Neurons

Do NowDo NowHow does this relate to the

Nervous System?

Homework Due TodayRead Section 31.1Answer question 1-3 on page 900

HomeworkDescribe the function of the

nervous system?

The functions of the nervous sustem are to collect information about the body’s internal and external environments, process that information and respond to it

HomeworkDescribe how your peripheral

nervous system and central nervous system were involved in a simple activity you performed today.

HomeworkName and describe the three

types of neuronsSensory neurons carry impulses

from the sense organs. Motor neurons carry impulses from the brain and spinal cord to muscles and glands. Interneurons process the information from sensory neurons and send commands to other interneurons or motor neurons

HomeworkThe immune system of people

with multiple sclerosis attacks myelin sheaths in the CNS. The myelin breaks down and scar tissue may result. How do you think this would affect the transmission of signals from the CNS?

HomeworkWhat happens when a neuron in

stimulated by another neuron?

If the stimulus is grat enough, an impulse begins that travels rapidly along the axon toward the axon terminals, where the impulse may be passed on to other cells

HomeworkHow can the level of pain you

feel vary if a stimulus causes and all-or-none response?

Although the response is all-or-none, the frequency of action potentials can vary depending on the strength of the stimulus

Homework Due Next ClassFinish WorksheetDefine:

◦Peripheral Nervous System◦Central Nervous System◦Axon◦Myelin Sheath◦Threshold◦Synapse◦Neurotransmitter

The Nervous SystemThe Nervous System

The Nervous SystemThe Nervous System responds to

information collected from internal and external environments

Comprised of Peripheral Nervous System and Central Nervous System

Central Nervous SystemConsists of the brain and spinal

cord

Peripheral Nervous SystemAll nerves and supporting cells

that collect information about the body’s internal and external environment

PNS/CNSConstant communication is

happening between the 2 nervous systems

You’re walking around in the dark and can’t see anything. Your hands are reaching for the light switch and your PNS relays the message of what it is touching to the CNS, which relays back to the PNS as to what it is supposed to be looking for.

NeuronsAll impulses (messages) are

transmitted by cells called neurons◦Sensory◦Motor◦Interneurons

Process sensory information and send commands to other neurons

Structure of Neuron

Cell BodyLargest part of a neuronHouses the nucleus and most of

cytoplasm

Homework Due Next ClassFinish WorksheetDefine:

◦Peripheral Nervous System◦Central Nervous System◦Axon◦Myelin Sheath◦Threshold◦Synapse◦Neurotransmitter