respiration in humans

• label the respiratory system: 1) pharynx 2) larynx 3) trachea 4) bronchi 5) lungs 7) alveoli 8) bronchioles

  
• structure-function of nose: fringe of hair lining nostrils and lined with mucous membrane— traps dust, foreign particles and bacteria in air, moistens and warms air, small sensory cells detect harmful chemicals
• structure-function of trachea: rings of C-shaped cartilage— supports and keeps lumen of trachea open. epithelium of membrane made up of mucus secreting gland cells & cilia bearing cells— gland cells: mucus traps dust & bacteria. ciliated cells: sweeping of dust-trapped mucus up trachea by cilia
• structure function of bronchi/bronchioles: rings of C-shapes cartilage— supports & keeps lumen of bronchi & bronchioles open, allows air to flow into lungs
• SF of alveoli: numerous alveoli in lungs— increase SA:vol for faster exchange of gases. walls of alveolus is one cell thick— short diffusion distance for gases, faster rate of diffusion. surface of alveolus covered by thin film of moisture— allows o2 to dissolve. walls of alveoli are richly supplied w blood capillaries— flow of blood maintains concentration gradient of gases
• describe the process of inhalation: Diaphragm muscle contracts, diaphragm flattens down. External intercostal muscles contract, internal intercostal muscle relax. Rib cage is raised upwards and outwards. Sternum moves forward. Thoracic cavity volume increases. Lungs expand, increasing in volume & air, pressure within decreases. Atmospheric p. > lungs p. Air is forced into lungs
• describe the process of exhalation: Diaphragm muscles relax, diaphragm arches upwards. External intercostal muscle relax, internal intercostal muscle contract. Rib cage moves downward & inward. Sternum moves down. Thoracic cavity volume decreases. Lungs compresses, decreasing in volume & air pressure within increases. Lungs p. > atmospheric p. Air is forced out of the lungs
• effects of nicotine: addictive— addiction. causes release of adrenaline— increases heartbeat rate & blood pressure. makes blood clot easily— increase risk of blood clots in arteries leading to increased risk of coronary heart disease.
• effects of carbon monoxide: combines more readily & irreversibly with haemoglobin to form carboxyhemoglobin— reduces volume of O2 transported by red blood cell in blood. increases fatty deposits on inner surface of arterial wall— narrowing lumen of arteries causes increases blood pressure & increases risk of coronary heart disease
• effects of tar: causes uncontrolled cell division— increases cancer risk in lungs. paralyses cilia lining in air passages— dust particles in air cannot be removed increasing risk of chronic bronchitis & emphysema
• define aerobic respiration: oxidation on food substances in the presence of O2 with the release of a large amount of energy. CO2 and water are formed as waste products
• what is the chemical & word eqn of aerobic respiratio: word— Glucose + oxygen —> water + CO2 (with a lot of energy released) chemical— C6H12O2 + 6O2 —> 6H2O + 6CO2 (with a lot of energy released)
• define anaerobic respiration & the word eqn: chemical breakdown of food substances in the absence of O2. releases less energy. Glucose —> lactic acid (with little energy released)
• what happens when anaerobic respiration occurs: increase in rate of muscular contraction increases demand of energy and hence respiration rate needs to increase. demand for O2 supply in muscle tissues increases for increased rate of respiration. maximum O2 uptake (by inhalation) is less than O2 demand causing muscles to respire anaerobically to release additional energy, buildup of lactic acid & O2 debt in muscle causing muscle fatigue. O2 debt: the amount of O2 required to oxidise lactic acid produced by anaerobic respiration of muscles
• what happens after exercise: the recovery period (breathing & heart rate remains high) is needed to provide additional O2 to repay O2 debt of muscles. some lactic acid transported to liver oxidised to release energy. energy converts remaining lactic acid to glucose
• effects of chronic bronchitis: epithelium lining of air passages becomes inflamed secreting excess mucus. cilia lining on epithelium is paralysed resulting dust and mucus not removed. air passages becomes block, persistent coughing to clear passages to breathe, increasing risk of lung infections
• effect of emphysema: partition walls between alveoli walls break down. decreases SA:volume for gaseous exchange. lungs loses elasticity & inflated w air. difficulty in breathing