PNS

Question 1

myenteric plexus

Answer 1

increases tonic and rhythmic contractions

Question 2

submucosal plexus

Answer 2

increases secretory activity and absorption

Question 3

adrenal medulla

Answer 3

releases NA and A

Question 4

sympathetic

Answer 4

short and long, Ach and NA, T1-L2

Question 5

parasympathetic

Answer 5

postganglionic neuron close to target, only ACh, (nic, then musc), cranial and S2-4

Question 6

LHRH or GnRH

Answer 6

Luteinizing hormone-releasing hormone or Gonadotrophin releasing hormone

Question 7

Muscarinic 2 autoreceptor

Answer 7

inhibits synaptic transmission

Question 8

Muscarinic 2 R

Answer 8

vagus nerve acts on them, found in heart, slow down hear rate by slowing the speed of depolarisation

Question 9

Muscarinic 3 R

Answer 9

stimulates, found in exocrine glands

Question 10

Muscarinic 1 R

Answer 10

stimulates, in gut tract and bladder

Question 11

Alpha 1

Answer 11

stimulates, in blood vessels, gut, bladder

Question 12

Alpha 2 R

Answer 12

inhibits,as autoreceptor decreases the release of NA, or in vascular smooth muscle , also in CNA - where it can produce analgesia

Question 13

Beta 1

Answer 13

stimulates, only in heart, increases heart rate (chronotropic) and force (ionotropic)

Question 14

Endothelium derived relaxation factor is…

Answer 14

Nitric oxide, causes relaxation of smooth muscle and platelet inhibition

Question 15

At sympathetic ganglion there is co-transmission:

Answer 15

Nicotinic ACh Rs mediate fast depolarisation , LHRH causes slow depol, M2 muscarinic and opioid Rs mediate slow hyperpolarisation

Question 16

adrenal gland is composed of..

Answer 16

cortex and medulla- catecholamines cause vasoconstriction and tachycardia

Question 17

Muscarinic receptors in the heart are located in atria and conduction system

Answer 17

are innervated by vagus nerve, mostly the sino-atrial and atrio-ventricular nodes and the atria. cause slowing of conduction

M receptor activation slows heart rate by slowing the spontaneous depolarisation of pacemaker cells

not force as this is ventricular!

Question 18

The eye: muscarinic receptors control pupil size and accommodation

Answer 18

ciliary muscle contracts, releasing the lens, which relaxes into a “fat” shape, good for near vision (accommodation)

Question 20

Cabachol is a muscarinic agonist

Answer 20

for both nic and musc , is resistant to choline esterases

Question 21

Pilocarpine

Answer 21

is a muscarinic agonist, resistant to choline esterases

Question 22

Therapeutic use of muscarinic agonists

Answer 22

Glaucoma- pilocarpine eye drops

In glaucoma an increased intraocular pressure leads to retinal damage. Muscarinic agonist are helpful because pinpoint pupils (miosis) and ciliary spasm improve the drainage of aqueous humour.

Relieve dry mouth (xerostomia; pilocarpine)

Question 24

Atropine causes..

Answer 24

• CNS: antiemetic (motion sickness); less tremor in Parkinson’s; excitation (toxic doses); cognitive impairment in elderly
• Eye: pupil dilatation (mydriasis); paralysis of accommodation, intraocular pressure may rise- glaucoma
• Secretions reduced: saliva, tears, sweat, bronchi, GI
• Smooth muscle relaxed (bronchi, GI tract)
• Heart: may increase heart rate; no effect on blood vessels
• Urinary retention

Question 25

Many common drugs (antipsychotics, antidepressants, antihistamines)

Answer 25

can block muscarinic receptors

Question 26

Therapeutic uses of muscarinic antagonists

Answer 26

Anaesthesia: Hyoscine- Scopolamine: pre-medication (sedation, less secretions) or to reduce effects of ChE inhibitors and vagus stimulation induced by surgery of visceral organs and against Motion sickness

• Urinary urgency & incontinence =oxybutynin
• Tropicamide= eye drops to induce mydriasis and ciliary muscle paralysis for retinal examination

Question 27

Noradrenaline in the brain..

Answer 27

Thalamus, hypthalamus, septum, amygdala, cerebelum, pituitary

Question 28

Dopamine Beta hydroxylase

Answer 28

catalyses dopamine-> noradrenaline

inhibited by disulfiram

Disulfiram is used to treat cocaine treatment, because excess dopamine causes anxiety and increased bp- unpleasant

Disulfiram is also used to treat alcoholism- bc is also inhibits acetyl-dehydrogenase- gives a hangover feeling

Question 29

L- Dopa to Dopamine

Answer 29

Dopa- decarboxylase

• inhibited by carbidopa

Carbidopa is given to Parkinson’s patients- allows more L-Dopa to cross BBB, because catabolism in the periphery is reduced, doesnt cross BBB itsself

Question 30

Pheochromocytoma is a neuroendocrinetumor of the medulla of the adrenal gland

Answer 30

It results in an over-production of catecholamines.

Alpha- methyl - p- tyrosine is used to treat it. It inhibits tyrodine hydroxylase whic is the enzyme that converts tyrosine to L-dopa