Chapter 13 Flashcards
4 subdivisions of the spinal cord
- cervical
- thoracic
- lumbar
- sacral
cervical
- spinal nerves
- where does the 1st cervical nerve arise
- where does C2-C7 arise
- where is C8 located
- C1-C8
- between the skull and C1
- arise superior to vertebrae
- between C7 and T1
Thoracic
- spinal nerves
- nerves are
- T1-T12
- nerves are inferior to vertebrae
how many lumbar spinal nerves
L1-L5
How many sacral spinal nerves
S1-S5
2 enlargements
- purpose
- what are they
- contains extensive grey matter dedicated to sensory and motor control of limbs
- 1.the cervical (C4-T1) supplies nerves to upper shoulder and limbs
2. the lumbosacral (T9-T12) supplies nerves to lower limb and pelvis
conus medullaris
tapering end of cord at level L1
-in between thoracic and lumbar
Filum terminale
fibrous extension of pia mater that extends and attaches to coccyx
Cauda Equina
collection of nerve fibers that extends into lower vertebral column
spinal meninges
- definition
- continuous with
specialized membranes surrounding the spinal cord
-continuous with cranial meninges at foramen magnum
what is the epidural space used for
epidural block
Posterior gray horn
contains sensory neurons
gray matter
cell bodies, unmyelinated axons, dendrites, neuroglia
white matter
myelinated axons
anterior gray horn
contains somatic motor neurons
2 functions of the spinal cord
- conducts sensory and motor info
2. serves as a reflex center
Tracts of the spinal cord
- definition
- function
- 2
- groups of axons inside the CNS
- Relays same type of info in same direction
- Ascending tract
- descending tract
- Ascending tract
Ascending tracts
- definition
- what does each tract carry
sensory axons that conduct impulses from periphery to brain
-different types of sensory info
Descending tracts
- definition
- what does each tract carry
- motor axons that conduct impulses from brain to muscle and glands
- different types of motor info
relflex
- definition
- function
- 2 types
- a quick, involuntary response to a stimulus that passes along a reflex arc
- act to preserves homeostasis by making rapid adjustments
- somatic reflex and autonomic reflex
5 components of a reflex
- receptor
- sensory neuron
- CNS for info processing
- motor neuron
- Effector
receptor
detects a signal and initiates a response
sensory neuron
conducts impulses to spinal cord
motor neuron
conducts impulses away from CNS
effector
what responds: muscle or gland?
what is a mixed spinal nerve
contains sensory and motor info
2 points of attachment for spinal nerves (PNS)
- posterior root
2. anterior root
posterior root
dorsal root
-sensory info
anterior root
ventral root
-motor info
2 branched of peripheral spinal nerves
- posterior branch
2. Anterior branch
Posterior branch (PNS)
- known as
- function
- dorsal ramus
- supplies skin and muscles of back
anterior branch
- known as
- function
- ventral ramus
- supplies anterior body wall and anterior surface
