates (enzymes), fructose
- 30% prostate fluidclotting enzymes, serine protease (enzyme), alkaline mucus
- 10% sprem/spermatic duct serections50-120 M/ml
- trace amount of bulbouretheral fluid
- seminoglein: clotting enzyme + proseminogelin (precursor), keeps semen in vagina
- serine protease: aka PSA, secreted 30 min later, breaks down seminogelin, liquifies semen, activating sperm
- prostagladins: thins vaginal mucus, easier sperm motility, stimulates uterine contractions (helps sperm move up tubes)
- alkaline phosphate: pH buffer (pH changes from ~ 4 to 7.5), helps activate sperm
- fructose: sperm energy source
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identify the target cells and effects of GnRH, FSH, LH, and inhibin:
- spermatogensis: activation requires testerone + FSH, to shut down requires inhibin
- hyopthalamus: secretes GnRH > GnRH in hypothalmo-pituitary protal vessicle> anterior pituitary secretes FSH, LH> FSH stimulates sertolie cell - stiumulates spermatogensis, and produces inhibin (negative feedback on FSH only) > LH stimulates leydig cells- testoerone, stimulates sertoli cell and engative feedback on LH and Hypothalamus
- 2ndary sex characteristics: reproductive tract + other ograns repsond to testerone
- inhibin decreases FSH (NOT LH)
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list the fnx of testosterone:
- testosterone
1st trimester: fertilization - 2nd trimester: birth (increase)
- 13 yrs/puberty: increase GnRH, LH, testosterone
- adult: level secretion
- 60 yrs: decrease secretion, decrease libido, sperm motility
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list the fxn of testicluar andorgens
testciular androgensgrowth and maintence of sex organsspermatogensisbody growth - protein synthesis, especially bone/muscle/vocal cordspubic/axiallary/facial hair , darker, thicker skinRBCs/metabolismlibido (sex drive)+ aggression
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desribe the phases of the male sexual cycle including regulation by the nervous system:
- emotions: powerful part of stimulation
- increased HR, BP, ventilation
- stimulation > increased PSNS > nitrous oxide - vasodilation (increase blood flow) > trabecular muscle of erectile tissue, relaxes; allows for engorgement of erectile tissue > penis becomes erect
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Which of the following are the male primary sex organs? (Choose all that apply)
seminal vesicles
prostate
testes
scrotum
penis
vas deferens
testes
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Which of the following are mechanisms used by the body to COOL the testicles? (Choose all that apply)
relaxation of dartos muscle
contraction of the cremaster muscle
decreased blood flow
countercurrent heat exchange
- relaxation of dartos muscle
- countercurrent heat exchange
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Which of the following produce testosterone?
Leydig cells
hypothalamus
sperm cells
anterior pituitary
Sertoli cells
Leydig cells
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Which of the following produces fluid to neutralize urine in the urethra?
efferent ductules
sustentacular cells
bulbourethral glands
seminal vesicles
prostate gland
bulbourethral glands
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In spermatogenesis, before meiosis I occurs, the __________ must first move inside the blood-testes barrier. At the end of meiosis II a total of four ________ are produced.
spermatids, spermatogonium
secondary spermatocytes, spermatids
spermatogonia, primary spermatocytes
spermatids, mature sperm cells
primary spermatocytes, spermatids
primary spermatocytes, spermatids
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Which of the following ensures semen does not flow out of the vagina?
a large sperm count
vaginal mucus
serine protease
seminogelin
anti-gravity skivvies
seminogelin
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Which of the following suppresses FSH secretion?
inhibin
follicle stimulating hormone by negative feedback
lutenizing hormone
androgen-binding protein
gonadotropin-releasing hormone
inhibin
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Which of the following stimulates the production of pubic hair and facial hair?
testosterone
inhibin
estrogen
dihydrotestosterone
Tabasco
dihydrotestosterone
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Erectile tissues become engorged with blood when the _______ triggers the release of the signaling molecule _______, which causes relaxation/dilation of the arteries in the penis.
somatic nervous system; seminogelin
SNS; serine protease
PSNS; nitric oxide
PSNS; prostaglandin
SNS; bicarbonate
PSNS; nitric oxide
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