Chapter 14 QS Anatomy (Spinal Cord & Spinal Nerves)

The cell bodies of sensory neurons are found

in posterior root ganglia.

Motor signals to maintain posture and balance pass through a(n) ____________ pathway.

indirect

Touching a hot object with the right hand will result in withdrawl of the right hand from the object. This is an example of a(n) ____________ reflex.

ipsilateral

Match the region of the spinal cord with the number of spinal nerve pairs that are associated with it.

Cervical=eight Lumbar=five Coccygeal=one Thoracic=twelve

Which of the following statements is correct about spinal nerves?

The posterior root is sensory.

The smaller structural units that contain bundles of axons within each white matter funiculus are called

tracts

A spinal nerve splits into ___ branches.

two

Which meninx is the deepest in its location?

pia mater

Which neuron in a sensory pathway is part of the sensory receptor?

primary

The __________ enlargement of the spinal cord is the location where nerves that supply the upper limbs enter and leave the spinal cord, and the __________ enlargement is the location where nerves that supply the lower limbs enter and leave the spinal cord.

cervical; lumbosacral

Direct motor pathways are involved in

consciously contracting skeletal muscle.

The area of the skin that is supplied with sensory innervation by a pair of spinal nerves is called a ___________.

dermatome

A command from the brain to signal muscle contraction would pass through a(n)

descending pathway.

Damage to the ____________ nerve may result in difficulty extending the knee as in kicking a ball.

femoral

The spinal cord extends from the level of the _______________ to the level of the ____________.

foramen magnum; first lumbar vertebra

The spinal cord is partitioned into an inner __________ matter region and an outer ___________ matter region.

gray; white

Each thoracic spinal nerve emerges from intervertebral foramen that is _____ to the vertebra of the same number.

inferior

What structures develop from the basal plates during embryonic development? Check all that are correct.

-Anterior and lateral horns of gray matter -Anterior part of gray commissure

Check all that are components of a monosynaptic reflex arc.

-Sensory receptors -Motor neurons

Select all that are part of the brachial plexus.

-Superior, middle, and inferior trunks -Anterior and posterior divisions -Anterior rami -Posterior, medial, and lateral cords

Choose the accurate statement(s) regarding the general anatomy of the nerve plexuses. Check all that apply.

-The posterior cord of the brachial plexus is formed by three posterior divisions. -The cervical plexus receives fibers from the anterior rami of nerves C1 to C5.

A neuron associated with the skin is damaged and cannot transmit information as part of a sensory pathway. Select all that are true.

-The soma of the damaged neuron is near the spinal cord.

Select all that are true of motor pathways.

-They are composed of at least two neurons. -Axons of lower motor neurons innervate skeletal muscle cells.

Select all that are true of sensory pathways.

-They are composed of primary, secondary, and sometimes tertiary neurons. -They are also called ascending pathways. -They relay information from sensory receptors.

Select all that are common to most spinal conduction pathways.

-They decussate at some level of the spinal cord. -Each tract has a matching tract on the other side of the CNS. -Cell bodies of neurons are located within nuclei associated with each pathway.

Select all that are true of the intercostal nerves.

-They innervate the intercostal spaces. -They may include sensory fibers from the skin and chest wall. -They include motor fibers that innervate skeletal muscle.

Rhythmic oscillations between flexion and extension when the muscle reflex is tested are called ____________.

clonus

Select all that are locations of gray matter in the spinal cord.

-Anterior horn -Lateral horn -Posterior horn -Gray commissure

Select all that may be included in motor pathways.

-Cerebral cortex -Cerebellum -Cerebral nuclei

Check all that are true statements regarding dermatomes.

-Dermatomes are involved in referred visceral pain. -If a person experiences damage or infection in an internal organ, the pain may be experienced elsewhere due to dermatomes.

Select all that are true of the obturator nerve.

-It innervates adductors of the thigh. -It passes through the obturator foramen of the os coxae. -It contains sensory fibers.

Select all the pathways where pressure receptors from the skin may send their sensory information.

-Posterior funiculus-medial lemniscal -Anterolateral -Spinocerebellar

There are ___ pairs of spinal nerves that exit the vertebral column.

31

The left and right cervical plexuses are formed primarily by the anterior rami of spinal nerves

C1-C4.

Match the number of the spinal nerve with its location.

C3=Cervical plexus L2=Lumbar plexus S3=Sacral plexus

The eighth spinal nerve exits the intervertebral foramen between the ______ vertebrae.

C7 and T1

A conduction pathway in the spinal cord consists of a single sensory neuron and a single motor neuron.

False

A nerve plexus is a network of interweaving posterior rami of spinal nerves.

False

A reflex arc must involve interneurons for processing in the spinal cord.

False

A spinal nerve is classified as motor or sensory, depending on the type of fibers it contains.

False

Motor pathways are ascending pathways in the brain and spinal cord that control effectors.

False

Somatosensory pathways process stimuli from organs like the heart, stomach, and small intestine.

False

White matter in the spinal cord is found surrounding the gray matter as well as within the lateral horns.

False

Match the type of abnormal reflex with its description.

Hypoactive reflex=Reflex response is diminished or absent Hyperactive reflex=Reflex response is abnormally strong

The central nervous system forms primarily from which of the following?

Neural tube

Most of the thoracic spinal nerves, as well as nerves ________, do not form plexuses.

S5-Co1

Which nerve of the sacral plexus is the largest and longest nerve in the body?

Sciatic nerve

Match the component of gray matter in the spinal cord with its description.

Serves as a communication route between left and right sides=gray commissure Houses cell bodies of autonomic motor neurons=lateral horns Houses cell bodies of somatic motor neurons=anterior horns Houses axons of sensory neurons and cell bodies of interneurons=posterior horns

Intercostal nerves are the anterior rami of which spinal nerves?

T1-T11

Match the type of reflex with its description.

The simplest reflex; muscles contract in response to a stretch=stretch reflex Prevents contracting muscles from applying tension to tendons=golgi tendon reflex Removes a body part from a painful stimulus=withdrawal reflex Response to a withdrawal reflex; causes extension of the opposite limb=crossed-extensor reflex

Why does the vertebral canal extend beyond the spinal cord, encompassing the cauda equina?

The vertebral column outgrows the spinal cord during development.

How many neurons are in the somesthetic pathway from the skin to the postcentral gyrus?

Three

All reflexes share the property of being an involuntary response.

True

During development, the growth of the vertebrae continues for longer than the growth of the spinal cord itself.

True

Some sensory pathways process stimuli from the viscera.

True

The anterior rami of two lumbar spinal nerves help form the sacral plexus.

True

The cervical plexuses are composed primarily of C1-C4, and its branches innervate the skin and muscles of the anterior neck.

True

The lumbar plexus can be divided into anterior and posterior divisions.

True

The spinal cord exhibits some functional independence from the brain such as the reflexes it controls.

True

There are 31 pairs of mixed nerves that emerge from the spinal cord.

True

There are eight pairs of cervical spinal nerves, but only seven cervical vertebrae.

True

Upper motor neurons may inhibit lower motor neurons.

True

Nerve plexuses are organized such that axons from each ________ ramus extend to body structures through several different branches.

anterior

Motor neurons contain their cell bodies in the ______ and axons in the ______.

anterior horn; anterior root

After an injury, a patient has difficulty contracting his deltoid muscle. This indicates possible damage to the ___________ nerve.

axillary

The cords of the brachial plexus are named by their location with respect to the

axillary artery.

Which portion of a reflex arc is most likely to be located entirely within the central nervous system?

interneuron

Severing the posterior ramus of a spinal nerve may result in

losing feeling from the skin of the back.The __________ enlargement of the spinal cord is the location where nerves that supply the upper limbs enter and leave the spinal cord, and the __________ enlargement is the location where nerves that supply the lower limbs enter and leave the spinal cord.

The spinal cord and spinal nerves are responsible for _______, which are our quickest reactions to a stimulus.

reflexes

Tapping the triceps brachii muscle tendon will result in reflexive elbow extension. This is an example of a ____________ reflex.

stretch

The space containing cerebrospinal fluid is the _________ space.

subarachnoid