The Nervous System!

Controls all other systems!!!

Main Function of the Nervous System• To receive stimuli from inside and outside of

the body, to interpret the stimuli, and initiate responses for survival.

Division of the Nervous System

• Central Nervous System (CNS)– Brain– Spinal Cord

• Peripheral Nervous System (PNS)– Peripheral nerves– Somatic and Autonomic Systems

Central Nervous System (CNS)

• Organ functions– Brain: coordinates all of the body’s activities– Spinal cord: connects the brain to the peripheral

nerves Jellyfish have no

brain!

Human

Sheep

Cat

The Brain• Cerebrum: Controls thoughts, voluntary actions, and

sensations related to five senses.

• Cerebellum: Coordinates *voluntary muscle* movements and balance.

• Brain stem: Located at the base of the brain and controls vital and *involuntary* processes (ex’s: breathing, heart beat, and digestion)

• Fun fact: It weighs about 3 lbs

Human

Sheep

Cat

Cerebrum

Cerebellum

Brain stem

Spinal Cord• A bundle of nerves that begins at the brain

stem and connects to the peripheral nerves • Vertebrae protect the spinal cord

Central Nervous System (CNS)Organs and Functions

Brain Spinal Cord

Peripheral Nervous SystemConnects the brain and spinal cord to other bodyparts.

Communication is Key

• How does the nervous system communicate?• Neurons and neurotransmitters

Terminal Button

Reflexes• An involuntary, automatic response to a

stimulus.• Reflex arc

Examples of Reflexes

• *Knee jerk (helps stand upright)• *Blinking (protects eyes; cleans them)• *Arm raise (protects face)• Coughing (clears airways when irritated)• Sneezing (clears airways when irritated)• Goosebumps (warm up body) • Shivering (warm up body)

Music Video Time!

• http://www.youtube.com/watch?v=40EBLb1avhM&feature=player_detailpage