1. UNIT 6: THE NERVOUS SYSTEM THE NERVOUS SYSTEM THE NEURON
THE PERIPHERAL NERVOUS SYSTEM
THE CENTRAL NERVOUS SYSTEM

2. THE NERVOUS SYSTEM
THIS SYSTEM HELPS COORDINATE ALL THE BODIES ACTIVITIES SO THEY WORK IN HARMONY
IT RECEIVES, PROCESSES, STORES, AND TRANSMITS INFORMATION FROM BOTH INSIDE AND OUTSIDE THE BODY
CENTRAL SYSTEM:
- BRAIN
- SPINAL CORD
PERIPHERAL SYSTEM:
- NERVES
- SENSORY RECEPTORS

3. THE NEURON 100 BILLION NEURONS (ON AVERAGE) ALSO CALLED “NERVE CELLS”
IT IS A SPECIALIZED NERVE CELL IN THE NERVOUS SYSTEM THAT RECEIVES AND TRANSMITS MESSAGES
MADE UP OF 4 PARTS
DENDRITES
CELL BODY (which contains the nucleus)
AXON
AXON TERMINALS

4. THE NEURON ROLE OF NEURONS:
TO PICK UP STIMULI
TRANSFORM THEM INTO NERVE IMPULSES
TRANSMIT THESE IMPULSES
STIMULUS: anything that can be perceived by a living organism and that can trigger a reaction. Sound, light, heat, electrical shocks, odours, hormones are all examples of stimuli.
NERVE IMPULSE: an electrical signal transmitted by a neuron
SYNAPSE: the transition zone between two neurons that allows a nerve impulse to be transmitted
NERVE: a structure that helps transmit information between the central nervous system and various regions of the body

5. TRANSMISSION OF NERVE IMPULSES
THE NEURON
CHARACTERISTICS
CAN BE STIMULATED: IT REACTS TO A STIMULUS BY CHANGING INTO AN ELECTRICAL SIGNAL (NERVE IMPULSE)
CONDUCTIVE. TRANSMITS NERVE IMPULSE FROM NEURON TO ANOTHER UNTIL IT REACHES TARGET
CONSUMES A GREAT DEAL OF OXYGEN AND GLUCOSE. CAN ONLY SURVIVE A FEW MINUTES WITHOUT OXYGEN
CAN LIVE MORE THAN 100 YEARS. PEOPLE KEEP THE SAME NEURONS THEIR ENTIRE LIFE
CANNOT REPRODUCE ITSELF, CANNOT BE REPLACED IF DESTROYED
TRANSMISSION OF NERVE IMPULSES
DENDRITES OF A NEURON RECEIVE MESSAGES OR STIMULI AND TRANSFORM THEM INTO NERVE IMPULSES
THE NERVE IMPULSES ARE THEN TRANSMITTED ALONG AXONS TO THE AXON TERMINALS
NERVE IMPULSES TRAVEL FROM ONE NEURON TO ANOTHER VIA NEUROTRANSMITTERS SECRETED BY AXON TERMINALS ACROSS A NARROW SPACE OR TRANSMISSION ZONE (SYNAPSE), BETWEEN TWO NEURONS.

6. THE PERIPHERAL NERVOUS SYSTEM
CONNECTS DIFFERENT PARTS OF THE BODY TO THE CENTRAL NERVOUS SYSTEM
INTERNAL/EXTERNAL MESSAGES
SENSORY RECEPTORS: PICK UP STIMULI AND TRANSFORMS THEM INTO NERVE IMPULSES
2 TYPES OF NERVES: sensory and motor
SENSORY NERVES: (5 SENSES + OTHERS)
TRANSMIT INFORMATION, THE FORM OF NERVE IMPULSES FROM THE SENSORY RECEPTORS TO THE CENTRAL NERVOUS SYSTEM
MOTOR NERVES:(MUSCLES + OTHERS)
TRANMSIT IMPULSES FROM THE CENTRAL NERVOUS SYSTEM TO THE MUSCLES IN ORDER TO PRODUCE VOLUNTARY AND INVOLUNTARY MOVEMENTS

7. THE CENTRAL NERVOUS SYSTEM
BRAIN: composed of the parts of the central nervous system located in the cranium
CEREBRUM
CEREBELLUM
BRAIN STEM
SPINAL CORD: the nervous system organ that carries information from/to the various parts of the body to/from the brain. It is also the reflex center
SPINAL NERVES
VERTABRAE

8. CEREBRUM COMMAND CENTER FOR ALL VOLUNTARY MOVEMENTS
INTERPRETATION OF THE SENSES
INTELLIGENCE
CENTER FOR EMOTIONS
DIVIDED INTO TWO HEMISPHERES (RIGHT / LEFT)
RIGHT: CONTROLS THE LEFT SIDE OF THE BODY
LEFT: CONTROLS THE RIGHT SIDE OF THE BODY
DIVIDED INTO 4 LOBES
FRONTAL, PARIETAL, OCCIPITAL, TEMPORAL
OUTER LAYER – CEREBRAL CORTEX (GREY MATTER)
- Muscle control, sensory perception, memory, speech
INNER LAYER – WHITE MATTER
- System connectedness

9. CEREBRUM FUNCTIONS FUNCTION DESCRIPTION EXAMPLE
CONTROLS VOLUNTARY MOVEMENTS
MOTOR CONTROL SENDS OUT NERVE IMPULSE TO STIMULATE MUSCLES TO CONTRACT
Stretching
Muscle use
Walking
Grasping
INTERPRETS MESSAGES PICKED UP BY SENSES
WHEN SENSES DETECT EXTERNAL STIMULUS THIS REGION INTERPRETS IMPULSE AND REACTS
Tactile reaction
Smelling
Reaction to light
CONTROLS INTELLIGENCE
PROBLEM SOLVING, READING, REASONING:ANY ACTIVITY ASSOCIATED WITH INTELLIGENCE
Thinking
Reflection
Reasoning
CONTROLS EMOTIONS
MANAGES EMOTIONS JOY, SAD, FEAR, ANGER, ETC
Laughing
Crying
REGULATES PHYSIOLOGICAL FUNCTIONS
HYPOTHALAMUS IS RESPONSIBLE FOR HUNGER, THIRST, ALERTNESS AND TEMPERATURE REGULATION. ALSO CONTROLS THE PITUITARY GLAND
hot/cold
Consciousness
Sweating

10. CEREBELLUM THE CENTER FOR BALANCE AND MOVEMENT COORDINATION EXAMPLES:
POSTURE
DANCE, RUN
MOTION SICKNESS, VERTIGO
SPEAK
DEXTERITY (PLAY PIANO)

11. BRAIN STEM
THE CONTROL CENTER OF INTERNAL STIMULI AS WELL AS INVOLUNTARY MOVEMENT
EXAMPLES:
INTERNAL MUSCLES (DIGESTIVE SYSTEM)
TWITCHING
SPASMS
RESPIRATION
BLINKING

12. THE SPINAL CORD
NERVOUS SYSTEM ORGAN THAT CARRIES INFORMATION FROM THE VARIOUS PARTS OF THE BODY TO THE BRAIN (AND VISE VERSA).
THE REFLEX CENTER
PROTECTED BY VERTEBRAE (BACK BONE)
REFLEX: A RAPID AND INVOLUNTARY RECTION TO A STIMULUS (GOOSE BUMPS)
REFLEX ARC: PATH TAKEN BY A NERVE IMPULSE DURING A RELFEX