Lecture 69 - Male Reproductive Physiology

Question 1

What are the two main functions of the reproductive system?

Answer 1

1. Gametogenesis

2. Secretion of hormones

Question 2

What is gametogenesis?

Answer 2

Making gametes

Question 3

What are the two types of gametogenesis?

Answer 3

Oogenesis

Spermatogenesis

Question 4

Where does oogenesis occur?

Answer 4

Ovaries

Question 5

Where does spermatogenesis occur?

Answer 5

Seminiferous tubules

Question 6

Compare reproductive function in males and females

Answer 6

Females is much more complex
• reception of sperm
• fertilisation
• gestation
• parturition
• lactation

Question 7

What is parturition?

Answer 7

Delivery

Question 8

What is the name for sperm cells at the end of mitosis?

Answer 8

Spermocytes

Question 9

How many chromosomes in the gametes?

Answer 9

23

Question 10

When does spermatogenesis begin?

How about oogenesis?

Answer 10

Males: puberty
Females: foetal life

Question 11

Where are germ cells?

Answer 11

Embryonic gonad

Question 12

How are gametes produced?

Answer 12

Meiosis from embryonic gonad

Question 13

Describe the stages of spermatogenesis

Answer 13

Spermatogonium
- Mitosis -
Spermatogonia
- Mitosis -
Primary spermatocyte
- 1st meiotic division -
Secondary spermatocyte
- 2nd meiotic division -
Spermatids
- maturation -
Spematozoa

Question 14

Where are spermatigonia?

Answer 14

Edge of seminiferous tubule

Question 15

Which hormone drives spermatogenesis?

Answer 15

Testosterone

Question 16

What do we have after the first meiotic division in oogenesis?

Answer 16

Secondary oocyte + polar body

Question 17

Describe the process of oogensis

Answer 17

Oogonium
- Mitosis -
Primary oocyte
- 1st meiotic division -
Secondary oocyte + polar body
- 2nd meiotic division -
Mature ovum

Question 18

When does mitotic proliferation occur in oogenesis?

What is the implication of this?

Answer 18

Completely during foetal life

Menopause: no more primary oocytes

Question 19

What does each primary oocyte give rise to?

Answer 19

One mature ovum

3 polar bodies

Question 20

What is the function of the polar body?

What happens to it?

Answer 20

Non functional

Degenerates

Question 21

What does the second meiotic division in oogenesis give rise to?

Answer 21

Mature ovum + second polar body

Question 22

When is oogenesis completed?

Answer 22

After fertilisation

Sperm is required

Question 23

What is sperm required for in oogenesis?

Answer 23

Second meiotic division

Question 24

When does the second meiotic division occur?

Answer 24

Fertilisation

Question 25

Which cells produce testosterone?

Answer 25

Leydig cells

Question 26

Where are the Leydig cells?

Answer 26

Interstitial space

Question 27

Where are oestrogen and progesterone produced?

Answer 27

Follicular cells | Corpus luteum

Question 28

What are the sex steroids?

Answer 28

Testosterone Oestrogen Progesterone

Question 29

How is sex steroid production regulated?

Answer 29

1. Hypothalamus - releases GnRH 2. Anterior pituitary - LH - FSH 3. Gonads - steroid and peptide hormones Long feedback loops - Steroid and peptide hormones - acting on Hypothalamus and/or pituitary - may be positive or negative feedback - higher cortical centres

Question 30

What is GnRH?

Answer 30

Gonadotrophin releasing hormone

Question 31

What are the peptide hormones? What do they do?

Answer 31

Inhibin Activin Help regulation

Question 32

What are all sex steroids synthesised from?

Answer 32

Cholesterol

Question 33

From what is oestrogen synthesised?

Answer 33

Testosterone

Question 34

What is estrdiol?

Answer 34

The main oestrogen

Question 35

What are LH and FSH? | Describe their function

Answer 35

Luteinising hormone Follicle stimulating hormone Circulate in blood to gonads to: • produce gametes • secretion of sex hormones

Question 36

What are the target cells of LH and FSH in males and females?

Answer 36

LH: Females: Theca cells Males: Leydig cells FSH: Males: Sertoli cells Females: Granulosa

Question 37

What is LH's main function?

Answer 37

Hormone secretion from endocrine cells

Question 38

What is FSH's main function?

Answer 38

``` Gamete production Males: • Sertoli cells Females: • Granulosa ```

Question 39

Describe how higher cortical centres can affect hormone release

Answer 39

eg. Stress in females can alter release of hormones so that menstruation does not occur

Question 40

In males is the primary target for FSH in males? | What does this bring about?

Answer 40

Sertoli cells | Spermatogenesis

Question 41

What does LH do in males? | What are the downstream effects?

Answer 41

Testosterone production 1. Released from anterior pituitary 2. Acts on Leydig cells 3. Release of testosterone 4. Testosterone acts on Sertoli cells 5. Spermatogenesis etc.

Question 42

Where does maturation of sperm occur?

Answer 42

Head of epididymis

Question 43

Draw a cross section of a seminiferous tubule, indicating all the different cell types

Answer 43

Spermatogonia and all derivatives Sertoli cells Leydig cells

Question 44

What is the function of testosterone?

Answer 44

``` Before brith: - gonad --> testis Development: • of reproductive system • spermatogenesis • sex drive Secondary sex characteristics • hair growth • voice deepening • muscle growth ``` NB also non-reproductive actions • anabolism, bone growth

Question 45

Describe feedback in males

Answer 45

Negative feedback • testosterone • FSH

Question 46

What is the role of the accessory glands?

Answer 46

Contribute to the volume of semen

Question 47

Describe the function of inhibin

Answer 47

Released from seminiferous tubules Negative feedback on anterior pituitary Stops release of FSH

Question 48

Describe the feedback of testosterone

Answer 48

Negative feedback • hypothalamus • anterior pituitary

Question 49

What is Andropause?

Answer 49

Decreased levels of testosterone through aging

Question 50

Describe the function of the Leydig cells, and how this is controlled

Answer 50

1. Acted on by LH | 2. Produce and release testosterone