The Nervous System (Ch 11)

myelin sheath

covers the axon of some neurons and helps speed neural impulses

Multiple Sclerosis (MS)

destruction of the myelin sheath on neurons in the CNS and its replacement by plaques of sclerotic (hard) tissue

peripheral nervous system

nerves outside the CNS

Scwann cells

neuroglia that make up the myelin sheath in the PNS

Cells that provide direct protection and physical support to neurons are

neuroglial cells

Forebrain

receives, integrates sensory input, determines complex behavior

functions of myelin sheath

speeds up transmission of action potentials, involved in the repair of damaged neurons in the peripheral nervous system, insulates a neuron and saves the neuron energy

Amyotrophic lateral sclerosis (ALS) is a demyelinating disease that results from nerve damage beginning in the

spinal cord

The central nervous system is composed of

the brain and spinal cord

Saltatory conduction is

the process of conduction leaping along myelinated neurons

What are the main characteristics of the nervous system?

- Receives information from many sources simultaneously -Integrates information (processes, compiles, makes sense of this information) -Extremely fast—can receive, integrate, and respond in tenths of a second -Can initiate specific responses such as muscle contraction, glandular secretion, conscious control over movement

sequence of action potential

1. the membrane is depolarized 2. potassium channels within the membrane are open 3. the membrane has repolarized 4. voltage threshold for membrane

During synaptic transmission, the influx of ________ causes vesicles in the axon bulb to fuse with the cell membrane, releasing ________

Ca2+, neurotransmitter

Functions of the Peripheral Nervous System

Deliver sensory information to the CNS Carry motor commands to peripheral tissues and systems

Oligdendrocytes

Forms myelin sheaths of axons in the CNS

transmit electrical impulses within the central nervous system

Interneurons

Which component of the nervous system is divided into the somatic and autonomic divisions?

Motor Division

Transmit impulses away from the central nervous system

Motor neurons

Oligodendrocytes are similar to Schwann cells in that they

are a type of neuroglial cell

Glial Cells do not

transmit action potential

Functions of the Central Nervous System

Receives, Processes and transfers info

What provides the central nervous system with information about the outside environment?

Sensory Division

transmit impulses towards the central nervous system

Sensory Neurons

Synapse

Special junction between axon terminus and target cells

Action potential

an electric signal that is conducted along a neuron's axon to a synapse

Axons branch into axon terminals, which have ________ located at the terminal ends

bulbs

White Matter

consists of myelinated nerve tracts (sensory and motor)

Gray Matter

contains cell bodies (dendrites)

Hindbrain

coordinates basic, automatic, and vital tasks

Midbrain

coordinates hearing and visual reflexes