2438971 Physiology Autonomic Nervous System and Senses Part 2 iBookstk

8/12/2019 2438971 Physiology Autonomic Nervous System and Senses Part 2 iBookstk

1/23

BIO 1414 Human Anatomy &

Physiology II

Unit 3 Autonomic Nervous System

and Senses

Part 2

By !o"ert #$ Allen% Proessor o Biology


2/23

Autonomic Nervous System (ANS)

' Involuntary or visceral nervous system

' !egulates the activity o

()ardiac *uscle+Heart,

(Smooth *uscle+ In Hollo- Organs,

' Blood Vessels

' Digestive System

' Bronchioles

' Sphincters(.lands

' Adrenal

' Digestive glands


3/23

ANS Divisions

' Sympathetic:

' ight or light!

' Activated during

emergencies" e#ercise or

vigorous physical

activity

' $evs up %ody torespond to situations

that upset homeostasis

' Parasympathetic:

' $est & Digest!

' $educes energy use

' Promotes:

(digestion o' 'ood

(storage o' energy

(elimination o'

astes

(homeostasis


4/23

Sympathetic *rigin

' /horacolum"ar

' Nerve i"ers originate "et-een /1 & 0


5/23

Parasympathetic *rigin

' +raniosacral

' Nerve 'i%ers emerge 'rom %rain & sacrum


6/23

Sympathetic

,nnervation o' Visceral -argets

' .angliaclose to s2inal cord

'Short% lightly myelinated2reganglionicneurons

'0ong% unmyelinated2ostganglionicneurons

Spinal

+ord


7/23

Sympathetic Neurotransmitters

' Preganglionic neurons

()holinergic + release acetylcholine ,


8/23

Sympathetic Neurotransmitters

' Adrenal medulla

(releases e2ine2herine & nore2ine2herine into "lood

(ie$ Adrenergic

' Postganglionic neurons

(release nore2ine2herineat target organs

(ie$ Adrenergic


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Adrenergic $eceptors

' 0ocated only on sym2athetic target organs

' !es2ond only to nore2ine2herine released "y2ostganglionic neurons +2recise eects, or

' 52ine2herine & nore2ine2herine released "y

adrenal medulla into "lood +general eects,


10/23

Adrenergic $eceptor -ypes' Alpha .:

' ,n alls o' %lood

vessels leading to

places other than

s/eletal muscles"%rain & lungs0

' Not on heart (cardiac

muscle)

' Alpha 2:

' *n mem%ranes o'

platelets0

' Beta .:

' *n heart (cardiac

muscle) & /idneys

' Beta 2:

' *n coronary arteries"%ronchioles & on

smooth muscle alls

o' digestive &

urinary systems


11/23

Adrenergic $eceptor 1''ects' Alpha .:

' 1#cites (constricts)

smooth muscles in

certain %lood vessels

& in spinctersdirecting %lood to

s/eletal muscles

' Dilates pupils0

' Alpha 2:

' Promotes %lood

clotting

' Beta .:

' +ardiac uscle

,ncreases heart rate

& strength

' Beta 2:' Depresses (dilates)

smooth muscle in

%ronchioles &

coronary arteries

increasing %lood 'lo

to heart and air 'lo

to lungs0


12/23

Parasympathetic

,nnervation o' Visceral -argets

' .anglia close to or on target organs

' Preganglionic neurons long

' Post ganglionic neurons short


13/23

Parasympathetic Neurotransmitters

' Preganglionic neurons release acetylcholine

)holinergic


14/23

Parasympathetic Neurotransmitters

' Postganglionic neurons release

acetylcholine )holinergic


15/23

+holinergic $eceptors

' #ound on s6eletal muscle cells regulated "y

motor neurons$

otor Neuron


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+holinergic $eceptors

' #ound on dendrites & cell "odies o2ostganglionicneurons o "oth sym2athetic

and 2arasym2athetic divisions o ANS$

' #ound on2arasym2athetictarget organs$


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+holinergic $eceptor -ypes

' Nicotinic:

' *n s/eletal muscle

cells' *n postganglionic

dendrites & cell

%odies in %oth

sympathetic &

parasympathetic

' Almost alays e#cite

' uscarinic:

' *n all target organs

o' parasympathetic' ay e#cite or

decrease activity

depending on target


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uscarinic $eceptor 1''ects

' +ardiac uscle Slos heart rate and

strength o' contraction

' Digestive System ,ncreases digestive

activity including secretions & peristalsis0

' ,ncreases 'lo o' %lood to liver" pancreas

& digestive organs %y vasodilation o'appropriate vessels0

' 1ye +auses constriction o' ,ris


19/23

Bloc/ing Agents

' Interere -ith stimulatory or de2ressingeects o neurotransmitters "y "loc6ing the

rece2tors on target organs$

Normal neurotransmitter can3t %ind ith receptor %ecause

%loc/er covers the %inding site0

Bloc/er


20/23

Adrenergic Bloc/ers

' Bloc6 rece2tor "inding sites 2reventing the

"inding o e2ine2herine or nore2ine2herine

' Beta 1"loc6ers on heart(2revent heart rate increase & arrhythmias in

cardiac 2atients -ithout interering -ith other

sym2athetic eects$

(57am2les

' Ace%utolol(Sectral)" etoprolol(4opressor)or

,nderal0


21/23

Adrenergic Bloc/ers

' Al2ha 1"loc6ers

(8ecrease "lood 2ressure in 2atients -ith

hy2ertension -ithout interering -ith othersym2athetic eects$

(57am2le

' Phentolamine


22/23

+holinergic Bloc/ers

' *uscarinic "loc6ers

(Bloc6 2arasym2athetic eects on target organs(57am2le

' Atropine

' 5sed topically during eye e#ams to dilate pupils

' Sometimes used prior to surgery to reduce

salivation & respiratory secretions


23/23

Ac/noledgements

ost o' the 'igures used in this presentation came 'rom the Ben6amin +ummings Digital 4i%rary

Version 207 'or 8uman Anatomy & Physiology" i'th 1dition0 *ther 'igures came 'rom pu%licdomain internet sources and so'tare in the possession o' the author0

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2438971 Physiology Autonomic Nervous System and Senses Part 2 iBookstk