Quiz #1: PNS (4) Flashcards

(65 cards)

1
Q

____________ and ______________ stimuli go to the afferent division of the PNS, which then inputs into the CNS.

A
  1. Sensory
  2. Visceral
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2
Q

What are the two divisions of the Efferent division?

A
  1. Somatic NS
  2. Autonomic NS
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2
Q

Output from the CNS to the periphery through the __________ division.

A

Efferent

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3
Q

What are the three parts of the autonomic nervous system?

A
  1. sympathetic
  2. parasympathetic
  3. enteric
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4
Q

What does the sympathetic and parasympathetic nervous system go to?

A

smooth muscle
cardiac muscle
exocrine glands
endocrine glands

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4
Q

What does the somatic nervous system go to?

A

somatic nervous system –> motor neurons –> skeletal muscles

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5
Q

What is a sensory receptor?

A

a SPECIALIZED STRUCTURE that responds to a stimulus in the external (sensory) or internal (visceral) environment of an organism

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6
Q

What is a specialized ending?

A

ending of the afferent (towards the CNS) neuron

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7
Q

What are some types of sensory receptor structures?

A
  1. specialized ending
  2. specialized cell
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8
Q

What are the types of specialized endings of the afferent neuron?

A
  1. free nerve endings
  2. encapsulated nerve endings
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8
Q

Encapsulated nerve endings have what around them?

A

a connective tissue capsule

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9
Q

What are the two different ways a sensory receptor responds to a stimulus?

A
  1. detection of sensory stimuli
  2. transduction of sensory stimuli into electrical signals: receptor potentials
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9
Q

What are specialized cells associated with?

A

the peripheral ending of the afferent neuron
Ex. sensory organ

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10
Q

What does the phrase “it is relatively insensitve to other types of stimuli” mean exactly?

A

sensory receptors usually respond to a specific type of stimulus
HOWEVER, if a type of stimulus is very STRONG, will activate other receptors that may not be activated by it under normal circumstances

Ex. a punch to the face = touch receptors BUT if you are hit hard enough, you “see stars” aka receptors for sight

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11
Q

What is an interoceptor?

A

stretch, pressure, pain

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11
Q

What are the different sensory receptors in terms of environment?

A
  1. exteroceptor
  2. interoceptor
  3. proprioceptor
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11
Q

What is an exteroceptor?

A

sensory receptor for vision, hearing, taste, smell, touch, heat, cold, pain

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12
Q

What are the traits of a stimulus?

A
  1. each receptor cell is designed to respond sensitively to a specific type of stimulus aka an ADEQUATE STIMULUS
  2. It is relatively insensitive to other types of stimuli
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13
Q

What are the types of sensory receptors (7)?

A
  1. Photoreceptors
  2. Mechanoreceptors
  3. Chemoreceptors
  4. Thermoreceptors
  5. Osmoreceptors
  6. Nociceptors (pain)
  7. Others (itchy, magnetoception, etc)
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14
Q

What is a proprioceptor?

A

sense the relative position and movements of the body parts
Often found in muscles, tendon, joint capsules

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15
Q

TRUE OR FALSE

Sensory receptors are only found in humans and other animals.

A

FALSE
plants have it as well
ex. when you touch a fern, it may fold in on itself = reacting to your touch

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16
Q

Sensory receptors are ______________, NOT voltage or transmitter sensitive

A

stimulus sensitive

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17
Q

What is the pathway from stimulus to action potential?

A
  1. stimulus
  2. sensory receptor
  3. receptor potential
  4. action potential
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17
Q

What is a compound sensation?

A

sensation that activates more than one sensory receptor

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18
What is the function of sensory receptors?
1. energy form (modality) - heat/ light/ sound/ pressure/ chemical changes 2. quality - color/ pitch/ sweet/ sour/ fragrant / putrid 3. intensity - brightness/ loudness/ how sweet/ how smelly 4. location - where is the sensation coming from? where on surface of body is the touch?
19
Receptor potential is caused by Na+ influx induced ______________.
Depolarization EXCEPTION: photoreceptors (hyperpolarized)
20
What does Na+ ions entering the SPECIALIZED ENDING of the afferent neuron from the stimulus result in?
receptor potential
21
Once the SPECIALIZED ENDING is depolarized, the adjacent region opens __________.
voltage-gated Na+ channels
21
What does Na+ ions entering the RECEPTOR CELL of the afferent neuron from the stimulus result in?
Receptor potential
21
What happens after the stimulus occurs in specialized ENDINGS of afferent neurons?
stimulus opens stimulus sensitive channels, allowing Na+ entry
22
What happens after the stimulus occurs in specialized CELLS closely associated with the peripheral ending of the neurons?
stimulus acts upon separate receptor cell and opens stimulus-sensitive channels, allowing Na+ entry
22
Neurotransmitter released by a receptor cell opens chemically gated receptor-channels at the afferent ending, permitting net ________ (ion) entry. This results in what?
Na+ results in depolarization that opens voltage-gated Na+ channels in adjacent reegion
22
What does Na+ entry from voltage gated Na+ channels result in in a SPECIALIZED ENDING?
action potential in afferent fiber that will self-propagate to CNS
23
Local depolarization of the receptor cell results in the opening of _______________.
voltage gated Ca2+ channels
24
Ca2+ entry into the receptor cell triggers _________________.
exocytosis of neurotransmitter
25
What does Na+ entry from voltage gated Na+ channels result in in a receptor CELL?
Initiates action potential in afferent fiber that self-propagates to CNS
26
What is the regulation of a receptor potential?
Receptor potential is GRADED
27
What does it mean for a receptor potential to be graded
graded according to stimulus intensity NOT all-or-none Ex. if stimulus is strong, receptor potential will be strong SYNONYMOUS TO pressing gas pedal down in car = the more you push the faster you go/the less you push the less fast you go
28
A graded receptor potential has ____ (Y/N) refractory period.
No
29
What is saturation of a receptor potential?
in the end, still a receptor if there is over saturation of the receptor, there is a MAXIMUM receptor potential
30
What is the receptor potential a summation of?
TEMPORAL (a stimulus is repeatedly applied at a constant intensity, causing an increase in the response) SPATIAL (physiological process that occurs when multiple stimuli are applied to different areas of a neuron at the same time, using multiple synapses = cumulative effect) recruitment of more receptors
31
TRUE OR FALSE An action potential is all-or-none
TRUE therefore, the higher the receptor potential, the higher the FREQUENCY of the action potential
32
What is the dynamic range of a sensory receptor?
range of stimulus intensities over which the receptor is sensitive to intensity gradations WILL EVENTUALLY PLATEAU OUT
33
Action potential ____________ is related to size of the ____________ potential.
1. frequency 2. receptor
33
Compare the main difference between graded potentials and all-or-nothing potentials
GRADED: intensity depends on the intensity of the stimulus that causes it ALL-OR-NOTHING: the stronger the stimulus the higher the frequency of the action potential = needs to meet threshold
34
Maximum action potential frequency is determined by what?
the absolute refractory period
35
In the excitability curve, when would even the strongest stimuli never result in a reaction?
absolute refractory period
36
During the period after the absolute refractory period (early on in the relative refractory period), how many Na channels are available?
A few
37
During the absolute refractory period, how many functional Na channels are working?
NONE
38
During the period after the absolute refractory period (later on in the relative refractory period), how many Na channels are available?
Many
39
A small receptor potential will result in a ___________ action potential frequency.
lower
39
When are all Na channels recovered on an excitability curve?
when back to resting potential latest in the relative refractory period
40
A large receptor potential will result in a higher action potential __________.
frequency
41
What is the labeled line principle?
Each incoming neuron terminates at a specific place in the brain
41
When the receptive field on the periphery of the body is small, the discrimination is ________________ (easier/harder)?
easier
42
What is the somatosensory cortex?
part of the brain's cerebral cortex that receives sensory information from the body, processes it, and helps us make decisions
43
What type of sensory information does the somatosensory cortex receive?
1. somesthetic sensation (body feelings) 2. touch 3. pressure 4. stretch 5. vibration 6. pain
44
What is the somesthetic map?
Map that states that each cell in cortex receives afferent input via a labeled line coming from a touch receptor at a specific location on the periphery of body
45
The ____________ (larger/smaller) the area at the somatosensory cortex, the _____________ (more/less) sensory neurons at the corresponding region.
larger/more smaller/less
46
What is a reflex?
any response that occurs automatically without conscious effort
47
What are the two types of reflexes?
1. simple/basic 2. acquired/conditioned
48
What is the reflex arc?
the neural pathway involved in accomplishing reflex activity
49
What is the pathway of the reflex arc?
1. sensory receptor 2. afferent pathway 3. integrating center (gray matter of spinal cord/brainstem) 4. efferent pathway 5. effector **DOES NOT INVOLVE THE BRAIN**
50
What is the withdrawal reflex?
involuntary response of the spinal cord that protects the body from harmful stimuli
51
Withdrawal reflex pathway summary?
1. stimulus activates pain receptor in finger 2. action potential generated in AFFERENT pathway which propagates impulses to spinal cord 3. spinal cord = integrating center where afferent neuron stimulates excitatory interneurons + inhibitory interneurons + interneurons (to ascending pathway to brain) 4. efferent pathway stimulates biceps to contract and another leads to relaxation of tricep 5. flexion of elbow joint pulls hand away from painful stimulus (response completes the withdrawal arc) 6. events that occur in brain on arrival of signal via ascending pathway (brain finally processes what happened)