The heart (8) Flashcards
What muscle is the heart made of
Cardiac muscle
What separates the right from the left side of the heart
Septum
What produces the pumping movement of the heart
The regular contraction and relaxation of the cardiac muscles
What are the atrio ventricular valves for
The valves separate the ventricles from the atrium
Which valve is on the left (often known as the mitral valve)
The biscupid valve
Which valve is on the right
The tricuspid valve
When do the valves shut and why
When the ventricles contract, so blood cant flow back into the atria
What blood vessels can be seen on the outside of the heart and what do they do
The coronary arteries, they deliver oxygenated blood to the heart walls.
Why are there coronary arteries on the outside of the heart
Cos the heart is so thick (especially around the left ventricle) the muscle on the outside of the heart is too far away from the blood inside the ventricles to obtain o2 from it.
What is a myocardial infection
A heart attack
Why are the atria walls very thin
Theres no need to generate high pressure blood as the blood doesnt need to be pumped far.
Why do the left ventricle walls need to be thicker than the right ventricle wall
The left ventricle needs to pump blood around the body against greater resistance so high pressure blood needed
Why must the blood from the left side of the heart be separate from the blood on the right side of the heart
To not mix the oxygenated blood (left) with the deoxygenated blood (right). If they were to mix the transport of o2 would be less efficient.
Why is it important that the blood pressure is highest in the heart compared to anywhere else in the circulatory system.
To ensure mass flow. Blood will flow from high pressure to low pressure
What exactly is a hole in the heart
It is a gap in the septum. Before birth the septum isn’t fully developed. After birth it closes, sometimes they dont fully close.the bigger holes can lead to severe health problems.
What is the gap in the septum called
The foremen ovale
With a large hole in the heart what happens
The deoxygenated and oxygenated blood mixes, so blood does not carry enough o2 to tissues
What is the role of the tendinous cords in the ventricles
They prevent the AV valves from being turned inside out.
The 3 parts to the cardiac cycle
Diastole (relaxation).
Atrial Systole (contraction). Ventricular Systole (contraction).
What happens in diastole
relaxation
What happens in atrial systole
the pressure in the atria rises higher than that in the ventricles, so the valves are pushed downwards by the higher pressure of the blood in the atria.
What happens in ventricular systole
the pressure in the ventricles rose above that of the atria, so the valves are being pushed upwards. they cant flap past their opening as they are anchored by the heart tendons holding them to the heart wall. (pressure in the ventricles rise much higher than in the atria as it has much thicker walls)