Blood vessels and tissue fluid Flashcards
(14 cards)
What are the different types of blood vessels and what are their basic functions
- Artery = Carry’s blood away from the heart
- Arterioles = Small branches of artery’s
- Capillary’s = Where gas exchange occurs
- Venules = Small branches of veins
- Veins = Carry blood towards the heart
What different components may blood vessels contain and what do they do?
- Smooth muscle = Contracts to narrow the lumen of vessels
- Elastic tissues = Stretch and recoil to allow the lumen to dilate and return to normal size after pressure change. Also, maintains blood flow
- Collagen = Binds layers together and gives strength
- Endothelium - Single layer of dimple squamous cells (very thin)
On an image where are the different components of blood cells
- Endothelium - Inner most layer (usually just a line)
- Smooth muscle and elastic tissue - Above the Endothelium and bellow collogen
- Collogen - On the outside
What are the structure of arteries
- Narrow lumen
- Thick wall
- High pressure
- More smooth muscle and elastic fibres to veins
- Contains an endothelium layer
What are the structures of veins
- Small lumen
- Low pressure
- Thin wall
- Less smooth muscle and elastic fibres to arteries
- Veins contain valves to prevent the back flow of blood
- Contains an endothelium layer
What is the function of the arterioles
Can reduce blood flow into certain tissues due to the smooth muscles in their walls contracting to narrow the lumen
What is the capillary structure and what do the structures do
What determines the diameter of the lumen
- Form capillary belts where gas exchange occurs
- Small diameter of the lumen to reduce blood speeds and diffusion distance
- Branch between cells to reduce the diffusion distance
- Single layer of endothelial cells to reduce diffusion distance
Size of the red blood cells determines the diameter of a capillary’s lumen
Why does blood not accumulate in the capillaries
They branch so blood does not accumulate due to there being a bigger area
What does blood contain which moves cells
Plasma
What is tissue fluid and what does it do
As blood passes through the capillaries, plasma leaks out between gaps in the endothelial cells in the capillaries and forms tissue fluid
- Surrounds the cells
- Exchange of substances between blood and cells happen via tissue fluid
What is the composition of tissue fluid and plasma like
What do tissue fluids have less of and why
The composition of plasma and tissue fluid is largely the same
Tissue fluid has fewer proteins - because proteins are too large to leak out between endothelial cells so stay in the capillaries
How is hydrostatic pressure created and what is it formed
Its created by systole
Hydrostatic pressure moves fluid out of the capillaries into tissue fluid
How is tissue fluid formed
- At the atrial ends of capillaries
- Hydrostatic pressure is more than the water potential gradient
- Due to the high pressure from systole
- Net movement of fluid out of the capillaries into the tissue fluid
How is fluid taken from the tissue fluid back into the blood
(2 ways)
At the venule end of the capillaries
- Water potential gradient is higher than hydrostatic pressure
- This is due to there being proteins left in the blood creating a large gradient
- Net movement of water back into the capillaries via Osmosis
Formation of lymph
- Excess tissue fluid forms lymph
- Lymph is carried in lymph capillaries (separate to circulatory system)
- Fluid eventually drained back into veins
