Masters in Medical Physiology

Examine the SA node’s pacemaker potential from -60 to -40 mV, driven by funny current and T-type calcium influx, with depolarization via L-type calcium and autonomic regulation.

Explore vascular physiology, detailing the aorta's wind causal effect and elastic recoil, capillary exchange driven by hydrostatic and colloidal osmotic pressures, and venous lymphatic return.

Learn preload as end-diastolic volume and its dependence on venous return, venous constriction, and vasodilation, and afterload as aortic pressure set by total peripheral vascular resistance and arteriolar tone.

Learn how left ventricular pressure-volume loops map pressure and volume changes, including end diastolic and end systolic volumes, stroke volume, and conditions like aortic stenosis and regurgitation.

Kussmaul sign is the lack of a normal decrease or an actual increase in jugular venous pressure during inspiration, indicating right ventricular dysfunction seen in constrictive pericarditis and restrictive cardiomyopathy.

Explore jugular venous pressure waveforms - a, c, x, v, y waves - linking atrial contraction and atrial/ventricular events to conditions like tricuspid stenosis, pulmonic stenosis, tricuspid regurgitation, atrial fibrillation, and constrictive pericarditis.

Explore hemodynamics by analyzing laminar blood flow and Reynolds number, and apply Higgins (Poiseuille) formula showing blood flow depends on pressure difference and radius, inversely on length and viscosity.

Understand how central venous pressure, or right atrial pressure, rises in right- and left heart failure, tamponade, constrictive pericarditis, tricuspid disease, pulmonary hypertension or embolism, and falls with venous return.

Explore cardiac reflexes including Cushing's bradycardia with intracranial pressure, Bainbridge's tachycardia from increased venous return, Bezold-Jarisch bradycardia during myocardial infarction, and oculo-cardiac reflex effects from eye compression.

Explore the cardiac cycle’s phases—isovolumetric contraction and rapid/slow ejection, diastole’s relaxation and filling—plus S1, S2, S3, S4, ejection click, opening snap, preload, and end diastolic/end systolic volumes.

Learn how mean arterial pressure and pulse pressure shape blood pressure, and how baroreceptors in the carotid sinus and aortic arch regulate it via the medulla, with posture effects.

Describe the normal pulse waveform with systolic rise, diastolic drop, and the dicrotic notch, then summarize key abnormal pulses: dicrotic, bounding, pulsus alternans, paradoxus, parvus et tardus, and water hammer.

Understand the heart's nodal and muscular tissues, the action potential pathway from SA node to Purkinje fibers, and the spectrum of AV blocks (first to third degree) with AV dissociation.

Survey the Vaughan Williams classes of antiarrhythmic drugs: sodium, potassium, beta and calcium channel blockers; covering indications like wpw syndrome, post-mi ventricular tachycardia, and torsades de pointes.

The hypothalamus serves as the master regulator of the endocrine system. It coordinates anterior and posterior pituitary function through releasing and inhibitory hormones, linking thyroid, adrenal, and gonadal axes.

Explore pituitary stalk damage and Sheehan syndrome, prolactinomas, and their effects on hypothalamus-pituitary axis, including galactorrhea, amenorrhea, and bitemporal hemianopia.

Oxytocin and vasopressin are posterior pituitary hormones produced in hypothalamic nuclei and released via hypothalamo hypophyseal tracts; oxytocin triggers labor and milk ejection, vasopressin regulates water balance and vascular tone.

Explains how prolactinomas compress the optic chiasm to cause bitemporal hemianopsia, maps the six-layer lateral geniculate body and its magnocellular and parvocellular pathways, and outlines the pupillary light reflex.

Explore growth hormone physiology: hypothalamic control of the anterior pituitary, direct bone growth, and indirect actions via liver-derived IGF-1.

Explore how thyroid hormones are synthesized in follicular cells: iodide trapping, thyroglobulin, oxidation, organification, and coupling yield T3 and T4 stored in colloid, with calcitonin from parafollicular cells.

Explore how thyroid hormones T3 and T4 regulate heart rate, metabolism, adipose and protein breakdown, and CNS and bone development; and contrast hypothyroidism and hyperthyroidism with clinical features.

Explore how cortisol, produced by the adrenal cortex under ACTH, acts as a glucocorticoid and stress hormone; excess causes Cushing's syndrome with hyperglycemia, moon face, buffalo hump, and centripetal obesity.

Congenital adrenal hyperplasia is an autosomal recessive disorder causing cortisol and aldosterone deficiency with excess adrenal androgens, marked by elevated 17-hydroxyprogesterone and ambiguous genitalia in females.

This lecture explains calcium homeostasis through parathyroid hormone, calcitriol, and calcitonin, detailing how PTH and vitamin D raise blood calcium, while calcitonin lowers it.

Learn the pancreas' endocrine and exocrine roles, including insulin, glucagon, somatostatin, ghrelin, c-peptide as endogenous insulin marker, amylin, and amylin analog pramlintide in diabetes.

Pancreatic beta cells sense elevated glucose via Glut2 transport, raise ATP, close ATP-sensitive potassium channels, depolarize, open calcium channels, and exocytose insulin-containing granules. Sulfonylureas block ATP-sensitive potassium channels, boosting insulin.

Examine regulation of insulin release by glucose, glucagon, arginine and leucine, long-chain fatty acids, and parasympathetic activation, and outline diabetic ketoacidosis pathogenesis and its ketone-induced acidosis.

Insulin lowers blood glucose by promoting Glut4-mediated glucose uptake in skeletal muscle and adipocytes. It enhances glycogenesis and glycolysis while inhibiting glycogenolysis, gluconeogenesis, lipolysis, and ketogenic processes.

Explore the four layers of the gastrointestinal tract, the submucosal Meissner's plexus and the myenteric plexus driving secretion and motility, and how neural crest migration defects cause Ursprung disease.

Explore the spectrum of gastrointestinal secretions, including saliva, gastric, pancreatic, bile, and intestinal fluids; volume and reabsorption, saliva enzymes like salivary amylase and lingual lipase, Brunner's glands, and neural regulation.

Describe goblet cell mucus stained with alcian blue and Paneth and M cells; outline motilin and ghrelin roles in gastrointestinal motility via interstitial cells of Cajal.

Explore gastric glands, including surface and neck mucous cells, parietal and chief cells, and their products pepsinogen, gastric lipase, acid, intrinsic factor, and gastrin.

Explain digestion in the stomach and pernicious anemia, where autoantibodies attack parietal cells reducing hcl and intrinsic factor, causing B12 and iron deficiencies and megaloblastic anemia.

Identify absorptive sites for iron (duodenum), vitamin B9 (jejunum), B12 (terminal ileum); summarize iron regulation via DMT1, ferroportin, hepcidin, and hephaestin, including parasite-induced malabsorption.

Summarize pancreatic exocrine enzymes and zymogens, such as trypsinogen and chymotrypsinogen, and how secretin and cholecystokinin regulate bicarbonate secretion, bile release, gallbladder contraction, and gastric emptying.

Describe how the liver produces about 500 ml of bile daily, comprising bile acids, bile salts, bilirubin and biliverdin pigments, cholesterol, water, and electrolytes, to emulsify fats.

Introduce the central nervous system and peripheral nervous system, detailing brain and spinal cord, cranial and spinal nerves, and sensory afferent and motor efferent pathways with ascending and descending tracts.

Explore the sensory nervous system, outlining general and special senses, receptors, the three-order neuron pathway, and the dorsal column versus anterolateral pathways carrying advanced versus primitive sensations.

Receptors convert stimuli into electrical impulses for first-order neurons, detailing tactile, nociceptive, proprioceptive, thermoreceptive, and photoreceptive modalities and concepts like receptive fields, density, and two-point discrimination.

Describe the five reflex components—receptor, afferent, center, efferent, and response—through stretch reflex and inverse stretch reflex, highlighting Golgi tendon organs and group one B fibers.

Explore the four touch receptors—Meissner's corpuscles, Merkel cells, Pacinian corpuscles, and Ruffini endings—and their fast and slow adapting responses, via Aβ touch fibers and nociceptors with Aδ and C fibers.

Understand somatosensory pathways, including dorsal column and anterolateral tracts, their crossings, thalamic ventral posterolateral nucleus, and the somatosensory cortex area 312.

Explain gate control theory: pain signals modulate at spinal cord via inhibitory interneurons and second-order neurons. Activate non-painful stimuli to trigger Aβ fibers and inhibit second-order neurons, reducing pain transmission.

Lower motor neurons originate in the ventral horn, dividing into alpha and gamma types that innervate extrafusal and intrafusal fibers of the muscle spindle, with gamma neurons maintaining tone.

Explore descending motor pathways, including corticospinal (pyramidal) tracts and extrapyramidal tracts, their cortical origins, pyramidal decussation, and their roles in fine distal movements versus gross posture and coordination.

Explore upper motor neuron and lower motor neuron lesions, detailing spastic and flaccid paralysis, hyperreflexia and hypotonia, muscle atrophy, fasciculations, and the Babinski sign.

Explore syringomyelia, a cervical syrinx causing dissociative sensory loss with cape-like loss of touch, pain, and temperature, while dorsal column sensations remain intact.

The basal ganglia are misnamed, as basal nuclei coordinating motor programs inhibit movements via the striatum, globus pallidus, and substantia nigra, with dopamine modulating two pathways to enable movement.

Explore electroencephalography (EEG) and Berger waves, outlining alpha, beta, gamma, theta, and delta frequencies and their links to relaxation, active thinking, memory formation, and deep sleep.

Explore how learning builds knowledge and memory. Distinguish working, short-term, and long-term memory; explicit vs implicit, including semantic, episodic, and procedural memory, priming, and synaptic plasticity.

The hypothalamus orchestrates sleep-wake cycles, circadian rhythm, and body temperature via the suprachiasmatic, anterior, and posterior nuclei, and regulates feeding through lateral, ventromedial, and arcuate nuclei as integration centers.

Explore the two sleep phases—NREM and REM—and the four NREM stages, including theta, delta, sleep spindles, and K complexes, plus REM's paradoxical beta activity and PGO spikes.

Learn tongue motor innervation by hypoglossal nerve, palatoglossus via the wago complex. Identify sensory pathways: anterior two-thirds taste via chorda tympani; posterior and base via ninth and tenth cranial nerves.

Explore how retina rods and cones transduce light into signals for central and peripheral vision, color perception. Trace the optic nerve, chiasm, and lateral geniculate pathway to calcarine cortex.

Learn how hearing and balance arise from outer, middle, and inner ear structures, including the cochlea with organ of Corti, hair cells, utricle, saccule, and semicircular canals.

Explore renal physiology by examining kidney functions, including blood filtration, nitrogenous waste excretion, erythropoietin and renin production, vitamin D activation, acid-base balance, and nephron anatomy.

Explore how renal blood flow and renal plasma flow influence filtration fraction and GFR, and compare cortical and juxtamedullary nephrons in urine concentration.

Explore glomerular filtration: plasma moves through endothelial fenestrations, basement membrane, and podocyte slit diaphragms, with hydrostatic and osmotic forces shaping a 125 ml/min GFR and size- and charge-based selectivity.

Discover how afferent and efferent arteriole tone, mesangial cell dynamics, and tubuloglomerular feedback autoregulate GFR, modulated by Angiotensin II, norepinephrine, and nitric oxide.

The proximal convoluted tubule reabsorbs 70% of water, sodium, and most solutes (glucose, amino acids, bicarbonate); glucose reabsorption uses sodium-glucose cotransport (SGLT2) and exits via Glut transporters, keeping filtrate isotonic.

Explain the loop of Henle's water-permeable descending limb and the diluting ascending limb, with NKCC transport creating medullary hyperosmolarity, and how loop diuretics and Bartter syndrome alter this system, indomethacin.

Explore the distal convoluted tubule and its transporters, including the sodium chloride symporter, TRPV5 calcium channel, and calcium exchanger, guided by parathyroid hormone for calcium reabsorption.

Explore cortical and medullary collecting ducts, including principal and intercalated cells, and how aldosterone and vasopressin regulate ENaC and proton secretion.

This lecture details Conn syndrome due to adrenal adenoma producing excess aldosterone, causing hypertension, hypokalemia, and alkalosis, and contrasts it with Liddle syndrome while noting spironolactone therapy and aldosterone escape.

This lecture explains the renin angiotensin aldosterone system (raas), which raises blood pressure by activating renin release, forming angiotensin ii in the lungs, causing vasoconstriction and aldosterone-mediated sodium reabsorption.

Explore antidiuretic hormone, or vasopressin, produced in the hypothalamus and stored in the posterior pituitary, and its role in water reabsorption via V2 receptors and aquaporin-2 channels.

Bladder innervation uses sympathetic T10–L2 and parasympathetic S2–S4, with pudendal nerve controlling the external sphincter; micturition hinges on sacral reflexes and brain centers.

The glucose titration curve shows filtration, reabsorption, and excretion of glucose as plasma levels rise, with reabsorption saturating at 375 mg/min and a renal threshold of 200 mg/dL.

Understand acid-base balance through bicarbonate buffering, carbonic acid formation via carbonic anhydrase, and renal and pulmonary regulation of acidosis and alkalosis, including urinary buffers phosphate and ammonia.

Trace the 23 airway generations from trachea to alveolar sacs, define the conducting and respiratory zones, and summarize bronchodilation and asthma pharmacology.

Explore the conducting zone, its pseudostratified ciliated columnar epithelium and mucociliary escalator, and how basal and Clara cells act as stem cells, with Kartagener syndrome and cystic fibrosis.

Discover the respiratory zone anatomy, including type I and II pneumocytes and surfactant. Explore surfactant composition, fetal lung maturity tests, and prevention of hyaline membrane disease in preterm birth.

Explore alveolar ventilation and pulmonary circulation, define alveolar ventilation and alveolar gas exchange, and apply the alveolar gas equation and Bohr's equation to assess oxygenation.

Powerful active inspiration uses diaphragm contraction and chest wall muscles. In rest and breathing, intrapleural and intra-alveolar pressures shift, and transpulmonary pressure keeps alveoli open, with expiration being passive.

Explore compliance and elastance in the lung, defining stretchability and elastic recoil, note static, dynamic, and specific compliance, surface tension, and emphysema and fibrosis as examples.

In pulmonary circulation, hypoxia triggers vasoconstriction to divert blood from poorly oxygenated regions to healthy tissue, through oxygen-sensitive potassium channels that depolarize smooth muscle and induce calcium-driven contraction.

Use flow volume loops to interpret inspiratory and expiratory curves, residual volume, and total lung capacity, distinguishing obstructive (left shift, expiratory curving) from restrictive (right shift, reduced volumes).

Apply Fick's law to gas diffusion, linking diffusion to concentration gradient, surface area, and membrane thickness, noting emphysema reduces surface area and fibrosis thickens membranes, and summarize with DLCO.

Define the four lung volumes—tidal volume, inspiratory reserve volume, expiratory reserve volume, residual volume—and show capacities: inspiratory capacity, functional residual capacity, vital capacity, and total lung capacity.

Explains the oxygen hemoglobin dissociation curve, lung 100 mmHg saturation and tissue 40 mmHg saturation, defines P50, and contrasts right shift (low affinity) with left shift (high affinity).

Examine how lung perfusion, five liters per minute, varies from apex to base in a low-pressure, highly compliant pulmonary circulation, where arteries carry deoxygenated blood.

Relate intrapleural pressure changes to tidal volume to map lung compliance on the pressure–volume loop, noting hysteresis from surfactant and inspiration versus expiration, including emphysema and fibrosis.

Explain the ventilation-perfusion ratio (V/Q), noting apex V>Q and base Q>V, with values near 3.2 and 0.6, and list V/Q mismatch causes like pulmonary embolism and airway obstruction.

Explain how oxygen is transported as oxyhemoglobin with 3% dissolved, and how carbon dioxide travels as bicarbonate, with Bohr and Haldane effects governing loading at lungs and unloading at tissues.

Explore how respiration is regulated involuntarily by brainstem centers, including the medulla's dorsal and ventral respiratory groups and the pre-botzinger complex, with pontine modulation from the pneumotaxic and apneustic centers.

Explore hypoxia and its four types—hypoxic hypoxia, anemic hypoxia, stagnant hypoxia, and histotoxic hypoxia. Learn the basics of oxygen transport, including partial pressure, dissolved oxygen, oxyhemoglobin, diffusion, and cyanosis.

Hypoxia reduces tissue oxygen, triggers systemic vasodilation to increase flow, while pulmonary vessels vasoconstrict to divert blood to healthy areas, via closure of oxygen-sensitive potassium channels, depolarization, and calcium-driven contraction.

Explore how pontine and medullary centers regulate respiration and how lesions at different sites cause apnea, irregular breathing, or Cheyne-Stokes and Kussmaul patterns.

Explore the major respiratory reflexes, including the hering-breuer inflation reflex that prevents hyperinflation, the paradoxical reflex aiding newborn lung inflation, and the j reflex guarding against edema via the vagus.

Explain how carbon dioxide is transported from tissues to lungs, primarily as bicarbonate with chloride shift, and how oxygen binding triggers Haldane and Bohr effects during gas exchange.

Understand underwater respiration and how depth affects lung pressure and gas exchange. Learn how scuba gases, especially heliox, reduce nitrogen narcosis and decompression sickness.

explains how reduced barometric pressure at high altitude lowers alveolar oxygen, causing hypoxic hypoxia, and outlines acclimatization through hyperventilation, erythropoiesis, diffusion gains, and 2,3-bisphosphoglycerate effects, plus AMS and edema management.

Explore male reproductive physiology, including hypothalamic control of FSH and LH, Leydig and Sertoli cell roles, spermatogenesis, and epididymal maturation.

Explore how estrogens and androgens regulate development and sexual traits, derived from cholesterol and bound to sex hormone binding globulin. Learn about GnRH, FSH, LH, and pulsatile versus continuous signaling.

Trace how GnRH regulates FSH and LH to drive Sertoli and Leydig cell function, producing testosterone and DHT with implications for puberty, fertility, BPH, and androgen insensitivity.

Demonstrates the two-cell, two-hormone estrogen synthesis in the ovary, with LH/FSH acting on theca and granulosa cells to produce estradiol, plus progesterone, pregnancy, menopause, and contraception concepts.

Explore gametogenesis, detailing spermatogenesis from spermatogonia to spermiogenesis and oogenesis from oogonia to fertilization. Understand diploid to haploid transitions, meiosis stages, and the roles of Sertoli and Leydig cells.