Cardiovascular physiology Flashcards
What is the flow of blood in the body
- From the body to the Vena cava
- Vena cava to the right atrium
- RA to the the RV
- RV to the pulmonary artery
- Pulmonary artery to the lungs
- Lungs to the pulmonary veins
- To the left atrium
- To the left ventricle
- to the aorta
- To the body
Meaning of diastole
Relaxation of the muscle
Meaning of systole
Contraction of the muscle
What is the flow of blood directly proportional to
Change in pressure. So the more blood that flows through a vessel, the higher the pressure.
What is stroke volume
The volume of blood that is pumped by one ventricle
What is cardiac output
Cardiac output is the volume of blood pumped in a minute per ventricle
What is Venus return
The volume of blood returning back to the heart
It should = cardiac output
How do action potentials cause ventricular/ atrial contractions
- AP from adjacent cell causes volume gated CA2+ channels to open
- ca2+ enters
- this causes the sarcoplasmic reticulum to release ca 2+
- the ca2+ binds so troponin causing contraction
- the ca2+ unbinds causing relaxation
- ca2+ is pumped back into the sarcoplasmic reticulum
- ca2+ is exchanged for na+
- na+ concentration is maintained by na+/k+ ATPase
What is the intercalated disk
It’s a disk that holds together numerous cardiomyocytes (singular building block of cardiac muscle) and causes synchronised contractions
In what type of muscle cells are intercalated disks found
Only cardiac muscles
What is the flow of electrical current in the heart
- sinoatrial node
- atrioventricular node
- bundle of his
- purkinje fibres
What is an ECG
Electrocardiography, electrodes are placed on the skin and measure the voltage produced by the heart against time
How is the cardiac output calculated
Stroke volume x heart rate
What determines the heart rate
The rate of depolarisation of autorhythmic cells
What slows down the heart rate
The parasympathetic nervous system