Circulatory system Flashcards
What are the two things that the circulatory system is made up of?
The heart and blood vessels
What are the 4 types of blood vessels?
Arteries
arterioles
veins
capillaries
What are the 3 main arteries?
Pulmonary artery
Aorta
Renal artery
Where does the pulmonary artery carry blood from?
Heart
Where does the pulmonary artery carry blood to?
Lungs
Where does the aorta carry blood from?
Heart
Where does the aorta carry blood to?
Body
Where does the renal artery carry blood from?
Body
Where does the renal artery carry blood to?
Kidneys
What are the three main veins?
Pulmonary veins
Vena cava
Renal vein
Where does the pulmonary vein take blood from?
Lungs
Where does the pulmonary vein take blood to?
Heart
Where does the vena cava take blood from?
Body
Where does the vena cava take blood to?
Heart
Where does the renal vein take blood from?
Kidneys
Where does the renal vein take blood to?
Vena cava
What type of blood does the vena cava carry?
Deoxygenated
What type of blood does the aorta carry?
Oxygenated
What type of blood does the pulmonary artery carry?
Deoxygenated
What type of blood does the pulmonary vein carry?
Oxygenated
Why does the aorta have a high pressure?
It has to take the blood all around the body
Why does the vena cava have a low pressure?
Its the final blood vessel that takes blood to the heart
What are the walls of arteries like?
Thick and muscular
Elastic tissue
In arteries, what helps to maintain a high pressure?
The elastic tissue recoiling as the heart beats
The inner lining is folded
What are arterioles?
Smaller vessels formed from arteries that form a network throughout the body
What are characteristics of arterioles?
Muscles contract to restrict blood flow or relax to allow full blood flow
What is the lumen and tissue like in veins?
Wide lumen
Not very elastic
What are the valves in veins needed for?
to stop the blood flowing backwards
What are capillaries?
Branches of arterioles
What are the features of capillaries and how do they benefit their purpose?
Found near cells in exchange tissues Thin walls (one cell) so theres a short diffusion pathway Large number of them - increase surface area
What is a capillary bed?
Network of capillaries in tissues
What is tissue fluid?
The fluid that surrounds the cells in tissues
What is tissue fluid made of?
Molecules that leave blood plasma
eg. oxygen, water and nutrients
How do substances move out of the capillaries and into the tissue fluid?
Pressure filtration
What does the difference in hydrostatic pressure between capillaries and tissue fluid mean?
Overall outward pressure forces fluid out of the capillaries and into the spaces around the cells which forms tissue fluid.
What does tissue fluid not contain?
Large proteins or red blood cells
What can cells take from the tissue fluid?
Oxygen and nutrients
What does a capillary bed consist of?
Arteries, capillary, venule
What is hydrostatic pressure?
The pressure exerted by a liquid
What is the hydrostatic pressure like at the start of the capillary bed?
There is high pressure in the capillaries and low hydrostatic pressure in the tissues
How is tissue fluid formed?
There is high hydrostatic pressure in the capillaries and low hydrostatic pressure in the tissues. This causes the fluid to be forced out of the capillaries around tissue forming tissue fluid
What happens at the end of the capillary bed?
There is low hydrostatic pressure in the capillaries. The water potential in capillaries is lower than the tissue fluid due to a high number of plasma membranes.
What substance is reabsorbed into the capillaries &
by what process?
Some water
Osmosis
What is the lymphatic system?
A network of tubes which transports excess tissue fluid back into the circulatory system
Describe how tissue fluid is returned to the circulatory system (3 Marks)
1) Capillaries inside tissue
2) High pressure forces water out
3) Water potential in cell decreases to a point where the tissue fluid has more water so the water goes back into the cell
Explain how the highest blood pressure is produced in the left ventricle
Left ventricle has thick muscle so it can produce a high blood pressure as it can push forcefully
