Male Reproduction

Question 1

What do the testes (male gonads) do?

Answer 1

produce sperm (by spermatogenesis) and sex steroid hormone testosterone

Question 2

What is the reproductive tract?

Answer 2

system of ducts specialized to store and/or transport sperm

Question 3

What are the 3 parts of the reproductive tract?

Answer 3

• epididymis
• vas deferens
• urethra

Question 4

What does the vas deferens do?

Answer 4

connects testes with structures within pelvic cavity – travels along urinary bladder to the back

Question 5

What do accessory sex glands do?

Answer 5

produce supportive secretions

Question 6

What are the 3 accessory sex glands?

Answer 6

seminal vesicles
prostate
bulbourethral (Cowper’s) glands

Question 7

What is the penis?

Answer 7

copulatory organ

Question 8

What does the penis contain?

Answer 8

• spongy (penile) urethra

- erectile tissues – one corpus spongiosum, two corpora cavernosa

Question 9

What is the spongy (penile) urethra?

Answer 9

part of urethra within penis

Question 10

What does the corpora cavernosa contain?

Answer 10

blood vessels (erection)

Question 11

Spermatogenesis

What does spermatogenesis require?

Answer 11

relatively low temperature

optimal temperature for sperm production is 34-36 ºC

Question 12

Spermatogenesis

What are the specific adaptations that result in lowering temperature of testes? (4)

Answer 12

• superficial location of testes in scrotum
• dartos muscle
• cremaster muscle
• pampiniform plexus

Question 13

What is the dartos muscle?

Answer 13

smooth muscle found just directly under skin that forms small wrinkles that can cause surface area to change slightly

Question 14

What is the cremaster muscle?

Answer 14

skeletal muscle that contracts to bring testes closer to body cavity (occurs when temperature of external environment is low)

Question 15

What is the pampiniform plexus?

Answer 15

network of veins and single artery

Question 16

Spermatogenesis

Where do testes go during fetal development?

Answer 16

descend from inside body cavity adjacent to kidneys to scrotum

Question 17

Spermatogenesis

During embryonic life, what develops high on the posterior abdominal wall?

Answer 17

testes, their ducts (epididymis and vas deferens), blood vessels, and nerves

Question 18

What does retroperitoneal mean?

Answer 18

area outside or behind the peritoneum (the tissue that lines the abdominal wall and covers most of the organs in the abdomen)

Question 19

What does intraperitoneal mean?

Answer 19

within or administered through the peritoneum

Question 20

Spermatogenesis

By the 3rd month, where are testes?

Answer 20

descend to pelvis

Question 21

Spermatogenesis

By time of birth, where are testes?

Answer 21

enter scrotum

Question 22

Spermatogenesis

What happens if testes stayed in body cavity?

Answer 22

spermatogenesis cannot occur (too warm)

Question 23

Spermatogenesis

What does each testis consist of?

Answer 23

series of ducts including about 800 sperm-producing seminiferous tubules

Question 24

Spermatogenesis

What are Sertoli cells?

Answer 24

cells that line walls of seminiferous tubules – essential for proper sperm development

Question 25

Spermatogenesis

What are Leydig cells? What do they do?

Answer 25

cells located between seminiferous tubules that secrete sex steroid hormone testosterone

Question 26

Spermatogenesis

What do seminiferous tubules eventually combine to form?

Answer 26

epididymis, which then forms vas deferens

Question 27

Where does spermatogenesis take place?

Answer 27

within seminiferous tubules

Question 28

Spermatogenesis

How do germ cells develop?

Answer 28

in close relationships to sertoli cells

Question 29

Spermatogenesis

How long do men produce sperm?

Answer 29

throughout their adult lives (from puberty until death)

Question 30

Spermatogenesis

What is mitosis?

Answer 30

biological process that allows spermatogenesis to continue uninterrupted for decades

Question 31

Spermatogenesis Stages

Answer 31

1. spermatogonium (23 chromosomes)
2. primary spermatocyte (23 chromosomes)
3. secondary spermatocyte (23 chromosomes)
4. spermatids (46 chromosomes)
5. spermatozoon (46 chromosomes)

Question 32

Spermatogenesis Process

Answer 32

1. spermatogonium undergoes mitotic proliferation into primary spermatocyte – one daughter cells enters spermatogenesis, and one daughter cells becomes next generation
2. primary spermatocyte undergoes meiosis I → becomes secondary spermatocyte
3. secondary spermatocyte undergoes meiosis II → becomes spermatids
4. spermatids undergo spermatogenesis (maturation of sperm) → becomes spermatozoon

Question 33

Where do sperm go following spermatogenesis?

Answer 33

enter epididymis and vas deferens where they undergo maturation and storage, respectively

Question 34

Spermatogenesis

What is endocrine activity of testis regulated by?

Answer 34

hypothalamic-pituitary-testis axis

Question 35

Endocrine Activity of Testis is Regulated by Hypothalamic-pituitary-testis Axis

Steps

Answer 35

1. hypothalamic GnRH induces LH and FSH release from anterior pituitary
2. LH controls testosterone production (binds to Leydig cells), and FSH controls spermatogenesis (binds to Sertoli cells)
3. testosterone provides negative feedback effect on production of GnRH, LH, and FSH
   - testosterone has negative feedback on hypothalamus and anterior pituitary
   - release of hormones is always controlled by negative feedback
4. inhibin produced by Sertoli cells provides negative feedback effect on production of FSH only (inhibits release of FSH)