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The Respiratory System. (Review) Cellular Respiration. Process by which energy from food molecules like glucose is transferred to ATP which is a usable form of energy to be used for cellular processes Takes place in the Mitochondria Also called “Internal Respiration”
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(Review) Cellular Respiration • Process by which energy from food molecules like glucose is transferred to ATP which is a usable form of energy to be used for cellular processes • Takes place in the Mitochondria • Also called “Internal Respiration” • Aerobic: when oxygen is present • Anaerobic: when oxygen supplies are low • Produces fewer ATP (2 instead of 36) • Produces lactic acid as a by product
Human Respiratory System • Function: • to exchange gases between the blood and the external environment • Also called “External Respiration” • Take in oxygen • Get rid of carbon dioxide • Excess water also removed
A system of passageways connects lungs to outside air and permits air to enter the lungs and wastes to leave Pathway that air follows: • Nose and Nasal Cavity • Pharynx • Larynx • Trachea • Bronchi • Bronchioles • Alveoli • Respiration Animation: • http://www.neok12.com/php/watch.php?v=zX7a51620305036844477802&t=Respiratory-System
Gases in the Bloodstream • Blood leaving lungs, high in oxygen • Blood entering lungs, high in carbon dioxide • Oxygen carried mainly by hemoglobin in RBCs • Carbon dioxide is dissolved in the blood plasma
Nose and Nasal Passages • Air enters and is warmed by blood flowing through capillaries near skin • Air is moistened and filtered by: • hairs lining nostrils • Cilia lining surfaces • Mucous secretions that trap dust, pollen etc… • The mucous and what it traps eventually dry out and form “boogers” • http://www.youtube.com/watch?v=1Fz5HiL0cgA&safe=active
Pharynx: (throat) • Passageway for the air as it travels on towards trachea • Food also passes through here • Larynx: • Contains the vocal cords, whose vibrations make speech possible • Clip showing woman’s vocal cords vibrating at high/low pitch: http://www.youtube.com/watch?v=UpOXecWC5Dw&safe=active
Trachea: • Connects the pharynx with the bronchi • Tube is rigidly supported by cartilaginous ridges • When swallowing, the epiglottis covers the trachea preventing food from entering the “windpipe”
Cleaning the Air We Breathe • Trachea and bronchiole tubes are lined with a ciliated membrane. • Mucous secretions trap particles • Cilia sweep foreign particles back up into the pharynx where they are swallowed or coughed up • http://www.youtube.com/watch?v=miEEluVlemQ&safe=active
Why do we Cough? • http://www.neok12.com/php/watch.php?v=zX066c555347077350076077&t=Respiratory-System
Bronchi: • 2 branches off trachea that enter the lungs • Bronchioles: • smaller and smaller tubes that eventually end in alveoli
Alveoli • The functional units for respiration in lungs • Thin walled sacs • one cell thick • Surrounded by capillary network
MicroAnatomy of the Lungs: Alveoli • http://www.neok12.com/php/watch.php?v=zX045c7b745d0a6d435f5245&t=Respiratory-System
Alveoli and Gas Exchange • Each alveolar sac is coated on the inside with a liquid called surfactant • This liquid surface is necessary for gas exchange to take place • Gas is exchanged by diffusion • Area of higher concentration to lower concentration • Type of passive transport • No energy required • Oxygen diffuses from alveoli into surrounding capillaries • Carbon dioxide and some water diffuses from capillaries into alveoli
The Respiratory System: How it Works (3:30) • http://www.neok12.com/php/watch.php?v=zX5a5b076c436a5b690d0373&t=Respiratory-System • Make a Lung/Diaphragm Model • http://www.youtube.com/watch?v=vRv2zYH5p9k&safe=active
Mechanism of Breathing Controlled by your nervous system and by muscles of the diaphragm and ribcage
Lungs have no muscle tissue and cannot move by themselves • They contract and expand due to pressure changes causes by the movement of the diaphragm and ribcage • Normal breathing rate = 12-25 per minute
Inhale: • Rib cage rises as rib muscles contract • Diaphragm muscle lowers as it contracts • Space in your chest cavity increases and creates a lower air pressure space (vacuum) that causes gas from outside to rush in to lungs
Exhale: • Ribcage lowers • Diaphragm goes up as it relaxes • Chest volume decreases • Increased pressure on air inside lungs forces most of it out of alveoli Breathing Animation: http://www.biotopics.co.uk/humans/inhexh.html
Control of Breathing • You can control it to some extent • Mostly it is an involuntary process • Controlled by respiratory center in the brain • in medulla oblongata
How does your body know to speed up breathing rate during exercise? • Chemoreceptors: • sensory tissue lining aorta and other large arteries sense amount of dissolved carbon dioxide in blood. • Send message to respiratory center in brain • Too much CO2 = breath deeper and more frequently
In addition the presence of lactic acid from heavy exercise can also stimulate the respiratory centers of the brain
Diseases of the Respiratory System • Asthma: • severe allergic reaction causes wheezing, coughing • bronchioles squeeze air passages closed during attack
Pneumonia: • alveoli become filled with fluid preventing gas exchange • caused by bacterial infection
Tuberculosis: • Lung infection caused by bacteria. • Highly contagious • Chest pain, prolonged cough (may cough up blood) • May cause extensive scarring in the upper lobes of the lungs.
Cystic Fibrosis: genetic disorder (recessive) • Abnormally thick, sticky mucus in lungs • Difficult for cilia to remove mucus • Frequent chest infections, coughing, shortness of breath
Lung Injury • Collapsed Lung: due to puncture of lung cavity
Asbestosis: • Asbestos fibers get trapped in lungs • Fibers irritate lung tissue creating scarring and initiating a chronic inflammatory response • No cure
Smoking and the Respiratory System • Chemicals in tobacco smoke damage structures throughout the respiratory tract. • Nicotine: • addictive stimulant that increases heart rate and blood pressure and can increase risk of heart attack • Carbon Monoxide: • poisonous gas that blocks hemoglobin from binding with oxygen • Tar: • contains at least 60 compounds known to cause cancer. • Ex: arsenic, formaldehyde
Smoke paralyzes cilia • One cigarette stops their motion for about 20 minutes • Mucus laden with particles has trouble leaving the airways resulting in “smokers cough”
Diseases Caused by Smoking • Chronic Bronchitis: • bronchial tubes become irritated and swollen • Passageways swell and clog with mucus • Heavy coughing and difficulty breathing
Emphysema: • Fragile walls of alveoli become damaged, scarred and broken • Less surface area for gas exchange • Lungs become less elastic • Get shortness of breath • Damage to lungs cannot be fixed
Lung Cancer: • Tumors crowd out functional surfaces for gas exchange and steal blood supply • By the time it is detected, it has usually spread to body • Usually caused by smoking
Adaptations for Gas Exchange in Animals • Need moist thin walled respiratory surface • for O2 and CO2 exchange • More surface area = more gas exchange
Protists and Small Multicellular Organisms • Amoeba, Paramecium, Hydra: • Most cells are in direct contact with environment • Diffusion of gases occurs across cell membrane directly
Aquatic Animals • Most often exchange gases through gills • Thin layers of tissue richly supplied with blood vessels • Provide large surface area for gas exchange • There is much less dissolved oxygen in water than in air • Air = 20%, water <1% • Must constantly move large amount of water over respiratory surface by pumping or swimming
Earthworm • Thin outer skin is the respiratory surface • Below skin are capillaries carrying blood with hemoglobin • Live in moist soil and constantly secretes mucus to keep skin moist • If exposed to air and dries out it will suffocate
Grasshopper • System of tracheal tubes for gas exchange • Branching air tubes carry air directly to cells • Muscle contractions pump air in and out of tubes • Spiracles: outside openings that lead to tracheal tubes
Review Website: • http://kidshealth.org/teen/your_body/body_basics/lungs.html • Review of Respiration: • http://www.wisc-online.com/objects/ViewObject.aspx?ID=AP15104 • Review Website with Practice Problems • http://www.biotopics.co.uk/humans/resyst.html • Interactive Anatomy Website: • http://www.anatronica.com/anatronica-flash-respiratory-system.html • Interactive Practice: • Label the parts of the Respiratory System • http://www.neok12.com/diagram/Respiratory-System-01.htm
Respiratory System: (25 minutes Coronet Film) • http://www.youtube.com/watch?v=yWnlhcqJlRk&list=PL2FC882112DF30CFB&index=24&safe=active • Bill Nye: The Respiratory System (25 minutes) • http://www.youtube.com/watch?v=q3Do0eeRReU&list=PLORF26ONn8gSytdZkl1TlWZxsDwJG-6vN&safe=active