The Nervous System
The nervous system is made of 2 parts: The CNS (central nervous system) Consists of the brain and spinal cord
The PNS (peripheral nervous system) consists of nerves outside the brain and spinal cord
The Central Nervous System Brain The brain is a large mass of neurons located in the cranial cavity and is protected by the skull and 3 tough layers called the meninges Fluid called cerebrospinal fluid is found between the layers to further protect the brain
Parts of the Brain Cerebrum- large folded part of the brain It is the center for voluntary action Where sensory impulses are interpreted Where motor activities are initiated Where thinking, memory and reasoning occur
Cerebellum Lower back part of the brain Coordinates motor activities and helps to maintain balance
Medulla Oblongata Located below the cerebellum Controls involuntary activity like: Breathing, sneezing, heartbeat, blood pressure, coughing, peristalsis
Spinal Cord Carries impulses between the brain and the body It is protected by the vertebrae It is the center for reflex action
The Peripheral Nervous System Has 2 parts: The somatic: Controls voluntary muscles
The autonomic controls involuntary muscles of the heart, digestive tract , diaphragm etc.
The autonomic nervous system has 2 parts: Sympathetic : accelerates body activities Parasympathetic : slows down body activities
Malfunctions of the Nervous System Cerebral palsy Damage to motor centers of the brain before or during birth ; causes poor muscle coordination and speech difficulties
Meningitis Inflammation of the membranes surrounding the brain and spinal cord Can be viral or bacterial
Stroke Damage to the nerves in a particular part of the brain due to blockage or rupture of blood vessels, which prevents oxygen from reaching the brain cells May result in paralysis, memory or speech loss or blindness
Polio Viral disease of the nervous system May cause paralysis Prevented by immunization
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