Fertility & Early Development

Question 1

What must sperm do in the tract before fertilising the ovum?

Answer 1

Capacitate

Question 2

What happens during capacitation (sperm maturation)?

Answer 2

Sperm swims through mucous and it scrapes off some molecules so that its ready for capacitation –> fertilisation

Question 3

In IVF what must be done before fertilisation?

Answer 3

Artificial capacitate the sperm

Question 4

Motility changes of sperm

Answer 4

1. Hyper motile to get to egg

2. Slows down and swims in a star shape to hit egg

Question 5

When are eggs held in meiosis 1?

Answer 5

When the child is unborn in her mother’s uterus

Question 6

When does an egg enter meiosis 2?

Answer 6

When ovulated

Question 7

When do eggs complete meiosis?

Answer 7

When fertilised

Question 8

When does random selection occur?

Answer 8

• Half chromosomes from each parent
• Randomly selects which paternal chromosomes enter gametes
• Crossing over gametogenesis

Question 9

What did Jost show?

Answer 9

Sexual phenotype depends on gonads

Question 10

What is the testis determining gene?

Answer 10

SRY

Question 11

Where is the SRY gene found?

Answer 11

On the Y chromosome

Question 12

What are required for ovary development?

Answer 12

Oocytes

Question 13

Can testes form in the absence of sperm?

Answer 13

Yes

Question 14

Where do gonads develop?

Answer 14

In gonadal ridges

Question 15

What are gonadal ridges precursors for?

Answer 15

Mesenephros (primitive kidneys) and internal tubes and ducts

Question 16

What is the allantois?

Answer 16

Collects liquid waste from embryo and gas exchange

Question 17

What are the primitive germ cell in gonad development called?

Answer 17

Primordial germ cells

Question 18

Reaction of oogonia to oocytes

Answer 18

Oogonia (mitotic) ————-> oocytes (meiotic)

requires meiosis inducing substance (MIS)

Question 19

What does a decline in oogonia mean in terms of FSH levels?

Answer 19

Decrease in FSH

Question 20

What is required for oogonia —> oocytes?

Answer 20

Meiosis-inducing substance

Question 21

Males also produces MIS from mesonephric ducts but how is it that testes are formed?

Answer 21

The testis cords produce meiosis preventing substance (MPS)

Question 22

What happens to the testis cords at puberty?

Answer 22

The testis cords transform to seminiferous tubules which produce sperm throughout life after puberty