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Neurophysiology > Unit 1 > Flashcards

Unit 1 Flashcards

1
Q

In _______ _______, the separation of charge across a membrane that would develop if the membrane were permeable to only one ion

A

Equilibrium (Nernst) potential

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2
Q

________ ______, the separation of charge across a membrane that develops in excitable cells that are permeable to MORE than one ion

A

Resting membrane potential

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3
Q

_______ _____, the local change in RMP that results from either an excitatory or inhibitory stimulus

A

local (receptor) potential

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4
Q

_____ ______, the propagation along the axon of a potential resulting from a threshold stimulus. Threshold may be reached by the summation of local potentials and is ALL-OR -NONE

A

Action potential

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5
Q

The equillibrium potential for a particular ion can calculated using ________

A

Nernst equation

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6
Q

The resting membrane potential in most large nerve fibers based on the factors in the Goldman equation is about _______ mV but with the Na/K pump the RMP in large neurons reaches _____mV

A
  • 86mV

- 90mV

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7
Q

What contributes to the negativity of the interior of the cell

A

Na/K pump

3 Na out, 2 K in

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8
Q

The majority of the intracellular fluid and extracellular fluid is _________(charge)

A

Electrically neutral

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9
Q

Where does the resting membrane potential exist?

A

Only immediately inside and outside the cell membrane

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10
Q

What ion channels are responsible for the RMP?

A

K+ leak channels

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11
Q

K+ leak channels are permeable to what ions?

A

K+ and Na

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12
Q

What does the Goldman-Hodgkin-Katz equation address? 3 things

A

1) Concentration of ions inside and outside the cell
2) Permeability of the membrane to the ions
3) Valance of the ions (+ or -)

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13
Q

________ are always open, therefore sets up the baseline permeability of the membrane

A

K+ leak channels

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14
Q

What are examples of ion channels that are involved in maintaining the RMP?

A

K+ leak channels (main cause)

Na/K pump (necessary for maintenance and restoration

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15
Q

_________ is when potential becomes more negative

A

Hyperpolarization

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16
Q

What is hyperpolarization caused by?

A

Increasing permeability of the membrane to Cl- or K+

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17
Q

________ is when membrane potential becomes less negative

A

Depolarization

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18
Q

Describe local potentials

A

Local potentials are either depolarization or hyperolarization events that occur where stimuli are applied to an excitable cell

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19
Q

What are examples of stimuli

A

Synapse/neurotransmitter
Hormone or other chemical
Mechanical ( pressure, temperature, etc.)
Artificial (stimulating electrode)
Stimulus depends on what the excitable cell is sensitive to

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20
Q

A small stimulus causes a ______ depolarization of the cell membrane
A larger stimulus causes ______ depolarization
A stimulus of longer durations causes ______ depolarization but not of any greater ______ than the previous one

A

Small;
More;
Longer lasting; not of any greater strength

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21
Q

Local membrane potentials are _______. (The size of the stimulus is proportionate to the magnitude of the potential change)

A

Graded

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22
Q

What are local membrane potentials caused by?

A

Ligand-gated or mechanically gated ion channels

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23
Q

Do effects of local membrane potentials propagate far from the site of stimulus?

A

No they do not propagate

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24
Q

If a logical membrane potential meets or exceed __________ then an AP results

A

Threshold

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25
Q

AP are _________. They occur completely or not at all

A

All-or-none

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26
Q

What are the phases of the action potential?

A

Depolarization phase
Depolarization phase
Afterpotential/ hyperpolarization/ undershoot

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27
Q

Describe the depolarization phase

A

A threshold stimulus activates voltage-gated sodium channels

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28
Q

Threshold in the depolarization phase is usually ________mV above RMP

A

15-30 mV

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29
Q

During the depolarization phase, Na+ permeability therefore ________; Na+ _______ the cell causing depolarization

A

Increases; enters

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30
Q

Describe the repolarization phase

A

Voltage gated Na+ channels inactivate

Voltage gated K+ channels open increasing K+ permeability; therefore K+ leaves the cell causing repolarization

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31
Q

In the repolarization phase, voltage gated _____ channels open increasing _____ permeability; therefore ___ leaves the cell causes repolarization

A

K+, K+ and K+

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32
Q

Depolarization involves activation of the _____ voltage gated channels opening
Repolarization involves _____ voltage gated channels opening

A

Depolarization- Na+

Repolarization- K+

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33
Q

What is the Afterpotential/ hyperpolarization/ undershoot?

A

Transient hyperpolarization that occurs due to late closing of Voltage gated K+ channels

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34
Q

What is involved in restoring RMP?

A

Na/K pump

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35
Q

What are the 3 states of the V-gated Na+ channel?

A

Resting (closed)
Activated
Inactivated

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36
Q

What are the two states of the V-gated K+ channels?

A

Resting (closed)

Activated (opened)

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37
Q

The opening of voltage-gated channels increase _______ of the ions

A

Conductance

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38
Q

Describe an absolute refractory period

A

No stimulus no matter how strong can initiate another action potential

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39
Q

Describe a relative refractory period

A

A greater than threshold stimulus is required to initiate another AP

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40
Q

What are the differences between AP and local potentials?

A

AP- propagate and dont dissipate over long distances

Local potentials do not propagate and dissipate over a short distance

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41
Q

What prevents retrograde conduction of the AP?

A

The refractory period

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42
Q

If an axon is ARTIFICIALLY stimulated in the middle of an axon, Action potentials propagate _____

A

Bidirectionally

Both directions

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43
Q

What are the conditions that require propagation?

A

Reaching threshold

Adequate numbers of funcitonal voltage gated channels

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44
Q

Describe the fibers of a typical nerve

A

There is a mixture of myelinated and unmyelinated nerve fibers

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45
Q

________ nerve fibers tend to be larger

A

Myelinated

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46
Q

________ nerve fibers are more numerous (2X more)

A

Unmyelinated

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47
Q

In myelinated axons in the PNS are myelinated via ______ and in the CNS by _____

A

Schwann cells -PNS

Oligodendrocytes -CNS

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48
Q

In UNmyelinated axons, ________ supports but doesnt myelinated these axons

A

Schwann cells

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49
Q

Schwann cell membrane contain the lipid ________ which is an excellent insulator which decreases ion flow by 5000X

A

Sphingomyelin

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50
Q

_______ increases the velocity of nerve transmission and conserves energy of the nerve

A

Saltatory conduction

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51
Q

During satlatory conduction, where does inflow through the membrane occur?

A

Only at the nodes of Ranvier

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52
Q

what increases conduction velocity of an AP?

A

Myelination

Increase in axon diameter

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53
Q

What does the PNS consist of?

A

12 pairs of cranial nerves

31 pairs of spinal nerves

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54
Q

_________ detect specific types of stimuli (light in the eyes, tactile in the body surface, etc.)

A

Sensory receptors

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55
Q

Muscles and glands are referred to as ______

A

Effectors

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56
Q

What do chemical synapses involve the release of?

A

The release of neurotransmitters into a synaptic cleft and postsynaptic receptors to respond to those NT leading to a change in membrane potential

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57
Q

How do electrical synapses work?

A

Use gap junctions to directly propagate action potentials to the post-synaptic cleft

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58
Q

_______ synapses secret NT to effect the post synaptic cell (excitatory, inhibitory, modify sensitivity)

A

Chemical synapses

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59
Q

______ synapses are unidirectional from presynaptic -> post synaptic membranes

A

Chemical

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60
Q

______ synapses are most often used in smooth muscle and cardiac muscle

A

Electrical synapses

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61
Q

How are electrical synapses connected?

A

Gap junctions

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62
Q

How do electrical synapses work?

A

Free movement of ions from one cell to another; bidirectional transmission

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63
Q

What type of receptor proteins are involved in direct neurotransmitter actions?

A

Ionotropic

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64
Q

What type of receptor proteins are involved in indirect neurotransmitter action?

A

Metabotropic receptors

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65
Q

Ionotropic receptors are ________ ion channels

A

Ligand gated

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66
Q

Ionotropic receptors effects are ___________ (longevity)

A

Short lived

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67
Q

Ionotropic receptors are ligand gated ion channels are can be ______ channels or ______ channels

A

Cation or anion channels

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68
Q

Na+ channels are ______ (excitatory or inhibitory). When open they tend to ______

A

Excitatory

When open tend to depolarize

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69
Q

K+ channels and Cl- channels are ______ (excitatory or inhibitory). When they are open they tend to _______

A

Inhibitory

When open tend to hyperpolarize and are therefore inhibitory

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70
Q

Metabotropic receptors by the use of _________ have more prolonged effects

A

G-proteins

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71
Q

Where are NT made?

A

In the cytosol of the presynaptic terminal and are actively transported into vesicles until released

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72
Q

What are the effects of NT’s?

A

Most often the effect is to increase or decrease conductance through ion channels

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73
Q

How are NT removed from the synaptic cleft?

A

Enzymatic destruction
Reuptake
Diffusion

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74
Q

Who secretes the NT Acetylcholine (Ach)?

A

Large pyramidal cells
Basal ganglia cells
Motor neurons to skeletal muscle
Many autonomic neurons

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75
Q

What is the effect of Ach?

A

Excitatory in most cases

Inhibitory in the heart and other parasympathetic targets

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76
Q

Who secretes norepinephrine (noradrenaline)?

A

Neurons in the brain stem and hypothalamus (locus ceruleus)

Most post gnaglionic neurons of the sympathetic NS

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77
Q

What is the effect of norepinephrine?

A

Excitatory or inhibitory depending on receptor/ target tissue

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78
Q

secretes dopamine and what is its effect?

A

Substantia nigra

Usually inhibition

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79
Q

Who secretes Glycine and what’s it effect?

A

Spinal cord neurons

Always inhibitory

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80
Q

Who secretes GABA and what’s it effect?

A

Nerve endings in the spinal cord, cerebellum, basal ganglia, and cerebral cortex

Effect: always inhibitory

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81
Q

Who secretes glutamate and what’s its effect?

A

Neurons in sensory pathways

Effect: always excitatory

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82
Q

Who secretes serotonin and what’s its effect?

A

Certain brain stem neurons

Effects- inhibitor (effects pain pathways, mood and sleep)

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83
Q

Who secretes NO?

A

Areas of the brain involved in memory and behavior

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84
Q

How is NO a unique NT?

A

It is not stored in vesicles but made as needed and has more of a metabolic function

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85
Q

What are the effects of NO?

A

Modifies neuronal excitability for seconds to minutes

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86
Q

______ are synthesized by ribosomes in the neuronal cell body, processed by the ER and golgi then packaged into transmitter vesicles

A

Neuropeptides

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87
Q

How are neuropeptide vesicles transported in the neuron?

A

By axonal streaming

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88
Q

_______ are very potent, small quantities are released at a time

A

Neuropeptides

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89
Q

A typical spinal cord neuron is _________ and have a RMP of ______ mV

A

Multipolar

-65mV

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90
Q

T/F: the resting membrane potential of neurons exists throughout the membrane, including the soma

A

True

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91
Q

The ______ has highly conductive intracellular fluid and has a large diameter.

A

Soma

Therefore any change in one part of the soma is spread quickly to the rest of the soma

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92
Q

What are two examples of local membrane potentials?

A

EPSP ( excitatory postsynaptic potential)

IPSP (inhibitory postsynaptic potential)

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93
Q

In EPSP’s what ion channels are involved?

A

Na+ channels

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94
Q

In IPSP’s what ion channels are involved

A

Cl- and K+

Both of these lead to hyperpolarization of the membrane therefore more inhibitory

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95
Q

Axon potentials are generated in the ______ when the RMP rises above _______

A

Initial segment ( axon hillock)

Threshold

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96
Q

The initial segment has a high density of __________ channels

A

Voltage gated sodium channels

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97
Q

T/F: A single EPSP from a single neuron is rarely big enough to hit a threshold

A

True

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98
Q

What are two ways in which threshold can be reached?

A

Spatial summation

Temporal summation

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99
Q

_________ summation, many presynaptic terminals stimulating APSP’s at the same time can summate to reach the threshold for firing

A

Spatial summation

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100
Q

_______ summation successive discharges of a single presynaptic terminal can also summate to reach threshold

A

Temporal

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101
Q

_______ summation of EPSPs and IPSPs May completely or in part cancel each other out

A

Simultaneous

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102
Q

________ is when a neurons presynaptic potential’s have summate toward threshold but has not heat reached it

A

Facilitation

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103
Q

80-95% of all presynaptic terminals end on ______ and the rest on ______

A

Dendrites; soma

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104
Q

Most dendrites cannot transmit AP bc they lack _________, therefore their threshold is ______

A

Enough voltage gated channels,

too high

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105
Q

_________ is the loss of excitability after experiencing a high frequency of firing for a period of time

A

Synaptic fatigue

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106
Q

Synaptic fatigue can also be due to ________ ______ _____ in the presynaptic terminals

A

Exhaustion of stores of NT

107
Q

What are other possible causes of synaptic fatigue?

A

Progressive inactivation of postsynaptic receptors
Or
Development of abnormal concentrations of ions inside the postsynaptic cell

108
Q

_________ may be a protective mechanism against excessive neuronal activity ( probably why seizures finally end)

A

Synaptic fatigue

109
Q

What are the following’s effects on synaptic activity:

  • acidosis
  • alkalosis
  • hypoxia
  • drugs
A

Acidosis- depresses neuronal activity
Alkalosis- increases neuronal activity
Hypoxia- even for a few seconds can STOP nerve transmission in some neurons
Drugs - can be excitatory or inhibitory

110
Q

What are the 3 steps common to all senses?

A

Physical stimulus
Set of events converts the stimulus into an AP
Response to the AP

111
Q

What are the 5 ways sensory information is used?

A

Perception
Control of movement regulation of internal organs
Maintenance of arousal
Memory

112
Q

Each sensation detected by sensory receptors is called a ________

A

Modality

113
Q

What are examples of modality?

A

Pain, touch, cold, sound

114
Q

Describe the labeled line principle

A

All sensory neurons transmit AP

The CNS differentiated different modalities based on cortical location of the tract termination

115
Q

How does the CNS differentiate different modalities (sensations)?

A

Based on cortical location of the tract termination

116
Q

Classification of the receptors can be based on location of stimulus. And the 2 are ________ and ______

A

Interoreceptor

Exteroreceptor

117
Q

Classification of receptors can be based on structure. Three examples are

A

Simple
Encapsulated
Receptor cell associated

118
Q

Classification of sensory receptors can be based on modality. What are the 5 examples?

A 
Mechanoreceptors 
Thermoreceptors 
Nociceptors 
Electromagnetic receptors 
Chemoreceptors
119
Q

________ receptors respond to mechanical pressure or distortion

A

Mechanoreceptors

120
Q

______ receptors respond to heat or cold

A

Thermoreceptors

121
Q

_________ receptors respond to noxious (painful) stimuli

A

Nociceptors

122
Q

_________ receptors respond to photons (sight)

A

Electromagnetic receptors

123
Q

________ receptors respond to chemical stimuli

A

Chemoreceptors

124
Q

What are examples of cutaneous Mechanoreceptors in the epidermis and dermis

A 
Meissners corpuscle 
Merkels receptor 
Ruffini’s corpuscle 
Pacinian corpuscle 
Hair receptor
Free nerve endings
125
Q

________ receptors are neurons with free nerve endings

A

Simple receptors

126
Q

_______ receptors have nerve endings enclosed in connective tissue capsules

A

Encapsulated (complexes neural)

127
Q

_________ are cells that release NT onto sensory neurons, initiating an AP/

A

Receptor cell associated (most special senses receptors)

128
Q

What are examples of deep tissue mechanoreceptor types?

A

Muscle spindles

Golgi tendon organs

129
Q

What are examples of special senses mechanoreceptor types

A

Hair cells (cochlea, vestibular apparatus)

130
Q

What are the locations of the following chemoreceptor modalities?

  • taste
  • smell
  • arterial oxygen
  • osmolality
  • blood CO2
  • blood glucose, amino acids, FA’s
A

Taste- taste buds
Smell- olfactory cells
Arterial oxygen- Aortic and carotid bodies
Osmolality- neurons in supraoptic nuclei
Blood CO2- aortic and carotid bodies, medulla
Blood glucose, amino acids, fatty acids - hypothalamus

131
Q

What are examples of chemoreceptors? (6)

A 
Taste 
Smell
Arterial oxygen
Osmolality 
Blood CO2
Blood glucose, aminoacids and FA’s
132
Q

What are examples of thermoreceptors, cold and heat receptors?

A

Free nerve endings

133
Q

What are examples of electromagnetic receptors?

A

Vision - rods and cones

134
Q

Nociceptors are _____ receptors

A

Pain

135
Q

T/F: pain receptors are a strange modality in that more than one type of stimulus can elicit pain

A

True

136
Q

Nociceptors (pain receptors) are called _______ because more than one type of stimulus can elicit pain

A

Polymodal

137
Q

What are 3 examples of stimuli that can elicit pain through nociceptors?

A

Chemical
Temperature
Mechanical

138
Q

Local potentials in sensory endings are called _________

A

Receptor potentials

139
Q

Mechanical deformation and chemical binding of a stimulus ________

A

Opens ion channel

140
Q

Temperature alters ______ when responding to a specific modality

A

Permeability to ions

141
Q

Light directly or indirectly leads to ________ when responding to a specific modality

A

Ion flow

142
Q

The greater the sustained stimulus strength, the _____ the AP frequency

A

Greater

143
Q

Local membrane potentials or receptor membrane potentials in sensory endings are ______

A

Graded

144
Q

The greater the frequency of the AP, means more _______ release

A

NT release

145
Q

A weak stimulus releases ______ NT

A strong stimulus causes more AP and releases _____ NT

A

Little NT

More NT

146
Q

The stimulus intensity is equivalent in both the ______ and _______ adapting neurons

A

Rapidly and slowly

147
Q

In _____ adapting neurons, the frequency of firing decreases quickly

A

Rapidly adapting (phasic receptors)

148
Q

Rapid adaptation = ______ receptors

Slow adaptation = ________ receptors

A

Phasic receptors

Tonic receptors

149
Q

Why are rapidly adapting (phasic) receptors important?

A

Bc they punctuate our sensory experience by highlighting stimuli that changes (input of new stimuli)

150
Q

Sensory adaptation is useful in ______ and _____ cases

A

Smell and temperature

151
Q

________ are cutaneous mechanorecptors that sense tickle, itch, and pain. Their adaptation rates are tonic or phasic

A

Free nerve endings

152
Q

_______ are cutaneous mechanoreceptors sense stretching of skin and deep pressure. Their adaptation rate is tonic

A

Ruffini endings

153
Q

______ are cutaneous mechanoreceptors that sense fine touch and pressure. Their adaptation rate is tonic

A

Merkel discs

154
Q

________ are cutaneous mechanoreceptors that sense fine touch, pressure and slow vibration. Their adaptation rate is phasic- moderate.

A

Meissners corpuscle

155
Q

________ is a cutaneous mechanoreceptor that sense crude touch, and movement of hair. It’s adaptation rate is ______

A

Hair follicle

Phasic -moderate

156
Q

_____ are cutaneous mechanorecptor4s that sense fast vibration. Their adaptation rate is phasic -fast

A

Krause bulbs

157
Q

________ are cutaneous Mechanoreceptors that sense pressure, fast vibration and tickling. Their adaptation is phasic -fastest

A

Pacinian corpuscle

158
Q

Describe the predictive value of phasic receptors

A

If a receptor detects the rate of change of a sensory input, it can predict the status of the stimulus in the future
Ex: semincirular canals sense head rotation. Can predict where the head will be in the next few seconds so that balance can be maintained

159
Q

What is the function of fiber type Aalpha? Is it fast or slow?

A

Proprioception; somatic motor

Fastest bc thickest myelination and axon of diameter is large

160
Q

What are the functions of fiber type Abeta?

A

Proprioception, touch, pressure

161
Q

What are the functions of fiber type Agamma

A

Motor to muscle spindles

162
Q

What are the functions of fiber type Adelta?

A

Fast pain, cold, touch

Less fast than gamma, beta and alpha

163
Q

What is the function of fiber type B?

A

Preganglionic autonomic

164
Q

What are the functions of C type fibers?

A

Slow pain, temperature, some mechanoreceptors, postganglionic sympathetic

165
Q

For the functions of proprioception: muscle spindle (annulospiral ending), what are the general and numerical classification of those sensory nerves?

A

General: Aalpha
Number: 1a

166
Q

Sensory classification sometimes used for sensory neurons is a ______ classification

A 
Numerical classification 
(Ia, Ib, II, III, IV)
167
Q

What is a numerical and general sensory classification for the neurons that functions in proprioception in the Golgi tendon organ?

A

Ib- numerical

Aalpha- general

168
Q

What is a numerical and general sensory classification for the neurons that functions in proprioception: muscle shingle (flower-spray ending), fine touch, pressure?

A

II-numerical

Abeta - general

169
Q

What is a numerical and general sensory classification for the neurons that functions in pain and cold, crude touch?

A

III- numerical

Adelta - general

170
Q

What is a numerical and general sensory classification for the neurons that functions in pain, temperature, itch crude touch?

A

IV - numerical

C- general

171
Q

_______ is the area of skin a neurons dendritic zone is sensitive to

A

Receptive field

172
Q

The bigger the _________, the harder it is to pinpoint the location of a stimulus

A

Receptive field

173
Q

Describe spatial summation of receptive fields

A

Overlapping receptive fields of neighboring neurons are “recruited” with stronger stimuli

174
Q

Describe temporal summation of signals in nerve tracts

A

Increased frequency of nerve impulses in fiber resulting from stronger stimuli

175
Q

What is the spatial and temporal summation effect on the CNS

A

A strong stimulus will excited neurons to fire with high frequency and will recruit fibers innervating neighboring receptive fields

176
Q

What is a neuronal pool/ circuit/ pathway?

A

A collection of communicating neurons, large or small

177
Q

Neuronal pools interconnect in a variety of ways to process ________ and create ______

A

Process incoming sensory input

Create patterns of output

178
Q

Divergence of stimuli can occur in _______ or _______

A

In the same pathway
Or
Multiple tracts

179
Q

In _____, input neurons can be originating form the same tract or diffent tracts of the NS and end up on one neuron.

A

Convergence

180
Q

In _________ Circuit one mechanism by which input signals can be prolonged.

A

Reverberating (oscillatory) circuit

181
Q

Reverberating (oscillatory) circuits can be stoped by _______ or _______

A

Incoming inhibitory signals
Or
Synaptic fatigue

182
Q

Reverberating circuits may be sped up by _______

A

Facilitation (excitatory signals)

183
Q

_______ is another mechanisms by which a signal can be prolonged. When long-acting neuropeptides are used, the postsynaptic neuron May continue for many milliseconds after the input neuron fired

A

Synaptic after- discharge

184
Q

________ refer to the sensations that are common throughout the body. They are also referred to as _____

A

Somatic sensations

General senses

185
Q

______ are tactile touch receptors located in the epidermis and corneal epithelium. Their modality is crude touch,pressure, tickle and itch

A

Free nerve endings

186
Q

What is the location of free nerve endings and their modalities?

A

Location: everywhere in the epidermis and corneal epithelium
Modality: crude touch, pressure, tickle, itch

187
Q

________ are uncapsulated and have no complex sensory structures

A

Free nerve ending

188
Q

_______ are the most common type os nerve endings and have a varying degree of adaptation

A

Free nerve ending tactile receptors

189
Q

what are the fiber types of free nerve endings?

A

Adelta or C

190
Q

What is the location and modalities of Meissners corpuscles?

A

Location: glabrous (non-hairy like on palms or soles) skin, the dermis and particularly dense areas that have the keenest sense of touch (fingers and lips)

Modality: stroking, fluttering

191
Q

________ are encapsulated, made of flattened supportive cells arranged in horizontal lamella surrounded by CT. A single ________ branches throughout

A

Meissner’s corpsucles

Nerve ending

192
Q

________ are rapidly adapting so they respond well to movement of objects over the surface and low frequency (10-50Hz)

A

Meissners corpuscle

193
Q

What is the fiber type of Meissner’s corpuscles?

A

Abeta

194
Q

What is the location of Merkel’s discs and their modality?

A

Location- epidermis and hair follicles

Modality- static pressure, texture

195
Q

________ is a tactile receptor that has multiple expanded tip endings each associated with a ______ cell

A

Merkel’s disc

Merkel cell

196
Q

______ are slowly adapting and work with Meissner’s corpsucles

A

Slowly adapting

197
Q

Merkel’s discs together with Meissner’s they are great at _________ sensations and determining ______

A

Great at localizing touch sensations and determining texture

198
Q

What is the fiber type of Merkel’s discs?

A

Fiber type Abeta

199
Q

What is the location of the hair end organ (AKA. Hair follicle receptor or hair plexus) and their modalities?

A

Location: hair follicles
Modality: stroking, fluttering

200
Q

In _______ the nerve ending wraps around the based of the hair follicle

A

Hair end organ (hair follicle receptor, hair plexus)

201
Q

______ are rapidly adapting and mainly detects movement across the body surface

A

Hair end organ

202
Q

What are the fiber types of hair end organ?

A

Type Abeta and Adelta

203
Q

What is the location and modality of ruffini ending (bulbous corpuscle)?

A

Location: deep skin and joint capsules

Modality: skin stretch, degree of joint rotation

204
Q

_______ are enlarged dendritic endings encased in elongated capsules

A

Ruffini ending (bulbous corpuscle)

205
Q

_______ are very slowly adapting. And have fiber type Abeta

A

Ruffini ending (bulbous corpuscle)

206
Q

What is the location And modality of pacinian corpsucles (lamellar corpsucles)?

A

Location- dermis and fascia

Modality - vibration

207
Q

______ are large oval shaped structures with 20-60 concentric epithelial membranes encased in a CT

A

Pacinian corpuscle

208
Q

Most specialized receptors transmit their signals using _____ nerve fibers. Free nerve fiber use slower fibers _____ or ______

A

Abeta

Adelta or C

209
Q

Receptors that detect certain sensations with precision use ______ fibers. (Fast or slow?)

A

Faster

210
Q

Faster fibers are good in detecting what?

A

Precise localization
Minute gradations in intensity
Rapid changes

211
Q

Vibration is best detected by _______ and ________ tactile receptors

A

Pacinian corpuscles and meissner’s corpuscles

212
Q

How can a signal be prolonged? (2 possibilities)

A

Using a reverberating or oscillatory circuit AND

Synaptic After-discharge

213
Q

All sensory information for the somatic segments of the body enters the Spinal cord through the __________

A

Dorsal roots of the spinal nerves

214
Q

Incoming sensory nerves form ______ that ascend the spinal cord

A

Tracts

215
Q

What are the two principle tracts (sensory pathways) in the spinal cord?

A

Dorsal-column- medial lemniscal system (MLS)

Anterolateral (spinothalamic) system

216
Q

Describe the dorsal column MLS tract (fibers and modalities)

A 
Larger myelinated fibers 
High degrees of spatial localization 
Touch sensations with fine gradations of intensity 
Phasic sensations (vibrations)
Movement against skin 
Joint position sense 
Fine gradations of pressure intensity
217
Q

Describe the anterolateral (spinothalamic) system (fibers and modalities)

A 
Smaller myelinated fibers 
Pain sensation 
Thermal sensations 
Crude touch and pressure sensations 
Tickle and itch 
Sexual sensations
218
Q

__________ sensory pathway tract modalities include, touch, vibration, two point discrimination and proprioception

A

Dorsal column medial lemniscal pathway

219
Q

The general layout of most somatic sensory pathways:
First order neuron _______-> ______
Second order neuron _____-> ______
Third order neuron ____ -> _____

A

First order: receptor -> cord/brain stem
Second order: cord/brainstem-> thalamus
Third order: thalamus -> cortex

220
Q

What are the areas/ divisions of the grey matter (5)

A 
Marginal zone
Gelatinous substance 
Nucleus proprius 
Lateral motor neurons 
Medial motor neurons
221
Q

________ are large myelinated fibers form specialized mechanoreceptors enter the SC

A

First order neuron

222
Q

First order neuron in the dorsal column - MLS, divides into ______ and _______

A

Medial and lateral branch

Medial branch ascends the dorsal column
Lateral branch synapses with interneurons

223
Q

The first order neuron continues to ascend the dorsal column the _________ if originating from T6 or up.
OR
________ if originating from source below T6

A

Fasciculus cuneatus

Fasciculus gracilis

224
Q

The fibers from the lowest part of the body project to the most _______ part of the __________
The fibers from the uppermost part of the body project the most _____ part of the ________

A

Medial; fasciculus gracilis

Lateral; fasciculus cuneatus

225
Q

The first order neuron of the dorsal column -MLS terminates/ synapses in the __________ or ________ in the _________

A

Nucleus gracilis or nucleus cuneatus in the medulla oblongata

226
Q

The second order neuron of the anatomy of dorsal column-MLS decussates to ascend in the ___________. Continues up the ___________ of the pons and midbrain and terminates in the ______

A

Medial lemniscus
Medial lemniscus
Thalamus (ventroposterolateral (VPL) nucleus)

227
Q

The third order neuron of the dorsal column -MLS projects from the thalamus to the _________

A

Somatosensory cortex (post-central gyrus)

228
Q

Third order neuron of the dorsal column MLS terminates in the _______ arranged such that the lower body projects to the __________ cortex and the upper body in the ________ cortex

A

Post central gyrus
Lower body-> superior medial cortex
Upper body -> inferior medial cortex

229
Q

Post central gyrus is also known as the __________ cortex and corresponds to brodmanns areas __, ___, ___.

A

Primary somatosensory cortex

3,1,2

230
Q

_________ tract discriminates touch/pressure from the face

A

Trigeminothalamic tract

231
Q

How many layers are there of the somatosensory cortex?

A

Six layers

232
Q

In which of the 6 layers are there incoming 3rd order neurons synapse here first then branch to a more superficial and deep layers

A

Layer four

233
Q

Somatosensory cortex layers ______ , project to neighboring cortical areas

A

I-III

234
Q

layers ____ and _____ of the somatosensory cortex contain outgoing neurons to more distant areas

A

5 and 6

235
Q

Functionally, the neurons of the somatosensory cortex form ________ _______ each serving a sensory modality

A

Vertical columns

236
Q

________ columns respond to proprioception

A

Brodmans 3a columns

237
Q

As you move posterior in the cortical columns from 3a -> 2. What occurs in the neurons?

A

Rapidly adapting -> slowly adapting
Texture and movement -> deep pressure
The farther posterior in the column
3b-> 1 -> 2

238
Q

Based on ________ you would be able to take a corre sample from a part of the post-central gyrus, you would be able to predict the modality, body part, and input/output patterns from that core sample based on location

A

Cortical columns

239
Q

Brodmann’s areas _____ and ____ combine information from multiple sources including the thalamus, visual cortex and auditory cortex

A

Brodmanns areas 5 and 7

240
Q

Brodmanns areas 5 and 7 combine information from multiple sources including ______, ______ and _____

A

Thalamus
Visual cortex
Auditory cortex

241
Q

What brodmanns areas decipher deeper meanings such as is this a ball or a pencil?

A

Areas 5 and 7

242
Q

________ is the ability to determine shape and texture based on feel and not just by sight

A

Stereognosis

243
Q

What is the dorsal column system composed of?

A

Divergent circuits

244
Q

The dorsal column system is composed of divergent circuits which helps with ________

A

Distinguishing weak vs strong stimuli

245
Q

The dorsal columna system is important in _______ and _______

A

Two point discrimination and

Vibration and rapidly changing stimuli sensations

246
Q

________ is used to increase the degree of contrast between two stimuli

A

Lateral inhibition

247
Q

What is an important component in two point discrimination?

A

Lateral inhibition

248
Q

______ and _____ neurons respond to vibrations and rapidly changing stimuli sensations

A

Pacinian and Meissners neurons

249
Q

______ proprioception is the orientation of the different parts of the body with respect to one another

A

Static

250
Q

_______ proprioception is the rate of movement (kinesthesia)

A

Dynamic

251
Q

_______, _____ and _____ are examples of receptors tha relay to the dorsal column and are involved in proprioception

A

Skin tactile receptors, deep joint receptors and muscle spindles

252
Q

The anterolateral pathway modalities are ___? (6)

A 
Pain
Heat
Cold
Crude tactile
Tickle and itch 
Sexual sensations
253
Q

What is the anatomy of the anterolateral pathway in terms of the first order neuron

A

First order neuron enter dorsal horn grey matter and synapse there

254
Q

What is the anatomy of the anterolateral system in terms of the second order neuron?

A

Decussate immediately through the anterior commissure
Enters the anterior or lateral spinothalamic tract and terminat in reticular nuclei of the brain stem or the thalamus VPL and intralaminar nuclei

255
Q

The second order neuron in the anterolateral pathway enters into the anterior or lateral spinothalamic tract and terminates in what locations? (3 possible)

A

Reticular Nuclei of the brain stem

Thalamus VPL and the intralaminar nuclei

256
Q

What is the anatomy of the anterolateral pathway in terms of the third order neuron?

A

It ascends from VPL to the primary somatosensory cortex

257
Q

The _______ spinothalamic tract receives inputs from nociceptors, thermal receptors, visceral afferents, itch receptors

A

Lateral

258
Q

The ______ spinothalamic tract contains A delta and C fibers

A

Lateral

259
Q

_______ spinothalamic tract receives mixed information from visceroreceptors, nociceptors and low threshold Mechanoreceptors (free nerve endings)

A

Anterior

260
Q

The anterolateral pathway velocities of transmission is slower (______ and _____ fibers); spatial localization is ______; gradations of intensities are _____ accurate; rapidly changing signals and vibration sense is ______.

A

A delta and C types
Poorer
Less accurate
Poor

261
Q

In the anterolateral pathway the fibers from the lowest part of the body project to _________ pathway

A

Anterolateral

262
Q

Anterolateral pathway, the fibers from the uppermost part of the body project to the most ___________ part of the pathway

A

Posteromedial

263
Q

Dendrites do transmit electronic current toward the soma, however the more distance that needs to be covered, the weaker the signal gets. This is why it is called __________ conduction

A

Decremental

Neurophysiology (4 decks)

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