PERIPHERAL NERVOUS SYSTEM (PNS) and COMMON DISORDERS

PERIPHERAL NERVOUS SYSTEM (PNS)

·         A relay system that detects changes in both the internal and external environments and relays this information to the central nervous system (CNS).

·         Transmits impulses from the brain and spinal cord to the appropriate end organs (muscles, glands, etc.).

Decrease in neurons, neurotransmitters, dendrites, and synapses

·         → leads to brain atrophy.

·         Impairments in:

o    General muscle strength

o    Reflexes

o    Nerve conduction velocity

o    Motor skills (slowed)

o    Balance and coordination (deficits)

Changes in autonomic regulation

·         → compromised thermoregulation.

o    Decreased temperature sensitivity → risk of hypothermia / hyperthermia.

PARKINSON’S DISEASE

·         A progressive disease that affects nerve cells in the brain, causing tremors, poor coordination, walking and movement problems.

DEMENTIA (Permanent or Progressive Organic Mental Disorder)

·         Characterized by:

o    Personality changes

o    Confusion, disorientation

o    Deterioration of intellectual functioning

o    Impaired control of memory, judgment, impulses

·         Mild Dementia

Stages of Dementia

o    Able to function independently

o    Occasional forgetfulness, confusion, lapses in judgment

·         Moderate Dementia

o    May require assistance with daily activities

o    Greater memory loss

o    Additional symptoms, including sundowning

·         Severe Dementia

o    Requires round-the-clock care

o    Loss of mobility

o    Difficulty performing basic functions (e.g., swallowing)

ALZHEIMER’S DISEASE (Senile Dementia, Alzheimer Type)

·         Most common form of dementia.

·         Typically seen in individuals older than 65 years.

·         Chronic, progressive, degenerative disease with:

o    Brain cell and tissue atrophy

o    Beta-amyloid plaques

o    Neurofibrillary tangles

·         Neurotransmitter changes:

o    Decreased acetylcholine → impaired reasoning, memory, learning

o    Decreased norepinephrine and dopamine

TRANSIENT ISCHEMIC ATTACK (TIA)

·         Brief episodes of cerebrovascular insufficiency.

·         Usually due to cerebral blood vessel obstruction (caused by embolus or atherosclerotic plaque).

·         More common in middle-aged and older adults.

·         Episodes:

o    Occur without warning

o    Last a few minutes (some may persist up to 24 hours)

Cerebrovascular insufficiency

broad term for conditions that reduce blood flow to the brain, leading to strokes or transient ischemic attacks (TIAs)

STROKE (Cerebrovascular Accident, CVA)

·         A disturbance of blood supply to the brain.

·         Causes include:

o    Atherosclerosis

o    Hypertension

o    Diabetes

o    Or combination of these risk factors

·         Can occur at any age, but most common in those >65 years.

·         Stroke fatality risk increases with age.

·         Occurs slightly more in men than women.

Even when not fatal, it is a leading cause of disability