the heart Flashcards
what are coronary arteries
they cover the surface of heart supplying heart with oxygenated blood
what does the septum do
muscle which separates ventricles and oxygenated and deoxygenated blood
why does the left ventricle have a thicker muscle
as blood is travelling to the body so a higher pressure must be created
what is the initiation of a heart beat
-wave of excitation is released from the SA node
-the wave spreads across the atria
-atrial walls contract
-waves of excitation reaches AV node
-Wave spreads down the septum along the bundle of His to the purkinje fibres
-ventricles contract pushing blood up and out of the heart
what are atrio-ventricular valves
valves between the atrium and ventricles
tricuspid and bicuspid
what side of the heart pumps deoxygenated blood to the lungs
right side
what side of the heart pumps oxygenated blood to the body
left side
what do tendinous cords do
attached to the valves and prevents them from turning inside out when the ventricle walls contract
what is systole
contraction of the heart muscle
what is diastole
relaxation of the heart muscle
what is an ECG trace
monitors the electrical activity of the heart
what is bradycardia
slow heart rhythm
what is ectopic heartbeat
an extra beat or an early beat of the ventricles
what is fibrillation
uncoordinated contraction of atria and ventricles
what is trachycardia
rapid heart rhythm
why is it important for the atria and ventricles to be in coordination
causes fibrillation which causes an inefficient pumping
what does the P wave show on an ECG
shows the excitation of the atria
what does the QRS waves show on a ECG
indicates the excitation of ventricles
what does the T wave show on an ECG
shows diastole
properties of the atria
-thin walls as does not need to contract
-elastic walls to stretch when blood enters
properties of left ventricles
-thick walls to enable contraction
-this creates higher blood pressure to enable blood to flow longer distances (to lungs and the rest of the body)
properties of the right ventricle
-pumps blood to the lungs
-blood needs to be at lower pressure to prevent damage to capillaries in the lungs and to allow time for gas exchange to happen
what are the two veins in the heart
pulmonary vein and the vena cava
what does the vena cava do
transports deoxygenated blood from the body to the right atrium
what does the pulmonary vein do
carries oxygenated blood from the lungs to the left atrium
what are the two arteries in the heart
pulmonary artery and aorta
what does the pulmonary artery do
carries deoxygenated blood from the right ventricle to the lungs
what does the aorta do
carries oxygenated blood from the left ventricle to the body
when do valves open and close
opens when pressure is higher behind the valve
closes when the pressure is higher in front of the valve
what happens in diastole
-ventricles and atria are both relaxed
-The pressure in the ventricles drops below the aorta and pulmonary artery, forcing the SL valves to close
-The atria continues to fill with blood
-Blood returns to the heart via the vena cava and pulmonary vein
-Pressure in the atria rises above that in the ventricles, forcing the AV valves open
-Blood flows passively into the ventricles without need of atrial systole
when are the atrioventricular valves open and closed
open- atrial systole and diastole
closed- ventricular systole
when are the semi-lunar valves open and closed
open- ventricular systole
closed- atrial systole and diastole
