Structure and Function of the Respiratory System PDF

STRUCTURE AND FUNCTION OF THE RESPIRATORY SYSTEM Let’s see what you know about the respiratory system already!  Take the short quiz posted on Google Classroom on the respiratory system Did you know??  You breathe in and out an average of 15 times/minute – Let’s try it out!  The a...

STRUCTURE AND FUNCTION OF THE RESPIRATORY SYSTEM Let’s see what you know about the respiratory system already!  Take the short quiz posted on Google Classroom on the respiratory system Did you know??  You breathe in and out an average of 15 times/minute – Let’s try it out!  The average person moves more than 10 000L of air in and out of their lungs each day  Your right lung is slightly larger than the left…Why??  The highest recorded sneeze speed is 165 km/h!  The surface area of the lungs is roughly the same size as a tennis court  The breathing rate in women and children is faster than in men. Why?  When you yawn, more oxygen goes into your lungs. All living things need to respire Why do living organisms need a respiratory system?  Need O2 in:  for cellular respiration  make ATP (from carbs, proteins and fats)  Need CO2 out:  waste product  C6H12O6 + 6O2  6H2O + 6CO2 + 36ATP Transferring Gases To and From Cells  In animals with lungs (humans), the transfer of gases from the environment into the body and to the cells occurs in 3 phases: 1) Breathing 2) Transport of gases 3) Exchange of gases in cells Diffusion  It is the passive movement (does not require energy) of particles from high to low concentration. Ex. Oxygen, glucose, carbon dioxide, waste, etc. Diffusion in the Respiratory System  Diffusion controls the movement of respiratory gases into and out of the body (along the respiratory surface)  Movement of gases (O2 and CO2) from areas of high concentration to low concentration Respiratory Surfaces Must have certain features to ensure efficient diffusion of respiratory gases: 1) Thin and moist membrane that is permeable to the gases being diffused 2) Large surface area to have maximum area for diffusion 3) Concentration gradient present (areas of high and low concentrations of O2 and CO2) Respiratory Surfaces  Single celled organisms don’t have breathing organs and use their cell membranes to respire.  Diffusion only works to move substances up to a few cell widths.  Ex. paramecium Diffusion isn’t enough…  A larger organism needs a gas exchange and transport system because it’s a complex organism that is multicellular. Breathing through skin  Body surface = respiratory surface (i.e. breathe through their skin)  Organisms that breathe through their skin are small or have flat bodies to provide a high ratio of respiratory surface to body volume  Live in damp places or water to keep entire body/respiratory surface moist  Ex. Earthworms, frogs, toads Gas Exchange in Aquatic Animals – Gills Gills are gas exchange membranes (thin tissue) outside body:  high surface area  must stay wet  diffusion of gases (aqueous) Gills have lots of blood vessels for gas exchange:  O2 into blood  CO2 out to water Gas Exchange in Terrestrial Animals Advantage:  Higher concentration gradient for oxygen in air vs. water therefore less energy spent in exchanging gases along respiratory surface *fish must constantly swim around to get enough O2-rich water Disadvantage:  Loss of moisture – evolution of internal respiratory system to minimize moisture loss Gas Exchange in Terrestrial Animals – Tracheal System  Common in insects, don’t have lungs MADAGASCAR HISSING COCKROACH  https://www.youtube.com/watch?v=W7Efjt6UC1g  Will expel air through spiracles to scare off predators, while fighting, during courtship and mating – Hissing noise (larger males can hiss louder – natural selection) Gas Exchange in Terrestrial Animals – Lungs  Internal respiratory system structures are surrounded by fluids/moist tissues and blood vessels where gas exchange occurs