The Autonomic Nervous System (ANS)

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created 7 years ago by winnieto89
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1

ANS consists of

motor neurons that innervate smooth and cardiac muscle and glands to ensure optimal functioning of body at subconscious level

2

Somatic

effectors: skeletal muscles
group A fibers extends in spinal or cranial nerve to skeletal muscle
all somatic motor neurons release ACh and effects are always stimulatory

3

Autonomic

effectors: cardiac, smooth, glands
2 neuron chain (pre and post ganglionic neuron)
pre- releases ACh whilepost- releases ACh or NEP and can be inhibitory of stimulatory

4

Dual innervation

allows for homeostasis

5

parasympathetic

digestion, pooping, conserving body energy
relaxed state
long preganglionic fibers from brain to the sacrum

6

sympathetic

fight or flight response
preganglionic fibers pass through white rami communicantes and enter the trunk ganglia before targeting sweat glands, arrector pilli, vascular smooth muscle
23 paravertebral ganglia in the sympathetic trunk

7

pathway to head

skin and blood vessels -> stimulate dilator muscles of iris -> inhibit nasal and salivary glands -> smooth muscle of upper eyelid

8

thorax pathway

heart, thyroid gland, lungs, esophagus

9

abdomen pathway

postganglionic fibers: stomach, liver, spleen, kidneys

10

pelvis pathway

large intestine, bladder, reproductive organs

11

adrenal medulla

some pre-fibers pass without synapsing

12

medullary cells

can secrete NPE and EP into blood

13

visceral reflex

has 2 neurons in motor pathway: cholinergic fibers and adrenergic fibers

14

cholinergic fibers

nicotinic: found on sarcolemma of skeletal muscle cell
muscarinic: found on all effector cells, effects of ACh can be excitatory or inhibitory

15

adrenergic fibers

release NEP and has alpha and beta receptors

16

DRUGS- atropine

anticholinergic used to prevent salivation during surgery and dilating pupils for examination

17

Neostigmine

inhibits ACh and treats Myasthenia gravis (neuromuscular disorder)

18

OTC drugs for colds

stimulates alpha-adrenergic receptors

19

autonomic divisions

most visceral organs have dual innervation which allows for dynamic equilibrium

20

sympathetic tone

keeps blood vessels in continual state of partial constriction

21

parasympathetic tone

relaxes, overridden during times of stress

22

sympathetic division controls

thermoregulation, release of renin, metabolic effects

23

localized effects

parasympathetic: short lived, ACh quickly destroyed

24

diffuse effects

sympathetic: long lasting, body wide
NE inactivated slower than ACh because NE and EPE prolong effects

25

control of ANS function

hypothalamus: main center of ANS activity
others: cerebral cortex, reticular formation, and spinal cord

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hypothalamic controls

direct or indirect; heat, BP, balance, emotional stages, biological drives

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cortical controls

voluntary controls of visceral activities

28

biofeedback

controlling and managing stress, awareness of physiological condition and goal is to conscious change it

29

hypertension

high BP

30

raynaud's disease

exaggerated vasoconstrictions in fingers and toes (pale then blue)

31

autonomic dysreflexia

life threatening, BP skyrockets