The nervous system

1. NERVOUS SYSTEM
BY KATRINA PARKER

2. THE THREE MAIN ORGANS
• BRAIN- COORDINATES BODY FUNCTIONS
• NERVES- TRANSMIT MESSAGES TO AND FROM THE CENTRAL
NERVOUS SYSTEM
• SPINAL CORD- TRANSMITS MESSAGES TO AND FROM THE BRAIN

3. NERVOUS TISSUE
• AXON
• DENDRITES
• MYELIN
• NERVE CELL BODY
• NEUROGLIAL CELLS
• NEURON
• NEUROTRANSMITTER
• SYNAPSE
• SYNAPTIC CLEFT
NEURONS

4. NERVOUS TISSUE
IT’S TWO TYPES OF CELLS THAT THE NERVOUS TISSUE CONSISTS OF: NEURONS
AND NEUROGLIAL CELLS. NEURONS HAVE THREE BASIC PARTS, DENDRITES ARE
WHERE THE INFORMATION IS RECEIVED, NERVE CELL BODY CONTAINS THE
NUCLEUS AND IS WHERE THE INFORMATION GOES TO MAKE DECISION, AND AXON
IS WHERE THE INFORMATION GOES THROUGH TO IT’S DESTINATION. WHEN THE
AXON MEETS WITH ANOTHER DENDRITE ITS CALLED SYNAPSE. THE MYELIN IS A
FATTY SUBSTANCE THAT ACTS AS INSULATION FOR THE AXON SO IT CAN SEND
INFORMATION FASTER.

5. CENTRAL NERVOUS SYSTEM (CNS)
• THE CENTRAL NERVOUS SYSTEM IS ABOUT THE BRAIN AND THE SPINAL CORD
AND ABLE TO RECEIVE IMPULSES FROM ALL OVER THE BODY. THIS SYSTEM HAVE
BOTH GRAY AND WHITE MATTER.
• GRAY MATTER IS NONMYELINATED NEURON CELL BODIES AND DENDRITES. ITS
FOUND IN THE OUTER PART OF THE BRAIN AND THE INNER PART OF THE SPINAL
CORD.
• WHITE MATTER IS MYELINATED NERVE FIBERS MOSTLY AXONS. IT’S FOUND IN
THE INNER PART OF THE BRAIN AND THE OUTER PART OF THE SPINAL CORD.

6. BRAIN
THE CEREBRUM HAS FOUR LOBES
• FRONTAL LOBE CONTROLS MOTOR FUNCTION, PERSONALITY AND SPEECH
• PARIETAL LOBE RECEIVES AND INTERPRETS NERVES IMPULSES FROM SENSORY RECEPTORS AND
INTERPRETS LANGUAGE.
• OCCIPITAL LOBE CONTROLS THE VISION
• TEMPORAL LOBE CONTROLS HEARING AND SMELL
THE BRAIN STEM CONSISTS OF THREE PARTS
• MIDBRAIN
• PONS
• MEDULLA OBLONGATA

7. SPINAL CORD
THE SPINAL CORD PROVIDE A PATHWAY FOR IMPULSES TRAVELING TO AND FROM
THE BRAIN. IT STARTS FROM THE MEDULLA OBLONGATA OF THE BRAIN DOWN TO
THE SECOND LUMBAR VERTEBRA WITHIN THE VERTEBRAL COLUMN. THE SPINAL
CAVITY OR VERTEBRAL CANAL ARE OTHER NAMES FOR THE SPINAL CORD, THERE
ARE 33 VERTEBRAE OF THE BACKBONE. THE SPINAL CORD IS PROTECTED BY THE
CEREBROSPINAL FLUID THAT FLOWS DOWN THE CENTER OF THE SPINAL CORD
THROUGH THE CENTRAL CANAL.

8. PERIPHERAL NERVOUS SYSTEM
THIS SYSTEM INCLUDES 12 PAIRS OF CRANIAL NERVES AND THE 31
PAIRS OF SPINAL NERVES. AFFERENT NEURONS ALSO CALLED
SENSORY NEURONS THAT CARRIES INFORMATION FROM SENSORY
RECEPTOR TO THE CNS. EFFERENT ALSO CALLED MOTOR NEURONS
CARRIES ACTIVITY INSTRUCTIONS FROM THE CNS TO MUSCLES OR
GLANDS OUT IN THE BODY.
IT HAS TWO AUTONOMIC NERVOUS SYSTEM
• PARASYMPATHETIC NERVES SERVES AS A COUNTERBALANCE FOR
THE SYMPATHETIC NERVES, THE “REST-AND-DIGEST” REACTION.
WHICH CAUSE THE HEART RATE TO SLOW DOWN, LOWER BLOOD
PRESSURE AND STIMULATE DIGESTION.
• SYMPATHETIC NERVES CONTROL THE “FLIGHT-OR- FLIGHT”
REACTION DURING TIMES OF STRESS AND CRISIS. THESE NERVES
INCREASE THE HEART RATE DILATE AIRWAYS, INCREASE BLOOD
PRESSURE ETC.