Anatomy and physiology

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abi frost

Cards (153)

Define the term cardiac output.  
The volume of blood pumped out from the hearts left ventricles in one minute
What is the equation for cardiac output?
stroke volume x heart rate
Define the term stroke volume. 
the volume of blood pumped out by the left ventricle in each contraction
Define heart rate. 
number of beats per minute
What is meant by the term bradycardia?
resting heart rate below 60 bpm
What is meant by venous return?
the volume of blood returned to the hearts right atrium per min via the veins
Max heart rate 
220 - age
Define cardiac hypertrophy. 
increased cardiac muscle mass
What does starlings law state?
greater stretch leads to the greater the force of contraction, the greater the ejection faction/stroke vol
What is the cardiac conduction system? 
a group of specialised cardiac muscle cells in the walls of the heart that send signals to the heart tissue
Where does the impulse originate from?
sinoatrial node
What is the function of the sinoatrial node?
it initiates the electrical impulse, sending a wave of depolarisation across the atria of the heart, stimulating the atria to contract
What is the name of the node that receives the impulse from the sa node? 
atrioventricular node
What is the function of the av node?
to delay transmission of the impulse to allow time for the atria to fully contract and the ventricles to fill with blood
What is the role of the sympathetic system?
to increase heart rate
What is the role of the parasympathetic system?
to decrease heart rate
Define what is meant by anticipatory rise.
increase in heart rate in anticipation of an event
what is meant by myogenic?
generated within muscle tissue, and can initiate its own impulse leading to contraction.
Define vascular shunting 
blood that can be redistributed to the muscles
What type of receptor detects changes of CO2 in the blood?
chemoreceptor
What type of receptor detects changes in blood pressure?
baroreceptors
What is the role of mechanoreceptors?
to detect changes in movement
What is the role of proprioceptors?  
to detect changes in movement
What is adrenaline? 
a stress hormone that is released by the sympathetic nerves
What is the effect of adrenaline?
increases heart rate
What is meant by the term atherosclerosis?
occurs when arteries narrow and harden due to the build up of fatty deposits
What is atheroma?
a fatty deposit that builds up in artieries
What is angina? 
a chest pain that occurs when blood supply through the coronary arteries to the muscles is restricted.
Define cardiovascular drift. 
where there is decrease in stroke volume and an increase in heart rate to compensate
What type of environment does this occur?
warm environment
What happens to the blood plasma?
due to an increase in temperature, the body sweats losing water meaning the blood plasma becomes less viscous, decreasing stroke volume
Define blood pressure. 
the force exerted on the walls of bloods vessels
Where is the cardiac control centre located?
medulla oblongata
What is meant by the term systolic? 
when the heart is emptying with blood, ventricles are contracting
What is meant by diastole? 
the filly of the heart with blood, ventricles are relaxing
Name the three venous return mechanisms.
pocket valves, skeletal muscle pump and respiratory pump
What is the role of the respiratory pump in venous return?
muscles contract and relax during breathing, pressure changes occur in thoracic and abdominal cavity. these pressure changes compress nearby veins forcing blood back to the heart
What is the role of the skeletal muscle pump in venous return?
When muscles contract and relax they change shape, this shape change squeezes the blood in nearby veins back to the heart.
What is the role of the pocket valves in venous return?
they prevent backflow of blood ensuring blood return to the heart
How is oxygen transported in the blood?
combines with haemoglobin to form oxyhaemoglobin