Fisiologia della nutrizione
Di cosa parla
- Homeostasis and Cardiovascular System: The document begins with Bernard's concept of homeostasis and details the cardiovascular system, including heart structure (atria, ventricles), systemic and pulmonary circulation, and capillary exchange.
- Historical Context of Circulation: It traces the understanding of circulation from ancient Greek ideas to Harvey's groundbreaking work, incorporating Leewenhoek's discovery of capillaries and Malpighi's renal glomerulus.
- Cellular Physiology: Key cellular mechanisms are explained, such as the resting membrane potential (due to K+, Na+, and negatively charged proteins), the Na-K pump's role in maintaining cell volume, and the generation of action potentials in nerve cells (depolarization, repolarization).
- Cardiac Electrophysiology and Contraction: The cardiac action potential in pacemaker cells (sinoatrial and atrioventricular nodes) and ventricular cells is described, emphasizing the role of Ca2+ in excitation-contraction coupling, troponin, tropomyosin, and the sarcoplasmic reticulum.
- Cardiac Cycle and Hemodynamics: The phases of the cardiac cycle (systole and diastole), blood pressure measurement (sphygmomanometer, Korotkoff sounds), cardiac output calculation, and the body's adaptation to physical activity are covered.
- Nervous and Hormonal Regulation: The autonomic nervous system's control over heart rate (parasympathetic bradycardia, sympathetic tachycardia) and the principles of arterial pressure (Windkessel effect, Bernoulli's principle) are discussed.
- Fluid Dynamics: The formation of interstitial fluid through capillary filtration, influenced by hydrostatic and oncotic pressures, and its return via the lymphatic system are explained.
- Respiratory System: The anatomy of the respiratory tract, mechanics of breathing (inspiration, expiration), lung volumes, and the principles of gas exchange (partial pressures, alveolar-capillary membrane, respiratory quotient) are detailed.
- Gas Transport: The transport of oxygen (bound to hemoglobin) and carbon dioxide (as bicarbonate, dissolved, carbamino-hemoglobin) in the blood, including the Hamburger shift, is analyzed.
- Digestive System Overview: The digestive process is outlined from oral cavity (salivary enzymes) to stomach (HCl, pepsin) and intestines (pancreatic enzymes, bile, absorption of nutrients), with an emphasis on hormonal regulation of secretions.
- Liver Metabolism: The liver's role in glucose, amino acid (urea cycle), and lipid (cholesterol) metabolism is highlighted, linking diet to physiological processes.
- Energy Balance and Diet: Concepts of energy expenditure (basal metabolism, physical activity, specific dynamic action), macronutrient distribution, and assessment tools like BMI are presented.
- Endocrine System: Hormonal regulation is a major focus, covering hormone classification (polypeptides, amino acid derivatives, steroids), synthesis, release, transport, and feedback mechanisms.
- Thyroid and Adrenal Glands: Specific endocrine glands like the thyroid (T3, T4, TSH, metabolism, growth, related pathologies) and adrenal glands (aldosterone, cortisol, sex hormones, stress response) are discussed in detail.