intro to cardiovascular system Flashcards
function of the cardiovascular system
function of the cardiovascular system
transfer of oxygen and carbon dioxide
transfer of nutrients
transfer of hormones
transfer of heat
why is the cardiovascular system very reliable
this is because the pump can vary output
the vessels can redirect blood
vessels can store blood
arrangement of the pumps
arranged in series in order for the output to be equal to the input
arrangement of the vascular beds
arranged in parallel so that all tissues can get oxygenated blood and this allows redirection of blood.
what is the flow of blood
blood flow is the pressure gradient /resistance
relationship between flow and pressure
flow is directly proportional to pressure and inversely proportional to resistance
function of arterioles
they are taps that control resistance to each of the vascular bed
regional redirection of blood flow
occurs in the arteries
function of veins
storage of blood ; there is blood pooling in the veins 2/3 of the blood
control of fractional distribution of blood
veins
control of regional distribution if blood
arteries
structure of an artery
muscular
wide lumen
strong thick and non elastic wall
low resistance conduit
Septum
Separates the left and the right side
Mitral valve
Located between the atrium and the ventricle of the left side
Tricuspid valve
Located between the atrium and the ventricle of the right hand side
Papillary muscle
Holds the atrioventricular valves and prevents regurgitation
Aortic valve
Valve at the bottom of the aorta
Pulmonary valve
Valve at the bottom of the pulmonary artery
Pulmonary trunk
Pulmonary artery
What causes contraction in the myocytes of the heart
Influx of calcium ions
Is there tetanus in cardiac muscle cells
No ;this is to enable the cells to relax so there is filling up of the heart
Intercalated discs
Electrically connected via the gap junctions
Physically connected via desmosomes
Action potential in a cardiac muscle
Longer than action potential in normal muscle cells
Pacemaker cells
They have unstable membrane potential
This means they do not need a stimulus to generate the action potential
Action potential of a non pacemaker
Entry of sodium ions into the cell upto a certain positive membrane potential
Permeability of sodium ions reduces
Permeability of potassium ions decreases while the permeability of calcium ions increases This is at the plateau phase .
The permeability of potassium ions increases while calcium ions decreases
Resting membrane potential of the non pacemaker action potential
There is permeability of potassium ions
Pacemaker pre potential
Very unstable Andean it is controlled by the funny ion channels which enables the cells to reach the threshold for shooting of an action potential allow the sodium ions and a decrease in the potassium levels as well as the late increase in calcium ions
how is the action potential of the pacemaker cells generated
The funny ion channels close ; tiny calcium ion channels at the start ;at the end there are more L -type calcium ions that open
Action potential of the pacemaker cells
Increas in calcium ions to the most. Positive threshold ;before the calcium ions close and there is increased in the permeability of potassium ions until it reaches negative
Sinoatrial node
Pacemaker that releases the signals
Atrioventricular node
Delaying the spread of the electrical signals which is to enable the atrium to contract before spreading in wave
Bundle his and purkinje fibres
There is rapid conduction of electrical signals
Atrial excitation
Sinoatrial node releases. The signal waves to the AVN. ,the atrium contracts
Atrial fibrillation
There is loss of the p wave
Ventricular fibrillation
There is loss of the qrs complex
Systolic pressure
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