PNS and ANS

Question 1

PNS:
Sensory inputs and motor outputs are categorized as what?
Sensory inputs are also classified as what?

Answer 1

Somatic or visceral

General or special

Question 2

Structural components of the CNS:

• ______ _______ - pick up stimuli
• ______ ______ - axon terminals of motor neurons
• _____ - bundles of peripheral axons
• _____ - clusters of peripheral neuronal cell bodies

Answer 2

sensory neurons
motor endings
nerves
ganglia

Question 3

Draw out the functional organization of the PNS chart.

Answer 3

Refer to notes.

Question 4

How are sensory receptors classified functionally?

Answer 4

By location and by the type of stimulus detected.

Question 5

What do peripheral sensory receptors detect?

Answer 5

Sensory stimuli

Question 6

What are the different location based classifications of peripheral sensory recetpors?

Answer 6

Exteroceptors - stimuli outside the body

Interoceptors - stimuli from internal viscera
(aka visceroceptors)

proprioceptors - monitor degree of stretch

Question 7

Where would exteroceptors be located? What do they detect?

Answer 7

Near or at body surface

Detect touch, pressure, pain, temperature most of special sense organs.

Question 8

Where would interoceptors be located?

What do they detect?

Answer 8

internal viscera

detect temperature, taste, stretching of tissue (stomach)

Question 9

Where would proprioceptors be located?

Answer 9

musculoskeletal organs

Question 10

What are the different subdivisions of the stimulus detected classification of peripheral sensory nerves?

Answer 10

Mechanoreceptors - mechanical force - touch, pressure

Thermoreceptors - temp

Chemoreceptors - chemical composition of blood

Photoreceptors - light

Nociceptors - pain

Question 11

If talking about sensory receptors that detects stretch in the stomach, what is it called?

Answer 11

Interoceptor mechanoreceptor

have to use both classifications

Question 12

How are spinal nerves named?

How many pairs are there?

Answer 12

For point of issue from the spinal cord:
ex: cervical nerves (c1-C8)
31

Question 13

What is a plexus?

Answer 13

Bundle of nerves

Question 14

What are enlargements?

Answer 14

Nerve groups that supply the limbs (cervical and lumbar)

Question 15

Spinal nerve arrangement:

• Spinal nerves arise from the spinal cord as a series of small ______
• These converge to form the ______ and ______ roots
• the roots join to form a mixed nerve called the _____ ______ _____
• this branches into the ______ ______ and ______ ______

Answer 15

rootlets
dorsal and ventral root
spinal nerve trunk
dorsal ramus and ventral ramus

Question 16

What does the dorsal root contain?
The ventral root?
What do both the dorsal and ventral ramus contain?

Answer 16

Dorsal root - incoming sensory nerve fibres
Ventral root - outgoing motor nerve fibres

Ramus
- contains sensory and motor nerve fibres

Question 17

Why is it a dorsal root ganglion? (i.e. why not ventral)

Answer 17

Unipolar is sensory - so cell bodies are in the PNS

Multipolar for motor - dendrites close to cell body, located in CNS

Question 18

ANS controls ______ _____ functions

Answer 18

visceral motor

Question 19

The ANS regulates ______ visceral functions (visceral motor division) such as what?
What does it innervate?

Answer 19

unsconscious
- heart rate, digestion, blood pressure, urination
Glands, smooth muscle and cardiac muscle

Question 20

Give the chart from PNS onwards.

Answer 20

PNS

• Sensory
• • somatic
• • visceral
• Motor
• • somatic
• • visceral = ANS
• – Sympa
• – Parasympa

Question 21

Comparison of motor systems:

Somatic vs. autonomic.

Answer 21

Somatic motor

• one motor neuron* from CNS to skeletal muscle
• conscious*
• axons well myelinated*, conduct impulses rapidly

Autonomic
- two motor neurons*
– preganglionic in brain or spinal cord and,
– postganglionic
(pre and post)
Conduction is slower due to:
- thinly myelinated or unmyelinated axons*
- motor neurons synapse in a ganglion (two synapses*, slows down impulse conduction)

Question 22

In the sympathetic nervous system, what can the preganglionic fibres synapse on?

Answer 22

Postganglionic fibre or adrenal medulla

Question 23

What are the two divisions of the ANS?

Answer 23

Mostly innervate same structures but opposite functions:
Sympathetic - fight or flight
Parasympathetic - rest and digest

Question 24

Describe some responses to dangerous or exciting situations from the sympathetic system.

Answer 24

Widening of pupils, cold skin, sweating, inhibition of non-essential functions.

Question 25

Which organs have only sympathetic stimulation?

Answer 25

sweat glands, adrenal medulla, arrector pili and blood vessels.

Question 26

What are the housekeeping activities of the parasympathetic division?

Answer 26

SLUDD - Salivation - Lacrimation - Urination - Digestion - Defecation

Question 27

Which dominates, sympathetic or parasympathetic?

Answer 27

Para

Question 28

Why do we get a lump in our throat when crying?

Answer 28

As a result of stress, trigger sympathetic, tries to circulate more air while triggering lacrimation - as starting to cry, breathe faster but, tears and mucus make us swallow more but the muscles are constricted here, causing a lump in our throat.

Question 29

Parasympathetic will ____ the size of the pupil, sympathetic will _______ it.

Answer 29

decrease | increase

Question 30

What are the anatomical differences between the sympathetic and parasympathetic.

Answer 30

1 - Arise from different regions of the CNS - - S - thoracolumbar - - P - craniosacral 2 - Length of postganglionic neurons - S - long - P - short 3 - Branching of axons - S - highly branched (many organs) - P - few branches (localized effect)

Question 31

Role of the adrenal medulla: - major organ of the _______ nervous system - constitutes largest sympathetic ______ - secretes both _______ and _______

Answer 31

sympathetic ganglia norepineprhine and epineprhine

Question 32

Describe the differences between innervation by the sympathetic and parasympathetic on the following structures: - eye - systemic blood vessels - heart - stomach, SI, LI - ureter + bladder

Answer 32

Eye - S - pupil dilates - P - pupil constricted Systemic blood vessels - only sympathetic stimulation Heart - S - increase HR - P - return HR to normal Stomach, SI, LI S - inhibit peristalsis, absorption and secretion P - increased absorption, secretion and peristalsis Ureter and bladder S - inhibit detrusor muscle contraction + contraction of external urethral sphincter P - contract detrusor, inhibit contraction of external urethral sphincter

Question 33

What do general visceral sensory neurons monitor?

Answer 33

Stretch, temperature, chemical changes and irritation

Question 34

Where are the cell bodies of visceral sensory neurons located?

Answer 34

Dorsal root ganglion

Question 35

Where is the visceral sensory cortex located?

Answer 35

Insula

Question 36

What sensory input does the insula receive?

Answer 36

General sensory input from thoracic and abdominal viscera | and gustation via thalamus

Question 37

Which sense does not go to the insula?

Answer 37

Olfaction, sent to temporal lobe instead

Question 38

Any incoming sensory information goes through what first? | What is the exception?

Answer 38

thalamus | olfaction

Question 39

Visceral pain - ___ pain results when visceral organs are cut - _____ to localize - visceral paint results from _____ irritation, _______ or spasms - Visceral pain is often perceived to be of _____ origin - this is called _______ pain

Answer 39

no hard chemical irritation, spasms, inflammation somatic origin for visceral pain = referred pain

Question 40

What is an example of referred pain?

Answer 40

Heart attack - feel in left limb or lower jaw - either cuz sensory fibres and motor fibres enter/exit same place or vasoconstriction of vessels supplying somatic region

Question 41

Draw out the diagram with the different PNS divisions and cortexes of each.

Answer 41

Refer to notes