Gas exchange in air- and water-breathing animals. Adaptation of the circulatory and digestive systems in vertebrates. Kidney and extrarenal osmoregulatory organs in vertebrates. Adaptation of metabolism and thermoregulation in vertebrates.
Randall, Burggren, French: Fisiologia animale, Zanichelli (trad. IV Ed americana)
Hille, Wise, Anderson: Fisiologia animale, Zanichelli
Taglietti, Casella: Principi di Fisiologia e biofisica della cellula, La Goliardica Pavese s.r.l.
Knut Schmidt-Nielsen: Animal Physiology: Adaptation and Environment 5th Edition
Learning Objectives
Knolewdge acquired:
Adaptation of the physiological processes by individual species to the environment. Differences in the processes that regulate the functions of the vegetative and relational life in vertebrates.
Competence acquired:
Evaluation of the adaptative value of the physiological processes.
Skills acquired (at the end of the course):
Analysis and interpretation of the experimental data.
Prerequisites
Basic knowledge of general physiology and biochemistry.
Teaching Methods
Lectures
Type of Assessment
Oral exam
Course program
Introduction to the course.
Fundamental concepts of physiology: structure / function relationship, homeostasis, negative feedback, compliance and regulation. Geometric similarity. Allometric relationships, the relationship between mass and basal metabolism in mammals and birds.
Breathing.
Recall on the properties of gases: equation of state of gases. Air composition, equivalence between pressure measurement units. Variations of partial gas pressures with altitude. Water vapor content of the air. Gas in solution. Comparison between the solubility coefficient of oxygen and carbon dioxide. Diffusion of gases, Fick equation applied to gases. Factors that limit the exchange of gas through the external surface of an organism. Main types of respiratory organs. Functional requirements of the respiratory organs. Convective transport of gases. Alternation of convection and diffusion in higher organisms. Relationship between ventilation and circulation, properties of the main types of gas exchange. Chemical-physical properties of air and water. Partial pressure ratio of oxygen and carbon dioxide in air and water. Ratio of partial pressure of oxygen and carbon dioxide in the inhaled medium and in the blood. Structure and function of the gills. Ventilation in teleostes: active ventilation and dynamic ventilation. Bimodal breathing in an aquatic environment. Air-breathing fish, main types of accessory respiratory organs. Lungfish: role of gills and lungs. Breathing in amphibians, lung structure and lung ventilation mechanics, role of the various respiratory organs during development. Role of the skin in gas exchange in the various vertebrates. Respiratory system of reptiles. Anatomy of the respiratory system of birds, the function of the air sacs. Structure of the cross-exchange gas exchange windscreens. Comparison with the respiratory system of birds and mammals. Gas exchange in the egg of birds. The lung of mammals, relationship between body mass and lung volume. Relationship between degree of subdivision and area of the alveolar surface. Thickness of the honeycomb wall. Anatomical dead space. Lung volumes and capacity. Alveolar gas renewal. Surface for the exchange of gases in the lungs. Respiratory exchange ratio and respiratory quotient. Correction of the gas volume for temperature, pressure, humidity. Surfactant material and lung stability. Pulmonary surfactant function. Breath control: trunk-brain mechanisms that generate the respiratory rhythm. Chemoceptive control of respiration. Response to hypercapnia. Regulation of gas exchange and respiration. Transport of oxygen and carbon dioxide in the blood. Structure and function of respiratory pigments. Oxyhemoglobin dissociation curve. Effect of temperature, pH (Bohr effect) and inorganic phosphates on the dissociation curve of oxyhemoglobin. Dissociation curve of fetal hemoglobin. Carbon monoxide dissociation curve. Root effect and swim bladder. Transport of carbon dioxide into the blood.
Circulation.
Components of the circulatory system. The heart as a pump. Cardiac muscle cells. Electrical activity of cardiomyocytes. Difference between myogenic and neurogenic hearts. Properties of pacemaker cells and their localization in vertebrates. Difference between cardiac and skeletal action potential. Slow response and fast response action potentials. Ionic basis of the rapid response action potential. Potassium currents. Sodium currents. Calcium currents. Ionic bases of slow response action potentials and pacemaker potential. Relationship between duration of action potential and heart rate. Nervous control of the potential pacemaker. The electrocardiogram. Relationship between electrocardiogram and action potential recordings. Coupling excitation contraction. Myocardial oxygenation in vertebrates. Relationship between heart mass and body mass in mammals and other vertebrates. Relationship between heart rate and body mass. Definition of cardiac output and systolic output. Cardiac output measurement. Effect of increased oxygen consumption on systolic range. Definition of cardiac contractility. Regulation of cardiac contraction, intrinsic and extrinsic. Variation of pressure volume diagrams. Calculation of the average aortic pressure. Structure of the venous and arterial vessels. Functions of the vascular endothelium. Relationship between vessel thickness and diameter, Laplace equation. Colloid-osmotic pressure and lymphatic system. Vertebrate circulation: water compartments. Circulatory systems: teleost fish and elasmobranchs. Arrangement of the circulatory system in some air-breathing fish. Circulatory system lung fish. Circulatory system of amphibians. Circulatory system of reptiles. The circulatory system of mammals and birds compared with that of other vertebrates.
Osmoregulation.
Osmoregulatory and osmoconform organisms. Aquatic environment: ionic composition of fresh water, sea water and brackish water. Air environment. Osmoregulation mechanisms. The action of the kidneys in osmotic regulation. Mandatory exchanges of ions and water. Composition of freshwater animal extracellular fluids. Osmoregulatory mechanisms in freshwater vertebrates. Osmoregulatory mechanisms in marine teleostes. Seawater isosmotic vertebrates. Water leaks in terrestrial environment. Extraarenal osmoregulatory organs in terrestrial vertebrates: salt gland. Mammal kidney anatomy. Structure and function of the nephron. Urine formation. Glomerular filtration, composition of the renal ultrafiltrate. Regulation of renal blood flow (RES) and glomerular filtration volume (VFR). Tubular reabsorption and secretion. Renal Clearence. Measurement of the glomerular filtration rate. Reabsorption of NaCl, solutes and water along the nephron. Proximal tubule. Henle's loop countercurrent multiplication mechanism. Distal tubule. Duct collector, and control of water reabsorption. Development of the renal papilla and maximum osmolarity of the urine. The kidney of the lower vertebrates. Control of the volume of extracellular fluid: regulation of renal excretion of NaCl. Renin-angiotensin system. The pH of the extracellular liquid: body swabs. Responses to acid-base alterations. Renal pH regulation. Simple acid-base imbalances. Excretion of nitrogen residues in relation to the habitat. Ammoniotelic animals. Ureotelic animals. Uricothelic animals.