ANS Flashcards
What is the sympathetic system?
Responds to stressful situations
Heart rate, blood pressure, contractions
What is the parasympathetic system?
Basal activities - ‘rest and digest’
Where on the spinal cord are the parasympathetic nerves compared to the sympathetic nerves?
Sympathetic nerves - central area
Parasympathetic - top and bottom
The X system has short, myelinated pre-ganglionic fibres, and long unmyelinated post ganglionic fibres.
The Y system has long , myelinated pre-ganglionic fibres, and short unmyelinated post-ganglionic fibres.
X = sympathetic Y = parasympathetic
In the parasympathetic system, for pre-ganglionic and post-ganglionic neutrons, what is the:
A)neurotransmitter used
B)receptor used
Pre-ganglionic - ACh and nAChR
Post-ganglionic - ACh and mAChR
In the sympathetic system, for pre-ganglionic and post-ganglionic neutrons, what is the:
A)neurotransmitter used
B)receptor used
Pre-ganglionic neuron - ACh and nAChR
Post-ganglia neuron - NA and adrenoceptors
What type of receptors are MAChRs?
G-coupled receptors
How are adrenal glands different in how they transmit signals?
They contain chromaffin cells.
On sympathetic stimulation the chromaffin cells release adrenaline into the bloodstream.
What is dysautonomia?
An ANS malfunction
What is a pheochromocytoma?
Cancer of the adrenal glands
What is the name for ACh synthesis and what substances are involved?
Choline acetyltransferase
Acetyl CoA + choline = acetylcholine + coenzyme A
What the name for ACh degradation and what substances are involved?
Acetylcholineterose
Acetylcholine = acetate + choline
What side effects could a non-selective mAChR drug cause?
Low heartbeat
Bronchoconstriction
Increased sweating
What is the acronym for drug side effects? What are these generally caused by and what can they can treated with?
S - salivation L - lacrimation - of lacrimal glands (tears) U - urination D - defecation G - GI upset E - Emesis - vomiting
Caused by over - stimulation of MAChRs (drug overdoes, nerve bases, magic mushrooms). Treated with anti-cholinergic agents.
What are varicosities?
Small nodes in the axonal network on the sympathetic post-ganglionic neutrons that are specialised for Ca2+ release.
After a noradrenaline transmitter has binded to an adrenoceptor, what two ways is it removed?
Uptake 1: back to the pre-synaptic terminal
Uptake 2: through the post-synaptic cell
What is salbutamol?
A beta2 - adrenoceptor - selective agonist
Used to promote relaxation in asthma
What three body parts are controlled by the sympathetic nervous system only?
Blood vessels
Liver
Adrenal medulla
How can you tell the difference between thyroxicosis and anxiety?
Thyroxicosis - warm and sweaty
Anxiety - cold and clammy
What is thyroxicosis?
Excessive thyroid hormones in the body.
Upregulate the number of adrenoceptors in the body, can cause high BP.
What is asthma?
An inflammatory disease.
High number of eosinophils (WBC0 gather in the lungs causing inflammation
Bronchial hyper-responsiveness
Hyper secretion of mucus
Patients have increase sympathetic drive - more ACh, more mAChRs, more bronchoconstriction
What treatments can be given for asthma and how do they work?
Relievers - bronchodilators e.g. Salbutamol - stimulate b2-adrenoceptors
Preventers - anti-inflammatory mediation
What is the name of the system which regulates blood pressure?
Sympathetic system
Also controlled by the renin-angiotensin system
What is the renin-angiotensin system?
If blood pressure and blood volume is low, kidney filtration (along with the liver, lungs and adrenal glands) drive back up the blood volume therefore blood pressure.
What is considered normal blood pressure, hypertension and hypotension?
Normal 120/80
Hypertension 140/90
Hypotension 90/60
Name four treatments that can be given for hypertension and how do they work.
ACE inhibitors - stop the renin-angiotensin system increasing blood volume. ACE is an enzyme released by the lungs to convert angiotensin to its active form.
Calcium blockers - reduce cardiac response
Diuretics - reduce blood volume therefore blood pressure
B-adrenoceptor blockers (beta blockers)- antagonists that reduce cardiac input and renin production.
A-adrenoceptor blockers - antagonists causing vasodilation
