Cardio Physiology 1 & 2 Flashcards
Blood movement through the heart is gated by?
Valves
This controls the flow between atria and ventricles
AV valves
These control the flow from ventricles out to the circulatory vessels
Aortic and pulmonary valves
Which sides of the heart are the aortic and pulmonary valves? (respectively)
Aortic is on the left
Pulmonary is on the right
Every ______ is activated during heartbeat. Which is different to skeletal muscle because the amount of muscle cells activated can be controlled.
cardiomyocyte
How can we increase the force of cardiac contraction?
By increasing the amount of Ca2+ pumped from SR
More Ca2+ means more crossbridges formed between actin and myosin
More cross-bridges means more contraction
More contraction means more force generated
What are the two circulations in the body?
Systemic circulation and pulmonary circulation
This is characterised by falling blood pressure/relaxation
Diastole
This is characterised by increasing blood pressure/contraction
Systole
What are the five phases of the cardiac cycle?
Atrial Systole, Isovolumetric Interventricular Contraction, Ventricular Ejection/Systole, Isovolumetric Interventricular Relaxation, Passive Filling (of the atria)
True or false. Systole is longer than diastole.
False. Filling of the chambers take up more time, so diastole takes longer.
This is much higher than pulmonary artery pressure.
Systemic arterial pressure.
Why is systemic arterial pressure higher than pulmonary artery pressure?
Because more force is needed to pump blood into the systemic circulation (or arteries in the systemic circulation)
This is the highest point on a blood pressure trace.
Systolic pressure
This is the lowest point on a blood pressure trace.
Diastolic pressure.
This is the difference between the highest and lowest points of pressure.
Pulse pressure
This is the average pressure across the full cycle - so doesn’t necessarily mean the ‘middle’ of the graph.
Mean pressure
This is high blood pressure.
Hypertension
This is low blood pressure.
Hypotension
What is the order of blood pumping in the four chambers of the heart?
So the atrium will pump blood first and then the ventricles.
This is initiated by an increase in cytosolic Ca2+ levels and formation of cross bridges.
Cellular contraction
This is used to determine the systolic and diastolic pressure in the arteries.
Blood pressure trace
These cells are ‘pale’, not really striated appearance and has a low content of actin and myosin
Electrical cells
Purkinje cells and AV nodals are what?
Electrical/conduction cells
There are striated in appearance and has a high content of myosin and actin.
Contractile cells
Action potentials propagate _______ the _______ of electrical and contractile cells.
along; surface membrane
These connect most cells of the heart
Intercalated discs
These are pores with low resistance to ionic current and allow current flow between adjacent cells
Gap junctions
Why is the sinoatrial node known as the pacemaker of the heart?
Because it controls the rate of depolarisation
Depolarisation of the nodes leads to…
Contraction
This allows rapid communication between left and right atria so that both atria will depolarise at the same time, and so contract at the same time.
Interatrial bundle
These are ventricular conducting fibres.
Purkinje fibres
Where does the conduction pathway end?
At the ventricular fibres/Purkinje fibres
Where does the conduction pathway start?
At the Sinoatrial node
When does quiescence end?
When excitation spreads from the SA node.
This is a virtual line between two surface electrodes
Lead
What does a lead do in an ECG?
It detect a difference/changes in the electrical status of the cell.
P wave means what phase?
Atrial depolarisation
QRS wave means what phase?
Atrial repolarisation, ventricular depolarisation
T wave means what phase?
Ventricular repolarisation
Depolarisation and repolarisation are usually recorded by what kind of machine?
An ECG
What wave represents depolarisation of ventricles?
QRS Wave
What wave represents the repolarisation of ventricles?
T wave
What wave represents the depolarisation of the atria?
P wave
Pulsatile changes in pressure in the major arteries is linked to?
Ejection of blood (when blood is ejected the arteries then just pump blood under high pressure)
These are usually in between electrical and contractile cells to allow rapid spread of electrical signals.
Gap junctions
Gap junctions can be in between contractile cells. True or False.
True.
The ______ is responsible for distributing the signals to the ventricular fibres (left and right ventricle)
AV bundles
Where does the conduction pathway end?
Ventricles/Purkinje fibres
Why does the AV node pause the conduction signal?
To allow the atria to repolarise - be fully empty of the blood before contraction in ventricles begins.
