Anatomy Chapter 12
What is the name of reflexes that affect the involuntary control of skeletal muscles and the withdrawal reflex is an example?
somatic reflexes
what reflexes occur in the nuclei of the spinal cord?
spinal reflexes
Motor and sensory information in spinal rami preganglionic and postganglionic fibers to structures of the thoracic cavity are called?
sympathetic nerve
Spinal Meninges true or false. the pia mater is highly vascular
true
true or false. Postural muscle generally have firm muscle ton and extremely sensitive stretch receptors
true
true or false. most activity of our nervous system is outside our awareness.
true
What is a large bundle of axons from several spinal nerves?
trunk
Where do the brachial plexus nerves originate from?
trunks and cords
The ---- is highly organized allowing effiecent function
Nervous System
How many coccygeal spinal nerves are there?
1
How many thoricac spinal nerves are there?`
12
Spinal Cord Functional Anatomy How many pairs of spinal nerves are in the spinal cord?
31
A typical spinal cord has how many pairs of spinal nerves, and where does the spinal cord end?
31; ends between L1 and L2
How many lumbar spinal nerves are there?`
5
How many sarcal spinal nerves are there?`
5
How many cervical spinal nerves are there?`
8
Which spinal nerves lacks a sensory branch to the skin?
C1
Shingles are caused by the ---- ---- virus
Caused by varicella-zoster virus
In the nervous system, only a fraction reaches our ----- -----
Conscious Awareness
In the nervous system, ----- priortizing and distributing information
Processing Centers
Spinal Meninges What separates the dura mater from the arachnoid mater?
a narrow subdural space
What is the name of reflexes that are learned rather than pre-established and are enhanced by repetition?
acquired reflexes
What does the lumbar plexus mostly innervate?
anterior and side surfaces
Gray Matter What horns contain somatic motor nuclei?
anterior gray horn
Spinal Cord in Cross Section What is the name of the deep groove along the anterior surface?
anterior median fissure
Spinal Meninges Pia Mater is bound to ?
Underlying Nervous tissue
sensory information from ventrolateral body surface, body wall structures, and limbs
Ventral Ramus
Spinal Meninges Pia Mater is a meshwork of?
Elastic and Collagen Fibers
Injury to which of the nerve plexuses would interfere with the ability to breathe?
cervical
Spinal Cord Functional Anatomy What supplies nerves to the shoulders and upper limbs in the spinal cord?
cervical enlargement
What are the major nerve plexuses?
cervical, brachial, lumber, and sacral
Spinal Meninges Dura Mater contains dense ----- oriented longitudinally
collagen fiber
Spinal nerve structure and distribution Connective tissue layers of a spinal nerve Epineurium is made of a dense network of ----- ----
collagen fibers
White Matter What are the areas of white matter on spinal cord sides called?
columns
Specific Rami What type of rami are present the thoracic and lumbar segments of the spinal cord and contain the axons of sympathetic neurons?
communicating rami
What is the name of reflex that involves motor and sensory responses on opposite sides of the body?
contralateral
What are smaller branches that originate in trunks?
cords
Spinal Meninges What are the spinal meninges continuous with?
cranial meninges and connective tissue
What type of nerves is the face monitored by?
cranial nerves
What reflexes occur in the nuclei of the brain?
cranial reflexes
What is an example of a contralateral reflex?
crossed extensor reflex
What is the clinical importance of the cutaneous nerve?
damage can be localized by testing sensory function in hand
Dermatome are clinically important to determine
damage or infection of spinal nerve or dorsal root ganglion
what is the difference between sensory nuclei and motor nuclei?
sensory nuclei receive and relay sensory information from peripheral receptors. motor nuclei issue motor commands to peripheral effectors
What is the space that contains areolar connective tissue, blood vessles, and protective adipose tissue and separates the dura mater and the vertebral canal?
epidural space
What are muscle spindles?
sensory receptors of the stretch reflex
What is a viral infection of the dorsal root ganglia that produces painful rashes caused by infected nerves?
shingles
Spinal Meninges Arachnoid Mater What is the function of cerebrospinal fluid?
shock absorber and diffusion medium. allows things to diffuse across
Spinal Meninges Arachnoid Mater What is the arachnoid membrane composed of?
simple squamous epithelium (arachnoid membrane)
What is an example of a reflex arc?
simple withdrawal reflex
Spinal nerve structure and distribution Connective tissue layers of a spinal nerve What is the outermost covering of a nerve?
epineurium
When a spinal reflex only occurs in one spinal segment it is called?
single segmental
Where do the somatic and visceral motor fibers of the dorsal ramus go?
skin and skeletal muscles of the back
What type of axons does the ventral root contain?
somatic and visceral motor neurons
Spinal Nerve Branches What doe the rami carry?
some carry visceral and motor fibers of the ANS thoracic and lumbar segments carry the sympathetic division (fight or flight) motor fibers
What are the three layers of connective tissue of a spinal nerve?
epineurium, perineurium, and endoneurium
Spinal nerve structure and distribution Connective tissue layers of a spinal nerve compartments that contain bundles of axons in the perineurium are called?
fasicles
Spinal Cord Functional Anatomy What is the name of the slender thread of connective tissue attaching conus medullaris to coccyx?
filum terminale
Describe a dermatome
specific bilateral region of the skin surface monitored by a single pair of spinal nerves
What are the specialized membranes that provide physical stability and shock absorption for the spinal cord?
spinal meninges
Spinal Cord in Cross Section What contains axons of both sensory and motor neurons?
spinal nerve
What is an example of a crossed extensor reflex
stepping on a tack
In the nervous system, Motor Centers directing responses to ---
stimuli
What is the reflex that provide automatic regulation of skeletal muscle length?
stretch reflex
Spinal Meninges Arachnoid Mater The arachnoid trabecular hangs down to create?
subarachnoid space
Where is the cerebrospinal fluid that surrounds the spinal cord located?
subarachnoid space
Sensory information What carries sensory information from visceral organs?
sympathetic nerve
Spinal Cord Functional Anatomy What is the conus medullaris?
tapered portion of the spinal cord below the lumbar enlargement
What happens in a cross extensor reflex?
flexor pulls injured body part away while the crossed extensor reflex keeps other body part straight and supports shifting weight
What are two examples of withdrawal reflexes?
flexor reflex and crossed extensor reflex
Spinal Cord Functional Anatomy How are the cervical vertebrae named?
for the vertebra they pass above
Spinal Cord Functional Anatomy How are the spinal nerves from thoracic to coccyx named?
for the vertebrae they pass below
muscle spindles are innervated by what motor neuron that alters tension in spindle and controls the sensitivity of the receptor
gamma motor neurons
What structure in gray matter contains axons that laterally cross the spinal cord?
gray commissures
Spinal Cord in Cross Section What matter surrounds the central canal and is dominated by cell bodies of neurons, neuroglia, and unmyelinated axons?
gray matter
Spinal Meninges What do the branching blood vessels within the meninges deliver?
oxygen and nutrients
What is an example of the stretch reflex?
patellar reflex
What does the brachial plexus innervate?
pectoral girdle and upper limbs
What areas do the lumbar and sacral plexuses innervate?
pelivic girdle and lower limbs
Spinal nerve structure and distribution Connective tissue layers of a spinal nerve What is the middle layer of the covering of a nerve and divides the nerve into compartments?
perineurium
What nerve innervates the diaphragmatic muscles and injury to this nerve can lead to problems with breathing?
phrenic nerve
Spinal Meninges what is the innermost layer of the spinal meninges>
pia mater
Denticulate Ligaments extend from ---- through the arachnoid to -----
pia mater dura mater
What are the 3 spinal meninges?
pia mater, arachnoid mater, and dura mater
walking and running are examples of what type of reflex?
polysynaptic
What type of reflexes involves at least one interneuron, one sensory neuron, and one motor neuron and produces more complex reflexes?
polysynaptic reflexes
Gray Matter What horns contain somatic and visceral sensory nuclei?
posterior gray horn
Spinal Cord in Cross Section What is the name of the shallow longitudinal groove on the posterior surface?
posterior median sulcus
What does the sacral plexus mostly innervate?
posterior surfaces
White Matter What column lies between the posterior gray horns and posterior median sulcus?
posterior white column
What are the stretch reflexes that help maintain upright posture?
postural reflexes
Spinal Nerve Branches What are spinal nerve branches called?
rami
Motor and sensory information in spinal rami communicating branches are called?
rami communicates
What is a reflex?
rapid, automatic responses to certain stimuli
When the body activates motor neurons to contract flexor muscle, while inhibitory interneurons keep extensor muscles relaxed, this is called?
reciprocal inhibition
What is a "wiring" of a single reflex from receptor to effector?
reflex arc
What do the motor command going to the peripheral effctors usually do?
remove or oppose a stimulus
reinforcement can increase?
response
In the nervous system, Input pathways are -----
routing sensations
in what plexus is the sciatic nerve located?
sacral
What is the longest and largest nerve in the body?
sciatic nerve
Explain the order info is carried in neural reflexes?
sensory fibers carry info from peripheral receptors to integration center in the CNS. Motor fibers carry motor commands to peripheral effectors
Gray Matter What nuclei receive and relay sensory information from peripheral receptors?
sensory nuclei
After injuring her back, 22-year-old Tina exhibits a positive Babinski reflex. What does this imply about her injury?
the higher centers or descending tracts may be damaged
Spinal Cord in Cross Section Where does sensory information enter the CNS in the Spinal Nerve?
through the dorsal root
Spinal Cord in Cross Section Where does motor information exit the CNS in the Spinal Nerve?
through the ventral root
What purpose does reflex testing serve?
to observe damage to spinal segments
White Matter bundle of axons relatively uniform in diameter, myelination, conduction speed, and functional type
tracts
Specific Rami What type of rami innervates structures in the lateral and anterior trunk as well as the limbs?
ventral ramus
Spinal Cord in Cross Section What contains axons of motor neurons extending into periphery to control somatic and visceral effectors?
ventral root
Where do the somatic and visceral motor fibers of the ventral ramus go?
ventrolateral body surface, structures of body wall, and limbs
What is the name of the reflex that controls or adjusts activities of smooth and cardiac muscle, glands, and adipose tissue?
visceral reflexes
A disease that damages myelin sheaths would affect which portion of the spinal cord?
white matter
Spinal Cord in Cross Section what matter contains large numbers of mostly myelinated and some unmyelinated axons?
white matter
indicate whether the following makes up the white or gray rami: preganglionic fibers connecting a spinal nerve with a sympathetic ganglion in the thoracic and lumbar region of the spinal cord
white rami
Motor and sensory information in spinal rami pregangionic fibers that are myelinated and go to the sympathetic ganglion are?
white ramus
When is the strongest withdrawal reflex triggered?
with painful stimuli
when body parts are moved away from a stimulus, what type of reflex is this?
withdrawal
White Matter What column lies between anterior gray horns and median fissure?
anterior white column
White Matter What interconnects anterior white columns?
anterior white commisure
Spinal Meninges What is the middle meningeal layer?
arachnoid mater
Spinal Meninges Arachnoid Mater A network of collagen and elastin fibers connecting the arachnoid mater to the pia mater is called?
arachnoid trabeculae
how did nerve plexuses originally develop?
as ventral rami that innervated small skeletal muscles during development then fused together
White Matter carries sensory information toward the brain
ascending tracts
Spinal nerve structure and distribution Connective tissue layers of a spinal nerve What structures do capillaries in the endoneurium layer provide for?
axons, schwann cells, and fibroblasts
How do reflexes preserve homeostasis?
by making rapid adjustments to organs or organ systems
How can brain influences affect spinal reflexes?
can facilitate or inhibit motor neurons or interneurons involved
Spinal Meninges Arachnoid Mater What does the subarachnoid space contain?
cerebrospinal fluid
Supporting Ligaments What supporting ligaments prevent lateral movement of the spinal cord?
denticulate ligaments
White Matter conveys motor commands to spinal cord
descending tracts
Why are dermatomes clinically important?
determine damage or infection of spinal nerve or dorsal root ganglion
Spinal Cord Functional Anatomy What structures make up the cauda equina?
doral and ventral roots, filum terminale
Specific Rami What type of rami innervates the muscles, joints, and skin of the back?
dorsal ramus
Sensory information What carries the sensory information to the spinal cord?
dorsal root
Spinal Cord in Cross Section What contains axons of neurons whose cell bodies are in the dorsal root ganglion?
dorsal root
The sensory neuron that surrounds the muscle fiber is always sending impulses to the CNS through the?
dorsal root
Spinal Cord in Cross Section What contains sensory neuron cell bodies, and is on each side of the spinal segment?
dorsal root ganglion
Spinal Meninges What is the outermost covering of the spinal cord?
dura mater
What ligaments prevent superior-inferior movements of the spinal cord?
dural ligaments at the foramen magnum and the coccygeal ligament
Spinal nerve structure and distribution Connective tissue layers of a spinal nerve What is the innermost layer of nerve covering?
endoneurium
indicate whther the following makes up the white or gray rami: postganglionic fibers connecting a sympathetic ganglion in the thoracic or lumbar region with the spinal nerve
gray rami
Motor and sensory information in spinal rami postganglionic fibers that are unmyelinated and innervate the glands and smooth muscles of body wall or limbs are?
gray ramus
Describe the composition of the gray matter of the spinal cord
has cell bodies of neurons, neuroglia, and unmyelinated axons. Surrounds the central canal and is shaped like a butterfly
Gray and White Matter In gray matter what is the name of the projections toward the outer surface of the spinal cord?
horns
A person who has polio has lost the use of his leg muscles. In which area of his spinal cord would you expect the virus-infected motor neurons to be?
in the descending tracts of the white matter
where is a lumbar puncture inserted?
in the subarachnoid space below L3 vertebra or tip of the conus medullaris
Spinal nerve structure and distribution Connective tissue layers of a spinal nerve what does the endoneurium tissues surround?
individual axons
What are connections formed between neurons genetically or developmentally programmed?
innate reflexes
When a spinal reflex occurs in multiple spinal segments it is called?
intersegmental
muscle spindles consist of a bundle of specialized muscle fibers called?
intrafusal muscle fibers
What is the name of reflexes that are on the same side?
ipsilateral
the stretch reflex is an example of which type of reflex?
ipsilateral
what happens when a spinal reflex is facilitated?
its reinforced
Gray Matter What horns are only in the thoracic and lumbar segments and contains visceral motor nuclei?
lateral gray horns
White Matter What column lies on either side between anterior and posterior gray horns?
lateral white column
Explain the cause of shingles
lies dormant in the anterior gray horns of the spinal cord after someone has had chicken pox and attacks neurons within the dorsal roots of spinal nerves and sensory ganglia of cranial nerves
Spinal Cord Functional Anatomy What supplies nerves to the pelvis and lower limbs in the spinal card?
lumbar enlargement
Spinal Meninges Arachnoid Mater How is cerebrospinal fluid withdrawn from the body?
lumbar puncture
What type of reflex is the simplest reflex arc involving one snesory and one motor neuron and has a faster response time?
monosynaptic reflexes
Gray Matter What nuclei issue motor commands to peripheral effectors?
motor nuclei
the withdrawal reflex is an example of what type of feedback?
negative
What is a complex interwoven network of nerves?
nerve plexus
Gray Matter In gray matter what are cell bodies called?
nuclei