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The Nervous System. Functions of the Nervous System. 1. Communication and coordination Adapt and respond to changes from both inside and outside the body 2. Site of reasoning- your brain 3. Two main divisions Central nervous system (CNS): brain and spinal cord
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Functions of the Nervous System • 1. Communication and coordination • Adapt and respond to changes from both inside and outside the body • 2. Site of reasoning- your brain • 3. Two main divisions • Central nervous system (CNS): brain and spinal cord • Peripheral nervous system- the nerves
Neuron- basic structural unit of the nervous system • Dendrites- carry impulses towards the cell • Axon-carry impulses away from the cell • Myelin sheath • Synaptic terminal • Epinephrine • Norepinephrine • Acetylcholine
Nerves are made of many nerve cells • Afferent-sensory nerves carry message to brain • Efferent-motor neurons carry message from brain to muscle • Associate- do both • Heads up
Central nervous system • Brain and spinal cord
Cerebrum-largest part of brain. Responsible for reasoning, thought, memory, speech, sensation, etc. • Divided into two halves. • Further divided into lobes; occipital, parietal, temporal and frontal
Cerebellum-responsible for muscle coordination • Brain stem- most basic functions; respiration, swallowing, blood pressure. Lower part (medulla oblongata) is continuous with spinal cord
Spinal cord- begins at foramen magnum and ends at second lumbar vertebrae • Contains both afferent (to the brain) and efferent (motor neurons- away from the brain)
Both the brain and spinal cord are covered by a membrane system called the meninges • In addition, the brain has four hollow areas called ventricles. Cerebrospinal fluid is produced in the ventricles and baths the brain and spinal column
Peripheral nervous system • Somatic system • 12 pairs cranial nerves • 31 pairs spinal nerves • Autonomic • Sympathetic • Fight or flight • Parasympathetic
Disorders of the nervous system • Meningitis- inflammation of the linings of the brain and spinal cord • Encephalitis- inflammation of the brain • Epilepsy-seizure disorder. Excessive discharge from neurons. 1 in 200 suffer. Grand mal or petit mal seizures • Cerebral palsy- disturbance in voluntary muscular action • Parkinson’s –decreased neurotransmitter • MS multiple sclerosis- autoimmune