respiration. ontogenesis of respiration. respiration. ontogenesis of respiration

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  • Respiration. Ontogenesis of respiration.

  • *The Respiratory SystemCells continually use O2 & release CO2Respiratory system designed for gas exchangeCardiovascular system transports gases in bloodFailure of either system rapid cell death from O2 starvation

  • *Shina Alagia*Respiratory System AnatomyNosePharynx = throatLarynx = voiceboxTrachea = windpipeBronchi = airwaysLungs- upper respiratory tract is above vocal cordslower respiratory tract is below vocal cords

    Shina Alagia

  • *Shina Alagia*External Nasal StructuresSkin, nasal bones, & cartilage lined with mucous membraneOpenings called external nares or nostrils

    Shina Alagia

  • *Shina Alagia*Nose -- Internal StructuresLarge chamber within the skullRoof is made up of ethmoid and floor is hard palateInternal nares are openings to pharynxNasal septum is composed of bone & cartilageBony swelling or conchae on lateral walls

    Shina Alagia

  • *Shina Alagia*Functions of the Nasal StructuresOlfactory epithelium for sense of smellPseudostratified ciliated columnar with goblet cells lines nasal cavitywarms air due to high vascularitymucous moistens air & traps dustcilia move mucous towards pharynxParanasal sinuses open into nasal cavityfound in ethmoid, sphenoid, frontal & maxillarylighten skull & resonate voice

    Shina Alagia

  • *Shina Alagia*Pharynx Muscular tube (5 inch long) hanging from skullskeletal muscle & mucous membraneExtends from internal nares to cricoid cartilageFunctionspassageway for food and airresonating chamber for speech productiontonsil (lymphatic tissue) in the walls protects entryway into bodyDistinct regions -- nasopharynx, oropharynx and laryngopharynx

    Shina Alagia

  • *Shina Alagia*NasopharynxFrom internal nares to soft palateopenings of auditory (Eustachian) tubes from middle ear cavityadenoids or pharyngeal tonsil in roof

    Shina Alagia

  • *Shina Alagia*OropharynxFrom soft palate to hyoid bonefauces is opening from mouth into oropharynxpalatine tonsils found in side walls, lingual tonsil in tongueCommon passageway for food & air

    Shina Alagia

  • *Shina Alagia*LaryngopharynxExtends from hyoid bone to cricoid cartilageCommon passageway for food & air & ends as esophagus inferiorly

    Shina Alagia

  • *Shina Alagia*LarynxCartilage & connective tissue tubeAnterior to C4 to C6Constructed of 3 single & 3 paired cartilages

    Shina Alagia

  • *Shina Alagia*Vocal CordsFalse vocal cords (ventricular folds) found above vocal folds (true vocal cords)True vocal cords attach to arytenoid cartilages

    Shina Alagia

  • *Shina Alagia*Trachea and Bronchial TreeFull extent of airways is visible starting at the larynx and trachea

    Shina Alagia

  • *Shina Alagia*TracheaCiliated pseudostratified columnar epithelium Hyaline cartilage as C-shaped structure closed by trachealis muscle

    Shina Alagia

  • *Shina Alagia*Bronchi and BronchiolesPrimary bronchi supply each lungSecondary bronchi supply each lobe of the lungs (3 right + 2 left)Tertiary bronchi supply each bronchopulmonary segmentRepeated branchings called bronchioles form a bronchial tree

    Shina Alagia

  • *Shina Alagia*Pleural Membranes & Pleural CavityVisceral pleura covers lungs --- parietal pleura lines ribcage & covers upper surface of diaphragmPleural cavity is potential space between ribs & lungs

    Shina Alagia

  • *Shina Alagia*Gross Anatomy of LungsBase, apex (cupula), costal surface, cardiac notchOblique & horizontal fissure in right lung results in 3 lobesOblique fissure only in left lung produces 2 lobes

    Shina Alagia

  • *Shina Alagia*Mediastinal Surface of LungsBlood vessels & airways enter lungs at hilusForms root of lungsCovered with pleura

    Shina Alagia

  • *Shina Alagia*Structures within a segment of LungBranchings of single arteriole, venule & bronchiole are wrapped by elastic CTRespiratory bronchiolesimple squamousAlveolar ducts surrounded by alveolar sacs & alveolisac is 2 or more alveoli sharing a common opening

    Shina Alagia

  • *Shina Alagia*Cells Types of the AlveoliType I alveolar cellssimple squamous cells where gas exchange occursType II alveolar cells (septal cells)free surface has microvillisecrete alveolar fluid containing surfactantAlveolar dust cellswandering macrophages remove debris

    Shina Alagia

  • *Shina Alagia*Alveolar-Capillary MembraneRespiratory membrane = 1/2 micron thickExchange of gas from alveoli to blood4 Layers of membrane to crossalveolar epithelial wall of type I cellsalveolar epithelial basement membranecapillary basement membraneendothelial cells of capillary

    Shina Alagia

  • *Shina Alagia*Details of Respiratory MembraneFind the 4 layers that comprise the respiratory membrane

    Shina Alagia

  • *Shina Alagia*Double Blood Supply to the LungsDeoxygenated blood arrives through pulmonary trunk from the right ventricleBronchial arteries branch off of the aorta to supply oxygenated blood to lung tissueVenous drainage returns all blood to heartPulmonary blood vessels constrict in response to low O2 levels so as not to pick up CO2 on there way through the lungs

    Shina Alagia

  • *Shina Alagia*RespirationRespiration is exchange of primarily oxygen and carbon dioxide between atmosphere and human body

    Shina Alagia

  • *Shina Alagia*Respiration: StepsRespiration is achieved in four stepsPulmonary ventilation: Inspiration + ExpirationExternal respiration: Diffusion across alveolar-capillary membraneGas transport: Transport of O2 and CO2Internal respiration: Exchange between ICF and tissue capillary

    Shina Alagia

  • *Shina Alagia*Breathing or Pulmonary VentilationAir moves into lungs when pressure inside lungs is less than atmospheric pressureHow is this accomplished?Air moves out of the lungs when pressure inside lungs is greater than atmospheric pressureHow is this accomplished?Atmospheric pressure = 1 atm or 760mm Hg

    Shina Alagia

  • *Shina Alagia*Boyles LawAs the size of closed container decreases, pressure inside is increasedThe molecules have less wall area to strike so the pressure on each inch of area increases.

    Shina Alagia

  • *Shina Alagia*Dimensions of the Chest CavityBreathing in requires muscular activity & chest size changesContraction of the diaphragm flattens the dome and increases the vertical dimension of the chest

    Shina Alagia

  • *Shina Alagia*Diaphragm moves 1 cm & ribs lifted by external intercostal musclesIntrathoracic pressure falls and 2-3 liters inhaledQuiet Inspiration

    Shina Alagia

  • *Shina Alagia*Passive process with no muscle actionElastic recoil & surface tension in alveoli pulls inwardAlveolar pressure increases & air is pushed outQuiet Expiration

    Shina Alagia

  • *Shina Alagia*Intra-pleuralPressures

    Helps keep parietal & visceral pleura stick together and alveoli inflatedAlways subatmospheric (756 mm Hg)As diaphragm contracts intrapleural pressure decreases even more (754 mm Hg)

    Shina Alagia

  • *Shina Alagia*Summary of BreathingAlveolar pressure decreases & air rushes inAlveolar pressure increases & air rushes out

    Shina Alagia

  • *Shina Alagia*External RespirationExchange of gas between air & bloodGases diffuse from areas of high partial pressure to areas of low partial pressureDeoxygenated blood becomes oxygenetedCompare gas movements in pulmonary capillaries to tissue capillaries

    Shina Alagia

  • *Shina Alagia*Internal RespirationExchange of gases between blood & tissuesConversion of oxygenated blood into deoxygenatedObserve diffusion of O2 inwardat rest 25% of available O2 enters cellsduring exercise more O2 is absorbedObserve diffusion of CO2 outward

    Shina Alagia

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