THE CELL: FUNCTIONS AND REGULATIONS

Module Cellular physiology

THE CELL AS AN INTEGRATED SYSTEM

·       Dynamic balance, cell functions, the cell as a thermodynamic system, energy and entropy, the cell as a chemical system.

·       Gas and solute exchanges through cell membranes (Fick's law, passive diffusion, facilitated diffusion, controlled diffusion, primary and secondary active transport).

·       Homeostasis, steady state, regulation of cellular functions.

GAS LAWS AND THEIR APPLICATIONS

·       Ideal gas law, Boyle's law, Charles and Gay-Lussac’s law, second law of Gay-Lussac, Avogadro's law, Dalton's law, Graham's Law, Henry's Law, Laplace’s law. Applications in physiology and pathophysiology (physiological polycythemia, high-altitude sickness, decompression sickness).

FLUID COMPARTEMENTS AND HOMEOSTASIS

·       Human body fluid compartments: intracellular and extracellular compartments, compartments volumes and methods for their measurements. Sources and removal of body fluids. Water and salts balance.

·       Exchanges of water and electrolytes through biological membranes. Concentration and electrochemical gradients. Saline, isotonic and iso-osmotic solutions, and their use. Osmotic pressure: definition, units of measurements, plasma values. Van't Hoff’s law, Gibbs-Donnan equilibrium. Hydrostatic pressure. Colloid osmotic and oncotic pressure: plasmas value and fluctuations. Consequences of oncotic pressure modifications. Starling's law and capillary exchanges. Pathophysiology: edema.

PRINCIPLES OF HEMODYNAMICS AND HEMORHEOLOGY 

·       Systemic circulation: generalities. Blood volume and velocity in different areas of the vascular system. Morphological and physiological characteristics of vessels: arteries, capillaries and veins.

·       Blood flow: physical factors affecting blood flow. Bernoulli’s principle. Pressure, flow and resistance: Hagen-Poiseuille Law. Blood viscosity: relationship between viscosity and haematocrit. Turbulent blood flow. Laplace's law applied to vessels.

·       Vascular tone: nervous, hormonal and humoral control.

ION CHANNELS AND MEMBRANE POTENTIAL 

·       Cell excitability: cell membrane polarization, depolarisation and hyperpolarization.  Ion channels: voltage-gated ion channels for sodium, potassium, calcium, chloride  (characteristics, functions, main agonist and antagonists), electrophysiological techniques (patch clamp), Pathophysiology: canalopathies.

·       Electric potentials: membrane potential, electrochemical potential, Nernst equation, Goldman equation. Genesis and characteristics of an action potential. All-or-none law. Refractory period. Membrane repolarization. Graded potentials.

·       Excitability conduction along cell membranes. Propagation velocity. Saltatory or continuous conduction, myelin sheath.

SYNAPTIC TRANSMISSION 

·       Excitable cells communication. Electric and chemical synapses. Synaptic types. 

·       Neurotransmitters and neuropeptides: synthesis, transport, release and secretion, neurotransmitter release cycle, vesicle cycle (trafficking). 

·       Neuromuscular junction. Endplate potential, miniature potential, quantal neurotransmitter release. 

·       Synaptic integration and transmission in CNS (EPSP, IPSP, spatial and temporal summation). 

·       Ionotropic and metabotropic receptors.

·       Synaptic plasticity, Hebbian theory, long-term and short-term plasticity (long-term potentiation e long-term depression).

NEUROTRANSMITTERS AND RECEPTORS

·       Acetylcholine, nicotinic receptors, muscarinic receptors, cholinergic synapses, main agonists and antagonists, pathophysiology: Miastenia gravis

·       Glutamate glutamine cycle, NMDA, AMPA and Kainate receptors, metabotropic receptors, involvement in synaptic plasticity (LTP), main agonists and antagonists, Pathophysiology: glutamate excitotoxicity, notes on related diseases (Alzheimer’s disease, glutamate hypothesis of schizophrenia). 

·       GABA, Ionotropic and metabotropic receptors, Notes on benzodiazepine, barbiturate and alcohol mechanism of action.Pathophysiology: anxiety, Epilepsy.  

·       Catecholamine and their receptors, Role in SNA, Notes on stress and catecholamine

·       Dopamine and its receptors. Pathophysiology: Addiction, Parkinson’s disease, Schizophrenia 

·       Serotonin and its receptors, Drugs acting on serotonin receptors. Pathophysiology: mood disorders.

·       Endocannabinoids and opioids, notes on drug abuse (cocaine, amphetamine, heroine, hallucinogens, etc.) 

·       Nitric oxide pathway and retrograde transmission

MUSCLE CONTRACTION 

·       Skeletal muscles: structure, myofibrils, sarcomere and mechanisms of contraction, Sliding filament theory of muscle contraction, Neuromuscular junction, Excitation-Contraction Coupling, single muscle twitch and tetanus, isometric and isotonic contraction, length-tension curve, force-velocity curve, muscle energetics, oxygen consumption, muscle work, performance, and fatigue. Muscle fibers. Skeletal muscle innervation. Electromyogram.

·       Smooth muscle: generalities, unitary and multiunit muscles, structure, contraction mechanisms, contraction regulation (arteriolar tone), biomechanics. 

·       Cardiac muscle: generalities, structure, contraction mechanisms, contraction regulation, biomechanics.

NERVOUS SYSTEM: GENERALITIES 

·       Neuron: morphologic, functional, biochemical and trophic unit of the nervous system

·       Glia functions