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28 Cards in this Set
- Front
- Back
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What are the respiratory gases?
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1) Oxygen (O2)
2) Carbon dioxide (CO2) |
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Tell me O2 and CO2...
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- Oxygen: cells require O2 from the environment to produce ATP by cellular respiration
- Carbon Dioxide: cellular respiration produces CO2 as an end product, which must be lost to the environment to prevent toxic effects |
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What is the only means to exchange these gases?
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Diffusion
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Tell me about animals that have no internal transport of O2…
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1) Severely limited in size OR
2) Have evolved bodies that are flattened or built around a central cavity |
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What is Fick’s law of diffusion and what does each letter represent?
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Q = DA (P1 - P2/L)
- Q = rate - D = the coefficient - A = area - P1 and P2 = the partial pressures - L = distance |
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What are lungs and why are they highly divided?
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Internal cavities for gas exchange in air breathers
> Divided to provide greater surface area and are elastic to permit inflation and deflation |
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What are tracheae and how do they function?
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A unique system of branched tubules used for gas exchange
> They penetrate through fine terminal branches to tissues and cells, presenting an enormous surface area for gas exchange |
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How is driving diffusion of gases across gas exchange membranes (i.e., maximizing the partial pressure gradients—(P1 – P2)/L in Fick’s law) accomplished?
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Thin membranes shorten the diffusion path (L)
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What are spiracles?
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1) Openings on the outside of insect bodies that admit air
2) Where the tracheae begin |
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Some insects that stay under water for extended periods carry a bubble of air with them. How does this work?
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Even when the O2 lowers in the bubble, more diffuses in from the water, giving them nearly limitless time underwater
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In fish, water passes into the mouth, over the gills and out the opercular flaps. How does this work?
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1) The gills maximize the surface area for gas exchange (A)
2) The perfusing blood flow on the inner surface of the lamellae is UNIDIRECTIONAL |
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Birds can sustain high activity levels much longer and at higher altitudes than mammals can. Describe the flow of air through the lungs in birds…
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1) Air flows unidirectionally through the lungs rather than in and out via the same airway as in mammals
2) Birds also have air sacs in the body that are connected to the lungs, but are not gas exchange surfaces 3) The bronchi divide into parabronchi that run parallel to one another 4) Branching from the parabronchi are air capillaries where gas exchange occurs |
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What does the air pathway in humans consist of?
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1) An oral or nasal cavity, followed by the…
2) Pharynx 3) Larynx, which leads to the… 4) Trachea |
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What is the pharynx and the larynx?
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- Pharynx = an area for both food and air
- Larynx = voice box |
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Tell me about the trachea…
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1) Branches into two bronchi (both of these have cartilage support)
2) The bronchi branch repeatedly into bronchioles, which terminate in the alveoli |
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What are alveoli?
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Thin-walled air sacs and are the sites of gas exchange
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What are two adaptations that aid the breathing process in mammals?
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1) Mucus
2) Surfactants |
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What is the function of mucus and what is a surfactant?
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- Mucus: captures dirt and microbes
- Surfactant = a chemical substance that reduces the surface tension of a liquid (ex. bleach or soap) |
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What are the human lungs suspended in and what is it bounded by?
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The thoracic cavity in separate, closed pleural cavities
> Bounded by the: 1) Shoulder girdle 2) Rib cage 3) Diaphragm |
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What is the function of the intercostal muscle?
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They lift the ribs up and down to increase thoracic cavity volume
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What is the function of external and internal intercostal muscles?
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- External: expand the thoracic cavity and increase the volume of air inhaled
- Internal: decrease the volume of the thoracic cavity and increase the amount of air exhaled |
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What does breathing involve?
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Changes in volume of the thoracic cavity
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What does an increase in its volume create?
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Negative pressure (suction) inside the pleural cavity
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What happens between breaths?
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There is a slight negative pressure inside the pleural cavity keeping the alveoli partially inflated
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What happens with inhalation and exhalation?
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- Inhalation: the diaphragm muscle contracts downward to create suction, and air flows into the lung
- Exhalation: the diaphragm muscle relaxes and pushes upward |
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What is Hemoglobin?
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1) A protein consisting of four polypeptide subunits, each with a heme (iron-containing) group
2) Each heme group can reversibly bind a molecule of O2 |
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What happens as O2 diffuses into the blood?
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It binds to hemoglobin, increasing the PO2 gradient and driving diffusion of O2 into red blood cells
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Tell me about carbon monoxide (CO)…
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1) CO binds to hemoglobin with a much higher affinity than does O2
2) CO is a deadly poison, as it destroys the ability of hemoglobin to transport O2 |
