Reproduction 1 (male anatomy)

Question 1

What are the male gonads?

Answer 1

Testes

Question 2

How many compartments do the testes have?

Answer 2

250-300

Question 3

What is the role of the seminiferous tubules?

Answer 3

Sperm production

Question 4

What is the role of the testes?

Answer 4

• Production of sperm (spermatogenesis)
• Delivery of sperm to female

They are the primary reproductive organ - the rest is secondary organs

Question 5

What are the 2 main cells of the testes?

Answer 5

• Leydig cells (interstitual cells)
• Sertoli cells (epithelial cells)

Question 6

What do the leydig cells do?

Answer 6

Secrete testosterone

They target the Sertoli cells

Question 7

What do the sertoli cells do?

Answer 7

Support sperm development (sperm maturation)

Question 8

Where are leydig & sertoli cells found?

Answer 8

Leydig cells are arranged in between the sertoli cells

The lumen is where the short sperm are release, this is why you get a sperm count in the millions

Question 9

What is the blood testis barrier like?

Answer 9

• Has tight junctions
• Luminal compartment
• Basal compartment

Question 10

Why is the blood-testis barrier important?

Answer 10

It is important as if the blood mixed w sperm then WBCs would kill the sperm

Question 11

What is the role of the smooth muscle in the testis?

Answer 11

Peristalsis to propel sperm

Question 12

What is the effect of testosterone before birth?

Answer 12

• Masculinses reproductive tracct & external genetalia
• Promotoes descent of testes into scrotum

Question 13

What effect does testosterone have on sex-specific tissues after birth?

Answer 13

• Promotes growth & maturation of the reproductive system at puberty
• Is essential for spermatogenesis
• Maintains the reproductive tract throughout adulthood

Question 14

How does testosterone effect other reproduction-related effects?

Answer 14

• Develops the sex drive at puberty
• Controls gonadotropin hormone secretion (testosterone)

Question 15

What effects does testosterone have on secondary sexual characteristics?

Answer 15

• Induces male pattern of HAIR growth (e.g. beard)
• Causes the VOICE to deepen bc of thickening of the vocal folds
• Promotes MUSCLE growth responsible for the male body configuration

Question 16

What effects does testosterone have on non-reproductive actions?

Answer 16

• Exerts a protein anabolic effect
• Promotes bone growht at puberty
• Closes the epiphyseal plates after being converted to estrogen by aromatose
• May induce aggression behaviour

Question 17

What are 3 functions of sertoli cells?

(Part 1)

Answer 17

• Support sperm devleopment
• Secrete luminal fluid in which sperm devleop
• Secrete androgen-binding protein

Question 18

What does androgen-binding protein do?

Answer 18

• Androgen buffer
• Helps maintain steady androgens in lumen

Question 19

What are 3 functions of sertoli cells?

(Part 2)

Answer 19

• Target cells to testosterone & FSH (secrete chemicals that stimulate spermatogenesis)
• Secrete inhibin
• Secrete MIS (embryonic only)

Question 20

What is inhibin?

Answer 20

Released from sertoli cells

Hormone of -ive feedback loop for FSH

Question 21

Summary slide of sertoli cells function:

List the 7 functions of Sertoli cells:

Answer 21

• Secrete fluid into lumen of seminiferous tubules to support sperm development & transport
• Provide nutrient for developing sperm
• Secrete paracrines that stimulate spermatogenesis
• Secrete inhibin
• Secrete Mullerian inhibiting substance in fetal life
• Form blood-testis barrier
• Secrete androgen-binding protein into lumen of seminiferous tubules

Question 22

What is the male copulatory organ?

Answer 22

Penis & scrotum

Question 23

What is the role of the penis & scrotum?

Answer 23

Penetrates vagina & deposits sperm

Question 24

At rest what is the penis like?

Answer 24

Flaccid

Question 25

What happens to the penis during sexual arousal?

Answer 25

Penis undergoes erection

Question 26

What are the 3 things that happens when a penis undergoes an erection?

Answer 26

- Blood flow to penis inc - Engorges erectile tissue - Penis swells & elongates

Question 27

What happens during ejaculation?

Answer 27

Sperm ejaculates thru urethra

Question 28

What are the characteristics of the scrotum?

Answer 28

- Suspended beneath penis - Houses testes - Sperm cannot develop at body temp

Question 29

How does the scrotum help with sperm being unable to develop at body temp?

Answer 29

- Thin walled sac - 2-3 degrees cooler - Dartos & cremaster muscles contract to regulate temp in cold (this is why in the cold testes shrink)

Question 30

Where is sperm stored?

Answer 30

In the epididymis

Question 31

What is the order of the sperm from the seminiferous tubules to the Vas deferens (short version)?

Answer 31

Seminiferous tubules --> Rete Testis --> Efferent ductules (exits testes) --> Epididymus --> Vas deferens

Question 32

What is the order of the movement of sperm form the seminiferous tubules to ejaculation (long version)?

Answer 32

- Starts in the testes in the SEMINIFEROUS TUBULE, exits this part - Into the RETE TESTIS where it is pulled into these EFFERENT DUCTULES - These connect to the EPIDIDYMUS where the sperm is stored until needed - when needed certain signals go here & transports the sperm to the VAS DEFERENS - Then in the VAS DEFERENS different structures are added - this is where semen is made, SEMINAL VESICLES are added & it makes its way to the; - EJACULATORY DUCT, from here it passes thru the PROSTATE GLAND as well where further chemicals are added - It then reaches the URETHRA where the final thing is added; which is secreted from the BULBURETHRAL GLANDS

Question 33

What is the order of the sperm from the Vas deferens to ejaculation (short version)?

Answer 33

Vas deferent --> (seminal vesicles added) --> Ejaculatory duct --> (prostate gland, chemicals are added) --> Urethra --> (Bulburethral glands) () = acessory glands adding things

Question 34

What are the acessory glands in the male reproductive system?

Answer 34

- Seminal vesicles - Prostate gland - Bulburethral glands

Question 35

What is the role of the seminal vesicles?

Answer 35

Secrete alkaline (important to neutralise pH in women) fluid w fructose, enzymes & prostoglandins

Question 36

What is the role of the prostate glands?

Answer 36

- Secrete citraze & enzymes - Helps sperm get thru ovum to the egg cell - Enzymes are used to break down the surface proteins on the surface of the egg cell so it can enter it

Question 37

What is the role of the Bulburethral glands?

Answer 37

Secrete viscous fliud w mucus

Question 38

What are prostoglandins important for?

Answer 38

To keep propelling the sperm to move

Question 39

What are the 2 types of male gonadotropins (hormones) & where are they released from?

Answer 39

- FSH - LH The hypothalamus that communicates w the anterior pituitary gland

Question 40

What is the role of FSH in men?

Answer 40

Stimulates gametogenesis

Question 41

What is the role of LH in men?

Answer 41

Stimulates androgen secretion (e.g. testosterone)

Question 42

Refer to the HPA axis on 2nd last slide

Answer 42

:)

Question 43

Describe the HPA axis for the production of LH:

Answer 43

- Hypothalamus releases gonadotropin releasing hormone (GnRH) - Targets the leydig cells - in response to LH the cells will secrete testosterone - This mainly targets the sertoli cells - Also released into the plasma --> has its own effects in tissues e.g. secondary sexual characteristics present themselves - Also a feedback loop here - the anterior pituitary gland & the hypothalamus, is therefore responsible for stopping release of GnRH & LH

Question 44

Describe the HPA axis for the production of FSH:

Answer 44

- Hypothalamus releases gonadotropin releasing hormone (GnRH) - FSH targets sertoli cells found in the testes, this drives spermatogenesis - Also drives secretion of another hormone inhibin --> part of -ive feedback to maintain stead amt of hormones in the blood to switch off the FSH signal

Question 45

What are blood levels of sex hormones like in males?

Answer 45

Fairly constant on short term basis Prepubescent: - Low blood levels Puberty & adulthood: - High blood levels

Question 46

What are the effects of androgens in males?

Answer 46

- Stimulate spermatogenesis - Promote development of secondary sex characteristics during puberty & maintenance of these characteristics in adult life - Inc sex drive - Promote protein synthesis in skeletal muscle - Stimulate growth hormone secretion, which permits bone growth during adolescence - Promote development of male reproductive structures during embryonic life