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Download Respiratory System - BartlettsBiology11C
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Respiratory System Humans & Environment All animals exchange gases with their environment Animals take in oxygen (O2), release carbon dioxide (CO2) Process is called respiration Gases Oxygen Reacts with nutrients in mitochondria to release energy Carbon Dioxide Waste product as a result of these reactions Gases cannot be stored like nutrients can, so gases must be exchanged Endotherms Humans are large warm-blooded animals, with very high oxygen demand Define endotherm (page 219) Inhale Air is warmed, cleaned and moistened as it enters via mouth or nasal cavity Achieved by mucus and tiny hair Epiglottis (flap-like structures) covers the trachea when swallowing, opens when breathing Pathway Flowing down windpipe (trachea), air enters bronchi Bronchi divide into bronchioles (network of smaller tubes) Trachea, bronchi are supported by cartilage rings holding them open Goblet Cells Inner lining of trachea, bronchi and bronchioles lined with cilia and mucusproducing goblet cells Mucus traps tiny particles (bacteria, dust, pollen) carried out of lungs by sweeping action of cilia ‘Bronchiole Escalator’ Alveoli Bronchioles branch further into tiny air sacs called alveoli This is where gas exchange occurs Each lung has 150 million alveoli! Total surface area times your skin 40 Alveoli cont’d… Surrounding each air sac, is a capillary network…. Blood from the heart is pumped here to obtain oxygen O2 passes into capillaries via diffusion At the same time, CO2 diffuses out of the blood and into the lungs Oxygenated Blood How could you describe the blood leaving the lungs going back to the heart? How we breathe…
