circulatory system-the heart Flashcards
what is a heart?
an organ that pumps blood around the body
what is the heart made of?
muscle tissue
what is the heart’s job?
to pump blood around the body
describe the journey blood goes on from entering the heart.
- deoxygenated enters from body via vena cava into right atrium
- flows into right ventricle then pushed up through the pulmonary artery into the lungs
- gains oxygen in lungs and returns to heart via pulmonary vein
- passes into left atrium, then left ventricle
- oxygenated blood pumped from the heart out to the body through the aorta
what type of system do humans have?
double circulatory
what are the atria separated from the heart by?
valves
which side of the heart has a thicker muscular wall and why?
the left as the left ventricle pumps blood round the whole body at a higher pressure so requires a greater force
describe the pattern of bloodflow
- blood enters the two atria through veins
- the atria contract, pushing the blood into the ventricles and causing the valves to shut
- the ventricles contract, forcing the blood into the arteries and out of the heart
- the blood flows to the organs, then returns through veins and the cycle starts again
what is the purpose of valves?
to prevent the blood from flowing backwards into the atria when the ventricles contract
what do coronary arteries provide?
they provide oxygen from oxygenated blood to the heart’s muscle cells
what is the oxygen used for from coronary arteries?
used in respiration to provide energy for contraction
describe the positioning of coronary arteries
they branch out of the aorta and spread out into the heart muscle
what is a pacemaker?
a group of cells in the right atrium wall that control the resting heartrate
what does a pacemaker do?
control the resting heart rate by producing a small electrical impulse, which spreads to surrounding muscle cells, causing them to contract
when is an artificial pacemaker used?
to control heartbeat if the natural cells don’t work properly
what is an artificial pacemaker?
a small electronic device, implanted under the skin with a wire going to the heart
how does an artificial pacemaker work?
it produces an electrical circuit to keep the heart beating regularly
what is the purpose of the circulatory system?
carries oxygen and other useful substances to tissues and removes waste products
how does a double circulatory system work?
one pathway carries blood from the heart to lungs where gaseous exchange takes place, blood becomes oxygenated
one pathway carries oxygenated blood from the heart to the tissues
what divides the two sides of the heart?
septum
what is the septum?
wall of tissue separating the heart’s left and right side
where does blood pumped by the right ventricle go?
the lungs
where does blood pumped by the left ventricle go?
the body
why is the double circulatory system important?
-makes circulatory system more efficient as oxygenated blood can be pumped around the body at a higher pressure by the left ventricle
-makes it more efficient as the two types of blood aren’t mixing
how many chambers does the heart have and what are they called?
4-right atrium, right ventricle, left atrium, left ventricle
what are the four main blood vessels associated with the heart?
vena cava (right) - carries deoxygenated blood from the body to the heart
pulmonary artery (right) - carries deoxygenated blood from the heart to the lungs
pulmonary vein (left) - carries oxygenated blood from the lungs to the heart
aorta (left) - carries oxygenated blood from the heart to the blood
approx. value of natural resting heart rate
70 bpm
what controls the heart rate?
a group of cells that act as a pacemaker
