Please enable JavaScript.
Coggle requires JavaScript to display documents.
Cardiovascular Physiology Lecture 5 (Tonic control of Arteriolar diameter,…
Cardiovascular Physiology Lecture 5
Objective 1
Understand the overall design of the
peripheral circulation
**The Blood Vessels:
->
Arteries
take blood away from the heart
-Elastic walls and thick layers of vascular smooth muscles
-Act as pressure reservoir
->
Veins
take blood back to the heart
-Thin walls of vascular smooth muscle
-Act as volume reservoir
For both: smooth muscle changes diamter
Pressure is proportional to Flow x Resistance
To increase pressure (either increase flow/cardiac input or increase resistance)
Systemic circulation pressures
Pulse Pressure
: systolic pressure-diastolic pressure
Mean Arterial Pressure
: Actual use: diastolic pressure + (1/3) pulse pressure
->Conceptual version: Has to do with CO and resistance in the arterioles (peripheral resistance)
->MAP: mass balance, the volume of blood in the arteries is determined by CO and flow out out (altered by changing peripheral resistance)
Elastic arteries -> store energy from contraction
By storing pressure in contraction, maintain it during relaxation
Sphygmomanometry
Can't hear any sounds
Artery only opens when systolic period
Squeezes artery shut
Turbulent blood flow allows for sound
Inflated to higher than brachial pressure
After diastolic -> no more turbulent blood flow
Regulation of Arteriolar Resistance (arteriols)
Sympathetic Reflexes:
to maintain arterial pressure and regulate blood distribution for homeostatic needs (e.g. temperature regulation)
NE: Vasoconstriction, binds to alpha receptors, causes baroreceptor reflex
Hormones
: either directly or by altering autonomic reflex control (SNS vs. PNS)
Local Control:
matches tissue blood flow with metabolic needs of a given tissue
Adenosine: increase blood flow to match metabolism (vasodilation)
Hyperemia
Increase tissue metabolism
Release of metabolic vasodilators into ECF
Arterioles dilate
Decrease resistance
Increase blood flow
O2 and nutrient supply to tissues increase
As long as metabolism is increased
Example:
Grip strength training
Bi-product: adenosine
Causes dilation
Increase blood flow
O2 to the muscle being used
Tonic control of Arteriolar diameter
Increase NE
As signal rate increases
Vasoconstriction of blood vessel
Decrease NE
As signal decreases
Vasodilation of blood vessels