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Circulatory system of a Mammal - Coggle Diagram
Circulatory system of a Mammal
Low surface area:volume
The circulatory system is made up of the heart and blood vessels. The heart pumps blood through the blood vessels (arteries, capillaries, veins) which go all through the body
Two circuits - one that takes blood from the heart to the lungs and then back to the heart. The other takes blood around the rest of the body
Heart has its own blood supply, the left and right coronary arteries.
Arteries
Carry blood from the heart to the rest of the body
Walls are thick and muscular and have elastic tissue meaning they can stretch and recoil. This helps maintain a high blood pressure
Inner endothelium is folded
Arteries divide into arterioles
Veins
Take blood back to the heart under low pressure
Wide lumens with very little elastic or muscle tissue
Contain valves which prevent any back flow of blood
Veins carry deoxygenated blood, except the pulmonary vein which carries oxygenated blood to heart from the lungs
Capillaries
Walls are only one cell thick for a short diffusion pathway
Used for the exchange of substances
There are lots of them to increase surface area
Tissue fluid formation
Hydrostatic pressure is higher in the capillary than it is in the tissue
Because of this difference, fluid is forced out of the capillary and into the area surrounding the cell
The hydrostatic pressure is now much low in the venule end of the capillary
Due to loss of water and an increase in the conc of plasma proteins, the water potential at the venule end is now low
Some water re-enters the capillary via osmosis