Autonomic nervous system Flashcards
Can you suggest clinical uses of these sympathetic blocks: thoracic sympathectomy, lumbar sympathectomy and coeliac plexus block?
Thoracic sympathectomy is used for the treatment of severe Reynaud’s phenomenon or hyperhidrosis (sweaty palms).
Lumbar sympathectomy is used for circulatory insufficiency of the lower limb or phantom limb pain.
Coeliac plexus block is used for the pain associated with upper GI malignancy or acute or chronic pancreatitis.
When reversing non-depolarizing neuromuscular blockade, what classes of agent are given, and why?
An anticholinesterase (neostigmine) is given to increase ACh levels. At the at the motor end-plate of the neuromuscular junction blocker (nicotinic) this reverses the effect of the muscle relaxant. Unwanted muscarinic effects of the ACh are prevented by the use of an agent such as atropine or glycopyrrolate.
What are the effects of the drugs atropine and adrenaline on the eye?
Both cause pupil dilation and blurred vision, by parasympathetic block (atropine) and sympathetic stimulation (adrenaline).
What is the effect of spinal block for Caesarean section on blood pressure?
How may this be managed?
What additional effect does high spinal block have on the cardiovascular system?
Blood pressure falls due to associated sympathetic block that produces widespread vasodilation (T4–L2).
Fluid loading and use of a directly acting vasoconstrictor such as phenylephrine.
More profound hypotension due to greater sympathetic block and bradycardia from loss of sympathetic supply to the heart (T1 - 4).
T
How are cholinergic receptors sub-divided?
Cholinergic receptors are subdivided into nicotinic andmuscarinic receptors.
How are cholinergic receptors sub-divided?
Cholinergic receptors are subdivided into nicotinic andmuscarinic receptors.
