Chemical Coordination Exercise Solutions | KalviGavani

| Feature | Endocrine Glands | Exocrine Glands | |---|---|---| | Ducts | Ductless (no ducts) | Have ducts | | Secretion | Hormones into blood | Enzymes/sweat through ducts | | Target | Distant organs (via blood) | Local surface | | Speed | Slow, long-lasting | Fast, short-lasting | | Examples | Pituitary, thyroid, adrenal | Sweat glands, salivary, liver |

Diabetes mellitus is a metabolic disorder caused by insufficient insulin production (Type 1) or insulin resistance (Type 2), resulting in high blood sugar (hyperglycaemia). Symptoms: 1. Excessive thirst (polydipsia) 2. Frequent urination (polyuria) 3. Excessive hunger (polyphagia) 4. Weight loss despite eating more 5. Fatigue and weakness 6. Glucose in urine (glycosuria)

The hypothalamus is the link between the nervous system and the endocrine system. It: 1. Produces releasing hormones that stimulate the anterior pituitary to release its hormones 2. Produces inhibiting hormones that suppress anterior pituitary hormone release 3. Produces ADH and oxytocin, which are stored in and released from the posterior pituitary 4. Controls body temperature, hunger, thirst, and sleep-wake cycle

Adrenaline prepares the body for emergency action: 1. Increases heart rate and blood pressure 2. Dilates pupils 3. Increases breathing rate (bronchodilation) 4. Increases blood sugar (glycogenolysis in liver) 5. Diverts blood from skin and digestive system to muscles 6. Causes sweating

1. Hypothalamus: - Produces releasing and inhibiting hormones that control the pituitary - Produces ADH and oxytocin (stored in posterior pituitary) - Links the nervous system and endocrine system 2. Pituitary Gland (Master Gland): Anterior Pituitary: - GH (Growth Hormone): Growth of body — Hyper: Gigantism (child), Acromegaly (adult); Hypo: Dwarfism - TSH (Thyroid-Stimulating Hormone): Stimulates thyroid gland - ACTH (Adrenocorticotropic Hormone): Stimulates adrenal cortex - FSH (Follicle-Stimulating Hormone): Gamete production (sperm/egg) - LH (Luteinising Hormone): Ovulation, testosterone production - Prolactin: Milk production in mammary glands Posterior Pituitary: - ADH (Vasopressin): Water reabsorption in kidneys — Hypo: Diabetes insipidus - Oxytocin: Uterine contractions during childbirth, milk ejection 3. Thyroid Gland: - Thyroxine (T₄) and Triiodothyronine (T₃): Regulate basal metabolic rate (BMR), growth, development - Requires iodine for synthesis - Hyper: Graves' disease (weight loss, rapid heartbeat, bulging eyes) - Hypo in children: Cretinism (mental retardation, stunted growth) - Hypo in adults: Myxoedema (weight gain, fatigue, cold intolerance) - Iodine deficiency: Goitre (enlarged thyroid) - Calcitonin: Lowers blood calcium by promoting calcium deposition in bones 4. Parathyroid Glands: - PTH (Parathyroid Hormone): Raises blood calcium by stimulating bone resorption and calcium reabsorption in kidneys - Hypo: Tetany (muscle spasms due to low calcium) 5. Adrenal Gland: Adrenal Medulla: - Adrenaline (Epinephrine): Fight or flight hormone — increases heart rate, blood pressure, blood sugar, breathing rate - Noradrenaline (Norepinephrine): Similar effects, maintains blood pressure Adrenal Cortex: - Cortisol (Glucocorticoid): Stress response, carbohydrate metabolism, anti-inflammatory - Hyper: Cushing's syndrome (moon face, obesity) - Hypo: Addison's disease (fatigue, low BP, skin darkening) - Aldosterone (Mineralocorticoid): Na⁺ reabsorption, K⁺ secretion in kidneys 6. Pancreas: - Insulin (β-cells): Lowers blood sugar — promotes glucose uptake, glycogenesis - Hypo: Diabetes mellitus (high blood sugar, glycosuria, polyuria) - Glucagon (α-cells): Raises blood sugar — promotes glycogenolysis, gluconeogenesis 7. Pineal Gland: - Melatonin: Regulates sleep-wake cycle (circadian rhythm) 8. Thymus: - Thymosin: Promotes T-lymphocyte development (immune function)

| Feature | Nervous System | Endocrine System | |---|---|---| | Mode of signalling | Electrical impulses (neurons) | Chemical messengers (hormones) | | Speed | Very fast (milliseconds) | Slow (seconds to hours) | | Duration | Short-lasting | Long-lasting | | Pathway | Specific nerves to specific organs | Bloodstream to target organs | | Target | Specific cells/muscles/glands | Target organs with specific receptors | | Recovery | Immediate after signal stops | Gradual (hormone must be metabolised) | | Examples | Reflex action, muscle movement | Growth, metabolism, reproduction | Both systems work together: - The hypothalamus links the nervous and endocrine systems - Nervous signals can trigger hormone release (e.g., adrenaline in response to fear) - Hormones can affect neural activity (e.g., thyroxine affects brain development) - Both systems maintain homeostasis through feedback mechanisms

Feedback mechanisms regulate hormone levels to maintain homeostasis. There are two types: 1. Negative Feedback (Most Common): Negative feedback reverses a change to restore the normal level. When the level of a substance rises above normal, the body reduces its production; when it falls below normal, the body increases its production. Example 1: Thyroxine Regulation - Hypothalamus releases TRH (Thyrotropin-Releasing Hormone) - TRH stimulates anterior pituitary to release TSH - TSH stimulates thyroid to release thyroxine (T₄) - When thyroxine levels rise above normal, they inhibit TRH and TSH production - This reduces further thyroxine release → levels return to normal - When thyroxine levels fall, inhibition is removed → more TSH and thyroxine are produced Example 2: Blood Sugar Regulation - High blood sugar → Pancreas releases insulin → Blood sugar decreases - Low blood sugar → Pancreas releases glucagon → Blood sugar increases - This keeps blood sugar within the normal range (70-110 mg/dL) 2. Positive Feedback (Rare): Positive feedback amplifies a change, pushing the system further from the normal level. Example: Childbirth (Oxytocin) - Uterine contractions stimulate oxytocin release - Oxytocin causes stronger contractions - Stronger contractions stimulate more oxytocin release - This positive feedback loop continues until the baby is born - Then the loop stops (the stimulus is removed) Example: Lactation (Milk Let-Down Reflex) - Baby suckling stimulates oxytocin release from posterior pituitary - Oxytocin causes milk ejection - Continued suckling → more oxytocin → more milk