Concise Summary of Neurological Functions and Disorders

Structures and Functions of the Nervous System

  • Divisions:
    • Central Nervous System (CNS)
    • Peripheral Nervous System (PNS)
  • Cells:
    • Neurons (responsible for transmitting impulses)
    • Glial cells (support, nourish, and protect neurons)
    • Neurogenesis (development of new neurons)

Nerve Impulse and Synapse

  • Nerve Impulse: Electrical signal traveling down a neuron
  • Action Potential: Rapid depolarization occurring when a neuron is stimulated above its threshold
  • Synapse: Junction between two neurons with three components: presynaptic terminal, synaptic cleft, post-synaptic receptor
  • Neurotransmitters: Chemicals facilitating impulse transmission across synapse

Central Nervous System (CNS)

  • Components:
    • Brain (cerebrum, brainstem, cerebellum)
    • Spinal cord (comprising ascending/descending tracts and motor neurons)
  • Reflex Arc: Neural pathway responsible for reflex actions

Peripheral Nervous System (PNS)

  • Components:
    • 31 pairs of mixed spinal nerves (sensory, motor, autonomic)
    • Cranial nerves (I-XII) with motor, sensory, and autonomic functions

Age-Related Considerations

  • CNS Changes:
    • Loss of neurons, decreased cerebral blood flow, and reduced CSF production
  • PNS Changes:
    • Decreased nerve conduction speed and sensory changes, but stable intellectual performance

Intracranial Pressure (ICP)

  • Normal Range: Typically 7-15 mmHg, can negatively affect cerebral blood flow if elevated
  • Monroe-Kellie Doctrine: Total cranial volume is constant; increase in one component must equal a decrease in another
  • Cushing's Triad: Signs indicative of increased ICP including hypertension, bradycardia, and abnormal respiration

Head Injuries

  • Types:
    • Scalp lacerations, skull fractures, concussions (minor)
    • More severe head trauma includes contusions and lacerations, leading to potential complications like hematomas

Brain Tumors

  • Types:
    • Primary tumors arising from brain tissue, secondary tumors from other body parts
  • Symptoms: Headaches, cognitive dysfunction, seizures, nausea

Meningitis (Bacterial and Viral)

  • Bacterial Meningitis: Acute infection; severe complications possible, often requires prompt antibiotic treatment
  • Symptoms: Severe headache, nuchal rigidity, fever, altered mental status
  • Viral Meningitis: Self-limiting, generally less severe than bacterial

Stroke Types and Management

  • Ischemic Stroke: 87% of strokes; caused by arterial blockage (thrombotic or embolic)
  • Hemorrhagic Stroke: Caused by blood vessel rupture (intracerebral/subarachnoid)
  • Management: Immediate medical attention crucial; thrombolytics for ischemic; supportive care for hemorrhagic

Parkinson's Disease (PD) and ALS

  • PD Symptoms: Bradykinesia, rigidity, tremor; progressive, affecting movement and coordination
  • ALS Symptoms: Muscle weakness, atrophy, no sensory impact; fatal disease with average lifespan post-diagnosis of 3-5 years
  • Management: Focus on symptom relief and quality of life

Huntington's Disease

  • Characteristics: Inherited neurodegenerative disorder leading to movement issues, cognitive decline, emotional disturbances; relentless progression
  • Diagnosis: Genetic testing; no skipping generations; symptom management is key