Organization

Description:

The Nervous System is divided into the Central Nervous System and the Peripheral Nervous System. The central nervous system is made up of the brain and the spinal cord. The spinal cord is a long bundle of nervous tissue that extends from the brain and into the rest of the body. Its three jobs are to send motor information down itself, receive sensory information from the peripheral nervous system, and aid in reflexes. The peripheral nervous system consists of nerves and ganglia. Nerves are bundles of fiber that are in charge of sending and receiving messages, while ganglia are knots of cell bodies. The peripheral nervous system is divided into the sensory (or afferent) and motor (or efferent) divisions. The sensory division sends impulses towards the central nervous system regarding the senses. The motor division receives impulses from the central nervous system. The motor division is divided into the somatic nervous system and autonomic nervous system. The somatic nervous system is in charge of voluntary movement. The autonomic nervous system is divided into the sympathetic and parasympathetic divisions. The sympathetic division prepares the body for exerting energy, while the parasympathetic division conserves energy.

Diseases and Conditions

Schwannoma

A type of tumor that will not spread to other parts of the body. It occurs in the peripheral nervous system and develops in the Schwann cells located on the axon of a neuron.

Cerebral Palsy

There are four main types of this brain injury. Spastic leads to weak muscles in the limbs, Dyskinetic causes involuntary movement of limbs and the mouth, Ataxic leads to clumsy movement due to a lack of balance, and Mixed is a mix of all of them. It is caused by trauma, underdevelopment, and low oxygen in the brain, and is a permanent condition.

Huntington’s Disease

Autosomal Dominant disorder that affects a single gene and causes the nerve cells to break down overtime. It can lead to things such as memory loss, poor coordination, poor decision-making, and general confusion.

Morton’s Neuroma

A nerve tumor located specifically between the third and fourth toe and causes the coating of a nerve to thicken due to repeated friction.

Epilepsy

Genetics, trauma, tumors, or inflammation can cause epilepsy, which will result in seizures. Seizures are disruptions to electrical signaling and can lead to convulsions and a loss of consciousness.

Alzheimer’s Disease

This can be hereditary, but is most common in elders. It affects the signals that are sent via neurotransmitters and causes a loss of memory, or dementia. Some causes are the shrinking of the brain due to neuron death, blocking of food and energy for brain cells by neurofibrillary tangles, and amyloid plaques outside neurons affecting transmission of signals. It will first affect short term memory, and eventually other body functions.

Multiple Sclerosis (MS)

Damage to the myelin sheath that causes scars in the nerves. It may be an autoimmune disease, and there are three different types: Relapsing-remitting MS is the most common, Primary progressive MS causes gradual changes, and Secondary progressive MS gets worse independent from relapses.

Bell’s palsy

Paralysis of one side of the face due to a viral infection causing inflammation of nerves there. It causes difficulty eating, a drooping eyelid, drooling, and headaches.

Parkinson’s disease

Damage to cells that produce dopamine, which can affect elders. It leads to hand tremors, difficulty balancing, and stiff muscles. It can also cause memory loss and depression.

More Diseases: Motor Neuron Disease

Amyotrophic Lateral Sclerosis (ALS)

As a motor neuron disease, it leads to the weakening of muscles. Depending on where it occurs, it may cause a loss of function of moving, talking, or breathing. After receiving the disease, people will live around 5 more years.

Kennedy’s Disease

An X-linked disease that affects males reduces the effectiveness of androgen, so men with it will not receive enough testosterone, causing things such as larger breasts and fewer sperm cells.

Primary Lateral Sclerosis(PLS)

Similar to ALS, it is a motor neuron disease, but it only affects neurons in the brain. It commonly stiffens the limbs and generally starts after the age of 40.

Spinal Muscular Atrophy

Defects in the SMN1 gene lead to a lack of SMN proteins and affects children at different ages.

Type 1, called Werdnig-Hoffman disease begins at 6 months of age, and children are unable to sit up due to floppy muscles, or hypotonia.
Type 2 occurs between 6 and 12 months, and children with it may not be able to stand, walk, or breathe properly.
Type 3 is also called Kugelberg-Welander disease occurs between 2 and 17 years of age and causes difficulty with climbing stairs and may cause scoliosis.
Type 4 happens after 30 years of age, leading to spasms and breathing issues.

Progressive Muscular Atrophy

Infecting the spinal cord, it causes weakness in one’s hands, which spreads through the body, leading to cramps.

Progressive Bulbar Palsy (PBP)

Motor neurons specifically in the brain stem are damaged, affecting one’s ability to have normal mouth functions such as speaking and chewing. It will also affect emotions, with unexpected crying or laughing.