The Nervous System

Define the following terms:

• Nerve system• Receptor• Stimulus• Neuron

• Impluses• Effector• Brain• Synapse

In paragraph/diagram form, explain how all these terms are related to one another.

Draw a neuron and label the following parts:

• Cell body• Nucelus• Axon• Schwann Cell• Synaptic Knobs

To Do:

• Explain the difference between nerves, sensory neurons, motor neurons, and interneurons.

Protists

• Lack nervous system• Respond to stimuli in a co-

ordinated way• Not totally understood,

but are able to tell diff. b/n light/harmful chemicals, food/nonfood.

• Amoeba Feeds! http://www.youtube.com/watch?v=W6rnhiMxtKU

Hydra• Has a nerve net

• Nerve cells form irregular network b/n 2 layers of body wall

• Impulses cause muscles to respond– E.g. Tentacle touches food impulse

travels through organism animal stretches towards food tentacles capture food and stuff into mouth

• http://www.youtube.com/watch?v=Zgp7cutpO8o&feature=related

Earthworm• More complex nervous

system• Divided into the central and

peripheral system– Central: brain + ventral nerve

cords– Peripheral: nerves branching

to all parts of body• Has motor neurons (carry

impulses from nerve cords to muscles) and sensory neurons (impulses from receptors in skin to nerve cords)

Grasshopper

• Similar to the earthworm• Made of brain, ventral

nerve cord, ganglia (group of cells that co-ordinate impulses)

• Sense organs are better developed– Has eyes (antennae) or

feelers, taste organs, and are sensitive to sound

To Do:

• Summarize in your notes how the nervous system increases in complexity from the protists to the grasshopper. (Can draw a diagram if it is helpful to you)

Human Nervous System• Made up of the central

and peripheral system– Central: made of brain,

spinal cord, interneurons, and motorneurons. Controls most activities of the body

– Peripheral: network of nerves, conduct impulses b/n central nervous system & receptors/effectors of the body

To Do:

1) Draw a concept map of the brain explaining the 3 main parts and the functions they control

2) Outline the 2 main functions of the spinal cord. http://www.youtube.com/watch?v=udaCEBtqfb (~ 4 to 10 minutes)

3) Explain what a reflex is and the process that happens when you touch something hot and your hand withdraws.