Ch 46 Flashcards
respiration
the exchange of gases between an organism and its environment
organismic respiration
takes place in animals, O2 is taken up and CO2 is excreted
aerobic cellular respiration
takes place in mitochondria, O2 is needed for most ATP production
simple diffusion
passive movement of particles from a region of higher concentration to a region of lower concentration, provides gas exchange for small, aquatic organisms such as sponges, hydras, and flatworms (all invertebrates), this is the easiest way to get molecules that are in the environment and are needed into your body, diffusion is from high concentration to low concentration
What adaptations do living creatures have for gas exchange?
body surface, tracheae, gills, lungs
comparison of gas exchange in air and water
air: contains a higher concentration of molecular oxygen than water, oxygen diffuses more rapidly through air than water, less energy is needed to move air over a gas exchange surface; water: takes more work to move water, contains dissolved oxygen rather than molecular oxygen, it is 5 ppm (parts per million) oxygenated (if it’s less than 2ppm it’s a dead zone), fish breathe the dissolved oxygen-this is the reason the move around to keep in areas of 5ppm, if they stayed in the same place all the time the ppm would go down and there wouldn’t be enough oxygen
What is the difference between O2 and O?
O2 is molecular oxygen which is in the air, O is atomic oxygen which is unstable, there is also dissolved oxygen (DO) which is in water and which fish use to breathe
gas exchange across body surface
earthworms use their bodies to breathe by diffusing O2 across their skin
gas exchange across tracheal tubes
this type of gas exchange is found in insects, they don’t have lungs or gills, rather they have openings on their sides called spiracles where the air enters their tracheal tubes, the process is: spiracle–>trachea–>tracheole, air enters through the spiracles, then goes into the tracheal tubes that connect with tracheoles that are in direct contact with muscles, insects circulatory systems DO NOT carry oxygen, the air also leaves via the spiracles
How do fish’s respiratory systems work?
fish use their gills to breathe. The water has dissolved oxygen in it and it goes in the fish’s mouth and over its gills, as that water flows over their internal gills the oxygen (dissolved) is used, in fish the blood flows in the opposite direction that the water moves, this is called counter current gas exchange, it’s used so that the blood never has more oxygen than the water because if it did it would diffuse out of the fish which is the opposite of what we want, this way the oxygen is always coming in because the most oxygenated water is contacting with the most deoxygenated blood therefore causing diffusion of oxygen into the fish, fish have a gill arch, gill filaments, and lamellae: the filaments are the feathers of each gill and the lamellae are hills that are on the filaments
Which animal has the most effective lungs? Explain
Birds do. They have luns as well as posterior and anterior air sacs. Steps: 1) birds breathe into the posterior air sacs, 2) then as they breathe out, they breathe out into the lungs rather than into the environment, 3) they breathe in again and the air goes into the anterior air sacs, 4) as they exhale the 2nd time the air finally goes into the environment; 2 “sets” of air can be moving throughout their lungs/air sacs at the same time
What does the mammalian respiratory system include?
it includes the lungs and airways, the lung occupies the pleural cavity and is covered with a pleural membrane, the breath of air passes in a sequence: nostrils, nasal cavities, pharynx, larynx, trachea, bronchi, bronchioles, and alveoli
What is the order of body parts that a breath of air passes through?
nostrils, nasal cavities, pharynx, larynx, trachea, bronchi, bronchioles, and alveoli
Structure of alveoli
alveoli are extremely thin so that the oxygen we breathe can pass through into the blood, they are found in the lungs
How do frogs breathe?
frogs breath in air through their nose and fill up their mouth with the air (which is why their mouth expands so much), they then ‘swallow’ that air into their lungs, when they exhale they push the air back into their mouths from the lungs and then out their nose again; they also breathe through their skin because they don’t get quite enough oxygen from breathing the other way, use positive pressure
How do humans breathe?
we breathe by pulling air into our lungs, we also have a diaphragm muscle and rib muscles that help us to expand our chest to allow our lungs to expand and to inhale more oxygen
