the heart Flashcards
what type of blood does the left side of the heart pump and where?
oxygenated blood to rest of body
what type of blood does the right side of the heart pump and where?
deoxygenated blood to lungs
what separates the right and left side of the heart?
the inter-ventricular septum
what do the heart walls contain and what does this mean for blood flow?
muscle and when the muscle contracts the wall flattens and the volume of the chamber decreases
decreasing volume increases pressure so that blood can flow
what do thicker muscle walls enable?
great pressures can be created and transport over greater distances requires greater pressures.
what do veins do? what do arteries do?
veins return blood to heart
arteries carry blood away from heart
what is the largest artery in the blood from the left side of the heart to the rest of the body?
aorta- it has a thick wall to withstand the high pressure that is created by the contraction of the left ventricle
what do valves do?
prevent backflow of blood
what valves are there in the heart and where are these located?
valves between atria and ventricles are atria-ventricular
valves between ventricles and arteries are semi-lunar valves
what does it mean that the heart is myogenic?
it is able to generate its own nerve impulses that stimulate its contraction
what is the area of the heart that first releases nerve impulses and where is this located?
the sino-atrial node (SAN) and it is located at the top of the right atrium
what do the two nerves from the brain that connect to the SAN do?
one causes the SAN to increase the frequency of nerve impulses
one causes the frequency to decrease
this allows heart rate to be sped up or slowed down
where do the nerve impulses from the SAN go?
spread through the atria walls so that both atria contract
the nerve impulses are prevented from travelling through ventricles by non-conducting tissue.
what do nerve impulses from the SAN stimulate?
the atria-ventricular node (AVN) that releases nerve impulses
these travel down the inter-ventricular septum through a collection of fibres called the bundle of His
how do nerve impulses from the AVN get from the Bundle of His to the ventricles?
the Purkinje fibres run through the ventricle walls
nerve impulses travel along them and trigger the ventricles to contract from the bottom upwards
which blood vessel supplies the heart with its own oxygen supply?
coronary arteries
what does a blockage of the coronary arteries lead to?
myocardial infarcation, or heart attack, because an area of the heart muscle is deprived of blood and therefore oxygen
