ANATOMY AND PHYSIOLOGY OF RESPIRATORY SYSTEM.pptx

Anatomy and physiology of respiratory system basics. The structural and functional unit of life are called cells. The group of cells with similar structure and function constitute a tissue and similar group of tissues constitute an organ. Likewise, the similar functioning organs constutute the body system.

1. ANATOMY AND PHYSIOLOGY OF RESPIRATORY SYSTEM Understanding the Mechanics of Breathing Dr. Pratima Paudel B.A.M.S., M.S. (Ayu- Shalakya Tantra)

2. ORGANS OF RESPIRATION Respiratory system consists of organs which provide the pathway for supply of oxygen to the body and expulsion of carbon dioxide from the body to the surrounding atmosphere. 1) Nose 2) Paranasal sinuses 3) Nasopharynx 4) Larynx 5) Trachea and bronchi 6) Lungs 7) Respiratory muscles

3. DIVISION OF RESPIRATORY SYSTEM: 1) STRUCTURAL DIVISION:

4. 2) FUNCTIONAL DIVISION; Dead zone/ Conducting Zone: Corresponds to nose and the nasal cavity upto terminal bronchioles Volume of air-150ml Respiratory zone: corresponds to the lung parenchyma and includes the respiratory bronchioles, alveolar ducts, and alveoli. Volume of air-5-6L Trachea and the first 16 generations of tracheobronchial tree constitute the conducting zone . The last 7 generations of tracheobronchial tree constitute the respiratory zone.

5. NOSE AND PARANASAL SINUSES Functions: It is a part of the respiratory passages It has the olfactory function Parts 1) External nose 2) Nasal cavity 3) Medial wall or nasal septum 4) Lateral wall

6. 1) EXTERNAL NOSE Forms a pyramidal projection in the middle of the face. External nose is made up of cartilaginous framework supported by bones and is covered with skin.

7. 2) Nasal cavity It is pyramidal in shape. It extends from the nostrils (anterior nares) to the posterior nasal apertures (choanae). Parts i . Vestibule Dilated part at Anterior nasal opening ii. Olfactory region The upper one-third of nasal cavity has the olfactory receptor cells. iii. The respiratory region Lower two-third is lined by thick mucous membrane.

8. Boundaries of nose Each half of the nasal cavity has: a. Roof Formed by: cribriform plate of the ethmoid bone. Nasal bone and nasal part of frontal bone(anteriorly) Sphenoid bone (posteriorly) b. Floor - Formed by palate which separate the nasal cavity from oral cavity.

9. c. Medial wall or nasal septum - Osseocartilaginous partition between the two halves of the nasal cavity. The bony part: formed by vomer and perpendicular plate of ethmoid bone. The cartilaginous part: formed by septal cartilage and septal process of inferior cartilages. The cuticular part: formed by fibrofatty connective tissue covered by skin.

10. Blood supply Arterial supply: anterior ethmoidal artery(branch of ophthalmic artery) posterior ethmoidal artery superior labial branch of facial artery sphenopalatine artery greater palatine artery at antero-inferior quadrant, there is a rich anastomosis between the septal branches, the area is called the little's area or keisselbach's area-common site for epistaxis.

11. d. Lateral wall of nose It is irregular and owing to the presence of 3 shelf-like bony projections called conchae or turbinate. These elevations are called superior, middle and inferior conchae.

12. PARANASAL SINUSES These are air filled extensions of the respiratory part of nasal cavity in the skull bones. FRONTAL AIR SINUS: situated in the frontal bone. ETHMOIDAL AIR SINUS: There are 3 groups- anterior, middle and posterior MAXILLARY AIR SINUS: Largest among the air sinuses. SPHENOIDAL AIR SINUS:A cubical cavity within the body of sphenoid.

13. Functions of PNS: They reduce the weight of the skull The inhaled air is warmed and humidified They add resonance to the voice Filter the air inhaled

14. PHYSIOLOGY OF NOSE 1) Respiration: 2) Air-conditioning of inspired air: Air is efficiently filtered, humidified, adjusted to proper temperature and cleared of all the dust, bacteria and viruses by the nose. 3) Protection of airway: Enzymes and immunoglobulins: The are present in nasal secretions. Muramidase (lysozyme) kill bacteria and viruses. Immunoglobulins ( ig A and IgE ) and interferon provide immunity against upper respiratory tract infections. IL Sneezing: 4) Vocal resonance 5) Nasal reflexes: sneezing 6) Olfaction

15. PHARYNX 12-14cm long From the base of the skull to có level. lies behind nose, mouth and larynx. 1. Nasopharynx 2. Oropharynx 3. Laryngopharynx 1. Nasopharynx Behind the nose, from skull base to above the level of soft palate. Adenoids or pharyngeal tonsils are located in the posterior wall

16. The auditory tube connects the middle year to the pharynx. 2. Oropharynx Behind the oral cavity. Below the level of soft palate upto 3 cervical vertebrae.ie, from below the level of uvula upto hyoid bone. Palatine tonsils are present at the lateral wall. Lingual tonsils are present at the base of the tongue. 3. Laryngopharynx Also called hypopharynx From C3 to C6 level. From upper border of epiglottis to the lower border of cricoid cartilage. Common passage for food and air.

17. Functions of tonsils and adenoids 1. immunology and host defences 2. sentinels at the portal of aerodigestive tract. 3. Antibody production especially secretory IgA

18. LARYNX Also called 'voice box'. Serves as air passage. Extends from root of tongue up to trachea.ie from C3 toC6. CARTILAGES OF LARYNX UNPAIRED CARTILAGES 1. Thyroid cartilage 2. Cricoid cartilage 3. epiglottis PAIRED CARTILAGES 1. Arytenoid 2. Corniculate 3. Cuneiform

19. CAVITY OF LARYNX •Two pairs of folds projects in to the cavity from the lateral walls Upper pair of folds are vestibular folds or the false vocal cords and the fissure between them is called rima vestibuli The lower pair of folds are the true vocal cords and the fissure between them is the rima glottis Concerned with voice production.

20. Laryngeal muscles Intrinsic

21. TRACHEA Extends from lower border of cricoid cartilage (C6)as the continuation of the larynx and ends at the level of sternal angle. (T4&T5)

22. Lungs and Tracheobronchial tree Functions of lung and tracheobronchial tree Organ of exchange of gases. Surfactant secreted by pneumocytes 2 of alveoli prevents the collapse of eye. Non respiratory functions of lung - Angiotensin converting enzyme for blood pressure control. - APUD cells or neuroendocrine cells are present in the bronchiolar tree. they produce various vasoactive substances like VIP and substance P which may have a role in maintaining tone of bronchioles Defence function - Trapping of foreign particles by the mucus secreted by the goblet cells - Mucus contains IgA antibodies that provides local immunity. Alveolar macrophages - Preventing reflexes helps to clear air passage from the inhales foreign particles.

23. EXCHANGE OF GASES 1) External respiration Take place in the lung. Then oxygen is absorbed from air into the blood and CO2 is excreted from the blood into the air. 2) Internal respiration Also called tissue respiration. 02 is transferred from blood into the tissues; which gives up CO2.

24. RESPIRATORY MOVEMENTS Inspiration It is accompanied by expansion of lungs for uptake of air Expiration expulsion of air from the lung due to retraction of lungs.

25. MUSCLES OF RESPIRATION Primary or major Inspiratory muscles Accessory Expiratory muscles Diaphragm which is supplied by phrenic nerve(C3-C5) Sternocleidomastoid, Intercostal muscles: External Scaleni- 3 in neck- Anterior, posterior and middle Anterior serrati Elevators of scapular Pectoralis

26. Primary expiratory muscles Internal intercostal muscle Accessory respiratory muscles a) Abdominal muscles: Rectus abdominis, External oblique, Internal oblique and Transversus abdominis

27. MOVEMENT OF THORACIC CAGE ➤ Pump handle movement The contraction of external intercostal muscles causes elevation of 2nd to 6th pair of ribs and upward and forward movement of sternum. Increases anterior posterior diameter of the thoracic cage Bucket handle movement Contraction of external intercostals raises the lateral part of the ribs causing a bucket handling motion that increases the transverse diameter of thorax .

28. Movement of lungs During inspiration, due to the enlargement of thoracic cage , the negative pressure is increased in the thoracic cavity. It causes expansion of the lungs . During expiration, the thoracic cavity decreases in size to the pre-inspiratory position. The pressure in the thoracic cage also comes back to the pre- inspiratory level. It compresses the lung tissues so that, the air is expelled out of lungs.

29. Pressure of lungs Intra pleural pressure Throughout the respiratory cycle intra pleural pressure remains lower than intra alveolar pressure. This keeps lungs inflated. It is always negative Intra alveolar pressure Also called intra pulmonary pressure Normally it is equal to intra atmospheric pressure. 760mmhg It is negative during inspiration and positive during expiration It is measured by plethysmograph Transpulmonary pressure Difference between the intra-alveolar and intra-pleural pressure

30. LUNG VOLUMES AND LUNG CAPACITIES The lung volumes are of four types: 1. Tidal volume 2. Inspiratory reserve volume 3. Expiratory reserve volume 4. Residual volume.

31. TIDAL VOLUME(TV) Tidal volume is the volume of air breathed in and out of lungs in a single normal quiet respiration. Tidal volume signifies the normal depth of breathing. Normal Value: 500 mL (0.5 litre ). INSPIRATORY RESERVE VOLUME (IRV) Inspiratory reserve volume is an additional volume of air that can be inspired forcefully after the end of normal inspiration. Normal Value: 3300 mL(3.3 litres ). EXPIRATORY RESERVE VOLUME (ERV) Expiratory reserve volume is the additional volume of air that can be expired out forcefully, after normal expiration. Normal Value:1000 mL(1 litre ).

32. RESIDUAL VOLUME (RV) the volume of air remaining in the lungs even after forced expiration. Normally, lungs cannot be emptied completely even by forceful expiration. Residual volume is significant because of two reasons: i . It Helps to aerate the lungs in between breathing and during expiration II. It maintains the contour of the lungs. Normal Value:1200 mL(1.2 litre )

33. LUNG CAPACITIES lung capacities are the combination of two or more lung volumes. Lung capacities are of four types: 1. Inspiratory capacity 2. Vital capacity 3. Functional residual capacity 4. Total lung capacity.

34. 1. INSPIRATORY CAPACITY(IC) Inspiratory capacity is the maximum volume of air that is inspired after normal expiration (end expiratory position). It includes tidal volume and inspiratory reserve volume. IC=TV+IRV =500+3300=3800 mL

35. 2. VITAL CAPACITY(VC) It is the maximum volume of air that can be expelled out forcefully after a deep (maximal) inspiration. Vital capacity includes inspiratory reserve volume, tidal volume and expiratory reserve volume. VC=IRV+TV+ERV = 3300+500+1000=4800 mL

36. 3. FUNCTIONAL RESIDUAL CAPACITY(FRC) is the volume of air remaining in the lungs after normal expiration (after normal tidal expiration). Functional residual capacity includes expiratory reserve volume and residual volume. FRC=ERV+RV= 1000+1200=2200 mL

37. 4. TOTAL LUNG CAPACITY(TLC) Total lung capacity is the volume of air present in the lungs after a deep (maximal) inspiration. It includes all the volumes. TLC= IRV+TV+ERV+RV =3300+500+1000+1200=6000 ml

38. Ventilation Pulmonary ventilation A cyclic process by which fresh air enters the lungs and an equal volume of air leaves the lungs.it is the volume of air moving in and out of lung per minute in quite breathing Also called respiratory minute volume Normal value is 6L/min Alveolar ventilation It is the amount of air utilized for gaseous exchange every minute. Normal value is 4.2L/min

39. Ventilation-Perfusion Ratio It is the ratio of the alveolar ventilation to the pulmonary blood flow. Normal alveolar ventilation at rest is 4.24 L/minute, and pulmonary blood flow is 5 L/minute. Therefore, the ventilation-perfusion ratio is 4.2 L/5L or 0.84. The ventilation-perfusion ratio is high in the apex of the lungs and less in the base of the lungs (due to gravity). VPR= Alveolar ventilation/Pulmonary Blood flow

40. Introduction to Respiration Definition of Respiration Importance of Respiration for Survival Overview of Topics Covered

41. Anatomy of the Respiratory System Diagram of the Respiratory System Parts of the Respiratory System (Nose, Pharynx, Larynx, Trachea, Bronchi, Lungs) Function of Each Part

42. External Respiration Definition of External Respiration Process of External Respiration (Gas Exchange in the Alveoli) Role of Oxygen and Carbon Dioxide Diagram of Alveolar Gas Exchange

43. Internal Respiration Definition of Internal Respiration Process of Internal Respiration (Gas Exchange in Tissues) Role of Oxygen and Carbon Dioxide Diagram of Tissue Gas Exchange

44. Mechanics of Breathing

45. Inspiration vs. Expiration Role of Diaphragm and Intercostal Muscles Intrapleural Pressure and Lung Volume Changes Diagram of Thoracic Cavity During Breathing

46. Regulation of Respiration Control of Breathing by the Respiratory Center in the Brainstem Factors Affecting Breathing Rate and Depth (Chemoreceptors, Stretch Receptors, Emotional State) Regulation of Blood pH by Respiration