05181 - Physiology

Learning outcomes

At the end of the course, the student will have the basic notion of the human body physiology at functional and molecular level. In particular, the student will know the fundamental vital mechanism of several organs, a necessary knowledge for researching, designing and using materials and machinery use in the field of medicine. 

Course contents

The cell and the transcellular and paracellular exchange processes

Fluid compartments of the body. Ionic composition of the intracellular and extracellular fluids. Selective permeability of the cell membrane. Transport of water and solutes across the cell membrane. Passive transport: simple diffusion and Fick's law; osmosis, facilitated diffusion (uniporters). Primary active transport: ATP-driven pumps. Secondary active transport: symporters; antiporters. Transport of water and solutes across epithelia. Capillary fltration according to the Starling-Landis hypothesis.

Resting membrane potential and action potential

Electrochemical equilibrium and Nernst equation. Membrane potential and Goldman equation. Voltage-dependent channels and excitability in cells of the nervous system, skeletal muscle, smooth muscle and heart. Genesis of the action potential: threshold membrane potential and self-regenerating mechanisms. Ionic conductances in the various phases of the action potential. Cycle of membrane excitability: refractory periods. Propagation of the action potential.

Synaptic transmission

Electrical synapses. Chemical synapses: synthesis, release and inactivation of neurotransmitters. Classification of neurotransmitters. Membrane receptors. Effects of binding of neurotransmitters to ionotropic and metabotropic receptors: excitatory and inhibitory postsynaptic potentials, changes in cellular metabolism and gene expression. Spatial and temporal summation of postsynaptic potentials. Presynaptic inhibition and facilitation. Synaptic transmission at the neuromuscular junction.

Sensory receptors

Classification of sensory receptors. Adequate stimulus and stimulation threshold. Signal transduction: generator potential and action potential propagation in nerve fibers. Encoding the intensity of sensory stimulation. Adaptation in sensory receptors. Receptive field of sensory receptors.

General somatic and special senses receptors

Receptors and afferent fibers of the tactile, kinesthetic, thermal and pain sensibility. Cellular organization of the retina and mechanism of phototransduction. Photopic and scotopic vision. Functional anatomy of the cochlea and vestibular apparatus. Transduction of sound and cochlear tonotopy Auditory thresholds. Responses of vestibular receptors to linear and angular acceleration.

Skeletal, smooth and cardiac muscle

Skeletal muscle: activation of the contractile mechanism; excitation-contraction coupling; innervation of fibers; muscle twitch and tetanic contraction; gradation of contractile force; isometric and isotonic contraction; length-tension relationship. Cardiac muscle: activation of the contractile mechanism; excitation-contraction coupling; length-tension relationship. Smooth muscle: classification; activation of the contractile mechanism; nervous and humoral regulation of contraction.

Spinal reflexes

Spinal reflex arc components. Myotatic (stretch) reflex. Muscle tone. Function of the gamma circuit. Inverse myotatic (stretch) reflex. Flexor withdrawal, crossed extensor reflex.

Dynamics of body fluids

Blood and air flow in circulatory and respiratory systems: Bernoulli's principle, laminar flow (Hagen-Poiseuille formula); turbulent flow (Reynolds formula). Distribution of resistance in the vascular bed and tracheobronchial tree. Changes of blood flow velocity and pressure in the different vessels of systemic circulation. Rheological properties of blood.

Somatosensory sensibility

Organization of somatosensory pathways of the body and the face. Thalamic and cortical somatosensory areas. Pain: nociceptive and neuropathic pain, hyperalgesia, referred pain. Peripheral modulation and central control of pain.

Control of Movement

Final common pathway: the motor neuron. Organization of descending motor pathways. Function of medial and lateral system pathways. Cortical and brainstem control of movement. Regulation of movement: the cerebellum (afferent and efferent morphofunctional organization) basal ganglia (morphofunctional organization, direct pathway and indirect pathway).

Autonomic Nervous System

Morphofunctional organization of the autonomic nervous system: sympathetic, parasympathetic and enteric divisions. Action of the sympathetic and parasympathetic systems on the main organs. Adrenal medulla. Central control of the autonomic function. Micturition. Thermogenetic and thermolytic mechanisms. Skin circulation.

Digestive system

Morphofunctional organization of the esophagus and stomach. Cephalic, oral, esophageal and gastric phases of motor, secretory and absorptive processes. Morphofunctional organization of the intestine. Intervention of the small intestine and colon in motor, secretory and absorptive processes,. Pancreatic and biliary secretions.

Functional organization of the vascular system

Elasticity and function of large arteries. Application of Laplace's law to blood vessels. Central and peripheral arterial pulse. Function of the arterioles. Regulation of capillary flow. Role of the endothelium and smooth muscle in the regulation of blood flow. Function of the lymphatic vessels. Function of the venous vessels.

Integrated control of the cardiovascular system

Central venous pressure. Integrated control of the cardiovascular system: curves of cardiac function, curves of vascular function. Relating cardiac function curves to vascular function curves.

Blood pressure and its regulation

Reflex regulation of arterial blood pressure: localization, structure and functional characteristics of the aortic and carotid baroreceptors; cardiac and vasomotor reflexes elicited by aortic and carotid baroreceptors. Vasomotor reflexes elicited by cardiac receptors. The renin-angiotensin-aldosterone system in blood pressure regulation.

Stroke Volume

Genesis and propagation of the cardiac impulse. Electromechanical coupling during the cardiac cycle. Movement of valves, changes in pressure and volume of atria and ventricles during the cardiac cycle. Duration of different phases of the cardiac cycle. Origin of heart sounds.

Cardiac Output

Stroke volume and cardiac output. Determination of the cardiac output by means of the Principle of Fick and the indicator dilution method. Pressure-volume relationship in the left ventricle. Heterometric (Frank-Starling mechanism) and homeometric (increased heart rate, response to the increase in diastolic pressure) intrinsic regulation of myocardial mechanical activity. Extrinsic regulation (nervous and humoral) of the electrical and mechanical myocardial activity. Indices of myocardial contractility.

Cardiac metabolism

Changes in coronary blood flow during the cardiac cycle. Nervous and humoral regulation of the coronary circulation. Cardiac metabolism. Work of the heart. Application of Laplace's law to the heart. Electrocardiography.

Dynamic respiratory mechanics

Functions of the respiratory tract. Action of the respiratory muscles. Pleural pressure. Changes in the alveolar and pleural pressure, in air flow during a respiratory cycle. Dynamic respiratory mechanics: flow and resistance in the airways; maximal expiratory flows; flow-volume diagrams; dynamic airways compression.

Static respiratory mechanics.

Static respiratory mechanics: pressure-volume curves of the lung, of the chest and of the chest-lung system; compliance; application of the Laplace's law to the lung; contribution of the surface tension to the pulmonary elasticity; role of pulmonary surfactant. Work of breathing.

Pulmonary gas exchange

Composition of atmospheric and alveolar air. Pulmonary ventilation and alveolar ventilation. Measurement of dead space. Alveolar-capillary barrier. Measurement of pulmonary diffusion capacity. Pulmonary circulation. Ventilation-perfusion ratio: regional differences in ventilation-perfusion ratio; excess of ventilation with respect to perfusion; excess of perfusion with respect to ventilation.

Transport of oxygen and carbon dioxide in the blood

Forms of oxygen transport in the blood. Functional significance of the hemoglobin dissociation curve. Quantitative aspects of the transport of oxygen in the blood. Types of hypoxia. Forms of transport of carbon dioxide in the blood. Functional significance of the curve of transport of carbon dioxide. Quantitative aspects of the transport of carbon dioxide in the blood. Interaction between the transport of oxygen and carbon dioxide.

Control of breathing

Ventilatory responses to changes in the arterial partial pressure of oxygen and carbon dioxide and concentration of hydrogen ion. Function of the peripheral and central chemoreceptors in the regulation of pulmonary ventilation. Interaction between chemical stimuli in the regulation of pulmonary ventilation. Control of breathing by pontine and medullary respiratory centers. Lung receptors and respiratory reflexes.

Functions of the renal glomerulus

Plasma and renal blood flow. Ultrafiltration process. Glomerular ultrafiltration rate: clearance of inulin; plasma creatinine. Filtration fraction. Autoregulation of renal blood flow and glomerular filtration rate.

Functions of the renal tubule

Absorption and secretion in the nephron. Reabsorption of sodium chloride and water. Control of renal potassium homeostasis. Renal clearance.

Regulation of body fluid osmolality

Fluid compartments of the body. Neurohypophyseal secretion of antidiuretic hormone. Renal mechanisms for concentration and dilution of urine. Osmolar clearance and free-water clearance.

Regulation of body fluids volume

Fluid compartments of the body. Effective circulating volume. Regulation of renal excretion of water and sodium chloride. Mechanisms of regulation of extracellular fluid volume: volume receptors; actions of the sympathetic nervous system, the renin-angiotensin-aldosterone system and natriuretic peptides.

Readings/Bibliography

Grassi, Negrini, Porro - Fisiologia Umana - Poletto Editore

Teaching methods

Lectures

Assessment methods

Written test with multiple and open answers.

Teaching tools

The material used in class will be made available on line.

Office hours

See the website of Matteo Cerri