1 / 11

The Respiratory System and Gas Exchange in Animals

This chapter discusses the evolution and mechanics of the respiratory system, the process of gas exchange, and the control of respiration in animals. It also covers common respiratory disorders such as asthma. Learn more with online quizzes.

dodsons
Download Presentation

The Respiratory System and Gas Exchange in Animals

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Respiratory SystemChapter 42Campbell & Reece

  2. Respiration: exchange of O2 for CO2 Two kinds: • Cellular Respiration: mitochondria --> ATP... (Chapter 7) • Uses O2 to turn glucose into energy (by-product is CO2) • Organismal Respiration: exchange of gases between cells and environment (Chapter 47) • Involves the exchange of O2CO2 between cells/blood/lungs

  3. Evolution of the Respiratory System: • Earliest animals simply diffused O2 through their skin • Insects = use "tracheae" (cuticle-lined tubules in abdomen) good for small animals only • First evolved respiratory organs were GILLS; probably arose as a feeding device, originally • Thin, one cell thick membranes; folded, layered (high surface area); increase respiratory surface; bring more blood in contact w/ O2 • "Counter Current Exchange": circulatory vessels are arranged so blood is pumped through in opposite direction of water flow (O2). Maximizes O2 pickup. • LUNGS- internal cavities, also made of many thin, folded air sacs for lots of surface area (better gas exchange) • More efficient than gills (21% O2/Air, 0.5% O2 in Water) • Fish must process more H2O to get the same amount of O2 as in Air (Energy-Consuming)

  4. Respiration in Large/Complex Animals • STEP 1: "Bulk-flow" of air into lungs (thin, close to blood vessels) • STEP 2: Diffusion of O2 across membrane into blood  animation • STEP 3: passage of O2 from blood into tissues • STEP 4: Diffusion of O2 into individual cells

  5. Diffusion and Air Pressure • Oxygen enters the blood/tissues/cells enters blood via diffusion (from areas of high concentration to low) • If there’s more O2 in the air we breathe, it should diffuse into your red blood cells • Gas Exchange depends upon pressure and concentration differences between atmosphere and bloodstream • changes in the partial pressures of oxygen and carbon dioxide affect diffusion:  animation • Atmospheric pressure (mm Hg)  affects O2 diffusion into blood/tissues (higher altitude, lower pressure) • How does this affect our breathing at altitude?

  6. The Human Respiratory System • Nasal passages (mucus,cilia) • Pharynx • Epiglottis • Larynx • Trachea • R&L bronchi • Bronchioles • Alveoli (alveolus) are tiny air sacs with thin walls (surrounded by capillaries) • gases exchanged through capillary/alveolar walls via diffusion A thin Pleural Membrane encases lungs, secretes lubricants (mucus)

  7. Alveoli

  8. Asthma • Smooth Muscles can dilate/constrict the bronchi, bronchioles • Asthma is a chronic disease that affects your airways • the inside walls of your airways become inflamed (swollen) and clogged with mucus • The inflammation makes the airways very sensitive, and they tend to react strongly to things that you are allergic to or find irritating. • When the airways react, they get narrower, and less air flows through to your lung tissue. • This causes symptoms like wheezing (a whistling sound when you breathe), coughing, chest tightness, and trouble breathing, especially at night and in the early morning.

  9. Mechanics of Respiration: • Breathing- due to pressure changes w/in thoracic cavity • muscles: • Diaphragm • relaxes--> rises • contracts--> lowers • Abdominals/ Intercostals raise and lower the ribcage to adjust volume of thoracic cavity • http://health.howstuffworks.com/adam-200020.htm • Inspiration -vs- Expiration • breathing animation

  10. Transport and Exchange of Gases A. HEMOGLOBIN – • respiratory pigment • oxygen-carrying protein molecule w/ central iron (Fe) atom • Mollusks & Arthropods: “hemocyanin”, blue w/ O2 • heme carried on RBC, can carry 4 Oxygen molecules each (O2 not very soluble in plasma) • Most CO2 is carried in the plasma as (1) carbon anhydrase (in RBC); or (2) carbonic acid; or (3) bicarbonate ion (HCO3) B. MYOGLOBIN- respiratory pigment found is skeletal muscle • has higher O2 affinity than hemoglobin • O2 reserve for muscles under stress • "Diving Reflex" in marine mammals

  11. Control of Respiration • Respiration is under control of brainstem (medulla) • Involuntary, but can be brought under voluntary control temporarily • Many "sensors" located throughout body that give feedback to brain resp. centers • sensors sensitive to CO2, O2, H+ levels • stretch sensors in lungs & chest • chemoreceptors in Carotid Arteries detect blood pH ex: low pH (acidic) = high CO2 levels, breathing becomes faster/deeper Practice!  online quizzes: Respiratory system anatomy http://msjensen.cehd.umn.edu/webanatomy_archive/wa_respiratory/wa_resps_1.html

More Related