Male reproductive Physiology

Question 1

What is the function of the testes

Answer 1

Production of male gametes and male sex hormone testosterone

Question 2

Where does spermatogenesis and spermatogenesis take place

Answer 2

Convoluted seminiferous tubules

Question 3

Where does testosterone production take place

Answer 3

In interstitial cells of Leydig , in between seminiferous tubule coils

Question 4

What glands create the fluid medium that transports the spermatozoa

Answer 4

1- Seminal vesicles
2- Prostate gland
3- Cow[ers Bulbourethral gland

Question 5

Where do the testes develop in fetus

Answer 5

In Abdomen and descends down inguinal canal and then lie at scrotum

Question 6

What is the condition in which the testes don’t descend and what can it lead to

Answer 6

Cryptorchidism can lead to infertility and increased risk of testicular cancer

Question 7

How is cryptorchidism corrected

Answer 7

Via surgery before birth , because testes can’t survive in the abdomen due to its temperature

Question 8

Why are the testes in an external location of body

Answer 8

Testes need to be 2-3 degrees below core temperature so spermatogenesis can occur.

Question 9

What alters the distance that the scrotal sac hangs from the abdomen depending if there is a need to conserve heat or ventilate

Answer 9

The cremaster muscle

Question 10

What helps remove heat from testes in countercurrent exchange mechanisms and how

Answer 10

Spermatic arteries and Pampiniform plexus of veins. Cool blood flowing out from the veins cools the blood in the spermatic arteries as the veins and arteries are parallel to each other

Question 11

What can reduce fertility in men

Answer 11

Hot baths and insulated athletic supporters

Question 12

What are the 4 stages of sperm formation

Answer 12

1- Spermatogenesis
2- Spermiogenesis
3- Spermiation
4- Capacitation (Spermatocytes become capable to fertilize ovum)

Question 13

Explain Spermatogenesis

Answer 13

Production of haploid gametes from diploid precursors

1- Spermatogonia become spermatozoa through dividing by mitosis
2- once divided , one cells matures to become spermatozoa and other forms permanent reserve
3- Daughter cell ( 2n + 2n ) then undergoes meiosis to develop 4 secondary spermatocytes ( haploids)
4- now called spermatids

Question 14

Explain Spermiogenesis & Spermaition

Answer 14

Gametes become motile

1- Sertoli cell nourished developing sperm cell , phagocytosis old cells and protects sperm from toxins
2- tight junctions between Sertoli cells forms a blood testicle barrier to stop substances from passing through
3- Spermiation : Sertoli cells secrete sperm into lumen along with with seminiferous tubule fluid

Question 15

What makes up the seminiferous tubule fluid

Answer 15

Fluid high in potassium , androgens , estrogen , inositol and glutamic acids

Question 16

Explain the structure of the Spermatozoon

Answer 16

1- Head : nuclear material + ayrosomal cap ( enzymatic )

2- Mid section : centrioles for cell division in fetus , mitochondria , micro tubular tail

Question 17

What is the purpose of the mitochondria in the midsection of the sperm

Answer 17

Necessary to provide energy for flagellum to rotate and make sperm motile

Question 18

What forms the micro tubular core of spermatozoon

Answer 18

Centrioles

Question 19

Where does capacitation occur

Answer 19

In epididymis and female genital tract

Question 20

Explain the Hormonal Control of Male reproductive tract

Answer 20

1- Daily release of GNRH ( usually at night )
2– Influences release of FSH and LH
3- FSH influences Sertoli cells to promote spermatogenesis & Sertoli secrete inhibit that acts as a negative feedback on FSH
3- LH acts on Leydig cells to release testosterone which negatively feedbacks to LH and GNRH

Question 21

What is the function of testosterone ( Hint: 6 )

Answer 21

1- Essential in spermiogenesis.
2- Gives male phenotype ( characteristics) in utero and prenatal structure changes that create male external genitalia
3- develops and maintains male reproductive system , responsible for changes at puberty
4- promotes adolescent growth spurt
5- anabolic hormone promoting muscle deposition and increased metabolic rate
6- behavioural effects on male libido and aggression

Question 22

Explain physiology of an erection

Answer 22

Dilation of penile arterioles fill erectile tissue of penis with blood. Corpus cavernosa and spongiosum then becomes turgor and more rigid in order to penetrate female.
Activation of parasympathetic dilator nerves and inactivation of sympathetic constrictor nerves

Question 23

What stimulates an erection

Answer 23

1- erotic cognitive stimuli and stimulation of sensory receptors on glans and anterior penis.
2- veins draining penis are compressed reinforced erection

Question 24

What drugs are used for erectile disfunction

Answer 24

Drugs increasing Nitric oxide production ( viagra ) and vasodilators (cGMP ) are used to treat erectile dysfunction

Question 25

Explain the phases of ejaculation ( Hint: 2 )

Answer 25

1- emission : sympathetic reflex stimulated nerves in smooth muscle of epididymis, vas deferens and accessory glands causes mix of sperm and secretion to mix to form semen that’s deposited in urethra
2- Expulsion : somatic reflex of skeletal muscles around base of penis ( bulbocavernosa ) expel semen with force out of the penis

Question 26

What is semen composed of

Answer 26

1- 60% of fluid from seminal vesicle : fructose for nourishment , prostaglandins and clotting agents
2- 25% from prostate glands containing citrate and protease to break down clotted semen
3- mucoid secretion of bulbourethral gland that lubricates the urethra and clears way before ejaculation

Question 27

What is PSA

Answer 27

Prostate specific antigen that is used as clinical marker for prostate cancer