Respiratory system-2

Respiratory System- I Dr Hafsa NiaziWhat is Respiratory System • A system consisting of lungs and air passages specialized for the intake of oxygen and exchange of gases with the blood. • Respiration: The exchange of oxygen and carbon dioxide between the atmosphere and the cells of the body. • Respiration includes three things: 1) Pulmonary ventilation (inspiration and expiration) 2) External respiration (the exchange of gases between lungs and blood) and Internal respiration (between blood and tissues) 3) The use of oxygen in cellular metabolism.Functions • Respiratory Functions 1. Pulmonary ventilation 2. Diffusion of O2 and CO2 b/w alveoli and blood 3. Transport of O2 and CO2 to and from tissues 4. Regulation of O2 and CO2 in blood and tissue Diffusion is the passive movement of particles (atoms, molecules, or ions) from an area of higher concentration to an area of lower concentration, without requiring external energy• Non Respiratory Functions 1 Air filtration (Respiratory system removes dust at the enterence of nose through mucus, nasal hair) 2 Protective/Cleansing Reflexes (SSC reflexes) Cough Reflex Triggered when dust, smoke, mucus, or other irritants enter the trachea or bronchi A forceful exhalation, which expels the irritant from the airways. Sneeze Reflex Triggered by irritation of the nasal mucosa (e.g., dust, pollen, pepper).A sudden forceful expulsion of air through the nose and mouth removes the irritant. Swallowing Reflex During swallowing, the epiglottis (elastic cartilage)closes the opening of the larynx (glottis) to prevent food and liquids from entering the trachea and lungs.• Olfaction ( detect odor, harmful substance such as gas leak, smoke, toxic chemicals) Olfactory nerve is responsible for smell • Vocalization (air passes through larynx vocal cord vibrate and produce sound) • Defense mechanism (Lungs protect from harmful particles through mucus, cilia that is tiny hair like structure helps mucus to move, alveolar macrophage helps to engulf bacteria and foreign particles) • Maintenance of water & Regulation of body temperature( As air passes through airways, it is warmed and humidified before reaching lungs. During exhalation, lungs lose small amount of water vapor and heat to regulate body temp and water) • Regulation of PH (Lungs maintain acid base balance by controlling amount of CO2 in blood) • Secretion of ACE (lungs also act as a endocrine organ by producing Angiotensin converting enzyme that helps regulate BP)Respiratory Division Respiratory tract •Upper Respiratory Tract (URT): consists of nose, pharynx, and larynx. •Lower Respiratory Tract (LRT): consists of Trachea, Bronchi, bronchioles and lungs. Pharynx: Is a muscular tube extending About 13 cm (5 inch). It is divided into three regions: Upper Respiratory Tract (URT)Regions of Pharynx Nasopharynx -- Lies dorsal to the soft palate. -- Receives the eustachian (auditory) tubes. -- Houses pharyngeal tonsils(mass of lymphoid tissue provide immunity)• Oropharynx -- The space between the soft palate and root of the tongue which extends inferiorly to the hyoid bone. Means it extends from the Uvula to the level of the hyoid bone. -- It contains palatine(on the either side of oropharynx) and lingual tonsils (base of tongue).UVULA• Laryngopharynx It extends from the hyoid bone to the cricoid cartilage. • Oropharynx and laryngopharynx serve as a common passageway for both food and air.