COM1 Physiology C48 week 3 Flashcards
(99 cards)
1
Q
What are somatic senses
A
Nervous mechanisms that collect sensory informtion from throughout the body
2
Q
Name the 3 types of Somatic sense
A
- Mechanoreceptive sense
-Thermoreceptive sense
-Pain sense
3
Q
What do mechanoreceptive senses detect
A
-They detect mechanical displacement - pressure , vibration
4
Q
What do thermoreceptive sense detect
A
- They detect heat and cold
5
Q
What is pain sense activated by
A
- Activated by tissue damage
6
Q
What do tactile sense include
A
- Touch
-Pressure
-Vibration
-tickle
7
Q
Name the 4 alternatice classifications of somatic sensations
A
- Exteroceptive
-Proprioceptive
-Visceral sensations
-Deep sensations
8
Q
What do position senses include
A
-Static position sense
-Rate of movement sense
9
Q
What is static position sense the awareness of
A
Awareness of body position at rest
10
Q
What is the rate of movement sense awarness of
A
- Awareness of motion
11
Q
What is Exteroceptive sensations
A
Sensations from the surface of the body
12
Q
What is Proprioceptive sensations
A
Sensations related to body postions and movements
13
Q
What is visceral sensations
A
Sensations from internal organs
14
Q
What is deep sensations
A
- Sensations from deep tissues
15
Q
What does touch sensation result from
A
- The Stimulation of skin or tissues
16
Q
What does pressure sensation result from
A
- Results from deformation of deeper tissues
17
Q
What does vibrations result form
A
- Rapidly repetitive sensory signals
18
Q
Name the 6 types of Tactile receptors
A
- Free nerve endings
-Meissners corpuscles
-Merkels Discs
-Hair end organs
-Ruffinis Ending
-Pacinian corpuscles
19
Q
Name the only tactile receptor type found in the cornea
A
Free nerve endings
20
Q
What is the function of free nerve endings (detection)
A
They detect general touch and pressure
21
Q
Where are Meisnners corpuscles found
A
-Non hairy skin
22
Q
What is the function of Meisnners corpuscles + characteristics
A
- Detect movement over skin and low frequency vibration
Characteristics:
-Highly sensitive
-Adapt rapidly
23
Q
What is the function of Merkels Discs
A
- Continuous touch detection and texture identification
24
Q
Where is merkels disc found
A
- In both hairy or non hairy skin
25
Where are hair end organs found
Around hair roots
26
What is the function of hair end organs
- Detect movement of hairs
27
Where is Ruffinis Ending found
- Deep in skin and joints
28
What is the function of ruffinis ending
- They detect sustained pressure + tissue deformation
29
Where is Pacinian corpuscles found
- Deep in skin and fascia
30
What is the function of pacinian corpsucles
- They detect rapid vibrations
31
Name the 2 ways tactile signals can be transmitted
- Type Aβ fibers
- Type Aδ & Type C fibers
32
Name the tactile receptors that use Type Aβ fibers( Fast conducting)
- Meissners corpuscles
-Pacinian corpuscles
- Merkels disc
33
Name the tactile fibers that use Type Aδ
- Free nerve endings
34
What is Type Aβ fibers used for
-Precise, localised and rapid touch info
35
What is Type Aδ & Type C fibers used for
- Carrying crude sensations like tickle and itch
36
What type of vibrations does pacinian corpuscles detect
- Detect high frequency vibrations
37
What type of vibratiosn does Meissners corpuscles detect
- Low frequency vibrations
38
What is tickle and itch detected by
- Rapidly adapting free nerve endings in superficial skin
39
How do signals travel when someone gets a tickle and itch
- Via Type C unmyelinated fibers
39
How does scratching revlieve itches
- By removing irritants
- Triggering pain which inhibits itches via lateral inhibition in the spinal cord
40
Name the 2 main sensory pathways
- Dorsal column
-Anterolateral system
41
Explain the difference in fiber size, corssing point between dorsal column and anterolateral pathway
Dorsal column:
-Large myelinated
-Crosses in medulla
Anterolateral:
-Small myelinated
-Crosses in spinal cord
43
How does the dorsal column transmit info
- carries signals upwards through the dorsal column to the medulla
- crosses in the medulla
- Then continues to the thalamus via the medial lemniscus
44
How does the anterolateral systems transmit info
- Signaos Synapse in the dorsal
Horns and cross in the spinal cord
- ascended throught the anterior and lateral white columns
-Terminate in the lower brain
45
Explain how and what happens in entering the spinal cord in the DorsaL Column
- Large myelinated fibers from mechanorecpetors enter via the dorsal roots
- Then each fiber divides into 2 branches
- Medial branch
-Lateral branch
46
Explain what happens in the medial branch in the Dorsal Column-Medial leminsical system
- Turns medially, then ascends directly in the dorsal column toward the brain
47
What is the medial branch responsible for
- Carrying sensory signals upwards to higher centers
48
What happens in the lateral branch of the Dorsal column Medical leminiscal system
-Enters the dorsal horn of the spinal grey matter and branches multiple times
- The ranches synapse with local neurons
49
What are the 3 key functiosn of the local nerons in the lateral branch
- Send fibers back to the dorsal column
- Terminate locally in the spinal cord
-Give rise to the spinocerebellar tracts
50
In the Dorsal Column where do the fibers from lower body lie
- Centrally in the dorsal columns
51
In the dorsal column how are the fibers from higher body parts added
- Added in layers laterally
52
In the thalamus how is spatial orientation maintained
- The tail ends of the body is reperesnted by the lateral portions of the ventrobasal complex and
-The head and face is represented by the medial areas of the complex
53
In the Dorsal column How is the left side of the body represented
- It is represneted in the right side of the thalamus
54
In the dorsal column where is the right side of the body represneted
In the left side of the thalamus
55
What is the cerebral cortex divided into
- 50 distinct brodmann areas
56
Posterior to the central sulcus is also known as what lobe + function
- Parietal lobe
- Processes snsory signals
57
Anterior to central sulcus is also known as what lobe + what it contains +function
- Frontal lobe
-Contains motor cortex
- Controls muscle
movement based on sensory inpit
58
Where are Somatosensory signals processed
- Anterior parietal lobe
59
Which lobe is visuals signals processed in
- Occipital lobe
60
What lobe is auditory signals processed in
- Temporal lobe
61
Where is somatosensory Area 1 located
Loacted in the postcentral gyrus
62
What does the somatosensory Area 1 recieve signals from
Opposite side of the body
63
Explain the difference between Somatosensory Area 1 and Somatosensory Aea 2 in terms of localisation
S1 is more localised than S2
64
Where does the somatosensory Area 2 recieve input from
Both sides of the body, S1 ( somatosnsory cortex 1) , other snesory areas
65
Does damage to the Somatosensory area 2 significantly affect S1
NO
66
Is there a lot of info regarding Somatosensory area 2
No
67
Where is the nose, lip mouth and face represented
- Lateral part of Somatosensory area 1
68
Where is the head neck , shoulders , trunk and legs reoresented
- Medial part of the Somatosensory area 1
69
What is the cerebral cortex composed of
- Six layers of neurons , numbered 1 to 5`
70
Which of the layers in the cerebral cortex the first to recieve incoming sensory signals
- Layer 4
71
What does the 1 and 3 layers of the cerebral cortex recieve
They recieve diffuse, nonspecific input from the lower braiN centers
-
72
What does the 1 and 3 layers of the cerebral cortex regulate
- Regulate overall excitability of the cortical region
73
# SEND axons
What is the function of the 2 and 3 rd layers of the cerebral cortex
- Send axons across the corups callosum to corresponding areas in the oppsoite hemisphere
74
What is the 2 and 3rd layer of the cerebral cortex involved in
- Interhemispheric communication
75
What is the function of the output layers of layers 5 and 6
- Sends signals to deeper CNS structures
76
What does the 5th layer of the cerebral cortex contain + where they project
-Contains large neurons projecting to basal ganglia, brainstem, spinal cord
77
What is the function of the 6 layer of cerebral cortex(2)
- It sends many axons to the thalamus ,
- Influencing incoming snesory input regulation
78
How is the sensory cortex organized
- Into vertical columns of neurons
79
What does each column in the sensory cortex process
- Processes input from a specific body area and sensory modality
80
How do the column s of the sensory cortex work in the 4 layer of the cerebral cortex
- Work independently
81
What is the function of the most Anterior postcentral gyrus( Brodmanns area 3A)
- Resonds mainly to muscle, tendon and joint stretch receptors
82
Moving posteriorly in S1 explain how the vertical columns respons
- The columns respond more to slowly to adapting skin receptors
83
What can widespread bilateral excision of the S1 cause+ examples
Loss of fine sensory judgments such as:
-Poor localization of sensations
-The perosn Cannot judge pressue
-The person cannot judge weight
-They cannot detect texture
84
Where is Brodma s area 5 + 7 located
- In the parietal cortex behind Somatosensory area 1
85
What do Brodmaans area 5 + 7 play important roles in
- Deciphering deeper meanings of the sensory information
86
What is Brodmaans area 5 + 7 called and why
- Somatosensory association areas
- Becuase they play important roles in deciphering deeper meanins of the sensory infirmation
87
Where do Brodmanns area 5 + 7 ( somatosensory )association areas integrate information from
- S1
-Thalamus
-Visual and auditory cortices
88
What happens when the somatosensory Association area is removed from one side of the brain
- The person cannot recognice complex objects
-Loose sense of body form on the opposite side
89
What does the Dorsal Column Medial lemniscal Pathway involve
- Divergence at each spinal level, where central neurons fire more intensly with stronger stimuli
90
What is 2 point discrimination used for
- To test tactile discrimination, which is sued to deterimes a persons 2 point discrimination ability
91
What does the 2 point discrimination test depend on
- Density of tactile receptors
92
What is 2 point discrimantion enhanced by
- Lateral inhibition
93
What is the function of lateral inhibition
- Enhances contrast by inhibiting surrounding neurons
94
Where does lateral inhibition occur ate
- Dorsal column nuclei
-Ventrobasal thalamic nuclei
-Somatosensory cortex
95
What is the dorsal column pathway specialised for
Rapidly changing stimuli
96
Name the 2 types of postion sense ( proprioception)
- Static
-Dynamic
97
Explain static as a type of position sense( proprioception)
- Awareness of body part orientation
98
Explain Dynamic as a type of position sense ( proprioception)
- Awareness of movement speed
99
Name the receptors involved in position sense
- Skin tactile recepots
-Deep joint receptors
-Muscles spindles
-Ligaments
-Pacinian corpuscles
