Cardiac Structure And Function Flashcards
What is contained in the heart wall
1.epicardium
2.myocardrium
3.endocardium
Epicardium characteristics and function
- Serous membrane including blood capillaries, lymph capillaries and nerve fibres
- Serves as lubricating outer covering
Myocardium characteristics and function
- Cardiac muscle tissue separated by connective tissues and including blood capillaries lymph capillaries and nerve fibres
- Provides muscular contractions that eject blood from the heart chambers
Endocarium characteristics and function
- Endothelial tissue and a thick sub endothelial layer of elastic collagenous fibres
2.serves as protective inner lining of the chambers and valves
What is the SA node
Pace maker, initiates depolarisation
What is the AV node
Passes depolarisation to ventricles, brief delay to allow ventricles to fill
What do bundle branches do
Connect atria to left and right ventricle
What do the purkinje fibres do
Spread wave of depolarisation throughout ventricles
Conduction system of the heart REMEMBER IT
What is atherosclerosis
- Fatty plaque that narrows coronary arteries
2.reduces blood flow to myocardium
How Exercise reduces the amount of myocardial damage from heart attack :
1.improvements in heart’s antioxidant capacity
2. Improved function of atp sensitive potassium channels
What is the parasympathetic nervous system
1.Via the vagus nerve
2. Slows heart rate by inhibiting SA AND AV node
What is the sympathetic nervous system
1.Increases heart rate by stimulating SA AND AV node
2.Via cardiac
Control of the coronary circulation mechanical forces:
At rest 80% of flow takes place during diastole, during heavy exercise 40-50% occurs during systole
What can ecg trace detect
Abnormalities in hearts electrical activity, evaluating hearts response to increased workload.
