Anatomy and Physiology Exam 4 FINAL Figueroa Respiratory System Mechanics of breathing Pulmonary ventilation o Inspiration air flows into lungs Move fresh air IN to the body to the alveolus o 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 into the lungs o 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 o Considered conducting zone because NO alveoli so no actual gas exchange occurs in the conducting zone o Move air Bronchi Subdivided into Secondary Bronchi each supplying a lobe of the lungs There are 23 orders of branching in the lungs that air must pass through Big tubes contain cartilage small tubes lack cartilage o Cuboidal epithelium smooth muscle o CONSISTS of Trachea Primary bronchi Tertiary bronchi Bronchioles Respiratory Zone HAVE alveoli terminal bronchioles feed into respiratory Secondary bronchi bronchioles o Terminal bronchioles o Respiratory bronchioles o Alveolar ducts o Alveolar sacs o 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 exchange o Capillaries cover alveoli o 6 capillaries cover the alveoli Air blood barrier o Composed of alveolar and capillary walls o Fused basal laminas o O2 diffuses into the cell and CO2 diffuses out of the cells o There is liquid in between the lungs and the blood capillaries Alveolar walls o Epithelial cells o Permit gas exchange by simple diffusion o Secrete ACE which converts to angiotensin 1 and 2 Pressure relationships in the thoracic cavity Air flow is the difference in pressure so we change our thoracic pressure o always described in atmospheric pressure Patm o Patm is exerted by air surrounding body so therefore o negative respiratory pressure is less than Patm o leads to inhalation so air can go from high pressure outside of body to low pressure inside the body o positive respiratory pressure is greater than Patm o leads to exhalation so air can go from high pressure inside the body to low pressure outside the body o Patm 760 mm at sea level o think that pressure always go from high to low o Inhalation and exhalation are same as inspiration expiration o Main muscle is the diaphragm o When diaphragm contracts it comes down Inspiratory Move air in high to lower pressure thoracic cavity There is more pressure o think of taking a deep breath In you are elongating your body and o When we relax the diaphragm it will go up thoracic cavity gets smaller o The 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 resistance o o friction is the major NONelastic source of resistance to air flow o mucous is a resistance to airflow because it will reduce the diameter o Air flow is directly related to the difference in pressure o Air flow is inversely related to the tube resistance diameter accounts o The smaller the diameter the bigger the resistance o Can NOT change the diameter of the BIG tubes with cartilage o SMALLER tubes have smooth muscle so you CAN change the diameter for this of those tubes o The amount of gas flowing into and out of the alveoli is directly Delta P the pressure gradient between the atmosphere and Bronchial dilation proportional to the delta P alveoli o The greatest resistance is in the medium sized bronchi o As airway resistance increases breathing becomes more strenuous o Severely constricted or obstructed bronchioles Can prevent life sustaining ventilation Can occur during acute asthma Anatomical Dead Space and Tidal Volume o tidal 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 o Anatomical dead space volume of the conducting respiratory passages 150 mL o o In yellow is the conducting zone or anatomic dead space 150 mL o Stays in conducting zone and does NOT participate in gas exchange o In blue is the respiratory zone or alveolar air 350 mL Alveolar Ventilation o Alveolar ventilation rate AVR measure flow of fresh gas into and out of the alveoli during a particular time o AVR frequency x TV dead space 5250 ml 15breaths min X 350ml breath Slow deep breathing increases AVR Rapid shallow breathing decreases AVR o We take about 12 15 breaths in 1 minute Basic Properties of Gases Dalton s Law of partial pressures Total pressure exerted by a mixture of gases is the sum of the pressures exerted independently by each gas in the mixture Partial pressure of each gas is directly proportional to its percentage of the mixture Partial pressure concentration X total pressure Air 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 o Henry s Law more gas molecules are soluble at higher pressure o Partial Pressure Gradients and Gas Solubility s Carbon dioxide has a lower partial pressure gradient however It is 20 times MORE soluble than oxygen It diffuses in EQUAL amounts with oxygen o CO2 only needs about 5 mm of pressure to move o Oxygen needs about 60 mm of pressure to move o The pressure in the alveolus always stays the same o the pressure in blood will continue to rise so the diffusion is less o Once 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 CO2 1 Ventilation moves gas into and out of the lungs 2 Gas Exchange moves gas into and out of the blood Occurs at the lungs blood surrounding lungs external respiration And at the tissue internal respiration 3 Gas transport Blood gases are transported to the organs and tissues systemic circulation Blood gases are transported to the lungs pulmonary circulation Gas exchange o at the lungs gas exchange occurs between the alveolar and
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