05181 - Physiology

Course Unit Page

Academic Year 2018/2019

Learning outcomes

At the end of the course, students should be able to understand the vital functions of the human body, and the mechanisms underlying their regulation. More specifically students will: - know the electrophysiological and functional mechanisms of communication systems in biological membranes and the functions of individual cells; - know the mechanisms underlying the nervous, cardiovascular, renal, respiratory and digestive functions; - know the mechanisms of vegetative functions and basic principles of endocrinology; know the mechanisms underlying the sensory and motor functions of the stomatognathic system; • owns the basis for the interpretation of the physio-pathological processes that affect the stomatognathic system.

Course contents

Biophysics

RESTING MEMBRANE POTENTIAL

Ionic composition of the intracellular and extracellular fluids. Selective permeability of the cell membrane. Electrochemical equilibrium and Nernst equation. Equilibrium potentials of the major ions with the Nernst equation. Relationship between diffusible ion permeability and membrane potential: equation of the membrane conductance. Functions of the sodium / potassium pump.

ACTION POTENTIAL

Excitable membranes and voltage-dependent channels. Genesis of the action potential: threshold membrane potential and regenerative mechanism. Conductances and ionic fluxes 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. Membrane receptors. Effects of the binding of neurotransmitter to ionotropic and metabotropic receptors. Excitatory and inhibitory postsynaptic potentials. Spatial and temporal summation of postsynaptic potentials. Presynaptic inhibition. Classes of neurotransmitters. Neuromuscular transmission.

SENSORY RECEPTORS

Classification of sensory receptors. Adequate stimulus and stimulation threshold. Mechanism of signal transduction and relationship between generator potential amplitude and frequency of the propagated signals. Adaptation of the receptors. Receptive fields.

PHYSIOLOGY OF THE SKELETAL AND SMOOTH MUSCLE

Structure of the skeletal muscle. Synaptic transmission at the neuromuscular junction. Activation of the contractile mechanism. Isotonic and isometric contraction. Twitch and tetaniic contraction. Length-tension curve. Innervation of the skeletal muscle. Neuromotor unit. Gradation of the contractile force. Classification of the smooth muscle. Activation of the contractile mechanism. Nervous and humoral regulation of contraction.

Neurophysiology

MECHANORECEPTIVE SENSIBILITY

Receptors and afferent fibers of tactile and kinesthetic sensibility. Organization of the sensory pathways of the mechanoreceptive sensibility of the body. Cortical somatosensory areas.

NOCICEPTION AND THERMAL SENSIBILITY

Receptors and afferent fibers of nociception and thermic sensibility. Organization of the sensory pathways of pain sensation and thermic sensibility. Types of pain. Hyperalgesia. Referred pain. Peripheral modulation and central control of pain.

SOMATOSENSORY SENSIBILITY OF THE FACE AND ORAL CAVITY

Tactile, thermal and nociceptive sensibility of the face and oral cavity. Sensory nerves. Central pathways.

SPECIAL SENSES: TASTE AND SMELL

Gustatory receptors. Transduction of taste stimuli. Taste pathways. Olfactory receptors. Transduction of olfactory stimuli. Olfactory pathways.

SPINAL REFLEXES

Myotatic (stretch) reflex, muscle tone, role of the gamma circuit. Inverse myotatic reflex. Flexor reflex, crossed extensor reflex.

CONTROL OF MOVEMENT

Final common pathway: the motor neuron. Organization of descending motor pathways. Pathways of the lateral system and medial system and their function. Cortical control of movement. Role of the cerebellum and basal ganglia in the regulation of movement..

AUTONOMIC NERVOUS SYSTEM

Morphofunctional organization of the autonomic nervous system. Neurotransmitters and receptors. Actions of the sympathetic and parasympathetic systems on the main organs. Adrenal medulla.

Digestive System

CHEWING

Muscles and mechanics of chewing. Control of chewing. Chewing reflexes.

SWALLOWING

Phases of swallowing and their control. Swallowing disorders.

GASTRIC AND INTESTINAL MOTILITY

The enteric nervous system. Filling and emptying the stomach. Regulation of gastric emptying. Movements of the small intestine: segmentation and peristaltic movements. Movements of the colon. Neural and chemical control of intestinal motility. Defecation.

SECRETION, DIGESTION AND ABSORPTION IN THE DIGESTIVE TRACT

Salivary secretion. Gastric secretion. Neural and chemical control of salivary and gastric secretions. Composition and functions of the pancreatic juice. Neural and chemical control of pancreatic secretion. Composition and functions of the bile. Nervous and humoral control of the secretion of bile.

Cardiovascular system

HEMODYNAMICS

Organizational principles of the cardiovascular system. Laminar flow: Hagen-Poiseuille law. Resistance of the systemic and the pulmonary circulation. Blood flow velocity and pressure in the different vascular segments of the systemic circulation. Resistances along the systemic circulation (in series and in parallel resistors). Blood viscosity. Turbulent flow: Reynolds formula.

BLOOD PRESSURE AND ITS CONTROL

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

DETERMINATION OF BLOOD PRESSURE (Laboratory Practicals)

Measuremen of blood pressure by Riva-Rocci sphygmomanometric method. Systolic, diastolic, and differential pressure.

CARDIAC ELECTRICAL ACTIVITY

Electrical activity of the specific myocardium (nodal tissue and Purkinje fibers) and common myocardium. Relationship between electrical and mechanical events in the common myocardium cells. Generation and propagation of excitation. Effects of sympathetic and parasympathetic impulses on the electrical and mechanical activity of the myocardium.

CARDIAC CYCLE

Correlation between electrical and mechanical events of the cardiac cycle. Position and movements of valves, atrial and ventricular pressures and volumes during the cardiac cycle. Duration of the phases of the cardiac cycle. Heart sounds and their genesis.

ELECTROCARDIOGRAPHY (Laboratory Practicals)

Physical principles of electrocardiography: volume conductor, equivalent electric dipole and electric field vector. Recording techniques of cardiac electrical activity: bipolar derivations; augmented unipolar and precordial derivations. Interpretation of the waveforms in different derivations. Calculation of the mean cardiac vector and ventricular axis.

Renal System

ANALYSIS OF THE RENAL FUNCTION

Functional anatomy of the kidney. The nephron. Mechanisms of urine formation. Renal clearance. Measurement of glomerular filtration rate and renal plasma flow. Filtration fraction.

ULTRAFILTRATION PROCESS

Structure of the renal glomerulus. Forces involved in filtration. Composition of the ultrafiltrate. Determination of the filtered load.

TUBULAR FUNCTIONS

Mechanisms of reabsorption and secretion in the nephron. Mechanism of salt and water reabsorption in the nephron. Regulation of the resorption of sodium chloride and water.

CONCENTRATION AND DILUTION OF URINE

Fluid compartments of the body. Osmolality of the body fluids. Osmolality in the cortex and medulla of the kidney. Mechanism of concentration and dilution of urine. Antidiuretic hormone.

Respiratory Function

PULMONARY VENTILATION

Functional anatomy of the respiratory system. Functions of the respiratory tract. Respiratory muscles and their innervation. Inspiration. Functional significance of the costal and diaphragmatic mechanisms. Expiration. Dead space. Pulmonary ventilation and alveolar ventilation.

RESPIRATORY MECHANICS

Alveolar pressure and air flow during the respiratory cycle. Pleural pressure and its variations during the respiratory cycle. Pressure-volume relationships of the lung, chest and chest-lung system. Pulmonary compliance. Contribution of surface forces to the lung elasticity. Pulmonary surfactant and its physiological significance.

SPIROMETRY (Laboratory Prracticals)

Direct and indirect spirometry: measurement of lung volumes and capacities.

PULMONARU GAS EXCHANGE

Composition of atmospheric and alveolar air. Structure of the alveolar-capillary barrier. Gas partial pressures in the alveoli and alveolar capillaries. Diffusion of gases through the alveolar-capillary membrane. Volume of oxygen and carbon dioxide exchanged per unit of time.

OXYGEN TRANSPORT 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. Interaction between the transport of oxygen and carbon dioxide (Bohr effect).

TRANSPORT OF CARBON DIOXIDE IN THE BLOOD

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 oxygen and carbon dioxide (Haldane effect).

NERVOUS AND CHEMICAL REGULATION OF RESPIRATION

Control of breathing by mrdullary and pontine respiratory centers. Lung receptors and respiratory reflexes. Ventilatory responses to changes in arterial partial pressure of oxigen and carbon dioxide and concentration of hydrogen ions. Function of peripheral and central chemoreceptors in the

Readings/Bibliography

R.M. Berne, M.N. Levy, FISIOLOGIA (a cura di, B.R. Koeppen, B.A. Stanton), Sesta Edizione, Milano Casa Editrice Ambrosiana, 2010.

Alternatively the English version of the same textbook :Berne & Levy Physiology, (B.M. Koeppen and B.A. Stanton, Editors) sixth revised edition, New York, Grune and Stratton Inc. 2010.

Berne & Levy Physiology, (B.M. Koeppen and B.A. Stanton, Editors) sixth revised edition, Philadelphia, Mosby Elsevier, 2010.)

Teaching methods

Lectures, that will cover the program of the course, and practical laboratories, where students will have the possibility to practice recording of cardiovascular and respiratory variable in humans.

Assessment methods

Students must sit an oral exam consisting in three questions aimed at ascertaining students' understanding of the topics presented during the course lectures and laboratories. Students will be questioned by different examiners and must reach a minimum score of 18/30 for each question in order to pass the exam.

Teaching tools

Teaching tools used for lectures: Video projector, PC, overhead projector, laboratories for the assessment of the cardiovascular and respiratory functions.

Office hours

See the website of Elisabetta Ciani

See the website of Sandra Guidi

See the website of Stefania Trazzi