Nervous System Central Nervous System: consists of

the brain and spinal cord. It reacts to internal and external stimuli.

Peripheral Nervous System: Consists of neurons. It carries messages to and from the central nervous system.

Autonomic Nervous System: Consists of neurons. It carries impulses that regulate involuntary activities and release of hormones.

Neuron Neuron: The basic unit of structure and

function in the nervous system. It consists of 3 parts. 1) The cell body contains the nucleus

and organelles of the cell. 2) The dendrites are branching fibers

that carry impulses toward the cell body.

3) The axons are long fibers that carry impulses away from the cell body.

Neuron

Mylin: Some neurons have a fatty mylin sheath that serves as insulation.

Nerves The nervous system is made up of

3 types of nerves. 1) Sensory nerves carry impulses to

the spinal cord and brain. 2) Motor nerves carry impulses

from the central nervous system. 3) Interneurons (Association

neurons): located in the brain and spinal cord. Carry impulses from sensory neurons to motor neurons.

Nerve Impulses

Nerve impulse: an electrical signal that moves along a neuron.

Synapse: The gap between an axon and a dendrite.

Neurotransmitter: chemical that is released by the axon at the synapse in order to stimulate the dendrite or muscle tissue.

The Brain

Meninges: a series of three membranes that surround and protect the brain.

Cerebrum: The largest part of the brain. It is divided into 2 hemispheres.

The left hemisphere controls the right side of the body. It controls the use of language, math and logical thinking.

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The Brain

The right hemisphere controls the left side of the body. It controls musical and artistic abilities as well as emotions.

The outer surface is made of gray matter. It consists of nerve cell bodies.

The inner surface is made of white matter. It consists mostly of axons.

The Brain The cerebellum is located below the

cerebrum. It controls balance and coordination, as well as involuntary activities.

The medulla oblongata connects the brain to the spinal cord, thus it is called the brain stem. It maintains breathing and the heart rate. It controls coughing, sneezing and swallowing.

The Brain Thalamus: Oval structure located in

about the middle of the brain. It interprets pain, temperature and pressure.

Hypothalamus: Located below the thalamus. Despite its small size, it controls many body activities, most of them related to maintaining homeostasis. It regulates the endocrine (hormonal) system.

Spinal cord

The spinal cord connects the brain to the rest of the nervous system.

The reflex arc is a pattern of stimulus and response that involves sensory impulses to the spinal cord and out going motor impulses to the muscles.

Disorders of the Nervous System

Cerebral palsy: A group of nonprogressive nerve disorders caused by damage to motor areas of the brain during fetal life, birth, or infancy.

Meningitis: Inflamation of the meninges.

Polio: viral infection that may result in the destruction of motor neurons leading to paralysis.

Disorders of the Nervous System

Multiple Sclerosis: The progressive destruction of the mylin sheaths. Leads to progressive loss of motor control.

Epilepsy: This is the second most common neurological disorder after stroke. Results in epileptic seizures initiated by abnormal discharges of impulses from the neurons in the brain.