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Biology
Blood and Organs - Coggle Diagram
Biology
Blood and Organs
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3) Vaccination
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Vaccination usually involves injecting dead or inactiye pathogens into the body.
These carry antigens, so even though they're harmless they still trigger an immune response
4) Blood vessels
Blood vessels are designed for their function
There are three different types of blood vessel:
Arteries - There carry the blood away from the heart
Capillaries - There are involved in the exchange of materials at the tissues
Veins - These carry the blood to the heart
Arteries carry blood under pressure
The heart pumps the blood out at high pressure so the artery walls are strong and elastic.
The elastic fibres allow arteries to expand
The largest artery in the body in the aorta
Capillaries are really small
Arteries branch into capillaries.
Capillaries are really tiny - too small to even see.
They have permeable walls, so substances can diffuse in and out.
They supply food and oxygen, and take away wastes like CO2
Veins take blood back to the heart.
Capillaries eventually join up to form veins
The blood is at lower pressure in the veins so the walls don't need to be as thick as artery walls.
They have a bigger lumen than arteries to help the blood flow despite the lower pressure
The largest vein in the body is the vena cava.
5) The Heart
Exercise increases Heart rate
When you exercise, your muscles need more energy, so you respire more
You need to get more oxygen into the cells and remove more carbon dioxide.
Exercise increases the amount of carbon dioxide in the blood.
High levels of blood CO2 are detected by receptors in the aorta and carotid artery.
These receptors send signals to the brain
The brain sends signals to the heart, causing it to contract more frequently and with more force
The hormonal system also helps to control heart rate
When an organism is threatened, the adrenal glands release adrenaline.
Adrenaline binds to specific receptors in the heart. This causes the cardiac muscle to contract more frequently and with more force, so heart rate increases and the heart pumps more blood.
This increases oxygen supply to the tissues, getting the body ready for action
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