Exchange And Transport In Animals Flashcards
(38 cards)
Exchange in materials : cells
Cells need oxygen for aerobic respiration
CO2 is a waste product
Exchange of materials : water
Taken up by cells by osmosis
Food molecules diffuse w/ it
The larger the organism, the smaller the surface area is compared to the volume
Surface area : volume ratio
Alveoli adaptations
Thin walls = minimise distance for diffusion
What is around the alveoli?
A capillary
Carbon dioxide in the capillary…
Diffuses into the alveoli air space
Down the concentration gradient
Oxygen from the lungs…
Diffuses into the blood in the capillary
From an area of high concentration to an area of low concentration
What do red blood cells do?
Carry oxygen from the lungs to the rest of the body
Shape of red blood cells
Biconcave disc shape
What is the red pigment in red blood cells called?
Haemoglobin
Containing iron
Why do red blood cells have no nuclei?
Allows more room for carrying oxygen
Types of white blood cells
Phagocytes
Lymphocytes
What do phagocytes?
They change shape to engulf unwanted micro-organisms
This is called phagocytosis
What are lymphocytes?
They produce antibodies + antitoxins
What are platelets?
Small fragments of cells which help blood clotting
What is plasma?
Carries everything in the blood
- R+W blood cells
- hormones
- proteins
Name the 3 blood vessels
Arteries
Capillaries
Veins
Where do arteries take the blood?
Away from the heart
Describe arteries
- thick walls
- thin lumen
- elastic fibres
Why do arteries have thick walls?
Because the blood is under high pressure
Describe capillaries
- one cell thick (permeable walls)
Why are capillaries so thin?
Increases rate of diffusion
Where do veins carry the blood to?
The heart
Describe veins
- thin walls
- larger lumen
- valves
