Sympathetic Nervous System Flashcards
Name the physiological responses of the sympathetic nervous system (9)
Dilates pupils
Inhibits saliva production
Dilates bronchi
Accelerates heart
Stimulates adrenaline and noradrenaline release
Stimulates glucose release
Inhibits stomach, pancreas and intestines
Inhibits urination
Promotes ejaculation and ad ragma contractions
What affect does noradrenaline release have on the heart?
Increased:
Force of contraction
Rate of contraction
Rate of relaxation
What is positive inotropy?
Increased Force of cardiac contraction
What is positive chronotropy?
Increased Rate of contraction
What is positive lusitropy?
Increased Rate of relaxation
What is the affect of noradrenaline or adrenaline increase on blood vessels?
Artery narrowing
What are varicosities?
Bulges containing transmitters stored in vesicles
What is the effect of increased adrenaline on certain arteries like the coronary and skeletal muscle?
Relax
What are the effects of sympathetic nerve activation on the bladder, uterus and smooth GI muscle?
Relax
What are the effects of the sympathetic nervous system on the kidney?
Juxtaglomerular apparatus increases renin release
Where is the juxtaglomerular apparatus located?
Between afferent and efferent renal arteries
What does renin do?
Converts angiotensinogen -> angiotensin 1-> angiotensin 2
What is angiotensin 2?
A very potent vasoconstrictor that also increases circulating blood volume and affects cardiac remodelling
What are the effects of the sympathetic nervous system on the liver and skeletal muscle?
activation of phosphorylase
Increased glycogenolysis
Increased lipolysis-> increased glucose and TCA cycle intermediates
What are the effects of the sympathetic nervous system on the eye?
Contracts radial muscle (wide pupil)
Increases aqueous humour production (tears)
What are the effects of the sympathetic nervous system on sweat and hair?
Piloerection (hair standing up)
Increased sweat production (mediated by ACh not noradrenaline)
In alpha adrenergic receptors give the order of potency of noradrenaline, isoprenaline and adrenaline from most potent to least potent
Noradrenaline
Adrenaline
Isoprenaline
In beta adrenergic receptors give the order of potency of noradrenaline, isoprenaline and adrenaline from most potent to least potent
Isoprenaline
Adrenaline
Noradrenaline
What are the 3 types of alpha 1 receptors?
A
B
D
What are the 3 types of alpha 2 receptors?
A
B
C
What are the 3 types of beta receptors?
123
What type of receptors are adrenoceptors?
G protein coupled receptors
Give the enzymes, agonists and antagonists for the alpha 1 receptor
Phospholipase C
Phenylephrine
Oxymetazoline
Prazosin
Doxazosin
Tamsulosin (1a)
Give the enzymes, agonists and antagonists for the alpha 2 receptor
Adenylate cyclease (Gi)
Clonodine
Yohimbine
Give the enzymes, agonists and antagonists for the beta 1 receptor
Adenylate cyclase (Gs)
Dobutamine
Atenolol
Give the enzymes, agonists and antagonists for the beta 2 receptor
Adenylate cyclase (Gs)
Salbutamol
Salmeterol
Clenbuterol
Propranolol
Give the enzymes, agonists and antagonists for the beta 3 receptor
Adenylate cyclase (Gs)
Mirabegron
What physiological responses take place when the alpha 1 adrenoreceptor releases calcium?
Vascular smooth muscle contraction, contraction of iris muscle, promoter muscle and seminal vesicles
What happens if the transmitter release in the alpha 2 adrenoceptor is inhibited?
Decreased cAMP
What does cAMP do to the pacemaker region of the heart?
Binds and makes them depolarise quicker
What are the pacemaker regions in the Heart?
SAN/AVN
Sinoatrial node/ atrioventricular node
What happens when cAMP activates protein kinase A?
It puts a phosphate group on a protein and alters the protein function (turns on potassium and calcium channels)
In smooth muscle cells, what does increased cAMP lead to?
Decreased calcium release, increased K+ activity, decreased myosin light chain kinase and therefore decreased smooth muscle contraction
What is inhibited by protein kinase A?
Myosin light chain kinase
