L8: Control of Blood Flow Flashcards
What happens to the blood flow after a large meal?
Increased blood flow to stomach & intestines
What happens to blood flow at a localised inflammation?
Increased blood flow to affected areas only
What happens to blood flow during diving?
Reduced blood flow to skeletal muscle, skin, kidneys, GI tract
What happens to blood flow to brain & heart during diving?
Maintained
What happens to the blood flow during aerobic exercise?
Increased blood flow to skeletal & cardiac muscle
Decreased blood flow to kidneys, GI tract
What happens to blood flow to brain during aerobic exercise?
Maintained
How can blood flow in some tissues be increased while at the same time others are decreased?
Different organs use different mechanisms or a combination of mechanisms for control of blood flow
Equation for blood flow?
Flow = Pressure / Resistance
What happens to resistance & blood flow during VASOCONSTRICTION?
Resistance INCREASED
Blood flow DECREASED
What happens to resistance & blood flow during VASODILATION?
Resistance DECREASED
Blood flow INCREASED
4 mechanisms for blood flow control1
1) Sympathetic (neuronal) control
2) Endocrine control
3) Local metabolic control
4) Local myogenic vs metabolic control
Where is sympathetic control of blood flow important in the body?
Muscle, skin, kidney, GI tract
How are arterioles constricted at rest?
Partially constricted
What happens to arterioles & blood flow when MORE noradrenaline is released?
Arterioles constrict MORE
Blood flow REDUCED
What happens to arterioles & blood flow when LESS noradrenaline is released?
Arterioles constrict LESS
Blood flow INCREASED
Where are vasoactive hormones secreted into?
Blood
What are vasoactive hormones?
Hormone found in the pancreas, intestine & CNS
What is active hyperaemia?
Increased blood flow
Why is blood flow increased during active hyperaemia?
An organ/tissue requires more O2 because it is MORE METABOLICALLY ACTIVE
What are blood flow controlled by?
Metabolites