A&P Test 3- Nervous System

Cranial Nerves

12 pairs. Active in four categories: special sensory impulses, general sensory impulses, somatic motor impulses and visceral motor impulses

Meninges

3 layers of connective tissue surrounding the brain and spinal cord.

Sensory Neuron

A cell that transmits impulses toward the CNS

Cerebrospinal Fluid

A clear liquid that circulates in and around the brain and spinal cord. Formed by four spaces in the brain known as ventricles.

Myelin

A fatty material that covers axons. It functions to insulate and protect the fiber.

Nerve

A fiber bundle located within the PNS

Spinal Cord

A link between the peripheral nervous system and the brain. It helps to coordinate impulses within the CNS. It is protected by the vertebrae. Each vertebrae fits together to form a continuous tube extending from the occipital bone to the coccyx.

Effector

A muscle or a gland outside the CNS that carries out a response

Posterior Median Sulcus

A narrow grove that divides the right and the left portions of the posterior white matter

Tract

A similar grouping to a nerve, but located within the CNS

Cerebral aqueduct

A small canal that extends from the midbrain to the fourth ventricle

Central Canal

A small channel found in the center of the gray matter that contains cerebrospinal fluid. Cerebrospinal fluid is the liquid that circulates around the brain and the spinal cord.

Sensory Nerves

Afferent. These cranial nerves contain only sensory fibers containing impulses toward the brain. A few of the cranial nerves contain only sensory fibers.

Interneurons

Also called central association neurons. They relay information from place to place within the CNS. In addition to immediate withdrawal from pain, impulses may travel to other parts of the CNS to help retain balances as you withdraw your hand or to help you learn how to avoid putting your hand on hot stoves.

Frontal Lobe

Anterior to the central sulcus. Contains primary motor area- provides conscious control of skeletal muscles. Contains areas that are important in speech.

Decrease

As an individual ages, the brain begins to __________ in size and weight.

Nicotine Receptors

Bind nicotine. These receptors are found on skeletal muscle cells and stimulate muscle contraction when ACh is present.

Adrenergic Receptors

Bind norepinephrine and epinephrine (which can either stimulate or inhibit organs.) Found on effector cells of the sympathetic nervous system. Divided into alpha and beta.

Cholinergic Receptors

Binds acetylcholine, and divided into two types

Muscarinic Receptors

Binds muscarine (a poison). These receptors are found on effector cells of the parasympathetic nervous system.

II- Optic Nerve

Carries visual impulses (sight)

Motor Neurons

Carry impulse from the CNS out to the muscle and glands. The CNS responds to the pain of touching the hot stove and directs your skeletal muscles in your arm to flex and withdraw your hand or to help you learn how to avoid putting your hand on hot stoves. Also known as "efferent neurons." Like cause and effect, what you do in response.

Neuroglia

Cells that support and protect the neurons

Sensory Neurons

Conduct impulses to the spinal cord and brain. Touching a hot stove with your hand, sensory neurons carry impulses generated by that stimulus (hot stove) to the CNS for interpretation. Also known as "afferent neurons." If something affects you, it happens to you.

Brain Stem

Connects the cerebrum and diencephalon with the spinal cord. The superior portion is called the midbrain. Inferior to the midbrain is the pons, followed by the medulla oblongata on the floor of the skull.

Medulla Oblongata

Contains centers called nuclei which house vital centers such as: respiratory center, cardiac center, vasomotor center.

III- Oculomotor Nerve

Contraction of eye muscles (eye movement)

Autonomic Nervous System

Controlled involuntarily (automatically or unconsciously) controls the smooth muscle, cardiac muscle, and glands

Somatic Nervous System

Controlled voluntarily (by conscious will) and affects the skeletal muscles

XII- Hypoglossal Nerve

Controls tongue muscles (tongue movement)

Cerebral Hemispheres

Divided into the left and right hemispheres

Motor Nerves

Efferent. These cranial nerves contain only motor fibers conducting impulses away from the brain. A few of the cranial nerves contain only motor fibers.

EEG

Electrical signals that occur as the brain functions are picked up by electrodes placed on the head

Horns

Extensions of the ventricles that extend into the lobes

VI- Abducens Nerve

Eye ball muscles (eye movement)

VII- Facial Nerve

Facial expression occurs here

Choroid Plexus

Forms CSF by filtration of blood and cellular secretions

Midbrain

Forms the superior part of the brain stem

Neurons

Functional cells of the nervous system that are highly specialized and have a unique structure related to their function

V- Trigeminal Nerve

General sense impulses from eye, upper jaw, and lower jaw (chewing)

VIII- Vestibulocochlear Nerve

Hearing and equilibrium from inner ear

One of the first systems

How early does the nervous system develop in the embryo?

Cerebellum

Immediately below the posterior part of the cerebral hemispheres. Connected with the cerebrum, brain stem and spinal cord by means of the pons.

Schwann Cells

In the PNS, this wrap around the axon like a jelly roll depositing layers of myelin.

Increased

Incidence on stroke is _______________ due to vascular degeneration.

Peripheral Nervous System

Includes all the cranial nerves that carry impulses to and from the brain, and all the spinal nerves that carry messages to and from the spinal cord.

Central Nervous System

Includes the brain and the spinal cord

Temporal Lobe

Inferior to the lateral sulcus. Contains the auditory areas- receives and interprets impulses from the ear. Olfactory area, which involves the sense of smell, is located here.

Pia Mater

Innermost layer around the brain. Attached to the nervous tissue of brain and spinal cord.

CT Scan

Lesions such as tumors or scar tissue are easily identifiable with this test. Provides photographs of bones, soft tissue, and cavities of the brain.

Pons

Lies between the midbrain and the medulla and is responsible for respiratory reflexes and communication between the cerebellum and nervous system

Schwann cells that form the myelin sheath in the PNS. Oligodendrocytes. Astrocytes.

List 3 types of neuroglia

Protect and nourish nervous tissue. Support nervous tissue and bind it to other structures. Aid in repair of cells. Act as phagocytes to remove pathogens and impurities. Regulate the composition of fluids around cells.

List 4 functions of neuroglia

Sympathetic Nervous System and Parasympathetic Nervous System

List the 2 divisions of Autonomic Nervous System

Dura Mater, Arachnoid, and Pia Mater.

List the 3 layers of the meninges

Resting state. Depolarization. Repolarization

List the 3 states of action potential

Receptor, Sensory Neuron, Central Nervous System, Motor Neuron, Effector

List the 5 fundamental parts of a reflex arc include

Epinephrine. Norepinephrine. Acetylcholine. Serotonin. Dopamine.

List the 5 neurotransmitters that pass through the synaptic cleft

Cerebrum, diencephalon, brain stem, cerebellum, meninges.

List the 5 sections of the brain.

Increase in rate and force of heart contractions, blood pressure, and basal metabolic rate. Dilation of blood vessels to skeletal muscle, bronchial tubes, the pupil, and decrease in focusing ability. Stimulation of the central portion of the adrenal gland.

List the functions of the Autonomic Nervous System

Cholinergic and Adrenergic receptors

List the two important classes of receptors

Hypothalamus

Maintains homeostasis by controlling body temperature, water balance, sleep, appetite and emotions. Controls both sympathetic and parasympathetic systems

Arachnoid

Middle layer of the meninges. Loosely attached to the deepest of the meninges, which allows Cerebrospinal Fluid to move freely

Mixed Nerves

Most of the cranial nerves and all of the spinal nerves contain both sensory and motor fibers. Note that in this nerve, impulses may be traveling in two directions (toward and away from the CNS), but each individual fiber in the nerve is carrying impulses in one direction only.

Descending tract

Motor impulses travel from brain toward the peripheral nervous system via this tract

Parasympathetic Nervous System

Motor neurons for this system begin in the craniosacral areas. Releases the neurotransmitter acetylcholine. This system may be referred to as cholinergic meaning "activated by acetylcholine." Acts as a balance for the sympathetic system once a crisis has passed.

Sympathetic Nervous System

Motor neurons for this system originate in the spinal cord with cell bodies in the thoracic and lumbar regions. Produces a response that prepares individuals for emergency, extreme stress, or danger (fight or flight response). Releases the neurotransmitters epinephrine and norepinephrine. These systems may be referred to as adrenergic meaning "activated by adrenaline"

Frontal, Parietal, Temporal, and Occipital

Name the four lobes of the Cerebral Hemispheres

Somatic Nervous System and Autonomic Nervous System

Name the two functional divisions of the Nervous System

Central Nervous System and Peripheral Nervous System

Name the two structural divisions of the Nervous System

Axons

Neuron fibers that conduct impulses away from the cell body. Single fibers which can be long. These impulses may be delivered to another neuron, to a muscle, or to a gland.

Dendrites

Neuron fibers that conduct impulses to the cell body. They have a tree like appearance. They function as receptors in the nervous system. They receive a stimulus that begins neural pathway

IV- Trochlear Nerve

One eye ball muscles (eye movement)

Parietal Lobe

Posterior to the central sulcus. Contains primary sensory area- interprets impulses from the skin such as pain, tough and temperature

Occipital Lobe

Posterior to the parietal lobe and extends over cerebrum. Contains the visual receiving area and visual association area, which interpret impulses from the retina.

1- Olfactory Nerve

Responsible for smell

Short term memory

Retention of information for a few seconds or minutes

Long term memory

Retention of information that can be recalled at a later time

Brachial Plexus

Sends branches to the shoulder, arm, forearm, wrist and hand. (Radial nerve starts here)

Ascending tract

Sensory impulses entering the spinal cord are sent to the brain via this tract

Unmyelinated tissue

Small, irregularly shaped internal section of gray matter surrounded by a larger area of white matter known as myelinated axons. The internal gray matter is arranged so that there are columns of gray matter that extend up and down dorsally.

Thalamus

Sorts out impulses and directs them to different areas of the cerebral cortex. Responsible for the interpretation of sensation, including pain, temperature, and touch

A. Decreases B. Slowed

Speed of processing information ______________ and movements are _____________.

Cervical Plexus

Supplies motor impulses to the neck muscles and receives impulses from the neck and back of the head (this is where the Phrenic nerve starts.)

Lumbosacral Plexus

Supplies nerves to the pelvis and legs. Sciatic nerve, which is the largest branch in this plexus, starts here.

IX- Glossopharyngeal Nerve

Taste, salivary glands, swallowing

Diencephalon

The area between the cerebral hemispheres and the brain stem. The thalamus and hypothalamus are included here.

Gray Commisure

The bridge of the gray matter that connects the right and left horns.

Receptor

The end of a dendrite or some specialized receptor cell, that detects a stimulus

Cerebrum

The largest part of the brain. Divided into right and left cerebral hemispheres. This division is caused by a deep grove known as Longitudinal fissure.

Acetylcholine

The neurotransmitter released at the neuromuscular junction, the synapse between a neuron and a muscle cell

Dura Mater

The outermost membrane. Thickest and toughest layer of meninges. Surrounds the brain in two layers. Outer layer is fused to the cranial bones.

Reflex Arc

The pathway through the nervous system from stimulus to response

Synapse

The point junction for transmitting the nerve impulses

Depolarization

The second state of action potential. A stimulus of adequate force, such as electrical, chemical or mechanical energy. Sodium ions are allowed to flow into the cell.

Synaptic Cleft

The tiny gap between the cells where information is must be passed from one cell to another at the synapse. Information that crosses this gap, does so in the form of a neurotransmitter.

Spinal Nerves

There are 31 pairs of these. They are numbered according to the level of the spinal cord from which it arises.

Plexuses

These are the larger, anterior branches of spinal nerves that form networks. They then distribute branches into other body parts.

Dorsal and Ventral Horns

These two pair of columns give gray matter an H-shaped appearance in cross section.

Anterior Median Fissure

This grove separates the right and left portions of the anterior white matter.

Repolarization

This occurs as the electrical charge returns to its resting value. Potassium channels open to allow potassium to leave the cell.

XI- Accessory Nerve

Two branches, one controlling trapezius and sternocleidomastoid and one controlling muscles of larynx (upper body movement)

Phagocytes

Type of cell within the body capable of engulfing and absorbing bacteria

PET

Visualizes the brain in action

X- Vagus Nerve

Voice box. Supplies most of thoracic and abdominal cavities.

It diminishes

What happens to memory as you get older?

To relay information to and from the CNS or to different places within the CNS itself.

What is the job of the neurons in the CNS?

The narrowing of arteries

Why is blood flow reduced as you age?

MRI

can evaluate for tumors, scar tissue and hemorrhaging that cannot be shown by a CT

Node of Ranvier

the gap at regular intervals between segments of myelin sheath along the axon. These speed up the process for transmitting signals from CNS to muscle.

Neruilemma

thin coating formed by the Schwann cells. Acts as part of the mechanism that some peripheral nerves repair themselves when injured.