Topic 14 Flashcards
How can cardiac output be calculate?
CO=HR(heart volume) x SV(stroke volume)
What is the cardiac output?
The volume of blood pumped through each
ventricle per minute is the cardiac output
What is the function of atrial systole?
Atrial systoleransfers the remainder of the blood through
the atrio-ventricular (AV) valves to the ventricles.
What is the function of ventricular systole?
Ventricular systole closes the AV valves and pumps the blood out through the semi lunar (SL) valves to the aorta and pulmonary artery
What valve is open during atrial systole?
AV valve
What valve is open during ventricular systole?
SL valve
What is the function of atrial and ventricular diastole?
In diastole the higher pressure in the arteries closes the SL valves
What part(s) of the heart are responsible for the noise heard with a stethoscope?
The opening and closing of the AV and SL valves are responsible for the heart sounds heard with a stethoscope.
What structure in the heart sets the rate at which cardiac muscle cells contract?
The auto-rhythmic cells of
the sino-atrial node (SAN)
What is the timing of cardiac cells contracting controlled by?
the impulse from the SAN spreading through the atria and
then travelling to the atrio-ventricular node (AVN) and then through the ventricles.
Where is the SAN located?
the wall of the right atrium.
Where is the AVN located?
the junction between the atria and the ventricles.
What device can be used to detect the impulses from the SAN?
These impulses generate currents that can be detected by an electrocardiogram (ECG)
What nerves and what hormone speed up the heart?
Sympathetic accelerator nerves release noradrenaline
nor-epinephrine
What nerves and what hormone slow down the heart?
slowing parasympathetic nerves release acetylcholine.
