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Yuchen Jiang
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Notes on Transport System in Organisms- Singapore Secondary 1 Biology

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Yuchen Jiang
Created by Yuchen Jiang almost 11 years ago
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Blood
Blood is a fluid tissue (fluid with cells). It is made up of
  • Plasma
  • Red blood cells
  • White blood cells
  • Platelets 
Plasma
Plasma is a pale yellowish fluid that is made up of mainly water
Functions:
  • Transports many dissolved substances (e.g. digested food from intestines to other parts of the body/ hormones which are powerful chemical signals)
  • Remove carbon dioxide and other waste substances produced in body cells
Red Blood Cells
  • Red blood cells are circular and biconcave in shape, this increases the surface area  of the cells for rapid diffusion of oxygen.
  • Red blood cells transport oxygen from the lungs to the rest of the body.

White Blood Cells

  • Colourless and irregular in shape
  • Larger than red blood cells and contains nucleus
  • Produces by bone marrows and destroyed by other white blood cells
  • Life span of a few days
  • Two types- Phagocytes and Lymphocytes
Phagocytes
  • White blood cells that engulf and ingest foreign particles like bacteria
  • This process is called phagocytosis
Polymorph
  • Granular cytoplasm
  • Lobed nucleus
Monocyte
  • Plasma membrane
Lymphocytes
  • Produces antibodies
  • What are antibodies?
Chemical substances produces by the blood to 'fight' against toxins, foreign bacteria and virus.
  • How does antibodies 'kill' bacteria?
Bacteria are clumped together using antibodies, a process called agglutination, to allow easy ingestion by phagocytes
Transport Systems in Organisms
Transport System in Humans

The human transport system is called the circulatory system. It consists of
  • The heart
  • Blood vessels- arteries, veins, capillaries
  • Blood
Lymphocyte
  • Large, rounded nucleus
  • Non granular cytoplasm
List three differences between phagocytes and lymphocytes
Lymphocytes

  • Rounded nucleus
  • Non-granular ctoplasm
  • Antibiotics
Phagocytes

  • Lobed nucleus
  • Granular cytoplasm
  • Engulf and ingest foreign particles
Platelets
  • Fragments of cytoplasm from certain bone marrow cells
  • Play a part in the clotting of blood
  • Contain an enzyme that clots blood
Types of Blood Vessels
Arteries
Carry blood away from the heart
Capillary
Allows exchange of materials between blood and tissue
Vein
Carries blood towards the heart
Artery vs Veins

(1) Structure
  • Arteries have thick and elastic muscular walls
  • What are the thick elastic walls for?
  • The thick muscular walls help to withstand the high blood pressure in the artery
  • The elasticity permits stretching and recoiling of the artery wall
  • These help to push the blood along
  • Veins have semi-lunar valves along their lengths to prevent back flow of blood.
  • Why would there be back flow of blood?
The gravitational pull as blood goes back to the heart from parts of the body that are below the blood
Capillaries

  • Very thin and fragile microscopic vessels
  • One-celled thick walls
  • Connect the arteries to the veins
  • Repeatedly branched out
Artery vs Veins

(2) Presence of Valves
BLOOD
TRANSPORT SYSTEM IN ORGANISMS
Blood vessels