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HUMAN RESPIRATORY STRUCTURES. Nose/mouth: filters, moistens, warms Pharynx Larynx Trachea – mucus, cilia 2 lungs 2 bronchi Bronchioles Alveoli Site of exchange Thin walls, lots-o-capillaries Large # S.A.
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HUMAN RESPIRATORY STRUCTURES • Nose/mouth: filters, moistens, warms • Pharynx • Larynx • Trachea – mucus, cilia • 2 lungs • 2 bronchi • Bronchioles • Alveoli • Site of exchange • Thin walls, lots-o-capillaries • Large # S.A.
A thin layer of mucus is produced on the lining of the tubes of the respiratory system This thin layer traps particles of dust or smoke These tubes are lined with CILIA that sweep away particles • These tubes are made of cartilage and are surrounded by smooth muscle
ALVEOLI • Small structures at the end of each bronchiole • Occur in clusters • Place where gas exchange occurs • Oxygen into blood, carbon dioxide into lung • Each is surrounded by capillaries • 300 million alveoli are in each healthy lung • Provides a large surface area for gas exchange • Oxygen dissolves in the moisture • It can then diffuse into the capillaries • CO2 diffuses in the opposite direction • Coated in surfactant
HEMOGLOBIN binds with so much oxygen that it increases the oxygen carrying- capacity of the blood more than 60 times
RECAP • Name the structures of the respiratory system • Where does gas exchange occur? • http://www.airinfonow.org/html/lungattack/lungplay.htm • Next: What is the difference between respiration and breathing?
Breathing is the movement of air into and out of the lungs Lungs sit in two sacs = pleural membranes At the bottom of the chest cavity is the diaphragm Between ribs are intercostal muscles Force that drives breathing is air pressure No muscles are directly connected to the lungs Breathing
Volume If you have a container of gas, how will the pressure change if you make the container smaller? Make it larger?
When you inhale, the diaphragm contracts and expands the volume of the chest cavity Because the chest cavity is tightly sealed, this creates a partial vacuum inside the cavity Air rushes into the lungs as a result Inhaling
Exhaling • Exhaling is a passive event • Diaphragm relaxes and lungs return to normal size, placing pressure on the lungs • Air rushes out of the lungs
Partial Pressure: “Concentration of Gas” 1) Volume: If you have a container of gas, how will the pressure change if you make the container smaller? Make it larger? Bulk Flow ~ Breathing 2) Total atmospheric pressure = 760mmHg Oxygen is 21% of this, therefore = 159mmHg O2 air > O2 alveoli > O2 blood > O2 cells 159mmHg 100mmHg 40mmHg 40mmHg (exchange to 100mmHg) Diffusion
RECAP • What causes breathing? • What muscles are involved with breathing? • Are they attached to the lungs? • What controls your breathing?
Breathing Control • Breathing is voluntary to a point, then it becomes involuntary • Nervous system will take over • Sensory receptors in major blood vessels detect amount of carbon dioxide in blood • b/c pH will change • Message goes to medulla oblongata in the brain • If the level of carbon dioxide gets too high, the diaphragm will contract
Oxygen in Blood 98.5% is bound to Hb 1.5% dissolved in plasma Carbon Dioxide in Blood 60% dissolves in H2O (as H2CO3) 30% binds to Hb 10% dissolves in plasma Carbon Monoxide Hb affinity 200 X’s stronger irreversible Hb + 4O2 “HbO”
REGULATION of pH • Normal plasma pH = 7.4 (Range: 7.35 - 7.45) CO2 + H20H2CO3H+ + HCO3- Waste product Always Converted to Waste product Buffer of metabolism Present Products on of metabolism LEFT by Carbonic Anhydrase ____________________________________________________________________________________________________ Expelled by Adjusted in kidney Lung Or Rxts w/Bicarb. R. Or Rxts w/H+ on L.
The exchange • http://www.airinfonow.org/html/lungattack/lungplay.htm • What can go wrong? • http://www.hisdbenefits.org/hisd/living/animations/ • List of animations for respiratory disorders • http://in.truveo.com/Human-Atlas-Emphysema/id/1459776665 • Similar animations, better quality
Diaphragm Contracts Intercostal Muscles relax Chest Cavity increases in size Pressure in cavity decreases Air rushes out of lungs Diaphragm relaxes Intercostal muscles contract Volume of chest cavity decreased Pressure inside greater Air rushes in and inflates lungs Breathing Quiz: Is it inhalation or exhalation?