Anatomy and Physiology Exam 4 (FINAL)FigueroaRespiratory System- Mechanics of breathing (Pulmonary ventilation)o Inspiration- air flows into lungs Move fresh air IN to the body to the alveoluso Expiration- gas exits the lungs This EXIT (Ex) means out, move air with CO2 from alveolus OUT of the body- The Respiratory system starts in nose or mouth, goes to trachea, and bifurcates into primary bronchus, will divide to secondary bronchus, and intothe lungso Organs of respiration: Nose Nasal cavity Pharynx Larynx Trachea Bronchus Lungs- Major function:o Provide blood with oxygen (O2) and get rid of Carbon dioxide (CO2)- Branching of the bronchial tree:-Conducting Zone (the function is to conduct air to the respiratory zone)oConsidered “conducting zone” because NO alveoli (so no actual gas exchange occurs in the conducting zone)oMove airBronchiSubdivided into Secondary Bronchi, each supplying a lobe of the lungsThere are 23 orders of branching in the lungs that air must pass throughBig tubes contain cartilage, small tubes lack cartilageoCuboidal epithelium, smooth muscle, oCONSISTS of: Trachea Primary bronchi Secondary bronchi Tertiary bronchi Bronchioles- Respiratory Zone (HAVE alveoli, terminal bronchioles feed into respiratory bronchioles)o Terminal bronchioleso Respiratory bronchioleso Alveolar ductso Alveolar sacso Alveoli- There are ~ 300 million alveoli-This makes up most of the lungs’ volume-There are tiny sacs on alveoli (don’t confuse with alveolar sacs) which account for a greater surface area for gas exchangeo**Capillaries cover alveoli**o6 capillaries cover the alveoliAir blood barrier:o Composed of alveolar and capillary wallso Fused basal laminaso O2 diffuses into the cell and CO2 diffuses out of the cellso There is liquid in between the lungs and the blood capillariesAlveolar walls:oEpithelial cellsoPermit gas exchange by simple diffusionoSecrete ACE which converts to angiotensin 1 and 2Pressure relationships in the thoracic cavity:Air flow is the difference in pressure, so we change our thoracic pressureoalways described in atmospheric pressure (Patm)o(Patm) is exerted by air surrounding body so therefore:onegative respiratory pressure is less than (Patm)oleads to inhalation so air can go from high pressure outside of body to low pressure inside the bodyopositive respiratory pressure is greater than (Patm)oleads to exhalation so air can go from high pressure inside the body to low pressure outside the bodyo(Patm)= 760 mm at sea levelo** think that pressure always go from high to low**oInhalation and exhalation are same as inspiration/expirationoMain muscle is the diaphragm. oWhen diaphragm contracts: it comes down. Inspiratory. Move air in. high to lower pressure.o*think of taking a deep breath In, you are elongating your body and thoracic cavity.oWhen we relax the diaphragm: it will go up, thoracic cavity gets smaller. There is more pressure. oThe main muscle for exhalation is abdominals. Think of someone punching you in the stomach and you flex your abdominals to break the pressure.Thoracic cavity increases in size and volume of lungs expand during inhalation. Thoracic cavity decreases in size and lungs recoil during exhalation.Physical factors influencing ventilation: airway resistanceoofriction is the major NONelastic source of resistance to air flowomucous is a resistance to airflow because it will reduce the diameteroAir flow is directly related to the difference in pressureoAir flow is inversely related to the tube resistance (diameter accounts for this)oThe smaller the diameter = the bigger the resistanceoCan NOT change the diameter of the BIG tubes with cartilageoSMALLER tubes have smooth muscle so you CAN change the diameter of those tubesBronchial dilationoThe amount of gas flowing into and out of the alveoli is directly proportional to the (delta P)Delta P = the pressure gradient between the atmosphere and alveolio** The greatest resistance is in the medium-sized bronchi **oAs airway resistance increases, breathing becomes more strenuousoSeverely constricted or obstructed bronchioles:Can prevent life-sustaining ventilationCan occur during acute asthmaAnatomical Dead Space and Tidal Volumeotidal volume: (500-600mL) they look like small waves at the beginning. It is the air we move in and out during normal respiration at rest. The waves are equal size.oAnatomical dead space: volume of the conducting respiratory passages (150 mL)ooIn yellow is the conducting zone or anatomic dead space (150 mL)oStays in conducting zone and does NOT participate in gas exchangeoIn blue is the respiratory zone or alveolar air (350 mL)Alveolar VentilationoAlveolar ventilation rate (AVR) measure flow of fresh gas into and out of the alveoli during a particular timeoAVR= frequency x (TV-dead space)5250 ml = (15breaths/min) X (350ml/breath)Slow, deep breathing increases AVRRapid, shallow breathing decreases AVRo**We take about 12-15 breaths in 1 minute.**Basic Properties of Gases: Dalton’s Law of partial pressuresTotal pressure exerted by a mixture of gases is the sum of the pressures exerted independently by each gas in the mixturePartial pressure of each gas is directly proportional to its percentage of the mixture-Partial pressure = % concentration X total pressureAir is made up of O2, CO2, and N2-Most abundant gas is nitrogen, most important in oxygen-Oxygen moves outside air to alveoli-Co2 moves air from alveoli to outside.oHenry’s Law: more gas molecules are soluble at higher pressureoPartial Pressure Gradients and Gas Solubility’sCarbon dioxide has a lower partial pressure gradient; however:-It is 20 times MORE soluble than oxygen-It diffuses in EQUAL amounts with oxygenoCO2 only needs about 5 mm of pressure to moveoOxygen needs about 60 mm of pressure to moveoThe pressure in the alveolus always stays the same.othe pressure in blood will continue to rise, so the diffusion is less. oOnce the blood pressure and alveolus pressure difference is 0, there is no diffusion. (reached equilibrium)3 important continuous processes are responsible for the movement of O2 and CO21) Ventilation- moves gas into and out of the lungs2) Gas Exchange- moves gas into and out of the bloodOccurs at the lungs (blood surrounding lungs) = external respirationAnd at the tissue = internal respiration3) Gas transportBlood gases are transported to the organs and tissues (systemic circulation)Blood gases are
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