Ch 22- Respiration- The Exchange of Gases
description
Transcript of Ch 22- Respiration- The Exchange of Gases
![Page 1: Ch 22- Respiration- The Exchange of Gases](https://reader035.fdocuments.in/reader035/viewer/2022062520/56816584550346895dd82e37/html5/thumbnails/1.jpg)
Ch 22- Respiration- The Exchange of Gases• Alveoli• Breathing control centers• Bronchi• Bronchioles• Countercurrent exchange• Diaphragm• Emphysema• Gas exchange• Gills• Hemoglobin• Hyperventilating• Larynx
• Lungs• Negative pressure breathing• Partial pressure• Pharynx• Respiration• Respiratory surface• Trachea• Tracheae• Tracheoles• Ventilation• Vital capacity• Vocal cords
![Page 2: Ch 22- Respiration- The Exchange of Gases](https://reader035.fdocuments.in/reader035/viewer/2022062520/56816584550346895dd82e37/html5/thumbnails/2.jpg)
Gas exchange
• Gas exchange- interchange of O2 and CO2 between an animal and it’s environment
• Mechanisms:– Breathing– Gases transported by circulatory system to body– Tissues take up O2 and release CO2 to the blood
• Animals exchange gases through moist body surfaces– Respiratory surfaces- must be wet to function properly, thin for O2 and
CO2 to diffuse easily
![Page 3: Ch 22- Respiration- The Exchange of Gases](https://reader035.fdocuments.in/reader035/viewer/2022062520/56816584550346895dd82e37/html5/thumbnails/3.jpg)
Respiratory Surfaces• Entire outer skin- ex: earthworm• Gills- for exchange in water
– Opening and closing of mouth and gills allows for increase in gas exchange efficiency (ventilation)
– Countercurrent flow of water enhances O2 transfer (80% can be removed!!!)
![Page 4: Ch 22- Respiration- The Exchange of Gases](https://reader035.fdocuments.in/reader035/viewer/2022062520/56816584550346895dd82e37/html5/thumbnails/4.jpg)
Countercurrent exchange
![Page 5: Ch 22- Respiration- The Exchange of Gases](https://reader035.fdocuments.in/reader035/viewer/2022062520/56816584550346895dd82e37/html5/thumbnails/5.jpg)
Respiratory Surfaces• Tracheal system- branching air tubes in body (tracheae) opens
to outside, narrowest-tracheoles- extend to nearly every cell in body
• * terrestrial animals spend less E on getting O2 because air is lighter and has more O2)
• Lungs- most terrestrial vertebrates
![Page 6: Ch 22- Respiration- The Exchange of Gases](https://reader035.fdocuments.in/reader035/viewer/2022062520/56816584550346895dd82e37/html5/thumbnails/6.jpg)
Human respiratory system
![Page 7: Ch 22- Respiration- The Exchange of Gases](https://reader035.fdocuments.in/reader035/viewer/2022062520/56816584550346895dd82e37/html5/thumbnails/7.jpg)
Human respiratory system• Air enters through nostrils- warmed, humidified and sampled• Pharynx- throat• Larynx- voice box- air rushing over cords creates sound• Trachea- windpipe- has rings of cartilage to maintain open
shape• Bronchi- 2 tubes, 1 to each lung• Bronchiole- get thinner and finer branching within lung• Alveoli- air sacs, end of branching, covered in capillaries,
where gas exchange takes place• Cilia and mucous throughout system- clean air • Diaphragm- muscle at bottom of chest cavity, facilitates
breathing
![Page 8: Ch 22- Respiration- The Exchange of Gases](https://reader035.fdocuments.in/reader035/viewer/2022062520/56816584550346895dd82e37/html5/thumbnails/8.jpg)
Breathing• Alternating inhaling and exhaling
– Diaphragm contracts, rib cage expands= air rushes in– Diaphragm relaxes, rib cage lowers= air’s pushed out– Negative pressure breathing- muscle contraction causes lower
pressure inside than outside and air rushes in– Vital capacity- max volume of air we can breathe in & out
![Page 9: Ch 22- Respiration- The Exchange of Gases](https://reader035.fdocuments.in/reader035/viewer/2022062520/56816584550346895dd82e37/html5/thumbnails/9.jpg)
Breathing
![Page 10: Ch 22- Respiration- The Exchange of Gases](https://reader035.fdocuments.in/reader035/viewer/2022062520/56816584550346895dd82e37/html5/thumbnails/10.jpg)
Controlling Breathing• Pons and medulla oblongata –
breathing control center• Nerve signals sent to contract
diaphragm and raise ribs by contraction of muscles
• Medulla monitors CO2 levels and regulates breathing in response, also monitors blood pH, cerebrospinal fluid and O2 levels in large arteries and when O2 levels in blood are severely decreased
• pH decreases when CO2 increases
![Page 11: Ch 22- Respiration- The Exchange of Gases](https://reader035.fdocuments.in/reader035/viewer/2022062520/56816584550346895dd82e37/html5/thumbnails/11.jpg)
Hyperventilation
• Shows how control center works• Purge blood of CO2 so there is a temporary signal to
stop breathing (b/c of low CO2 levels)
![Page 12: Ch 22- Respiration- The Exchange of Gases](https://reader035.fdocuments.in/reader035/viewer/2022062520/56816584550346895dd82e37/html5/thumbnails/12.jpg)
Circulation of gases
• O2 rich blood in lungs goes to heart to be pumped to body
• O2 poor blood in body goes to heart to be pumped to lungs to pick up O2
• Gas exchange occurs by diffusion• Hemoglobin- O2 carrier in RBC’s
– 1 hemoglobin can carry 4 O2 molecules– Fig 22.11A and B in text– CO2 forms H2CO3 (carbonic acid) in RBC’s it breaks to HCO3-
(bicarbonate ion) and H+ (which hemoglobin takes up so that blood doesn’t become acidic)• In lungs- reaction is reversed HCO3- binds with H+ then H2CO3 is
converted to CO2 and H2O which is diffused into alveoli
![Page 13: Ch 22- Respiration- The Exchange of Gases](https://reader035.fdocuments.in/reader035/viewer/2022062520/56816584550346895dd82e37/html5/thumbnails/13.jpg)
CO2 transport in the blood
![Page 14: Ch 22- Respiration- The Exchange of Gases](https://reader035.fdocuments.in/reader035/viewer/2022062520/56816584550346895dd82e37/html5/thumbnails/14.jpg)
Gas exchange in fetus• Uses placenta for exchange from mothers blood from lungs• Fetal hemoglobin-special type that has higher affinity for O2
• At birth – increase in fetus’s CO2 level triggers breathing control center to start breathing
![Page 15: Ch 22- Respiration- The Exchange of Gases](https://reader035.fdocuments.in/reader035/viewer/2022062520/56816584550346895dd82e37/html5/thumbnails/15.jpg)
Problems in respiratory system• Asthma- bronchi become inflamed due to allergic
reaction• Bronchitis- inflammation of bronchi due to pathogens
(ex: bacteria)• Smoking!!- cilia and mucous trap particles and sweep
them out before reaching alveoli– Macrophages also engulf particles and microorganisms– Smoking destroys cilia and macrophages- allowing toxins to
reach alveoli – Fig 22.7A- lung cancer– Emphysema- alveoli become brittle and rupture, decreases gas
exchange (not enough oxygen)
![Page 16: Ch 22- Respiration- The Exchange of Gases](https://reader035.fdocuments.in/reader035/viewer/2022062520/56816584550346895dd82e37/html5/thumbnails/16.jpg)