The Brain

Nervous System Nervous System contains: Brain, cranial nerves, spinal cord, spinal nerves, and peripheral nerves Function: coordinate and regulate the body’s responses

Basic Unit of the nervous system is a neuron Structure Dendrites – transmits impulses TO the cell Axon – transmits impulses AWAY from cell Function: cause body to react to its environment

2 types of neurons Sensory: in the skin and sensory organs Sends impulses from organs to the brain Motor: originate in brain & spinal cord Carries impulses to muscles and glands Example: Sensory detects heat Motor causes the body to move away

Central Nervous System (CNS) Brain Consists of the brain and spinal cord Brain Controls and coordinates body activities Weighs about 3 lbs Requires Oxygen and sugar to perform at its highest potential

The brain is surrounded by a protective barrier of membranes called the meninges 3 layers Innermost layer contains many blood vessels to “feed” the brain Between each layer is space

Brain has 4 hollow spaces (ventricles) Constantly produce Cerebrospinal Fluid Clear, colorless, watery fluid Flows through brain and spinal cord Provides protection and shock absorber Provides nourishment and removes different waste products Eventually becomes absorbed by veins

Parts of the Brain Brain consists of different parts: Cerebrum Cerebellum Brainstem Pons Medulla Oblongata Midbrain

Cerebrum Controls willful actions sensory messages Governs thought and speech Largest Part 2 halves (right and left) 2 layers: gray matter – outer, white matter - inner

Cerebellum Responsible for muscle coordination Tone, balance, and posture

Brainstem Midbrain Pons Medulla Oblongata Conducting impulses throughout brain Conduction of visual and auditory reflexes Pons Bridge between sections of brain Some reflex actions such as chewing and salivation Medulla Oblongata Controls involuntary actions Respiration, blood pressure, heartbeat, swallowing

Spinal Cord Function: conduct impulses (sends message) connect body parts to brain Protected by vertebrae, CSF, & meninges

Vocab Words CSF Meninges CNS Cerebrum Cerebellum Brainstem