7- Mass Transport Flashcards
Cardiac cycle stages (8)
1) Blood from L flows into left A, blood from B flows into right A simultaneously
2) A contract increasing pressure in A
3) Blood is forced into the V
4) Atria relax & V contract
5) pressure in V increases, shutting AV valves
6) blood in V forced out & out of heart through pulmonary artery or aorta
7) -Blood in PA & A is at high pressure> this pressure shuts the semi-lunar valves
8) Both V & A relax & AV valves reopen
Arteries vs veins (5)
A=Walls of thick muscle (for H blood pressure)
V= Walls of thin muscle (for L blood pressure)
A&V= elastic in walls
A= folded endothelium (allows to stretch) V= valves (to prevent backflow)
Role of arterioles in controlling direction of blood=
contraction of arterioles can restrict blood flow, relaxation of arterioles allows blood flow
Capillary structure (adapted for exchange)=(2)
-thin walls-1 cell thick- (short diffusion distance)
pass close to body cells (to allow exchange between blood & organs)
Benefits of Capillary beds
create a large SA for exchange
where is tissue fluid found?
surrounds cells in the body
what is tissue fluid composed of?
O2, H2O & nutrients
Capillaries & Tissue Fluid process (5)
- Blood enters C from arterioles, resulting in high HYDROSTATIC pressure (at arterial end)
- High pressure creates a pressure gradient
- Molecules forced out down PG (forming TF)
- Large molecules remain in C, lowering WP
- At venule end, low HP and WP so water re-enters via osmosis (not all)
- Excess TF absorbed into lymphatic system
Risk factors of cardiovascular disease (3)=
- High blood pressure
- Smoking
- Diet high in saturate fats
Process of atheroma formation= (2)
1)-deposition of WBC & lipids can
damage endothelium of arteries.
-If continued deposition, they form , a hard, fibrous plaque
2)-As plaque builds the lumen becomes narrower (> this restricts blood flow & increases BP)
Atheroma’s can increase risk of =
- Aneurysms (swollen elastic fibres
of artery wall) - Thrombosis (burst artery wall)
Function of haemoglobin:
carries O2 from lungs around the body
Structure of haemoglobin (3)
- Composed of 4 polypeptide chains
- Each polypeptide has a haem group (prosthetic group attached to protein)
- The haem group contains an iron ion
What happens when the first O2 molecule binds to haemoglobin?
the protein undergoes a conformational change which allows other O2 molecules to bind more easily
What happens when the first O2 molecule binds to haemoglobin?
the protein undergoes a conformational change which allows other O2 molecules to bind more easily
