Cardiac Output And Regulation Of Cardiac Function Flashcards
Define cardiac output
Quantity of blood pumped by the heart in a given period of time
Define stroke volume
The volume of blood pumped out of the LV during each heart contraction
Define heart rate
The speed at which the heart beats
What stimulates the renin-angiotensin-aldosterone system?
-fall in blood vol.
OR
-renal blood flow
What’s the difference between intrinsic and extrinsic control?
Controlled by internal factors/hormones or external stimuli
What is starlings law of the heart?
How’s this achieved?
Rate of blood out of the heart, is automatically adjusted to match the rate of blood going into the heart
= stretch of cardiac myocytes
What’s pre-load and after-load?
Pre-load = the initial stretching of the cardiac myocytes prior to contraction
After-load = amount of resistance heart must overcome to open the aortic valve and push blood out
How does pre-load and after-load affect stroke volume?
- increase in after-load = decrease in stroke volume
What are the 3 factors that can affect stroke volume?
- Ventricular contractility
- End-diastolic volume
- Afterload
What’s meant by ventricular contractility?
- force of ventricular contraction
What is orthostasis?
The fact that standing up right can beg a challenge for the CV system
- gravity prevents distribution of blood
- additional energy needed to get blood to brain
What’s the purpose of cardiopulmonary stretch receptors?
Regulate blood volume
What type of cell detects the fall in blood flow/renal blood flow in the renin-angiotensin-aldosterone system and where is it located in the body?
Juxtaglomerular cells in the kidney
What enzyme do juxtaglomerular cells release?
+ what does this cause
Renin
1. causes vasoconstriction
2. increase secretion of aldosterone
3. aldosterone increases sodium&water retention
4. Increase blood flow
