Human Physiology for Medical School & Faculty of Medicine

Study the normal functions of living tissues and organs, disease mechanisms, and prevention and treatment across specialties, including metabolism, respiration, growth, and regulation.

Explore the cell as the fundamental unit of life, detailing prokaryotic and eukaryotic types and organelles such as nucleus, DNA, ribosomes, mitochondria, cytoplasm, and the cell membrane.

Explore the four primary tissues—epithelial, connective, muscle, and nervous—and their roles in covering, supporting, moving, and signaling throughout the body.

Discover how body organs arise from multiple tissues, classify as hollow or parenchymal, and learn about key organs like the heart, lungs, brain, liver, kidneys, stomach, and intestines.

Organ systems coordinate to carry out functions such as digestion, excretion, cardiovascular and respiratory transport, reproduction, endocrine growth and regulation, musculoskeletal stability, and nervous control of locomotion and intellectual functions.

Explore the cell structure, focusing on the cell membrane, cytoplasm, and nucleus, and trace membrane models from the Danielli Davison to the fluid mosaic model.

The lipid bilayer is a membrane of phospholipids and cholesterol, with hydrophilic heads outward and hydrophobic tails inward, studded with glycoproteins and integral and peripheral proteins, semipermeable to fat-soluble molecules.

Protein layers coat both surfaces of the central lipid layer, containing glycoproteins and distinguishing integral (transmembrane) and peripheral proteins that enable transport, receptors, enzymes, and adhesion.

Explore how carbohydrates attach to proteins and lipids to form glycoproteins, proteoglycans, and glycolipids, building the glycocalyx. See how the glycocalyx and carbohydrate charge enable selective permeability and hormone receptors.

Synthesize proteins and glycoproteins in rough ER for secretion, while smooth ER makes lipids, detoxifies substances, and stores calcium within the cytoplasm's ectoplasm and endoplasm.

Processes proteins and lipids in most cells, except red blood cells. Functions as the cell’s post office with cis and trans faces near the endoplasmic reticulum.

Lysosomes are membrane-bound vesicles formed by the Golgi apparatus that house hydrolytic enzymes. They participate in heterophagy and autophagy, activate in acidic pH, digest macromolecules, and enable exocytosis of waste.

Peroxisomes form from the endoplasmic reticulum and house catalase, urate oxidase, and d-amino acid oxidase to drive beta-oxidation, detoxify hydrogen peroxide, and support liver metabolism and bile acid formation.

Produce energy through the mitochondrial respiratory chain and oxidative phosphorylation to synthesize ATP. Move in cytoplasm, contain DNA, store calcium, and participate in apoptosis via cytochrome c and Smac Diablo.

Ribosomes, membrane-less organelles, synthesize proteins using ribosomal RNA and messenger RNA, attaching to rough endoplasmic reticulum or acting freely in the cytoplasm.

Explore the nucleus, the largest cellular organelle in eukaryotic cells, housing chromatin, nucleoplasm, and nucleolus, and driving gene storage, RNA synthesis, ribosome assembly, and cell division.

Examine DNA structure, the double helix with base pairing, and how genes encode proteins via codons; cover genome, transcription, translation, and genetic disorders (single-gene, chromosomal, mitochondrial).

Learn how RNA structures function in protein synthesis, detailing mRNA, tRNA, and rRNA roles, transcription by RNA polymerase, and translation at the ribosome.

Promote proliferation, differentiation, and maturation as signaling proteins that bind receptors; growth factors are distinct from cytokines, with examples like PDGF, NGF, EGF, IGF, and TGF guiding formation of vessels.

Explore necrosis, an uncontrolled cell death caused by external damage, and its inflammatory tissue response, including edema, leukocyte migration, calcium release, and wound healing.

Explore how cells undergo atrophy and hypertrophy, including physiological and pathological forms, compensatory changes, hyperplasia, dysplasia, and metaplasia with examples.

Explore how cytoplasmic cell degeneration damages tissues while the nucleus remains intact, with aging diminishing function; examine stem cells' self-renewal and pluripotency for tissue repair and therapeutic uses.

Explore tight junctions and other cell junctions, including occluding, barrier, and fencing roles that govern tissue strength, polarity, and the blood brain barrier's selective diffusion.

Gap junctions, also called nexus, form intercellular channels that allow direct passage of ions, glucose, amino acids, and other small molecules between adjacent cells, regulated by calcium, pH, and connexins.

Anchoring junctions provide mechanical strength by linking cells or to the extracellular matrix through actin or intermediate filaments, via adherens junctions, desmosomes, focal adhesions, and hemidesmosomes, involving cadherins and integrins.

Explore how the cell membrane enables transport of nutrients, water, and wastes via passive and active mechanisms. Distinguish diffusion through lipid or protein layers and carrier-mediated diffusion via channels.

Study gated protein channels that open on demand, including voltage, ligand, and mechanically gated types. See action potentials driving ion flux in neuromuscular junctions and key sensory structures.

Explore passive transport beyond diffusion, including bulk flow, filtration, and osmosis, with examples from the respiratory membrane and kidney glomeruli, and clarify osmotic pressure and reverse osmosis.

Active transport moves substances against gradients using ATP. Carrier proteins enable primary and secondary active transport via uniport, symport, and antiport, moving ions like sodium and potassium.

Primary active transport uses ATP energy via the Na+/K+ ATPase pump to move 3 Na+ out and 2 K+ in, maintaining the resting membrane potential.

Explore secondary active transport, where sodium co-transport moves glucose and amino acids via symport, while counter transport exchanges ions like sodium with calcium, hydrogen, or others across membranes.

Explore vesicular transport, including endocytosis, exocytosis, and transcytosis, focusing on pinocytosis, phagocytosis, and receptor mediated endocytosis via clathrin or caveolin pits that form endosomes and lysosomes.

Exocytosis expels substances from the cell via secretory vesicle fusion with the membrane, often with calcium ions, while transcytosis transports extracellular macromolecules across cells via caveolin-coated pits.

Explore molecular motors kinesin, dynein, and myosin, their ATP-driven transport on microtubules and microfilaments, kinesin anterograde, dynein retrograde, and Na+ K+ pump abnormalities linked to cardiac failure and hypertension.

Explore how homeostasis keeps the body's milieu intérieur in balance, with extracellular fluid constantly moving and supplying nutrients and ions, essential for health.

Explore how the body maintains balance through systems coordinating pH, temperature, nutrients, and fluids. Learn how the respiratory system, kidneys, digestion, blood, and the nervous system regulate homeostasis.

Sensors detect deviations, the control center coordinates responses, and effectors restore balance via nerves or hormones; negative feedback normalizes, while positive feedback amplifies changes.

Stabilize the body's balance by triggering negative feedback when conditions deviate. Guide homeostasis through thyroid hormone signaling: excess thyroxine lowers TSH in the pituitary, while deficiency ramps up production.

explore how positive feedback acts as a chain reaction that amplifies changes in the same direction, with examples like blood clotting and oxytocin-driven childbirth and milk ejection.

Learn how acid base balance sustains body homeostasis, using Henderson-Hasselbalch to assess status, maintain extracellular pH near 7.4, and prevent acidosis or alkalosis.

Determine acid-base status with the Henderson-Hasselbalch equation using bicarbonate and CO2 (pKa 6.1) and plasma pH, linking CO2 and HCO3 balance to acidosis or alkalosis and buffering and renal mechanisms.

Explore how the phosphate buffer system safeguards pH balance in cells and kidneys, using sodium dihydrogen phosphate and disodium hydrogen phosphate, and outperforms bicarbonate buffers.

explore how protein buffers in plasma keep blood pH balanced using histidine and lysine. outperforms plasma proteins, especially when deoxygenated, hemoglobin helps maintain pH stability with every breath.

Explore how the lungs regulate acid-base balance by removing CO2, converting it to carbonic acid and back, and driving hyperventilation during exercise to maintain pH.

Explore the acid-base balance in human physiology by examining acidosis and alkalosis, driven by CO2 and HCO3 changes; differentiate respiratory and metabolic causes to understand pH shifts.

Triggers metabolic acidosis by accumulating organic acids such as lactic acid, ketoacids, and uric acid. Exacerbates metabolic acidosis when circulatory shock, diabetes, and renal disease elevate these acids.

Body fluids exceed two thirds of body weight, with water forming most of this fluid; men are 60–65% water, women 50–80%, and a 70 kg person holds 40 L—stay hydrated.

Explore how body fluids support homeostasis by forming the internal environment that sustains cells, with water as the star player balancing glucose, amino acids, and oxygen to support life.

Keep your body's transport mechanism running by staying hydrated; water carries nutrients and removes wastes, delivering enzymes, hormones, and vitamins.

Water acts as the medium for cellular metabolic reactions, driving growth and function. Hydration fuels the tiny engines of life and keeps cells thriving.

Discover how water inside cells shapes tissue texture and why maintaining balanced hydration keeps tissues plump and healthy.

Learn how water regulates body temperature by cooling us through sweating when hot and retaining heat when cold, acting as a personal thermostat through hydration.

Explore the distribution of total body water (about 40 L), with intracellular fluid (22 L, 55%) and extracellular fluid (18 L, 45%), including interstitial fluid, lymph, plasma, and transcellular fluid.

Explore body fluids, from water and organic substances to inorganic ions. ECF is rich in sodium chloride and bicarbonate; ICF in potassium and magnesium, with pH 7.4 and 7.0.

Explore the indicator dilution method, injecting a known dye into the bloodstream, tracking its spread through body fluid compartments, and calculating total body water and fluid volumes.

Apply the indicator dilution method by introducing a marker into a body fluid compartment, ensure mixing, and sample to measure marker concentration with colorimetric or radioactive methods for fluid dynamics.

Explore the indicator dilution method for measuring extracellular fluid, plasma, and total body water. Inject dye, let it circulate, then measure concentration to calculate volumes.

Identify marker substances by selecting non-toxic compounds that mix thoroughly with the fluid compartment quickly, excrete at an appropriate rate, and avoid altering color or volume, ensuring accurate tracking.

Marker substances enable measurement of body fluid compartments, including total body water, extracellular fluid, plasma, interstitial, and intracellular volumes, clarifying fluid distribution; see table 6.2 for details.

Explore how body fluid concentration is expressed through osmolality, osmolarity, and tonicity, and learn how these concepts guide hydration and health decisions.

Explore how osmolality governs osmotic pressure and fluid balance by detailing concentration in osmoles per kilogram, critical for medicine and chemistry.

Explore osmolarity and its role in fluid balance, osmotic pressure, and water movement between ECF and ICF, with the osmolarity-osmolality distinction (less than 1%) clarified.

Explore mole and osmole concepts in chemistry, defining a mole as the molecular weight in grams and an osmol as that value divided by the number of free particles.

Explore how tonicity and effective osmoles like urea, alcohol, sodium, and glucose drive water movement between cell compartments, shaping effective osmolality and cellular hydration.

Identify tonicity as the measure of effective osmolality and classify fluids as isotonic, hypertonic, and hypertonic with lower osmolality, noting hydration, water movement, and potential cell swelling.

Isotonic fluids balance body osmolality and maintain osmotic equilibrium across cell membranes, with normal saline and 5% glucose as common examples.

Discover how hypertonic fluid, like a 2% sodium chloride solution, drives water out of cells, causing them to shrink, a process the caption calls exocytosis.

Explore how hypertonic fluids with less effective osmolality than body fluids push water into red blood cells, causing swelling and hemolysis through osmosis.

Discover how the hypothalamus detects changes in water levels and signals the kidneys to adjust water retention to maintain hydration.

Understand dehydration as water loss affecting energy and health, with needs 1 liter (2–3 for active people) and three levels: mild (5%), moderate (10%), severe (15%), with rehydration or hospitalization.

Diagnose dehydration types by water and sodium loss: isotonic (equal), hypertonic (more water loss than sodium, often with fever), and sodium-heavy loss (more sodium than water, as with diuretics).

Explore the causes of dehydration, including diarrhea and vomiting, renal and endocrine disorders, insufficient water intake, excessive sweating, and laxatives or diuretics.

Identify dehydration signs and symptoms from mild to severe, including dry mouth, thirst, and headaches. Stay hydrated to prevent organ damage and complications such as renal failure and shock.

Infant dehydration, often caused by severe diarrhea and vomiting due to infection, can be life threatening; recognize signs like dry mouth and lack of tears, seek medical advice promptly.

Aging increases dehydration risk due to greater fluid loss and reduced intake; stay aware, stay proactive, and learn strategies to prevent dehydration in elders.

Treat dehydration with oral rehydration therapy for mild cases using a solution of glucose, sodium chloride, potassium chloride, and sodium citrate. For very severe dehydration, administer intravenous water and electrolytes.

Explore water intoxication and overhydration, showing how excessive water dilutes electrolytes and can cause serious health issues. Learn to balance hydration by staying hydrated without overdoing it.

Water intoxication occurs when you drink more water than your body can handle, with risks including heart failure, renal disorders, ADH overproduction, infancy, and excessive intake or IV fluids.

Explore the signs and symptoms of water intoxication, highlighting brain vulnerability, early behavioral changes and drowsiness, then nausea, vomiting, weight loss, and later seizures or coma.

Carrying oxygen from the lungs to each cell, blood fuels growth and delivers nutrients and hormones. Defending against disease and removing waste, blood nourishes tissues and keeps the body healthy.

Arterial blood is scarlet red; venous blood is purple red. Adults have about five liters; newborns start at 450 ml; pH 7.4; viscosity five times water.

Blood consists of formed elements and plasma; plasma, 55% of blood, carries water, salts, enzymes, antibodies, clotting factors, albumin, and fibrinogen, and parts can be separated from plasma during donation.

Explore blood's three key players: red blood cells (erythrocytes) carry oxygen, white blood cells (leukocytes) defend the body, and platelets (thrombocytes) enable clotting.

Collect blood in a hematocrit tube with anticoagulant, spin at 3000 rpm for 30 minutes, revealing plasma 55%, red blood cells 45%, and the buffy coat for packed cell volume.

Transport nutrients, hormones, and proteins through the straw-colored liquid that makes up more than half of blood and contains 91% water, and helps keep the body functioning.

Explain how serum forms when fibrinogen converts to fibrin during clotting, trapping blood cells, and how centrifuging separates serum from the clot for clinical testing.

The blood delivers glucose, amino acids, lipids, and vitamins to tissues for growth, and transports oxygen, carbon dioxide, wastes to excretory organs, and hormones and enzymes, regulating water balance.

Explore plasma proteins, including serum albumin, serum globulin, and fibrinogen, their conversion to fibrin during blood clotting, and their crucial role in maintaining body functions.

Explore seven plasma protein separation methods, including precipitation, salting out with specific saturations, electrophoresis, cohn's fractional precipitation, ultracentrifugation, gel filtration, and immunoelectrophoresis to classify albumin, globulins, and fibrinogen.

Explore plasma proteins: fibrinogen has the highest molecular weight at 400,000 and albumin 69,000; albumin maintains about 25 mm Hg oncotic pressure, 1.026 specific gravity, and buffers blood's buffering action.

Trace the origin of plasma proteins from embryonic mesenchyme producing albumin to adult liver reticuloendothelial cell synthesis. Gamma globulin forms from B lymphocytes, with spleen, bone marrow, and tissues contributing.

Plasma proteins drive coagulation via fibrinogen, defend against pathogens as immunoglobulins, transport hormones and metals with albumin and globulins, and maintain colloidal osmotic pressure at capillaries.

The course explains the diverse roles of plasma proteins, including fibrinogen in coagulation, gamma globulins as antibodies, and albumin with globulins in transport, buffering, and osmotic pressure.

Set out to understand how albumin and globulin levels vary in opposite directions, and how changes in plasma proteins relate to hypoproteinemia, signaling health status.

Explore red blood cells, erythrocytes, non-nucleated haemoglobin carriers that transport oxygen and carbon dioxide, outnumbering white cells and platelets, with normal counts of 4–5.5 million per cu m.

Red blood cells form a biconcave disc, giving flexibility and a large surface area for rapid diffusion of oxygen and other substances, enabling easy capillary passage with minimal membrane tension.

Analyze normal size characteristics, including diameter about 7.2 micrometers (6.9–7.4), edge thickness 2.2 μm and center 1 μm, a biconcave shape with surface area 120 μm² and volume 85–90 μm³.

Explore the structure and energy of red blood cells, detailing non-nucleated mammalian RBCs, lack of DNA and mitochondria, glycolytic energy, and the crucial spectrin-based cytoskeleton.

Explore the unique properties of red blood cells, including rouleau formation, specific gravity, packed cell volume (hematocrit) at 45%, and suspension stability during circulation.

Discover how red blood cells live about 120 days, are broken down in the reticuloendothelial system, and tracked using radioisotope tagging to measure their disappearance from blood.

Older red blood cells age about 120 days; in the spleen they break apart, releasing hemoglobin for macrophages to recycle into iron, globin, and bilirubin excreted by the liver.

RBCs transport respiratory gases by delivering oxygen from lungs to tissues as oxyhemoglobin and moving carbon dioxide back as bicarbonate and bound forms, while buffering pH and determining blood groups.

Explore physiological polycythemia and how various conditions raise red blood cell count. From birth and high-altitude hypoxia to exercise, adrenaline and meals.

Identify physiological scenarios that lower red blood cell count, including deep-sea conditions with high blood oxygen tension, sleep, and pregnancy-related hemodilution from increased extracellular fluid and plasma volume.

Explore pathological polycythemia as an abnormal rise in red blood cells. Differentiate primary polycythemia vera from secondary polycythemia caused by hypoxia and erythropoietin-driven marrow stimulation.

Explore how red blood cell size varies, with venous blood slightly larger than arterial blood, and identify microcytes, macrocytes, and anisocytosis in iron deficiency, megaloblastic, and pernicious anemia.

Explore how red blood cells vary in shape under different conditions, including crenation in hypotonic environments, spherocytosis, elliptocytosis, and sickle cell crescent formation. Understand how these shapes influence oxygen transport.

Explore structural variations of red blood cells, such as punctate basophilic dots, goblet ring, and ring forms, linked to lead poisoning and certain anemias, including Howell-Jolly bodies.

Erythropoiesis, part of hemopoiesis, covers the origin, development and maturation of erythrocytes; autopoiesis defines the broader blood cell formation, with fetal life involving mesoblastic, hepatic, and myeloid stages.

Red bone marrow makes RBCs until age 20 from all bones. After 20, erythropoiesis shifts to membranous bones and ends of long bones, with shafts becoming yellow marrow.

Explain erythropoiesis by detailing hematopoietic stem cells in bone marrow as uncommitted pluripotent cells that form all blood types, later becoming committed; umbilical cord blood is a major source.

Split committed ahscs into two types; lymphoid stem cells form lymphocytes and natural killer cells, while colony forming blastocysts give rise to myeloid cells, including erythrocytes, granulocytes, monocytes, and platelets.

Trace the stages of erythropoiesis from cfu-e cells through pro erythroblasts, early to late normal blasts, and reticulocytes, culminating in mature erythrocytes ready to carry oxygen.

Trace the stages of erythropoiesis from CFU-derived proerythroblast to mature erythrocyte, including hemoglobin synthesis in intermediate normoblast, reticulocyte formation, and diapedesis into blood.

Explore the general factors driving erythropoiesis, including erythropoietin, thyroxine, hemopoietic growth factors, and vitamins, and trace the erythroblast maturation process from CFU to mature erythrocytes.

Vitamin B12, intrinsic factor, and folic acid drive maturation of erythropoiesis; deficiency causes macrocytic megaloblastic anemia due to impaired DNA synthesis and cell maturation.

Identify essential materials for hemoglobin synthesis in red blood cells; deficiencies cause anemia, involving proteins, amino acids, iron for heme, copper for absorption, cobalt and nickel for utilization, and vitamins.

Explore how hemoglobin, the iron-containing chromoprotein in red blood cells, carries oxygen and carbon dioxide, acts as a buffer, weighs 68,000, and shows age- and sex-related variation.

Hemoglobin transports gases by delivering oxygen from lungs to tissues and carbon dioxide from tissues to lungs, forming oxyhemoglobin in ferrous state and reversible CO2 binding that buffers acid-base balance.

Explore how hemoglobin, a conjugated protein of globin and the iron-containing heme pigment, features a porphyrin structure with four pyrrole rings linked by methane bridges.

Explore the two normal hemoglobin types, HbA and HbF, noting the birth-driven replacement, structural differences, and HbF's higher oxygen affinity with a leftward dissociation curve.

Identify abnormal hemoglobin variants from globin gene mutations and classify them as hemoglobinopathies or thalassemia disorders, including Hb S, C, E, M, and variants G, H, I, Barts, Kenya.

Identify abnormal hemoglobin derivatives such as carboxyhemoglobin and methemoglobin, their causes including carbon monoxide poisoning and nitrates and nitrite exposure, and the resulting tissue hypoxia.

Explore the synthesis of hemoglobin from proerythroblasts to reticulocytes, detailing heme production in mitochondria from succinyl-coa and glycine, and globin synthesis in ribosomes forming alpha, beta, gamma, and delta chains.

Explore iron's role in oxygen transport and storage. Understand heme and non-heme iron, intestinal absorption, transferrin transport, and ferritin or hemosiderin storage.

Anemia reduces RBC count, hemoglobin, and PCV, and arises from inherited disorders or environmental factors such as nutrition, infection, or exposure to drugs or toxins, with morphological and etiological classifications.

Explore the anemia spectrum by morphological and etiological classification, using MCV and MCHC to identify normocytic normochromic, macrocytic normochromic, macrocytic hypochromic, and microcytic hypochromic patterns.

Describe five etiologic anemia types—hemorrhagic, hemolytic, nutrition-deficiency, aplastic, and anemia of chronic disease—highlighting acute versus chronic blood loss and iron-related red cell changes.