Respiratory SystemThose structures involved in exchange of gases between blood and external environmentLungsPassageways leading to lungsChest structures responsible for movement of air into and out of the lungsTerminologyPressure (P)Force per unit of are (cm H20)Volume (V)Size of cavity, or amount of air in cavity (cc, ml, L)Volume Flow RateRate at which 1 cc of air moves past a point in 1 secOr, volume of air passing a point in 1 sec (cc/s, LPS)Resistance (R)In aerodynamics, opposition offered to flow of air through a systemRatio of pressure drop across length of system to volume rate of air flow through itR = P/V = cm H20/LPSGas LawsAir is a compressible gasTherefore, can exert pressureTo measure pressure, must exert force against resistanceForce exerted by air against 1 sq. in. of earth at sea level = 14.7 lb/sq. inBody area = 3000 sq. in.Therefore, >43,000lb/sq.in. exerted on bodyBoyles lawPressure of a gas is inversely proportional to its volume with temperature constantNewtons LawAn unbalanced force acting on any body (solid, liquid, gas) will cause an acceleration ….Air will flow from region of high to low pressureLung—Thorax UnitOuter surface of lungs covered by visceral pleuraInner surface of thorax and superior surface of diaphragm covered by parietal pleuraSeparated by intrapleural spaceFluid filled negative pressure interface that links two togetherIntact system called “lung—thorax unit”Rest position of intact lung—thorax unit represents mechanical equilibriumLungs expanded relative to disconnected stateThorax compressed relative to disconnected stateEquilibrium position referred to as Resting Expiratory level (REL)volume of air in lungs at REL approximately 37% of vital capacityExhalation (major muscles)Rectus AbdominusExternal ObliquesInternal ObliquesTransverse AbdominusAbdominal AponeurosisExtends from…Lower fibers of pectoralis majorXiphoid process of sternumCostal cartilagesInferiorly to…Pubic symphysis and anterior iliac spine(white is aponeurosis; tendon sheet)running down the midlin is linea alba (dark white line)Rectus AbdominusLong ribbon-like muscle on ventral aspect of abdominal cavityAlmost entirely enclosed by aponeurosisOrigin—anterior edge of pubic boneCourse—superior, parallel to midlineInsertion—cartilages of ribs 5-7, xiphoid process(tendonous tissue ties down the abs)External Obliquelargest, strongest, and most superficial abdominal musclebroad, flat muscle on lateral and anterior portions of lower thorax and abdomenorigin—iliac crest and aponeurosisCourse—superior and lateral/posteriorInsertion—ribs 5-12(finger looking things are serratus muscles pulling scapula forward)Internal Obliquemiddle layer of abdominal musculaturelies just deep to external obliqueslarge, flat muscle on later and ventral aspect of abdomenOrigin—anterior ½ of iliac crest and inguinal ligamentCourse—fans out superiorly and anteriorly/mediallyInsertion—abdominal aponeurosis and cartilagesTransverse AbdominusDeepest abdominal muscleLies just deep to internal obliquesOrigin—ribs 6-12, ¾ of iliac crest, and lateral 1/3 of inguinal ligamentCourse—horizontalInsertion—deepest layer of abdominus aponeurosisAbdominal muscle action1. Flexor of vertebral column2. Enclose and support abdominal contentsHernea- weakness in the aponeurosis, opens up and allows abdominal contents to squeeze through3. Respiration1. Displace abdominal contents and increase abdominal pressure2. Draw ribs inferiorlyObliques more efficient rib depressorsTransverse abdominus more efficient compressorComing around the abdominal domeExhalation (accessory muscles)SubcostalsInternal IntercostalsTransverse thoracisSerratus PoSubcostalsOn posterior aspect of inner wall of lower thoracic cageHighly variable (some of us have some don’t have them)Some more, others lessOrigin—inner surface of ribs, close to vertebral columnCourse—superior and lateralInsertion—inner surface of rib 1 or 2 aboveAction—presumes to depress ribsInternal IntercostalsNot as prominent and strong as external intercostalsLie just deep to external intercostalsOrigin—superior surface of lower rib of pairCourse—superior and towards sternumInsertion—lower border of rib aboveAction—depress ribsTransverse ThoracisOn inner surface of anterior thoracic wallOrigin—inner surface of sternum and costal cartilages 5-7Course—fan out superiorly and laterallyInsertion—inner surface of ribs 2-6Action—presumed to depress ribsSerratus PosteriorOn lower posterior portion of thoraxOrigin—via aponeurosis from T11-12 and L1-3Course—superior and lateralInsertion –lower border or ribs 8-12 just beyond angleAction—presumed to pull down on lower ribsQuadratus LumborumPosterior muscle of abdomenFlat sheet of muscle on lateral dorsal aspect of abdominal wallOrigin—iliac crest and iliolumbar ligamentCourse—superiorInsertion—transverse process of L1-4 and rib 12Action—depress rib 12Csd 3112 1st Edition Lecture 10 Outline of Last Lecture I. Respiratory System Anatomy cont.II. Exhalationa. Major musclesi. Abdominal Aponeurosisii. Rectus Abdominusiii. Obliqueiv. Transverse Abdominusv. Abdominus muscle actionb. Accessory Musclesi. Subcostalsii. Internal intercostalsiii. Transverse thoracisiv. Serratus posteriorv. Quadratus lumborumOutline of Current Lecture III. Respiratory System Physiologya. TerminologyIV. Gas lawsV. Lung Thorax UnitCurrent LectureRespiratory System Physiology p1These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. Respiratory System- Those structures involved in exchange of gases between blood and external environment- Lungs- Passageways leading to lungs- Chest structures responsible for movement of air into and out of the lungs Terminology- Pressure (P)o Force per unit of are (cm H20)- Volume (V)o Size of cavity, or amount of air in cavity (cc, ml, L)- Volume Flow Rateo Rate at which 1 cc of air moves past a point in 1 seco Or, volume of air passing a point in 1 sec (cc/s, LPS)- Resistance (R)o In aerodynamics, opposition offered to flow of air through a systemo Ratio of pressure drop across length of system to volume rate of air flow through ito R = P/V = cm H20/LPS Gas Laws- Air is a compressible gaso Therefore, can exert pressure- To measure pressure, must exert force against resistance- Force exerted by air against 1 sq. in. of earth at sea level = 14.7 lb/sq.