Cardiovascular Compensation Flashcards
What are ganglia?
Clusters of nerve cells in the autonomic nervous system
What is the thoracolumbar nervous system also known as?
The sympathetic nervous system
What is the craniosacral nervous system also known as?
The parasympathetic nervous system
Where is the sympathetic nervous system anatomically? What does this system require?
Out of the thoracolumbar of the spine
Requires high cardiac output and skeletal muscle activity
During fight or flight, what happens to blood vessels?
Non-essential (most) constrict
Coronary and skeletal muscle vessels dilate
The parasympathetic nervous system acts to ‘rest and digest’. Where is it anatomically? What happens to most vessels?
Out of the brain - cranial nerve 10 (vagus)
Most vessels dilate
What receptors are involved in the parasympathetic nervous system? Where are they? What type of chemicals do they receive?
M2 - blood vessels
M3 - Heart
Cholinergic
What receptors are involved in the sympathetic nervous system? What type of chemicals do they receive?
A1 - blood vessels
A2- blood vessels
B1- Heart
B2 - blood vessels
Before and during exercise, what 3 mechanisms can increase cardiac output?
Psychogenic response
Baroreflex
Exercise reflex - muscle/joint receptors feedback to cause autoregulation
What is hypovolaemia? What causes it?
Decreased blood volume
Haemorrhage, dehydration, or trapping of blood
How does hypovolaemic shock occur?
Hypoloaemia causes drop in venous return
Drop in preload
Decrease in cardiac output
Leads to organ failure
What is the body’s first reaction to hypovolaemia? What does the body do if this persists?
Baroreflex first
Then RAAS, starling’s law and spleen contracts
After blood loss, what happens to packed cell volume and blood protein levels?
Decreased
Blood is diluted
Fluid is replaced, proteins and cells also need replacing
Forward heart failure often leads to backwards heart failure. What is forward Heart failure?
Systolic failure
What does forward heart failure lead to? What are symptoms?
Thready (weak) pulse
Reduced CO
Breathless, fainting
What is backward heart failure? (Also known as congestive heart failure)
Inability to cope with preload
What are the results of backward heart failure?
Decreased venous pressure
Increased capillary pressure (leads to oedema)
What can often be the cause of backwards heart failure?
Faulty valves
How can heart failure lead to a viscous circle?
Compensatory mechanisms fail
Further stimulation of compensatory mechanisms
More water retention and vasonstriction
Increased workload on failing heart
What are natriuretic peptides?
Proteins which cause the excretion of sodium at the kidney
What do natriuretic peptides cause water to do?
Move out of the kidney via osmosis as sodium lost from kidney
What can natriuretic peptides be an indicator of?
Myocardial stretch
