COURSE CALENDAR

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Medical Physiology course structure and syllabus will be discussed. The central themes of Medical Physiology will be introduced as a prelude to our organ systems approach of course content. These central themes include: structure and function relations, regulation of internal environments, positive and negative feedback, biological control systems, adaptation, and homeostasis.

   

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The different kinds of protein-mediated solute transport are described. The role of these transport mechanisms in the development and maintenance of homeostasis are described in terms of the "pump-lead" hypothesis. Primary and secondary active solute transport are compared and contrasted.

   

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Osmosis is described in terms of the relevant driving force. The central role of the biological membrane to the phenomena of osmosis is emphasized. The importance of osmosis to physiology is discussed. The concepts of osmolarity and tonicity of fluids are described.

   

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The origin of biological membrane potentials is described in terms of transmembrane ion concentration differences and the relative permeability of the membrane to the dominant physiologic ions. Students are presented with a model to understand how membrane potential can change in response to physiologic signals.

   

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The "sodium hypothesis" of Hodgkin and Katz. The permeability changes that underlie the various phases of the nerve action potential. The events that take place during synaptic transmission, and how this relates to the generation of action potentials.

   

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The events that take place during synaptic transmission, and how this relates to the generation of action potentials.

   

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This lecure covers three types of muscle; the similarities and differences of skeletal and cardiac ultrastructure; a 'sarcomere' and the major contractile proteins associated with this structure; the sliding filament theory and its relationship to force generation; the cross bridge cycle for striated muscle contraction, the role of ATP in the cross bridge cycle, and how the level of ATP is maintained.

   

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Comparison of the role of extracellular calcium in excitation-contraction coupling in skeletal and cardiac muscle; how a nerve action potential initiates excitation-contraction coupling in muscle; the role of the T-tubule and sarcoplasmic reticulummembrane systems in excitation- contraction coupling, and the role of intracellular calcium in skeletal and cardiac muscle during excitation-contraction coupling.

   

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Isometric and isotonic contraction and what type of information can be obtained from each type of measurement; the length-tension curve and how it relates to muscle structure; the differences between the length-tension curve for skeletal and cardiac muscle and how these differences relate to the physiological function of the two muscle types; a force-velocity curve and the factors that govern its shape in skeletal and cardiac muscle; the difference between a twitch and a tetanus skeletal muscle; the motor unit and how motor units are used in muscle contraction.

   

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Isometric and isotonic contraction and what type of information can be obtained from each type of measurement; the length-tension curve and how it relates to muscle structure; the differences between the length-tension curve for skeletal and cardiac muscle and how these differences relate to the physiological function of the two muscle types; a force-velocity curve and the factors that govern its shape in skeletal and cardiac muscle; the difference between a twitch and a tetanus skeletal muscle; the motor unit and how motor units are used in muscle contraction.

   

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Basic principles of a smooth muscle contraction. The differences in regulation of smooth muscle as compared to striated muscle. How excitation is coupled to contraction in smooth muscle. How calcium sensitivity of contraciton can be modulated and the basic properties of the latch state.

   

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The lecture introduces the control systems theory concepts of "set point," "error signal" and "feedback," then illustrates how hypothalamic control centers seem to adhere to these concepts. There is a detailed explanation of short and long-term setpoints for body weight, and of the variety of endocrine feedback loops affecting feeding and satiety. A shorter description of the hypothalamic control of body fluid volume and osmolarity follows. The lecture concludes with short summaries of hypothalamic control of circadian rhythms and of hypophyseal function.

The lecture begins with the applied physics of heat transfer, covering radiation, evaporation, conduction and convection. This is followed by an explanation of the physiological mechanisms affecting these heat loss routes, and a description of the integrated hypothalamic control of body temperature. Heat acclimatization, fever, hypothermia, hyperthermia and heat stroke are discussed briefly.

   

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Chemical messengers and their receptor systems; the concepts of turnover, up and down regulation, and various types of feedback; euglycemic glucose clamping: the test and its rationale; the concept of metabolic clearance rate, and its significance.

   

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The functional anatomy of the hypothalamus and of hypothalamic pathways to the pituitary; the thermoregulatory functions of the hypothalamus; the hypothalamic hormones and their functions; the hormones released by the anterior pituitary: Growth Hormone: long-term effects, metabolic effects, release regulators and feedback regulation; ACTH: structure, release regulators and feedback loops, target tissues and effects; TSH, FSH, LH and PRL: details in later lectures; the hormones released by the posterior pituitary: ADH: release regulators, target tissues and effects; Oxytocin: release regulators, target tissues, effects.

   

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The synthesis and release of T3 and T4: thyroglobulin synthesis, iodine handling, coupling, storage, secretion, plasma transport. How TSH controls synthesis and release of T3 and T4; the relative importance of the various factors which control T3 and T4 activity: TRF and TSH, feedback loops, inhibitory factors; the actions of the thyroid hormones, the symptoms and the assessment and treatment options for cases of hypo- and hyperthyroidism.

   

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Subdivisions of the adrenal cortex (zona glomerulosa, zona fasciculata and zona reticularis), the hormonal products of each and their major effects. The ultrastructural features characteristic of cells from each region. The chromaffin cells of the adrenal medulla and their products. Blood supply to the chromaffin cells. Glucocorticoid induction of PNMT activity. Mention of adrenal dysfunction including pheochromocytoma, Cushing's Syndrome, Conn's Syndrome & Addison's Disease.

   

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A quantitative understanding of plasma calcium concentration, and of the roles of gut, kidneys, bone, and plasma proteins in its maintenance; the regulatory roles of PTH, calcitonin, Vitamin D, prolactin and other hormones; some of the conditions during which calcium mobilization takes place: chronic acidosis of renal failure, osteoporosis of menopause, rickets.

   

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The structure, synthesis and release patterns of insulin; how insulin binds to its target cell receptor and triggers post-receptor effects; the actions of insulin on its target tissues; the principal factors which increase or inhibit insulin release; the actions of glucagon and the factors affecting its release; the sources and actions of somatostatin and pancreatic polypeptide.

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Cell and muscle physiology teaching team members answer student questions.

   

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Basic principles of cellular electrophysiology are reviewed and extended into specific aspects of cardiac myocyte electrophysiology, including an in-depth discussion of resting membrane potential and action potentials in working myocytes (fast-acting potentials) and pacemaker cells (slow potentials). The normal sequence of cardiac depolarization is discussed and basic conduction arrthymias are defined from a pathophysiological perspective.

   

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The concept of dipole movements is reviewed, leading to a discussion of how they generate the electrocardiogram. The electrical connections used to record the electrocardiogram are presented and the scaler EKG is presented in detail. Criteria for normal EKGs are defined and recognition of abnormal EKG patterns is discussed.

   

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This lecture discusses in detail the etiology and synchronization of the various events in the cardiac cycle: blood pressures in atria, ventricles and arteries, heart valves, heart sounds, and the ECG. It also presents four factors affecting the force of ventricular contraction, pre-load, after load, inherent contractility and the Law of LaPlace. Cardiac output: its determinants, its variations and its measurement are the focus of this lecture. Cardiac metabolism, work and efficiency are covered and pressure-volume loops are presented. There is an introduction to cardiac function curves and the concept of ventricular failure.

   

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This lecture discusses in detail the etiology and synchronization of the various events in the cardiac cycle: blood pressures in atria, ventricles and arteries, heart valves, heart sounds, and the ECG. It also presents four factors affecting the force of ventricular contraction, pre-load, after load, inherent contractility and the Law of LaPlace. Cardiac output: its determinants, its variations and its measurement are the focus of this lecture. Cardiac metabolism, work and efficiency are covered and pressure-volume loops are presented. There is an introduction to cardiac function curves and the concept of ventricular failure.

   

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Effects of vessel architecture on blood flow. Velocity and pressure profiles in various regions of the body. Consequences of changing blood properties on flow. Effects of turbulence and vascular compliance on flow patterns. Forces driving flow in the venous system.

   

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Components of the microvasculature. Pathways for exchange of nutrients and waste products across the capillary wall. The role of the lymphatics. Forces driving fluid movement in and out of capillaries. Mechanisms for controlling blood flow into capillary beds (metabolic, myogenic, humoral, neural).

   

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Unique flow patterns in coronary circulation, susceptibility of subendocardium to ischemia, role of adenosine in regulating flow. The blood-brain barrier, role of CO2 in regulating cerebral flow, the CNS ischemic response and the Cushing Reaction. Role of cutaneous circulation in heat conservation and exchange, central control of cutaneous circulation. Diversity of organs served by the splanchnic circulation, susceptibility of villi to ischemic damage. Flow patterns in skeletal muscle: active, post-exercise and reactive hyperemia.

   

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Distinct features of the coronary circulation and its regulation. Origins of the unusual flow patterns through the coronary circulation are considered with reference to myocardial performance and susceptibility to ischemia.

   

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The mechanisms governing blood flow to the capillary beds is discussed. The concept of autoregulation of flow is defined and the role of the endothelium in controlling flow is reviewed.

   

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The role of the veins as a reservoir for blood. Effect of gravity on venous presures. Limits that the vasculature places on cardiac performance, as depicted in cardiovascular function curves (Guyton curves). How Guyton curves can be used to predict the body's response to alterations in cardiovascular performance.

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Three sessions review various psychosocial aspects of cornoary artery disease. Initial session reviews the data which establishes a link between psychosocial factors and the development, progression, and management of coronary artery disease.

   

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The pathophysiology of heart failure and circulatory shock are discussed in the context of the integrated renal and neural control of cardiovascular function. The importance and mechanisms of maintaining arterial pressure in the face of a wide range of pathological conditions are presented.

   

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A patient describes surviving myocardial infarction to his electrophysiologist. The genesis of arrhythmias is discussed, along with treatment options and strategies.

   

   

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The adjustments in critical cardiovascular parameters during physical activity are discussed, including arterial and venous pressure, heart rate, stroke volume, contractility, and ejection fraction. The long-term impact of chronic physical training on cardiovascular function and performance is presented, including how this activity augments cardiovascular performance and its ability to respond to physical stress.

   

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The blood-gas barrier and physical contrraints to the respiratory system will be presented. Pulmonary pressure will be defined and described.

   

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Normal values will be presented along with the mechanisms of ventilation. Gas partial pressures and the alveolar gas equation will be used to demonstrate changes in ventilation.

   

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Pulmonary function testing will be discussed and demonstration of the assessment of lung volumes and capacities will be undertaken. Restrictive and obstructive pulmonary disorders will be related to normal values to assist in interpreting these tests.

   

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Compliance of the lung and chest wall will be presented. The law of Laplace, surfactants, and surface tension will also be presented. Infant Respiratory Distress Syndrome will be discussed as it relates surfactants.

   

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Airway resistance and work of breathing will be presented. Emphysema and effects of age and smoking will be used to reinforce these physiological concepts.

   

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Effects and control factors of pulmonary vascular resistance will be presented. Microcirculatory issues in the pulmonary capillary will be discussed and related to possible ways this may affect gas exchange.

   

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Gas exchange in the lung and tissue will be presented. The concept of diffusion capacity will be applied as it relates to gas exchange in the lung. Oxygen-hemoglobin dissociation curves will be discussed as they relate to oxygen loading and unloading. The transportion of carbon dioxide will also be incorporated in the discussion.

   

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Ventilation and perfusion will be discussed separately then presented together as it relates to ventilation-perfusion ratios. The upright lung will be used as a model of alterations in ventilation-perfusion ratios.

Medullary control centers of respiration will be presented. Central and peripheral chemoreceptors will be discussed and the responses to the partial pressure of oxygen and carbon dioxide will be explained. Additional lung receptors that respond to chemical or mechanical stimulation will also be presented.

   

Preceding lecture material is reviewed and illustrated by case studies and specific physiology questions.

   

Preceding lecture material is reviewed and illustrated by case studies and specific physiology questions.

   

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Discussion of the organismal defenses against acid-base derangements, based on analysis of the Henderson-Hasselbach equation and the pH-bicarbonate diagram. Included: renal reabsorption of bicarbonate in the glomerular filtrate, "new" bicarbonate formation in the kidneys, and urinary excretion of protons.

   

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Medullary control centers of respiration will be presented. Central and peripheral chemoreceptors will be discussed and the responses to the partial pressure of oxygen and carbon dioxide will be explained. Additional lung receptors that respond to chemical or mechanical stimulation will also be presented.

   

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The first half of this lecture introduces the function and regulation of the gastrointestinal system. At the conclusion of the lecture you should know the basic functions and general regulatory mechanisms of the GI tract. The second half reviews the properties of transporting epithelia and its role in GI physiology. Emphasis is placed on how the structure of the epithelia contributes to the establishment of solute concentration and electrical gradients, water permeability, and the link between solute and water coupling.

   

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This lecture focuses on the motility and secretory functions of the upper GI tract, the mouth, pharynx and esophagus. You should fully understand the process of swallowing and esophageal transit, including the neural regulation of these processes. You should know how saliva is produced, its function, composition, and how it is regulated. The understanding of saliva production requires knowledge of the structure of the salivary gland.

   

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The focus of this lecture is the study of the motility and secretion processes of the stomach. At the end of the lecture you should have a detailed understanding of these processes, including how contractions are generated, regulation of gastric emptying, composition of gastric secretions, transporters involved in acid secretion, and the regulation of acid secretion.

   

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Reviews gross and microanatomical relationships key to understanding functions of absorption and secretion in this region of the GI tract. Small intestine motility patterns are described for "resting" and "working" small intestine, including Migrating Motility Complexes (MMCs). Mechanisms, functions and regulation of small intestinal secretions, including pancreatic secretions and their controls, are discussed.

   

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This lecture discusses the synthesis and composition of bile in the liver, the function of the gallbladder as bile moves between the liver and small intestine, and the role of GI hormones during bile secretion. Additionally, the role of pancreatic lipase in the digestion of fats, as well as the mechanism by which lipid digestion products are absorbed into intestinal epithelial cells and lipids re-synthesized is discussed. The absorption of fat-soluble vitamins is also addressed

   

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Histological characteristics of large intestine, appendix, and anorectal junction, including hemorrhoidal veins and the voluntary and involuntary sphincters.

   

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self-study materials and information will be placed on the physiology website

   

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We have studied the gastrointestinal tract functions of motility, secretion, digestion and absorption from the point of input to output. Does each segment of the gastrointestinal tract act independently of the other segments? The answer is a resounding no. The gastrointestinal system acts as a unit to carry out the important task of digesting and absorbing nutrients from food and the elimination of solid waste. The purpose of this lecture is to examine how the gastrointestinal system functions as a unit.

   

Review of functional renal anatomy. Concept of mass balance and its application to the assessment of glomerular filtration rate (GFR) and renal plasma flow. The concept and applications of renal clearance.

   

Proximal tubular mechanisms of reabsorption and secretion.

   

Reabsorption and secretion in the loop of Henle, distal tubule and collecting duct. Functions of aldosterone.