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Leaving certificate biology

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  1. Ecology theory
    5 Topics
    |
    1 Quiz
  2. Unit 1
    Nutrient recycling
    4 Topics
    |
    1 Quiz
  3. Ecological relationships and population dynamics
    2 Topics
  4. Human impact on the ecosystem
    2 Topics
  5. Study of a grassland ecosystem
    3 Topics
  6. Responses in the Flowering Plant
    4 Topics
    |
    1 Quiz
  7. Unit 3
    Sexual reproduction in the flowering plant
    1 Topic
  8. The human reproductive system
    3 Topics
  9. The menstrual cycle
    2 Topics
  10. Pregnancy
    2 Topics
  11. The circulatory system
    4 Topics
  12. Blood
    5 Topics
  13. The heart
    5 Topics
Lesson 8, Topic 2
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Sperm and male hormones

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What are sperm ?

  • Sperm are produced in the testes  meiosis and as a result they are haploid with only 23 chromosomes.
    Sperm is a gamete (sex cell)

Sperm structure

Head

  • Contains the nucleus with 23 chromosomes (human haploid number) and an acrosome – needed to penetrate the egg cell at fertilisation

Midpiece 

  • Contains many mitochondria that produce energy needed for movement of the sperm cell towards the egg cell

Tail

  • Responsible for propelling the sperm cell towards the egg

The role of mitochondria in sperm

  • Sperm cells need to swim long distances mitochondria produce energy through respiration to do this

Low sperm count

Causes:

  • Persistent smoking

  • Alcohol abuse

  • Lack of FSH

  • Use of anabolic steroids

  • Use of marijuana

Treatment:

  • Stop taking : Alcohol , marijuana, steroids.
  • FSH may be injected
  • In vitro fertilisation

The male reproductive hormones

  • Hormone: FSH

Site of production: Pituitary

Site of action: Testes

Functions: Stimulates production of sperm

  • Hormone: LH

Site of production: Pituitary

Site of action: Testes

Functions: Stimulates production of testosterone

  • Hormone: Testosterone

Site of production: Testes

Site of action: All around body

Functions: Responsible for secondary sexual characteristics and sperm production