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- Blood vessels
- 5 L of blood
What is transported in the cardiovascular system?
Entering: oxygen, nutrients and water
Within: nutrients, immune cells, chemical messengers
Exiting: metabolic wastes, heat and carbon dioxide
Why have a cardiovascular system?
Diffusion is slow and the area to volume ratio.
have more oxygen than pulmonary arteries
have less oxygen then systemic veins
blood gets oxygenated
Ventricle systole (contraction)
- L/R ventricles contract
- AV valves close (immediately)
- Semilunar valves open (brief delay)
Ventricular Diastole (relaxation)
- L/R ventricles relax
- Semilunar valves close (immediately)
- AV valves open (brief delay)
What happens when AV valves close in systole?
ventricular blood pushes AV valves closed
papillary muscles contract against ventricular wall and chordae tendinae, preventing prolapse of AV valves (opening wrong way)
What happens to semilunar valves when they open during ventricular systole?
Pressurized blood pushes against the aortic and pulmonary valve cusps, opening the valves and ejecting blood out of the ventricles
What happens to the semilunar valves during ventricular diastole?
- Closes immediately.
- Both ventricles relax and blood in ventricle has almost no positive pressure.
- Blood in aorta and pulmonary trunk is still under positive pressure, closing semilunar valves.
What happens to AV valves during Ventricular Diastole?
- Brief delay.
- Blood coming into L/R atria under positive pressure, which opens the AV valves and allows the ventricles to fill
70 mL for resting heart rate
- CNS regulates rate through sympathetic and parasympathetic nervous systems.
- 2 cells contractile (99%) (does the work) and autorhythmic (set the pace)
set the beat for the contractile cells, which actually do the work of the heart