Module D-02 Flashcards Preview

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Flashcards in Module D-02 Deck (63)
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1

What are the 5 somatosensory modalities?

Touch, vibration,proprioception(muscular),pain and temperature

2

What type of neurons are the somatosensory receptor neurons?

Pseudounipolar

3

Where are sensory endings of the somatosensory receptor neurons found?

In skin or in (close to) muscle

4

Where are cell bodies of the somatosensory receptor neurons found?

Dorsal root and Cranial nerve Ganglia

5

What are the 2 Cutaneous touch receptors?

1)Merkel’s disks
2)Ruffini’s endings

6

What type of specific touch is transduced by Merkel's disks?

discriminative touch

7

What type of specific touch is transduced by Ruffini’s endings?

skin stretch

8

What are the 2 Cutaneous receptor specific for Vibration?

1) Meissner's corpuscles
2) Pacinian corpuscles

9

What type of vibration do Meissner's corpuscles have highest sensitivity?

highest sensitivity / lowest threshold for lower frequencies of about 50 Hz

10

What type of vibration do Pacinian corpuscles have highest sensitivity?

highest sensitivity / lowest threshold for higher frequencies of about 300 Hz

11

What type of receptors transduce the signal for pain and temperature?

Free nerve endings

12

What type of free nerve endings for prickling pain and burning pain?

- pricking pain by rapidly adapting mechano-sensitive or thermo-sensitive receptors,
- burning pain by slowly adapting polymodal receptors

13

What type of free nerve endings for Temperature?

Cold and warm receptors

14

What type of receptors transduce proprioception (position sense)?

Proprioceptors:
Muscle spindles and Golgi tendon organs

15

Where are muscle spindles found?

Embedded in extrafusal fibers of working musculature

16

What type of receptor are the primary receptor of muscle spindle ?

Rapidly adapting receptor with a 1a afferent fiber

17

Which receptor for deep tendon reflex(myotatic reflex)?

Ia afferent fiber

18

What type of receptor is the secondary receptor of a muscle spindle?

slowly adapting receptor class II afferent fiber

19

What type of info does the primary muscle spindle fiber (1a)transduce?

Stretch

20

What type of info does the secondary muscle spindle fiber (class II) transduce?

Muscle length

21

Where are golgi tendon organs located?

border between muscle and tendon

22

What type of receptor is the golgi afferent fiber?

1b

23

What do the 1b fiber form?

afferent limb of inverse myotatic reflex

24

Afferent fibers from proprioceptors form which important pathways to the cerebellum ?

dorsal and ventral spinocerebellar tracts (don't reach consciousness)

25

Somatosensory receptors use four different fiber types:

1)Large myelinated fibers (muscle 1 and cutaneous A alpha)
2)medium myelinated fibers (muscle II and cutaneous A beta)
3) small myelinated fibers (muscle III and cutaneous A delta)
4) unmyelinated fibers (muscle IV and cutaneous C)

26

Size and conduction velocity of Large and medium myelinated fibers

diameters : up to 20 μm
conduction velocities : up to 120 m/sec

27

What type of receptors use Large and medium myelinated fibers?

cutaneous mechanoreceptors and proprioceptors

28

What type of sensory info do Large and medium myelinated fibers carry?

touch, vibration and proprioception

29

Size and conduction velocity of small myelinated fibers

diameters: about 1 μm
conduction velocities : 5 m/sec

30

Size and conduction velocity of unmyelinated fibers

diameter: 0.2 and 1.5 μm
conduction velocities: from about 0.5 to about 2 m/sec.