Fundamental Knowledge: Anatomy & Physiology
Part 1: Foundational Concepts
🌱 Primary Germ Layers & Differentiation
| Layer | Major Derivatives |
|---|---|
| Ectoderm | Nervous system (brain, spinal cord), epidermis (skin, hair, nails), sensory organs. |
| Mesoderm | Muscles, skeleton, cardiovascular system, excretory system, reproductive system. |
| Endoderm | Lining of digestive and respiratory tracts, liver, pancreas, thyroid. |
Systems of the Human Body
| System | Components | Main Functions |
|---|---|---|
| 🦴 Skeletal System | Bones, Cartilage, Ligaments, Joints | Provides support, protection, movement; produces blood cells; stores minerals. |
| 💪 Muscular System | Skeletal Muscles, Smooth Muscles, Cardiac Muscle | Enables body movement, maintains posture, produces heat. |
| 🧠 Nervous System | Brain, Spinal Cord, Peripheral Nerves | Receives sensory input, transmits and processes information, controls movement. |
| 🧬 Endocrine System | Pituitary Gland, Thyroid Gland, Adrenal Glands, etc. | Regulates metabolism, growth, reproduction, and mood through hormones. |
| ❤️ Cardiovascular System | Heart, Blood Vessels (Arteries, Veins, Capillaries) | Circulates blood throughout the body, transporting oxygen, nutrients, hormones. |
| 💧 Lymphatic System | Lymph Vessels, Lymph Nodes, Spleen, Thymus | Involved in immune function, protecting the body from pathogens; collects tissue fluid. |
| 🫁 Respiratory System | Nose, Pharynx, Larynx, Trachea, Bronchi, Lungs | Facilitates oxygen intake and carbon dioxide expulsion. |
| 😋 Digestive System | Mouth, Esophagus, Stomach, Small Intestine, Large Intestine | Breaks down food for nutrient absorption and eliminates waste. |
| 🚽 Urinary System | Kidneys, Ureters, Bladder, Urethra | Filters waste from blood to produce urine; regulates fluid and electrolyte balance. |
| 👶 Reproductive System | Gonads (Ovaries, Testes), Reproductive Organs | Responsible for procreation (formation of gametes, hormone secretion). |
| 🧴 Integumentary System | Skin, Hair, Nails, Sweat Glands, Sebaceous Glands | Protects the body, regulates temperature, senses stimuli. |
The Skeletal System
The Nervous System
The Circulatory System
💧 Body Fluids
| Fluid | Description |
|---|---|
| Blood | Circulates within blood vessels. Transports oxygen, nutrients, hormones, and waste products. Composed of plasma and blood cells. |
| Tissue Fluid | Fills the spaces between cells. Formed from plasma that seeps out of capillaries. Facilitates exchange of substances between blood and cells. |
| Lymph | Tissue fluid that has entered lymphatic vessels. It is returned to the blood circulation and plays a key role in the immune system. |
Part 2: Control & Regulation
🧬 Major Endocrine Glands & Hormones
| Gland | Hormone | Type | Main Function(s) |
|---|---|---|---|
| Hypothalamus | TRH, CRH, GnRH, GHRH | Peptide | Stimulate anterior pituitary |
| Somatostatin | Peptide | Inhibits GH and TSH release | |
| Dopamine | Amine | Inhibits prolactin release | |
| Pituitary (Anterior) | GH | Peptide | Growth, protein synthesis |
| TSH | Peptide | Stimulates thyroid gland | |
| ACTH | Peptide | Stimulates adrenal cortex | |
| FSH | Peptide | Follicle/Sperm development | |
| LH | Peptide | Ovulation, testosterone production | |
| Prolactin | Peptide | Milk production | |
| MSH | Peptide | Melanin synthesis | |
| Pituitary (Posterior) | ADH (Vasopressin) | Peptide | Water reabsorption in kidneys |
| Oxytocin | Peptide | Uterine contractions, milk ejection | |
| Pineal Gland | Melatonin | Amine | Circadian rhythm (sleep-wake cycle) |
| Thyroid | T3 & T4 (Thyroxine) | Amine | Increase metabolic rate |
| Calcitonin | Peptide | Lowers blood Ca²⁺ (inhibits osteoclasts) | |
| Parathyroid | PTH (Parathormone) | Peptide | Raises blood Ca²⁺ (stimulates osteoclasts) |
| Adrenal Cortex | Cortisol (Glucocorticoids) | Steroid | Stress response, gluconeogenesis |
| Aldosterone (Mineralocorticoids) | Steroid | Na⁺ reabsorption, K⁺ excretion | |
| Androgens | Steroid | Secondary sex characteristics | |
| Adrenal Medulla | Epinephrine & Norepinephrine | Amine | Fight-or-flight (SNS response) |
| Pancreas | Insulin (Beta cells) | Peptide | Lowers blood glucose |
| Glucagon (Alpha cells) | Peptide | Raises blood glucose | |
| Somatostatin (Delta cells) | Peptide | Inhibits insulin and glucagon | |
| Kidney | Erythropoietin (EPO) | Peptide | Stimulates RBC production in bone marrow |
| Renin | Enzyme/Peptide | Starts RAAS (increases blood pressure) | |
| Calcitriol | Steroid | Active Vitamin D, increases Ca²⁺ absorption | |
| Heart (Atria) | ANP | Peptide | Excretes Na⁺ and water, lowers blood pressure |
| GI Tract | Gastrin | Peptide | Stimulates HCl secretion in stomach |
| Secretin | Peptide | Stimulates bicarbonate release from pancreas | |
| CCK | Peptide | Stimulates bile and enzyme release | |
| Thymus | Thymosin | Peptide | T-lymphocyte maturation |
| Gonads (Ovaries/Testes) | Estrogen | Steroid | Female characteristics, endometrium growth |
| Progesterone | Steroid | Maintains endometrium, pregnancy | |
| Testosterone | Steroid | Male characteristics, spermatogenesis | |
| Inhibin | Peptide | Inhibits FSH secretion |
Endocrine Glands and Hormones
♀️ Menstrual Cycle Hormones
| Phase | Key Hormone(s) | Description |
|---|---|---|
| Follicular Phase | FSH, Estrogen | FSH stimulates follicle growth. Follicles produce Estrogen, which thickens the uterine lining (endometrium). |
| Ovulation | LH Surge | A surge in LH (triggered by high estrogen) causes the mature follicle to rupture and release an egg. |
| Luteal Phase | Progesterone, Estrogen | The ruptured follicle becomes the corpus luteum, which produces Progesterone and estrogen to maintain the endometrium for potential pregnancy. |
| Menstruation | Hormone Drop | If no pregnancy, the corpus luteum degrades, hormone levels drop, and the uterine lining is shed. |
Autonomic Nervous System
| Feature | Sympathetic | Parasympathetic |
|---|---|---|
| Situation | Fight or Flight | Rest and Digest |
| Heart Rate | Increase | Decrease |
| Bronchi | Dilation | Constriction |
| Digestion | Inhibition | Stimulation |
| Pupils | Dilation | Constriction |
⚡ Action Potential Phases
| Phase | Description |
|---|---|
| 1. Resting Potential | Neuron is polarized (-70mV). |
| 2. Depolarization | Na⁺ channels open, Na⁺ rushes in, potential becomes positive. |
| 3. Repolarization | Na⁺ channels close, K⁺ channels open, K⁺ rushes out. |
| 4. Hyperpolarization | K⁺ channels are slow to close, potential dips below resting. |
➡️ Neural Conduction Pathway (Reflex Arc)
| Step | Description |
|---|---|
| 1. Stimulus Reception | A sensory receptor (e.g., in the skin) detects a stimulus (e.g., heat). |
| 2. Sensory Neuron | An action potential is generated and travels along a sensory (afferent) neuron to the CNS. |
| 3. Integration Center (CNS) | In the spinal cord or brain, interneurons process the information. |
| 4. Motor Neuron | A new action potential is sent from the CNS along a motor (efferent) neuron. |
| 5. Effector Response | The motor neuron stimulates an effector (a muscle or gland) to produce a response (e.g., muscle contraction). |
Structure of a Typical Neuron
Part 3: Major Organ Systems
❤️ Cardiovascular System
Heart Structure
| Part | Function |
|---|---|
| Right Atrium | Receives deoxygenated blood from the body. |
| Right Ventricle | Pumps deoxygenated blood to the lungs. |
| Left Atrium | Receives oxygenated blood from the lungs. |
| Left Ventricle | Pumps oxygenated blood to the body. |
Blood Coagulation
| Step | Description |
|---|---|
| 1. Vascular Spasm | Damaged blood vessel constricts. |
| 2. Platelet Plug Formation | Platelets adhere to exposed collagen and form a temporary plug. |
| 3. Coagulation Cascade | Clotting factors are activated, leading to the formation of thrombin. |
| 4. Fibrin Mesh Formation | Thrombin converts fibrinogen to fibrin, which forms a stable clot. |
Structure of the Heart
🫁 Respiratory System: Lung Mechanics
| Feature | Inhalation | Exhalation |
|---|---|---|
| Muscles | Diaphragm contracts (moves down), external intercostals contract. | Diaphragm relaxes (moves up), external intercostals relax. |
| Thoracic Volume | Increases | Decreases |
| Pressure | Decreases (becomes negative relative to atmosphere) | Increases (becomes positive) |
| Air Flow | Air flows into the lungs | Air flows out of the lungs |
The Respiratory System
😋 Digestive System: Major Enzymes
| Enzyme | Source | Substrate | Product(s) |
|---|---|---|---|
| Salivary Amylase | Salivary Glands | Starch | Maltose, smaller polysaccharides |
| Pepsin | Stomach | Proteins | Smaller polypeptides |
| Pancreatic Amylase | Pancreas | Starch | Maltose |
| Trypsin | Pancreas | Proteins | Smaller polypeptides, amino acids |
| Pancreatic Lipase | Pancreas | Fats | Fatty acids, monoglycerides |
| Intestinal Enzymes | Small Intestine | Dipeptides, Disaccharides | Amino acids, monosaccharides |
The Digestive System
🚽 Urinary System: Nephron Function
| Part | Function |
|---|---|
| Glomerulus & Bowman's Capsule | Filters blood to create filtrate |
| Proximal Convoluted Tubule | Reabsorbs most water, glucose, and ions |
| Loop of Henle | Creates a salt gradient to concentrate urine |
| Distal Convoluted Tubule | Fine-tunes reabsorption of water and salts |
| Collecting Duct | Final adjustment of water reabsorption (ADH) |
Kidney Structure
Nephron Structure
Part 4: Integrated Physiology
🛡️ Immunity: Cell-mediated vs. Humoral
| Feature | Cell-mediated | Humoral |
|---|---|---|
| Primary Role | Directly destroys infected cells | Neutralizes pathogens in body fluids |
| Key Cells | T-Cells (Helper T, Killer T) | B-Cells (differentiate into Plasma Cells) |
| Target | Virus-infected cells, cancer cells | Bacteria, viruses, toxins (extracellular) |
| Mechanism | Killer T-cells directly attack | Antibodies bind to pathogens |
Antigen-Antibody Reaction
💪 Muscle Contraction
Sliding Filament Steps
| Step | Description |
|---|---|
| 1. Nerve Signal | Acetylcholine is released at the neuromuscular junction. |
| 2. Excitation | Action potential travels down T-tubules. |
| 3. Calcium Release | Sarcoplasmic reticulum releases Ca²⁺. |
| 4. Binding | Ca²⁺ binds to troponin, moving tropomyosin off actin binding sites. |
| 5. Power Stroke | Myosin heads, powered by ATP, bind to actin and pull, shortening the sarcomere. |
Contraction Types
| Type | Description |
|---|---|
| Isotonic (Concentric) | Muscle shortens while generating force (e.g., lifting a weight). |
| Isotonic (Eccentric) | Muscle lengthens while generating force (e.g., lowering a weight slowly). |
| Isometric | Muscle generates force without changing length (e.g., pushing against a wall). |
Sarcomere Contraction
👁️ Sensory System
Vision: Photoreceptors
| Feature | Rods | Cones |
|---|---|---|
| Function | Night vision (high sensitivity) | Color vision (low sensitivity) |
| Location | Peripheral retina | Central retina (fovea) |
| Visual Pigment | Rhodopsin | Photopsins (3 types) |
Adaptation
| Feature | Light Adaptation | Dark Adaptation |
|---|---|---|
| Process | From Dark to Light | From Light to Dark |
| Time | Fast (minutes) | Slow (20-30 minutes) |
| Key Photoreceptor | Cones take over | Rods take over |
| Mechanism | Rhodopsin breaks down (bleaching) | Rhodopsin regenerates |
Structure of the Eye
Structure of the Ear
🩸 Diabetes Mellitus
| Feature | Type 1 | Type 2 |
|---|---|---|
| Cause | Autoimmune destruction of pancreatic β-cells | Insulin resistance and/or deficiency |
| Insulin Production | Absolute deficiency | Relative deficiency or ineffective action |
| Typical Onset | Childhood/Young Adulthood | Adulthood (increasingly younger) |
| Treatment | Insulin injections required | Diet, exercise, oral medication, sometimes insulin |
Theme 33: The Circulatory System
#33
Name the four chambers of the human heart and describe the path of blood through the systemic circulation and the pulmonary circulation, using these chambers and the major blood vessels (aorta, vena cava, pulmonary artery, pulmonary vein).
Theme 34: The Respiratory System
#34
Explain the mechanism of gas exchange in the lungs, focusing on the structure of the 'alveoli' and 'capillaries,' and the difference in the partial pressures of oxygen and carbon dioxide.
Theme 35: The Digestive System
#35
For the three major nutrients—proteins, carbohydrates (starch), and lipids—describe in which digestive organs, by which digestive enzymes, and into what final substances they are broken down to be absorbed.
Theme 36: The Urinary System
#36
Describe the process of urine formation in the kidneys, dividing it into the three steps of 'glomerular filtration,' 'tubular reabsorption,' and 'tubular secretion.'
Theme 37: Neuron and Synaptic Transmission
#37
Describe the mechanism of action potential generation and conduction in a neuron. Also, describe the process of chemical transmission at a synapse.
Theme 38: Blood Glucose Regulation
#38
Name the two main hormones involved in the regulation of blood glucose levels, and for each, state from which endocrine gland it is secreted and what effect it has on blood glucose levels.
Theme 39: Innate and Adaptive Immunity
#39
Compare and contrast 'innate immunity' and 'adaptive immunity' from the three perspectives of speed of response, specificity, and the presence of memory.
Theme 40: B cells and T cells
#40
Describe the main roles of B cells and T cells, the lymphocytes central to adaptive immunity, and the type of immunity each leads (humoral and cell-mediated).
Theme 41: Central and Peripheral Nervous System
#41
The nervous system is divided into the central and peripheral nervous systems. Name the components of each and explain their functional differences. Also, state how the peripheral nervous system is further functionally classified.
Theme 42: Body Temperature Regulation
#42
Explain how human body temperature is regulated in cold and hot environments, from the perspectives of heat production and heat loss, with the hypothalamus as the control center.
Theme 43: Water and Salt Balance
#43
Explain how the osmotic pressure and circulating blood volume of body fluids are regulated, focusing on the roles of 'antidiuretic hormone (ADH)' and 'aldosterone.'
Theme 44: Carbohydrates and Lipids
#44
For carbohydrates and lipids, name their basic constituent units and the main storage form in animals. Also, state the difference between the two from the perspective of energy efficiency.
Theme 45: Muscle Contraction
#45
Explain the mechanism of skeletal muscle contraction (the sliding filament theory), describing the roles of actin filaments, myosin filaments, calcium ions (Ca²⁺), and ATP.
Theme 46: The Eye
#46
Describe the pathway by which light entering the eye forms an image on the retina and is transmitted to the brain. Also, state the functional differences between the two types of photoreceptor cells (rods and cones).
Theme 47: The Ear
#47
Describe the mechanism by which the ear perceives sound (hearing) and the body's sense of balance (equilibrium), naming the main parts involved.
Theme 48: Reproduction and Development
#48
Describe the main differences between oogenesis (egg formation) and spermatogenesis (sperm formation) in humans, focusing on the timing of cell division and the number of final cells produced.
Theme 49: The Skeletal System
#49
List four main functions of the skeletal system. Also, explain how bone is a dynamic tissue that is constantly being remodeled, focusing on the roles of 'osteoblasts' and 'osteoclasts.'
Theme 50: Enzymes
#50
Explain the mechanism by which enzymes function as catalysts, using the terms 'active site' and 'activation energy.' Also, name two major factors that affect the reaction rate of enzymes.
Theme 51: The Integumentary System
#51
Describe the main functions of the skin. Also, name the two main layers of the skin and the primary tissue type of each.
Theme 52: The Lymphatic System
#52
Describe the three main functions of the lymphatic system.
Theme 53: Thyroid and Adrenal Glands
#53
Name the primary hormones produced by the thyroid gland and the adrenal cortex, and state one major function for each.
Theme 54: The Female Reproductive System
#54
Describe the events of the ovarian cycle and the uterine (menstrual) cycle, and name the key hormones that regulate them.
Theme 55: The Male Reproductive System
#55
Trace the path of sperm from its site of production to its exit from the body during ejaculation.
Theme 56: Muscle Tissue Types
#56
Compare the three types of muscle tissue (skeletal, cardiac, and smooth) in terms of their structure (striations, number of nuclei), control (voluntary or involuntary), and a typical location in the body.
Theme 57: Joints and Articulations
#57
Describe the three major structural classifications of joints. Which of these types allows for the greatest range of motion?
Theme 58: Blood Typing
#58
Explain the basis of the ABO blood group system, referring to the antigens on red blood cells and the antibodies in the plasma for each blood type (A, B, AB, O).
Theme 59: The Reflex Arc
#59
Describe the five essential components of a simple reflex arc in the correct order.
Theme 60: Taste and Smell
#60
Explain how chemical stimuli are transduced into neural signals for the senses of taste (gustation) and smell (olfaction).
Theme 61: Hormone Classification & Action
#61
Broadly classify hormones based on their chemical structure into two main types. For each type, explain where its receptor is located and its general mechanism of action.
Theme 62: The Hypothalamus-Pituitary Axis
#62
Describe the relationship between the hypothalamus and the anterior pituitary, and the relationship between the hypothalamus and the posterior pituitary, explaining how the hypothalamus controls each part.
Theme 63: Growth Hormone
#63
From which gland is Growth Hormone (GH) secreted? Describe its main functions and the conditions that result from its hypersecretion or hyposecretion during childhood.
Theme 64: Feedback Regulation
#64
Explain the concept of 'negative feedback' in the endocrine system using the regulation of thyroid hormones as an example. Mention the roles of the hypothalamus, pituitary gland, and thyroid gland.