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Criado por Aalia Mohammad
2 meses atrás
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Questão | Responda |
what do humans obtain and what do they expel? and why is it important? | -humans obtain oxygen and expel carbon dioxide. -important because it supplies body with oxygen for aerobic cellular respiration. and also helps eliminate CO2 produced during aerobic cellular respiration. |
what is external respiration? | -gas exchange between air and blood (lungs). |
what is internal respiration? | -gas exchange between blood and tissue fluid (body) |
what is cellular respiration? | -ATP production C6H12O6 + 6O2 ---> 6CO2 + 6H2O + 36 ATP |
describe the nose in the upper respiratory tract. | -also known as nasal cavity. -site of air intake -conditions air by filtering, moistening and warming it. |
describe the pharynx in the upper respiratory tract. | -tube from mouth to beginning of trachea. -carries both food and air. |
describe the epiglottis in the lower respiratory tract. | -flap like structure composed of cartilage but remains flexible. -closes of trachea when food and liquid is ingested. |
describe the larynx in the lower respiratory tract. | -also known as voice box and is the opening of the trachea -holds vocal cords in place (Adam's apple) |
describe the trachea in the lower respiratory tract. | -air passageway to lungs -held open by cartilage rings -lined with ciliated mucus membrane -protects lungs from foreign debris by first trapping it and then sweeping it up |
describe the bronchi in the lower respiratory tract. | -the trachea branches into 2 smaller bronchioles. -these tubes have small muscle and no cartilaginous rings. |
describe the alveoli (external respiration) | -bronchioles end in groups of sacs (alveoli) -each alveolus is only 1 layer of epithelial cells. -gas exchange occurs between the alveoli and the lung capillaries. -alveoli make up most of the lung tissue -alveoli secretes lipoprotein to surface tension so they don't close. -highly vascularized to increase rate of exchange. |
what are the 2 external structures? | -pleural membranes -diaphragm |
describe pleural membranes | -2 membranes- 1 side sticks to lung, other side to thoracic (chest) cavity. -thoracic cavity enclosed by ribs, spinal column, sternum and muscles. -pleural membranes (and pleural fluid in between) prevents lungs from collapsing. -if air gets into pleural space, lungs will collapse. |
describe the diaphragm | -large dome shaped muscle located directly below the lungs and heart. -major muscle of respiration. -contracts and flattens during inhalation forcing air into the lungs. -relaxes and curves during exhalation. |
what is the purpose of ventilation aka breathing? | -to expel old air and to inhale new air into your lungs. it is a 2-step process. |
what is air intake referred to as? | -inhalation or inspiration |
what is air outflow referred to as? | -exhalation or expiration. |
is breathing controlled? | -usually breathing is controlled unconsciously by the respiratory center in the medulla oblongata |
what do triggers do? | -they tell the body when to start inhaling and when to stop. |
what are the 2 primary triggers? | 1) blood pH (indirectly measures CO2) 2) stretch receptors in alveoli (nerves) |
describe triggers. | -low oxygen levels in the blood are not the primary trigger; but high [CO2] is! -O2 levels are a secondary trigger -O2 & CO2 levels are detected by carotid bodies and aortic bodies, & specialized receptor nerve cells. |
describe blood pH | -most carbon dioxide is carried in the form of bicarbonate (H2CO3) in the blood. CO2 + H20--> H2CO3--> H+ + HCO3- -Bicarbonate dissociates into H+ ions decreasing blood pH -when blood pH is too low, medulla oblongata is stimulated. -increased blood acidity results in an increased breathing rate. |
describe stretch receptors | -once lungs expand, stretch receptors in alveolar wall are stimulated and send impulses to brain that signal us to stop inhaling. -medulla oblongata then sends nerve impulses to chest and diaphragm, causing exhalation. |
describe the mechanics of breathing. | -inhaling and exhaling is based on creating differences in pressure. -fluids like air move from high pressure areas to low pressure areas. -when you suck a straw, you are creating a negative pressure. -the pressure on the fluid then pushes the drink into your mouth. |
Describe inspiration (inhalation) | -diaphragm contracts and lowers. -rib muscles (intercostals) contract, and rib cage expands upward, and outwards. -chest cavity size increases. pleural membranes bring lungs with them, so lungs expand. -creates lower pressure in alveoli -now lungs have a negative pressure with respect to the atmosphere. -allows air to rush into lungs. |
describe expiration (exhalation) | -diaphragm relaxes (moves upward) -intercostals relax; rib cage moves down and inward. -lungs become smaller; air is pushed out of lungs (due to positive pressure in lungs). |
what is dead space? | -dead space: air in respiration tract where no gas exchange occurs (trachea, bronchi, alveoli etc.) -not all inhaled air leaves the lungs, or they would collapse. the lower intrapleural pressure keeps the lungs inflated |
what is residual air? | -the volume of air left in lungs after expiration. |
what is vital capacity? | -maximum amount of air you can inhale and exhale in one breath |
what is tidal volume? | -the volume of air that goes in and out in a normal breath (250-350 ml). |
what is inspiratory and expiratory reserve volume? | -maximum amount of air that can be inhaled or exhaled voluntarily. |
where is external transport & exchange of C02 and O2? | between environment and lungs |
where is internal transport & exchange of C02 and O2? | between blood and cell. |
explain external respiration in the lungs | -gas moves as a result of the concentration gradient - increase [O2] in alveolus causes diffusion of O2 into pulmonary capillary. -high [CO2] in capillary causes diffusion of CO2 into alveolus. |
explain internal respiration in the tissues. | -O2 is lower in the tissues because it is used up during aerobic cellular respiration. -therefore, O2 diffuses into the tissues. -CO2 is higher in the tissues than the blood, so it diffuses from the tissues into the capillary. |
what are the 3 conditions affecting % of O2 saturation of Hb? | -partial pressure -temperature -pH |
what is the effect of partial pressure on %O2 saturation of Hb? | -Hb releases O2 at low O2 pressure. (tissues) -Hb binds with O2 at high O2 pressure (lungs) |
what is the effect of pH on %O2 saturation of Hb? | -in basic environment of the lungs it is easier for O2 to attach to the hemoglobin -in the slightly more acidic tissues, O2 is released. |
what is the effect of temperature on %O2 saturation of Hb? | -O2 binding with hemoglobin is facilitated in cooler environments. -as temp increases, it is released. -temp in the tissues is warmer than in the lungs. |
describe Oxygen's relation with Hemoglobin. | -most 02 is carried by Hb on RBC's -w/o Hb, blood could only carry 1/60th amount of O2. -O2 combines with iron portion of Hb -Hb is a quaternary protein -each Hb can carry up to 4 O2 molecules -each RBC has 270 million Hb molecules. |
describe carbon monoxide (CO) | -is a competitive inhibitor. called carbon monoxide poisoning. -CO can bind with Hb almost irreversibly preventing O2 binding -only treatment is 100% oxygen. |
describe the mechanisms of respiratory disorders (diseases). | -functional unit of the lung is alveolus -structure of alveolus gives the lungs an enourmous amount of surface area. -reduction of surface area will reduce the efficiency of gas exchange and will result in reduced blood oxygen. |
describe bonchial asthma. | -flow of air through bronchioles & bronchi obstructed -may be due to narrowing of bronchi or amount of fluids in bronchioles -may be genetic, by allergic response, or environmental pollution. -treated with medication which causes bronchioles to dilate |
describe pulmonary tuberculosis. | -caused by mycobacterium tuberculosis infection -immune system creates clusters of cells called tubercles to surround & kill bacteria -bacteria spreading = more tubercles -gas exhange cannot occur at tubercles. -can lead to permanent damage and is contagious. |
describe pulmonary edema | -caused by high BP in pulmonary capillaries -results in fluid being pushed into alveoli -interferes with gas exchange at alveoli -common causes are heart disease or high altitude. |
describe emphysema | -alveoli are damaged by particles from smoke or pollution -surface area of lungs is reduced -results in damaged alveoli not working properly and old air becomes trapped leaving no room for fresh air to enter. |
describe pneumonia | -bacterial or viral infection -results in buildup of fluids in alveoli -affects people with weak lungs (smokers, elderly) |
describe cystic fibrosis | -genetic disorder caused by one of many different mutations in the CFTR gene. -usually associated with sticky mucus that plugs airways and alveoli. -average life span with CF is 48 years |
describe lung cancer | -most common in males. number 1 cause of death in both sexes -85% of lung cancer is linked to smoking -can lead to blockage of airways or spread of cancer in body. |
in which 3 ways does transport of carbon dioxide happen? | - a small amount of CO2 dissolves in the plasma -some CO2 is carried by hemoglobin -most of CO2 combines with H2O and its transported in blood plasma and is dissolved as a bicarbonate ion. |
what does carbonic anhydrase do? | -it speeds up the rxn, ensuring a net movement of CO2 from tissues to blood |
how would H+ affect the blood? | -H+ would change blood pH too much -H+ helps dislodge O2, so it can move into the tissues and attach to the Hb to form reduced Hb, therefore Hb acts as a buffer. -at the lungs H+ & CO2 are both disloged from Hb by O2. - H+ recombines with HC03- to form CO2 & H20. |
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