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Flashcards in PNS Deck (31):
1

myenteric plexus

increases tonic and rhythmic contractions

2

submucosal plexus

increases secretory activity and absorption

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adrenal medulla

releases NA and A

4

sympathetic

short and long, Ach and NA, T1-L2

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parasympathetic

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

6

LHRH or GnRH

Luteinizing hormone-releasing hormone or Gonadotrophin releasing hormone

7

Muscarinic 2 autoreceptor

inhibits synaptic transmission

8

Muscarinic 2 R

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

9

Muscarinic 3 R

stimulates, found in exocrine glands

10

Muscarinic 1 R

stimulates, in gut tract and bladder

11

Alpha 1

stimulates, in blood vessels, gut, bladder

12

Alpha 2 R

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

13

Beta 1

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

14

Endothelium derived relaxation factor is...

Nitric oxide, causes relaxation of smooth muscle and platelet inhibition

15

At sympathetic ganglion there is co-transmission:

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

16

adrenal gland is composed of..

cortex and medulla- catecholamines cause vasoconstriction and tachycardia

 

A image thumb
17

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

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! 

 

18

The eye:  muscarinic receptors  control pupil size  and accommodation 

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

 

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Cabachol is a muscarinic agonist

 for both nic and musc , is resistant to choline esterases

21

Pilocarpine 

is a muscarinic agonist, resistant to choline esterases

22

Therapeutic use of muscarinic agonists 

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)  

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Atropine causes..

• 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 

25

Many common drugs (antipsychotics, antidepressants, antihistamines) 

can block muscarinic receptors 

26

Therapeutic uses of muscarinic antagonists

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

27

Noradrenaline in the brain..

Thalamus, hypthalamus, septum, amygdala, cerebelum, pituitary

28

Dopamine Beta hydroxylase

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 

 

29

L- Dopa to Dopamine

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 

30

Pheochromocytoma is a neuroendocrinetumor of the  medulla of the adrenal gland 

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 

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