Exam 4 Chapter 13 HW + Study Guide

Arrange the spinal meninges from innermost layer to outermost layer.

pia mater, arachnoid mater, dura mater

These structures extending from the pia mater through to the dura mater support the spinal cord by preventing lateral movement.

denticulate ligaments

Spinal nerves are

both sensory and motor

If the posterior root of a spinal nerve is severed,

Sensory input would be blocked

A posterior and anterior root of each spinal segment unite to form a

spinal nerve.

Blood vessels that supply the spinal cord run along the surface of the

Pia mater

The condition in which a person loses all feeling and movement of the arms and legs due to spinal cord injury is termed

quadriplegia.

During the procedure known as a(n) ________, a needle is inserted into the subarachnoid space in the inferior lumbar region.

lumbar puncture

     Tom is a football player who gets hit hard from behind along his spine. About a week later, he is diagnosed with bacterial meningitis, an infection of the CSF carried through the bloodstream. Given that the infection was associated with blood, which hypothesis is most likely to have occurred?  

   The pia matter tore away from the spinal cord, damaging the associated blood vessels, which leaked into the subarachnoid space.  

Bundles of axons in the central nervous system are known as

tracts

In the spinal cord, white matter is separated into ascending and descending tracts organized as

columns

Axons crossing from one side of the spinal cord to the other within the gray matter are found in the

gray commissures

Where do somatic motor neurons reside?

The biggest part

The six projections from the gray matter seen in cross-sections of the spinal cord are called __________.

horns

The __________ gray horns contain somatic and visceral sensory nuclei.

posterior

The outermost connective tissue covering of nerves is the

epineurium

Preganglionic and postganglionic fibers of the autonomic nervous system that innervate internal organs are collectively called

sympathic nerves

A viral disease that destroys the cells of the anterior gray horn will

bills, lead to skeletal muscle weakness or paralysis.

The complex, interwoven network formed by contributions from the anterior rami of neighboring spinal nerves is termed a(n)

plexus

The layer of connective tissue that surrounds individual axons within a peripheral nerve is termed the

endoneurium.

You are sitting at a Mexican restaurant waiting for your food. The waiter brings a very hot plate, telling you to be careful about touching it. You touch it anyway, producing a pain sensation in your fingers, a withdrawal of your hand, and an auditory comment of what you are thinking. This scenario represents a ________ neuronal circuit.

parallel processing

In ________, one neuron synapses on several postsynaptic neurons.

divergence

A motor neuron typically receives input from neurons that originate in various areas of the brain. This type of circuit is a

convergent circuit

Which of the following is not a way that reflexes are classified?

sympathetic/parasympathetic

All of the following are true of neural reflexes except that they

cannot be modified by the brain

The neural "wiring" of a single reflex is called a(n)

Reflex Arc

 A reflex that leads to secretion of saliva is a(n) __________ reflex.    

visceral

The reflex that prevents a muscle from exerting too much tension is the ________ reflex.

tendon

Spinal interneurons inhibit antagonist motor neurons in a process called

reciprocal inhibition.

Reflexes that activate muscles on the same side of the body as the stimulus are called

ipsilateral.

Four spinal cord regions from superior to inferior:

Cervical, Thoracic, Lumbar, Sacral.

Fluid in the central canal and subarachnoid space:

Cerebrospinal fluid (CSF).

Body parts served by cervical and lumbar enlargements:

Cervical enlargement: Upper limbs.

Lumbar enlargement: Lower limbs.

Contents of dorsal root ganglia:

cell bodies of sensory neurons

Function of dorsal roots and ventral roots:

Dorsal roots: Carry sensory (afferent) fibers into the spinal cord.

Ventral roots: Carry motor (efferent) fibers out of the spinal cord.

Dorsal roots:

Carry sensory (afferent) fibers into the spinal cord.

Ventral roots:

Carry motor (efferent) fibers out of the spinal cord.

Function of rami communicantes:

Connect spinal nerves to the sympathetic chain (sympathetic nervous system).

White ramus:

Myelinated preganglionic sympathetic axons.

Gray ramus:

Unmyelinated postganglionic sympathetic axons.

Spinal nerves as mixed nerves:

Contain both sensory and motor fibers.

Location for a spinal tap:

Typically performed in the lumbar region (lower back), below the end of the spinal cord.

Definition of meningitis:

Inflammation of the meninges (protective membranes) surrounding the brain and spinal cord.

Structures mainly found in gray matter

Neuron cell bodies, dendrites, and unmyelinated axons.

Structures mainly found in white matter:

Myelinated axons.

Organized areas of spinal cord gray matter called:

Nuclei

Function of sensory nuclei and motor nuclei in the spinal cord:

Sensory nuclei: Receive and relay sensory information.

Motor nuclei: Send motor commands to peripheral effectors (muscles and glands).

Organized areas of spinal cord white matter called:

Tracts or columns.

Type of information carried by ascending tracts and descending tracts:

Ascending tracts: Carry sensory information towards the brain.

Descending tracts: Carry motor commands from the brain to the spinal cord.

Location of epineurium on a typical peripheral nerve:

Outermost layer covering the entire nerve.

Location of endoneurium on a typical peripheral nerve:

Innermost layer surrounding individual axons.

Location of perineurium on a typical peripheral nerve:

Middle layer surrounding bundles of axons (fascicles).

Definition of a dermatome:

Area of skin supplied by a single spinal nerve.

Definition of a nerve plexus

Network of intersecting nerves.

4 nerve plexuses

Cervical, Brachial, Lumbar, Sacral.

Cervical plexus nerve innervating the diaphragm:

Phrenic nerve.

Damage to this nerve can impair breathing (diaphragm paralysis).

Nerves causing carpal tunnel syndrome belong to which plexus:

Brachial plexus.

Sciatic nerve belongs to which plexus:

Sacral plexus.

CNS neurons organized into functional groups called neuronal pools:

Interneurons.

Five neural circuits and their functions:

1. Diverging circuit: One input, many outputs (amplification).

2. Converging circuit: Many inputs, one output (decision-making).

3. Reverberating circuit: Feedback loop (repeated rhythmic activity).

4. Parallel after-discharge circuit: Imprecise timing of output (complex motor activities).

5. Serial processing: Stepwise information processing (specific response).

Diverging circuit:

One input, many outputs (amplification).

Converging circuit:

Many inputs, one output (decision-making).

Reverberating circuit:

Feedback loop (repeated rhythmic activity).

Parallel after-discharge circuit:

Imprecise timing of output (complex motor activities).

Serial processing:

Stepwise information processing (specific response).

Definition of a neural reflex:

Rapid, automatic response to a stimulus.

Five steps of a simple neural reflex arc:

Receptor, sensory neuron, integration center, motor neuron, effector.

Difference between innate and acquired reflexes:

Innate reflexes: Genetically programmed (e.g., withdrawal reflex).

Acquired reflexes: Learned (e.g., driving a car).

monosynaptic reflex:

Involves only one synapse between sensory and motor neuron.

Polysynaptic reflex:

Involves multiple synapses and interneurons.

Is the patellar reflex that is a stretch reflex monosynaptic or polysynaptic

monosynaptic.

Whether withdrawal reflexes are monosynaptic or polysynaptic:

polysynaptic

Whether crossed extensor reflexes are monosynaptic or polysynaptic:

polysynaptic

Ipsilateral reflex:

Movements occur on the same side of the body.

Contralateral reflex:

Movements occur on the opposite side of the body.

Plantar reflex (negative Babinski):

Normal response where the toes curl downward when the sole of the foot is stimulated.

Babinski sign (positive Babinski):

Abnormal response where the big toe dorsiflexes and the other toes fan out when the sole of the foot is stimulated, indicating upper motor neuron damage.