Comprehensive Notes on Body Systems, Disorders, and Basic Pharmacology
Introduction to Anatomical Concepts and Organization
Anatomy: Refers to the physical structures in the body, such as bones, organs, and cells, and the relationships between these structures.
Physiology: Refers to the functions of the body structures.
Pathophysiology: Refers to any change, disease, or injury that influences the normal functioning of body systems.
Tissue: A group of cells with similar structures that perform a specific function.
Histology: The field of study involving the microscopic examination of tissue appearance, organization, and function.
Levels of Organization: The body is structured from atoms and molecules up to cells, tissues, organs, organ systems, and finally the organism level.
Organ System: A group of organs working together to perform major functions (e.g., digestive, respiratory).
Directional Anatomical Terms:
Anterior (Ventral): The front of the body (e.g., toes are anterior to the foot).
Posterior (Dorsal): The back of the body.
Superior (Cranial): A position above or higher.
Inferior (Caudal): A position below or lower; near the coccyx (tail).
Lateral: Toward the side of the body.
Medial: Toward the middle of the body.
Proximal: Nearer to the point of attachment or trunk.
Distal: Farther from the point of attachment or trunk.
Superficial: Closer to the body surface.
Deep: Farther from the body surface.
Body Planes:
Sagittal Plane: Divides the organ/body vertically into right and left sides. Midsagittal (Median) is directly down the middle; Parasagittal divides into unequal sides.
Frontal (Coronal) Plane: Divides the body into anterior (front) and posterior (rear) portions.
Transverse (Horizontal) Plane: Divides the body horizontally into upper and lower portions, producing cross-sections.
Body Cavities:
Dorsal (Posterior) Cavity: Contains the brain and spinal cord.
Ventral (Anterior) Cavity: Contains the lungs, heart, stomach, and intestines. This cavity allows organs to expand and contract (e.g., during respiration or digestion).
The Dental and Oral System (KT0101)
Oral Cavity (Mouth): Prepared food via mastication (chewing) and pre-digestion using salivary enzymes. It also aids speech production.
Teeth Structure:
Sections: Crown (above gum line), Neck, and Root (below gum line).
Layers: Enamel (very hard outer covering), Dentin (hard tissue making up most of the tooth), Pulp (soft center with blood vessels and nerves), and Cementum (covers the root).
Ligaments: Periodontal ligaments connect roots to the bone and gum.
Types of Teeth: Incisors (front), Canines (eye teeth), Bicuspids (premolars), and Molars (back).
Gums (Gingiva): Soft mucous membranes that form a tight seal around the teeth to provide a bacterial barrier.
Salivary Glands: Three pairs release saliva through ducts to moisten food and begin chemical digestion.
Parotid: Below/front of ears; produces solution with water and ptyalin to digest carbohydrates.
Submandibular: Near the base of the tongue.
Sublingual: Under the tongue.
Tongue: Muscle organ covered in papillae that house taste buds (chemoreceptors). It aids in gripping, moving food, and swallowing (a process that begins voluntarily then becomes an involuntary reflex).
Dental Care: Key practices include flossing once a day, brushing after meals with fluoride toothpaste, and avoiding sugar. Sugar permits plaque growth.
Common Dental Conditions:
Halitosis (Bad Breath): Causes include Intraoral (gingivitis, tongue coating, cavities, food debris, xerostomia) and Extraoral (liver failure, diabetes, sinusitis, lung disease, GORD).
Xerostomia (Dry Mouth): Insufficient saliva flow caused by dehydration, medication (antihistamines, antidepressants), or radiotherapy. Increases risk of thrush and cavities.
Plaque and Calculus: Plaque is a bacterial film that produces acid. Left unchecked, it mineralizes into hard Calculus (Tartar) which requires professional removal.
Dental Abscess: Pocket of pus causing severe throbbing pain; treated with antibiotics.
Oral Candidiasis (Thrush): Candida albicans overgrowth (white patches). Often seen in infants. Treatment: Nystatin suspension (), 1 mL 6-hourly for 7 days.
Gingivitis: Inflammation of gum edges. Treatment: Chlorhexidine 0.2% mouthwash twice daily for 5 days.
Periodontitis: Plaque builds up and spreads to bone, causing loosening of teeth.
Herpes Simplex (Cold Sores): Painful blisters on lips/nose. Treatment: Topical acyclovir ointment 5 times daily.
Aphthous Ulcers (Mouth Ulcers): Shallow holes in lining caused by trauma, stress, or allergens. Major ulcers (>1\,\text{cm}) may indicate advanced HIV.
Infant Teething: Normal process causing fretfulness and drooling. Not a cause of diarrhea or high fever.
The Gastro-intestinal (GI) Tract and Digestive System
GI Tract Path: Oral cavity -> Pharynx -> Oesophagus -> Stomach -> Small Intestine -> Large Intestine -> Rectum -> Anus.
Digestive Processes: Ingestion, Digestion, Motility (peristalsis), Secretion (enzymes/bile), Absorption, Defense (mucosal immunity), and Elimination (defecation).
Organs and Functions:
Pharynx: Cone-shaped passage for both air and food.
Oesophagus: Muscular tube ( long). Joins the stomach at the cardiac sphincter.
Stomach: J-shaped storage area (holds approx ). Churns food into chyme. Gastric glands contain Parietal cells (produce HCl and intrinsic factor) and Chief cells (produce lipase and pepsinogen). Pepsinogen is converted to pepsin by acid to break down protein.
Small Intestine: Approx long. Consists of Duodenum (; absorbs iron, magnesium), Jejunum (; absorbs most nutrients), and Ileum (; absorbs Vitamin with intrinsic factor).
Villi/Microvilli: Finger-like projections in the small intestine that increase surface area for absorption.
Large Intestine (Colon): long. Absorbs water, eliminates salts, and houses flora that produce Vitamin K. Includes the Caecum (with the appendix), Colon (ascending, transverse, descending, sigmoid), and Rectum.
Accessory Organs:
Liver: Produces bile, detoxifies blood, stores iron/vitamins (), and performs gluconeogenesis.
Gallbladder: Stores and concentrates bile. Bile emulsifies fats.
Pancreas: Dual function. Exocrine: secretes juice rich in bicarbonate, amylase (carbs), trypsin (protein), and lipase (fats). Endocrine: produces insulin and glucagon.
Disorders of the Digestive System
Anal Fissures: Small cracks in the anal margin; treated with stool softeners like Lactulose.
Appendicitis: Inflammation of the appendix. Clinical emergency. Symptoms: Pain migrating to the right leg, fever, bloated abdomen. Requires surgical appendectomy.
Cholera: Notifiable condition causing "rice water" watery diarrhea and rapid dehydration. Caused by Vibrio cholera. Prevention: Hygiene and water chlorination. Treatment: Rehydration and Ciprofloxacin ( 12-hourly for 3 days for adults; for children).
Constipation: Change in habit resulting in hard stools. Prevention: High-fiber diet and hydration ( glasses of water).
Diarrhoea: Sudden onset of liquid stools. Danger signs: Convulsions, altered consciousness, intractable vomiting. Referral required for adults after 3 days, children under 3 after 2 days. Rehydrate solution recipe: 1L water + 8 tsp sugar + 1 tsp salt (adult dose).
Dysentery: Bloody/mucoid diarrhea usually caused by bacteria like Shigella.
GORD (Gastro-oesophageal Reflux Disease): Persistent acid reflux causing heartburn. Treatment: Lansoprazole ( daily) for max 14 days.
Haemorrhoids (Piles): Varicose veins of the anorectal area caused by straining/lack of fiber. Treated with Bismuth subgallate ointment/suppositories.
Helminthic Infestations (Worms):
Tapeworm: Segmented; reached by raw beef/pork. Treatment: Albendazole.
Roundworm (Ascaris lumbricoides): Most common world-wide. Larvae travel to lungs, are coughed up and swallowed.
Hookworm: Penetrates barefoot skin. Causes anemia.
Pinworm: Common in children; causes nocturnal anal itching. Treatment: Mebendazole ( single dose for adults).
IBS (Irritable Bowel Syndrome): Functional disorder of motility. Symptoms: Bloating, borborygmi, bowel habit variations. Treatment: Symptomatic (fiber for constipation, anti-propulsives for diarrhea).
Peptic Ulcers: Lesions in stomach or duodenum caused by HCl/Pepsin, Helicobacter pylori, or NSAIDs. Treatment for H. pylori: Amoxicillin + Metronidazole + PPI for days.
The Endocrine System (KT0103)
Mechanism: Functions via chemical messengers called Hormones that travel through blood to target cells. Uses a Lock and Key receptor system.
Negative Feedback Loop: The body regulates hormone levels similarly to a thermostat. Output is fed back to reduce fluctuations.
Major Glands and Hormones:
Adrenal Glands: Consist of Cortex (Glucocorticoids/Cortisol for stress; Mineralocorticoids/Aldosterone for salt balance; Androgens) and Medulla (Adrenaline/Noradrenaline for "Fight or Flight").
Cushing’s Syndrome: Excess cortisol causing "moon face" and "buffalo hump."
Pancreas: Beta cells produce insulin (lowers blood glucose); Alpha cells produce glucagon (raises blood glucose). Somatostatin inhibits both.
Pineal Gland: Small pinecone-shaped organ; produces Melatonin to regulate Circadian Rhythms (sleep cycle).
Pituitary Gland (Master Gland): Controlled by the Hypothalamus. Produces Growth Hormone (GH), TSH, ACTH, FSH/LH, Prolactin, ADH, and Oxytocin.
Thymus: Lymphoid organ producing T-lymphocytes (T-cells). Shrinks and turns to fatty tissue after puberty.
Thyroid: Butterfly-shaped. Produces Triiodothyronine (T3) and Thyroxine (T4). Requires Iodine for synthesis. Functions: metabolism, heart rate, brain development.
Parathyroid Glands: Four pea-sized glands; produce PTH to regulate blood calcium by pulling it from bones.
Thyroid Conditions:
Hypothyroidism: Slow metabolism. Caused by Hashimoto's disease. Treatment: Levothyroxine ( daily).
Hyperthyroidism: Rapid metabolism. Caused by Grave's disease. Results in weight loss, heat intolerance, tremor.
Diabetes Mellitus
Type 1: Juvenile-onset; Immune system destroys insulin-producing beta cells. Requires lifelong insulin injections. Risk: Diabetic Ketoacidosis (fruity breath, confusion).
Type 2: Adult-onset; Insulin resistance or insufficient production. Linked to obesity and inactivity.
Prediabetes: Blood sugar elevated but not at diagnostic range; reversible with lifestyle change.
Gestational Diabetes: Diagnosed during pregnancy; may lead to high birth weight babies.
Diagnostic Thresholds:
Random blood glucose
Fasting blood glucose
HbA1c test gives average glucose over months ( is ideal).
Complications: Neuropathy (nerve damage), Nephropathy (kidney damage), Foot ulcers, and Cardivascular risks.
Dietary Guidance: Abdominal obesity is waist circumference >94\,\text{cm} (men) and >80\,\text{cm} (women). . Cut salt to < \frac{1}{2} tsp/day.
Concepts of Nutrition and Essential Nutrients
WHO Five Keys to Healthy Diet: 1. Breastfeed babies (exclusively for 6 months, up to 2 years+). 2. Eat a variety of unprocessed foods. 3. Plenty of vegetables/fruit (5 servings/day). 4. Limit fats/oils (avoid trans-fats). 5. Limit salt/sugars.
Macronutrients: Protein (building blocks), Carbohydrates (brain fuel), Fat (energy/absorbs vitamins), Water.
Micronutrients (Fat-Soluble Vitamins):
Vitamin A (Retinol): For vision and immune function. Night blindness is a deficiency sign. High intake (>3300\,\text{mcg}) in pregnancy is teratogenic.
Vitamin D (Cholecalciferol): "Sunshine vitamin." Absorbs calcium. Deficiency causes Rickets in children.
Vitamin E (Alpha-tocopherol): Antioxidant; protects cell membranes.
Vitamin K (Phytonadione): Regulates blood clotting.
Micronutrients (Water-Soluble Vitamins):
B1 (Thiamine): Deficiency causes Beriberi or Wernicke-Korsakoff syndrome (common in alcohol abuse).
B2 (Riboflavin): Supports cell growth. Deactivated by light. High intake causes yellow urine.
B3 (Niacin): Deficiency causes Pellagra (characterised by the 3 D's: Diarrhea, Dementia, Dermatitis).
B9 (Folic Acid): Critical in pregnancy to prevent Spina Bifida.
B12 (Cyanocobalamin): Only in animal products. Requires Intrinsic Factor for absorption. Shortage causes Megaloblastic Anaemia.
Vitamin C (Ascorbic Acid): Building block for collagen. Antioxidant. Deficiency causes Scurvy (bleeding gums).
Essential Minerals:
Calcium: Bone health, blood clotting, heart rhythm.
Magnesium: Electrical conductor for heart/muscle contraction.
Potassium: Deficiency (Hypokalaemia) causes tremors/constipation. Excess (Hyperkalaemia) can cause cardiac arrest.
Iron: Component of haemoglobin. Tea/milk inhibit absorption. Deficiency causes most common world-wide anemia.
Iodine: Required for thyroid function. Deficiency causes Cretinism (permanent mental retardation).
Zinc: Role in wound healing, immune system, taste/smell.
Malnutrition Diseases:
Marasmus: Lack of protein and calories; results in emaciation/wrinkled skin.
Kwashiorkor: Lack of protein only; sign is edema (swelling), "pot belly," and reddish hair.
The Cardiovascular System (KT0105)
The Heart: Strikes nearly times a day. Pumps of blood/min at rest ().
Heart Wall Layers: Pericardium (outer/lubricating), Epicardium, Myocardium (middle muscular layer; generates the pump), Endocardium (inner lining; prevents clots).
Heart Chambers: Right Atrium (receives deoxygenated blood from Vena Cava) -> Right Ventricle (pumps to lungs via Pulmonic valve) -> Left Atrium (receives oxygenated blood from pulmonary vein) -> Left Ventricle (thicker wall; pumps to body via Aorta).
Valves: Tricuspid (right), Mitral/Bicuspid (left), Pulmonic, Aortic. Ensure one-way flow.
The Heartbeat: Initiated at the Sinus Node (pacemaker). "Lubb-dupp" sound is valve closure (Mitral/Tricuspid then Aortic/Pulmonic).
Vessels: Arteries (carry blood from heart), Arterioles (small terminal branches), Capillaries (one-cell-thick exchange site), Venules, and Veins (carry blood to heart; have valves).
Blood Pressure (BP): Force against artery walls. Systolic (contraction) over Diastolic (relaxation).
Normal: .
Hypertension Stages: Pre (), Stage 1 (), Stage 2 (), Stage 3/Malignant (>180/>110).
Cardiovascular Conditions:
Angina Pectoris: Chest pain (<15\,\text{min}) from ischemia. Treatment: Nitrates (sensitive to light) and Aspirin ( daily).
Atherosclerosis: Accumulation of plaque (fat, cholesterol, calcium) narrowing blood vessels.
Congestive Cardiac Failure (CCF): Heart cannot pump effectively. Sign is peripheral edema (ankle swelling with pitting).
Hypercholesterolaemia: Elevation of cholesterol. Statins (e.g., simvastatin) are used for treatment.
Myocardial Infarction (MI): Complete occlusion of coronary artery. Crushing pain for >20\,\text{min}. Medical emergency.
Rheumatic Fever: Notifiable. Follows streptococcal throat infection. Affects heart and joints.
Blood and Immune System
Composition: on average ( of body weight). Consists of Plasma ( water, proteins like albumin/fibrinogen) and Formed Elements (Cells).
Blood Cells:
Erythrocytes (RBC): Contain haemoglobin/iron. Lifespan days.
Leucocytes (WBC): Defense cells. Granulocytes (Neutrophils, Eosinophils, Basophils) and Agranulocytes (Lymphocytes, Monocytes).
Thrombocytes (Platelets): Lifespan days. Essential for coagulation (turning fibrinogen into fibrin).
Blood Groups: Based on Antigens (on cells) and Antibodies (in plasma).
Type O: Universal donor (no A/B antigens).
Type AB: Universal recipient (no anti-A/B antibodies).
Rhesus (Rh) System: Rh+ (antigen present) vs Rh-.
Immune Mechanisms:
Innate (Non-Specific): Immediate defense. Physical barriers (skin), mechanical (cilia/cough), biochemical (HCl in stomach, Lysozyme in tears), and cellular (Phagocytes, Natural Killer cells).
Adaptive (Specific): Acquired. B-cells (produce antibodies) and T-cells (cellular immunity). Features: recognition, specificity, and memory.
Passive Immunity: Transfer of antibodies (mother to child via placenta/breastmilk; artificial via snake bite antivenom).
Active Immunity: Induced by infection or vaccination.
Immunization: Community (Herd) Immunity requires specific thresholds (e.g., Measles , Polio ).
Childhood Immunization Schedule (EPI-SA): Covers 11 diseases including Polio, Tetanus, Hepatitis B, Measles, TB (BCG vaccine given at birth), Hib, and Rotavirus.
Immune Disorders:
Autoimmune: Body attacks itself (e.g., Type 1 Diabetes, Rheumatoid Arthritis, Lupus).
Allergies: Hypersensitivity reactions involving Mast cells and Histamine. Anaphylaxis is a life-threatening emergency (drop in BP, airway closure).
The Integumentary System (Skin)
Functions: Protection (pH ), Heat regulation (vasodilation/vasoconstriction, sweating), Excretion, and Sensation.
Anatomy:
Epidermis: Outer layer (5 sub-layers). Stratum corneum (surface scaly cells filled with keratin) sloughs off every days.
Dermis: Connective tissue with collagen/elastic fibers. Contains blood vessels, glands, and sensors.
Hypodermis (Subcutis): Adipose/Fat layer. Insulates and cushions.
Accessory Organs: Hair (shaft/root), Nails (grow ), and Glands (Eccrine sweat glands all over; Apocrine sweat glands in armpits/groin; Sebaceous oil glands).
Skin Diseases:
Burns: 1st Degree (epidermis), 2nd Degree (dermis), 3rd Degree (full depth; requires skin graft).
Acne Vulgaris: Inflammation of hair follicle; caused by sebum plugging and P. acnes bacteria.
Infections: Cellulitis (spreading tissue infection), Impetigo (honey-coloured crusts on face), Tinea Pedis (Athlete's foot), Scabies (itch mites burrowing under skin).
Conditions: Atopic Eczema (chronic itchy rash), Psoriasis (silvery scaly plaques), Shingles (Herpes zoster; painful vesicles along nerve path), Albinism (absence of pigment), Vitiligo (depigmentation patches).
Reproductive, Renal, and Nervous Systems
Reproductive System:
Female: Ovaries produce Oestrogen and Progesterone. Menstrual cycle ( days) involves ovulation triggered by LH surge. Menopause occurs after 12 months without a period.
Male: Testes produce Testosterone and Sperm. Conditions include Hypogonadism, Impotence, and BPH (Benign Prostatic Hyperplasia; causes urinary hesitancy).
STIs/STDs: Chlamydia (the "silent" disease), Genital Herpes (HSV-2), Gonorrhoea, Syphilis (Stage 1 Chancre; Stage 2 Rash; Stage 3 Tertiary effects), Hepatitis (A, B, C).
HIV/AIDS: Virus attacks CD4 Helper cells. Stages: 1. Asymptomatic, 2. Moderate weight loss, 3. Severe weight loss/Opportunistic infections (persistent thrush/TB), 4. AIDS/Wasting.
Renal System:
Function: "A WET BED" (Acid-base, Water balance, Electrolytes, Toxins, BP, Erythropoietin, D-vitamin activation).
Nephron: Functional unit with Glomerulus and Bowman's capsule. Bladder holds approx (urge felt at ).
Conditions: CKD (Chronic Kidney Disease Stages 1–5), Haematuria (blood in urine), Renal Calculi (kidney stones), UTI (mostly caused by E. coli).
Nervous System:
CNS: Brain and Spinal Cord. Protective layers are the Meninges (Dura, Arachnoid, Pia). CSF acts as a physical buffer.
PNS: Somatic (skeletal) and Autonomic (Sympathetic "Fight/Flight" vs Parasympathetic "Rest/Digest").
Neurons: Transmit signals via neurotransmitters (Excitatory like Adrenaline; Inhibitory like GABA).
Mental Health Disorders: Anxiety, Bipolar, Depression (risk factor for suicide), Schizophrenia (positive, negative, and cognitive symptoms).
Neurological Conditions: Epilepsy (recurrent seizures), Meningitis (infection of lining; viral, bacterial, fungal), Stroke (Ischaemic block vs Haemorrhagic burst).
Basic Pharmacology (KT02)
Pharmacodynamics (PD): Relationship between drug concentration and effect. Action via Mechanism of Action (MOA) on Receptors.
Agonist: Activates receptor.
Antagonist: Blocks receptor.
Therapeutic Index: Ratio of MTD to MED. Low index = narrow safety threshold (e.g., Warfarin, Digoxin).
Pharmacokinetics (PK): ADME (Absorption, Distribution, Metabolism, Excretion).
Bioavailability: Fraction of drug reaching blood. IV route = .
First-Pass Effect: Concentration reduction in liver/gut before reaching blood.
Half-life (): Time to eliminate half the blood level. Usually eliminated after 5 half-lives.
Metabolism: Mostly in liver via Cytochrome P450 enzymes. Inhibited by Grapefruit juice.
Toxicology: Study of adverse effects. Paracetamol maximum daily dose is ; overdose causes liver damage.
Pharmacovigilance: Science of detecting and preventing ADRs (Adverse Drug Reactions). Reported to SAHPRA and NADEMC.
Package Inserts (PI) vs PIL: PI is technical for professionals. Patient Information Leaflet (PIL) is simplified for a grade 10 reading level and must be provided at dispensing.
Classification Systems:
ICD10: Diagnostic codes for medical conditions (e.g., E11 for Type 2 Diabetes).
ATC Classification: Anatomical Therapeutic Chemical index. 5 levels: 1. System, 2. Therapeutic, 3. Pharmacological, 4. Chemical, 5. Substance (e.g., C03CA01 for furosemide).