Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

09. Year 2: Nervous System > Sensory Systems > Flashcards

Sensory Systems Flashcards

1
Q

What are examples of sensory receptors?

A

Mechanoreceptors

Chemoreceptors

Thermoreceptors

Nociceptors

Proprioceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How does the nerve endings of different sensory receptors differ?

A

May have free nerve endings or complex structures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are examples of sensory receptors that have free nerve endings?

A

Nociceptors

Cold receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are examples of complex structures at the end of sensory receptors?

A

Pacininan corpuscle

Meissner’s corpuscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the specific area that sensory receptors respond to stimulus over called?

A

Receptive field

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How do sensory receptors tranduce their adequate stimulus?

A

Into depolarisation, the receptor (generator) potential

This evokes firing of action potentials for long distance transmission

Gives information on modality, intensity and location of the stimulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does the size of receptor potential encode?

A

Intensity of stimulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does the frequency of action potentials encode?

A

Intensity of stimulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does the receptive field encode?

A

Location of stimulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What determines acuity?

A

Density of innervation and size of receptive fields

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are action potentials from sensory receptors transmitted to the CNS by?

A

Axons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the 3 types of primary afferent fibres that mediated cutaneous sensation?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are Aß fibres also known as?

A

Large myelinated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the speed of Aß fibres?

A

30-70m/s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What kinds of sensory information is transmitted by Aß fibres?

A

Touch, pressure, vibration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are Aσ fibres also known as?

A

Small myelinated fibres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the speed of Aσ fibres?

A

5-30m/s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What kind of information is transmitted by Aσ fibres?

A

Cold, “fast” pain, pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are C fibres also known as?

A

Unmyelinated fibres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the speed of C fibres?

A

0.5-2m/s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What kind of information is transmitted by C fibres?

A

Warmth, “slow” pain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the 2 types of primary afferent fibres that mediate proprioception?

A

Aa and Aß (such as muscles spindles, golgi tendon organs etc)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What do proprioceptors give information about?

A

Position and movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What do all primary afferent fibre types enter the spinal cord through?

A

Dorsal root ganglia (or cranial nerve ganglia for the head)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What fibres transmit information from mechanoreceptors?
A*a* and Aß fibres
26
Explain the pathway of mechanoreceptor (Aa and Aß fibres)?
1) Project straight up through ipsilateral dorsal columns 2) Synapse in cuneate and gracile nuclei 3) The 2nd order fibres cross over midline in the brain stem and project to reticular formation, thalamus and cortex
27
Where do mechanoreceptor fibres cross the midline?
Brainstem
28
What do mechanoreceptor fibres project up the spinal cord through?
Ipsilateral dorsal columns
29
What fibres do thermoreceptors use?
Aσ and C fibres
30
What fibres do nociceptive receptors use?
Aσ and C fibres
31
Explain the pathway of thermoreceptive and nociceptive fibres?
1) Synapse in the dorsal horn 2) The 2nd order fibres cross over the midline in the spinal cord 3) Project up through the contralateral spinothalamic (anteriolateral) tract to reticular formation, thalamus and cortex
32
What do mechanoreceptors detect?
Touch, pressure, stretching and motion
33
What do nociceptive receptors detect?
Pain
34
Where do thermoreceptive fibres cross the midline?
Spinal cord
35
Where do nociceptive fibres cross the midline?
Spinal cord
36
How are thermoreceptive fibres transmitted up the spinal cord?
Contralateral spinothalamic (anteriolateral) tract to reticular formation, thalamus, and cortex
37
How are nociceptive fibres transmitted up the spinal cord?
Project up through the contralateral spinothalamic (anteriolateral) tract to reticular formation, thalamus, and cortex
38
Different transmission for sensory information explains consequences of spinal cord injuries, what does damage to dorsal columns cause?
Loss of touch, vibration, proprioception below lesion on ipsilateral side
39
Different transmission for sensory information explains consequences of spinal cord injuries, what does damage to anteriolateral quadrant cause?
Loss of nociceptive and temperature sensation below lesion on contralateral side
40
Where is the ultimate terminate of all sensory receptor fibres?
Somatosensory cortex (S1) of the postcentral gyrus
41
What is S1?
Somatosenosry cortex
42
What are the endings of sensory fibres grouped according to?
Location of the receptors, forming sensory homunculus
43
What are the steps of processing in sensory pathways?
Adaptation Convergence Lateral inhibition
44
What is the adaptation step of processing in sensory pathways?
Decline in the electrical response of a receptor neuron over time in spite of the continued presence of an appropriated stimulus of constant strength Is apparent as a gradual decrease in frequency of spikes generated within the receptor neuron
45
What are the 2 kinds of adapting that sensory receptors can display?
Rapidly adapting Slowly adapting
46
What are consequences of convergence occuring when processing sensory information?
Saves on neurons But reduced acuity May underlie referred pain
47
What is the lateral inhibition step of processing in sensory pathways?
Activation of one sensory input causes synaptic inhibition of its neighbours
48
What are consequences of lateral inhibition in sensory receptors?
Gives better definition of boundaries Cleans up sensory information
49
What is perception?
The ability to see, hear or become aware of something through the sense, or the way something is interpreted
50
What are examples of the different kinds of pain?
Sharp, stabbing vs diffuse, throbbing Fast (initial pain) vs slow (delayed) pain Acute vs chronic pain Visceral pain Referred pain Phantom limb pain
51
What is signal transduction?
Transmission of molecular signals from a cell's exterior to its interior
52
What is signal transduction in nociceptors activated by?
Low pH, heat (via ASIC, TRPV1 etc) Local chemical mediators (such as bradykinin, histamine, prostaglandins)
53
What are examples of local chemical mediators that activates signal transduction in nociceptors?
Bradykinin, histamine, prostaglandins
54
Explain the processing of nociceptive pathways?
1) Segmental controls (such as gate theory control of pain where activity in A*a*/ß fibres activates inhibitory interneurons) 2) Inhibitory interneurons release opiod peptides (endorphins) that inhibit transmitter release from Aσ/C fibres, "closing the gate" 3) Descending controls, the same inhibitory interneurons are also activated by descending pathways from PAG and NRM, hence also "closing the gate" 4) Transmitted to thalamus
55
What does PAG stand for?
Peri-aqueductal grey matter
56
What does NRM stand for?
Nucleus raphe magnus
57
What is the medical term for the inability to feel pain?
Analgesia
58
What is the "gate control theory of pain"?
Non-painful stimulus input closes the nerve "gates" to painful input, which prevents pain sensation form travelling to the central nervous system
59
What can analgesia be achieved with?
Non-steroidal anti-inflammatory drugs (NSAIDs) Local anaesthetics Transcutaneous electrical nerve stimulation (TENS) Opiates
60
What does NSAIDs stand for?
Non-steroidal anti-inflammatory drugs
61
How do NSAIDs achieve analgesia?
1) Prostaglandins sensitive nociceptors to bradykinin 2) NSAIDs inhibit cyclo-oxygenase which converts arachidonic acid to prostaglandins 3) So NSAIDs work well against pain associated with inflammation
62
How do local anaesthetics achieve analgesia?
Block Na+ action potential and therefore all axonal transmission
63
What does TENS stand for?
Transcutaneous electrical nerve stimulation
64
What is an example of an opiate?
Morphine
65
How do opiates achieve analgesia?
Reduce sensitivty of nociceptors Block transmitter release in dorsal horn (hence epidural administration) Activate descending inhibitory pathways

09. Year 2: Nervous System (48 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions