Respiratory system

ANATOMY OF RESPIRATORY SYSTEM

1. THE RESPIRATORY SYSTEM BY: Mrs.Keerthi Samuel, Asst.Professor , VMCON

2. INTRODUCTION

3. CLASSIFICATION- STRUCTURAL UPPER RESPIRATORY TRACT LOWER RESPIRATORY TRACT

4. CLASSIFICATION-FUNCTIONAL CONDUCTING ZONE RESPIRATORY ZONE

5. OTO-RHINO-LARYNGOLOGY

6. ANATOMY OF THE NOSE

7. NOSE IS DIVIDED INTO EXTERNAL NOSE INTERNAL NOSE

8. EXTERNAL NOSE BONY FRAMEWORK CARTILAGENOUS FRAME WORK FRONTAL L OR ALAR.C EXTERNAL NARES NASAL CARTILAGE OR ALAR CARTILAGE

9. FUNCTIONS

10. INTERNAL NOSE Large cavity in the anterior aspect of the skull. Inferior to the nasal bone Superior to the mouth Covered by muscle and mucous memebrane Anteriorly merges with ext.Nose Posteriorly opens into pharynx through 2 openings called CHONAE/INTERNAL NARES

11. INTERNAL NOSE Lateral wall- Ethmoid,Maxilla Roof - Ethmoid bone Floor – Palatine bones of Maxilla Space in the int. nose is called Nasal cavity. The anterior part of internal nostrils- VESTIBULE.

12. INTERNAL NOSE Nasal septum , a vertical partition divides nasal cavity into right and left halves. When air enters into the nostrils it first enters into the vestibule, that is lined by skin containing coarse hairs that filters out large dust particles.

13. INTERNAL NOSE- MEATUS The projections of superior, inferior and middle CONCHAE forms three shelves which subdivides the nasal cavity into: SUPERIOR MEATUS : olfactory receptors MIDDLE MEATUS INFERIOR MEATUS Lined by mucous membranes which traps the water during inhalation to prevent drying.

14. OLFACTORY EPITHELIUM Inferior to the olf.epithelium there are capillaries and pseudostratified ciliated columnar epithelium+ GOBLET CELLS which traps dust and moistens air. CILIA- Moves trapped dust particles towards pharynx thus allowing us to swallow and hence dust is removed from respiratory tract.

15. ANATOMY OF PHARYNX

16. PHARYNX/THROAT Funnel shaped tube. Length-13cms. Starts at interal nares and extends to the lecel f cricoid cartilage , the most inferior cartilage of larynx. POSITION: posterior to nasal and oral cavities, superior to larynx, just anterior to cervical vertebrae. Wall is composed of skeletal muscles and is lined by mucous membrane.

17. FUNCTIONS OF PHARYNX

18. DIVISION AND MUSCLES OF PARYNX The muscles of pharynx are arranged into: Outer circular layer Inner longitudinal layer The superior portion of pharny is called NASOPHARYNX- which lies posterior to the nasal cavity and soft palate.

19. OPENINGS OF PHARYNX There are 5 openings in the wall of pharynx: 2 internal nares 2 auditory/Eustachian tubes. 1 opening into oropharynx. The posterior wall has –PHARYNGEAL TONSIL

20. NASOPHARYNX Receives air from nasal cavity along with packages of dust laden mucus. Lined by pseudostratified ciliated columnar epithelium- cilia moves mucus downwards to the inferior part of pharynx

21. OROPHARYNX Intermediate portion. Lies posterior to oral cavity and extends from soft palate inferior to the level of hyoid bone. It has only one opening called FAUCES the opening from mouth. It has both digestive and respiratory functions which is a common passage for air ,food and drink.

22. OROPHARYNX Because oropharynx is subjected to abrasion by food particles- it is lined by non keratinized stratified squamous epithelium. Two pairs of tonsil are housed : PALATINE AND LINGUAL TONSILS.

23. LARYNGOPHARYNX/ HYPOPHARYNX Begins at the level of hyoid bone. Opens posteriorly into esophagus and larynx anteriorly Both respiratory and digestive fuctions hence lined by non keratinized stratified squamous epithelium.

24. ANATOMY OF LARYNX

25. LARYNX-LOCATION Short passageway that connects laryngopharynx with the trachea. Lies in the midline of neck anterior to esophagus and through (C3-C6) cervical vertebrae.

26. Aretynoid influences change in the position and tension of vocal cords.

27. 1.THYROID CARTILAGE/ADAM’S APPLE 2 fused plates of hyaline cartilage that forms anterior wall of larynx and gives it a triangular shape. Present both in males and females , but larger in males due to male sex hormone on its growth during puberty. THYROHYOID MEMBRANE - connects thyroid cartilage with hyoid membrane.

28. 2.EPIGLOTTIS Large leaf shaped piece of elastic cartilage that is covered with epithelium. There are 2 parts STEM : Tappered inferior portion attached to the rim of thyroid cartilage LEAF -Broad superior portion- unattached and is free to move up and down like a trap door

29. 2.EPIGLOTTIS During swallowing the pharynx and larynx rise . Elevation of pharynx widens it to receive food and drink. Elevation of larynx causes epiglottis to move downward and form a lid over GLOTTIS, closing it off. The closing of larynx in this way during swallowing routes liquids and foods into esophagus and prevents into larynx. When a small particle of dust ,smoke or liquid passes into larynx , a cough reflex occurs , usually expelling the material. 2.EPIGLOTTIS GLOTTIS

30. LARNYX 3.CRICOID CARTILAGE It’s a ring of hyaline cartilage that forms the inferior wall of larynx. CRCICOTHYROID LIGAMAENT: attached to the first ring of trachea connecting the cricoid to thyroid cartilage. Site for emergency tracheostomy 4. ARYTENOID CARTILAGE Triangular pieces of mostly hyaline cartilage located to posterior, superior boarder of cricoid cartilage. Supported by arytenoid cartilage , the intrinsic muscles of pharyngeal muscle contract and move vocal cords to produce sound.

31. LARNYX 5.Cuneiform CARTILAGE Club shaped elastic cartilage anterior to corniculate cartilage Supports the vocal cords and lateral aspects of epiglottis. Horn shaped pieces of cartilages located at the apex of each arytenoid cartilage . They are the supporting structures of epiglottis. 4. CORNICULATE CARTILAGE

32. VOCAL CORDS The mucous membrane of larynx forms 2 pairs of folds: The superior pair- FALSE VOCAL CORDS/VENTRICULAR FOLDS The inferior pair - VOCAL FOLDS/TRUE VOCAL CORDS-principle structures of voice production. The space between ventricular folds is known as RIMA VESTIBULI. When ventricular folds are brought together they function in holding the breath against pressure in thoracic cavity (Ex: strain while lifting heavy object)

33. VOCAL CORDS When the intrinsic muscles of larynx contract there will be abduction of vocal cords. When the muscles relax – adduction of vocal cords – production of sound-PITCHED. Whispering do not cause closure of vocal cords or they donot vibrate.

34. TRACHEA/WIND PIPE Tubular passage way for air . Length is about 12cms and width is 2.5cms Located anterior to esophagus and extends from larynx to T5 and then divides into right and left bronchi. It provides protection against dust.

35. TRACHEA-layers

36. TRACHEA/WIND PIPE Rings are felt through skin inferior to larynx. Open part of C shaped cartilages faces esophagus- this arrangement accommodates slight expansion of esophagus into trachea during swallowing Transverse smooth muscle fibers –trachealis muscle and elastic tissue stabilize the open ends of cartilaginous rings. The solid C shaped rings provide semirigid support so that tracheal wall does not collapse inward and obstruct

37. BRONCHI At the superior boarder of 5 th thoracic vertebra, the trachea divides into: RIGHT PRIMARY BRONCHUS- More vertical ,shorter and wider than LEFT PRIMARY BRONCHUS. Hence the aspirated object is likely to enter and lodge into right primary bronchus than the left. Like trachea the primary bronchus contain incomplete rings of cartilage and are lined by pseudostratified ciliated columnar epithelium.

38. BRONCHI The point where trachea divides into right and left primary bronchi there is an internal ridge called ‘CARINA.’ The mucous membrane of carina is one of the most sensitive areas of entire larynx and trachea for triggering a cough reflex. Widening and distortion of carina is a serious sign because it usually indicates a carcinoma of lymphnodes around region where trachea divides.

39. BRONCHAL TREE IT LOOKS LIKE AN INVERTED TREE , ITS CALLED BRONCHIAL TREE

40. ANATOMY OF LUNGS

41. LUNGS Paired, cone shaped organs in the thoracic cavity. They are separated from each other by the heart and other structures in mediastinum, which divides the thoracic cavity into 2 anatomically distinct chambers. Two layers of serous membranes collectively called PLEURAL MEMBRANE enclose and protect each lung.

42. LUNGS- PLEURA PARIETAL PLEURA - Superficial layer, lines the wall of the thoracic cavity. VISCERAL PLEURA – deeper layer and covers the lungs themselves. Between the visceral and parietal pleura there is a small place called PLEURAL CAVITY - contains small amount of lubricating fluid called PLEURAL FLUID secreted by the membrane allowing them to slide easily over one another during breathing

43. LUNGS- PLEURA Pleural fluid also causes the two membranes to one another just as a film of water causing two layers to slide and stick together , a phenomenon called ‘SURFACE TENSION’ Separate pleural cavities surround the left and right lungs. Inflammation of pleural membranes is called PLEURITIS . Accumulation of fluid in pleural space is called PLEURAL EFFUSION.

44. LUNGS- PARTS The lungs extends from diaphragm to just slightly superior to the clavicles and lies against the ribs anteriorly and posteriorly. The broad inferior portion of the lung- BASE -concave and fits over the convex area of diaphragm. The narrow superior portion of the lung- APEX

45. LUNGS- SURFACES 1. COASTAL SURFACE –Matches the rounded curvature of ribs. 2. MEDIASTINAL SURFACE- Contains a region called hilum through which bronchi, pleural blood vessels, lymphatic vessels and nerves enter and exit. Medially left lung contains concavity the CARDIAC NOTCH in which the heart lies.

46. LUNGS Due to the space occupied by the heart ,the left lung is about 10% smaller than the right lung. Although the right lung is thicker and broader ,it is somewhat shorter than the left lung because the diaphragm is higher on right side, accommodating the liver that lies inferior to it. The lungs fills the thorax and is the only area that can be palpated

47. LUNGS The base of the lung extends from the 6 th intercostal cartilage anteriorly to spinous process of 10 th thoracic vertebra posteriorly. The pleura extends about 5cms below its base – 6 th costal cartilage anteriorly and 12 th rib posteriorly. Thus the lungs donot completely fill the pleural cavity in this area.

48. LUNGS- LOBES,FISSURES, LOBULES One or two fissure divide each lung into lobes. Both the lungs has OBLIQUE FISSURE , which extends inferiorly and anteriorly. Right lung has – HORIZONTAL FISSURE . OBLIQUE FISSURE - divides left lung INTO SUPERIOR AND INFERIOR LOBE. In the right lung the superior part of oblique fissure separates the superior lobe from the inferior lobe . The inferior part of the oblique fissure separates the inferior lobe from middle lobe.

49. LUNGS- BRONCHI Each lobe receives its own secondary bronchus : thus right bronchus gives the secondary bronchi ( Superior, middle and inferior lobar bronchi) Within the lung secondary bronchi gives rise to tertiary bronchi (approx. 10 tertiary bronchi are seen in each lung). The segment of lung tissue that each tertiary bronchus supplies is called ‘BRONCHO-PULMONARY SEGEMENT’

50. LUNGS- BRONCHI Each segment of lungs has many compartments called LOBULES . Each lobule is wrapped in elastic connective tissue and has lymphatic vessels, arterioles, venule and a branch from terminal bronchiole----------- divides into REPIRATORY BRONCHIOLES which subdivide into ALVEOLAR DUCTS.

51. ALVEOLI

52. ALVEOLI Around the circumference of the alveolar ducts are numerous alveoli and alveolar sacs. An ALVEOLUS is a cup shaped outpouching lined by simple squamous epithelium and supported by a thin elastic basement membrane. An alveolar sac consists of two or more alveoli that share a common opening.

53. ALVEOLI-CELLS The walls of alveoli consists of two types of alveolar epithelial cells: TYPE –I ALVEOLAR CELLS : simple squamous epithelial cells that form a nearly continuous lining of the alveolar wall. The thin type –I alveolar cells are the main sites for gaseous exchange. 2. TYPE-II or SEPTAL CELLS : fewer in number and are found between type-I cells. Rounded or cuboidal epithelial cells with free surfaces containing microvilli which secrete alveolar fluid.

54. ALVEOLI-CELLS The alveolar fluid keeps the surface between the cells and the air moist. Included in the alveolar fluid is SURFCTANT, a complex mixture of phospholipids and lipoproteins. Surfactant lowers the surface tension of the alveolar fluid , which reduces the surface tension of alveolar fluid and reduces the tendency of alveoli to collapse thus maintains the patency.

55. ALVEOLI-CELLS Associated with the alveolar wall are ALVEOLAR MACROPHAGES /DUST CELLS-phagocytes that remove fine dust particles and other debris from the alveolar spaces. Also there are fibroblasts that produce reticular and elastic fibers Underlying the layer of type-I cells is an elastic basement membrane On the outer surface of the alveoli the lobules arteriole and venules forms a network of capillaries .

56. RESPIRATORY MEMEBRANE The exchange of gases takes place across the alveolar and capillary walls, which together forms the RESPIRATORY MEMBRANE which is composed of four layers. A layer of type-I and Type-II alveolar cells ad associated alveolar macrophages that constitutes the alveolar walls. An EPITHELIAL BASEMENT MEMBRANE underlying the alveolar wall. A CAPILLARY BASEMENT MEMBRANE that is often fused to the epithelial basement membrane. The CAPILLARY ENDOTHELIUM

57. RESPIRATORY MEMEBRANE Despite having several layers the respiratory membrane is very thin only 0.5 micrometers thick, to allow rapid diffusion of gases. It has been estimated that the lungs contain 300million alveoli, providing an immense surface area of 70m2-about the size of racquet court for gs exchange