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Flashcards in 4. Sensory Receptors and Pathways Deck (27)
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1

What type of neurons are pain receptors?

Simple
Free nerve endings
Unmyelinated

2

What type of neurons are mechanoreceptors?

Complex
Enclosed nerve ending
Myelinated axon

3

What type of neuron is a hair cell?

Specialised receptor cell
Myelinated

4

What receptors are found within the dermis?

Hair receptor
Merkel's disc
Pacinian corpuscle
Ruffini endings
Meissner's Corpuscles

5

What does Merkel's disc react to?

Indentation

6

What do Pacinian corpuscles react to?

Vibration

7

What do Ruffini endings react to?

Stretch

8

What do Meissner's corpuscles react to?

Fine touch

9

What is transduction?

Converting a stimulus to an electrical impulse

10

What is a receptive field?

Area of the body that, when stimulated, results in a change in the firing rate of a sensory neuron

11

How are stimuli coded?

Modality
Location (receptive field)
Threshold
Intensity (no. of receptors, firing rates, type of receptor)

12

What is a tonic receptor?

Fire as long as the stimulus is present at threshold levels
Stops adaptation and desensitisation

13

Name 3 types of tonic receptors

Baroreceptors
Merkel's disc
Nociceptors

14

What is a phasic receptor?

Fire at onset but not continuously
Filters out unnecessary stimuli

15

What 3 types of stimuli are phasic?

Smell
Pressure
Vibration

16

What types of fibre transmit proprioception, vibration and fine touch?

Aa
Ab

17

What types of fibre transmit pain and temperature?

A
C

18

What 2 stimuli don't pass through the thalamus sorting centre?

Smell goes directly to cortex
Balance goes directly to cerebellum with a branch to the thalamus

19

What stimuli travel in the spinothalamic/anterolateral tract?

Pain and temperature

20

Describe the spinothalamic tract?

1. Receptor to spinal cord via dorsal root
Synapse in the dorsal horn
2. Cross spinal cord in anterior commissure
Ascend in contralateral spinothalamic tract
Synapse in the thalamus
3. Thalamus to sensory cortex

21

What stimuli travel in the dorsal column/ medial lemniscal tract?

Proprioception
Vibration
Fine touch

22

Describe the dorsal column medial lemniscal tract?

1. Receptor to spinal cord via dorsal root
Ascend in dorsal column
Synapse in gracile (LL) or cuneate (UL) nucleus of medulla
2. Decussate in lower medulla to enter medial lemniscus
Synapse in thalamus
3. Thalamus to sensory cortex

23

What stimulus travels in the spinocerebellar tract?

Unconscious proprioception

24

Describe the spinocerebellar tract for the upper limb?

1. Receptor to spinal cord via dorsal root
Enters into fasciculus cuneatus
Ascend in cuneocerebellar tract
Synapses in accessory cuneate nucleus in medulla
2. Carries impulse to ipsilateral cerebellum through inferior cerebellar peduncle

25

Describe the spinocerebellar tract for the lower limb?

1. Spinal cord through dorsal root
Ascent in fasciculus gracilis to Clarke's column
Synapses
2. Enter ipsilateral dorsal spinocerebellar tract
Ascends through spinocerebellar tract to medulla
Enters ipsilateral cerebellum via inferior cerebellar peduncle

26

What is convergence?

Neuron can receive input from many neurons

27

What is divergence?

One neuron communicates with many other neurons