Exam 1: Cardiovasular Flashcards
What does Cardiac Output X TPR =
Blood Pressure
How do you calculate Cardiac Output
Heart Rate x Stroke Volume
What response does the A1 receptor prompt?
Vasoconstriction
What response does the B2 receptor prompt?
Vasodilation
What response does the B1 receptor prompt?
Increased HR
What receptor will lower the HR?
M2 (vagus)
What response does the M (vascular) receptor prompt?
Vasodilation (So does B2)
Which two receptors are not innervated?
B2 and M (vascular)
The two receptors for vasodilation
What effect does A1 vasoconstriction have on the CV System?
Increase TPR
Increase BP
What does TPR stand for?
Total Peripheral Resistance
What effect does the increased HR from a B1 stimulation have on the CV System?
Increased CO
Increased BP
What two receptors have the ability to Increase BP?
A1 & B1
What Three receptors can lower BP?
B2
M
M2
What is the effect the B2 Vasodilation has on the CV system (Same for M [vascular])
Decrease TPR
Decrease BP
What is the effect the M2 (Vagus) receptor’s decrease in heart rate has on the CV system?
Decrease CO
Decrease BP
Where are the A1 receptors found
vasculature on the systemic side (arteriole side)
Where are the B1 receptors found?
In the cardiac tissue
Where are the B2 receptors found?
In the arteriole vasculature just like the A1 receptors…they promote the opposite effect of the A1 receptors
If the B2 and M (vascular) receptors are not innervated, then how do they get stimulated?
By EPI from the Adrenal Medulla
Why are B2’s less important than A1 and B1 receptors?
Because they are not innervated by neurons
What is tone?
Basal release of transmitters during resting conditions
What is resting BP and HR?
120/80 @ 70 BPM
What is BP and HR with no tone?
60/40 @ 75 BPM
Why does an athlete have a low resting HR?
Because they have a very high vagal (parasympathetic) tone
Why does you HR = 75 with NO tone, and less (70) with tone?
Because Vagal tone is -10 bpm and Beta1 tone is +5
Net effect is -5 bpm with tone
Where is most of the tone coming from under resting condition?
NE on the A1 receptors in the vasculature
When the stretch receptors detect an increased in BP what signal is sent out
Strong Vagus (PS) tone
Weak B2 tone
Together they decrease TPR and lower BP
When the stretch receptors detect and decrease in BP what signal is sent out?
Strong increase in NE to A1
Weak increase to B1
This will increase TPR and HR increasing BP
Isoproterenol is an agonist for which receptors?
B1 and B2
What effect will a low dose of isoproterenol have on the Pulse rate, BP, and TPR?
B1 - Increases HR –> Increases CO –> Increase in Systolic BP
B2 - Lowers TPR –> Decrease in Diastolic BP
Net effect = Increased Pulse Pressure….and the reflex arc does not care about Pulse Pressure
What effect will a low dose of EPI have on the Pulse Rate, BP, and TPR?
A1 - Increases TPR –> Increases Diastolic BP
B1 - Increases HR –> Increases CO –> Increases Systolic BP
B2 - Decreases TPR –> Decreases Diastolic BP
Net effect = Slight vasodilation because EPI has more effect on B2 at low doses…no rxn from reflex arc
What effect will a low dose of NE have on the Pulse Rate, BP, and TPR?
NE effects A1 more than B1/B2
So there will be a large Increase in TPR so there will be an increase in Diastolic BP
NE is a very weak B2 agonist so there will be a stronger signal to increase HR/CO so Systolic BP will increase as well.
Net increase will be an increase in BP but a decrease in HR due to the reflex action overpowering NE’s effect on B1
