MedInTO Medicine and Surgery

Physiological basis of human body

Physiological basis of human body

Academic year 2019/2020

Sommario del corso

• Course objectives
• Results of learning outcomes
• Course delivery
• Learning assessment methods
• Support activities
• Program
• Suggested textbooks and readings
• Teaching tools

Course objectives

Introducing the basic principles underlying the functions of the human body. Completing the knowledge of cell biology and biophysics by teaching the mechanisms of electrical signaling and synaptic transmission. Teaching the principles of sensory systems and of the main sensory organs. Teaching the mechanisms of muscle contraction.

Results of learning outcomes

Understanding of the basic design of the integrated functions of the human body, derived from the concepts of internal environment and homeostasis. Knowledge of the cellular mechanisms of electrical signaling and synaptic transmission. Understanding of the basic principles of sensory systems. Knowledge of the physiology of the main sensory organs. Knowledge of the mechanisms of muscle contraction.

Course delivery

Formal class (lesson) and interactive learning.

Learning assessment methods

Quiz followed by oral examination. In June and July 2020 the exams will oral only, via WebEx. The students will receive and email with the WebEx link the day before the exam. Since September 2020 the exam will again consist of a written test followed by an oral.

Support activities

Interactive learning in the afternoon sessions.

Program

Basic principles underlying the functions of the human body.

Internal environment and homeostasis. Mechanisms of homeostasis: control systems, negative and positive feedback, feedforward. Local control. Reflex control: elements and properties of reflexes. Biological rhythms.

Movement of molecules across cell membranes. Passive processes: diffusion, permeability, flow through ion channels. Ion channels: permeation, selectivity, gating, inactivation, modulation, classification. Patch-clamp and single channel current. Processes mediated by a membrane carrier: facilitated diffusion, primary and secondary active transport. Principles of transport across epithelia.

Physiology of the neuron.

Axonal transport. Physiological functions of glia: astrocytes, oligodendrocytes, Schwann cells, microglia, radial glia, neuroepithelial stem cells. Cerebrospinal fluid. Blood brain barrier.

Biophysics of excitable membranes. Diffusion potential. Equilibrium potential and Nernst law. Goldman equation. Role of Na⁺/K⁺ pump to maintain ionic gradients. Resting potential. Action potential: ionic currents, membrane permeability, single channel currents, all-or-none law, refractory period. Passive electrophysiology and electrotonic propagation: effects of electrical currents on the membrane; time and space constants. Action potential conduction along unmyelinated fibers: relationship between diameter, space and time constant and conduction velocity. Saltatory conduction in myelinated fibers. Conduction velocity and nerve fibers classifications.

Synaptic transmission.

Electrical synapse. Presynaptic mechanisms in the chemical synapse: role of Ca²⁺, miniature endplate potentials, molecular mechanisms of neurotransmitter release, synaptic vesicles cycle. Neurotransmitters: synthesis, storing in vesicles, release, removal by diffusion, reuptake, inactivation. Functional differences between small molecule neurotransmitters and neuropeptides. Diffuse projection systems. Postysnaptic mechanisms: reversal potential and ionic mechanism of endplate potential and of central excitatory and inhibitory postsynaptic potentials. Synaptic signal integration: temporal and spatial summation. Short and long-term synaptic plasticity. Neurotransmitter receptors: receptor channels and G-protein coupled receptors.

Physiology of muscle

Mechanism of muscular contraction. Sliding filament theory. Cross-bridge cycle.

Skeletal muscle: excitation-contraction coupling, muscle twitch, summation, tetanus, isometric and isotonic contraction, force-length and velocity-load curves, lengthening contraction, mechanical power, energetics, muscular fatigue, heat production, efficiency, subtypes of skeletal muscle fibers, control of force generation in the whole muscle, motor units recruitment and firing frequency.

Smooth muscle: single unit and multi unit muscle. Contraction mechanism. Excitation-contraction coupling and regulation of contraction. Cross-bridge cycle and latch-bridge mechanism. Control and modulation mechanisms.

The autonomic nervous system

Sympathetic and parasympathetic divisions. Preganglionic neurons. Synaptic receptors and functions of the autonomic nervous system. Function of the adrenal medulla. Sympathetic mass discharge. Stress response of the sympathetic nervous system. Central control of the autonomic nervous system.

General physiology of sensory systems

Sensory receptors. Adequate stimulus, sensory transduction, threshold, receptor potential. Action potential coding of stimulus intensity. Physiological and psychophysical response to stimulus strength. Receptive field. Acuity, two point discrimination threshold. Sensory adaptation. Sensory modality and quality of sensation.

Physiology of sensory organs: the somatic sensory system

Dorsal column and medial lemniscal systems. Cutaneous receptors: functional properties, adaptation, sensitivity, acuity, ion channels involved in mechanical transduction. Haptics and stereognosis. Thermoception: temperature range of the ion channels involved in transduction. Pain: nociceptors, first and second pain, ion channels of transduction, sodium channels for conduction of pain signals. Hyperalgesia, peripheral and central sensitization, allodynia, neuropathic pain, phantom limb. Physiological mechanisms of anaelgesia: gate control, placebo effect, descending pain control. Other somatosensory modalities.

Physiology of the eye

Pupillary light reflex. Optic properties of the eye: reflective surfaces, reduced eye, accommodation. Aqueous humor. Functions of the pigment epithelium: light reflection, removal of photoreceptor discs, the retinoid cycle. Phototransduction and adaptation to light/dark. Sensitivity, velocity and acuity of rods and cones systems. Visual pigments for color vision. Receptive field of on-center and off-center ganglion cells, detection of luminosity contrast, effect of background illumination.

Physiology of the ear

Properties of sound: frequency, pressure level, phase, waveform. Fourier transform. Audible spectrum, threshold-frequency curve. Effects of the external ear on sound. Impedance adaptation in the middle ear. Air conduction and bone conduction of sound. Function of the basilar membrane: traveling waves and decomposition of sound frequencies. Tectorial membrane and deflection of cilia. Transduction in the hair cell: endolymph, tip links, mechanically gated potassium channels. Receptor potential: AC and DC components. Sound amplification and sharp tuning by outer hair cells. The audiogram.

Physiology of the chemical senses

Olfactory epithelium: olfactory receptors, supporting cell, basal stem cells, Bowman glands. Odor transduction. Olfactory bulb. Taste papillae, taste buds, taste cells. Categories of taste. Transduction of gustatory signals. Functions of the trigeminal chemosensory system.

Dale Purves, George J. Augustine, David Fitzpatrick, William C. Hall, Anthony-Samuel LaMantia, and Leonard E. White (editors).  Neuroscience (6th edition).  Oxford University Press.

John E. Hall.  Guyton and Hall Textbook of Medical Physiology (13th edition).  Elsevier.

Eric R. Kandel, James H. Schwartz, Thomas M. Jessell, Steven A. Siegelbaum and A. J. Hudspeth.  Principles of neural science (5th edition).  McGraw-Hill.

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