Sensory Receptors and Exteroception Flashcards

1
Q

Weak left hand, clumsy left leg. Abnormal temperature and pinprick sensation in right leg. Loss of vibration sense in left hand. Left plantar response extensor (Babinski)

A

Hemisection of the left spinal cord (Brown-Séquard)

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2
Q

Hand grips weak bilaterally. Bilateral decreased touch and vibration below his knees. Normal pinprick, except in the palm of his hands. No truncal sensory level.

A

Acute inflammatory demyelinating polyneuropathy (Guillain-Barré)

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3
Q

Special Sensory Systems

A

Light- seeing
Air Pressure- hearing
Chemical- olfaction; taste

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4
Q

sensory receptor cells depolarization of the membrane in the synaptic region causes opening of ______________ eliciting an increase in intracellular calcium, which triggers synaptic vesicle fusion and release of chemical transmitter(s) to which the second order cell is sensitive.

A

voltage-dependent calcium channels

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5
Q

Exteroception Somatosensory system

A

vibration- touch

Pain/Temp-

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6
Q

Depolarizing receptor potentials. Receptors that depolarize to their adequate stimulus
generally do so as a result of an increase in:

A

nonspecific cation conductance in the receptive area membrane.

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7
Q

Sensory receptor cell characteristics

A

have somas/ nucleus, synapse, second order neuron, sensory ending

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8
Q

The process of detection of a sensory input and transformation of information into a change in neuronal action potential – a neural signal - is called :

A

transduction.

Stimulus–> voltage change

transduction channels are not voltage-dependent

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9
Q

Sensory endings are _____ dependant

A

Stimulant

Not voltage

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10
Q

An example of a receptor that hyperpolarizes upon stimulation is the

A

rod photoreceptor

resting membrane potential of
approximately –40 mV due to a substantial resting cation conductance

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11
Q

Voltage dependant channels with 2 gates:

A

Na channel

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12
Q

Some receptors, such as hair cells of the auditory system, respond to stimulation with an oscillatory change in generator potential alternating between:

A

depolarization and

hyperpolarization

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13
Q

Retina has 2 cell types

A

Cone cells, color

rod cells, light

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14
Q

Receptors that hyperpolarize in response to stimulation have resting potentials that lie between 0 mV and Ek (-70 mV), generally:_____

A

-30 to -40 mV

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15
Q

Proprioception

A

you do not need to think a lot to move. Brain knows where hand is by: Detecting stretch of muscles (muscle spindles)

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16
Q

Muscle Spindle

A

Direct channel that opens when stretched

Allows proprioception

17
Q

Photoreceptors (rods) are NOT _____ and they DO NOT have:

A

NOT channels

NO action Potentials

18
Q

Photoreceptors (rods) ARE _____

A

second messenger systems

19
Q

Second Messenger system of Rods

A

Light–> rhodopsin (trans)–> activate G Protein–> activate cGMP phosphodiesterase (PDE)–> PDE hydrolyzes cGMP (↓ cGMP)–> Closes Na Channel

20
Q

_______ opens the Na/ K channel of rods

A

cGMP

cGMP gated

21
Q

Light ________ the cell, the more light, the greater the intensity

A

HYPERPOLARIZES

22
Q

Retina is in ___ conformation in the dark

A

cis- (kinked/angles)

23
Q

Retina is in ___ conformation in the presence of light

A

Trans- able to detect g protein

24
Q

_______ or perceived amount of a sensation depends on the stimulus strength.

A

Intensity

Long sensory receptor cells code stimulus intensity as an increase in action potential firing frequency.

25
Q

transduction channels are not:

A

voltage-dependent
Key: Second messenger system that opens or closes channel
*Can amplify

26
Q

Second messenger system types and key point

A
  • Vision
  • capsaicin

MASSIVE amplification

27
Q

_____ sense has no second messenger

A

Touch (somatosensory)
Proprioception
*Directly gated channel

28
Q

A-Beta

A

Mechanoreceptors of skin, secondary muscle spindle afferents

29
Q

_______ has direct channel but no action potential

A

Auditory

30
Q

The concept of labeled lines:

A

Conscious appreciation of sensory modality is determined by specific neuronal connections from sensory organs through thalamus to cerebral cortex.

31
Q

There is a separate chain of neurons ________ for each sensory system

A

(a separate labeled line)

32
Q

Anatomically, there are separate pathways for the different sensory systems, illustrating the fact that the central nervous system preserves the distinctions inherent in its ___________

A

receptor inputs

33
Q

The question of how the brain knows when light is hitting retina VS air vibrations at eardrum is answered by stating that different nerve cells are active for the two kinds of stimulation. Thus, ________ (e.g., hearing, vision, taste, touch, pain, pressure on skin, heat, cold, smell, etc.) is coded by which nerve cells are active.

A

stimulus modality