The Nervous System The Nervous System Functions of

The Nervous System

The Nervous System

Functions of the Nervous System ► Sense environment; react to it ► Learn; apply what is learned ► Store, recall memories ► Regulate body metabolism

Two main parts of the Nervous System ► Central Nervous System (CNS) ► control center of the body - brain & spinal cord ► Peripheral Nervous System ► Nerve network branches off the CNS; connects with organs in the body ► sensory nerves; motor nerves

“peri-” ► “about” ► “around” ► “beyond”

The Nervous System Central Nervous System Peripheral Nervous System – nerves that connect all areas of your body to the CNS Brain Spinal Cord Sensory Motor Neurons – cause Neurons – muscles to move Medulla – sense changes controls blood inside/outside pressure, heart body rate Cerebellum – coordinates/balances actions of muscles; involuntary Cerebrum- largest region, interprets sensory info (taste, touch etc. ; voluntary) Right hemisphere - controls left side of body; creative Left hemisphere – controls right side of body; analytical

Parts of the Brain Part ► Cerebrum ► Cerebellum ► Medulla Function Largest section of brain; interprets sensory information, conscious thought; learning, creativity, memory, decision- making, voluntary actions Below & behind cerebrum; coordination (including learned behaviors; walking, writing) VOLUNTARY ACTIONS Where brain & spinal cord meet. Controls internal organs, some reflexes INVOLUNTARY ACTIONS ► Hypothalamus At base of cerebrum. Regulates hormone production, body temp. , blood pressure

THE BRAIN

Types of Action Voluntary Definition Examples Action you can control (cerebrum & cerebellum) Involuntary Actions you can not control, these happen automatically (medulla & hypothalmus) Touch, walking, Breathing, running, playing heartbeat, tennis etc. digestion, hormones

Neuron (nerve cell)

THE NEURON The neuron is the functional unit of the Nervous System ► We have over 100 BILLION neurons in our brain alone!!! ►

THE NEURON ► Vary in size and shape. All have the following: Dendrites: receives information ► Cell Body: contains nucleus, organelles ► Axon: sends info. away from the cell body ►

The Synapse. Transmission of an Impulse Axons and dendrites do not touch. Nerve signals have to jump across a tiny gap. They change from electrical signals into chemical signals, then back into electrical signals.

Nervous System Disorders DISEASE: POLIO CEREBRAL PALSY MENINGITIS PROBLEM: Viral infection Attacks nerve cells Damage to brain parts that control movement Inflammation of meninges (membranes covering the brain) – Viral or bacterial EFFECTS: Nervous system damage Can cause paralysis (Vaccine eliminated polio in the USA) Difficulty writing, walking, maintaining balance Can cause death