Unit 6 Turner Male Repro

Front 1

Male repro tract consists of

Back 1

testes
prostate and seminal vesicles (primary producers of seminal fluid, with minor contributions from the cowper's and bulbourethral glands)
tubular system for sperm storage and transport consisting of the epididymis, vas deferens, ejaculatory duct, and urethra

Front 2

major compartments of the testes

Back 2

seminiferous tubules
interstitium

Front 3

seminiferous tubules

Back 3

80% of testis volume
mass of coiled loops serving as the site of spermatogenesis
large sertoli cells are closely inovolved in hormonally directed spermatogenesis

Front 4

sertoli cells

Back 4

found in the seminiferous tubules
source of many important proteins essential for normal male functions: androgen binding protein, inhibin/activin, and Mullerian inhibiting substance (MIS)

Front 5

interstitium of the testes

Back 5

connective tissue between the tubules
contains leydig cells that produce androgens

Front 6

epididymis

Back 6

continuous with testis
a tubular storage/maturation site for spermatozoa

Front 7

vas deferens

Back 7

sperm leaving the epididymis travel through the tubular vas deferens to reach the ejaculatory duct and urethra for ejaculation

Front 8

prostate and seminal vesicles

Back 8

sources of seminal fluid
first by prostate and then by the seminal vesicles
both located at distal end of vas deferens
60% from SV
20% from prostate

Front 9

seminal vesicle provides this to seminal fluid

Back 9

fructose
prostaglandins

Front 10

prostate provides this to seminal fluid

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spermine
citric acid
calcium
zinc
acid phosphatase

Front 11

prostate and seminal vesicles controlled by

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androgen which stimulates growth and can produce hyperplasia and cancer, with production of prostate-specific Ag (PSA)

Front 12

androgen effects are augmented by

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prolactin
this occurs mostly in the prostate

Front 13

benign prostatic hypertrophy (BPH)

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normal part of aging
due to testosterone ---> dihydrotestosterone --> prostate growth

Front 14

this % of individuals with BPH develop prostate cancer

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20%

Front 15

prostate cancer

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10% of all cancer deaths in males
slow or aggressive growing
DHT facilitates carcinogenesis but is not by itself carcinogenic
estrogen can be used for treatment to suppress androgen production

Front 16

PSA screening

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can help for slow growing prostate cancer
aggressive type already advanced by time screening shows it

Front 17

androgens are made where

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primarily in the testes
some in the adrenal cortex

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two most important and potent androgens and sites of production

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testosterone --> testis, adrenal
DHT --> made from testosterone in the peripheral tissues

Front 19

this androgen can be converted to equally bioactive 5alpha-androstenediol

Back 19

DHT, however DHT is predominant

Front 20

estrogens are present mostly from

Back 20

peripheral conversion of testosterone and androstenedione but play a minimal role

Front 21

Androgenic (sexual function related) effects of androgens

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stimulates spermatogenesis and libido
growth of male tract- ducts, accessory glands, penis, & scrotum
increases body and facial hair and baldness
increases vocal cord thickness and sebaceous gland secretion

Front 22

anabolic effects of steroids

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increased bone growth and epiphyseal closure
increased muscle mass and strength
increased protein anabolism

Front 23

SEs of anabolic steroids

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inhibition of gonadal function
gynecomastia
liver disease
coronary artery disease
impaired adrenal axis
masculinization of females

Front 24

andropause

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"male menopause"
testosterone deficiency
androgen treatment of andropause has increased 10x from 1998-2005; long-term effects unknown

Front 25

mediation of androgen action

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in some cells, T acts directly
in others, T must be converted to DHT by 5alpha-reductase to act

Front 26

T and DHT androgen receptors

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same receptor binds both T and DHT
binds DHT more avidly

Front 27

most DHT is due to

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intracellular conversion from T

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plasma T:DHT ratio

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10:1

Front 29

enzyme that converts testosterone to bioactive estrogens

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aromatase

Front 30

androgen actions due directly to testosterone

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gonadotropin feedback reg.
spermatogenesis
skeletal muscle and bone growth
fetal internal repro tract virilization

Front 31

androgen actions due diretly to DHT

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prostate development
SV development
fetal external genitalia virilization
sexual maturation changes at puberty

Front 32

binding proteins associated with androgens in plasma

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testosterone binding protein (TeBG) binds 44% of circulating T
TeBG levels are 2-3x higher in women than men
albumin weakly binds 54% of T
2% unbound

Front 33

binding proteins associated with androgens in the testis

Back 33

androgen binding protein is similar to TeBG but is made by sertoli cells
ABP binds T and DHT in seminiferous tubules, insuring high local concentration

Front 34

Male vs. female androgen binding proteins

Back 34

both TeBG and ABP will bind E, but with less affinity than T
the above fact and the higher TeBG levels in women account for sig. sex differeneces in T and E delivery to tissues

Front 35

spermatogenesis

Back 35

continuous process
spermatogonia replicated by cell division
100-200X10^6 sperm produced daily
new waves of spermatogonia enter cycle every 16 days and several are in progess simultaneously

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1 spermatogonia -->

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64 spermatozoa

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spermatic cycle length

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60-70 days

Front 38

sperm storage and release

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spermatozoa take 2-4 weeks to traverse epididymis to vas deferens, becoming motile and losing their cytoplasm
sperm in the vas deferens are viable for several months

Front 39

one ejaculate contains

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200-400x10^6 sperm in 2-4 cc.

Front 40

sperm motility and lifespan in female tract

Back 40

increases dramatically in the female tract
lifespan is about 48 hrs

Front 41

sperm capacitation

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sperm must undergo and 4-6 hour process of capacitation within the female tract before they can fertilize an ovum

Front 42

capacitation involves

Back 42

changes in sperm surface characteristics by female-tract contituents
acrosome reaction

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acrosome reaction

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part of capacitation
acrosomal membrane and outer sperm membrane fuse, permitting release of hydrolytic and proteolytic enzymes which aid sperm penetration of the egg

Front 44

LH and spermatogenesis

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stimulates leydig cells to produce testosterone, which then acts on the seminiferous tubules
spermatogonia --> spermatocyte I

Front 45

FSH and spermatogenesis

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acts on seminiferous tubules directly
spermatocyte II --> spermatid --> spermatozoa

Front 46

other factors influencing spermatogeneis

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vitamin A
c-fos
stem cell factor
c-kit receptor for stem cell factor
cAMP-response element modulator (CREM)

Front 47

testicular regulation

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mostly T, some DHT
supports later stages of spermatogenesis

Front 48

T acts on sertoli cells to

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1. upregulate sertoli T receptors
2. upregulate sertoli ABP production
increase N-cadherin which increases spermatid binding to sertoli cells (enhancing spermatogenesis)

Front 49

inhibin

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produced by sertoli cells in males and granulosa cells in females
inhibits pit. FSH release
realease locally inhibited by androgen and estrogen

Front 50

activin

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acts primarily to stimulate pit. FSH release
locally blocks androgen and E synthesis
made by ovarian granulosa cells and has smiliar action in females and males

Front 51

importance of inhibin and activin

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provide a gonad-specific feedback loop for regulating gamete production

Front 52

effects of normal levels of prolactin

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upregulates androgen receptors in prostate and LH receptors in leydig cells

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excess levels of prolactin cause

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decreased FSH and LH
decreased androgen
decreased spermatogenesis and libido