Difference between veins & arteries
Veins take blood into the heart
Arteries take blood away from the heart
Purpose of circulatory system 3
Move material to and from cells
Help fight diseases
Help stabilise body temperature
Pulmonary circulation
Transports blood to and from the lungs to exchange O2 and co2
Systematic circulation
Transports blood to and from the heart to exchange O2 and co2 with body cells
Effect of exercise on heart rate
- muscles need more energy
- rate of respiration increases
- more oxygen and glucose needed
- heart rate and force of beat increase
Stroke volume
Volume of blood pumped per beat
Effect of stress (anger, fear) on heart rate
Fight or flight response
Adrenalin makes heart beat faster
Effects of adrenalin on heart rate
Adrenaline released from the adrenal glands stimulates the pacemaker to increase heart rate
What is the main function of the placenta
To supply nutrients & oxygen to the foetus & remove waste products
What do leukocytes (white blood cells) do?
Defence against disease
What do phagocytes do
Engulf and digest microorganisms
What do lymphocytes do
Produce antibodies to destroy microorganisms and memory lymphocytes to give us immunity to specific diseases
What is sickle cell anaemia & what causes it
Lack of oxygen in blood caused by sickle cells
Abnormally shaped red blood cells cause haemoglobin to clump
What is iron deficiency & how does it happen
Lack of oxygen due to lack of iron - anaemia
Haemoglobin can’t function properly without enough iron
Little or no clotting factors in blood
Haemophilia
Clotting factor
A protein that works with platelets to form blood clots
How do you treat haemophilia
Inject with clotting factors
What is leukaemia and what causes it
Cancer of white blood cells
Proliferation of abnormal or non functioning white blood cells
Leukaemia symptoms
Can get anaemia - like symptoms
Can’t fight off infections
Arteries adaption for function
Thick muscular walls to smooth out the pulses of blood flow from the heart
Capillaries adaption for function
Have walls that are very thin so that the blood can exchange dissolved food and gases easily with the cells by diffusion
Veins adaption for function
Large to carry blood under low pressure back to the heart
Arteries adaption for function
Thick muscular walls to smooth out the pulses of blood flow from the heart
Capillaries adaption for function
Have walls that are very thin so that the blood can exchange dissolved food and gases easily with the cells by diffusion
Veins adaption for function
Large to carry blood under low pressure back to the heart
Systole
When the heart contracts and forces the blood out around the body and to the lungs
Diastole
When the heart fills with blood
Coronary heart disease
The coronary arteries which supply food & oxygen to the heart itself become narrower or blocked
Why is it called double circulation
Because the blood is circulated round the lungs, returns to the heart and is then circulated round the body, so there are two separate circulation systems
Plasma
The yellow liquid which transports dissolved food molecules, carbon dioxide and urea as well as all the blood cells. It is mainly water
Platelets
Cell fragments which help clot the blood
Coronary heart disease 4
- blockage of coronary artery
- blood supply to area of heart muscle cut off
- less oxygen and glucose reaches heart muscle
- area of heart muscle cannot respire
- > heart attack (angina)
Why is it important to have blood that clots
Less blood loss
Less entry of microbes/pathogens/disease
Deoxygenated blood enters heart through
Vena cava
Takes deoxygenated blood to lungs
Pulmonary artery
Carries oxygenated blood to body
Aorta
Brings oxygenated blood from lungs
Pulmonary vein
Why is the muscular heart wall thicker on the left
Has to pump blood all around the body
Difference between veins and arteries
Arteries are red blood vessels that carry blood away from the heart
Veins are blue blood vessels that carry blood towards the heart
Why do scientists obtain blood samples from a vein rather than from an artery 2
The blood in the vein is at a lower pressure
Veins closer to surface so easier to access
Why is double circulation more efficient
Heart pumps blood twice, so higher pressures can be maintained
Blood travels more quickly to organs
Single circulation description and problem
Blood is pumped from heart to gas exchange organ then directly to rest of body
Blood loses pressure as it passes thru gas exchange organ. It then travels relatively slowly to other organs
How does oxygen enter a red blood cell from the alveoli in the lungs
dissolves in the liquid lining the alveoli, then diffuses down a concentration gradient through walls of alveoli and capillaries into plasma and red blood cells
How does oxygen pass from a red blood cell to an actively restoring muscle cell
Dissolves in the plasma then diffuses down a concentration gradient through the walls of the capillaries into the muscle cells
Veins 3 features
Valves
Thin walls with little muscle
Large lumen