Reproduction in humans

Question 1

Testis

Answer 1

• Produces sperms
• Produces male sex hormones, testosterone

Question 2

Sperm duct

Answer 2

• Pathway travelled by sperm after they are released from the testis to the urethra

Question 3

Urethra

Answer 3

• Urine and semen exit the body through this tube

Question 4

Scrotum

Answer 4

• Maintains a lower temperature for the development of sperms outside the body

Question 5

Penis

Answer 5

• Becomes erect and hard during sexual intercourse to enter and deposit semen in the vagina of female

Question 6

Prostate gland

Answer 6

• Activates sperms by secreting a fluid that contains nutrients and enzymes

Question 7

Ovary

Answer 7

• Produces egg
• Produces female sex hormone, progesterone and oestrogen

Question 8

Oviduct

Answer 8

• Fertilization occur here
• Mature egg is released from the ovary into the oviduct

Question 9

Uterus

Answer 9

• Location where the fetus develops
• Has elastic muscular wall that enables contraction during birth to expel the fetus

Question 10

Cervix

Answer 10

• It is the circular ring of muscle and the lower end of the uterus
• It dilates during birth to allow the fetus to pass

Question 11

Vagina

Answer 11

• Location where semen is deposited during sexual intercourse

Question 12

Structure of sperm

Answer 12

1. Contains a flagellum
   - enables the sperm to swim towards the egg
2. Contains many mitochondria
   - To provide more energy for the sperm to swim towards the egg

Question 13

Menstrual cycle

Answer 13

Day 1 - 5:
- Menstruation
- Uterine lining breaks down
- Uterine lining, blood and unfertilized egg is discharged out of the body through the vagina

Day 6 - 10:
- Repair of uterine lining
- Ovary produces oestrogen to stimulate the uterine lining to repair and grow

Day 11 - 16:
- Fertile period
- Sexual intercourse during fertile period is likely to result in pregnancy
- High levels of oestrogen in blood causes ovulation on day 14

Day 17 - 28:
- Thickening of uterine lining
- Ovary produces progesterone while decreasing production of oestrogen
- Progesterone stimulates the uterine lining to thicken and vascularize to prepare for fertilized egg
- Progesterone prevents ovulation from taking place

Question 14

Ovulation

Answer 14

It is the release of mature egg from the ovary into the oviduct

Question 15

Fertilisation

Answer 15

Occurs when haploid nucleus in sperm fuses with haploid nucleus in egg to form a diploid zygote

Question 16

Early development of embryo

Answer 16

1. Cilia lining in the oviduct sweeps zygote to the uterus
2. As the zygote travels along the oviduct, it undergoes mitosis to form an embryo
3. When the embryo gets imbedded in the uterine lining, implantation has occurred

Question 17

Function of placenta

Answer 17

• It allows oxygen and dissolved food substances to diffuse from the maternal blood into the fetal blood
• It allows metabolic waste products and excretory products such as urea and carbon dioxide to diffuse from the fetal blood into the maternal blood
• it allows antibodies to diffuse from the maternal blood into the fetal blood to protect the fetus
• It produces oestrogen and progesterone to maintain the uterine lining

Question 18

Function of umbilical cord

Answer 18

• Umbilical artery transports deoxygenated and excretory products from the fetus to the placenta
• Umbilical vein
  transports oxygenated blood and dissolved food substances from the placenta to the fetus

Question 19

Function of amniotic sac

Answer 19

• Protects the fetus from injury by absorbing shock
• Supports and cushions the fetus