12939 - Cellular Physiology

Academic Year 2021/2022

  • Docente: Sandra Guidi
  • Credits: 6
  • SSD: BIO/09
  • Language: Italian
  • Teaching Mode: Traditional lectures
  • Campus: Ravenna
  • Corso: Single cycle degree programme (LMCU) in Medicine and Surgery (cod. 5708)

Learning outcomes

At the end of the course, the student will know the basic functional mechanisms of nervous, muscular, epithelial, endocrine cells of the human body

Course contents

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.

Readings/Bibliography

R.M. Berne, M.N. Levy, FISIOLOGIA (a cura di, B.R. Koeppen, B.A. Stanton), 7a Edizione, Casa Editrice Ambrosiana, 2018 (ISBN 8808480046).

Berne & Levy Physiology, (B.M. Koeppen and B.A. Stanton, Editors) 7th edition, Elsevier, 2017 (ISBN: 0323393942).

Teaching methods

Lectures, covering the whole Course Program.

Assessment methods

The entire Physiology Course consists of three parts. The first (Cellular Physiology) is held during the first semester, the second (Apparatus Physiology) and the third (Applied Physiology) are held during the second semester. The exam is unique and is held at the end of the second semester, but the student can take a mid-term written test with alternate-choice questions at the end of the Cellular Physiology Course. The mid-term test includes 44 questions. The final score of the test is given by the algebraic sum of the score of the correct answers (1 point), of the wrong answers (-0.6 points) and of answers not given (0 points), converted into thirtieths. The mid-term test is considered sufficient with a score of 18/30. Students who accept the grade of the mid-term test take the final oral exam only on the parts relating to the Physiology of Apparatus and Applied Physiology. During the oral exam the student is questioned on topics drawn randomly with a balanced procedure (two questions regarding Apparatus Physiology and Applied Physiology, a third question on Cellular Physiology if the mid-term test has not been taken) by different teachers for each topic covered. If the answer is considered sufficient, each question is evaluated with a variable score between 18/30 and 30/30 with honors. The achievement by the student of a coherent vision of the topics discussed in the exam combined with their critical use, the demonstration of an expressive mastery and ability to use specific biomedical language terms are evaluated with marks of excellence. The mostly mechanical and / or mnemonic knowledge of the subject, the ability of synthesis and analysis not completely articulated, and / or the use of a correct but not always appropriate language lead to intermediate-grade evaluations; training gaps and / or inappropriate language in a context of basic yet complete knowledge of the exam material lead to marks that do not exceed sufficiency. Training and significant knowledge gaps concerning the teaching materials offered during the course and inappropriate language are negatively evaluated. Each of the three questions weighs one third in the calculation of the final grade. Insufficient evaluation of the answer to even one of the three questions renders the test insufficient.

Teaching tools

Digital Video projector, PC.

Office hours

See the website of Sandra Guidi

SDGs

Good health and well-being

This teaching activity contributes to the achievement of the Sustainable Development Goals of the UN 2030 Agenda.