B4 - Organising Animals and Plants - 4.1 The Blood
- Created by: E.Grace
- Created on: 23-04-20 10:21
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- B4 - Organising Animals and Plants
- 4.1 - The Blood
- The Components of the Blood
- Blood is a unique tissue
- Based on a liquid called plasma
- Plasma carries red blood cells, white blood cells and platelets suspended in it.
- Also carries many dissolved substances around your body
- Plasma carries red blood cells, white blood cells and platelets suspended in it.
- Average person has 4.7 - 5L of blood
- Based on a liquid called plasma
- Blood is a unique tissue
- The Blood Plasma as a Transport Medium
- blood plasma is a yellow liquid
- plasma transports all of your blood cells and some other substances around your body
- waste carbon dioxide produced by the cells is carried to the lungs
- Urea formed in liver from breakdown of excess proteins is carried to kidneys where it's removed from blood to form urine
- small soluble products of digestion pass into plasma from small intestine and are transported to the individual cells
- blood plasma is a yellow liquid
- Red Blood Cells
- more red blood cells than any other type of blood cell in your body
- about 5 mill in each cubic millimetre of blood
- these cells pick up oxygen from the air in your lungs and carry it to the cells where it's needed
- Adaptations
- are biconcave discs - being concave (pushed in)on both sides
- gives then an increased surface area to volume ratio for diffusion
- packed with a red pigment called haemoglobin that binds to oxygen
- have no nucleus - making more space form haemoglobin
- are biconcave discs - being concave (pushed in)on both sides
- more red blood cells than any other type of blood cell in your body
- White Blood Cells
- much bigger than red blood cells and there are fewer of them
- have a nucleus
- form part of the body's defence system against harmful microorganisms
- some white blood cells (lymphocytes) form antibodies against microorganisms
- some form antitoxins against poisons made by microorganisms
- others (phagocytes) engulf and digest invading bacteria and viruses
- Platelets
- small fragments of cells
- have no nucleus
- are very important in helping the blood to clot at the site of a wound
- blood clotting is a series of enzyme-controlled reactions that result in converting fibrinogen into fibrin
- produces a network of protein fibres that capture lots of red blood cells and more platelets to form a jelly-like clot that stops you bleeding to death
- the clot dries and hardens to form a scab
- protects the new skin as it grows and stops bacteria entering the body through the wound
- blood clotting is a series of enzyme-controlled reactions that result in converting fibrinogen into fibrin
- Key Points
- The blood, blood vessels and heart make up the human circulatory system which transports substances to and from the body cells
- Plasma has blood cells suspended in it and transports proteins and other chemicals around the body
- Your red blood cells contain haemoglobin that binds to oxygen to transport it from the lungs to the tissues
- White blood cells help to protect the body against infection
- Platelets are cell fragments that start the clotting process at wound sites
- What does blood do?
- transport
- transports substances from one part of the body to another
- protection
- helps to defend against diseases
- regulation
- keeps conditions right for the working of our cells
- transport
- The Components of the Blood
- 4.1 - The Blood
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