The Heart and Cardiac Cycle Flashcards
Describe the walls if the atria.
Thin walled, elasticated, and stretch when they fill with blood.
Describe the walls of the left ventricle.
Slightly thicker with more muscle so blood can be forced out of the heart to the rest of the body or lungs.
What do valves do?
Prevent the backflow of blood back into the heart.
What does the aorta do?
Carries oxygenated blood away from the heart towards the body.
What does the vena cava do?
Carries deoxygenated blood back to the heart from the rest of the body.
What does the pulmonary artery do?
Carries deoxygenated blood from the heart to the lungs.
What does the pulmonary vein do?
Carries oxygenated blood from the lungs back to the heart.
Where are the AV valves found?
Between the atria and ventricles.
Where are semi lunar valves found?
Pulmonary artery
Aorta
Why does the left ventricle have the most cardiac muscle?
To ensure the heart can withstand the high pressures needed to force blood out of the heart.
Describe characteristics of the cardiac muscle.
Lots of myoglobin
Lots of mitochondria to release ATP for muscle contraction
Contracts involuntarily.
Describe the human circulatory system.
Double.
The first circulatory system carries blood from the heart around the body.
The second circulatory system carries deoxygenated blood from the heart to the lungs.
How does the heart receive a supply of oxygen?
Coronary arteries surround the heart to supply it with oxygen.
What happens if the corornary arteries become blocked?
Blockages will prevent the heart from receiving a sufficient supply of oxygen, leading to heart attacks.
What is a cardiac cycle?
A sequence of events that occurs within 1 heartbeat.
What is diastole?
Relaxation of the heart.
In diastole, what happens to pressure when the atria fill?
When do AV valves open and why?
Where does blood move from/to?
Pressure increases in the atria.
AV valves open once pressure in the atria is higher than in ventricles, so the ventricles fill.
During diastole, what happens to ventricle walls and how does this change pressure?
Pressure in the ventricles is now _______ compared to which 2 vessels?
Which valves close next?
Ventricle walls relax. This causes them to recoil, reducing the pressure.
Pressure in the ventricles is now lower than in the aorta and pulmonary artery.
The semi lunar valves in the pulmonary artery and aorta shut.
What is atrial systole?
Contraction of the atria.
During atrial systole, which part of the heart contracts now?
Atrial walls.
In atrial systole, what do the ventricle walls do?
They relax and recoil.
In atrial systole, where does blood move from/to?
Which valves remain closed?
Any remaining blood from the atria is forced into the ventricle.
Semi lunar valves stay shut.
What is ventricular systole?
Contraction of the ventricles.
In ventricular systole, what happens to the ventricle walls as they fill with blood?
Ventricle walls contract.
