The Heart Flashcards
What is the function of the heart?
The heart is an extremely important muscular organ which pumps oxygenated blood around the body, and deoxygenated blood to the lungs where it can be oxygenated again.
What arteries are part of the heart?
The aorta and pulmonary artery
What veins are part of the heart?
The vena cava and the pulmonary vein.
What is a double circulatory system?
Blood flows through the heart and body twice
Why does the left ventricle have a thicker muscular wall than the right ventricle?
The blood is at a higher pressure in the left ventricle which needs to be maintained to be pushed out and flow around the whole body adequately, whereas the right ventricle is only pumping blood to the lungs.
Why are valves necessary?
They prevent the backflow of blood
What does the Vena cava do?
The superior vena cava brings in deoxygenated blood from the head and upper body parts, the inferior vena cava brings in deoxygenated blood from the lower parts of the body.
from here the deoxygenated blood is pumped into the right ventricle via the bicuspid valve.
What does the pulmonary artery do?
Deoxygenated blood pumped from the right ventricle is pushed out of the pulmonary vein where it is taken to the lungs to be oxygenated and later return back to the heart via the pulmonary vein.
What does the pulmonary vein do?
Oxygenated blood that comes from the lungs is pumped back into the heart through the pulmonary vein into the left atrium where it is pushed back out of the aorta.
What does the aorta do?
Oxygenated blood is pushed from the left ventricle into the aorta where it is pushed out to the rest of the body.
What is the coronary artery?
A large artery which supplies the heart muscle with oxygen and nutrients
How is the heart myogenic?
The heart does not require an external signal to beat, the beat is initiated from the heart itself.
What is the sino-atrial node / SAN / pacemaker?
The cells in the SAN become depolarised (electrically excited) which triggers a wave of electrical excitation to spread across the atria, causing contraction.
(Atrial systole)
What is the atrio-ventricular node / AVN?
The AVN transmits the electrical signal from the SAN to the ventricles
What is depolarisation?
The cells of the heart become less negative and contract
