Autonimic Nervous System

Front 1

homeostasis

Back 1

steady state of bodily function centered around some set point

Front 2

allostatis

Back 2

stability through change

Front 3

primary control of motor actions in ANS vs. SNS

Back 3

ANS- involuntary
SNS- voluntary

Front 4

type of muscle effector in ANS vs. SNS

Back 4

ANS- smooth, cardiac, glandular tissue
SNS-skeletal

Front 5

number of neurons between CNS and effector in ANS vs. SNS

Back 5

ANS- two
SNS-one

Front 6

specialized junction between motor neuron and effector in ANS vs SNS

Back 6

ANS- typically absent
SNS- present

Front 7

mechanism of effector relaxation in ANS vs SNS

Back 7

ANS- opposing sympathetic and parasympathetic systems
SNS- inhibition of A alpha motor neurons

Front 8

major function Symp vs. Parasymp

Back 8

symp- fight or flight
parasymp- rest and digest

Front 9

transmitter in preganglionic neuron Symp vs parasymp

Back 9

acetycholine

Front 10

transmitter in postgang. neuron symps vs. parasymp

Back 10

symp- NE typically
parasymp- acetylcholine

Front 11

location of ganglia

Back 11

symp- close to spinal cord
parasymp- close to effector organ

Front 12

origin of preganglionic neurons

Back 12

symp-thoraco-lumbar
parasymp- cranio-sacral

Front 13

distribution

Back 13

symp-viscera and extremeties
parasymp-mainly viscera (internal)

Front 14

degree of divergence in effector innervation

Back 14

symp- varies with effector
parasymp-varies with effector

-depends if the effector requires precise control (ciliary muscles) or a more global operation (GI tract)

Front 15

degree of topographic organization

Back 15

symp-relatively low
parasymp-relatively high

Front 16

multi-units

Back 16

-multi units smooth muscle cells
-involve large number of postganglionic fibers, each with close contanct to the smooth muscle fibers
-provides precise control over contraction, provides independent control on contraction as well
-symp: vas deferens
-parasymp: ciliary muscles

Front 17

single-units

Back 17

-single unit smooth muscle cells
-involve small number of postganglionic fibers each of which contacts only a few muscle fibers.
-the muscle fibers that are not indirect contanct from these ganglion fibers receive transmitter via diffusion or gap junctions. Causing a concerted response.
-fibers will contract with synchrony
-symp:peripheral vasculature
-parasymp: GI tract

Front 18

topographic organization in parasymp

Back 18

each cranial nerve nucleus tends to control only a single end organ. giving good topographic organization

Front 19

topographic organization in symp

Back 19

intermediolateral cell column contains pregang neurons that innervate several different psotgang neurons directed toward different targets
-therefore the topographic organization is less discrete

Front 20

intermediolateral cell column

Back 20

within the lateral horn at thoracic and lumber levels of spinal cord
-this is where sympathetic pregang neurons are found

Front 21

Sympathetic postganglionic neurons found (4 places)

Back 21

-gang of paravertebral chain
-gang in gangionic connective trunk
-prevertebral gang via splanchnic nerve
-adrenal medulla

Front 22

paravertebral chain

Back 22

parallel to pregang location

Front 23

sympathetic nerve trunk (connective trunk)

Back 23

this is where axons travel down to go synapse and a distance from the spinal starting place

Front 24

splanchnic nerve

Back 24

pregang is innervated through this nerve which comes out through the chain and trunk

Front 25

adrenal medulla

Back 25

cells reach the adrenal medulla via the splanchnic nerve. Preganglions release NE or Epi here and it diffuses into the blood stream
-Ne mainly acts to reinforce actions of sympathetic nerves
-Epi has actions complementary to NE

Front 26

what kind of receptor for NE? for EPi?

Back 26

NE- alpha adrenergic receptors
Epi- beta adregeneric receptors

Both NE and Epi can act on both but they have a higher affinity to these

Front 27

Parasympathetic pre ganglionic neurons

Back 27

found in the brainstem cranial nerve nuclei 3 (oculomotor), 7 (facial), 9 (glossopharyngeal), 10 (vagus)

and sacral levels of spinal cord
-pregang travel via cranial nerves, sacral ventral roots, and pelvis splanchnic nerves and terminate on postgang neurons in ganglia close to target organ

Front 28

what does sympathetic nervous system innervate

Back 28

-viscera
-sweat glands
-blood vessels
-pilomotor smooth muscle

Front 29

opposing actions

Back 29

symp and parasymp typically mediate opposing actions on smooth muscle

-causes an integrated balance in organs

Front 30

pupil diameter

Back 30

determined by activity in
symp- dilatory fibers from superior cervical gang (mydriasis)
-parasymp- constrictor fibers from ciliary ganglion (miosis)

Front 31

how can you get pupil constriction

Back 31

-either by decrease of sympathetic activity or increase in parasympathetic tone

Front 32

miosis

Back 32

ciliary ganglion which are constrictor fibers in parasymp

Front 33

mydriasis

Back 33

superior cervical ganglion which are dilatory fibers in symp

Front 34

pupillary light reflex

Back 34

mediated by the parasympathetic and not the symp
mediated by:
-retinal gang cells
-pretectal area via optic nerve, optic chiams and optic tract (bilateral)
-accessory oculomotor nucleus pregang neurons (bilateral)
-ciliary gang postgang neurons (ipsilateral) via oculomotor nerve (cranvial nerve 3)
-pupillary ciliary muscle

Front 35

unilateral optic nerve damage

Back 35

-sensory
-will abolish the reflex in both eyes, but only when light is shown into the ipsilateral eye
-if light is shown in the eye without the lesion then you will get reflex in both eyes

Front 36

unilateral oculomtor nerve damage

Back 36

-motor
-will abolish the reflex in the ipsilateral eye regardless of where the light is shown

Front 37

atropine

Back 37

-drug that can supress pupillary light reflex
-blocks cholinergic receptors
-done during eye exams to doctor can get a clear view of the retina

Front 38

Heart rate

Back 38

control by integrated systems
-cardiac cells connected bygap junctions
-therefore coordinated contraction of muscle

Front 39

heart rate

Back 39

determined by specialized regions called nodes where cells have pacemker potentials and a lower threshold fro action potential generation

Front 40

SA node

Back 40

sinoatrial
top right atrium
main pacemaker
innervated by both para and symp

Front 41

AV node

Back 41

atrioventricular node
lower node
operates mainly when SA node is disabled
innervated by both para and symp

Front 42

parasymp innervation of heart rate

Back 42

derives from vagus nerve and only on SA and Va nodes

Front 43

vagal drive on heart rate

Back 43

lowers heart rate therefore lowering cardiac output
-bradycardia

Front 44

bradycardia

Back 44

lowering heart rate
parasymp tone

Front 45

sympathetic innervation of heart rate

Back 45

comes from paravertebral chain and extents beyonf the nodes to the cardiac muscel as well.
therefore symp can increase both heart rate (tactycardia) and increase the force of contractio
both increase cardiac output

Front 46

tachycardia

Back 46

increase heart rate
symp tone

Front 47

peripheral vascuar smooth muscle

Back 47

constricts due to the symp nervous system
this helsp to redistribute blood flow to heart and brain and raises blood pressure by increasing peripheral resistence
-lowering blood pressure would be achieved by reducing symp outflow from CNS

Front 48

enteroreceptors

Back 48

sensory fibers carry info from enteroreceptors that inform the CNS about the internal state of the body

Front 49

sensory cells in ANS

Back 49

-pseudiunipolar neurons with their soma in a cranial or dorsal root ganglion
-most are thin A gamma or C fibers
-sensory receptors in ANS include nociceptors, chemoreceptors, and mechanireceptors

Front 50

chemoreceptors

Back 50

lie in carotid body between internal and external branches of the carotid artery

Front 51

oxygen chemoreceptors

Back 51

carotid body
respond mainly when blood oxygen levels fall
-release transmitter onto afferents(when oxygen levels fall) of the glossopharyngeal nerve (9) which projects to the NTS

Front 52

NTS

Back 52

nucleus of solitary tract
where nerve 9 projects
alters the activity of reticulospinal neurons to increase respiratory rate and increase blood flow to the brain (to increase back up the oxygen)

Front 53

mechanoreceptors

Back 53

those that detect blood pressure lie within the caroti sinus of carotid artery (within the elastic wall of carotid artery)
-activated by teh expansion of vascular smooth muscle that accompanies increased blood vlume or pressure
-transduce pressure info =baroreceptors

Front 54

baroreceptors

Back 54

receptors that transduce pressure information
=ascending fibers from baroreceptors join cranial nerve 9 and 10 and terminate within the NTS

Front 55

visceral afferent signals

Back 55

-cardovascular, resp. , GI motility
- come from the vagus and 9 nerves and send to caudal NTS

Front 56

efferents of NTS

Back 56

include ascending inputs to other nuclei that regulate autonomic function suchas the hypothalamus and limbic system
-they also may polysynaptic connections to symp and parasymp pregang neurons. These constitute the efferent limbs of reflex arcs for control of autonomic functions such as baroreceptor reflex

Front 57

mydriasis

Back 57

dilation

Front 58

optic tract damage

Back 58

weakened reflex

Front 59

lesion on oculomotor nerve

Back 59

never can get a response in ipsilateral eye

Front 60

decrease mean arteriol pressure causes what

Back 60

carotid sinus stops stretching, less excitatory drive to the NTS, parasymp tone decreases, causing decrease in Ach release on the hart nodes, therefore increase heart rate = increase cardiac output

Front 61

increase vagus nerve

Back 61

decrease heart rate

Front 62

baroreceptor reflex

Back 62

autonomic output control from NTS
(baroreceptor reflex in carotid sinus)--> 9 and 10 nerve --> NTS --> parasymp and symp

Front 63

increase mean arterial pressure

Back 63

-increase excitatory drive to caudal ventrolateral medulla which releases GABA inhibitory to rostral ventrolateral medulla, decreasing activity of the RVLM, decrease drive on reticulospinal tract which decreases symp ton from a decrease in firing of cells in spinal cord --> decrease in heart rate and symp caused a decrease in force of contraction

Front 64

RVLM

Back 64

rostral ventrolateral medulla

Front 65

CVLM

Back 65

caudal ventrolateral medulla

Front 66

what does a decrease in CVLM do to symp outflow

Back 66

decrease in CVLM output disinhibits RVLM which increases activity to the reticulospinal tract, increases symp

Front 67

baroreceptor afferents

Back 67

go from carotid sinus in carotid artery to the solitary nucleus (NTS) which is in the medulla which then innervates parallelly the CVLM/RVLM to reticulospinal tract and interneurons to vagus nerve to heart

Front 68

when arterial pressure are low, what happens to the vagus nerve frequency? symp cardiac impulses? symp vasoconstrictor fibers?

Back 68

vagus nerve frequency- diminishes
symp cardiac impulse- increases
symp vasocontrictors - become more active to increase peripheral resistence