Week 7 - Hemodynamics Flashcards
1
Q
What is homeostasis? (6)
A
- stability of systems that maintain life
- includes pH
- concentration of different ions in the ECF (Na, Ca)
- osmolality of ECF
- glucose levels
- artificial oxygen tension
2
Q
What is allostasis? (7)
A
- adaptation to changing external and internal environment
- includes: Arterial blood pressure
- HR
- body core temperature
- concentration of circulating hormones
- sleep-wake cycle
- energy metabolism
3
Q
Pathophysiology map
A
4
Q
What occurs in systemic circulation? (2)
A
- arteries supply tissues of the body with nutrient and oxygen-rich blood
- veins return blood to pulmonary circulation
5
Q
Which route does blood take in systemic circulation? (3)
A
- LA/LV to aorta
- aorta to body
- Body back to RA/RV
6
Q
What is the route for pulmonary circulation? (3)
A
- RA/RV pulmonary artery to lungs
- pulmonary veins to LA/LV
- reoxygenated and returned to systemic circulation
6
Q
Hemodynamics diagram
A
6
Q
What is the formula for cardiac output?
A
CO = HR(SV)
7
Q
What is cardiac preload? (3)
A
- volume of blood returned to the heart pre-systole
- exerts pressure on the ventricle walls
- also described as the filling force applied to the heart
8
Q
What is Franl-Starling’s mechanism, as it applies to cardiac preload?
A
- When the heart stretches, it generates more force to effectively pump the increased load
note that it has limits
9
Q
Is cardiac preload oxygen efficient?
A
- increased preload increases the oxygen demand of the myocardium, but is more oxygen efficient that increasing the heart rate
10
Q
What is cardiac afterload?
A
- the pressure the ventricle must overcome to eject blood into the arteries
11
Q
What mechanism occurs in cardiac afterload? (2)
A
- during contraction, the left ventricle must generate more pressure than the aortic diastolic pressure
- the pressure must be great enough to overcome the peripheral resistance
12
Q
What is a benefit of reducing afterload?
A
reducing the afterload with vasodilators is a useful therapy for a failing heart
13
Q
What is a risk of increased afterload?
A
- can decrease stroke volume
