7.4 The structure of the heart Flashcards
where is the heart located?
in the thoracic cavity behind the sternum
Describe the general structure of the heart.
- consists of 2 pumps, each with two chambers; an atrium and a ventricle
- between each atrium and ventricle there is a valve which prevents the back flow of bloodinto the atrium when the ventricle contracts
- each chamber is connected to a large vessel which takes blood to/from the heart
Describe the atria and their function.
- thin-walled and elastic, stretch as they collect blood
- receive blood from the veins
Describe the ventricles and their function.
- thick, muscular walls to contract strongly and pump blood out of the heart
- the left ventricle has thicker walls as it has to pump blood all the way around the body at high pressure
- they pump blood away through the arteries
what are the 4 vessels connected to the heart?
- the aorta
- the vena cava
- the pulmonary artery
- the pulmonary vein
describe the aorta
- connected to the left ventricle
- takes oxygenated blood around the body
describe the vena cava.
- connected to the right atrium
- brings deoxygenated blood back to the eart from the body tissues
describe the pulmonary artery.
- connected to the right ventricle
- carries deoxygenated blood away from the heart to the lungs where oxygen is replenished and carbon dioxide is removed
describe the pulmonary vein.
- connected to the left atrium
- brings oxygenated blood to the heart from the lungs.
How is the heart muscle supplied with oxygen?
- it gets its oxygen from the coronary arteries which branch off the aorta
- if these are blocked it leads to a myocardial infarction as an area of the heart will be deprived of oxygen, and the muscle cells will stop respiring and die
Describe the path of blood from the lungs, around the body and back to the lungs.
- pulmonary vein
- left atrium
- left ventricle
- aorta
- vena cava
- right atrium
- right ventricle
- pulmonary artery
