Lecture 17- the autonomic nervous system

Question 1

what is the purpose of the autonomic nervous sytem?

Answer 1

innervates organs whose functions are not usually under voluntary control

Question 2

where does the sensory info get processed?

Answer 2

hypothalamus, limbic system, spinal cord, medulla

Question 3

reflexes are important for autonomic control, what can they evoke changes in?

Answer 3

autonomic output (negative feedback or feedforward)

Question 4

what is the autonomic system?

Answer 4

actions involving involuntary control

Question 5

what are examples of conscious control?

Answer 5

pee
heart rate can be controlled through meditation

Question 6

what do visceral effectors do?

Answer 6

they adjust their activity to match the bodys needs to maintain homeostasis
they don’t need the ANS in order to function

Question 7

what is the general autonomic nerve pathway?

Answer 7

CNS –> preganglionic fiber –> autonomic ganglion –> postganglionic fiber –> effector organ

Question 8

what is a ganglion?

Answer 8

a mass or group of neuronal cell bodies. knot of cell bodies

Question 9

in post ganglions do we have synapses?

Answer 9

we have networks of synapses (SOOO MANY)

Question 10

what does the autonomic nervous system divide into?

Answer 10

sympathetic nervous system
parasympathetic nervous system

Question 11

in the sympathetic nervous system where do the cell bodies and axons of preganglioinics originate?

Answer 11

thoracic (T1) and lumbar (L2) regions of the spine

Question 12

what can be said about sympathetic nervous system preganglionic and postganglionic fibers?

Answer 12

preganglionic fibers are short
postganglionic fibers are long

Question 13

what makes the sympathetic nervous system diverse?

Answer 13

there are many routes and many places for a preganglion to synapse

Question 14

what are the 3 routes of axons after they exit spinal cord?

Answer 14

1. make a synapse in a sympathetic chain ganglion
2. pass through SCG and synapse in the adrenal medulla
3. pass through SCG and synapse in a collateral ganglion

Question 15

what neurotransmitters do most preganglionic fibres and postganglionic fibers release in the sympathetic nervous system?

Answer 15

preganglionic fibres release ACh
postganglionic fibres release norepinephrine

Question 16

what kinds of receptors does the postsynaptic ganglion and the target cell have? SNS

Answer 16

nicotinic receptors (for ACh)
adrenergic receptors (for norepinephrine)

Question 17

why might the postganglionic neuron release ACh? SNS, its uncommon

Answer 17

releases ACh in sweat glands

Question 18

what structure is a modified sympathetic ganglion?

Answer 18

adrenal medulla

Question 19

where do parasympathetic nervous system fibres originate from?

Answer 19

cranial and sacral areas of CNS

Question 20

what is the structure of preganglionic fibres and postganglionic fibres in parasympathetic nervous system?

Answer 20

preganglionic fibers are longer
postganglionic fibers are very short

Question 21

what neurotransmitters do most preganglionic fibres and postganglionic fibers release in the parasympathetic nervous system?

Answer 21

preganglionic fibers release ACh
postganglionic fibers release ACh

Question 22

what is the difference between the sympathetic nervous system and parasympathetic nervous system?

Answer 22

SNS branches many times sto synapse on many different postganglionic neurons more divergence
PNS branches to synapse on postganglionic neurons, thus has more control over target organs because theres less divergence

Question 23

how many cranial nerves are in PNS? how many have parasympathetic function

Answer 23

12 total
4 have PNS function

Question 24

what are the 4 cranial nerves with parasympathetic function?

Answer 24

oculomotor nerve: control the lens and pupil of the eye
facial nerve: tear glands, salivary glands, nasal glands
glossopharyngeal nerve: salivary glands
vagus nerve: innervates the viscera (organs)

Question 25

why is the vagus nerve considered to be wondering? many of these sensory afferents project topographically to what tract in the brainstem? what number cranial nerve is it?

Answer 25

innervates all organs except adrenal medulla and some parts of the colon nucleus of the solitary tract in brainstem 10th cranial nerve

Question 26

where is the sensory info processed in vagus nerve? what information does it carry?

Answer 26

processed within the nucleus of the solitary tract carries efferent (PNS) information to regulate organ function

Question 27

what has a longer lasting effect?

Answer 27

SNS because ACh quickly breaks down and norepinephrine breakdown is slower (it circulates around for awhile)

Question 28

what does the SNS activate?

Answer 28

adrenal medulla to release large amounts of epinephrine

Question 29

how do we predict the effect of SNS and PNS?

Answer 29

SNS is fight or flight PNS is rest and digest

Question 30

if youre really stressed out, in what state will the SNS and PNS be in?

Answer 30

SNS will be heightened but PNS will never turn off, the volume of it will just decrease

Question 31

effect of sympathetic nervous system and parasympathetic nervous system on the heart?

Answer 31

SNS: increased rate, increased contraction PNS: decreased rate, decreased force of contraction

Question 32

effect of sympathetic nervous system and parasympathetic nervous system on eyes?

Answer 32

SNS: dilation of pupil and not at all significant for refocusing lens PNS: constriction of pupil and adjustment of eye for near vision

Question 33

effect of sympathetic nervous system and parasympathetic nervous system on exocrine pancreas?

Answer 33

SNS: inhibition of pancreatic exocrine secretion PNS: stimulation of pancreatic exocrine secretion

Question 34

effect of sympathetic nervous system and parasympathetic nervous system on salivary glands?

Answer 34

SNS: stimulation of small volume of thick saliva rich in mucus PNS: stimulation of large volume of watery saliva rich in enzyme

Question 35

compare and contrast the effects of SNS and PNS on the heart, eyes, and salivary glands

Answer 35

antagonistic (working against eachother) heart, eyes complimentary (did teh same thing) salivary glands: both increased saliva, different types of saliva but still both produced itw

Question 36

what is a good example of a complimentary response in PNS and SNS?

Answer 36

male sexual response: PNS responsible for erection SNS responsible for ejaculation

Question 37

what parts of the body only receive sympathetic intervention?

Answer 37

adrenal medulla sweat glands smooth muscle of most blood vessels

Question 38

what 4 CNS centres contribute to autonomic regulation?

Answer 38

limbic system hypothalamus brain stem spinal cord