Chapter 42 respiration circulation and blood 10 22 2015 Oxygen moves into body through simple diffusion Most organisms need oxygen not carbon dioxide Diffuse across a moist membrane how oxygen is obtained All of our cells are surrounded by fluid moist membrane Amphibians and earth worms can take in oxygen across their skin Terrestrial animals can t take in oxygen across skin Some respiratory medium air or water Respiratory surface o2 enters body through this o Outward oriented Respiratory structures outside of the organism o Inward oriented respiratory structures inside lungs Circulatory system Take oxygen into cells Used at the end of the ETC to generate ATP CO2 is a by product diffuses out of cell same way o2 came in Respiratory structures have 4 things in common 1 have to be moist 2 have a large surface area 3 have a way to get o2 to the rest of the cells of the body transport mechanism 4 have a way to protect them because they are delicate Examples of respiratory surfaces parapodia in marine worms used to walk and as respiratory surfaces gills constantly need to be watered so they work properly o countercurrent exchange MAXIMIZES DIFFUSION fish bring in water through mouth and then over gills to get oxygen out of the water concentration gradient giving up oxygen from water and bringing it into blood through gills can achieve about 80 o if went in the same direction could only get 50 because it would reach an equilibrium Terrestrial animals Most are inward oriented Two types of inward systems o Tracheal system large has to stay moist like the duct work that goes through a house found in arthropods branching throughout animals whole body Breaks off into tracheoles and air sacs Brings oxygen to all of the cells Limits how big the animal can be Movement of the flight muscles in larger insects help to move o2 and atp throughout the body o Lungs most primitive fish some land snails have a semi lung most amphibians reptiles birds and mammals Need a very rich blood supply FIG 42 25 Basal metabolic rate 4 parts to respiration 1 breathing air coming in bringing in o2 and going out to release co2 2 external respiration exchange o2 from air and letting it go into the blood 3 internal respiration going from the blood to the interstitial tissue fluid 4 cellular respiration making ATP from the oxygen cells are where we use all of the oxygen end of the ETC Parts of the Respiratory system External nares nostrils o Air comes in through the nasal cavity o First developed for smell not breathing o Separated into two cavities by a septum o Smell receptors o When air comes in several things happen 1 mucous lining moistens the air 2 hair and cilia on cells cleans the air 3 blood vessels lie directly under skin to warm the area vocal cords o elastic ligaments that vibrate to produce sounds o length thickness and elasticity affect how voices sound o testosterone has an affect on growth of vocal cords trachea o windpipe o cartilaginous rings for support to keep the tube from collapsing o will branch going to each side of the lungs bronchus bronchiole o lined with cilia that keep junk out of your lungs o moistens a little bit Alveoli o Little sac o At the end of the bronchiole o Only one cell o Diffusion isn t affective over long distances that s why there is only one cell doesn t want to move through a lot of o Very rich blood supply o Lined with film of a lipoprotein that reduces surface tension and keeps alveoli open o produced very late in embryonic development because there is fluid in the lungs for a long time when in mother s womb premature babies have a problem with this o pulmonary veins collect blood from capillaries collect blood and take it back to the heart o o2 that comes into lungs doesn t supply lungs with oxygen pleural membrane double wall sac one adheres to lung and one adheres to chest has some fluid if you get air in between it lungs with collapse how the lungs are ventilated carbon dioxide in blood and an increase in hydrogen ions makes an acidic environment and makes you breathe detected by centers in the hind brain primitive brain breathing control centers between Pons and Medulla oblongata back up system looks for lack of oxygen found in the aorta largest artery in the heart blood just coming back from lungs so should be very oxygenated and carotid go to the brain arteries chemoreceptors we breathe by negative pressure we don t force air into our lungs brain sends signals through nervous system down through ribcage into diaphragm o causes contraction of diaphragm so that your lungs and ribcage expand o increasing the chest cavity with expand the lungs making pressure fall o atmospheric pressure is higher and pressure moves from high to low so air will move into lungs reverses and ribcage gets smaller forcing air out FIGURE 42 49 Tidal air volume of air normally taken in during a single breath Vital capacity maximum volume of air that can be inhaled and exhaled during force breathing how much can lungs actually hold Residual volume the air that remains in the lungs after exhaling all that can be exhaled Birds are much more efficient at getting air Birds have air sacs Parabronchi replace alveoli Air flows in a circuit FIGURE 42 27 Because of air sacs birds get oxygen when inhaling and exhaling we only get oxygen in when inhaling CIRCULATION BABYYYYYY Two types of circulatory systems Open o o o o o o Arthropods most mollusks Surrounding all of these cells are sinuses open spaces Has a pump heart to move things through the body Hemolymph Interstitial fluid mixed with blood doesn t carry oxygen its in the tracheole system very slow closed o blood and interstitial fluid separated o blood always in tubes unless injury occurs o blood in vessels o pump heart that moves everything through o annelids cephalopods mammals o carrying nutrients oxygen hormones o blood system helps with temperature o have carbon dioxide moving through blood o nitrogenous waste that is sent to kidneys to be broken down 3 types of blood vessels artery o lead away from the heart o think walled layer of connective tissue elastic fibers in it important for expanding smooth muscle layer with connective fibers inner endothelial layer only one layer thick simple squamous and connective tissue blood pressure greatest in arteries in systemic plaque reduces volume and impedes flow of substances through arteries o lead to arterioles small arteries vein o lead toward the heart o same three layers in arteries but not as