The Nervous System

Vocabulary!

1. Neuron2. Dendrites3. Axon4. Synapses5. Central Nervous

System

6. Peripheral Nervous System

7. Cerebrum8. Reflex

The Nervous System• The Nervous System is a complex network of cells that communicate and

control mental and physical activity within the human body.• A NEURON is a nerve cell.• Extending from a nerve cell body are membrane covered extentions

called DENDRITES. • DENDRITES receive info from other cells and carry info to the cell body.• Another extension, the AXON, transmits information away from the cell.• The MYELIN SHEATH insulates the axon and protects it.• SYNAPSES are juntions between neurons and other cells.

Draw and Label in Your Notes

Structure of the Nervous System

• CENTRAL NERVOUS SYSTEM= the brain and spinal cord

• The brain is the control center• The spinal cord carries nerve signals between the

body and the brain• PERIPHERAL NERVOUS SYSTEM= the neurons that

have cell bodies that are not part of the brain or spinal cord

The Brain

•CEREBRUM- largest portion of the human brain, folded outer layer

•2 cerebral hemispheres, 4 lobes (frontal, parietal, occipital, temporal)

Insert Brain Diagram with labels

• Handout

Brain Pop! Brain

Brain Coloring!

PERIPHERAL NERVOUS SYSTEM• NERVES are the bundled axons and dendrites found outside the

central nervous system• The SENSORY DIVISION of the peripheral nervous system contains

sensory receptors and interneurons that connect the outer body to the central nervous system.

• The MOTOR DIVISION lets the body react to sensory information• The SOMATIC NERVOUS SYSTEM is a body’s voluntary motor

response (moving your body)• REFLEXES are involuntary and often self-protective movements• AUTOMATIC NERVOUS SYSTEM controls internal body conditions

(respiration, heart rate, digestion, etc)

Reflex Activity• Get a meter stick. Hold the ruler near the end (highest

number) and let it hang down. Have another person put his or her hand at the bottom of the ruler and have them ready to grab the ruler (however, they should not be touching the ruler). Tell the other person that you will drop the ruler sometime within the next 5 seconds and that they are supposed to catch the ruler as fast as they can after it is dropped. Record the level (inches or centimeters) at which they catch the ruler.

• Test the same person 3 (vary the time of dropping the ruler within the 5 second "drop-zone" so the other person cannot guess when you will drop the ruler).

• Here is a table to convert the distance on the ruler to reaction time. For example, if you caught the ruler at the 8 inch mark, then your reaction time is equal to 0.20 seconds (200 ms). Remember that there are 1,000 milliseconds (ms) in 1 second.

Distance Time

2 in (~5 cm) 0.10 sec (100 ms)

4 in (~10 cm) 0.14 sec (140 ms)

6 in (~15 cm) 0.17 sec (170 ms)

8 in (~20 cm) 0.20 sec (200 ms)

10 in (~25.5 cm) 0.23 sec (230 ms)

12 in (~30.5 cm) 0.25 sec (250 ms)

17 in (~43 cm) 0.30 sec (300 ms)

24 in (~61 cm) 0.35 sec (350 ms)

31 in (~79 cm) 0.40 sec (400 ms)

39 in (~99 cm) 0.45 sec (450 ms)

48 in (~123 cm) 0.50 sec (500 ms)

69 in (~175 cm) 0.60 sec (600 ms)

Reflex Extension

•Compare boys vs. girls. On average, are the boys or girls faster? • Compare different ages. Who is fastest?...the older students or younger students? • Compare the scores after practice. Does reaction time improve with practice?

Choose one of the following…test at least 10 persons to answer the question.

Nervous System Clip

SENSORY SYSTEMS

• To survive, organisms must detect changes in the environment and react appropriately.

• To do this humans use SENSE ORGANS; eyes, ears, nose, mouth, and skin

• A SENSORY RECEPTOR is a neuron that detects stimuli (movement, pressure, tension, light, chemicals, temperature, etc)

SENSORY SYSTEMS Group Presentations

• Your table will be assigned a sensory system.• You must create a small poster of the system• You will give a 2 min presentation of the system • You will then give a 5 question quiz on the system to the class (the quiz can be done

orally or written on the board)• Quizzes will be graded and turned in for credit!

• Group Topics:• Vision• Sensory Receptors• Hearing• Balance• Smell and Taste• Touch• Your Choice!• Your Choice!

The Nervous System Crash Course

5 Senses Diagram

•Divide a paper into 5 parts•In each, describe the sense, include a minimum of 3 facts about the sense, why it is important

•Include 1 drawing or diagram for each•Add color!

Nervous System Coloring