Lecture 8: THE HEART AS A PUMP Flashcards
How is the heart in the mammalian cardiovascular system?
Four chambered (atria and ventricle on each side)
How does the blood flow in the mammalian cardiovascular system?
In one direction
Where does arterial blood flow?
Away from the heart (not always oxygenated)
Where does venous blood flow?
Towards the heart (not always deoxygenated)
The heart is …
Two pumps that lie in series
What is the first part of the heart series?
Right atrium
What comes after the right atrium?
Right ventricle
What comes after the right ventricle?
Lungs
What comes after the lungs?
Left atrium
What comes after the left atrium?
Left ventricle
What comes after the left ventricle?
All organs
What goes through the two circuits?
Equal flow
What happens when the atria contract?
AV valves are open to allow the ventricle to fill while the semilunar valves are closed so that pressure builds up in the ventricles
What happens when the ventricles contract?
AV valves close so as the ventricles contract it puts force on the blood and makes sure the blood doesn’t flow backwards.
What happens when pressure gets great enough?
The semilunar valves open and ejection of the blood occurs
What contracts simultaneously?
Right and left pumps
What contracts first?
Atria
What contracts second?
Ventricles
What do valves do?
Open and close to direct blood
What is the thin filament?
Actin (light coloured)
What is the thick filament?
Myosin (blue coloured)
How are calcium levels during relaxation?
Low