Blood vessels Flashcards
what are the 5 different types if blood vessels
1) arteries
2) arterioles
3) capillaries
4) venuels
5) Veins
all in that order
where do arteries carry blood
how are the arteries adapted to to handle blood at high pressures
Away from the heart, to the rest of the body
- Thick and muscular walls, and have elastic fibres to recoil as the heart beats
why does the arteries have endothelium
to allow the artery to expand, and help maintain high blood pressures
what type of blood does arteries carry and what type of artery carries deoxygenated blood
- Most arteries carry oxygenated blood AWAY from the heart
- BUT pulmonary arteries carry DEoxygenated blood to the lungs
What do arteries branch into:
what is the purpose of smooth muscle
- Arteries branch into arterioles, which are MUCH SMALLER than arteries
- arterioles have a layer of smooth muscle, but much less elastic tissue
- smooth muscle, means they can expand or contract, therefore controlling the amount of blood which flows to the tissue.
What do arterioles branch into:
Capillaires: THE SMALLEST TYPE OF BLOOD VESSELS, substances like glucose and oxygen are exchanged between cells and capillaries
- Adapted for efficient diffusion as they are only one cell thick
what do capillaries branch into:
Venuels
- very thin walls and contain some muscle cells .
what do Venuels branch into:
Veins
Take blood BACK TO THE HEART under low pressure
- wider lumen
- very little elastic or muscle tissue
- contain valves to stop the blood from flowing backwards
ALL VEINS CARRY DEOXYGENATED BLOOD
EXCEPT
for pulmonary veins which carry deoxygenated blood AWAY from the lungs and to the heart.
What is the tissue fluid made from
Made from substances that leave the blood plasma
made up of: EG, oxygen, water and nutrients
- tissue fluid does not contain red blood cells or large proteins, because they are too big to diffuse out the capillary walls.
what is the purpose of the tissue fluid
to take in oxygen and nutrients from it, and release metabolic waste into it
what is a capillary bed
a network of capillaries in an area of tissue
What is pressure Filtration
When substances in a capillary bed move out of the capillaries into the tissue fluid.
Pressure Filtration:
1) At the start of the capillary bed hydrostatic pressure in the capillaries is greater than in the tissue fluid, this difference in Hydrostatic pressure forces fluid out of the capillaries and into the spaces around the cells, forming tissue fluid.
2) As fluid leaves Hydrostatic pressure reduces in the capillaries ( low hydrostatic pressure close to the venules)
3) At the venule end of the capillary bed, the water potential in the capillaries is lower than the water potential in the tissue fluid due to fluid loss from the capillaries and high oncotic pressure.
- This means some water RE-ENTERS the capillaries from the tissue fluid at the venule end by osmosis , to help out the low water potential
what is oncotic pressure
tendency for water to move FROM tissue fluid to capillary bed
what happens to excess tissue fluid that doesn’t re-enter the capillaries
Gets returned to the blood through the lymphatic system
a drainage system sort of thing made up of lymph vessels
