Sexual reproduction In Humans

Question 1

What do Sertoli cells do?

Answer 1

Nourish the sperm
Protect spermatozoa from immune system

Question 2

What do leydig cells do?

Answer 2

Secrete testosterone

Question 3

Where does spermatogenisis occur?

Answer 3

Seminiferous tubule

Question 4

What is a polar body?

Answer 4

Uneven distribution of the cytoplasm

Question 5

What stage does meiosis stop at until puberty?

Answer 5

Prophase 1

Question 6

How is a secondary oocyte formed?

Answer 6

Once a month, puberty, primary oocyte resumes meiosis 1 and finishes it

Question 7

What is the follicle called that the secondary oocyte is contained in?

Answer 7

Graafian follicule

Question 8

When does the rest of meiosis occur for the secondary oocyte?

Answer 8

If fertilisation occurs

Question 9

What is the process called where the zygote undergoes repeated miotic divisions to form a blastocysts?

Answer 9

Cleavage

Question 10

Why is the process called cleavage?

Answer 10

Because the number of cells is increasing but no increase in size

Question 11

What is implantation?

Answer 11

Blastocyst moves into uterus where it attaches and sinks into endometrium

Question 12

What does the trophoblast divide into?

Answer 12

Chorion (chronic vili)
Amnion (amniotic sac and amniotic fluid)

Question 13

What does chronic vili do?

Answer 13

Secretes HCG
Large SA:V to absorb oxygen, aa, glucose

Question 14

What is the role of the amnion?

Answer 14

Shock absorber and keeps skin moist

Question 15

What does FSH do?

Answer 15

Stimulate follicule maturation, stimulates oestrogen production

Question 16

What does oestrogen do?

Answer 16

Stimulates LH, inhibits FSH, triggers repair of endometrium

Question 17

What does LH do?

Answer 17

Initiates ovulation, causes graafian follicule to develop into corpus luteum

Question 18

What does progesterone do?

Answer 18

Causes further development of endometrium
Inhibit FSH & LH

Question 19

Why does the cycle start again?

Answer 19

If no fertilisation, corpus luteum breaks down, no progesterone secreted
So… endometrium breaks down
Release of FSH, start cycle again

Question 20

In pregnancy, what secretes HCG?

Answer 20

Developing embryo

Question 21

What does HCG do? How long?

Answer 21

Maintains the corpus luteum for first 16 weeks

Question 22

What secretes which hormones after 16 weeks?

Answer 22

The placenta (oestrogen and progesterone)

Question 23

What does progesterone do during pregnancy?

Answer 23

Suppresses the uterus from contracting

Question 24

what does oestrogen do during pregnancy?

Answer 24

Stimulates growth of uterus to accommodate baby
Stimulate growth of mammary glands

Question 25

What is the role of oxytocin?
Example of?

Answer 25

Stimulate contraction of walls, this stimulates the production of more oxytocin
Positive feedback

Question 26

What is the role of prolactin?

Answer 26

Stimulates milk production

Question 27

What are the roles of the placenta?

Answer 27

Exchange of nutrients, barrier between maternal and foetal blood, protection from mothers immune system, protection from maternal and foetal blood pressure

Question 28

What is the role of the umbilical artery and umbilical vein during counter current flow?

Answer 28

Artery: deoxygenated blood from foetus to capillary bed
Vein: takes oxygenated blood back to foetus

Question 29

What is the role of the intervillous spaces ?

Answer 29

Filled with maternal blood, provides nutrients and oxygen to foetus