Flashcards in Heart Physiology 2 Deck (45):
What are the functions of the circulatory system?
1) Distribution of dissolved gasses
2) Waste removal
3) Chemical signalling
4) Mediate inflammatory, immune responses
5) Conserve or release heat from skin surface
What is a portal system?
Two capillary beds in series
EG: In kidneys, stomach, liver
Which blood vessels have elastic tissue?
Which blood vessels have smooth muscle?
Arteries, arterioles, veins
Where is the highest and lowest mean systemic blood pressure?
Vena cavae (lowest)
Where is blood flow slowest?
What is the Windkessel effect?
Reduction in arterial pressure changes during systole and diastole (heartbeat)
Caused by elastin in walls of arteries, walls distend in systole, recoil in diastole
Where is the Windkessel effect relevant?
How to proteins move across the membranes of capillaries?
Which tissues make up the walls of arteries?
Which tissues make up the walls of veins?
Which tissues make up the walls of arterioles?
Which tissues make up the walls of capillaries?
Which tissues make up the walls of venules?
Mean arterial diameter
Mean venous diameter
Mean arterial wall thickness
Mean venous wall thickness
Proportion of blood stored in systemic veins
Proportion of blood stored in arteries
How far are most cells from a capillary?
What is bulk flow?
Overall movement of fluid between blood and tissues
Difference between hydrostatic pressure and colloid osmotic pressure
What is absorption?
Movement of fluid from interstitium into capillaries
What is filtration?
Fluid movement out of capillaries into interstitium
What is oedema?
Interstitial fluid accumulation
Difference in solute concentrations between blood and interstitial fluid
Electrolyte balance the same
Proteins in blood, too large to get into interstitial fluid
What are the pressures influencing bulk flow?
Osmotic pressure (pi) - Movement into capillary
Hydrostatic pressure (P) - Movement out of capillary
What is colloid (or oncotic) osmotic pressure?
Osmotic pressure caused by proteins in the blood that can't penetrate the endothelium of capillaries
What is the plasma oncotic pressure vs the interstitial fluid oncotic pressure?
What is hydrostatic pressure?
The pressure exerted by the blood on the blood vessel walls.
Decreases with length
What is hydrostatic pressure in capillaries at the arteriolar end?
What is the hydrostatic pressure in capillaries at the venous end?
What is the hydrostatic pressure in the interstitial fluid?
What is the bulk flow at the arterial end of a capillary?
What is the bulk flow at the venous end of a capillary?
Which pressure favours filtration?
Which pressure favours absorption?
Colloid osmotic pressure
Is colloid osmotic pressure constant, or does it change with capillary length?
Is hydrostatic pressure constant, or does it change with capillary length?
Decreases with capillary length
What is the net fluid movement of fluid per day?
3L out of capillaries per day
Where does the excess fluid filtrated into the interstitial fluid go?
Into the lymphatic system
Where do the largest lymph vessels empty?
Into the venous system
Where the left/right subclavian veins join internal jugular veins
What plays a large role in pumping lymph?
Skeletal muscle pump
Roles of lymphatic system
1) Return fluid and proteins filtered back into circulation
2) Pick up fat absorbed in small intestine, transfer to circulatory system
3) Immune system