Nervous System

Nervous System

The nervous system is the

communication network for the

body.

The main function of the nervous

system is to coordinate all of

the body’s activities.

Neurons

Neuron, or nerve cell.

•Dendrites

•Axons

•Myelin sheath.

•Synapse

How do message travel across synapses?

Types of Neurons

• Afferent

• Efferent

• Associative

Divisions of the Nervous System

• Central nervous system

• Peripheral nervous system

– Autonomic nervous system

– Somatic nervous system

Central Nervous System: Brain

• Cerebrum

• Diencephalon

▫ Thalamus

▫ Hypothalamus

• Cerebellum

Central Nervous System: Brain (Continued)

• Brain stem ▫ Midbrain

▫ Pons

▫ Medulla oblongata

Brain video

Ted Talk

Central Nervous System: Spinal Cord

• Controls many reflex actions

• Pathway for messages to and from the brain and the nerves that go to the muscles and glands.

Central Nervous System: Protection

• Brain is protected by the skull

• Spinal cord is protected by the vertebrae

• Meninges cover and protect the brain and spinal cord:

▫ Dura mater

▫ Arachnoid

▫ Pia mater

• Cerebrospinal fluid

Peripheral Nervous System

• Cranial nerves

– 12 pairs and branches

• Spinal nerves

– 31 pairs and branches

Autonomic Nervous System

• Autonomic nervous system controls the involuntary, or automatic, activities of the body

• Sympathetic system

• Parasympathetic system

Diseases and Disorders of the Nervous System

• Shingles

• Myasthenia Gravis

• Cerebrovascular Accidents

• Multiple Sclerosis

Myasthenia Gravis

• a disease where the proper nerve pulses are not sent to the muscles. As a result, progressive muscle weakness and paralysis occur. If the respiratory muscles are affected, the disease can be fatal.

• The exact cause is not known, but it is thought that it may be related to an autoimmune process.

• There is no cure. Treatment involves medication and lifestyle changes to cope with the disease.

Ptosis

Drooping of one or both eyelids often seen in patients with Myasthenia Gravis

Shingles

• Affects mainly the elderly, or those with weakened immune systems.

• Anyone who has had Chicken pox in the past is susceptible to Shingles

• During an outbreak, the varicella virus( which has been dormant in the nervous system) travels to the skin along a dermatome. Shingles virtually always appears along a single dermatome on one side of the body.

Shingles rash

Note how the rash follows one dermatome

Cerebral Vascular Accident (CVA) or Stroke

• It occurs when there is a loss of blood flow, and in turn oxygen, to the brain.

• It may be caused by a blood vessel bursting or being blocked by a blood clot.

• Symptoms vary depending on the area and the amount of brain tissue damaged. Common symptoms include weakness or paralysis on one side of the body, difficulty swallowing, visual or speech impairment, mental confusion, and loss of consciousness.

• Stroke is a leading cause of death in the United States. Controlling risk factors, such as smoking, heart disease, and diabetes, helps to prevent them.

• Treatment within the first three hours of a stroke, such as using drugs to break up a clot and restore blood flow, can help to prevent brain damage. Treatment for any damage involves therapy to help people recover from or adapt to the losses of mental or physical function.

Multiple Sclerosis

• a disease of the central nervous system that results in progressive loss of muscle control. The myelin sheath is slowly destroyed.

• The exact cause of this disease is not known, but it is thought that it may be related to a virus or an autoimmune process.

• Early symptoms include double vision, tingling and numbness, weakness, and fatigue. As the disease worsens, symptoms include tremors, speech impairment, and paralysis.

• There is no cure. Treatment involves medication and physical therapy to help control the symptoms and maintain functional ability as long as possible.

CTE

• Chronic Traumatic Encephalopathy

• League of denial https://www.youtube.com/watch?v=6RfoDFP1VCE