(3) Spinocerebellar pathways Flashcards Preview

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Flashcards in (3) Spinocerebellar pathways Deck (47)
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1

summary: posterior/dorsal column medial lemniscus pathway carries what type of sensory information (4)

proprioception
fine touch
pressure
vibration

2

summary: anterolateral/spinothalamic pathway carries what type of sensory information (5)

crude touch
pressure
pain
temperature
itch

3

what are the basis of these different sensory pathways?
(dorsal column and spinothalamic)

different types of sensory receptors in skin, joints and muscle

4

cutaneous receptors do what

mediate sensory information in (sensory) spinal cord pathways

5

types of cutaneous receptors (4 sensations)

vibration= Pacinian corpuscle

touch= Meissner corpuscle (fine touch), Merkel endings (fine touch), endings around hairs, free nerve endings

pressure= ruffini endings

pain/temp/itch= free nerve endings

6

2 touch receptors from hairy skin

1) receptors endings wrap around hairs

2) Merkel cell (in basal layer of epidermis)

7

when skin is deformed there is a change in which receptor

change in merkel cell receptor onto nerve cells, and transmit to spinal cord

8

where is merkel cell found, responsible for?

- hair and glabrous skin

- responsible for ability to perform fine tactile discriminations with fingertips (2 pt discrimination)

9

where are meissner corpuscle found

they are encapsulated endings in dermal papillae of hairless skin

- layer of Schwann cells within the capsule

10

where are Pacinian corpuscles found

subcutaneously over entire body and connective tissue sites

- rapidly adapting

11

where are ruffini endings found

in dermis and subcutaneously, and other connective tissue sites

- slow adapting

12

what sensory endings are found in glabrous skin?

fine touch: (M) meissner corpuscle, (Me) Merkel cell

vibration: (PC) Pacinian corpuscle

pressure: (R) ruffini ending

13

what is 2 point discrimination

minimum distance by which 2 stimuli can be separated and perceived as 2 stimuli

14

proprioceptors

another way sensory information is mediated in spinal cord pathways

15

proprioception

perception of the position of parts of the body

16

proprioceptors are derived from

vibration, touch and pressure receptors in skin and joints, and muscle spindles and Golgi Tendon organs at myotendinous junctions and joints

17

muscles are supplied with 2 important types of encapsulated receptors

- muscle spindle (unique to muscle)

- Golgi tendon organ (similar to ruffini ending- pressure)

18

what is the function of muscle spindles in skeletal muscle

relay sensory information of proprioceptors and DETECT MUSCLE LENGTH

- provide info about position of body in space

19

muscle spindles are...

long, thin, stretch receptors scattered throughout striated muscle in body

20

muscle spindles consist of...

intrafusal muscle fibers (inside the spindle)
- small muscle fiber with capsule surrounding middle 1/3 of fibers

- ends of intrafusal muscle fibers are attached to extrafusal fibers
(when muscle is stretched, intrafusal fibers also stretched)

21

golgi tendon organ tracks...

TENSION developed by tendon

22

how does a golgi tendon organ function

- large diameter sensory fibers enter capsule and branch into fine processes that are inserted among collagent bundles
- tension on capsule squeezes fine processes
- resulting distortion stimulates them

23

3 unconscious proprioception/sensory pathways carried by spinal cord to cerebellum via ....

posterior/dorsal spinocerebellar tract

anterior/ventral spinocerebllar tract

cuneocerebellar tract

24

what is the function of the cerebellum

integration center for motor control

25

9 parts to posterior/dorsal spinocerebellar tract

(ascending, sensory, unconscious)

1) proprioceptors (muscle spindles, Golgi tendon) in lower leg
2) primary sensory neuron in DRG
3) white matter of spinal cord
4) ascend in fasciculus gracilis (spinal cord)
5) synapse with dendrites of Clarke's nucleus/nucleus dorsalis (T1-L2/L3)
6) ascend ipsilaterally in posterior spinocerebellar tract (PSCT)
7) caudal pons (lower)
8) inferior cerebellar peduncle
9) cerebellum

26

origin of posterior/dorsal spinocerebellar tract

clarke's nucleus

aka nucleus dorsalis

27

body part --> posterior/dorsal spinocerebellar tract

trunk, lower extremity

(remember fasciculus/nucleus gracilis)

28

major inputs posterior/dorsal spinocerebellar tract

mechanoreceptors in muscles, joints and skin

29

midline crossing posterior/dorsal spinocerebellar tract

NONE

30

peduncle used to enter cerebellum posterior/dorsal spinocerebellar tract

inferior cerebellar peduncle