Reproduction, The Menstrual Cycle and Pregnancy

Question 1

What do each of the labels on the diagram refer to?

Answer 1

a) Vas deferens (sperm duct)
b) Urethra
c) Gland
d) Erectile tissue
e) Scrotum (scrotal sac)
f) Testis
g) Head of penis
h) Foreskin

Question 2

What role does testosterone play in the production of secondary sex characteristics?

Answer 2

• Extra hair on face and body.
• Development of muscles.
• Penis and testicles enlarge
• Production of sperm.
• Deepening of voice.

Question 3

What role does oestrogen play in the production of secondary sex characteristics?

Answer 3

• Extra hair on underarms and pubic area.
• Widening of hips.
• Development of breasts.
• Release of ovum (egg) and start of periods.

Question 4

What role does oestrogen play in the menstrual cycle?

Answer 4

• Causes the lining of the uterus to thicken and grow.
• Stimulates the release of an ovum at day 14.

Question 5

What role does progesterone play in the menstrual cycle?

Answer 5

Maintains the lining of the uterus.

• When the level of progesterone falls, the lining breaks down.

Question 6

What is the function of the testis?

Answer 6

Produce sperm cells.

Question 7

What is the function of the urethra (in males)?

Answer 7

Tube which carries sperm out during ejaculation, and urine passes out of the body through this tube as well.

Question 8

What is the function of the prostate?

Answer 8

To add fluid to the sperm to produce semen.

Question 9

What do each of the labels on the diagram represent?

Answer 9

a) Fallopian tube
b) Muscular uterus wall
c) Uterus
d) Ovary
e) Endometrium (uterus lining)
f) Cervix
g) Vagina

Question 10

What is the function of the Fallopian tube (oviduct)?

Answer 10

Muscular tube that carries the ovum to the uterus and is the site of fertilisation.

Question 11

What is the function of the uterus?

Answer 11

Organ where the embryo grows.

Question 12

What is the function of the ovaries?

Answer 12

• Release and develop eggs.
• Secrete oestrogen and progesterone.

Question 13

What is the function of the vagina?

Answer 13

Place where sperm are deposited of where an unfertilised egg will pass out.

Question 14

What role does the placenta play in the nutrition of a developing embryo?

Answer 14

• Blood vessels in the placenta enable the mother’s digested food molecules and oxygen to be absorbed by the placenta and used for the growth of an embryo.
• The proximity of the blood of the embryo and mother also allows waste to be exchanged to be excreted.

Question 15

How does the amniotic fluid protect a fetus?

Answer 15

The fluid (mainly water) cannot be compressed and therefore absorbs pressure so that the embryo is protected from knocks and bumps (forces on the uterus wall).

Question 16

What events happen at fertilisation and up to the production of the eight celled embryo?

Answer 16

1. Sperm (male gamete) and egg (male gamete) fuse.
2. A zygote forms.
3. The zygote undergoes mitosis (cell division).
4. The zygote divides three times.

Question 17

How is diffusion of nutrients made efficient in the placenta?

Answer 17

• There is a large concentration gradient.
• There is a large surface area.
• There is a short diffusion distance.

Question 18

What happens during each week of the menstrual cycle?

Answer 18

• First week:
  
  • menstruation happens
  • womb lining (endometrium) breaks down
• Second week:
  
  • a new egg matures in the ovaries
  • the womb lining is repaired
• Third week:
  
  • womb lining continues to grow

Question 19

When is the level of progesterone at its highest?

Answer 19

In the third week of the menstrual cycle, when the womb lining is growing.

Question 21

How many chromosomes are there in the nucleus of a sperm cell?

Answer 21

23 chromosomes - it is haploid.

Question 22

How many chromosomes are there in the nucleus of a egg cell?

Answer 22

23 chromosomes - it is haploid.

Question 23

How many chromosomes are in each cell in the embryo?

Answer 23

46 chromosome (or 23 pairs) - it is diploid.