Blood Pressure Flashcards
What is blood pressure?
The force exerted by blood on the inner walls of blood vessels.
What is blood pressure also known as?
Systematic arterial blood pressure.
What causes blood pressure?
Heart forcing the blood through the blood vessels against the narrow peripheral blood vessels.
What are the 3 components that influence blood pressure? (homeostatic control of blood pressure)
1) . Heart activity.
2) . Blood volume and viscosity.
3) . Blood vessels, in particular diameter of the arterioles.
What happens to the heart rate if there is increased/decreased blood pressure?
1) . Increased blood pressure =
- Increased heart rate.
2) . Decreased blood pressure =
- Decreased heart rate.
What changes in the diameter of small arteries increase/decrease blood pressure?
1) . Vasoconstriction =
- increase.
2) . Vasodilation =
- Decrease.
What changes in blood volume increase/decrease blood pressure?
1) . Increased blood volume = increased blood pressure.
2) . Decreased blood volume = decreased blood pressure.
What is the equation for blood pressure control?
Blood pressure = cardiac output x total peripheral resistance.
What does the equation for blood pressure control suggest?
Anything that increase cardiac output/peripheral resistance will increase blood pressure, vice versa.
What is cardiac output?
Total volume of blood pumped out of the ventricle per minute.
How is the cardiac output calculated?
Cardiac output = heart rate x stroke volume.
What is the stroke volume?
Amount of blood ejected from the left ventricle at each contraction.
What is peripheral resistance?
The resistance to blood flow =
- force created by the friction between blood and blood vessel walls.
How is peripheral resistance created?
By the diameter of the blood vessels in the periphery.
What is vasoconstriction? What is it in response to?
Blood vessel diameter decrease =
- responds to increased blood pressure.
What is vasodilation? What is it in response to?
Blood vessel diameter increase =
- responds to decreased blood pressure.
What controls short-term blood pressure?
The nervous system.
What controls long-term blood pressure?
Hormones.
How does adrenaline affect blood pressure?
Increases it very quickly.
Why is the arterial baroreceptor reflex important in the control of blood pressure?
Controls moment to moment arterial blood pressures.
What cardiovascular factors does the arterial barorecptor reflex modify?
- Heart rate.
- Cardiac stroke volume.
- Peripheral vascular resistance.
What system is the most important in regulating the heart rate?
Autonomic.
Which nerves supply the heart?
- Sympathetic.
- Parasympathetic.
Where do the sympathetic/parasympathetic nerves originate?
Cardiac centre in the medulla.
Sympathetic activity speed or slow heart rate?
Speeds it up, vice versa.
How do blood vessels influence influence blood pressure?
Blood pressure increases when blood is forced through narrower vessels, vice versa.
The greater the peripheral resistance…
Higher the blood pressure.
Which group of neurons regulate the diameter of arterioles?
Vasomotor centre =
- in the medulla.
Summarise what peripheral resistance is and how is it regulated?
1) . Force created by the fricton between blood and vessel walls.
2) . Regulated by a group of neurons in the meddula (vasomotor centre).
What is blood pressure directly proportional to, in the cardiovascular system?
The volume of blood.
How is blood volume regulated?
Hormonally.
What hormones regulate blood volume?
- ADH.
- Renin-angiotensin-aldosterone system (RAAS).
Summarise what influences blood pressure?
- Cardiac output.
- Peripheral resistance.
- Blood volume.
How is the short-term control of blood pressure achieved?
MEDULLA (brain stem).
- Cardiac centre.
- Vasomotor centre.
What causes the cardiac/vasomotor centre to respond to blood pressure changes?
Baroreceptors.
Where are baroreceptors found?
- Aortic arch.
- Internal carotid arteries.
Why is the short-term regulation of blood pressure a good example of homeostasis?
Has a feedback loop consisting of:
- receptor.
- controller.
- effector.
What is the receptor, controller and effector in the short-term homeostatic response to blood pressure.
1) . Receptor =
- baroreceptor.
2) . Controller =
- nervous control.
3) . Effector =
- vasomotor tone.
