Exam #4 Chapter 13 Flashcards
- specific purposes of the _____:
- rapid responses: neural circuits that do not involve the brain allow for reflexive actions to occur
- integration zone for EPSP’s and IPSP’s
- deliver sensory information to the brain, and motor output to muscles
spinal cord
-3 protective structures of the spinal cord: _____, _____, and _____
vertebral column
meninges
CSF
-3 protective connective tissue coverings encircling the brain and spinal cord
meninges
-the spinal cord is also protected by a cushion of fat and connective tissue located in the _____, a space between the dura mater and the wall of the vertebral canal
epidural space
-the meninges from superficial to deep are: _____, ____, and _____
dura mater
arachnoid mater
pia mater
- literally, tough mother, the most superficial layer
- thick dense irregular connective tissue
- continuous with the epineurium, the outer covering of the spinal and cranial nerves
dura mater
- the middle portion
- thin, avascular, composed of cells, collagen and elastic fibers
arachnoid mater
- the innermost layer
- thin, transparent layer, adheres to surface of spinal cord and brain
- highly vascular, supplies oxygen and nutrients
pia mater
-between the dura and arachnoid is a thin _____ filled with interstitial fluid
subdural space
-between the arachnoid and pia is the _____, which contains CSF
subarachnoid space
-triangular shaped extensions of the pia mater called _____ suspend the spinal cord in the dural sheath
denticulate ligaments
- roughly oval in shape, being flattened slightly anteriorly and posteriorly
- in adults it extends from the medulla oblongata, the inferior part of the brain, to superior border of the second lumbar vertebra
- in newborns, it extends to the 3rd and 4th lumbar vertebra
spinal cord
-the location of the _____ of the body is why its enlargements of the spine
plexi
- the superior enlargement
- C4 to T1, where nerves to and from upper limbs arise
cervical enlargement
- the inferior enlargement
- T9 to T12, nerves to and from lower limbs
lumbar enlargement
-between L1 and L2, tapering cone-shaped end of spinal cord
conus medullaris
-extension of pia mater, fuses with arachnoid and dura, anchors spinal cord to coccyx
filum terminale
- 2 bundles of axons
- posterior =sensory
- anterior =motor
roots
-swelling, contains cell bodies of sensory neurons
posterior root ganglion
- the paths of communication between the spinal cord and specific regions of the body
- the spinal cord appears to be segmented b/c the 31 pairs of ____ emerge at regular intervals from intervertebral foramina
spinal nerves
-horse’s tail, roots of lower spinal nerves
cauda equina
-extends all the way to the 4th ventricle of the medulla oblongata, filled with CSF
central canal
-functional groups, clusters of neuronal cell bodies (sensory/motor)
nuclei
-3 regions of grey matter = _____
horns
-consists of axons of sensory neurons and interneurons
posterior horn
-consist of somatic motor nuclei
anterior horn
- only in thoracic and upper lumbar sections, autonomic motor nuclei
- not always there, on anterior side
lateral horn
-white matter organized into _____, columns of axons carrying similar info
tracts
- bundles of axons in the PNS = _____
- in the CNS it = _____
nerves
tracts
-spinal nerves are mixed nerves because ?
they contain both sensory and motor axons
- ascend directly via sensory tract in white matter
- ascend directly via interneuron tract in white matter
- in both cases, the descending tract may return an output signal
3. connect to motor neuron via interneuron, skipping additional integration by the brain (reflex)
3 pathways for incoming sensory information
-the motor descending tract does not need the _____ to make decisions
brain
-the epineurium, perineurium, and the endoneurium are the anatomy of a _____
spinal nerve
- inner most layer
- has fibroblasts and macrophages
endoneurium
-groups of axons with their endoneurium are held together in bundles called _____, each wrapped in _____
fascicles
perineurium
- the middle layer
- thicker layer of connective tissue
perineurium
- the outer most covering
- fuses with dura mater at intervertebral foramen
epineurium
-axons from the rami of spinal nerves form a network with adjacent nerves
plexus
-5 plexuses are ____, _____, _____, _____, and _____
cervical
brachial
lumbar
sacral
coccygeal
-the cervical plexus is from __ to __
C1 to C5
-the brachial plexus is from __ to __
C5 to T1
-the lumbar plexus is from __ to __
L1 to L4
-the sacral plexus is from __ to __
L4 to S4
-the coccygeal plexus is from __ to __
S5 to S5 much smaller
-the anterior rami of spinal nerves T2 to T12 do not enter into the formation of plexuses and are known as _____
intercostal nerves or thoracic nerves
-a short distance after passing through its intervertebral foramen, a spinal nerve divides into several braches called _____
rami
- head and shoulders are part of the _____ of the cervical plexus
- sensory function
superficial sensory branches
-the neck and postural muscles are part of the ____ of the cervical plexus
deep motor branches
-innervates the diaphragm, controls breathing, from C3 to C5
phrenic nerve
- C5 to T1, part of brachial plexus
- most forearm flexors, some muscles of hand
- skin of hand and fingers
median nerve
- C5 to T1, part of the brachial plexus
- forearm extensors, skin of posterior arm, hands and fingers
radial nerve
- C8 to T1, part of brachial plexus
- flexor carpi ulnaris
- most muscles of hand, skin of hands and fingers
ulnar nerve
-provides almost all nerves of shoulder and upper limbs
brachial plexus
-sensory function: anterior lower limbs and genitals
lumbar plexus
- L2 to L4, of lumbar plexus
- hip flexors and knee extensors, skin over thigh and medial leg/foot
- kick nerve
- additional motor functions: anterolateral abdominal wall, hip adductors
femoral nerve
-sensory: posterior lower limbs and genitals
sacral plexus
- L4 to S3 of sacral plexus
- has two nerves, tibial and common fibular
- they are bound by connective tissue, innervates hamstrings and then splits below the knee
sciatic nerve
- L4 to S3 of sacral plexus
- gastrocnemius and other muscles of plantar flexion and toe flexion
tibial nerve
- L4 to S2 of sacral plexus
- tibialis anterior and muscles of dorsiflexion, toe extension
common fibular
-is a fast, involuntary, unplanned sequence of actions that occurs in response to a particular stimulus
reflex
- the pathway followed by nerve impulses that produce a reflex is a _____
- protection, used for speed response
reflex arc
- sensory receptor
- sensory neuron
- integrating center
- motor neuron
- effector
-these are the 5 functional components of the _____
reflex arc
-integration occurs in the _____ and _____
cranial reflex and spinal reflex
-when integration occurs in the brainstem
cranial reflex
-when integration occurs in the spinal cord grey matter
spinal reflex
-the effectors of the reflex are _____ and _____
somatic reflexes and autonomic (visceral) reflexes
-effector that contracts skeletal muscles
somatic reflexes
-effectors that are smooth or cardiac muscles, and glands
autonomic (visceral) reflexes
-the _____ and _____ are the synapses of the CNS
monosynaptic and polysynaptic
-a reflex pathway having only one synapse in the CNS
monosynaptic reflex arc
-involves more than two types of neurons and more than one CNS synapse
polysynaptic reflex arc
-the nerve impulses travel either _____ or _____
ipsilateral or contralateral
- sensory input enters the same side of the SC that the motor output leaves
- all monosynaptic reflexes
ipsilateral reflexes
-sensory and motor on opposite sides
contralateral reflexes
- contraction of a skeletal muscle (the effector) in response to stretching of the muscle
- monosynaptic and ipsilateral
stretch reflex
-small degree of contraction present while the muscle is at rest
muscle tone
- operates as a feedback mechanism to control muscle tension by causing muscle relaxation before muscle force becomes so great the tendon tears
- polysynaptic and ipsilateral
tendon reflex
- polysynaptic, ipsilateral reflex
- the withdrawal reflex, in response to a painful stimulus
flexor reflex
- helps you maintain balance in response to a painful stimulus
- polysynaptic , contralateral reflex
crossed extensor reflex
- when light is shined in one eye and both eyes in response pupils constrict
- polysynaptic, ipsilateral, and contralateral
autonomic cranial reflex
- a region of the skin that sends sensory info to the CNS vía a single pair of spinal nerves
- they are helpful in diagnosing nerve damage due to their very well defined sensory regions
dermatome
