The Heart Flashcards
What is the main role of the heart?
To pump blood.
Describe the hearts structure.
It is a cone shaped hollow muscular organ, the size of the owners clenched fist.
Where is the heart located?
In the middle of the thoracic cavity.
Under the sternum.
Between the lungs.
Above the diaphragm.
What membrane surrounds the heart?
The pericardium.
What is the role of the pericardium?
It is a membrane that surrounds the heart and prevents friction with nearby organs when the heart contracts.
What muscle is the wall of the heart made of?
Cardiac muscle.
What are the features of cardiac muscle.
It is involuntary.
It contracts strongly- it can shorten.
It does not tire.
Describe the hearts blood supply.
As a living organ of the body, the heart has its own blood supply through the coronary arteries and the cardiac veins.
What is the role of the coronary arteries?
They deliver oxygenated blood to the cardiac muscle wall of the heart.
Where do coronary arteries arise?
From the base of the aorta just beyond the semilunar valve.
What is the role of the cardiac veins?
They drain deoxygenated blood from the cardiac muscle wall of the heart directly to the right atrium.
Distinguish between oxygenated and deoxygenated blood.
Oxygenated blood is high in O2 and low in CO2.
Deoxygenated blood is high in CO2 and low in O2.
What is the region of lowest pressure in the heart and why?
The right atrium as pressure decreases as the right atrium receives blood against the force of gravity from the longer systemic circuit.
What is the region of highest pressure in the heart and why?
The left ventricle is the region of highest pressure as it must pump blood out into the aorta and through the longer systemic circuit.
Why is the wall of the left ventricle thicker?
To pump blood out into the aorta and through the longer systemic circuit.
Describe the structure of the atria.
They are the thin walled upper chambers.
They only pump blood the short but equal distance to the ventricles.
What are the functions of the atria?
They receive blood from the veins and pump it a short distance down to the ventricles.
Describe the structure of the ventricles.
They are the thicker walled lower chambers.
They pump blood through the longer systemic circuit.
What are the functions of the ventricles?
They pump the blood out of the heart into the arteries.
Describe the structure of the septum.
Middle cardiac muscular wall.
What are the functions of the septum?
Keeps oxygenated and deoxygenated blood separate.
Describe the structure of the tricuspid valve.
Has 3 flaps.
What are the functions of the tricuspid valve?
Prevents the backflow of the blood from the right ventricle to the right atrium.
Describe the structure of the bicuspid valve.
Has 2 flaps.