Human Physio Cardiovascular

The heart

The heart

muscular pump that drives flow of blood to various organs

Blood vessels

conduit through which the blood flows

Blood

carrying materials to and from the cells fluid that circulates around the body

3 layers of the heart wall

Epicardium, myocardium, endocardium

epicardium

connective tissue layer

myocardium

thickest muscle layer (composed of cardiac muscle)

endocardium

endothelium of the heart which also contains Purkinje fibers

Blood comes into the right atrium from the body

Moves into the right ventricle

Pushed into the pulmonary arteries in the lungs.

After picking up oxygen, the blood travels back to the heart through the pulmonary veins into the left atrium

Into to the left ventricle and

Out to the body's tissues through the aorta.

Describe the path of blood flow (start with right atrium)

Cardiac output

________ (CO)= volume of blood pumped by one ventricle per minute.

SA node depolarises

Electrical activity goes rapidly to AV node via internodal pathways

Depolarisation spreads more slowly across atria. Conduction slows through AV node.

Depolarisation moves rapidly through ventricular conducting system to the apex of the heart.

Depolarisation wave spreads upward from the apex.

Electrical conduction pathway in the heart

P wave

atrial depolarisation

QRS complex

Ventricular depolarisation and atrial repolarization

T wave

Ventricular repolarization

Depolarisation

________ moves rapidly through ventricular conducting system to the apex of the heart.

SV (stroke volume)

________ is directly correlated with CO, the greater the ________ the greater the CO.

Pericardium

________- a double serous membrane.

SV

________ represents the difference in the amount of blood between: EDV and ESV.

portal system

two capillary beds connected in series

Pericardium

a double serous membrane

Atrioventricular (AV valves)

between atria & ventricles

Semilunar valves

between ventricles and arteries

Late diastole

both sets of chambers are relaxed and ventricles fill passively

Atrial systole

atrial contraction forces a small amount of additional blood into ventricles

Isovolumic ventricular contraction

first phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves

Ventricular ejection

as ventricular pressure rises and exceeds pressure in the arteries, the smilunar valves open and blood is ejected

Isovolumic ventricular relaxation

as ventricles relax; pressure in ventricles falls, blood flows back into cusps of semilunar valves and snaps them closed

determined by heart rate, stroke volume or both

Cardiac output is....

preload

degree of myocardial stretch before contraction begins

preload

EDV is primarily affected by _____

Preload

______ increases, EDV increases and SV increases

central venous pressure

factor influencing venous return is _____________

EDV

central venous pressure rises, venous return increases, leads to increase in ____

filling time, atrial pressure

preload is affected by ______ and _______

AV valves

between atria and ventricles