The Structure of the Heart Flashcards
What are the atrio-ventricular valves?
Valves between the atria and the ventricles, which ensure that blood flows in the correct direction
What is cardiac muscle?
Specialised muscle found in the walls of the heart chambers
What are the semilunar valves?
Valves that prevent blood re-entering the heart from the arteries.
Where is the heart found in humans?
Just off-centre towards the left of the chest cavity.
Describe the characteristics of cardiac muscle.
Firm and dark-red muscle
There are four chambers in the heart. What are they?
Right and left ventricle.
Right and left atria.
What is the name of the arteries which lie on top of the heart?
Coronary arteries
What do the coronary arteries do?
Supply the heart muscle with oxygenated blood.
Reduction in blood flow to the heart muscle could result in what?
Angina or a myocardial infarction (heart attack).
Describe the flow of de-oxygenated blood through the heart starting at the inferior and superior vena cava.
Blood flows through the vena cava into the right atrium.
Through the atrio-ventricular valve into the right ventricle. Out of the semilunar valve into the pulmonary artery to the lungs.
What do the tendinous cords do and where are they found?
They are found at the valves and the prevent the valves from turning inside out when the ventricle walls contract.
What does the septum do?
Separates the de-oxygenated and oxygenated blood.
Describe the thickness of the muscle walls of the four chambers and why they are like that.
Atria have thin walls as they only need to pump blood down into the ventricles.
Left ventricle has very thick walls. Often 2/3 times thicker than the right ventricle as it has to pump blood into the systemic circuit around the entire body.
Right ventricle ahs thick walls as it needs to pump blood around the pulmonary circuit.
Why can the blood pressure coming form the right ventricle not be too high?
The alveoli are very delicate and could be damaged by very high blood pressure.
Cardiac muscle fibres branch. Why is this beneficial to the heart?
It spreads the stimulus around the heart.
Ensures that the muscle produces a squeezing action rather than a simple reduction in length.
