Blood Pressure, Heart Rate, Blood Flow, Etc Flashcards
Sympathetic control of heart is between which vertebral levels?
T1-T4/5
What sympathetic ganglia control heart rate?
Middle and inferior cervical
Sympathetic does what in the heart?
Increases rate of contraction, speed of conduction, and force of contraction
Increase speed on conduction aka?
+ dromotropism
Increase speed of contraction aka?
+ chronotropism
Increase force of contraction aka?
+ inotropism
How is the parasympathetic control of heart done?
Via vague nerve cardiac branches
What happens to hear under parasympathetic control?
Decreased rate of contraction, speed of conduction, and force of contraction.
Sympathetic and parasympathetic control increases/decreases HR by increasing/decreasing which phase?
Phase 4
Sympathetic and parasympathetic control increases/decreases conduction velocity by increasing/decreasing what?
PR interval
Sympathetic and parasympathetic control increases/decreases force of contraction by increasing/decreasing what in which phase?
Ca++ influx
Phase 2
Blood pressure =
CO X peripheral resistance
CO is the product of what?
Stroke Volume X HR
CO = 70 ml X 70 beats/min = what?
5 liters/min
Blood pressure may be affected by what three things?
HR
Peripheral resistance
Stroke volume
What are two mechanisms of BP control. Which is fast and which is slow? Why?
baroreceptors - fast - neurotransmitter
renin-angiotensin-aldosterone - slow - hormonal dependent
Where are baroreceptor located?
Carotid sinus and aortic arch
Baroreceptor sense what?
High pressure
Baroreceptor relay info via what? To where?
Afferent in CN IX and X
medulla
A drop in BP will cause heart rate to do what?
increase
An rise in BP will cause heart rate to do what?
decrease
The reflex response to a rise or drop in BP is via what?
autonomic nervous system
Where are low pressure baroreceptor located?
SVC, IVC, and right atrium monitors
Poiselle’s Law: Peripheral resistance (PR) is directly proportional to what?
Viscosity of blood and length of vessel
Poiselle’s Law: PR is inversely proportional to what?
Radius of vessel to the 4th power
If blood vessel radius decreases by half then …
Resistance increases by a factor of 16
The greatest resistance in the vascular system is offered by what?
arterioles
What law states that pressure within a blood vessel is related the tension, size, and shape of the vessel?
La Place’s Law
La Place’s law governs what?
Blood flow through a tubular structure
Blood flow is _______ proportional to the diameter of the blood vessel.
inversely
Blood flow in a normal vessel is _____ and _____.
Smooth and laminar
As the diameter of a vessel becomes smaller, resistance is ________.
increased
What percentage of blood flow is in the venous system at any one time?
60%
% in the artery system at any one time?
40%
What percentage blood is in the arteries and arterioles?
20%
What percentage of blood is in the pulmonary system?
15%
What percentage of blood is in capillaries?
5%
Blood flow is greatest where?
Arteries and veins
Blood flow is least where?
capillaries
