Somato & Neuro 1 Flashcards

1
Q

Sensory systems

A

Somatosensory
Olfactory
Gustatory
Visual
Auditory
Vestibular

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2
Q

Function of sensory system

A

Detect changes in the external and internal environment. Focus on afferent signals

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3
Q

Specific branches of sensory systems

A

Somatosensory - touch, temp, pain, pressure, limb position
Olfactory - volatile chemicals
Gustatory - taste
Visual - light
Auditory - sound
Vestibular - movement and head position

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4
Q

Steps in sensory perception

A

Detection & transduction
Transmission
Modulation
Perception

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5
Q

Break down of sensory perception

A

Detection & transduction - receptor translates stimulus from chemical to electrical signal
Transmission - action potential propagated
Modulation - synapses on neurons with input form other sources
Perception - sensory cortex, not all sensory info goes to cortex (subconscious)

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6
Q

Sensory receptor types

A

Mechanoreceptors
Photoreceptors
Nociceptors
Chemoreceptors
Thermoreceptors

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7
Q

Mechanoreceptors

A

Activated by mechanical forces (touch, stretch, pressure, vibration, sound waves)

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8
Q

Photoreceptors

A

Activated by light

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9
Q

Nociceptors

A

Activated by potential / actual potential tissue damage

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10
Q

Chemoreceptors

A

Activated by binding of chemicals

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11
Q

Thermoreceptors

A

Activated by heat or cold

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12
Q

Primary receptor

A

Specialized terminals of the sensory neuron
Receptors for touch, pain, temperature

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13
Q

Secondary receptor

A

Specialized non-neural cells that send a chemical signal to the sensory neuron
Rods and cones in retina
Hair cells in ear

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14
Q

Adaptation

A

Decreased sensitivity to stimulus over time

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15
Q

Slow adapting receptors

A

Tonic
Action potentials continue to be generated, but slower rate = continuous input to NS with duration of stimulus

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16
Q

Rapid adapting receptors

A

Phasic
After initial firing, action potentials stop

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17
Q

TRP channels

A

Ion channels that convert sensory stimulus into electrical potential
28 different channels
Sensitive to pain, temp, taste, pressure, light
Permeable to cations (Na, Ca)

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18
Q

Origin of TRP channels

A

Blind fruit flies

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19
Q

Clinical significance of TRP channels

A

Mutation can cause polycystic kidney disease
Possible target for pain medication

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20
Q

Modulations

A

Tactile: pressure, vibration, light touch
Proprioceptive: limb position & movement
Thermal: heat, cold, changes in temp
Pain: extreme pressure or temp, tissue damage, chemicals

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21
Q

Location for modality receptors

A

Skin, muscle, tendons, joints, teeth, mucus membranes, cornea

22
Q

Somatosensory pathways in body

A

Sensory receptor
Sensory neuron - spinal nerve
2 Interneurons
Synapses in
- spinal cord, brainstem
- thalamus
- sensory cortex

23
Q

somatosensory pathways in head

A

Sensory receptor
Sensory neuron - cranial nerve
Interneurons
Synapses in
- brain
- thalamus
- sensory cortex

24
Q

Skin histology

A

Epidermis - stratified squamous epi, some sensory nerve ending
Dermis - collagen, glands, hair follicles, vessels& nerves
Subcutis - adipose tissue, blood vessels

25
Q

Free nerve endings

A

Simplest nerve receptors
Thermoreceptors
Nociceptors

26
Q

Encapsulated/specialized nerve endings

A

Low threshold mechanoreceptors
Proprioceptive

27
Q

Low threshold mechanoreceptors

A

Different size receptor fields
Pacinian corpuscle
Meissner corpuscle
Ruffian corpuscle
Merkle’s disk

28
Q

Proprioceptors

A

Golgi tendon organ
Muscle spindle
Joint kinesthetic receptor

29
Q

Something strange abt pacinian corpuscles

A

Cats have pacinian corpuscles in the pancreas
Coincidence with Hz and purring …?

30
Q

Merkle cell carcinoma

A

Dogs - usually benign
Cats - often malignant

31
Q

Nociceptors

A

Respond to actual or potential tissue damage
Multiple types - inflammation, mechanical, thermal, pinprick
Many involve TRP channels

32
Q

Thermoreceptors

A

Low threshold receptors (cold)
- myelinated fibers (fast)
- TRPM ion channels (activated also by menthol)
High threshold receptor (warm)
- unmyelinated fibers (slow)
- TRPV ion channels (activated by capsaicin)

33
Q

Muscle spindle

A

Sensory organ
Short intrafusal muscle fibers
Surrounded by fibrous capsule
Arranged in parallel to extrafusal fibers
Helps maintain posture

34
Q

Innervation of muscle spindle

A

Sensory
- type 1a: info abt muscle length & velocity of contraction
- type 2: info abt muscle length
Motor
- gamma motor neurons

35
Q

Golgi tendon organs

A

Located in tendons
Innervated by type 1b sensory fibers
Arranged in series w extrafusal muscle fibers
Prevents excessive muscle contraction/damage

36
Q

Golgi tendon organ Interneurons

A

Inhibit agonist alpha motor neuron (relaxation)
Excite antagonist alpha motor neuron (contraction)
Inverse myotatic reflex

37
Q

Joint kinesthetic receptors

A

Most active at extremes of flexion & extension
Limit detectors

38
Q

First order somatosensory neurons

A

Pseudounipolar neurons
Peripheral process
Cell body
Central process

39
Q

Pseudounipolar neurons

A

Cell body has one process, splits into peripheral & central branches

40
Q

Peripheral process

A

Modified or bare nerve endings in the skin, muscle, joint. Part of axon in spinal or cranial nerves

41
Q

Cell body of first order SSN

A

Located in DORSAL root ganglia (body) or cranial nerve ganglia (head)

42
Q

Central process for first order SSN

A

Synapses w second order neuron in spinal cord or brainstem

43
Q

Types of sensory axons

A

A alpha
A beta
A gamma
B
C

44
Q

A alpha axon

A

Muscle spindles, golgi tendon organs

45
Q

A beta axons

A

Muscle spindles, mechanoreceptors

46
Q

A gamma axon

A

Pain (stabbing) & temperature

47
Q

B axon

A

Autonomic

48
Q

C axon

A

Pain (burning), temperature

49
Q

sensory spinal nerves

A

One spinal nerve for every division
Contain sensory and motor axons
Each nerve innervates a strip of skin called the Dermatome - organized sensory input
Detects sensations in muscle, organ, connective tissue

50
Q

Location for sensory spinal nerves

A

cell bodies for sensory neurons are in the DORSAL root ganglia

51
Q

Dorsal root ganglia

A

Located in the cell bodies (ncb) of the first order sensory neurons