Respiratory system

1. RespiratorySystem

2. Introduction • The major function of the respiratory system is to supply the body with oxygen and removal of carbon dioxide • To achieve this function four distinct processes, collectively called respiration occur • • Pulmonary ventilation • External respiration • Transport of respiratory gases • Internal respiration (cellular respiration)

3. Parts of the Respiratory system  Nose  Pharynx  Larynx  Trachea  Bronchi  Lungs – alveoli

4. Gas exchange: Oxygen enters blood and carbon  dioxide leaves Regulation of blood pH: Altered by changing  blood carbon dioxide levels Voice production: Movement of air past vocal  folds makes sound and speech Olfaction: Smell occurs when airborne  molecules drawn into nasal cavity Protection: Against microorganisms by  preventing entry and removing them

5. Upper tract  Nose, pharynx  and associated structures Lower tract  Larynx, trachea,  bronchi, lungs

6. The organs of the respiratory system • Nose • Nasal cavity, • Paranasal sinuses • Pharynx • Larynx, • Trachea, • Bronchi, • Lungs which contain the terminal air sacs or alveoli

7. Pharynx Nose Common opening for External nose digestive and Nasal cavity respiratory systems Functions Three regions Passageway for air Nasopharynx Cleans the air Oropharynx Humidifies, warms air Laryngopharynx Smell Along with paranasal sinuses are resonating chambers for speech

8. Functions  Maintain an open passageway for air movement  Epiglottis and vestibular folds prevent swallowed material  from moving into larynx Vocal folds are primary source of sound production 

9. Windpipe  Divides to form  Primary bronchi  Carina: Cough reflex 

11. Lungs  Occupy most of the thoracic cavity  Apex is near the clavicle (superior portion)  Base rests on the diaphragm (inferior portion)  Each lung is divided into lobes by fissures  Left lung – two lobes  Right lung – three lobes Slide 13.12a

12. Coverings of the Lungs  Pulmonary (visceral) pleura covers the lung surface  Parietal pleura lines the walls of the thoracic cavity  Pleural fluid fills the area between layers of pleura to allow gliding Slide 13.13

13. Respiratory Tree Divisions  Primary bronchi  Secondary bronchi  Tertiary bronchi  Bronchioli  Terminal bronchioli Slide 13.14

14. Alveoli  Structure of alveoli  Alveolar duct  Alveolar sac  Alveolus Gas exchange occurs here. Slide 13.17

15. Respiratory Membrane (Air-Blood Barrier) Slide 13.18b

16. Events of Respiration Pulmonary ventilation: O2 into lungs from inspired air; CO2 out of lungs from expired air. External respiration: Gas exchange between alveoli and the capillaries. Respiratory gas transport: Gasses are transported in blood (via vessels) to tissues. Internal respiration: Gas exchange between blood and tissue cells in systemic capillaries Cellular respiration. Slide 13.20a

17. Mechanics of Breathing (Pulmonary Ventilation)  Two phases  Inspiration – flow of air into lung  Expiration – air leaving lung Slide 13.21b

18. Functionally, the respiratory structures are divided into respiratory and conducting zones • Visible structures represent the conducting zone • Respiratory zone structures are small and lie deep within the lungs

19. Organs of the conducting zone clean, warm and humidify the incoming air Thus, the air reaching the lungs contain must less dust than what entered the nose and is warm

20. Function • Mainfunctionofthe Respiratorysystem is toallowgas exchange.

21. AnatomicalFeatures • TheAnatomical featuresofthe respiratorysystemare airways,lungs,and therespiratory muscles.

22. RespiratoryBreakdown

23. Sinuses • TheSinusesarehollowspacesinthebonesof thehead.Smallopeningsconnectthemtothe nasalcavity.Thefunctionstheyservearenot clearlyunderstood,butincludehelpingto regulatethetemperatureandhumidityofair breathedin,aswellastolightenthebone structureoftheheadandtogiveresonanceto thevoice.

24. NasalCavity • TheNasalCavity(nose)isthepreferred entranceforoutsideairintotheRespiratory System.Thehairsthatlinetheinsidewallare partoftheair-cleansingsystem.

25. OralCavity • AiralsoentersthroughtheOralCavity(mouth), especiallyinpeoplewhohaveamouth-breathing habitorwhosenasalpassagesmaybe temporarilyobstructed,asbyacold.

26. Adenoids • TheAdenoidsareovergrownlymphtissueatthe topofthethroat.Whentheyinterferewith breathing,theyaregenerallyremoved.The lymphsystem,consistingofnodes(knotsof cells)andconnectingvessels,carriesfluid throughoutthebody.Thissystemhelpsresist bodyinfectionbyfilteringoutforeignmatter, includinggerms,andproducingcells (lymphocytes)tofightthem.

27. Tonsils • TheTonsilsarelymphnodesinthewallofthe pharynxthatoftenbecomeinfected.Theyare anunimportantpartofthegerm-fightingsystem ofthebody.Wheninfected,theyaregenerally removed.

28. Pharynx • ThePharynx(throat)collectsincomingairfrom thenoseandpassesitdownwardtothetrachea (windpipe).

29. Epiglottis • TheEpiglottisisaflapoftissuethatguardsthe entrancetothetrachea,closingwhenanything isswallowedthatshouldgointotheesophagus andstomach.

30. Larynx • TheLarynx(voicebox)containsthevocalcords. Itistheplacewheremovingairbeingbreathed inandoutcreatesvoicesounds.

31. Esophagus • TheEsophagusisthepassageleadingfromthe mouthandthroattothestomach.

32. Trachea • TheTrachea(windpipe)isthepassageleading fromthepharynxtothelungs.

33. Ribs • TheRibsarebonessupportingandprotecting thechestcavity.Theymovetoalimiteddegree, helpingthelungstoexpandandcontract.

34. Bronchi • ThetracheadividesintothetwomainBronchi (tubes),oneforeachlung.These,inturn, subdividefurtherintobronchioles.

35. RightLung • TheRightLungisdividedintothreeLobes,or sections. • TheleftlungisdividedintotwoLobes.

36. Pleura • ThePleura arethetwomembranes,that surround each lobeofthelungsand separatethelungsfromthechestwall

37. Cilia& Mucus • ThebronchialtubesarelinedwithCilia(likevery smallhairs)thathaveawave-likemotion.This motioncarriesMucus(stickyphlegmorliquid) upwardandoutintothethroat,whereitis eithercougheduporswallowed.Themucus catchesandholdsmuchofthedust,germs,and otherunwantedmatterthathasinvadedthe lungsandthusgetsridofit.

38. Diaphragm • TheDiaphragmthestrongwallofmusclethat separatesthechestcavityfromtheabdominal cavity.Bymovingdownward,itcreatessuction todrawinairandexpandthelungs.

39. Bronchioles • Thesmallestsubdivisionsofthebronchiare calledBronchioles,attheendofwhicharethe alveoli(pluralofalveolus).

40. Alveoli • TheAlveoliaretheverysmallairsacsthatare thedestinationofairbreathedin.TheCapillaries arebloodvesselsthatareimbeddedinthewalls ofthealveoli.Bloodpassesthroughthe capillaries,broughttothembythePulmonary arteryandtakenawaybythePulmonaryvein. Whileinthecapillariestheblooddischarges carbondioxideintothealveoliandtakesup oxygenfromtheairinthealveoli.