Male Reproduction

Front 1

where are sertoli cells found and what is their function

Back 1

found within the basal lamin of the seminiferous tubule

support maturation of spermatogonia

growth factors

androgen binding protein

beta-estradiol

have FSH receptors

Front 2

where are leydig cells and describe overall function

Back 2

found in the interstitium between seminiferous tubule

synthesize testosterone

have LH receptors

Front 3

what is the action of LH and which cell type does it affect?

Back 3

affects leydig cells

stimulates testosterone synthesis

Front 4

what is the molecule necessary for testosterone production at the first step and how can it be obtained

Back 4

cholesterol

synthesized de novo or... LH stimulates the synthesis of sterol carrier protein for the transport of cholesterol into the cell

Front 5

what enzyme is necessary for the conversion of cholesterol to the next molecule (what is it)?

Back 5

CYP11A1

pregnenolone

Front 6

testosterone can be converted to what molecule and which enzyme is necessary for its production?

Back 6

DHT

5 alpha-reductase

Front 7

what is the molecule that is immediately before testosterone is made?

Back 7

androstenedione

Front 8

what part of the cell is CYP11A1 found in?

Back 8

mitochondria

Front 9

what can testosterone be bound to when its not active?

Back 9

sex-hormone binding protein(SHBP_

albumin

corticosteroid-binding protein

Front 10

which molecule is more potent...testosterone or dihydrotestosterone (DHT)

Back 10

DHT

Front 11

testosterone is necessary for the differentiation of which male tissues?

Back 11

epididymis, vas deferens, seminal vesicles

Front 12

name some affects of testosterone on a growing male?

Back 12

increased muscle mass

pubertal growth spurt

closure of epiphyseal plates

growth of penis

deepening of voice

spermatogenesis

libido

Front 13

which is more important in negative feedback to the anterior pituitary---testosterone or DHT?

Back 13

testosterone

Front 14

DHT is necessary for the differentiation of which male tissues?

Back 14

penis, scrotum and prostate

Front 15

name the physical characteristics that DHT causes in a man

Back 15

male hair pattern

male pattern baldness

sebacous gland activity

growth of prostate

Front 16

describe the interactions between sertoli and leydig cells

Back 16

leydig cells
take up cholesterol and synthesize testosterone

testosterone diffuse across the BM and into the capillary network

some testosterone crosses the BM of the sertoli cells

testosterone is converted to estradiol through the action of aromatase- diffuses into circulation and some diffuses back into the leydig cells and governs their proliferation

testosterone in the sertoli cell also stimulates production of ABP - testosterone binds to ABP and taken into the lumen of the seminiferous tubule

Front 17

which cell type produces anti-mullerian hormone?

Back 17

sertoli cells

Front 18

describe the LH second messenger pathway in leydig cells

Back 18

LH has a receptor to which it binds on the leydig cell- GPCR

binding stimulates G protein and causes activation of adenyly cyclase

adenylyl cyclase acts leads to the production of cAMP - cAMP actiavtes PKA

PKA causes phosphyralation proteins that act as transcription factors

these factors cross the nuclear membrane and control produciton of certain proteins - such as CYP11A1 - part of rate limiting step of testosterone production

Front 19

describe the FSH second messenger pathway in the sertoli cells

Back 19

FSH binds to receptor

leads to activation of G protein

which leads to activaiton of adenylyl cyclase

increases cAMP

this causes the activation of PKA

PKA leads to production of transcription factors

these transcription factors govern the production of proteins such as ABP, aromatase, inhibins and growth factors

Front 20

discuss the actions that cause to the release of FSH and LH

Back 20

hypothalamus secretes GnRH

GnRH works at the level of the anterior pituitary and cases secretion of LH and SH

LH works on leydig cells

FSH works on sertoli cells

leydig cells produce testosterone

sertoli cells produce inhibins

Front 21

describe the negative feedback associated with male gonadal function

Back 21

the inhibins produced by sertoli cells inhibits the action of the anterior pituitary

the testosterone produced by leydig cells can inhibit hte action of the hypothalamus

testosterone can be converted to estradiol by aromatase and the estradiol can negatively affect the hypothalamus and anterior pituiatry

Front 22

describe how the male genitalia form embryologically instead of female

Back 22

sertoli cells secrete anti-mullerian hormone

which causes regression of mullerian tubes - no uterus

leydig cells secrete testosterone
which causes the continued growth of the wollfian duct

the wollfian duct differentiates into vas deferens, epididymus and seminal vesicles

testosterone is converted to DHT by 5alpha-reductase
causes the development of penis, penile urethra and scrotum

Front 23

decribe how the testosterone levels change as puberty is entered

Back 23

prior to puberty testosterone levels are low(except during fetal and neonatal stages where theyare high as well)

onset of puberty
-progressive and more frequent and greater amplitude of GnRH release
-up-regulation of GnRH receptors on pituitary gonadotrophs
-increased sensitivity of GnRH receptors

Front 24

follow the path of the sperm

Back 24

detach from lumen of seminiferous tubules

rete testis

efferent ductules

epidiymus: appx 50 days

ampulla of vas deferens

ejaculatory duct

prostatic urethra

penile urethra

Front 25

what is the acrosome?

Back 25

covering over the head of the sperm

Front 26

what are the three parts of the sperm

Back 26

head
midpiece
tail

Front 27

how would you classify the rate of spermatogenesis?

Back 27

constant
not accelerated by androgens or gonadotropins

Front 28

what is the daily sperm production for a 20 yearl old male vs a 50-90 year old male?

Back 28

20: 6.5 million sperm

50-90 3.8 million sperm

Front 29

how long does it take to transform a spermatogonia into a functional sperm?

Back 29

74 days

Front 30

name the four parts of the male sex act

Back 30

excitement

erection

emission

ejaculation

Front 31

what leads to excitement?

Back 31

tactile stimulation
- glans penis
-areas adjacent to male sex organs

psychologic stimuli

Front 32

sensory afferent are carried by what nerve

Back 32

pudental nerve

Front 33

what is the role of parasympathetics during the erection phase?

Back 33

acetylcholine release from parasympathetic fibers

casues release of NO

NO acts on vascular smooth muscle and causes dilation of penile arterioles

parasympathetic supply to the bulbourethral glands and urethral glands - leads to mucus production important in lubrication

Front 34

what is the emission phase of the male sex act

Back 34

movement of sperm into prostic and/or proximal urethra

Front 35

during the emission phase fluid is provided from what areas of the male anatomy

Back 35

fluid from seminal vesicles

fluid from prostate

fluid from cowper's glands

Front 36

describe the parasympathetic action during the emission phase

Back 36

helps determ amount and consistency of sperm

Front 37

describe the sympathetic action during the emission phase

Back 37

contractions of ampulla of the vas, seminal vesicles, and prostate

constricts the internal sphincter of the bladder

Front 38

what occurs during ejaculation

Back 38

forced expulsion of semen from the urethra

Front 39

how is the ejaculatory reflex triggered?

Back 39

movement of semen from the prostatic urethra into the bulbous urethra

Front 40

contraciton of what areas of the male anatomy are necessary for ejaculation

Back 40

perineal striated muscles

muscles surrounding corpus cavernosum and spongiosum