ch 17 spinal cord and peripheral nerves

Question 1

spinal cord

Answer 1

• part of the CNS (brain and spinal cord)
• communication highway
• sending info to brain
• brain to respective body area

Question 2

white matter (looks grey)

Answer 2

• white bc myelinated: transmits messages
• tracts: groups of (thousands) axons
• sensory info: to CNS
• motor info: FROM CNS to effector throughout body

Question 3

integration

Answer 3

• integration of incoming and outgoing info: not a ton but some decision-making
• grey matter (H or butterfly dark part) = cluster of cell bodies (little protein)
• spinal reflexes: sensory comes in and automatic responses

Question 4

external anatomy of the spinal cord

Answer 4

• length in adults is 16-18 in in adult humans
• superior end of brain: medulla oblongata (1) foramen magnum beginning of spinal cord
• conus medullaris (2): inferiorly L2
• cauda (tail) equina (horse): extension of pia matter
• divided into vertebral segments: pairs of spinal nerves emerge from each level: cervical (8): each vertebrae (r&l) names based on which vertebrae it exits out. c1-c7 exits above c8 below bc its fake?? ASK, thoracic (12) nerve t1-t12 below, 5 lumbar (2L) r&l, 5 sacral nerves anchors to the coccyx ASK BC NOT WELL EXPLAINED HERE^
• maximum diameter is about 1/2 in: cervical and lumbar enlargement (extra neurons associated with upper limbs

Question 5

protection of the spinal cord

Answer 5

• epidural space: in between mingle layer (hard boney ring and cord), prevents it from crushing it and its bld vessels
• meninges (3): outer later of dura matter and arachnoid, its thick dense connective tissue
• cerebrospinal fluid located in subarachnoid space: buoyant liquid and its shock-absorbing, allows spinal cord to float inside meninges, lots of protection

Question 6

spinal meninges

Answer 6

• dura matter: outer, superficial, subdural space (space between next layer)
• arachnoid mater: spider web, thin, avascular, subarachnoid space (space between layers)
• pia mater: deepest, thin, transparent, highly vascularized, denticulate ligaments (later stability attached to dura), filum terminale (lots of bld vessels), anchors to coccyx

Question 7

internal anatomy

Answer 7

• grey mater: cell bodies, dendrites, unmyelinated axons terminals, neuroglia. receives and integrates incoming and outgoing info
• white mater: fibers that come out of cells bodies (myelinated and unmyelinated, forming tracts), transmits impulses both afferent and efferent

Question 8

ascending tracts

Answer 8

• afferent messages
• sensory pathway contains: first order, second order, third order
  REVIEW

Question 9

descending tracts

Answer 9

• info back to body to iniciate action
• efferent and motor: upper motor and lower motor
  REVIEW SLIDE 7-13

Question 10

spinal nerves

Answer 10

• 31 pairs of mixed: sensory and motor fibers (dorsal root ganglian connects to sensory receptors
• somatic motor: skeletal
• autonomic: smooth organs and glands
• connects to CNS to sensory receptors, muscles, and glands in entire body
  SLIDE 14?????

Question 11

plexi

Answer 11

• network of axons from anterior rami of spinal nerves: cervical C1-C5, brachial C5-T1, lumbar L1-L5, sacral L4-S5
• terminal nerve branches: head away from spinal cord that connects to every single body part
• groups of nerves and branches arise from the plexus
  KNOW WHAT NERVE ROOT/PLEXIS COMES FROM AND WHERE IT CONNECTS

Question 12

cervical plexus

Answer 12

• root C1-C5
• phrenic nerve (end destination: diaphragm) (spinal cord injuries cna be deadly bc it cna harm the phrenic nerve which can harm the diaphragm = no breathing)

Question 13

brachial plexus

Answer 13

• cervical nerve involved: roots C5-T1 innervates upper limbs
  GO BACK:(

Question 14

lumbar plexus

Answer 14

• root L1-L5
• femoral L4-L3-L2 anterior thigh
• obturator: medical thigh (adductor motor)

Question 15

sacral and coccygeal plexi

Answer 15

• root L5-S5
  GO BACK TO SLIDE 23-27 BC I DONT UNDERSTAND:(