A&P Nervous System Lecture Test Guide

the brain and spinal cord.

What are the main components which make up the central nervous system?

neuron.

The basic unit of the nervous system is called the ...

excitability.

The ability of the neuron to respond to a stimulus is ...

Afferent neurons

what type of neurons carry sensory signals from the body to the central nervous system.

efferent neurons

why type of neurons transmit motor signals from the central nervous system to the body.

properties of the neuron

excitability, conductivity, integration, and the ability to communicate through synapses are all.

neurotransmitters

dopamine, serotonin, norepinephrine, acetylcholine, and gamma-aminobutyric acid (GABA) are examples of

myelin sheath

insulate axons and increase the speed of nerve impulse conduction.

action potential

The wave of depolarization that spreads along the neuron is also called an...

neurotubules

involved in intracellular transport

involved in intracellular transport

Nissl bodies

involved in protein synthesis and are primarily composed of rough endoplasmic reticulum and ribosomes.

synaptic boutons

The bulging ends of the axon terminal are called...

dendrites

extensions of a neuron that receive signals from other neurons and transmit them toward the cell body.

axons

long projections of neurons that transmit electrical impulses away from the cell body to other neurons or muscles.

nodes of Ranvier

gaps in the myelin sheath that facilitate rapid conduction of nerve impulses through saltatory conduction.

IPSP decreases the likelihood of a neuron firing and EPSP increases the likelihood of a neuron firing.

What is the difference between IPSP and EPSP?

sympathetic and parasympathetic

What is the autonomic nervous system made up of?

oligodendrocytes

glial cells in the central nervous system that produce myelin, which insulates axons.

astrocytes

support and maintain the blood-brain barrier, provide nutrients to neurons, and regulate ion concentrations.

microglia

act as the immune cells of the central nervous system, removing debris and dead neurons.

Schwann cells

responsible for producing myelin in the peripheral nervous system and aiding in the repair of damaged nerves.

ependymal cells

line the ventricles of the brain and the central canal of the spinal cord, producing and circulating cerebrospinal fluid.

control, coordination, and integration

Major functions of the nervous system include

Central Nervous System (CNS)

the control center for the entire nervous system is

the brain

primary center for regulating and

coordinating body activities. (THE COMPUTER)

spinal cord

center of reflex action containing the

conducting paths to and from the brain.

brain and spinal cord

the Central Nervous System is made up of the

Peripheral Nervous System (PNS)

convey impulses to and

from the brain (cranial nerves) or spinal cord (spinal

nerves).

afferent and efferent divisions

The peripheral nervous system is made up of:

Afferent (sensory) division

sensory neurons conduct information toward the C.N.S.

Efferent (motor) division

motor neurons conduct information away from the C.N.S.

somatic and autonomic nervous systems

the efferent (motor) division consists of

Somatic Nervous System (SNS)

consists of efferent neurons that conduct impulses from the C.N.S. to skeletal muscles, and is under conscious control.

Autonomic Nervous System (ANS)

consists of efferent neurons that conduct impulses from the C.N.S. to smooth muscle, cardiac muscle, and glands. Usually not under conscious control.

sympathetic and parasympathetic

the autonomic nervous system is subdivided into

Sympathetic Nervous System

the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations

Parasympathetic Nervous System

the division of the autonomic nervous system that calms the body, conserving its energy

Neuroglial Cells

support and protect the nervous system. includes astrocytes, oligodendrocytes, ependymal cells, and microglia

Astrocytes

most numerous, star shaped bodies, that play a major role in the transfer of materials to and from circulation (so-called blood brain barrier). Attaches neurons to their blood vessels.

Oligodendrocytes

functions in myelination of the C.N.S.

Ependymal Cells

cellular layer of epithelial cells that line the ventricles of the C.N.S., modified to produce cerebrospinal fluid; therefore, are also cells of choroid plexus.

Microglia

small phagocytic cells derived from connective tissue. They play a role in the destruction of dead tissue and defense against microorganisms.

Neurons

structural and functional units of the nervous system. they conduct action potentials. 3 major structures include the cell body, dendrites, and axon

cell body

central portion containing the nucleus, nucleolus, and other

organelles.

Nissl Bodies

condensations of rough endoplasmic reticulum (RER) which form dark staining bodies. They contain RNA and protein, and functions in protein synthesis.

Neurofibrils

slender rod-like structures composed of microtubules and fibrils; they play a role in cell support and release of neurotransmitters.

Dendrites

highly branched, short cell processes which conduct action potentials toward the cell body, (they contain Nissl bodies).

Axon

one long cell process which conducts action potentials away from the cell body (they do not contain Nissl bodies).

Myelin Sheath

white, fatty covering of axons produced by Schwann Cells in the P.N.S.; insulates and protects the axons.

Schwann Cells

produce myelin in the P.N.S.

Oligodendrocytes (neuroglia)

produce myelin in the C.N.S

Nodes of Ranvier

unmyelinated segments of an axon where nerve impulses are produced.

Neurolemma

outermost membrane, the cell membrane of a neuron's Schwann cell. It covers the myelin sheath.

Synapse

where end fibers of the axon of one cell body meet the end fibers of the dendrite of another. Junction between two neurons.

Motor, Sensory, and Interneurons

Functional (Physiological) Classification -

according to the direction in which the impulse is traveling.

Multipolar, Bipolar, and Unipolar

Structural (Anatomical) Classification -

according to the number of processes extending from the cell body.

Motor (Efferent) Neurons

transmit impulses from the C.N.S. to the effected site.

Sensory (Afferent) Neurons

transmit impulses from the effected site to the C.N.S.

Interneurons (Associate Neurons)

found in the C.N.S. and connect sensory neurons to motor neurons.

Multipolar Neurons

most common type have several dendrites and one axon extending from the cell body (ex. - motor neurons).

Bipolar Neurons

have two processes, one dendrite and one axon extending from the cell body; relay information concerning special senses.

Unipolar Neurons

dendrite and axonal process are continuous and both come off the cell body. Sensory neurons are usually amoung these

Exteroceptors

Located near surface, provide information about the external environment such as touch, temperature, hearing, vision, smell, etc.

Interoceptors

Provide information about the internal environment, located in the digestive, respiratory, cardiovascular, urinary, and reproductive systems; detect deep pressure and pain.

Proprioceptors

Provide information about the position and movement of skeletal muscles and joints.

Nerve Impulse

Depends on polarization and depolarization of the neuronal membrane.

Membrane Potentials

Indicated by the difference between the amount of ion concentration outside the plasma membrane.

Polarization

Potassium (K+) ions are highly concentrated inside the cell, and sodium (Na+) ions are highly concentrated outside the cell.

Depolarization

Allows for transport of Na+ across the cell membrane and into the cell, and K+ outside of the cell; mechanism is called the 'sodium-potassium pump.'

Repolarization

Return of ions to the polarized state.

Action Potential

Initiated after depolarization has taken place; it is the principal way in which neurons communicate.

Refractory Period

When a nerve receives a second stimulus at such a close interval that no response will occur; the nerve must have sufficient time to recover from the initial stimulus.

All or None Response

If a stimulus is strong enough to initiate an action potential, the impulse will travel along a neuron until its transmission is complete.

White Matter

Group of myelinated nerve fibers and associated neuroglia.

Gray Matter

Contains cell bodies and unmyelinated nerve fibers.

Nerve

A group of nerve cells (neurons) located outside the C.N.S.

Tracts

A group of nerve cells (neurons) located inside the C.N.S.

Ascending Tracts

Conduct sensory impulses up the spinal cord to the brain.

Descending Tracts

Conduct motor impulses down the spinal cord.

Ganglion

A collection of neuron cell bodies located in the P.N.S. (that is, outside the C.N.S.).

Nucleus

A collection of neuron cell bodies located inside the C.N.S.

Horns

Areas of grey matter located in the spinal cord.

Posterior (Dorsal) Gray Horns

Contains sensory nuclei.

Anterior (Ventral) Gray Horns

Contains motor nuclei.

Spinal Cord

An ovoid column of nervous tissue about 18 inches long, extending from the medulla oblongata to the 2nd lumbar vertebrae.

Cervical Enlargement

Nerves arising from this region are associated with the upper extremities.

Lumbar Enlargement

Nerves arising from this region are associated with the lower extremities.

Cauda Equina

After the terminal portion of the spinal cord; composed of the roots of spinal nerves below the first lumbar vertebrae.

Denticulate Ligaments

Extensions of the pia mater to dura mater; prevent lateral movement of the cord.

Protection of the CNS

Purpose of the bony cranium & vertebral column, meninges, and cerebrospinal fluid.

Meninges

Membranes surrounding the CNS and function in protection.

Dura Mater

A tough outer layer which is fused to the periosteum of the cranial bones and vertebrae; ends at S2.

Epidural Space

Between skull and vertebrae and the dura mater; contains a protective padding of adipose tissue.

Subdural Space

Narrow space that separates the dura mater from the arachnoid meninge.

Arachnoid

The second or middle membrane; very delicate and sends webs down to the pia mater; ends at S2.

Subarachnoid Space

Separates the arachnoid layer from the inner meninge; filled with CSF.

Pia Mater

The innermost meningeal membrane; very thin and delicate, tightly attached to the surface of the brain and spinal cord; ends at L1 ½.

Meningitis

Inflammation of the meninges, generally due to bacteria or virus.

Reflex Arc

A neural pathway between the point of stimulation (receptor) to the brain or spinal cord and to the responding organ (effector).

Components of a Reflex Arc

Receptor, sensory neuron, interneuron, motor neuron, effector.