Chapter 7 - Transport in Man Flashcards
Why is there not a need for a transport system in unicellular organisms?
- No part of the cell is far from external environment
- Exchange of materials occurs easily by diffusion
Why is there a need for a transport system in multicellular organisms?
- Larger body, with reduced surface area to volume ratio
- Cells are located deeper in the body, further away from the external environment
- Diffusion is inadequate for transport
Blood is a ________
fluid tissue
Blood is made up of ________, ________, ________ and ________
plasma
red blood cells
white blood cells
platelets
About ____% of blood is made up of plasma (the fluid part) and the other ____% is made up of blood cells and platelets
55
45
Blood is separated into layers through ________
centrifugation
when spun in a high-speed centrifuge, it separates according to relative densities of the components
What is plasma?
A pale yellowish liquid which is 90% water with a complex mixture of various dissolved substances
What are the dissolved substances in plasma? [5]
- Proteins: fibrinogen, prothrombin and antibodies
- Mineral salts: hydrogencarbonates, chlorides, sodium, sulfates and phosphates of calcium
- Food substances: glucose, amino acids and fats
- Waste products: urea, uric acid and creatinine;
- Hormones: insulin
Red blood cells (erythrocytes) constitute ____% of cells in the blood
99
Red blood cells (erythrocytes) are produced in the ________
bone marrow
Red blood cells (erythrocytes) are destroyed at the ________
spleen
Red blood cells (erythrocytes) have a lifespan of ________
3-4 months
What is the function of red blood cells?
To transport oxygen to cells in the body
How is the red blood cell adapted for its function? [4]
- Filled with red pigment haemoglobin: essential for binding oxygen
- Absence of nucleus: allows more haemoglobin to be packed into the cell
- Biconcave shape: increases surface area to volume ratio for efficient uptake of oxygen
- Elastic: able to turn bell-shaped to squeeze through tiny blood capillaries
White blood cells (leucocytes) are ________ in size than red blood cells but ________ in number
larger
fewer
White blood cells (leucocytes) are produced in the ________
bone marrow
White blood cells (leucocytes) are destroyed at the ________
spleen
White blood cells (leucocytes) have a lifespan of ________
a few days
Features of a white blood cell [3]
- Colourless as it does not contain haemoglobin
- Irregular in shape and contains a nucleus
- Mobile: is able to move, change its shape and squeeze through walls of the thinnest blood capillaries
What are the types of white blood cells?
Lymphocytes and phagocytes
Features of a lymphocyte [2]
- Large rounded nucleus
- Small amount of non-granular cytoplasm
Function of a lymphocyte
Produces antibodies to protect the body from disease-causing microorganisms
Features of a phagocyte [2]
- Lobed nucleus
- Granular cytoplasm
Function of a phagocyte
Is able to ingest foreign particles such as bacteria
What are blood platelets (thrombocytes)?
- Not true cells
- Fragments of cytoplasm which are membrane bound
Function of blood platelets (thrombocytes)
Important for the clotting of blood
Blood transfusion: what are antigens?
Proteins found on the surface of red blood cells
Blood transfusion: what are antibodies?
- Found in plasma
- Able to recognise and bind the specific antigens on the red blood cells
Difference between antibodies and antibiotics
Antibodies: proteins that combat infections
Antibiotics: chemicals/medicine used to kill bacteria
Blood type A has antigen ____ on the red blood cell and antibody ____ in the plasma
A
b
Blood type B has antigen ____ on the red blood cell and antibody ____ in the plasma
B
a
Blood type O has antigen ____ on the red blood cell and antibody ____ in the plasma
(no antigens)
a and b
Blood type AB has antigen ____ on the red blood cell and antibody ____ in the plasma
A and B
no antibodies
What happens when Type A blood
is added to Type B blood?
- Antibody a in plasma of recipient binds to antigen A on red blood cells of donor’s blood
- Agglutination (clumping) of red blood cells occurs
What is considered during a blood transfusion?
The effect of the recipient’s plasma on the donor’s red blood cells is considered
Which blood group is the universal donor and why?
Blood type O
- There are no antigens on the donor’s red blood cells, so the antibodies in recipient’s plasma will not react with the red blood cells
Which blood group is the universal acceptor and why?
Blood type AB
- There are no antibodies in the plasma. Hence, no agglutination of red blood cells in donor’s blood will occur.
Blood acts as a ________
transport medium
What are the substances transported by blood?
- Digested food substances
- Excretory products (e.g. urea and carbon dioxide)
- Hormones
- Heat
- Oxygen
Transport of oxygen to body cells
→ Blood passes through lungs, oxygen diffuses from the air sacs in the lungs into the blood (simple diffusion)
→ Haemoglobin combines with oxygen to form oxyhaemoglobin
→ Blood transports oxygen to all the tissues of the body
→ At the tissue cells, oxyhaemoglobin releases the oxygen