Lesson Notes By Weeks and Term v4 - SHS 3
DISEASES AND DISORDERS
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DISEASES AND DISORDERS
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Subject: Biomedical Science
Class: SHS 3
Term: 1st Term
Week: 19
Grade code: 2.2.2.LI.2
Strand code: 2
Sub-strand code: 2
Content standard code: 2.2.2.CS.1
Indicator code: 2.2.2.LI.2
Theme: HUMAN BODY SYSTEMS
Subtheme: DISEASES AND DISORDERS
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The endocrine system acts as our body's chemical messaging service, using hormones to control everything from our mood and growth to our metabolism. When this system malfunctions, it can lead to serious diseases and disorders that affect a person's quality of life. In Ghana, conditions like goitre (often linked to the thyroid gland) and diabetes are well-known health challenges. Understanding how to recognise the signs of these problems is a critical skill for any student of biomedical science, as it is the first step towards diagnosis and treatment, improving health outcomes in our communities.
A. The Endocrine System: A Quick Refresher The endocrine system is a network of glands that produce and secrete hormones directly into the bloodstream. These hormones travel through the blood to target cells and organs, regulating many bodily functions. Gland: An organ that produces and releases substances (like hormones). Examples: Pituitary gland, Thyroid gland, Pancreas, Adrenal glands. Hormone: A chemical messenger that controls a specific function. For example, insulin from the pancreas controls blood sugar. Homeostasis: The body's ability to maintain a stable internal environment. The endocrine system is crucial for homeostasis. B. Focus Gland: The Thyroid Gland The thyroid is a butterfly-shaped gland located in the front of your neck, just below the Adam's apple ("totrɔfi" in Twi). Its main job is to control the body's metabolism. Metabolism: The process by which your body converts what you eat and drink into energy. Think of it as the engine of your body. Thyroid Hormones: The thyroid produces two main hormones: Thyroxine (T4) Triiodothyronine (T3) Function: These hormones tell the body's cells how fast to work and use energy. They affect almost every organ, controlling things like heart rate, body temperature, digestion, and how fast you burn calories. C. Endocrine Malfunction: Hyperthyroidism (Overactive Thyroid) Hyperthyroidism is a condition where the thyroid gland produces too much thyroxine (T4) and/or triiodothyronine (T3). Analogy: Imagine the accelerator pedal in a car is stuck down. The engine (your metabolism) runs too fast, burning through fuel quickly and causing many systems to become overworked.
Causes of Hyperthyroidism: Graves' Disease: An autoimmune disorder where the body's own immune system mistakenly attacks the thyroid, causing it to overproduce hormones. This is the most common cause. Thyroid Nodules: Lumps on the thyroid that can become overactive and produce excess hormones. Thyroiditis: Inflammation of the thyroid gland, which can cause stored hormones to leak out.
Symptoms and Physical Characteristics of Hyperthyroidism (And Why They Occur):
| Symptom / Characteristic | Scientific Explanation (Why it happens) | | -------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------- | | Unexplained Weight Loss (despite increased appetite) | The excess hormones cause a very high metabolic rate. The body is burning calories much faster than usual, leading to weight loss. | | Rapid or Irregular Heartbeat (Palpitations) | Thyroid hormones directly stimulate the heart muscle, making it beat faster and sometimes irregularly. | | Nervousness, Anxiety, and Irritability | The entire nervous system is overstimulated by the excess hormones, leading to a feeling of being constantly "on edge" or agitated. | | Tremors (usually a fine trembling in hands and fingers) | This is another sign of an overstimulated nervous system. | | Feeling Hot / Heat Intolerance & Increased Sweating | The high metabolic rate generates a lot of excess body heat. The body tries to cool down by sweating more. | | Goitre (An enlarged thyroid gland causing a swelling in the neck) | The gland may become enlarged due to the underlying cause (like inflammation or overstimulation in Graves' disease). This is a classic sign. | | Fatigue and Muscle Weakness | Although the body is "revved up," the constant high metabolic state and overstimulation eventually exhaust the body's resources. | | Changes in Menstrual Cycles (in females) | Hormones are all interconnected. Excess thyroid hormones can disrupt the balance of reproductive hormones. | | Bulging Eyes (Exophthalmos) | Specific to Graves' disease. The immune system attacks the tissues and muscles behind the eyes, causing them to swell and push forward. | D. A Contrasting Condition: Hypothyroidism (Underactive Thyroid) To understand hyperthyroidism better, it helps to know its opposite. Hypothyroidism is when the thyroid gland doesn't produce *enough* hormones. Analogy: The car's engine is running too slowly or idling. Everything slows down. Key Symptoms: Weight gain, fatigue, feeling cold, slow heart rate, depression, constipation. Notice how these are the direct opposites of hyperthyroidism symptoms.