FUNCTIONAL ANATOMY OF RESPIRATORY SYSTEM.pptx

functional anatomy of respiratory system

1. FUNCTIONAL ANATOMY OF RESPIRATORY SYSTEM BY SHAMA PHYSIOLOGY TUTOR

2. RESPIRATION Extract oxygen from atmosphere to deliver it to tissues and take out carbon dioxide from tissues and discharge it in atmosphere. 2 types of respiration: external and internal respiration. STAGES OF RESPIRATION: : Ventilation stage, transport stage, exchange stage and tissue stage It consists of chest wall, respiratory muscles which increase and decrease the size of thoracic cavity.

3. Components of respiratory systems System starts with nose and ends in the terminal alveoli. 2 parts: URT and LRT URT includes, sinuses, glottis, pharynx and larynx. Its gets humidified and it attains body temperature by the time it reaches trachea LRT includes trachea, airways and alveoli. Bifurcates into mainstem bronchi that enters the lungs.

4. Trachea branches into 2 bronchi, further branches into smaller bronchioles called tracheobronchial tree. Between trachea and alveolar sac, the airways divide 23 times. First 16 generations of passages form conducting zone of airways. Last 7 generations of airways form respiratory zone is the site for gas exchange. these multiple divisions greatly increase the total cross sectional area of the airways from 2.5 sq. cm in the trachea to 11,800 sq. cm in the alveoli.

5. Conducting zone Warm and humidify inspired air. Distribute air evenly. Nonspecific defense system. Cartilage is present in First four generation that prevents collapse of these airways. Elasticity of lung tissue maintains their patency as they are suspended by elastic tissue of lung parenchyma. No exchange of gases so called it as anatomic dead space

6. BLOOD SUPPLY OF CONDUCTING ZONE Receive blood from bronchial circulation by bronchial artery originates from descending aorta and drained by pulmonary veins. NERVE SUPPLY Innervated by autonomic nervous system. Muscarinic receptors are abundant and cholinergic discharge cause Bronchoconstriction by vagal stimulation. Trachea and bronchi have cartilage in their walls but relatively little smooth muscle. they are lined by ciliated epithelium that contains mucous and serous Glands also contains β 2 adrenergic receptors stimulate sympathetic tone that causes Bronchodilation. Activation of this receptor also increases bronchial secretion and α receptor inhibits secretion

7. Respiratory zone Last seven generation of airway form this zone. (site for gas exchange). Bronchioles from 17 th to 19 th generations called respiratory bronchioles. Generations 20-22 are the alveolar ducts that finally terminate in alveolar sac (generation 23). 300 million of alveoli present. TSA of alveoli is between 50 sq m and 100 sq m Its epithelium is lined by epithelial cells that are of 2 types: type I and typeII Type I epithelial cells are p[resent in more numbers and cover 95% of epithelial surface of alveoli. Type II secrete surfactant and play important role in alveolar repair. Alveoli also contain pulmonary alveolar macrophages (PAMs) that causes phagocytosis

8. Blood supply of respiratory zone Receive blood from pulmonary circulation. The lungs have extensive capillary network that occupies about 80% of alveolar surface area. This helps in easy diffusion of gases along the alveolocapillary membrane.

9. LUNGS 2 lungs divided into many lobes Covered by pleura. There are 2 layers of pleura: parietal and visceral pleura. Parietal pleura produces pleural fluid which is ultrafiltrate of plasma. It facilitates the change in size and shape of lungs during respiration. Protects lungs. 3 lobes in right lung and 2 lobes in left lung

10. Functions of respiratory system Respiratory function Gas exchange Regulation of blood pH by controlling carbon dioxide output from body Non- respiratory functions Filtering small emboli from blood Left ventricular reservoir Biochemical functions Olfactory function Warming and moisturizing inhaled air ACE secreted by epithelium of pulmonary blood vessels Defense functions (PAMs, PGE2, immunoglobulins. Surfactant synthesis

11. Phonation by larynx coz its acts as a vibrator Route for administration of anesthesia. Local fibrinolytic system

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