THE RESPIRATORY SYSTEM

1. THE RESPIRATORY SYSTEM DR. MARWA SHAALAN PHARM-D

2. The Respiratory System • Basic functions of the respiratory system • Breathing (Pulmonary Ventilation) – movement of air in and out of the lungs • Inhalation (inspiration) draws gases into the lungs. • Exhalation (expiration) forces gases out of the lungs. • Gas Conditioning – as gases pass through the nasal cavity and paransal sinuses, inhaled air becomes turbulent. The gases in the air are • warmed to body temperature • humidified • cleaned of particulate matter • Gas Exchange - respiration • Supplies body with oxygen • Disposes of carbon dioxide • Produces Sounds • Protects respiratory surfaces • Site for olfactory sensation

3. Respiration • Respiration – four distinct processes must happen • Pulmonary ventilation – moving air into and out of the lungs • External respiration – gas exchange between the lungs and the blood • Transport – transport of oxygen and carbon dioxide between the lungs and tissues • Internal respiration – gas exchange between systemic blood vessels and tissues

4. Functional Anatomy of the Respiratory System • Respiratory organs • Nose, nasal cavity, and paranasal sinuses • Pharynx, larynx, and trachea • Bronchi and smaller branches • Lungs and alveoli

5. Organs of the Respiratory System Figure 21.1

6. Respiratory System • Consists of • Respiratory muscles – diaphragm and other muscles that promote ventilation • Respiratory zone – site of external respiration – respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.

7. Features Of Alveoli • Alveoli cell types • Type I cells site of gas exchangeand • Type II cells - secrete surfactant • Macrophages Figure 21.10b

8. Bronchial Asthma RESPIRATORY DISORDERS

9. BRONCHIAL ASTHMA

17. X- RAY IN ASTHMA

20. TRIALS

30. If it necessary – hospitalization with i/v infusion of • glucocorticosteroids and euphyllin

31. TREATMENT OF COUGH

32. TREATMENT OF COUGH • Cough is a useful physiological mechanism that serves to clear the respiratory passages of foreign material and excess secretions. • It should not be suppressed indiscriminately. • There are, however, many situations in which cough does not serve any useful purpose but may, instead only annoy the patient or prevent rest and sleep.

33. TREATMENT OF COUGH • Chronic cough can contribribute to fatigue, especially in elderly patients, in such situations the physicians should use a drug that will reduce the frequency or intensity شده of the coughing. • Cough reflex is complex, involving the central and peripheral nervous systems as well as the smooth muscle of the bronchial tree.

34. TREATMENT OF COUGH • It has been suggested that irritation of the bronchial mucosa causes bronchoconstriction, which in turn, stimulates cough receptors( which probably represent a specialized type of stretch receptor) located in the tracheobronchial passages.

35. TREATMENT OF COUGH • Afferent conduction from these receptors is via fibers in the vagus nerve; central components of the reflex probably involve several mechanisms or centres that are distinct from the mechanisms involved in the regulation of respiration.

36. TREATMENT OF COUGH • The drugs that directly or indirectly can affect this complex mechanism are diverse. -For example , cough may be the first or only symptom in bronchial asthma or allergy, and in such cases bronchodilators(e.g., 2 – adrenergic receptor agonists have been shown to reduce cough ) without having any significant central effects, other drugs act primarily on the central or the peripheral nervous system components of the cough reflex.

37. COUGH Forceful release of air from lungs Sudden, often involuntary (protective) reflex and major defensive mechanism Cont…..

38. Causes of cough : • Expulsion of respiratory secretion or foreign particles or irritant or excessive mucus from air passages • Symptom an underlying respiratory and/or cardiovascular pathology

39. Types of cough • Acute cough =lasting<3 weeks • Chronic cough =lasing >8 weeks Cough may be i) Un productive (dry) cough OR ii) Productive cough (sputum) cont.

40. Most common causes of cough • Common cold, • Upper/lower respiratory tract infection • Allergic rhinitis • Smoking • Chronic bronchitis • Pulmonary tuberculosis • Asthma • Gastroesophageal reflux • Pneumonia • Congestive heart failure • Bronchiectasis • Use of drugs (e.g., Angiotensin-converting enzyme inhibitors)

41. Treatment of Cough 1) Antitussives (cough centre suppressants) 2) Expectorants (Mucokinetics) 3) Mucolytics 4) Antihistamines 5) Bronchodilators 6) Pharyngeal Demulcents

42. 1) Antitussives (cough centre suppressants) Drugs suppress cough & produces symptomatic relief MOA Mainly suppress cough centre in medulla (both central & peripheral effects) E.g., Opoid drugs (codeine, pholcodeine, noscapine, dextromethorphan) Opioid = most effective for cough

43. i) Codeine • Codeine= prodrug  metabolized to morphine • It is an alkaloid found in Opium poppy plant • Has less addiction • resp. centre depressant ↓ • Has useful antitussive action at low doses (<15 mg) • Produce drowsiness, thickening of sputum & constipation

44. ii) Noscapine & Pholcodeine • Related to papaverine • Do not have addictive, analgesic & constipating properties • Do not interfere with mucocilliary movement • Noscapine (15 mg) & pholcodeine (10 mg)=syrup

45. iii) Dextromethorphan Available in syrup, tablets, spray forms MOA NMDA receptor antagonist Uses Cough suppressant, temporary relief of cough caused by minor throat & bronchial irritation (accompanies with flu & cold), pain relief Ad Effects= Nausea, vomiting, drowsiness, dizziness, blurred vision

46. 2) Expectorants (Mucokinetics) • Act peripherally • Increase bronchial secretion OR • Decrease its viscosity  facilitates its removal by coughing • Loose cough ►less tiring & more productive Cont….

47. Classification of Expectorants Classified into b) Directly acting E.g., Guaifenesin (glyceryl guaiacolate), Na+ & K+ citrate or acetate, b) Reflexly acting E.g., Ammonium salt

48. i) Sodium & potassium citrate or Acetate • They act directly Actions: ▲Bronchial secretion by salt action ii) Guaifenesin • Expectorant drug usually taken by mouth • Available as single & also in combination MOA=Increase the volume & reduce the viscosity of secretion in trachea & bronchi

49. iii) Reflexly acting Ammonium salts Gastric irritants reflexly  bronchial secretions + sweating

50. 3) Mucolytics Help in expectoration by liquefy the viscous tracheobronchial secretions E.g., Bromhexine, Acetyl cysteine, i) Bromhexine Synthetic derivative of vasicine(alkaloid= Adhatoda vasica) Cont….