Respiratory system 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 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+ ) - -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, Non-chemical influences More types of receptors in respiratory system Irritants receptors on mucose of respiratory system – quickly adaptated, Stimulus: chemical substances (histamin, serotonin, cigarette smoke). Respons: increase mucus secretion, constriction of larynx and brochus C-receptors (=J receptors)– free nerve ending of n.vagus (type C) in intersticium of bronchus and alveolus; Mechanical irritans (pulmonary hypertension, pulmonary oedema) Response: hypopnoe, bronchoconstriction, cough Stretch receptors slowly adaptation, in smooth muscle trachea and bronchus; its irritants triggered decrese activity of respiratory centre – Hering-Breuer´s reflexes. • F:\FRVŠ\FILM FOTO FINAL\001.jpg • • 11 • Upraveno dle: Poopesko Peter a kol. (1990) • • 12 • • • TRACHEA N. VAGUS A. CAROTIS ENDOTRACHEAL CANNULA • • 13 HERING-BREUER REFLEX HB před vagotomií001 • REFLEX STOP BREATHING • ARTEFAKTS • ARTEFAKTS • • 14 VAGOTOMY klidové dých po vagotomii004 • • • • One-side VAGOTOMY Both-side VAGOTOMY inspirium exspirium 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 Periodic breathing •Non regulary, non rhythmic, respirátory coming in „periods“ e.g. – period with respiration folows period without respiration. • •CHEYNE-STOKES – e.g. sleeping babies •BIOT‘S – brain injury, encephalitis •„gasping“ – newborn •KUSSMAUL – during coma in diabetic patients (ketoacidosis) 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) 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. Travelling by aircraft (On board aicraft is pressure as on 2000 m above see level) High risk for patients with: - concentration of hemoglobin lower than 60 % - severe step of atherosclerosis - cardial insuficiency - Respiratory insuficiency - non-treated hypertension (BP ower 200/100mmHg) Toxicity of oxygen The toxicity seems to be due to the production of the superoxid anion and H2O2 + increase pCO2 in body (all hemoglobin is bound with oxygen) Symptoms are dependent on time of exposure: Exposure – 8 hours:- respiratory passages became irritated - Substernal distress - Nasal congestion - Sore throat - Cough - 24-48 hours: - damage of lungs – decrease production of surfactant Recommendation: 100 % - give discontinuosly + together with air HYPERVENTILATION • •Definition: Both, accelerated and deep breathing •In humans, hyperventilation coming as combination of anxiety and pain •During hyperventilation is expired CO2 (hypocapnia) and the increase of pO2 (hyperoxia) -------------- vasoconstriction of cerebral vessels • •Symptoms: tingling in the ears, feeling light in the head, headache etc. • •Removing symptoms - by increasing pCO2 in the body – e.g.: by breathing into and out of the bag (re-breathing) •