7.4- THE STRUCTURE OF THE HEART Flashcards
What is the heart?
muscular organ that lies in the thoracic cavity behind the sternum (breastbone)
How long does the heart operate?
operates continuously + tirelessly throughout life of organism
What is the human heart really?
two separate pumps lying side by side
What does the left pump of the heart deal with?
oxygenated blood from lungs
What does the right side of the heart deal with?
deoxygenated blood from body
What are the names of the two chambers that each pump of the heart has?
atrium
ventricle
What is the atrium?
thin-walled + elastic + stretches as it collects blood
What is the ventricle?
thick muscular wall as it has to contract strongly to pump blood some distance, either to lungs or rest of body
Why does blood have to pass through tiny capillaries in the lungs?
to present a large SA for exchange of gases
What does blood having to pass through tiny capillaries in the lungs cause?
very large drop in pressure + so blood flow to rest of body would be very slow
What do mammals have as the blood pressure drops due to blood passing through tiny capillaries in the lungs?
mammals have system in which blood returned to rest of body
What is it essential to separate in the heart?
essential to keep oxygenated blood in pump on left side separate from deoxygenated in pump on right
Where does the right ventricle only pump blood to
pumps bloody only to lungs
What is the muscular wall of the right ventricle like in comparison to the left ventricle?
thinner muscular wall than left ventricle
Why does the left ventricle have a thick muscular wall?
enables it to contract to create enough pressure to pump blood to rest of body
How do both the pumps of the heart pump? (hint-time)
pump in time with each other
How do both the atria and ventricle contract?
both atria contract together + then both ventricles contract together, pumping same volume of blood
What is between each atrium + ventricle?
valves
What do the valves between each atrium + ventricle do?
prevent backflow of blood into atria when ventricles contract
What are the two valves
left atrioventricular (bicuspid) valve right atrioventricular (tricuspid) valve
What is each of the four chambers of the heart connected to?
large blood vessels that carry blood towards or away from heart
Where do the ventricles pump blood to?
pump blood away from heart + into arteries
Where do the atria receive blood from?
receive blood from veins
What are pulmonary vessels?
vessels connecting the heart to the lungs
What is the aorta connected to?
connected to left ventricle
What does the aorta carry?
carries deoxygenated blood to all parts of body except lungs
What is the vena cava connected to?
right atrium
What does the vena cava bring?
brings deoxygenated blood back from tissues of body (except lungs)
What is the pulmonary artery connected to?
right ventricle
What does the pulmonary artery carry?
deoxygenated blood to lungs, where its oxygen replenished + its CO2 removed
Unusually for an artery. what type of blood does the pulmonary artery carry?
carries deoxygenated blood
Is the oxygenated blood passing through the left side of the heart used to meet its own great respiratory needs?
no
Which blood vessels supply blood to the heart muscle?
coronary arteries
Where do the coronary arteries branch off?
branch off aorta shortly after it leaves the heart
Example of how the coronary arteries can be blocked?
by blood clot
What do blockages of the coronary arteries lead to?
myocardial infarction or heart attack as an area of heart muscle deprived of blood + so oxygen also
What happens to area of heart deprived of blood?
muscle cells in this region unable to respire (aerobically) + so die
