cardiovascular system design Flashcards
what are the 5 main functions of the cardiovascular system?
- contractions of individual cardiac cells must occur at regular intervals and be synchronized
- valves must fully open
- valves must not leak
- muscle contractions must be forceful
- ventricles must fill adequately durning diastole
about how many liters are there in the interstitial compartment (internal environment)?
12 L
about how many liters are there in the intracellular compartment?
30 L
about how many liters are there in the circulating plasma compartment?
3 L
out of the kidney, skeletal muscle, liver/GI tract, brain and heart which organ has the highest VO2 (O2 consumption as a percentage)
skeletal muscle (about 27%)
out of the kidney, skeletal muscle, liver/GI tract, brain, skin and heart which organ has the lowest VO2 (O2 consumption as a percentage)
kidney (about 7%)
at any point in time, what percentage of blood is systemic circulation?
~84%
remainder in hear (~7%) and pulmonary vessels (~9%)
where does the right ventricle pump blood into?
pulmonary circulation
how does re-oxygenated blood return to the L. atrium
pulmonary veins
what two valves regulate the entry of blood into systemic circulation?
mitral and aortic valves
what two valves regulate the entry of blood into pulmonary circulation?
tricuspid and pulmonary valves
define cardiac output
quantity of blood per unit time pumped into the aorta by the heart
SV x HR
what is the typical cardiac output for a resting individual?
5 L/min
what are the 3 major determinants of stroke volume?
- ventricular preload
- ventricular afterload
- myocardial contractility
list 3 factors that can decrease CO
- siting or standing from lying position
- rapid arrhythmia
- heart disease
list 5 factors that can increase CO
- anxiety and excitement
- eating
- exercise
- high environmental temp
- pregnancy
- epi
what does starling’s law state
stroke volume increases as end diastole volume increases (other things being constant)
define mean arterial pressure
the average pressure over the entire cardiac cycle. It is estimated from diastolic pressure and pulse pressure
MAP= CO x TPR
define pulse pressure
it is the difference between the systolic and diastolic pressure
define systolic pressure
peak pressure reached during blood ejection from the heart
define diastolic pressure
lowest pressure point during which the heart is filling with blood
what is the dichrotic notch
it is the small dip caused by the backfilling of the aortic valve as it closes
where is the circulatory system is blood pressure the lowest? the highest?
the lowest: pulmonary veins
highest: large arteries
is taking BP via the ausculatory method considered direct or indirect?
indirect
how do you measure pulmonary venous and left arterial pressures?
need to use pulmonary capillary wedge pressure
what is the average pulse pressure in a resting adult?
40 mmHG
give two equations to calculate pulse pressure
PP= SD-DP PP= SV/compliance
in the short term, how is MAP controlled? how is this accomplished?
by altering peripheral resistance and cardiac output
this is accomplished neurally and hormonally
how is long term control of MAP achieved?
primarily by altering blood volume via the kidneys
what is the units for human blood pressure?
mercury (because we calculate BP in regards the environmental pressure)
