Male Physiology

Question 1

Where do the testis develop?

Answer 1

abdominal cavity of the foetus

Question 2

What causes the testis to drop into the scrotal sac before birth?

Answer 2

androgen dependant

Question 3

By what age should the testes have decended naturally?

Answer 3

6 months

Question 4

Why do the testes need to descend?

Answer 4

lower temp outside the body allows spermatogenesis to occur

nervous reflexes cause muscle contractions to lower or raise the testes according to external temperature

Question 5

What is Cryptorchidism?

Answer 5

failure of the testes to descend by the time the individual reaches adulthood

Question 6

What are the implications of cryptorchidism?

Answer 6

reduces the sperm count

if it is unilateral they can still be fertile

Question 7

What is the treatment of cryptorchidism?

Answer 7

orchidplexy by 12 months to reduce infertility risk

should be performed by 12 years to reduce testicular cancer risk (x6)

Question 8

What is the role of the sertoli cells?

Answer 8

spermatogenesis from the seminiferous tubules
form a blood-testes barrier - protects sperm against antibody attack
secretes androgen binding globulin - binds testosterone so conc stays high
secretes inhibit and activin hormones - regulate FSH secretion and controle spermatogenesis

Question 9

What is the role of the leydig cells?

Answer 9

produce testosterone

Question 10

What covers the head of the sperm?

Answer 10

acrosome - contains enzymes for penetrating the ovum

Question 11

What is contained in the head, midpeice and tail of the sperm?

Answer 11

head - nucleus
midpiece - mitochondria to power the tail
tail - microtubules

Question 12

What are the characteristics of GnRH?

Answer 12

released every 2-3 hours
starts being released aged 8-12
under negative feedback from testosterone

Question 13

What is the role of LH?

Answer 13

acts on Leydig cells and regulates testosterone
release stimulated by GnRH
release inhibited by testosterone

Question 14

What is the role of FSH?

Answer 14

acts on sertoli cells and enhances spermatogenesis
release stimulated by GnRH
release inhibited by testosterone

Question 15

What are the effects of testosterone on the body before brith?

Answer 15

masculinises the reproductive tract and promotes the descent of the testes

Question 16

What are the effects of testosterone on the body during puberty?

Answer 16

promotes puberty and male characteristics - growth and maturation of the male reproductive system

Question 17

What are the effects of testosterone on the bod in adult life?

Answer 17

controls spermatogenesis, secondary sexual characteristics, libido, penile erection and aggressive behaviour

Question 18

Where is testosterone produced?

Answer 18

leydig cells

Question 19

What is the role of inhibin?

Answer 19

inhibit FSH

Question 20

What is the role of activin?

Answer 20

stimulates FSH

Question 21

After ejaculation, how is spermatoza liquified?

Answer 21

prostate gland

Question 22

What is the function of the epididymis and vas deferens?

Answer 22

exit route from the testis -> urethra
concentrate and store sperm
site for sperm maturation

Question 23

What is the function of the seminal vesicles?

Answer 23

produce semen into the ejaculatory duct, supply fructose, secrete prostaglandins (cause contractility), secrete fibrogen (clot precursor)

Question 24

What is the function of the prostate gland?

Answer 24

produces an alkaline fluid to neutralise the acidic vagina

produces clotting enzymes to clot the semen inside the vagina

Question 25

What is the function of the bulbourethral glands?

Answer 25

secrete mucus to act as a lubricant

Question 26

Where does the blood fill up during an erection?

Answer 26

corpus cavernousa