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Flashcards in Cardiac output Deck (15)
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1
Q

What is cardiac output

A

volume of blood pumped by each ventricle per minute.

2
Q

What can effect cardiac output

A

heat loss, digestion, and localised vasodilation.

3
Q

How is stroke volume controlled

A

modified and controlled by
Pre load
contractility
afterload

4
Q

Define preload

A

starlings law of the heart. End diastolic volume.

Preload is directly proportional to the force of contraction during systole.

5
Q

What are two factors that control the end diastolic volume

A

Duration of ventricular diastole

Volume of blood entering the right ventricle.

6
Q

Define contractility

A

Contracitity of cardiac muscle increased by positive inotropic agents and decreased by negative inotropic agents.

7
Q

What are examples of positive inotropic agents.

A

Neurotransmitters and hormones of the sympathetic nervous system,

8
Q

Give examples of negative inotropic agents

A

parasympathetic neurotransmitters, calcium channel blockers.

9
Q

Define afterlaod

A

pressures in the aorta and the pulmonary trunk that needs to be overcome by systole

If after load increases then the preload is constant, then the stroke volume will decrease and more blood will remain In the ventricles.

Afterrload can increases because of narrowing of the arteries and hypertension.

10
Q

What controls the heart rate and where can this be found

A

Controlled by cardiovascular centre located in the medulla oblongata

11
Q

What receptors does the heart receive afferent information

A

Sensory receptro.

12
Q

What factored can affect heart rate

A

Age
gender
physical fitness body temperature

13
Q

What is congested heart failure

A

Describes a heart failing to pump.
Associated with valve defects, septal defects

Heart is overstretched and strarts to contract less forcefully

14
Q

What is left ventricular failure

A

Blood to back up backing the lungs causing an increase in venue pressure and a build up of fluid in the lungs.

15
Q

What is right ventricular failure

A

Blood bak sup into systemic system.

decreased volume of blood returning to the left atrium via the pulmonary vein.

can cause decreased blood flow to the kidneys resulting in activation of the rennin angiotensin aldosterone system which increases the kidneys reuptake of water.