Respiration

• aerobic respiration- release of energy from the break down of glucose, in the presence of oxygen. CO2 and H20 released as waste products. a large amount of energy is released.
• anaerobic respiration - release of energy from the breakdown of glucose without oxygen. Lactic acid released as waste product. small amount of energy released.
• anaerobic respiration: glucose—>lactic acid+small amount of energy
• aerobic respiration: glucose+oxygen—> carbon dioxide+water+large amount of energy
• aerobic respiration: oxygen concentration in body is sufficient, heart and breathing rate are normal.
• anaerobic respiration: oxygen concentration in body is low, heart and breathing rates increase to try and get more oxygen into cells.
• anaerobic respiration: lactic acid builds up in muscles causing fatigue. muscle tissues incur oxygen debt.
• oxygen availability to cell increases, there is sufficient oxygen. lactic acid diffuses into the blood and is transported to the liver. liver will use available oxygen to break down and remove lactic acid from body
• human respiration system: nose->nasal cavity->pharynx->larynx->trachea->bronchi->bronchioles->aveoli
• nose & nasal cavity- hair & mucus on epithelial lining help filter air from large particles. harmful chemicals detected by sensory cells on epithelium.
• Trachea- supported by C-shaped cartilages.-gland cells on epithelium produce mucus.
• Trachea: cilia- hair-like structures that ciliated cells on epithelium bears, cilia sweeps mucus up trachea.
• bronchi &bronchioles: each bronchus transport air to each lung. bronchi will branch out leading to numerous small bronchioles.
• Aveoli: tiny sacs where gas exchange occurs between alveolar walls and capillaries surrounding them.
• adaptations of aveoli: epithelial wall- one cell thick — decrease diffusion distance, increase rate of diffusion of gases.
• adaptation of aveoli: inner surface of alveolus has thin film of moisture— allows oxygen to dissolve into moisture and diffuse into alveolar and capillary wall into blood.
• adaptation of aveoli: close proximity with blood capillaries-decrease diffusion distance, increase rate of diffusion
• adaptation of aveoli: numerous small aveoli in lungs— increase SA: vol ratio , increase rate of diffusion
• adaptation of aveoli: surrounded by dense network of blood capillaries- maintains steep concentration gradient to ensure efficient exchange of gases.
• effect of nicotine in tobacco smoke: addictive- causes release of “pleasure” hormone, dopamine. increase heart rate and blood pressure. decreases lumen of arteries. increases the risk of blood clots in arteries(coronary heart disease)
• effect of carbon monoxide in tobacco smoke: binds to haemoglobin- reduces O2 carrying capacity of Hb, increases risk of coronary heart disease
• effect of tar in tobacco smoke: causes uncontrolled cell division-> increases the risk of cancer. paralyses the cilia in epithelium, dust and particles trapped by mucus cannot be removed. increases the risk of chronic bronchitis and emphysema.
• chronic bronchitis: inflammation of epithelial lining eg. bronchi, excessive mucus production, cilia is paralysed and destroyed. mucus and trapped dust particles cannot be removed. air passage blocked. persistant coughing to clear air passage.
• emphysema: destruction of alveolar walls, loss of elasticity of lung tissue. airways become permanently dilated.
• lung cancer: uncontrolled cell division producing outgrowth of cells or lumps of tissues.