the heart Flashcards
where does aorta take oxygenated blood?
● right side
● head
● left side
● lower body
where does pulmonary artery take deoxygenated blood?
● right lung
● left lung
where does pulmonary vein bring oxygenated blood from?
● right lung
● left lung
where does inferior vena cava bring deoxygenated blood from?
from lower body
where does superior vena cava bring deoxygenated blood from?
from upper body
what is the aorta?
an artery
what is the vena cava?
a vein
what are the 3 parts of the cardiac cycle?
● diastole
● atrial systole
● ventricular systole
what is the atrioventricular valve?
valve in between atrium and ventricle
what is the semi lunar valve?
valve in between ventricle and artery
what happens during a diastole?
● all muscle relaxes
● av valve open
● sl valve closed
● blood flows into the atria
● pressure is highest in the arteries
what happens during an atrial systole?
● atrial muscle contracts
● av valve open
● sl valve closed
● blood flows into ventricle
● pressure highest in atrium
what happens during a ventricular systole?
● ventricular muscle contracts
● av valve closed (prevents back flow of blood into the atria)
● sl valve open
● blood flows into arteries (pulmonary artery, aorta)
● pressure highest in ventricle
explain the structure of the heart
● deoxygenated blood returns from body in vena cava (vein) and enters right atrium
● blood then passes via an atrio-ventricular valve into the right ventricle and, via semi lunar valve, into the pulmonary artery
● blood passes through lungs and returns to left atrium via the pulmonary vein
● blood passes through second atrio-ventricular valve into the left ventricle and then passes through the semi-lunar valve into the aorta where it is pumped around the whole body
why is the left ventricle thicker?
● has thicker, muscular walls than right ventricle
● as it needs to contract powerfully to pump blood around entire body
when do semi-lunar valves open?
when pressure is higher in ventricles than arteries
when do semi-lunar valves close?
● when pressure is higher in arteries than ventricle
● to prevent back flow of blood from arteries to ventricle
when do atrio-ventricular valves close?
● when pressure is higher in ventricle than the atria
● to prevent back flow of blood from ventricle to atria
when do atrio-ventricular valves open?
when pressure is higher in atria than ventricles
what is cardiac output?
volume of blood pumped by left ventricle in 1 minute
what is heart rate?
contraction of heart in a minute
what is stroke volume?
volume of blood that leaves left ventricle per contraction (ventricular systole)
what is the equation for cardiac output?
cardiac output(cm3min-1) = heart rate (bpm) x stroke volume (cm3)
what is CHD?
● coronary heart disease
● a type of CVD
● coronary arteries supply blood to the heart muscle itself
where does CVD occur?
● arteries
● higher blood pressure in arteries more likely to damage endothelium
what are the risk factors of CHD?
● increase in blood pressure - high salt diet (salt lowers water potential of blood plasma, higher pressure damages endothelium)
● increased blood fat levels - high fat level, sedentary lifestyle
● increased heart rate - nicotine / caffeine, leads to a higher blood pressure
what is atherosclerosis?
● the process of atheroma formation
● lumen of artery is narrowed due to build up of fatty deposits and cholesterol underneath endothelium of artery
● deposit is called an atheroma
● plaque forms and bulges into lumen of artery
● atheroma may cause reduced blood flow to heart muscle cells
● if blood vessel is completely blocked, the muscle cells get no oxygen and die
● this will cause a heart attack (myocardial infarction)
what is thrombosis?
● plaque may rupture
● trigger blood clotting over damaged area
● clot builds up very rapidly causing further blockage of artery
● known as a thrombus
● clot may break up, travel up blood stream and cause blockage elsewhere
● could lead to problems such as a stroke
what is an aneurysm?
● when artery blocked - blood flow through area restricted
● blood pressure builds up in front of blockage and presses on artery wall
● pressure causes wall to weaken and it starts to bulge outwards
● known as aneurysm
● vessel may rupture resulting in internal bleeding
