Anatomy Chapter 14

cauda equina

Below L2, the vertebral canal is occupied by a bundle of spinal never roots called

adipose tissue

Between the dura mater and vertebral bone, one is most likely to find

efferent fibers

Carry motor signals from the CNS to effectors

Afferent fibers

Carry sensory signals from receptors to the CNS

Lateral corticospinal tract - large pathway in lateral funiculus. •Anterior corticospinal tract - small pathway in anterior funiculus.

Corticospinal tracts carry signals for precise limb movements from motor cortex (upper motor neurons).

Sacral

Motor innervation of leg proper comes predominantly from the ________ plexus.

central pattern generators

Neural circuits called _________ in the spinal cord produce the rhythmic muscular contractions of walking

Decussation

The anatomical crossing over of neurons from left to right

The obturator nerve

The brachial plexus gives rise to all the following nerves except

Spinocerebellar

The cerebellum receives feedback from the muscles and joints by way of the _____ tracts of the spinal cord.

Tibial and common fibular

The sciatic nerve is a composite of 2 nerves the ___________ and ____________

This tract contains second order neurons sensing pain and temperature from contralateral sensory neurons.

The spinothalamic tract ascends in the anterior and lateral funiculi to end in the thalamus.

ganglion

cluster of nerve cell bodies outside the CNS

functions of spinal cord

conduction-sensory information ascends, motor commands descend, neural integration;processing of information from diverse sources, locomotion: central pattern generators coordinating simple repetitive movement,reflexes

gray matter

contains mostly unmyelinated fibers and cell bodies, posterior and anterior horns, 2 lateral horns within thoracic and lumbar region

medullary cone

cord tapers to a point inferior to lumbar sacral enlargement

1st, order neurons

detect stimulus and transmit signal to spinal cord or brainstem

visceral fibers

innervate blood vessels, glands, and viscera

special fibers

innervate more localized organs in the head, including the eyes, ears, olfactory and taste receptors, and muscles of chewing, swallowing, and facial expression

general fibers

innervate widespread organs such as muscles, skin, glands, viscera, and blood vessels

cauda equina

innervates the pelvic organs and lower limbs

Lumbar

lower back

polysynaptic

many spinal reflexes employ ______________ reflex arcs

white matter

myelinated axons, 3 pairs of funiculi containing tracts (fasciculi)

Cervical

neck

Contralateral

on the opposite side of the body

Ipsilateral

on the same side of the body

ipsilateral reflex

sensory input and motor output on same side

contralateral reflex

sensory input from opposite side as motor output

intersegmental reflex

sensory signal in one level; motor output at a higher or lower level

•Gracile fasciculus - from lower body. •Cuneate fasciculus - from upper body.

Two tracts ascend within each posterior funiculus to end in the medulla.Both of these posterior funiculus tracts contain first order neurons sensing body position, discriminative touch, and pressure on the same side of the body. (Ascending tracts)

Pelvic

Which of these is not a region of the spinal cord?

The vestibulospinal tract

Which of these tracts carries motor signals destined for postural muscles?

Brachial

arm

visceral reflexes

Glands, cardiac muscle, and smooth muscle Controlled by autonomic nervous system

The anterior horns

In the spinal cord, the neurosomas of the lower motor neurons are found in the:

somatic fibers

Innervate skin, skeletal muscles, bones, and joints

Brain

Many somatic reflexs involve the _________

Nerve

A bundle of nerve fibers

spinothalamic tract

A patient has a gunshot wound that a bone fragment to nick the spinal cord. The patient now feels no pain or temperature sensations from that level of the body down. Most likely the _____________ _________ was damaged.

central canal

A tiny channel found within the spinal cord and inferior medulla oblongata

They're monosynaptic

All somatic reflexes share all of the following except

Mixed

All spinal cords are ________ nerves?

Rami

Distal to the intervertebral foramen, a spinal nerve branches into a posterior and anterior _________.

posterior root

The _________ ganglion contains the neurosomas of neurons that carry sensory signals to the spinal cord

Ganglia

Outside the CNS, the neurosomas of neurons are clustered in swellings called ________.

phrenic

The _________ nerves arise from the cervical plexus and inner are the diaphragm

Components of a typical reflex arcs

Sensory receptor Sensory neuron Motor neuron -efferent nerve fibers

somatic reflexes

Skeletal muscles Controlled by somatic nervous system

Connection

Spinal somatic reflexes don't require a ___________ to the brain and still function even if the cervical spinal cord is severed

Decussation

The crossing of a nerve fiber or tract from the right side of the CNS to the left or vice versa is called ___________

Vertebral

The dura mater is set off from the __________ bone by the epidural space

Proprioception

The non visual awareness of the body's position and movement is called _______

Epineurium

The outermost connective tissue wrapping of a nerve is called

tract

a bundle or group of nerve fibers located within the brain or spinal cord

dermatone map

a diagram of the cutaneous regions innervated by each spinal nerve

flaccid paralysis

a state in which the muscles are limp and cannot contract

paresthesia

abnormal sensation of numbness and tingling without objective cause

sacral plexus

between hips

Fasiculus

bundle of muscle fibers

3rd order neuron

carries the signal the rest of the way to the cerebral cortex

quadriplegia

paralysis of all four limbs due to lesions above C5

hemiplegia

paralysis of one side of the body, due to brain injury on the opposite side

paralegia

paralysis of the lower part of the body due to lesions from T1—L1

Reflexes

quick and involuntary responses to environmental stimuli, instantaneous movement

2nd order neuron

receives the signals at the spinal synapse the crosses over to the contralateral side and delivers them to a synapse in the thalamus.

Coccygal

region of the coccyx (tailbone)

spastic paralysis

stiff and awkward muscle control caused by a central nervous system disorder

Perineurium

surrounds each fascicle

Endoneurium

surrounds one axon

Epineurium

surrounds the entire nerve

Meninges

three layers of connective tissue in which the brain and spinal cord are wrapped