Unit 3 exam Flashcards
4 determinants of cardiac output
- Heart rate
- Preload
- Afterload
- Contractibility
The number of cardiac contractions per minute. Can be affected by many variables depending on pressure.
Heart rate
increases HR by releasing norepinephrine
Positive chronotropic effect
decreases HR by releasing acetylcholine
Negative chronotropi effect
- Directly related to stroke volume.
- The amount of blood in the ventricles at the end of diastole.
- Also refers to the amount of stretch of the muscle tissue at the end of filling.
Preload
- Inversely correlated to stroke volume.
- The resistance to flow the ventricle must overcome to open the semilunar vlalves and eject its contents.
- This is related to bp, vessel lumen diameter and or vessel compliance.
Afterload
A increased after load causes what?
Decreased stroke volume and decreased cardiac output
A decreased afterload causes what?
Increased stroke volume and increased cardiac output
- The force of the mechanical contraction.
- Contractile force can be increased with sympathetic stimulation or calcium release.
- It can be decreased in the face of hypoxia or acidosis
Contractability
What can cause a decrease in contractability
Hypoxia or acidosis
Formula for calculating cardiac output
Heart rate X Stroke volume = Cardiac output
Normal cardiac output in a healthy adult
4-7 L/min
How does exercise or activity affect cardiac output?
Increases it
How does rest/sleep affect cardiac output
Decreases it
Labs associated with CV disease
- Lipid panel
- CPK
- Troponin
- Myoglobin
- BNP
Age related cardiovascular changes
- Atrophy of left ventricle
- Decreased elasticity of aorta
- Valce rigidity
- Stenosis of heart valances
- Stiffening vessels
- Increase fibrotic changes
- Atheroscopic plaques
- Narrowing vessel walls
1 cause of death in older adults
Heart disease
Altherosclerotic plaques cause what? Which increases the risk for what?
- Narrowing of vessel walls
- Increased risk for clots and CVA
Increased fibrotic changes cause what?
HTN
List things that cause alterations in perfusion
- Early menopause
- Clotting disorders
- Congenital cardiac defects
- CAD
- MI
- Dysrhythmias
- Heart failure
- This causes alterations in perfusion.
- This condition causes the circulation of blood to be slowed d/t shifting hormones
Early menopause
- This condition causes alterations in perfusion
- Perfusion is interuppted when it encounters clots or active bleeding
Clotting disorders
- This condition causes alterations in perfusion
- Causes abnormal blood flow through the heart or obstructs blood in the heart or vessels
confenital cardiac deffects
- This condition causes alterations in perfusion
- plaque builds up causing restricted blood flow
CAD