Anatomy- Ch 13 Spinal Cord/Spinal Nerves & Somatic Reflexes
The denticulate ligaments are extensions of which meninx?
Pia mater
Which meninx is closly associated w/ contorus of vertebrae?
Pia mater
Which ramus of a spinal nerve innervates the local muscles, joints, & skin of the back?
Posterior
What is an afferent fiber?
Sensory Nerve Fiber
What are 4 possible effectors of a reflex?
cardiac muscle gland smooth muscle skeletal
What rami of spinal nerves T1-L2 connect to the sympathetic chain ganglia?
communicates rami
Which rami connects the anterior rami to the sympathetic chain?
communicating
The anterior horns of the spinal cord contain somas of what neurons?
somatic motor neurons
Whta effect does severing a sensory root that innervartes a drmatome have?
some sensation remains
What is the subarachnoid space?
space b/t arachnoid mater & pia mater
Which are properties of a reflex?
stimulationn stereotyped quick involuntary
Where does CSF circulate?
subarachnoid space
What is a muscle spindle?
type of stretch receptor embeded in the skeletal muscle
In descending pathways, which motor neurons have their somas in the cerebral cortex or brain stem?
upper
What neurosn have their somas in the cerebral cortex or brainstem?
upper motor
Somatic Receptors
use receptros locarted in the skin, muscle , & tendon
# of neurons in a descending pathway?
2
How many neurons are in an ascending pathway b/t receptor & brain?
3
How many spinal nerves there in order from superior to inferior?
8 cervical 12 thoracic 5lumbar 5 sacral 1 coccygeal
First cervical spinal nerve emerge above vertebrae?
C1
What nerve is a peripheral nerve carrying nerve signals to CNS?
Sensory Nerve
First cervical spinal nerve emerges b/t which 2 structures?
Skull & vertebrae C1
Which is a somatosensory stimulus?
TOuch stretch Temp pain pressure
In CNS, bundles of axons that make up white matter are called what?
Tracts
Which ramus of a spinal nerve innervates & lateral skin & muscles of the truck
anterior
What rami & spinal nerves arise from the intercoastal?
anterior; thoracic
What is the dural sheath around the spinal cord formed from?
dura mater
The DICT eclosing an entire nerve
epineurium
In desdending tracts, which motor neuron innervates the target organ?
lower
In descending pathways, the upper motor neurons synapse with whidh neurons in the brainstorm or spinal cord?
lower motor
Ascending tract in the spinal cord will carry what info to the brain?
sensory
The somas of which neurons are found within the posterior root ganglion?
sensory
What type of a neuron has the soma located in the posterior root ganglion?
sensory neuron
Meninges
series of fibrous CT covering the CNS
Arachnoid Layer
several layers of squamos cuboidal cells with loose mesh fibers in space below
What disease results from herpes virus residing in a posterior root ganglian?
shingles
How manyn pair of spinal nerves are there?
31 pairs
The _____ horsw of the spinal cord contain the cell bodies of outgoing somatic motor neurons.
Anterior
Where does the spinal cord arsise from the medulla oblongata?
At the foramen magnum
Which is the name of a plexus?
Brachial Cervical Lumbar Sacral
Regions of the spinal cord?
Cervical Thoracic Lumbar Sacral
Spinal cord region in order
Cervical Thoracic Lumbar Sacral
The anterior rami of spinal nerves form which nerve plexuses?
Cervical, lumbar, sacreal
Functions of the spinal cord?
Condcution Locomotion Reflexes
Which tract will have orgigin & destination on opposite sides of bod?
Contralateral
What is an area of skin innervated by a spinal nerve called?
Dermatome
Within the spinal cord. which tracts carry motor signals down from the brain?
Descending
T/F: Severing a sensory nerve root will completely deaden sensation from a dermatome.
False
What is a cluster of a neuron cell bodies located outside of the CNS called?
Ganglion
Where are the neurons cell bodies, dendrites, & synapsese found in the CNS?
Gray mater
What is the site of synaptic integration in the spinal cord?
Gray matter
In an adult where does the spinal cord end?
L1
A special fiber innervates what in the body?
Lcalized organs in te head (eyes, eaar, olfactory, tase receptors)
What indicatese the end of the spinal cord?
Medullary Cone
The anterior root of a spinal nerve contain axons of which neurons?
Motor
Visceral Fibers
Nerve fibers that innervate BV, glands, & internal organs
What are 3 columns of what matter found in the spinal cord?
Posterior column Anterior column Lateral column
Components of a reflex arc in order
Receptor Afferent Nerve Fiber Integration center Efferent Nerve Fiber Effector
Which of these structures is closest to the spinal cord?
Rootlet
Nerve fibers of periphereal nerves are encased in which cells?
Schwann
The coccygela ligament is formed from the fusion of which 2 structers?
Terminal filum & dura mater
A generla fiber innervates what?
Widespread organs such as muscles, skin, glands, visceria, BV
Nerve fiber refers to what of a neuron?
axon
What is the gray commissure of the spinal cord?
band of gray matter connecting the gray matter of the L side to the R
What is the cauda equina?
bundle of nerve roots occupying the vertebral canal L2 - S5
What enlargement of thspinal cord gives rise to the nerves of the upper limbs
cervical enlargement
What area of skin is innervated by spinal nerve?
dermatome
Mater of brain in order from superficial layer
dura mater arachnoid mater pia mater
external to the neurilemma of a nerve fiber is a loose layer of CT surrounding a nerve fiber is called what?
endoneurium
With in a nerve, nerve fibers are gathered into bundles called?
fascicles
Which stimulus causes a muscle to reflexively contract?
increased strech
Which spinal cord areas are composed of gray matter?
lateral horn anterior horn posterior horn
Central Canal
lined w ependymal cells & contains cerebrospinal fluid (CSF)
posterior median sulcas
longitudinal groove on the dorsal surface of the spinal cord
What is the anterior median fissure of the spinal cord?
longitudinal groove on the ventral surface of the spinal cord
What branch of the spinal nerve innervates the meninges?
meningeal branch
The pollipvirus destroys which neurons in the brain steam & anterior horn of the spinal cord?
motor
Which of the following desrcibes a sensory nerve?
nerve containing only fibers carrying incoming nerve signals to the CNS
Monosynaptic
reflex containing only 1 synapse b/t neurons
What tract carries signals that control muscles of the upper and lower limbs for posture and balance?
reticulospinal tract
Moving peripherally from the spinal cord, which anterior & posterior structures form a spinal nerve?
roots
Somatic nerve fiber innervates which of the following?
skin, skelteal muscles, bones & joints
, where is the white matter in relation to the gray matter?
superficial
Intercoastal arise from the anterior rami of the _______ spinal nerves.
thoracic
Which are considered a distal branch of a spinal nerve?
Anterior ramus Posterior ramus
All spinal nerves except C1 pass through what structure to emerge from vertebral column?
Intervertebral foramen
_______ muscle fibers are modified muscle fibers with in a muscle spindle.
Intrafusal
Which tract will have its origin & destination on the same side of body?
Ipsilateral
The communicating rami connect to the anterior rami to which of the following?
The sympathetic chain
Nerve
a cordlike organ composed of numerous nerve fibers (axons) bound together by connective tissue
Posterior root of a spinal nerve carries _______ nerve fibers
afferent
What is the lumbar enlargement of the spinal cord?
area of spinal cord that gives rise to nerves of the lower limbs + pelvis
What factor accounts for the fact that the R side of brain communicates with the left side of body?
decussation
What is the epineurium, composed of?
dense irregular connective tissue
What happens to motor neurons of the lateral regios of the spinal cord when amyotrophic lateral sclerosis?
destroyed sclerosis
Which describes a motor nerve?
nerve containing only fibers carrying outgoing nerve signals from the CNS
Within a nerve, each fascicle is wrapped in a layer called a ________
perineurium
Which spinal nerve roots carry sensory nerve signals?
posteior
Reflex
quick, involunatry, stereotped responses to a stimulus
Fasciculus
tract of nerve fibers with in a column of the spinal cord.