Nervous System (finals) Flashcards by Zahra Swagger

The two types of cell populations that make up the nervous tissue.

Neuroglial Cells and Neurons

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What is the major functional difference between neuroglial cells and neurons?

Neuroglial cells function as support and protection to neurons. Neurons function to transmit messages from one part of the body to another in form of nerve impulses.

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What sub-type of Neuroglial would you find in the lining the central canal?

Ependymal

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What is the function of ependymal?

Transportation of electrolytes.

Important role on the production and regulation of cerebrospinal fluid.

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What is the structure and function of dendrites?

Structure: Tree shaped/branching
Function: Bear receptors for neurotransmitters

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What is the structure and function of axons?

Structure: Long tail-like
Function: Allow neurons to transmit electrical and chemical signals to other cells.

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What is the structure and function of nissl bodies?

Structure: Granular
Function: Synthesis and segregation of proteins

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What is the structure and function of synapse?

Structure: Gap between neurons
Function: Allows a signal to pass from one neuron to another

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What is myelin made of?

Fatty substance

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What are three functions of the myelin sheath?

Protects and electrically insulates fibers
Increases transmission speed of nerve impulses
Conduct rapid nerve impulses

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What is the structure of neurilemma?

Outermost nucleated cytoplasmic layer of Schwann cells.

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What is the function of the neurilemma?

Protects the peripheral nerve fibers

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What is the structure of the nodes of ranvier and what would you find in the nodes?

The gaps/indentations in the myelin sheath. You would find axon collaterals.

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What is the function of the nodes of ranvier?

Allow the generation of a fast electrical impulse along the axon

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What determines if a neuron is unipolar, bipolar, or multipolar?

Based on the number of processes extending from their cell body

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Structure and function of a unipolar neuron

Structure: Single short process that divides T-like into proximal and distal branches.
Function: Associated with a sensory receptor and function as sensory neurons.

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What is the structure and function of a bipolar neuron?

Structure: Two-processes; an axon and dendrite that extend from opposite sides.
Function: Essentially sensory neurons.

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What is the structure and function of a multipolar neuron?

Structure: Many processes that extend from the cell body. All are dendrites except for a single axon.
Function: Mostly interneurons that conduct impulses within CNS, integrating sensory input and motor output.

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The neurons in the DRG are ________ neurons (structurally) and _________ neurons (functionally)

Pseudo-unipolar

Afferent

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Function and state (uni/bi/multipolar) of sensory or afferent neuron

Function: Carry impulses from sensory receptors in the internal organs
Typically unipolar

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Function and state (uni/bi/multipolar) of a motor or efferent neuron

Function: Carry impulses from the CNS to the internal organs and/or body muscles and glands.
Typically multipolar.

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Function and state (uni/bi/multipolar) of association or interneurons

Function: Contribute to pathways that connect sensory and motor neurons.
Typically multipolar

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How does a neuron differ from a nerve/tract?

Bundles of axons in the CNS are tracts.

Bundles of axons in the PNS are nerves.

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What nerve conducts impulses toward the CNS?

Afferent/sensory nerve

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What nerve carries impulses away from the CNS?

Efferent/motor nerve

What is a mixed nerve?

Carry both sensory/Afferent and motor/efferent fibers/impulses.

What is the endoneurium?

Delicate CT sheath surrounding each axon, within a nerve.

What is perineurium?

Coarse CT that binds groups of axons

What are fascicles?

Bundles of fibers formed by perineurium

What is epineurium?

White, fibrous CT sheath that binds together all the fascicles

What is the function of the CT associated with a nerve?

Helps fibers travel within a nerve

What are the two functions of the spinal cord?

1) Communication center | 2) Spinal reflex activity

What is the conus medullaris?

Tapering lower part of the spinal cord. | Cone shaped.

What is the cause equina?

Collection of nerve roots at the lower end of the spinal cord.

What is the filum terminale?

Fibrous extension of the conus medullaris

At what vertebral level does the spinal cord stop?

Lumbar vertebrae/level

Name the glial cell type that lines the central canal

Ependymocytes

What would you find in the central canal of a living mammal?

Cerebral spinal fluid

A network of nerves or vessels in the body

Plexus

Spinal level of the cervical plexus

C1-C5

Provides the primary motor supply to the diaphragm

Phrenic nerve

Spinal level of the brachial plexus

C5-C8 and T1

Supplies all the extensor muscles of the arm,forearm, hand, and the skin. Passes down the post-lateral surface of the arm and forearm.

Radial nerve

Supplies most of the flexor muscles in the forearm and several muscles in the hand. Passes down the anteromedial surface of the forearm.

Medial nerve

Supplies the arm muscles the flex the forearm and the skin of the lateral surface of the forearm.

Musculocutaneous nerve

Supplies the flexor carpi ulnaris, the ulnar head of the flexor digitorum profundus of the forearm, and all intrinsic muscles of the hand not served by the medial nerve. Travels down the posteromedial surface of the arm.

Ulnar nerve

Spinal level of the sacral plexus

L1-L4

Passes beneath the inguinal ligament to innervate the anterior thigh muscles. The cutaneous branches supply the skin of the anteromedial surface of the entire lower limb.

Femoral nerve

Spinal level of the sacral plexus

L4-S4

Largest nerve in the body. Leaves the pelvis through the greater sciatic notch and travels down the posterior thigh, serving its flexor muscles and skin.

Sciatic nerve

Cutaneous branch to skin of anterior and lateral surface of leg and sprain of foot. Motor branches to short head of biceps femoris of thigh, fibularis muscles of lateral leg, tibialis anterior, and extensor muscles of toes.

Common fibular nerve

Cutaneous branch to skin of posterior surface of leg and sole of foot. Motor branches to muscles or back of thigh, leg, and foot.

Tibial nerve

Define reflex

Rapid, unpredictable, involuntary motor response to stimuli

Five essential components of all reflex arcs

1. Receptor 2. Sensory neuron 3. Integration center 4. Motor neuron 5. Effector

Difference in autonomic reflexes and somatic reflexes

Autonomic reflexes activate smooth or cardiac muscle and/or glands. Somatic reflexes activate skeletal muscle.

Five somatic reflexes

1. Stretch 2. Crossed-Extensor 3. Superficial 4. Corneal 5. Gag

Is the stretch reflex a spinal or cranial nerve reflex?

Spinal

Is the crossed-extensor reflex a spinal or cranial reflex?

Spinal

Is the superficial reflex a spinal or cranial reflex?

Spinal

Is the corneal reflex a cranial or spinal reflex?

Cranial

Is the gag reflex a spinal or cranial reflex?

Cranial

What muscle contracts in the patellar/knee-jerk reflex?

Quadriceps

What nerves is carrying the Afferent and efferent impulses in the patellar/knee-jerk reflex?

Femoral nerve

What is the result of Achilles/ankle-jerk reflex?

The foot drops down *calf muscle (gastrocnemius) contracts

What are the results of the crossed extensor reflex?

The other side of the body from the stimulus compensates

Why is the crossed extensor reflex slower than other reflexes?

Longer pathway causing a synapse

What are the two reflexes in which the reflex pathway is initiated and completed at the spinal cord level?

1. Stretch reflex | 2. Crossed-extensor

What two stimuli initiate the superficial cord reflex?

Pain and temperature

What is the response when superficial cord reflex is tested?

The toes curl and move downward

What two parts of the nervous system does the superficial cord reflex depend?

Upper motor pathways and cord level reflex arc

What two cranial nerves control the gag reflex?

Glossopharyngeal (IX) and Vagus (X) nerves

What is the pupillary response to light being shinned into the eye?

It constricts

What is consensual response?

When one eye constricts from light so does the other.

When a consensual response occurs, what does this indicate about the pathways involved?

They are connected

Function of papillary responses

Control the amount of light that enters the eye thus protecting the retina from becoming damaged

Effector of salivary reflex?

Salivary glands

Of the somatic reflexes, stretch reflexes are

Achilles reflex and patellar reflex

Of the somatic reflexes, the superficial cord reflex is

Plantar reflex

Of the somatic reflexes, the reflex mediated by cranial nerves is

Gag reflex

Reflexes classified as autonomic reflexes are:

1. Ciliospinal reflex 2. Pupillary light reflex 3. Salivary reflex

Sensory receptor in the viscera that is sensitive to changes and stimuli within the body’s internal environment

Interoceptor

Sensory receptor at or near the surface of the skin that responds to stimuli from the external world

Exteroceptor

Define stimulus

An excitant; a change in the environment that evokes a response

What was test in the two-point discrimination test?

Touch sensitivity

What two body areas are the most sensitive to touch?

Fingertips and palm of the hand

What two body areas are the least sensitive to touch

Back of the neck and the central forearm

Which appears to be more numerous - receptors that respond to cold or heat?

Cold

Why is it advantageous to have pain receptors that are sensitive to all vigorous stimuli, whether heat, cold, or pressure?

To prevent injury

Why is non-adaptability of pain receptors important?

Keeps us alert, preventing injury

Pain felt at a site other than the area of origin

Referred pain

Lateral rectus

Moves eye laterally

Medial rectus

Moves eye laterally

Superior rectus

Elevates eye and turns it medially

Inferior oblique

Elevates eye and turns it laterally

Inferior rectus

Depresses eye and turns it medially

Superior oblique

Depresses eye and turns it laterally

What muscles are responsible when you look left? Right eye and left eye

R: medial rectus L: lateral rectus

What muscles are responsible when you look up and to the left? Right and left eye

R: superior rectus L: inferior oblique

What muscles are responsible when you look down? Right and left eye

Both: inferior rectus

Function of the cornea

Major light bending medium of the eye

Function of sclera

Helps maintain shape of the eyeball and provides an attachment point for the extrinsic eye muscles

Function of the optic nerve

Transmits sensory information in form of electrical impulses

Function of the pupil

Allows light to enter the eye

Function of the ciliary body

Contains the ciliary muscle and ciliary process

Function of the radial muscle

Relax and contact to maintain a fairly constant level of light entering the eye

Function of circular muscle

Constricts the pupil

Function of suspensory ligaments

Attaches the lens to the ciliary process

Function of lens

Focuses light rays onto the retina

The ability of the eye to focus differentially to close objects

Accommodation

Function of choroid plexus

Barrier at the interface between the blood and cerebrospinal fluid

Function of arachnoid villi

One way valve for the flow of CSF into venous blood

Function of the optic nerve

Transmit sensory information for vision in the form of electrical impulses from the eye to the brain

Function of olfactory nerve

Conveys the sense of smell

Function of the oculomotor nerve

Allows movement of the eye muscles, constriction of the pupil

Function of trigeminal nerve

Sends pain, touch, and temperature sensations from your face to your brain

Function of abducens nerve

Controls movement of one of the eye muscles, lateral rectus

Function of the cerebrum

Initiates and coordinates movement and regulates temperature

Function of the cerebellum

Coordination and movement related to motor skills

Function of the medulla oblongata

Transmitting signals between the spinal cord and the higher parts of the brain

Function of the hypothalamus

Controls your hormones

What are the two major functions of the choroid?

1) Nourish the outer layers of the eye | 2) Absorb excess light

Function of tapetum lucidum

Reflects light back, makes it easier for animals to see at night

Function of the vitreous humor

Holds retina in place

What two specific photo-receptors make up the nervous layer of the retina?

Rods and cones

Rapid involuntary movement of the eye

Nystagmus

Sensation of whirling and loss of balance, associated particularly with looking down from a great height, or causes by disease affecting the inner ear or the vestibular nerve

Vertigo

Three papillae found on the dorsal tongue surface

1. Vallate papilla 2. Foliate papillae 3. Fungiform papillae

Which papillae don’t have taste buds? What do they have?

Filiform, sensory receptors

Taste and smell receptor are both classified as __________, because they both respond to __________

Chemoreceptors | Chemicals in solution

Nervous System (finals) Flashcards

(129 cards)