Module 3: Lecture 7

Question 1

what are the two components of the nervous system?

Answer 1

1. central nervous system (CNS)
2. peripheral nervous system (PNS)

Question 2

what part of us is our central nervous system?

Answer 2

the brain and spinal cord

Question 3

what part of us is our peripheral nervous system?

Answer 3

nerve fibers
- all the extra nervous tissue, predominantly nerves

Question 4

what brings information either toward or away from the spinal cord?

Answer 4

the peripheral nervous system

Question 5

what does ‘afferent’ in regards to the peripheral nervous system mean?

Answer 5

you are carrying information towards the spinal cord
- ex. touch receptors - from periphery to the CNS

Question 6

what does ‘efferent’ in regards to the peripheral nervous system mean?

Answer 6

you are carrying information away from the spinal cord
ex. walking around - motor commands from CNS that allows us to move around and communicate

Question 7

what is the peripheral nervous system?

Answer 7

connection between the CNS and effectors/receptors located in other parts of the body

Question 8

when do we refer to specific nerve bundles?

Answer 8

when talking about the PNS

Question 9

what is a pathway/tract?

Answer 9

groups or bundles of nerves or axons within the CNS

Question 10

what are the two divisions of the efferent division of PNS?

Answer 10

1. somatic nervous system
2. autonomic nervous system

Question 11

what are the two divisions of the autonomic nervous system?

Answer 11

1. sympathetic nervous system
2. parasympathetic nervous system

Question 12

which systems of the efferent division do you have conscious and voluntary control over vs unconscious and involuntary?

Answer 12

conscious and voluntary- somatic
unconscious and involuntary- autonomic

Question 13

do the pathways of the efferent and afferent divisions utilize the same neurons?

Answer 13

no, different neurons

Question 14

what is the pathway of the afferent division?

Answer 14

• from a receptor to the CNS

Question 15

what is the pathway of the efferent division?

Answer 15

• carries information away from the CNS toward the end effector organs or muscles

Question 16

what does the somatic nervous system control?

Answer 16

skeletal muscles

Question 17

the cell bodies of the neurons of the somatic nervous system are located where?

Answer 17

in the brainstem and the ventral horn of the spinal cord
- spinal cord

Question 18

what are the neurons of the somatic nervous system?

Answer 18

motor neurons

Question 19

what does the autonomic nervous system innervate?

Answer 19

• all of your internal organs that have some sort of neural input on them

ex:
- the smooth and cardiac muscles
- glands
- adipose tissue, liver, other neurons from the gastrointestinal tract

Question 20

what is the structure of the afferent neuron in PNS?

Answer 20

• sensory receptor within the periphery that generates the action potential which will travel towards the CNS
• has a long peripheral axon which is the information traveling back to the CNS
• cell body located next to the CNS next to the spinal cord
• axon terminals project slightly into CNS

Question 21

what does a sensory receptor do?

Answer 21

generates an action potential in response to a stimulus

Question 22

how does an afferent neuron get into the CNS?

Answer 22

the touch receptor (sensory receptor) generated an action potential in response to that stimulus and then the axon terminals will project into the CNS, into the spinal cord, where it will synapse

Question 23

how does the cell body of an afferent neuron in PNS look like?

Answer 23

• adjacent to the spinal cord
• has no dendrites

Question 24

what is responsible for most of our neural tissue?

Answer 24

our interneurons
- around 99% of our neurons are interneurons

Question 25

what is the link between our afferent and efferent systems?

Answer 25

interneurons

Question 26

what is important to integrating peripheral responses to peripheral information?

Answer 26

interneurons ex. touch something hot --> interneurons relay signal to efferent neurons to withdraw hand (reflex)

Question 27

which part of efferent neurons are in which systems? why?

Answer 27

efferent neurons cross from CNS to PNS. the cell body is in the CNS, and the axons are in the PNS. this is because the signal originates in the brain or received from interneuron

Question 28

what does your autonomic nervous system control?

Answer 28

a whole host of organs - all of the internal organs that are regulated by neural pathways

Question 29

true or false: the autonomic nervous system is always composed of a two neuron chain

Answer 29

yes

Question 30

in the autonomic nervous system, what communicates or innervated the end effector organ?

Answer 30

the second neuron

Question 31

what part of the first neuron (preganglionic neuron) of the autonomic nervous system is in the CNS and which is in the PNS?

Answer 31

- cell body in CNS - axon in PNS

Question 32

in the autonomic nervous system, what do we call the pre and post synaptic neuron instead?

Answer 32

- preganglionic neuron - postganglionic neuron

Question 33

where does the postganglionic neuron sit?

Answer 33

within the ganglion

Question 34

what is a ganglion?

Answer 34

cluster of neuronal cell bodies outside of the CNS

Question 35

each autonomic neural pathway extending from the CNS to an innervated organ is a ____________.

Answer 35

two-neuron chain - preganglionic neuron sits within the CNS, axon projects out towards the peripheral nervous system where it synapses with the second neuron in the ganglia

Question 36

what is the axon of the second neuron in the autonomic nervous system called?

Answer 36

postganglionic fibre

Question 37

what is the axon of the first neuron in the autonomic nervous system called?

Answer 37

preganglionic fibre - it synapses with the cell body of the second neuron in a ganglion

Question 38

what is a varicosity?

Answer 38

- the output zones of our postganglionic neurons - swelling and numerous branching of the axon terminal of the output zone of the postganglionic neuron so that it can release neurotransmitters over very large areas rather than single cells so that you can influence an entire organ rather than one specific cell

Question 39

what region of our body is the sympathetic nervous system?

Answer 39

from the thoracic and lumbar regions of the spinal cord

Question 40

what region of our body is the parasympathetic nervous system?

Answer 40

from the brain and sacral/lower spinal cord

Question 41

are the preganglionic fibres shorter than the postganglionic fibres in the sympathetic nervous system?

Answer 41

preganglionic fibres are shorter than the postganglionic fibres in the sympathetic nervous system

Question 42

what do the preganglionic fibers of the sympathetic nervous system travel into?

Answer 42

the synaptic ganglia chain ('sympathetic trunk') that is located along the side of the spinal cord

Question 43

what does the postganglionic fibres of the sympathetic nervous system innervate?

Answer 43

effector organs

Question 44

are the preganglionic fibres shorter than the postganglionic fibres in the parasympathetic nervous system?

Answer 44

the preganglionic fibres are longer. so long that they will reach a terminal ganglion in or near the effector organ - very short postganglionic fibres ending on cells of an organ itself

Question 45

where is the sympathetic ganglion chain?

Answer 45

next to the spinal cord on both sides

Question 46

most sympathetic preganglionic fibres pass through the sympathetic ganglion chain which extend?

Answer 46

down the thoracic and lumbar region of the spinal cord on both sides

Question 47

do parasympathetic ganglion pass through ganglion near the spinal cord?

Answer 47

no

Question 48

what is the sympathetic ganglion chain used for?

Answer 48

to ensure that the sympathetic system can relay and coordinate signals across the entire thorax

Question 49

what do all your preganglionic neurons utilize to synapse/communicate with our postganglionic neurons?

Answer 49

acetylcholine

Question 50

what differs in the postganglionic neuron from the sympathetic and the parasympathetic nervous system?

Answer 50

- what they secret at the end effector organ

Question 51

what does your parasympathetic system utilize for your postganglionic neuron to communicate with the end effector organ?

Answer 51

acetlycholine

Question 52

what does your sympathetic system utilize for your postganglionic neuron to communicate with the end effector organ?

Answer 52

norepinephrine

Question 53

when would we refer to a fibre as cholinergic fibres?

Answer 53

if it releases acetylcholine

Question 54

when would we refer to a fibre as adrenergic fibres?

Answer 54

if it releases norepinephrine

Question 55

what does the adrenal medulla release?

Answer 55

norepinephrine AND epinephrine

Question 56

what are most organs controlled by?

Answer 56

both sympathetic AND parasympathetic innervations - often they have opposing affects

Question 57

do the parasympathetic and sympathetic systems turn off as one turns on?

Answer 57

no, they are both partially active - although one will show dominance for the overall response

Question 58

which system is your "fight-or-flight"?

Answer 58

sympathetic nervous system

Question 59

what are the advantages of always have both of your autonomic systems parcially active?

Answer 59

- easier/faster to change a systems activity if it is already running - reduces the chances of one system being over-activated when a stimulus is provided