Autonomic Nervous System

Question 1

two divisions of motor division of PNS:

Answer 1

somatic

autonomic

Question 2

somatic NS

Answer 2

• AP comes from lateral gray horn of SC & is carried by myelinated neuron
• excitatory response in skeletal muscle, never inhibitory
• at effector, NT released is acetylcholine, causes muscle to contract

Question 3

autonomic NS

Answer 3

• AP comes from anterior gray horn of SC (cell body is in lateral horn or brainstem)
• 2 neuron system:
  preganglionic neuron synapses w postganglionic neuron at autonomic ganglion
• effectors are smooth muscle, cardiac muscle, glands

Question 4

preganglionic neuron

Answer 4

• has origins in CNS
• myelinated
• releases acetylcholine at autonomic ganglion

Question 5

postganglionic neuron

Answer 5

• extends from synapse at ganglion outside of CNS to the effector/ target tissue
• unmyelinated
• NT released is either acetylcholine or norepinephrine

Question 6

divisions of the ANS

Answer 6

2 main:
- sympathetic
- parasympathetic
also enteric division

Question 7

sympathetic division

Answer 7

aka thoracolumbar division
- origins in lateral horn of SC from T1-L2, exit through ventral root
- uses 2 types of ganglia:
sympathetic trunk ganglia/chain ganglia
prevertebral/collateral ganglia

Question 8

sympathetic trunk ganglia/chain ganglia

Answer 8

chains of ganglia close to SC

form 2 chains on either side of SC

Question 9

prevertebral ganglia/collateral ganglia

Answer 9

closer to effectors or target tissues

Question 10

there are 4 routes of sympathetic axons; tell me about the 1st

Answer 10

1. preganglionic leaves CNS w spinal nerve, synapse in chain ganglion, postganglionic nerve re-joins spinal nerve at anterior ramus
   target: skin of neck, trunk limbs

Question 11

there are 4 routes of sympathetic axons; tell me about the 2nd

Answer 11

2. exit CNS w spinal nerve, synapse in chain ganglion, post ganglionic neuron called a sympathetic neuron and goes directly to target tissue
   target: heart & lungs

Question 12

there are 4 routes of sympathetic axons; tell me about the 3rd

Answer 12

3. preganglionic neuron passes through chain ganglion w/o synapse and instead synapses in collateral ganglion
   - after preganglionic nerve leaves sympathetic chain ganglion, it is called the splanchnic nerve
   target: abdominopelvic organs

Question 13

there are 4 routes of sympathetic axons; tell me about the 4th

Answer 13

4. preganglionic neuron bypasses both chain ganglion and collateral ganglion ad synapses w cells of adrenal medulla. this stimulates them to release epinephrine and norepinephrine into the blood where they act as hormones

Question 14

parasympathetic division

Answer 14

aka craniosarcal division

- cell bodies assoc w nuclei of cranial nerves III, VIII, IX, X and also lateral gray horn of SC S2-S4

Question 15

terminal ganglia

Answer 15

where preganglionic axons synapse w postganglionic axons in the parasympathetic NS

Question 16

pelvic splanchnic nerves

Answer 16

supply smooth muscle and gland control of colon, bladder and reproductive organs

Question 17

cranial nerve III is responsible for

Answer 17

ciliary muscles, sphincter pupillae

Question 18

cranial nerve VII is responsible for

Answer 18

glands for tears and nasal secretions

Question 19

cranial nerve IX is responsible for

Answer 19

parotid salivary gland

Question 20

cranial nerve X is responsible for

Answer 20

• has many branches

- heart, pulmonary, GI systems

Question 21

NT secreted by sympathetic preganglionic and postganglionic neurons

Answer 21

pre: cholinergic
post: adrenergic

Question 22

NT secreted by parasympathetic preganglionic and postganglionic neurons

Answer 22

pre: cholinergic
post: cholinergic

Question 23

cholinergic receptors

Answer 23

• acetylcholine can be either excitatory or inhibitory, depending on which receptors them bind to
  2 classes: nicotenic and muscarinic

Question 24

nicotenic receptors

Answer 24

• excitatory only
• open Na+ channels
• located on cell bodies of postganglionic neurons in both sympathetic and parasympathetic
• also found on muscle cell plasma membranes at the neuromuscular junction

Question 25

muscarinic receptors

Answer 25

- excitatory or inhibitory response - found on effector cells that respond to acetylcholine from postganglionic neurons (smooth muscle, cardiac muscle, glands)

Question 26

adrenergic receptors

Answer 26

- bind w epinephrine & norepinephrine - found in most sympathetic NS effectors bc postganglionic symp neurons release norepinephrine 2 classes: Alpha receptors (A1, A2) and Beta receptors (B1, B2) A1, B1 are for excitation A2, B2 are for inhibition diverse actions, dependant on receptor and tissue

Question 27

baroreceptors

Answer 27

receptors in walls of large arteries that detect stretch and changes in BP

Question 28

generalizations of the ANS

Answer 28

1. both divisions produce stimulatory and inhibitory effects 2. most organs receive dual innervation 3. divisions usually have opposing effects 4. produce cooperative effects (can stimulate several organs in a system to cooperate) 5. general (symp bc of adrenal hormones) vs. local (parasymp) effects 6. rest (parasymp: SLUDD) vs action (symp)

Question 29

SLUDD

Answer 29

``` salivation lacrimation urination digestion defecation ```

Question 30

enteric division of ANS (sort of)

Answer 30

has nervous plexuses located in walls of digestive tract that contain nerve cell bodies vs just axons - there are 3 points of nervous input into the GI tract

Question 31

3 points of nervous input into GI tract:

Answer 31

1. digestive info goes to CNS 2. ANS motor neurons connect CNS to digestive tract for control of smooth muscle, gland secretions 3. Enteric neurons are controlled through autonomic reflexes

Question 32

3 major types of enteric neurons

Answer 32

sensory motor interneurons

Question 33

enteric sensory neurons

Answer 33

detect stretch and chemical composition of contents

Question 34

enteric motor neurons

Answer 34

stimulate or inhibit smooth muscle and control gland secretions

Question 35

enteric interneurons

Answer 35

connect sensory & motor neurons | - help create reflex loops to allow for rapid response to info that has been detected