The cardiovascular system: The heart Flashcards
What is the pericardium?
Membrane surrounding and protecting the heart. It confines while still allowing free movement.
What are the four layers of the heart wall?
The pericardium, eoicardium, myocartium and endocardium.
Which are the four heart chamber?
Right and left atrium and right and left ventricle.
What do the two atrias do?
They receive blood from veins.
What do the two ventricles do?
They pump blood into arteries.
What function do heart valves have?
They insure one-way flow in the heart and open and close do to pressure changes as the heart contracts and relaxes.
What is the systemic circuit?
It’s in the left side of the heart and receives blood from the lungs.
What is the pulmonary circuit?
It’s on the right side of the heart and receives blood from systemic circulation.
What is the cardiac cycle?
All events associated with one heartbeat.
What is cardiac output?
CO = volume of blood ejected from left (or right) ventricle into aorta (or pulmonary trunk) each minute.
What three factors effect stroke volume?
Preload–Contractility–Afterload.
What is preload?
Degree of stretch on the heart before it contracts (Greater preload increases the force of contraction).
What is contractility?
Strength of contraction at any given preload.
What is afterload?
Pressure that must be overcome before a semilunar valve can open.
