LEcture 4 : PNS Flashcards
Sensory receptors
Merchanorecptors thermoreceptors photoreceptors chemoreceptors noriceptors
merchanoreceptors
- physical change to receptor
thermoreceptor
change in temp
photrecpetor
change in light
chemoreceptor
change in chemicals
noriceptors
pain receptor
Proprioceptors
- feed back regarding degree of stretch
- found in skeltal muscles, joints, ligaments and CT coverings of bones and muscles.
- constantly advises the brain of ones movement
Connective Tissue coverings include :
endoneurium
perineurium
epineurim
Endoneurium
CT around a single myleniated axon
perineurium
CT around a group of axons
Epineurium
CT around a nerve proper
Spinal nerves
31 pairs of mixed nerves arise from the spinal cord and supply all parts of the body except the head
8 cervical
C1- C8
12 thoracic
T1-T12
5 Lumbar
L1- L5
3 sacral
S1-S5
1 coccygeal
C0
Nerve plexuses
plexuses are found in the cervical, brachial, lumbar, and sacral regions.
T2-T12 does not have plexues
Cervical plexus
-C1-C5
- cutaneous nerves of the neck, ear back of head and shoulders.
Phrenic nerve (most important) -from C3-C5
extends to the diaphragm.
Brachial Plexus
C5-C8 and T1
- nerves of the upper limb
- major nerves are : musculocutaneous, median, axillary , ulnar and radial.
Lumbar Plexus
L1-L4
- the thigh, abdominal wall and psoas muscle
major nerves are femoral and the obturator nerve.
Sacral plexus
L4-S4
- serves the buttocks, lower limb, pelvic structures and the perineum ( genital organs)
major nerve- sciatic nerve- the longest and thickest nerve of the body.
sciatic nerve has two nerves : tibial nerve and common fibular nerve.
