Male and Female reproductive systems of mammals
Male and Female
Reproductive Systems of
Mammals
1. Male reproductive system
• The two testes - The sexual glands where sperm cells and a male hormone are produced.
• The two sperm ducts - The pathways for the sperm cells from the testicles to the urethra.
• The seminal glands - Produce liquid called semen. It is rich in nutrients important for the sperm cells to move and survive.
• The urethraThe tube that carries urine and sperm to the outside of the body.
• The penisThe organ of copulation
2. Female reproductive system
• The ovaries -The sexual glands where ova and the female hormones are produced.
• The oviducts - The pathway for the ova from the ovary to the uterus and site of fertilization.
• The uterus - The site of the fetus development.
• The vagina - The female organ of copulation.
3. The reproductive cells (gametes)
a/ The male gametes:
Sperm cells b/ The female gametes:
Egg cells (ova)
4. Fertilization
• a/ What is fertilization?- Fertilization is the union of an egg and sperm, usually occurring in the oviduct. The result of this union is the production of a zygote.
• b/ Steps of the formation of the zygote
- The sperm cell penetrates the egg cell by dissolving part of its envelope.
- The nucleus of the sperm cell mixes with the nucleus of the egg cell.
- The zygote is formed.
7. Kinds of fertilization
• a/ External fertilization (in frogs)
- Clasping by the male, stimulates the female to lay 500 to 5000 eggs.
- The male fertilizes the eggs by releasing semen in water .
• b/ Internal fertilization (in mammals)
- The male covers the female.
The male’s penis penetrates the female’s vagina. In this way, the sperm cells are directly introduced into the uterus.
- Fertilization takes place in the oviduct .
8. Kinds of animals according to the eggs development
• a/ Oviparous animals: They lay eggs. These eggs develop outside the female body.
The oviparous eggs are very big and rich in nutrients important for the development of the embryo.
The oviparous females do not have uterus .
Examples: Birds, reptiles, fish
• b/ Viviparous animals: In these animals the fertilized egg develops inside the mother’s uterus. Their eggs are very small and poor in nutrients because the mother provides all the necessary nutrients to the embryo.
Examples: All mammals
• c/ Ovoviviparous animals: They produce eggs rich in nutrients . But the development of the youngsters occurs inside the mothers body , in the oviduct. The ovoviviparous animals do not have uterus .
• Example: The viper
