B3 - Circulatory System Flashcards
Describe what happens to the blood in the heart
It comes into the vena cava, and is pumped through the right atrium, right ventricle and out of the pulmonary artery to be oxygenated
It comes back into the heart via the pulmonary vein and is pumped through the left atrium, left ventricle and out through the aorta to the rest of the body
What is the heart a double circulatory system?
One circuit goes around the body and one goes from the heart to the lungs and back
What is unusual about heart diagrams?
The left of the diagram is the right atrium and ventricle and vice versa
How the atria and ventricles pump the blood around the circulatory system?
They are made from muscle tissue that contracts which pumps the blood
What are valves and where are they found in the circulatory system?
They stop blood from flowing in the wrong direction
They are found between each atrium and ventricle and before the pulmonary artery and the aorta
What are the 3 different types of blood vessel and what are their basic functions?
Arteries carry blood away from the heart
Veins carry blood to the heart
Capillaries are involved in the exchange of materials and split off from the arteries and veins
What are the 3 properties of an artery?
They are made from thick layers of muscle to make them strong and elastic fibres to allow them to stretch
Their walls are very thick
They pump blood away from the heart at high pressure
What are the 3 properties of capillaries?
Arteries branch into capillaries and capillaries join back up into veins
They carry blood very close to every cell in the body to exchange substances with them
They have thin, permeable walls so that substances can diffuse in and out
What are the 3 properties of veins?
They carry blood back to the heart at low pressure
They have thinner walls and larger centres than arteries because the pressure is lower
They have valves to stop blood flowing in the wrong direction
What are the 4 components of blood?
Red blood cells
White blood cells
Platelets
Plasma
What do red blood cells do?
They carry oxygen from the lungs to every cell in the body
Why do red blood cells have a concave shape?
So that the surface area is larger meaning that oxygen is absorbed better
What don’t red blood cells have a nucleus?
So that more oxygen can be held as there is more space without the nucleus
What is haemoglobin?
A red pigment in red blood cells that combines with oxygen in the lungs to form oxyhaemoglobin
In body tissues, oxyhaemoglobin is split back into its constituents
What 3 things do white blood cells do?
They can change shape to engulf microorganisms
They can produce antibodies and antitoxins to fight microorganisms
They can detect unfamiliar microorganisms with the antigens on their surface