•Respiratory system Anat dých sys Kiss • • termBronchiol s alveolyLidské tělo řasinky dýchacích cest astma v bronších dýchábí žebra Silbernagl dychani Hrudní košSilbernagl Bucket-handle and water-pump handle effects Graf změny intrapleur tlaku Graf změny objemu Graf změny plícního tlaku Obrzměny intrapleur tlaku Silbernagl •pulmonalis •parietalis •PLEURA povrchové napětí Silbernagl 4E53C6BF • • • • • • Hollow spherical organ > Výměna plynů v alveolu Silbernagl disociační křivka hemoglobinu TRANSPORT O2 •100% •50% ¯ temperature pH ¯pCO2 ¯ DPG temperature ¯ pH pCO2 DPG pO2 •25 •50 •75 •100 Regulation of breathing Control of ventilation •https://sleep.sharepoint.com/siteimages/Chapter%203.png •Breathing is an automatic process that takes place unconsciously. Automaticity of breathing comes from regular (rhythmic) activity of groups of neurons anatomically localized in the medulla and its vicinity. •They can be divided into three main groups: • •dorsal respiratory group – placed bilaterally on the dorsal side of the medulla oblongata, only inspiratory neurons, sending axons to motoneurons of inspiratory muscles (diaphragm, external intercostal muscles; their activation=inspiration, their relaxation=expiration; participates on inspiration at rest and forced inspiration • •ventral respiratory group - located on the ventrolateral part of the medulla oblongata, the upper part: neurons whose axons of motor neurons activate the main and auxiliary inspiratory muscles; the lower part: expiratory neurons which innervate expiratory muscles (internal intercostal muscles). Neurons in this group operate only during forced inspiration and forced expiration. • •Pontine respiratory group - pneumotaxic center - dorsally placed on top of the pont, contributes to the frequency and depth of breathing; affects the activity of respiratory neurons in the medulla oblongata. Chemical factors affecting the respiratory center: •Central chemoreceptors -on the front side of the medulla -sensitive only to increase of arterial pCO2 (by increasing H+ ) - - - -Notice: -central chemoreceptor are stimulated by other types of acidosis (lactate acidosis, ketoacidosis) •Peripheral chemoreceptors •– located in the aortic and carotid bodies •-primarily sensitive to decrease in arterial pO2, particularly to decrease of O2 under 10-13 kPa in the arterial blood. •They convey their sensory information to the medulla via the vagus nerve and glossopharyngeal nerve. • •Mechanism of action: Decreased ATP production in mitochondria leads to depolarization of receptors membrane and to excitation of chemoreceptor •http://www.medicine.mcgill.ca/physio/resp-web/sect8.htm, Modulation of respiratory output Major parameters for feedback control – classical gases:pO2, pCO2, pH In additin to these, the respiratory system receives input from two other major sources: 1. variety of stretch and chemical/irritant receptors that monitor the size of airways and the presence of noxious agentsreceptors in respiratory system 2. Higher CNS centers that modulate respiratory activity for the sake of nonrespiratory activities Irritants receptors on mucose of respiratory system – rapidly adapting Stimulus: agens - chemical substances (histamin, serotonin, prostaglandins, ammonia, cigarette smoke). Respons: increase mucus secretion, constriction of larynx and brochus C-fibre receptors (juxtacapillary=J receptors)– free nerve ending of n.vagus (unmyelinated axon) in intersticium of bronchus and alveolus; Stimulus: Mechanical irritans (pulmonary hypertension, pulmonary oedema)+chemical Response: hypopnoe, rapid shallow breathing, bronchoconstriction, cough Stretch receptors slowly adapting (mechanoreceptors in tracheobronchial tree that detect the changes in lung volume by sensing the stretch receptors of the airway wall), inform to brain about the lung volume to optimize respiratory; its irritants triggered decrese activity of respiratory centre – Hering-Breuer´s reflexes. (protecting the lungs from overinflation/deflation) Baroreceptors – suppresses activity of respiratory centre Irritants of proprioreceptors of muscles, tendons during active and pasive movements of limbs Influenced activity of respiratory neurons (increase minute ventilation during work load) Limbic system, hypothalamus – strong pain, emotion Tractus corticospinalis =cortex – activated RC during work load temperature • F:\FRVŠ\FILM FOTO FINAL\001.jpg • • •22 • •Upraveno dle: Poopesko Peter a kol. (1990) • • •23 • • • •TRACHEA •N. VAGUS •A. CAROTIS •ENDOTRACHEAL CANNULA • • •24 •HERING-BREUER REFLEX HB před vagotomií001 • REFLEX STOP BREATHING • ARTEFAKTS • ARTEFAKTS • • •25 •VAGOTOMY • klidové dých po vagotomii004 • • • • •One-side VAGOTOMY •Both-side VAGOTOMY •inspirium •exspirium Periodic breathing •It is not regular, rhythmic, but respiration occurs in periods ("a moment to breathe, take a moment to not breathe„) • •CHEYNE-STOKES •BIOT‘S •„gasping“ •KUSSMAUL Hypoxia, hypoxemia •Hypoxia is a general name for a lack of oxygen in the body or individual tissues. •Hypoxemia is lack of oxygen in arterial blood. •Complete lack of oxygen is known as anoxia. •The most common types of hypoxia: 1.Hypoxic - physiological: stay at higher altitudes, pathological: hypoventilation during lung or neuromuscular diseases 2.Transport (anemic) - reduced transport capacity of blood for oxygen (anemia, blood loss, CO poisoning) 3.Ischemic (stagnation) - restricted blood flow to tissue (heart failure, shock states, obstruction of an artery) 4.Histotoxic - cells are unable to utilize oxygen (cyanide poisoning - damage to the respiratory chain) OXYGEN FALL mmHg dry atmospheric air 159 humid atmospheric air 149 ideal alveolar gass 105 end-expiration air 105 arterial blood 77 cytoplasma – mitochondria 3-10 mixed venous blood 40 venous blood 20 S02401-002-f007 pO2 = 1 mmHg Hypercapnia • Hypercapnia - increase of concentration of carbon dioxide in the blood or in tissues that is caused by retention of CO2 in the body • possible causes: total alveolar hypoventilation (decreased respiration or extension of dead space) • mild hypercapnia (5 -7 kPa) causes stimulation of the respiratory center (therapeutic use: pneumoxid = mixture of oxygen + 2-5% CO2) • hypercapnia around 10 kPa - CO2 narcosis - respiratory depression (preceded by headache, confusion, disorientation, a feeling of breathlessness) •hypercapnia over 12 kPa - significant respiratory depression - coma and death. 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