Week 3 - Lesson 1 (Part 5) Flashcards
How is the blood flow to the body tissues and organs normally adjusted?
By changes in the degree of vasoconstriction
Where does vasoconstriction occur?
In the arterioles according to the tissues needs at a given point in time
What are the arterioles considered in the vascular tree?
Stopcocks
- principle point of resistance to blood flow in the circulatory system
Where does blood pressure take the biggest drop?
At the stopcock in the arterioles of the vascular tree
Autoregulation
Is the ability of most vascular beds to constrict in response to a rise in blood pressure and dilate in response to a fall in blood pressure
- vasoconstriction/vasodilation
What is phenomenon called of autoregulation?
Reactive hyperemia
Reactive hyperemia
Increase in blood flow which follows restoration of arterial inflow to a previously ischemic limb
What is an example of reactive hyperemia?
During exercise induced increased heart rate and vasodilation of arterioles to allow more flow to muscular branches
What happens to the diameter in vasoconstriction?
It decreases
- SVR increases
What happens to the diameter in vasodilation?
It increases
- SVR decreases
What causes high arterial pressure?
High volume of blood in the large and medium sized arteries
How is large volumes preserved?
By maintaining a balance between the amount of blood that enters and leaves the arterial tree
What is the amount of blood entering determined by?
Cardiac output
What is the amount exiting determined by? (2)
- Arterial pressure
- Total peripheral resistance
- dependant on status of microcirculation
Cardiac output
How well the heart is working
