Lect 26

Question 1

What hormone secretion is very low during prepubertal phase? Why?

Answer 1

• LH and FSH low
• due to active neural inhibition of GnRH release

Question 2

What hormones are secreted during puberty

Answer 2

• increased secretion of GnRH -> LH and FSH
  
  • stimulation in spermatogenesis and testosterone production

Question 3

What happens to testosterone during senescence

Answer 3

• senescence: the condition or process of deterioration with age.
  
  • decrease in production of sperm and testosterone

Question 4

What are the signs of androgen deficiency in aging males (ADAM)

Answer 4

• decrease in
  
  • bone formation
  • muscle mass
  • libido
  • hematocrit
• increase in
  
  • facial hair
• changes in appetite

Question 5

What glands/organs are responsible for ejaculate (semen) production

Answer 5

• accessory glands (90%)
  
  • Seminal vesicles: 60%
  • prostate: 20%
  • Bulbourethral gland: 10%
• sperm compose remaining 10%

Question 6

Where are the seminal vesicles

Answer 6

• there are two
• empty into last portion of the ductus deferens, one on each side

Question 7

Where are the Bulbourethral gland

Answer 7

• pair
• empty into urethra, just before urethra enters penis

Question 8

function of prostate gland

Answer 8

• secretes alkaline fluid that neutralizes the acidic vaginal secretions

Question 9

take home point: what is the function of seminal fluid

Answer 9

• help support and maintain sperm function in the female reproductive tract

Question 10

prostate disease are common at what age

Answer 10

after age 50

Question 11

what is benign prostatic hyperplasia

Answer 11

• enlarged prostate, which may cause dribbling after urination or a need to go often, especially at night

Question 12

cause of male erection

Answer 12

• arterioles in penis dilate
  
  • penis engorges with blood

Question 13

penile erectile tissue is composed on three erectile tissues. name them

Answer 13

• 2 corpora cavernosa
• 1 corpus spongiosum

Question 14

explain the erection reflex in males

Answer 14

• basic spinal reflex
• mechanoreceptors stimulated in glans penis
  
  • parasympathetic innervation of arterioles in penis
• can be facilitated or inhibition by higher brain centers

Question 15

Explain the erect state (tumescence) of erectile response

Answer 15

• relaxation of helicine arteries by NO
  
  • blood flows into cavernous spaces -> engorgement and erection

Question 16

Explain the flaccid state of erectile response

Answer 16

• blood flow into cavernous space is limited by contraction of helicine arteries

Question 17

ejaculation is stimulated by what

Answer 17

SNS

Question 18

ejaculation is composed of what two phases

Answer 18

1. Emission (SNS impulses from L1 and L2)
   
   • semen enters urethra
   • SNS stimulation of smooth muscle and contraction of accessory glands
2. Expulsion
   
   • filling of urethra triggers SNS which activated skeletal muscles at base of penis

Question 19

list the ejaculation pathway

Answer 19

• vas deferens -> ampulla -> urethra -> outside

Question 20

what contracts to prevent retrograde ejaculation into bladder

Answer 20

internal urethral muscle

Question 21

Male sexual response: Psychic stimuli causes activation in brain at what centers

Answer 21

• cortex
• limbic
• hypothalamus

Question 22

Male sexual response: PNS arterial dilation via NO and Ach causes what 3 things

Answer 22

• vasocongestion
• engorgement of genitalia
• stimulation of bulbourethral glands

Question 23

Male sexual response: SNS impulses lead to

Answer 23

• emission and expulsion of sperm
• contraction of pelvic musculature to enhance sperm motility

Question 24

Most common tx options for erectile dysfunction

Answer 24

• phosphodiesterase inhibitors (PDE5)
  
  • enhance effect on NO on penis in smooth muscle
  • Sildenafil (viagra)
  • Tadalafil (Cialis)
  • Vardenafil (Levitra)

Question 25

MOA of phosphodiesterase inhibitors (PDE5)

Answer 25

prevent cGMP degradation so that cGMP can activate myosin phosphatase in smooth muscle -> promotes relaxation

Question 26

Mechanism of Vasectomy

Answer 26

• surgical cut of each vas deferens
• prevents sperm migration along ejaculatory track
• sperm are discharged by phagocytosis
• *does not interfere with testosterone activity

Question 27

can vasectomy be reversed

Answer 27

yes, with 70% effectiveness -> vasovasostomy

Question 28

MOA of the male contraception: Desotrogestrel and Etonogestrel

Answer 28

• synthethic progestin given in combo with testosterone IM
• produces severe oligoazoospermia
• not currently available on local market

Question 29

side effects of Desotrogestrel and Etonogestrel

Answer 29

• acne
• increased body weight
• decreased HDL

Question 30

MOA of IVD: intra vas device

Answer 30

• new male contraceptive
• inserted into scrotum and blocks vas deferens
• in pilot studies