B3W3 Flashcards
Regulation of MAP (intrinsic v extrinsic types)
Intrinsic:
Autoregulation
Metabolic
Myogenic
Endothelial
Extrinsic:
Baroreceptor reflex
Lung Reflex
Chemoreceptors
Muscle metaboreceptors
What are the 4 types of intrinsic MAP regulation and what do they do
- Endothelial (NO/endothelian)
- Myogenic (stretch leading to vasoconstriction)
- Autoregulation (maintaining local flow)
- Metabolic (K, O2, CO2, ADP, ATP, H, Adenosine levels)
What are the types of extrinsic regulation (short term vs long term)
- short term (baroreceptors/chemoreceptors)
- long term through renal stimulation
Vascular smooth muscle in systemic circulation ONLY react to ….?
sympathetic innervation from a1 receptors for vasoconstriction
Vascular smooth muscle in pulmonary circulation ONLY reacts to …..?
sympathetic innervation from B2 receptors for vasoconstriction
Cardiac muscle short term innervation is innervated by ……
both parasympathetic and sympathetic. HR is innervated by parasympathetic, contractility innervated by sympathetic
Are baroreceptors high or low pressure sensors?
HIGH. THEY SENSE HIGH PRESSURE
Where are the baroreceptors located
aortic arch, carotid
Difference between the carotid and aortic arch pressure sensors
carotid = lower threshold, more sensitive
Stimulus, Pathway, Response, Effect and Goal of Baroreceptors
stimulus: high pressure from increase stretch
pathway: increases in BP increases stretch, TRPC1 stretch sensitive non selective cation channels open, depolarization, increased firing of sensory nerves to the NTS
Response: increases PNS output and decreases SNS
effect: bradycardia, vasodilation, decreased contractility
Goal: restore MAP
How does increasing and decreasing stimulation to baroreceptors work
they are tonically active (always active) but by increasing frequency of firing, different response
How do baroreceptors decrease MAP
stretch receptors no longer have stimulus, decreased firing rate to NTS, parasympathetic decreases to increase HR, sympathetic increases to increase HR, contractility vasoconstriction and venous return
How do the kidneys increase MAP
stimulation of renin release, catalyzes the RAAS cascade to increase ADH, aldosterone, increase water and salt retention to maintain blood volume
What does the cardiopulmonary reflex arch respond to ?
low pressure/high volume of blood
Location, stimulus, activation/response, effect, goal of the cardiopulmonary reflex
location: veins, arteries, pulmonary arteries on the venous time
stimulus: increasing blood volume, increasing preload, increasing cardiac filling pressure (LVEDP)
Activation/response: decreases in sympathetic output to increase ANP (antinaturetic peptide which will increase excretion) and decrease ADH (antidiuretic hormone which produces high urine output)
Effect: Vasodilation of renal circulation, decreases in SV (which increases more Na H2O excretion time) increases HR
goal - maintain volume by excreting urine
Peripheral chemoreceptor Circuit
Hypoxic conditions
location: carotid body/aortic body
stimulus- decreased O2, increased CO2 and decreased pH
activation: increases sympathetic and decreases sympathetic
effect: leads to vasoconstriction, bradycardia, hyperventilation
central chemoreceptor control
hypercarbic drive
location: brain and medulla
stimulus: increases in CO2, decreases in pH of the interstitial fluid of the brain
activation: sympathetic
effect: peripheral vasoconstriction with hyperventilation
Exercise reflex circut
Location: muscle afferents of skeletal muscles
Stimulus: metabolites (K, H, Adenosine)
Response: increases in sympathetic responses, decrease in parasympathetic responses
effect: tachycardia, vasodilation of active muscles, vasoconstriction of inactive muscles
Lung Reflex
Location: lung
Stimulus: lung inflation
response: decreases sympathetic innervation leading to vasodilation of muscles, decreases parasympathetic responses (increases HR)
Effect: vasodilation of vessels and tachycardia
What are the two values and which way are they pointing on the cardio vascular curve?
Line going down is vascular function
line going up is cardiac function
The y axis = CO
x axis = (R) atrial pressure
What does the intersection of the vascular and cardiac curve mean?
It is the steady state that is maintained by the body to maintain vascular and cardiac function
What are the three values that can change the cardiac vascular curve
increase/decrease in ionotrophy
change in blood volume
change in TPR
If there are changes in ionotropic effects, which line of the graph changes and how does it move?
Changes the cardiac function by:
increasing ionotropy = moving it up
decreasing ionotrophy = moving it down
If there are changes in blood volume, which line of the graph changes and how does it move?
The vascular function curve moves and it will:
increasing blood volume: move it up
decreasing blood volume: move it down
