ANS Spinal Reflexes Part 1 (Slides 1-34, Quiz 1)

Question 1

What is a reflex?

Answer 1

-a rapid, predictable automatic response to a stimulus/message
-involuntary
-involves a receptor, the CNS, and an effector
-outside of conscious control

Question 2

define monosynaptic reflexes

Answer 2

-afferent in, efferent out
-only one junction

(whereas polysynaptic reflexes are afferent> interneuron(s) > efferent out)

Question 3

What are the 7 steps of a somatic reflex/reflex arc?

Answer 3

1) stimulus
2) receptor
3) sensory neuron
4) integration center
5) motor neuron
6) effector
7) response

Question 4

Where are interneurons located?

Answer 4

in CNS

Question 5

A skeletal m. contracts in response to…

Answer 5

being stretched

Question 6

Which nerve class is associated with a muscle spindle and sends APs when the muscle spindle fibers are stretched?

Answer 6

1a

Question 7

T/F: CNS inhibition of ANS output is common

Answer 7

true

Question 8

T/F: all neurons can decide to inhibit reflexes

Answer 8

false, only interneurons can do this

Question 9

Golgi tendon organs (GTO) are proprioceptive. They stimulate 1b fibers and often causes inhibition of __________ neurons. Autogenic inhibition is thought to be a protective mechanism preventing excess tension or for contributing to fine adjustments

Answer 9

alpha motor

Question 10

What is a withdrawal/flexor reflex?

Answer 10

-a somatic reflex
-involves a whole limb and several spinal segments
-painful stimuli from cutaneous receptors
-synapse on interneurons on the gray matter
-leave via multiple efferents to different muscles
-all primary afferents must bifurcate on the interneuron
-always polysynaptic

1 stimulus will have 1 afferent go in, multiple efferents go out. The interneuron spreads up and down to adjacent spinal segments, so it activates multiple different circuits. There will be withdrawal from stimulus w/o “checking in” with the brain

Question 11

What are some examples of crossed effects in reflexes?

Answer 11

-only 1 eye constricts with light when both eyes should constrict
-flex a limb to withdraw from pain and then fall over, contralateral limb extends and supports

Question 12

What are the 4 types of reflexes of the ANS?

Answer 12

1) somato-somatic reflex
2) viscero-visceral
3) somato-visceral
4) viscerosomatic

Question 13

What is the pupillary light reflex?

Answer 13

shine bright light in one eye and both pupils should constrict

Question 14

What are viscerosomatic reflexes?

Answer 14

-reflex between an organ and a closely related body part
-hard to pinpoint pain, sweaty, referred pain, muscle spasm

Question 15

Shoulder pain can later be diagnosed as….

Answer 15

gallbladder disease

Question 16

Flank pain is a precursor to what diagnosis?

Answer 16

kidney stones

Question 17

cardiac ischemia or hypoxia presents as….

Answer 17

L arm pain

Question 18

Fibers from cord segment T1 generally follows up the sympathetic chain to terminate in the….

Answer 18

head

Question 19

Fibers from cord segment T2 generally follows up the sympathetic chain to terminate in the….

Answer 19

neck

Question 20

Fibers from cord segment T3-T6 generally follows up the sympathetic chain to terminate in the….

Answer 20

thorax

Question 21

Fibers from cord segment T7-T11 generally follows up the sympathetic chain to terminate in the….

Answer 21

abdomen

Question 22

Fibers from cord segment T12-L2 generally follows up the sympathetic chain to terminate in the….

Answer 22

legs

Question 23

What spinal cord segments have lateral horns?

Answer 23

T1-L2

Question 24

The white ramus can be remembered as “white out” What classification of nerve fibers exit through here?

Answer 24

B fibers

Question 25

Parasympathetic fibers leave the CNS through cranial nerves 3, 7, 9, and 10; additional parasympathetic fibers leave the lowermost part of the spinal cord through the 2nd and 3rd sacral spinal nerves and occasionally the 1st and 4th sacral nerves. What nucleus does each CN 3, 7, 9, and 10 run through in brainstem?

Answer 25

CN 3 runs through Edinger-Westphal (EW) nucleus CN 7 runs through superior salivary nucleus CN 9 runs though the inferior salivary nucleus CN 10 runs through the dorsal motor nucleus of vagus (DMX nucleus)

Question 26

About 75% of all parasympathetic nerve fibers are in the....

Answer 26

vagus nerve

Question 27

Fibers that secrete ACh are said to be...

Answer 27

cholinergic

Question 28

Fibers that secrete NE are said to be....

Answer 28

adrenergic

Question 29

All preganglionic neurons are _____________ in both the sympathetic and parasympathetic NS

Answer 29

cholinergic

Question 30

T/F: ACh, when applied to the ganglia, will excite both sympathetic and parasympathetic postganglionic neurons

Answer 30

true!!!

Question 31

All/almost all of the postganglionic neurons of the parasympathetic NS are...

Answer 31

cholinergic

Question 32

Most of the postganglionic sympathetic neurons are...

Answer 32

adrenergic

Question 33

What type of transport is used to move ACh or NE from the soma (nissl bodies) to the axon terminal?

Answer 33

anterograde transport

Question 34

What are varicosities?

Answer 34

enlargements/swellings with neurotransmitter vesicles on the postganglionic axon

Question 35

2 functions of the eyes are controlled by the ANS (dual innervation). What are they?

Answer 35

1) the size of the pupillary opening within iris 2) the focus of the lens

Question 36

What is accommodation?

Answer 36

eye maintaining focus

Question 37

What muscle group helps with accommodation?

Answer 37

ciliary body (meridional fibers and circular muscle)

Question 38

Sympathetic stimulation contracts the ______________ of the iris which ________ the pupil

Answer 38

meridional fibers, dilates

Question 39

Parasympathetic stimulation contracts the ______________ of the iris to ___________ the pupil

Answer 39

circular muscle, constrict

Question 40

The parasympathetic NS controls the pupil as a reflex and it is stimulated when there is an excess of light. The response is to...

Answer 40

reduce the amount of light that hits photoreceptors by constricting the pupil

Question 41

In general, sympathetic stimulation increases the overall activity of the heart. This effect is accomplished by increasing both the....

Answer 41

rate and force of heart contraction (parasympathetic stimulation causes mainly opposite effects- decreased heart rate and strength of contraction)

Question 42

What is the average heart rate for adults?

Answer 42

70 bpm

Question 43

What is the average stroke volume for adults?

Answer 43

70 mL

Question 44

What is stroke volume?

Answer 44

volume of blood that leaves the heart

Question 45

Which ANS increases heart rate?

Answer 45

sympathetic NS

Question 46

Which ANS increases stroke volume (contracts with more force)?

Answer 46

sympathetic NS

Question 47

Which ANS contracts/constricts the tunica media to increase BP?

Answer 47

sympathetic NS

Question 48

Which ANS decreases heart rate?

Answer 48

parasympathetic NS

Question 49

Which ANS decreases stroke volume (don't need a lot of blood out of the heart)?

Answer 49

parasympathetic NS

Question 50

Which ANS dilates the tunica media in blood vessels to decrease BP?

Answer 50

parasympathetic NS

Question 51

What is the central autonomic network (CAN) composed of?

Answer 51

hypothalamic and extra-hypothalamic nuclei

Question 52

The single most important hypothalamic nucleus of the central autonomic network is the....

Answer 52

paraventricular nucleus (PVN)

Question 53

The ________________ descends from the hypothalamus down the brainstem to the spinal cord. It can influence and control the activity of parasympathetic and sympathetic nuclei along the way and projects to the IML in lateral horns- sympathetic out

Answer 53

dorsal longitudinal fasciculus (DLF)

Question 54

What ANS receptors are there for afferent activity in cardiovascular system?

Answer 54

baroreceptors (mechanoreceptors) within arteries and chemoreceptors sending info on pH (detects H+), carbon dioxide, oxygen (partial pressure) which initiates an AP

Question 55

Receptors and afferents from the aortic arch reach the brainstem via the ______ nerve

Answer 55

vagus (CN X)

Question 56

Receptors and afferents from the carotid artery enter via the ___________ nerve

Answer 56

glossopharyngeal (CN IX)

Question 57

Info goes to brainstem within which cranial nerves to synapse on the solitary nucleus?

Answer 57

CN X and CN IX

Question 58

Inputs from the heart/blood vessels synapse in the....

Answer 58

solitary nucleus

Question 59

The solitary nucleus relays info from the heart and blood vessels to the autonomic centers in the _______________ and sends down negative feedback to visceral motor neurons and ______ nucleus

Answer 59

reticular formation, DMX

Question 60

If chemoreceptors detect low oxygen, then the body wants to....

Answer 60

increase sympathetic NS

Question 61

If baroreceptors detect high BP, then the body wants to....

Answer 61

inhibit sympathetic NS and activate parasympathetic NS

Question 62

The tunica media only receives ___________ output

Answer 62

sympathetic

Question 63

What is the major source of excitatory input to sympathetic nerves controlling the vasculature?

Answer 63

rostral ventrolateral medulla (RVLM)

Question 64

A blood vessel that is neither constricted or dilated has weak or strong sympathetic tone?

Answer 64

weak sympathetic tone

Question 65

When does a blood vessel have no sympathetic input?

Answer 65

when its dilated

Question 66

When does a blood vessel have strong sympathetic tone?

Answer 66

when its constricted

Question 67

What 3 substances function as vasoconstrictors in blood vessels?

Answer 67

1) NE 2) ATP 3) neuropeptide Y (NPY)

Question 68

Which 2 substances regulate vasodilation in blood vessels?

Answer 68

ACh and calcitonin gene-related peptide (CGRP)

Question 69

Endothelial dysfunction and inflammation are associated with ______________ nerve activity

Answer 69

sympathetic

Question 70

2 separate neural mechanisms regulate respiration- one is responsible for ____________ control and the other for ___________ control

Answer 70

voluntary, autonomic (the voluntary control system is located in the cerebral cortex and sends impulses to the respiratory motor neurons via the corticospinal tracts, whole to automatic system is driven by a group of pacemaker cells in the medulla)

Question 71

Neurons in the cervical spinal cord activate the diaphragm via the __________ nerves

Answer 71

phrenic

Question 72

Neurons in the thoracic spinal cord activate the _________________ muscles

Answer 72

external intercostal

Question 73

T/F: inspiration is from low pressure to high pressure

Answer 73

false, its the opposite- high to low pressure

Question 74

When is the diaphragm the longest?

Answer 74

when its relaxed

Question 75

When is the diaphragm the smallest?

Answer 75

when its contracted

Question 76

T/F: inspiration is always active, you cannot have inspiration without muscle contraction

Answer 76

true

Question 77

T/F: expiration is always passive

Answer 77

false, not always

Question 78

The respiratory center is composed of several groups of neurons located bilaterally in the medulla oblongata and pons of the brainstem. 1) a dorsal respiratory group which is located in the dorsal portion of the medulla and mainly causes ____________ 2) a ventral respiratory group which is located in the ventrolateral part of the medulla and mainly causes _____________ 3) the pneumotaxic center which is located dorsally in the superior portion of the pons and mainly controls _____________________

Answer 78

inspiration, active expiration, rate and depth of breathing

Question 79

Where are most of the neurons located for the dorsal respiratory group?

Answer 79

solitary nucleus

Question 80

The pneumotaxic center is located in the dorsolateral pontine tegmentum, caudal to the inferior colliculus. Located within.....

Answer 80

nucleus parabrachialis

Question 81

Which nuclei is essential for maintaining a normal breathing pattern (switching between inspiration and expiration)?

Answer 81

respiratory nuclei/ nucleus parabrachialis

Question 82

When the pneumotaxic signal is strong (small/short volume), inspiration will last for 0.5 second, thus filling the lungs ________

Answer 82

slightly

Question 83

When the pneumotaxic signal is weak (large/long volume), inspiration will last for 5+ seconds, thus filling the lungs ___________

Answer 83

fully

Question 84

The function of the pneumotaxic center is primarily to limit ____________, which has a secondary effect of increasing the rate of breathing

Answer 84

inspiration

Question 85

Which nucleus is the ventral respiratory group found in?

Answer 85

nucleus ambiguos

Question 86

The neurons of the ventral respiratory group remain....

Answer 86

almost totally inactive during normal quiet respiration

Question 87

Which respiratory center operates as an overdrive mechanism during heavy exercise?

Answer 87

ventral respiratory group

Question 88

The hormones of the adrenal medulla are the....

Answer 88

catecholamines

Question 89

The adrenal medulla is formed from....

Answer 89

neural crest cells

Question 90

The adrenal medulla itself is a modified neural tissue. The medulla functions like a....

Answer 90

modified sympathetic ganglion (stress response)