Control of Cardiac Output and Blood Pressure

Flashcards about the control of cardiac output and blood pressure.

What two factors determine cardiac output?

Stroke volume and heart rate.

What is the average cardiac output at rest?

5L/min.

What is the formula relating Mean Arterial Pressure (MAP), Cardiac Output (CO), and Total Peripheral Resistance (TPR)?

MAP = CO x TPR

Why is it important to regulate blood flow?

To maintain homeostasis by delivering substances and removing waste in response to changing needs.

What is the role of arterioles in the cardiovascular system?

Main resistance vessels that control regional blood flow.

What is the role of venules in the cardiovascular system?

Capacitance vessels.

What is the Frank-Starling mechanism?

Increased venous return leads to increased stroke volume.

How does stretching cardiac muscle affect its contractile force?

Increases contractile force without a change in calcium concentration.

How does dynamic exercise affect venous return?

Increases venous return via muscle and respiratory pumps and active constriction of veins.

What are positive inotropes?

Substances that increase myocardial contractility (e.g., adrenaline, noradrenaline).

What is the effect of positive inotropes on stroke volume?

Increase stroke volume.

What part of the nervous system regulates heart rate?

Autonomic nervous system.

Which branch of the autonomic nervous system increases heart rate?

Sympathetic nervous system.

Which branch of the autonomic nervous system decreases heart rate?

Parasympathetic nervous system.

What is the effect of noradrenaline on the SA node?

Increases heart rate.

What is the main function of the RAAS system?

Regulates plasma volume in the long-term and therefore maintains MAP in the long term

What is the effect of acetylcholine on the SA node?

Decreases heart rate.

What is a positive chronotrope?

Something that increases heart rate.

What is a negative chronotrope?

Something that decreases heart rate.

What physiological changes will increase Cardiac Output?

Increased blood volume, physical activity, sympathetic nervous system activation, or parasympathetic nervous system inhibition.

What stimulus would cause a DECREASE in Cardiac Output?

Decreased blood volume or physical inacAvity

What three factors control blood vessels or Total Peripheral Resistance (TPR)?

Noradrenaline (SNS), Adrenaline, Angiotensin II (RAAS)

The nervous system can regulate resistance by altering .

Radius of arterioles.

The baroreceptor reflex is a -term control of blood pressure.

Short

In the short-term, MAP and pulse pressure changes are detected by what?

Baroreceptors in the carotid sinuses/aortic arch.

In the short-term, where does the integration of the multiple effectors occur?

Medulla of the brain.

Regulation using baroreceptors operates using what mechanism?

NEGATIVE FEEDBACK.

What hormone increases renal sodium reabsorption?

Aldosterone.

What organ releases ANP?

Atria of the heart.

A drop in blood volume will inhibit the release of which atrial hormone?

ANP