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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 12, Topic 1
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Blood function and composition

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The functions of blood

Transport

Gases: oxygen enters blood at the lungs
Nutrients: enter blood at the small intestine
Waste : urea enters the blood at the liver
Hormones: enters the blood at endocrine gland


Protection
Contain white blood cells and platelet


Regulation
Keeps the amount of water and salts in the cells at the correct level
Helps maintain body temperature

Carbon dioxide levels

Composition of blood

Plasma 

Function:

  • To transport: water proteins, minerals, glucose, amino acids, salts, urea, hormones, carbon dioxide, antibodies

Structure:

The liquid part of blood

Red blood cells 

Function:

To transport oxygen

Structure:

Red blood cells have the following structural adaptations to help them carry oxygen

  • Bi-concave
  • Contain haemoglobin
  • No nucleus
  • No mitochondria

White blood cells 

Function:

Defense against disease

Structure:

  • Colorless
  • Nucleus present

Types:

Monocytes 

  • Produced in the red bone marrow
  • The largest type of white blood cell
  • They function in protection by engulfing bacteria and dead cells

Lymphocytes

  • Produced in the red bone marrow
  • Have a fairly large nucleus
  • They produce antibodies which destroy foreign cells

Platelets 

Function:

Blood clotting

Structure:

  • Cell fragments
  • No nucleus present

Site of production:

  • Red bone marrow