Hansen's disease, also known as leprosy, arises when bacteria infect the Schwann cells that wrap around axons of peripheral nerves to form a myelin .shealth. Attacks by the immune system on the bacteria-infected glial cells causes a loss of myelin in peripheral nerves. How is Hansen's disease similar to multiple sclerosis? Why do the symptoms differ? Why are people with Hansen's disease unusually prone to injuring themselves?

To explain:How is Hansen’s disease similar to multiple sclerosis.

Concept introduction: Most of the vertebrate axons have a myelin sheath. It is a discontinuous covering composed of myelin-producing glial cells that wrap around the axon one after another. In the peripheral nervous system, the myelin sheaths are formed by glial cells called Schwann cells. Myelin is a fatty material that functions as insulation.

Multiple sclerosis is a nervous disorder that arises when a person’s immune system mistakenly attacks and destroys myelin in the brain and spinal cord. The myelin is replaced by scar tissue, so that the speed of the action potential declines. This results in weakness, fatigue, impaired coordination, numbness, and vision problems...

To explain:The reason that Hansen’s disease and multiple sclerosis have differentsymptoms.

Concept introduction: Most of the vertebrate axons have a myelin sheath. It is a discontinuous covering composed of myelin-producing glial cells that wrap around the axon one after another. In the peripheral nervous system, the myelin sheaths are formed by glial cells called Schwann cells. Myelin is a fatty material that functions as insulation.

To explain: The reason that people with Hansen’s disease are unusually prone to injure themselves.

Concept introduction: Most of the vertebrate axons have a myelin sheath. It is a discontinuous covering composed of myelin-producing glial cells that wrap around the axon one after another. In the peripheral nervous system, the myelin sheaths are formed by glial cells called Schwann cells. Myelin is a fatty material that functions as insulation.