The Nervous System

Unit 2: Biological Basis of Behavior

Lesson 2

Objectives:

Students will identify the parts and function of a neuron.

Students will explain how neurons communicate info from body to brain and vice versa.

Students will demonstrate reaction time and discrimination.

Students will diagram the nervous system.

Warm Up:

What are the three types of imaging techniques used to study the brain?

Building Blocks

Brain Cells

Neurons100 billionSend/receive chemo-

electrical signals (200 mph)

Glial (Glee-all) CellsTrillionsRegenerate

Types of Neurons

Sensory Neuron Afferent From senses to brain

Motor Neuron Efferent From brain to

muscles/organs.

Interneuron Association From one neuron to another.

Parts of the Neuron (Handout)

Cell body (soma) and nucleus.Dendrites

Axon and Myelin SheathEnd bulbs (Terminals)

Gray Matter: Darker CNS tissues made up of neurons’ cell bodies & dendrites

White Matter: Paler CNS tissues comprised of myelin-sheathed nerve fibers

Neuron CommunicationAll-or-none response, if nerve

impulse fires (reaches threshold) it will finish!

Neurotransmitter Chemical that transmits

impulse from neuron to neuron

Excitatory- cause next neuron to fire

Inhibitory- prevent next neuron from firing

Reuptake – if not accepted, reabsorbed into sending “buttons”

STOP! Review! Think…Don’t Write!

Neurons are brain cells that send and receive messages…

in form of electrical impulses and neurotransmitters that bridge synaptic gaps…

gaps are present to control/monitor activity by exciting or inhibiting next neuron…

Questions?

Reaction Time

Time it takes for a stimulus to reach the brain and the brain to send corresponding response back to the area of the stimulus

Reaction Time Demo - Rulers

Working in pairs, have one student place their arm across a desk with their hand projecting over the edge. Make sure to have the thumb and index finger separated by 1.5 inches. The other students should hold a ruler such that the lower edge of the ruler is even with the upper margin of the thumb and index finger. The second student should drop the ruler while the first student should try to catch the ruler by closing the thumb and finger. The first student should make sure not to move their hand…

Reaction Time Demo - Rulers

Think-Pair-Share

Why is it so difficult to catch the ruler? Explain in terms of the rate at which the nerve impulses travel along the nerves.

Effect of Discrimination on Reaction Time

DiscriminationDistinguishing between

stimuli…more stimuli, longer reaction time

Deck of cards exampleRows (shoulders)

example

Effect of Discrimination on Reaction Time

Deal a full deck into 1 pile as rapidly as possible. Time?

Deal a full deck of cards into 2 piles; one black, one red. Time?

Difference in time between above? This period of time measures the effect of the neural processes involved in discrimination.

Shuffle. Deal a full deck into 4 individual piles; hearts, spade, clubs, diamonds. Time? Why is there a difference from previous times?

Shuffle and repeat above. Time? Is there any evidence of training?

Neuroanatomy: Structure of the N.S.

Peripheral Nervous System

43 pair regenerable nerves connect sides/parts of body to CNS

Central Nervous System

Spinal Cord 43-45 cm Interneurons Transmit messages body-

brain

Brain 3lbs Neurons & Glial Cells

The Nervous System

Neurons (CNS) and Nerves (PNS) are the building blocks of the nervous system!

Peripheral Nervous System

Somatic N.S.

Controls voluntary movementsWalking, writing

Autonomic N.S.

Controls involuntary movements, lungs, digestion

Autonomic Nervous System

Sympathetic N.S.

“Fight or flight”

Prepares body to respond to stressful / emergency situations

Parasympathetic N.S.

“Rest & digest”

Returns body to normal functioning, energy conservation

Closure

How do the CNS and PNS work together to transmit neural messages?

Homework

PsychSim 4.0http://www.worthpublishers.com/kolb/content/psychsim/index.htm

Neural Messages HW