McCumbee - Male Repro

Question 1

Spermatogenesis begins __

Answer 1

At puberty

Question 2

The majority of estradiol in males is made in _____ from testosterone

Answer 2

Adipose tissue

Question 3

What constitutes bioavailable testosterone

Answer 3

Free testosterone and testosterone bound to albumin

Albumin testosterone easily dissociates

Question 4

5alpha-reductase inhibitors are useful in treating?

Answer 4

Benign prostatic hyperplasia

Prostate cancer

Question 5

Where can the conversion of testosterone to estradiol (via the aromatase enzyme) occur (x3)

Answer 5

certain CNS nuclei

Adipose tissue

Leydig and Sertoli cells

Question 6

___ promotes androgen biosynthesis in Leydig Cells

Answer 6

LH

Question 7

What does the age-related increase in Sex hormone binding globulin do ?

Answer 7

Causes there to be less bioavailable testosterone

Question 8

Androgens promote protein _______

Answer 8

Anabolism

Question 9

What do androgens do at puberty?

Answer 9

Promote the maturation of reproductive structures

Promote the development of secondary sex characteristics

Question 10

Androgens ______ erythropoietin synthesis

Answer 10

Stimulate

Question 11

Function of sertoli cells

Answer 11

Transfer nutrients to the developing germ cells

Create an environment that is conducive for germ cell differentiation into mature spermatozoa

Question 12

The sertoli cells secrete ? (X3)

Answer 12

Estradiol (E2)

Glycoproteins of the TGFbeta family (AMH, activin, inhibins)

Androgen binding protein (ABP)

Question 13

Both FSH and testosterone ______ ABP production by sertoli cells

Answer 13

Stimulate

Question 14

Clinically, how is sertoli cell function assessed?

Answer 14

By measuring ABP production.

Question 15

What is the primary function of Inhibin B (secreted from Sertoli cells)

Answer 15

Exerts a negative feedback effect on GnRH stimulated FSH secretion

Question 16

E2 (estradiol) is formed by the aromatization of testosterone in response to ______ stimulation

Answer 16

FSH

Question 17

What is the role of FSH on sperm production?

Answer 17

FSH is required for maintenance of normal levels of sperm production

Acts on Sertoli cells

Need the regular pulsatile delivery of GnRH to the gonadotropes

Question 18

How are the actions of FSH on Sertoli cells mediated?

Answer 18

Thru a GPCR which activates the cAMP singaling pathway.

Question 19

What are the ways that FSH acts on Sertoli Cells?

X5

Answer 19

Promotes proliferation of sertoli cells in the immature testes

Maintains normal Sertoli cell function in mature testes

Works thru sertoli cells to produce growth factor and anti-apoptotic factor for spermatogonia

Increase production of androgen binding protein to keep high androgen levels in lumen of seminiferous tubules

Stimulates inhibin synthesis

Question 20

How does LH promote spermatogenesis?

Answer 20

Indirectly, by stimulating the Leydig cells to produce testosterone

Question 21

What happens to spermatazoa in the epididymis?

Answer 21

They spend about a month here for maturation. They develop unidirectional motility and are coated with a substance that protects from decapacitance.

Epididymis is also a sight of sperm storage.

Question 22

The first detectable change in gonadotropin production in the late prepubertal period is _____

Answer 22

A sleep associated surge in LH release

Question 23

Testosterone ______ the hypothalamic pulse generator

Answer 23

Inhibits

Question 24

Inhibin is secreted by ?

Answer 24

Sertoli cells

Question 25

FSH and Testosterone _________ the production of inhibin

Answer 25

Increase

Question 26

Inhibin _______ FSH release

Answer 26

Inhibits

Question 27

In the flaccid state, the blood flow is minimal because these vessels are constricted

Answer 27

Helicine arteries

Question 28

During sexual stimulation, in males, mucus is secreted by _______ and _______ glands

Answer 28

Urethral Bulbourethral

Question 29

The movement of semen into the proximal part of the urethra Involves coordinated rhythmic contractions of smooth muscle in vas deferens, ampulla, prostate and seminal vesicles

Answer 29

Emission

Question 30

Testosterone _-___ the hypothalamic pulse generator

Answer 30

Inhibits

Question 31

Efferent parasympathetic fibers to the sinusoidal spaces and helicine arteries release ______ and _____ to elicit the erectile response

Answer 31

Nitric Oxide Vasoactive intestinal peptide (VIP) Both are vasodilatory, relaxing arteries and sinusoids

Question 32

The erectile response is mediated at the ______ section of the spinal cord The emission response is elicited at the _________ section of the spinal cord

Answer 32

Sacral Lumbar

Question 33

Emission is mediated by sympathetic neurons in the upper lumbar region releasing norepinephrine for ______ receptors

Answer 33

Alpha-1

Question 34

What is seen in classic Klinefelter Syndrome?

Answer 34

Extra X’s Most common XXY Seminiferous tubules are fibrotic and hyalinized. Germ cells not typically present in testes Typically infertile Function of leydig cells variable. Hypogonadism (testes small and firm) Androgen deficiency, estrogen excess Gynecomastia and lack of pubic hair common

Question 35

What labs are commonly seen in Klinefelter syndrome? 4

Answer 35

FSH and LH elevated Testosterone levels are low to normal Estradiol levels elevated

Question 36

What happens in orchitis:

Answer 36

Inflammation of testes leads to destruction of the seminiferous tubules. Can be secondary to mumps Leydig cells not usually affected (Orchitis is a type of primary hypogonadism)

Question 37

In Kallmann’s syndrome, circulating levels of gonadotropins are ____

Answer 37

Low

Question 38

Explain Kallmann’s syndrome

Answer 38

Secondary hypogonadism Isolated gonadotropin deficiency due to deficient production of GnRH in the hypothalamus Arrested spermatogenesis in testes Low circulating gonadotropes Decreased sense of smell Sympt’s of androgen deficiency at puberty