YEAR 1 - GONADS

Question 1

What are the functions of the gonads?

Answer 1

1. Gametogenesis
2. Steroidogenesis

Question 2

What is gametogenesis?

Answer 2

Production of gametes - spermatogenesis in males and oogenesis in females

Question 3

What is Steroidogenesis?

Answer 3

Production of steroid hormones - androgens in males and oestrogen and progesterone in females

Question 4

What is the activation of germ cells like in males?

Answer 4

• Germ cells proliferate reaching numbers of around 6-7 million during embryogenesis
• They remain high throughout life but have a dormant period until puberty

Question 5

What is the activation of germ cells like in females?

Answer 5

During embryogenesis the germ cells proliferate reaching numbers around 6-7 million

Question 6

Draw a graph showing the levels of germ cells in males and females throughout lifespan

Answer 6

Question 7

Describe the process of spermatogenesis

Answer 7

• Germ cells start to multiply and differentiate into spermatogonia (DIPLOID)
• during puberty - FSH begins to be released -> supermatogonia divide by mitosis to produce either more spermatogonia or primary spermatocytes (DIPLOID)
• primary -> secondary is first meiotic division (HAPLOID)
• secondary to spermatids is second meiotic division
  *

Question 8

Describe the process of oogenesis

Answer 8

• As soon as the oogonia get to the first meiotic division (prophase), development is halted
• the oocytes form a layer of cells around them to create the primordial follicles (happens at pre-birth)
• oocytes lie dormant for 12-50 years
• during puberty - some oocytes rescued by FSH release and some begin atresia
• at ovulation , oocytes complete first meiotic division to create a secondary oocyte and a polar body
• secondary oocyte enters 2nd division which completes upon fertilisation -> ovum and second polar body

Question 9

What are the principal structures in the testes

Answer 9

Question 10

Where does spermatogenesis take place?

Answer 10

Seminiferous tubules

Question 11

Where is spermatozoa collected and stored

Answer 11

collection in the rete testis, and then drained by the vasa efferentia into the epididymis to be stored

Question 12

Label the seminiferous tubules

Answer 12

Question 13

What are the functions of Sertoli cells?

Answer 13

• Provide structural and metabolic support for spermatogenesis
• forms seminiferous tubukles
• synthesize FSH and androgen receptors
• Produces INHIBIN in response to FSH, which inhbits FSH secretion|

Question 14

What are the functions of the Leydig cells?

Answer 14

Synthesises LH receptors

Question 15

What are Graffian follicles?

Question 16

Where are all follicles embedded?

Question 17

What does the Graffian follicle become after ovulation?

Question 18

Label the ovaries

Answer 18

Question 19

Using simple flow charts, illustrate the synthesis of progesterone, 17B-oestradiol, and testosterone

Answer 19

Question 20

What do oestrogens do?

Question 21

Summarise the principal ovarian and endometrial changes that occur during the menstural cycle

Answer 21

• Oestrogen causes the effects of the proliferative phase
  
  • ie: stimulates mitosis and an increase in progesterone and oestrogen receptors
• Endometrium gets thicker, glands get bigger and blood vessels lengthen
• in the luteal phase, oestrogen and progesterone are produced which induces a secretory phase
• progesterone reverses the effect of oestrogen
  
  • reduced proliferation by reducing oestrogen receptors
    
    • increases secretory activity of cells of myometrium - glands become wider and produce substances that make the environment suitable for implantation to occur

Question 22

Explain the hormone level changes during the menstrual cycle

Answer 22

Question 23

Draw a graph of the hormone changes during menstruation

Answer 23

Question 24

What are the ovarian changes that occur during the menstrual cycle?

Answer 24

Question 25

Which cells are LH receptors in the follice

Question 26

Which cells are FSH receptors in the follicle?

Question 27

What do thecal cells do?

Question 28

What do granulosa cells do?