Disorders, Injuries, and Effects of Drugs on the Nervous System (Grade 12 NSC Matric Life Sciences): Revision Notes
Disorders, Injuries, and Effects of Drugs on the Nervous System
The nervous system can be affected by various problems including diseases, physical injuries, and chemical substances like drugs. Understanding these issues is important for recognising how they impact normal body functions and quality of life.
These conditions can have profound effects on a person's ability to function independently and significantly impact their family and caregivers.
Major nervous system disorders
Alzheimer's disease
Alzheimer's disease is a serious brain condition that gradually destroys brain cells over time. This makes it what scientists call a neurodegenerative disease, meaning the damage cannot be reversed once it starts.
Critical Facts About Alzheimer's:
- The disease is completely irreversible once it begins
- Currently has no cure available
- Symptoms can only be managed, not stopped or reversed
Key characteristics:
- The exact cause remains unknown to medical researchers
- Most commonly appears after age 60, though it can affect people as young as 40
- Currently has no cure, but symptoms can be managed with proper treatment
Main symptoms include:
- Progressive memory loss that worsens over time
- Confusion and difficulty with everyday tasks
The disease severely impacts patients' ability to live independently and places significant strain on families and caregivers.
Multiple sclerosis
Multiple sclerosis is an autoimmune condition that typically develops in younger adults, usually between 20 and 40 years old. In this disease, the body's own immune system mistakenly attacks the protective covering around nerve fibres called the myelin sheath. When this protective layer is damaged, nerve signals cannot travel properly throughout the body.
Understanding Autoimmune Attack: The body's immune system, which normally protects us from disease, mistakenly identifies the myelin sheath as a threat and attacks it. This is why it's called an autoimmune disease.
Key characteristics:
- The underlying cause is not fully understood
- No cure exists, but medications can help manage symptoms
- Affects the central nervous system's ability to communicate effectively
Common symptoms include:
- Loss of speech and vision problems
- Difficulty with walking and coordination
- Chronic pain throughout the body
- Persistent fatigue
- Memory problems and cognitive difficulties
Injuries to the nervous system
Physical trauma to the brain and spinal cord represents one of the most serious health challenges. Motor vehicle accidents are the leading cause of these devastating injuries, though they can result from various other incidents.
Severity of Nervous System Injuries: These injuries are among the most serious medical emergencies because nerve tissue cannot regenerate like other body tissues. The effects are often permanent and life-changing.
Brain injuries
When the brain is damaged, the effects depend heavily on which specific area is injured. Different brain regions control different functions, so injury consequences vary widely between patients.
Potential effects include:
- Problems with movement and coordination
- Memory difficulties and learning problems
- Speech and communication issues
- In severe cases, long-term mental health complications
Spinal cord injuries
Damage to the spinal cord often results in more predictable but equally serious consequences. The spinal cord serves as the main pathway for messages between the brain and the rest of the body.
Common outcomes:
- Paralysis (inability to move) in affected areas
- Loss of sensation below the injury site
- Complete inability to feel or move anything below the damaged area
Treatment approaches
Currently, medical science cannot regenerate damaged nerve tissue. However, several approaches can help patients recover some function:
- Physical therapy: Helps maintain muscle strength and flexibility
- Occupational therapy: Teaches new ways to perform daily activities
- Future possibilities: Researchers are investigating stem cell therapy as a potential treatment for spinal cord injuries and degenerative diseases like multiple sclerosis and Parkinson's disease
Effects of drugs on the nervous system
Note: This section is not examinable but provides important health information.
Drugs interfere with the normal functioning of the central nervous system by changing how nerve signals are transmitted. They primarily affect the speed at which neurotransmitters (chemical messengers) can cross the gaps between nerve cells at synapses.
How drugs cause problems
Different types of drugs (such as marijuana, ecstasy, heroine, or tik) stimulate either the sympathetic or parasympathetic nervous system more than normal. This excessive stimulation disrupts the body's natural balance.
Dangerous Side Effects of Drug Use: Drug use can cause life-threatening health problems that may require emergency medical treatment. These effects can occur even with first-time use.
Common side effects include:
- Reduced coordination and motor skills
- Increased heart rate beyond safe levels
- Dangerously elevated blood pressure
- Decreased appetite leading to malnutrition
- Hallucinations and paranoid thoughts
Key Points to Remember:
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Alzheimer's disease gradually destroys brain cells and mainly affects older adults, causing memory loss and confusion
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Multiple sclerosis occurs when the immune system attacks the protective covering of nerves, typically affecting young adults aged 20-40
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Nervous system injuries from accidents can cause paralysis and loss of sensation, with spinal cord damage often having more predictable effects than brain injuries
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Drugs disrupt normal nerve signal transmission and can cause dangerous side effects like increased heart rate, high blood pressure, and mental health problems