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” – 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=zX7a51 620305036844477802&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 Sense of Smell • 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=Up OXecWC5Dw&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=zX0 66c555347077350076077&t=RespiratorySystem • 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=zX0 45c7b745d0a6d435f5245&t=RespiratorySystem 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=zX5 a5b076c436a5b690d0373&t=RespiratorySystem • Make a Lung/Diaphragm Model • http://www.youtube.com/watch?v=vRv2zY H5p9k&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=ac tive • Bill Nye: The Respiratory System (25 minutes) • http://www.youtube.com/watch?v=q3Do0eeRRe U&list=PLORF26ONn8gSytdZkl1TlWZxsDwJG6vN&safe=active