Introduction

The Grade 12 syllabus for this chapter focuses on the concepts of cardiovascular disorders, respiratory disorders, renal disorders, and substance abuse involving drugs, alcohol and smoking.

1. Cardiovascular Disorders

Cardiovascular disorders affect the heart or blood vessels. They may interfere with blood flow, oxygen delivery or normal pumping activity of the heart.

1.1 Hypertension

Hypertension means persistently elevated arterial blood pressure. Long-standing high pressure can increase stress on blood vessels, heart and other organs.

1.2 Atherosclerosis and Coronary Artery Disease

Atherosclerosis is the buildup of lipid-rich plaques within arterial walls. When coronary arteries are affected, blood supply to heart muscle can be reduced.

1.3 Heart Attack

A heart attack or myocardial infarction occurs when blood flow to part of the heart muscle becomes critically blocked long enough to injure or kill cardiac tissue.

2. Respiratory Disorders

Respiratory disorders affect airways, lungs or gas exchange and can reduce the efficiency with which oxygen enters and carbon dioxide leaves the body.

2.1 Asthma

Asthma involves episodes of airway narrowing and inflammation. During an episode, smooth muscle constriction, airway swelling and mucus can reduce airflow.

2.2 Chronic Obstructive Pulmonary Disease (COPD)

COPD is a long-term condition in which airflow becomes persistently limited. Tobacco smoke is an important preventable risk factor. Chronic bronchitis and emphysema are major patterns associated with COPD.

2.3 Respiratory Infection and Air Pollution

Respiratory health may also be affected by infectious disease and exposure to pollutants. Smoke and particulate matter can irritate airways and worsen respiratory symptoms.

3. Renal Disorders

Renal disorders affect the kidneys or urinary system and can interfere with filtration, water and electrolyte regulation, acid-base balance and waste removal.

3.1 Kidney Stones

Kidney stones are hard crystalline deposits that can form within the urinary system. A stone may cause severe pain if it obstructs urine flow.

3.2 Renal Failure

Renal failure means the kidneys are unable to perform their normal functions adequately. Severe failure can cause accumulation of wastes and disturbances of fluid, electrolyte and acid-base balance.

4. Drug Abuse

Possible Consequences

• Dependence and loss of control over use.
• Impaired judgment and coordination.
• Damage to organs depending on substance and exposure.
• Academic, occupational, family and social problems.
• Risk of injury, poisoning and unsafe behaviour.

5. Alcohol Abuse

Alcohol is a psychoactive depressant. Harmful use can impair judgment and coordination and, with repeated heavy exposure, can damage multiple organ systems and contribute to dependence.

Effects

• Reduced reaction time, coordination and judgment.
• Greater risk of accidents and injuries.
• Long-term damage to liver and other organs with chronic harmful use.
• Dependence and social or family problems.
• Risk to fetal development if alcohol is consumed during pregnancy.

6. Smoking and Tobacco Abuse

Tobacco smoke contains nicotine and many toxic or carcinogenic substances. Smoking damages the respiratory and cardiovascular systems and increases the risk of serious disease.

7. Prevention and Healthy Behaviour

• Avoid smoking, vaping and harmful substance use.
• Avoid misuse of medicines and other drugs.
• Maintain regular physical activity appropriate to age and health.
• Eat a balanced diet and limit excess salt, trans fats and highly processed foods.
• Maintain healthy sleep and stress-management habits.
• Attend health screening when medically recommended.
• Seek qualified help early for substance dependence or persistent symptoms.

8. Quick Revision & Exam Points

One-Minute Revision

• Cardiovascular disorders affect heart and blood vessels.
• Hypertension = persistently high blood pressure.
• Atherosclerosis narrows arteries through plaque buildup.
• Asthma causes episodic airway narrowing and inflammation.
• COPD produces persistent airflow limitation.
• Renal disorders impair kidney or urinary-system function.
• Kidney stones can obstruct urine flow.
• Renal failure reduces kidney function.
• Drug abuse can cause dependence and health damage.
• Alcohol impairs coordination and judgment.
• Smoking damages lungs and cardiovascular health.