RESPIRATORY SYSTEM and the functions .pptx

Respiratory system and their functions

1. RESPIRATORY SYSTEM

2. RESPIRATION – it is the act of breathing Inhaling – the act of breathing in oxygen Exhaling – the act of breathing out carbon dioxide

3. The parts of respiratory system are Nose Mouth Throat (pharynx) Larynx(voice box) Trachea(wind pipe) Bronchi(large airways) Bronchioles (small air passages) Lungs

4. Structurally respiratory system consists of two parts Upper respiratory system and lower respiratory system Upper respiratory tract includes nose, nasal cavity, pharynx and associated structures Lower respiratory tract includes larynx, trachea, bronchi and lungs

5. Functionally it is classified as respiratory zone and conducting zone Conducting zone –consists of a series of interconnecting cavities and tubes both outside and within the lungs. These includes nose, nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles. Their function is to filter, warm and moisten air and conduct it in to the lungs Respiratory zone – consists of tubes and tissues within the lungs where gas exchange occurs. These include the respiratory bronchioles, alveolar ducts, alveolar sac and alveoli(gas exchange occur in these zone)

6. Respiratory muscles – Diaphragm and other muscles promotes respiration Respiratory mucosa – It is a layer of pseudostratified ciliated columnar epithelial cells that secrete mucus. Found in nose, sinuses, pharynx, larynx and trachea Mucus can trap contaminants Cilia move mucus up towards the mouth

7. Exchange of gases Two phases External respiration - It takes place in the lungs. O2 is absorbed from air into the blood and CO2 is excreted from the blood into the air Internal respiration – It takes place at the tissue level (tissue respiration). O2 is transferred from blood to the tissues, which give up CO2

8. Nose and nasal cavity Nose has mainly two functions to perform they are It is a part of the respiratory passage It has the olfactory function or the sense of smell Nose provides entrance for air in which air is filtered by hairs inside the nostrils Nose is divided into two portions External nose Internal nasal cavity

9. External portion is covered by a framework of bone and cartilage covered with skin and lined with mucus membrane The internal portion is a large cavity in the skull, merging with the external nose anteriorly and communicating with the throat posteriorly

10. Nose has a prominent ridge, separating the right and left halves, called the dorsum Upper narrow end of the nose is called the root of the nose The lower end of the dorsum is called the tip of the nose At the lower end of the nose there are two openings – the right and left nostrils – which are separated by a soft median portion called columella Each nostril is bounded anteriorly by ala The nasal skeletal framework is partially bony and partially cartilaginous

11. Nasal cavity It is pyramidal in shape Lies in and posterior to the external nose It is divided by midline nasal septum Ethmoid and sphenoid bone forms the roof Floor is formed by the hard and soft palate It extends from the nostrils to the posterior nasal apertures (choanae) The nasal cavity is divided into right and left halves by a median septum

12. Subdivisions of nasal cavity Vestibule - It is the dilated part. It contains numerous coarse hairs called vibrissae, which helps to filter the air Olfactory mucosa The upper 1/3 rd of the nasal cavity has the olfactory receptor cells The mucosa is yellowish in color Respiratory region The lower 2/3 rd of the nasal cavity is lined by thick mucous membrane, which is highly vascular and lined by pseudostratified ciliated epithelium

13. It is the dilated part. It contains numerous coarse hairs called vibrissae, which helps to filter the air The upper 1/3 rd of the nasal cavity has the olfactory receptor cells The mucosa is yellowish in color The lower 2/3 rd of the nasal cavity is lined by thick mucous membrane, which is highly vascular and lined by pseudostratified ciliated epithelium

14. Boundaries of the nasal cavity Each half of the nasal cavity has a roof, a floor, a medial wall and a lateral wall Each half is 5-7cm in length, 1.5cm in width(floor) and 1-2mm at the roof Roof is mainly formed by the cribriform plate of the ethmoid bone Anteriorly roof is formed by the nasal bone and nasal part of the frontal bone Posteriorly it is by the body of the sphenoid bone Floor is formed by the palate

15. The medial wall or the nasal septum It is a median osteocartilaginous partition between two halves of the nasal cavity It is covered on either side by mucus membrane

16. Components The bony part Bony part of the nasal septum is formed by the vomer and Perpendicular part of the ethmoid bone Frontal, maxilla, nasal and sphenoid also contribute Cartilaginous part Septal cartilage Inferior nasal cartilage Cuticular part Formed by fibro fatty connective tissue covered by skin The lower margin of the septum is called columella

17. Blood supply to the septum It is supplied by branches of anterior ethmoidal artery Superior labial branch of fascial artery The sphenopalatine branch of palatine artery Little’s area It is an area at the anteroinferior quadrant because of the rich anastomosis between all the arteries supplying the nasal septum

18. Venous drainage - the corresponding veins drain into the fascial vein and pterygoid venous plexus Nerve supply General sensory – branches of the trigeminal nerve Special sensory – olfactory receptor cells Applied anatomy DNS Epistaxis

19. The lateral wall of the Nose It is irregular Having three shelf like bony projections called turbinates or conchae According to their position they are called as superior , middle and inferior nasal conchae Superior and middle conchae are the parts of the ethmoid bone Inferior conchae is an independent bone

20. Superior meatus It is a narrow passage between the superior and middle conchae Middle meatus It is the longer and wider passage between the middle nasal conchae and lateral nasal wall It has a funnel shaped opening in its anterosuperior part called the infundibulum The frontal sinus opens into the infundibulum Inferior meatus It lies underneath the inferior concha It is the largest of the three meatus The nasolacrimal duct opens into it

21. Arterial supply – Ethmoidal artery and branches of maxillary artery Nerve supply – Branches of trigeminal nerve