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respiration in humans - Coggle Diagram
respiration in humans
smoking
carbon monoxide
-reduces ability of blood to transport oxygen as CO binds permanently to haemoglobin to form oxyhaemoglobin, causing less haemoglobin available to transport oxygen
-increases risk of coronary heart disease
tar
-contains carcinogens
-increases risk of lung cancer as tar can cause uncontrolled cell division
-paralyses cillia
-increases risk of chronic bronchitis and emphysema
nicotine
-increases heartbeat rate and blood pressure
-increases risk of blood clot in the arteries, leading to increased risk of coronary heart disease
-increases risk of arteries to narrow
-
chronic bronchitis
-epithelium lining of the air passages become inflamed
-gland cells secrete excess mucus
-since cilla is paralysed, the cannot sweep away dust and the mucus
-breathing becomes difficult as air passages are blocked
-persistent coughing occurs to clear the passages
emphysema
-result of persistent coughing
-partition walls of alveoli are broken down due to intense coughing, reducing surface area for gas exchnage
-lungs become elastic and inflates with air
-breathing becomes difficult and gives rise to wheezing and brathlessness
anaerobic respiratuon
-release of energy by breakdown of glucose in absence of oxygen
-only small amount of energy is released
in muscle cells
-during vigorous exercise, there will be a limit to the rate of breathing and heartbeat
-aerobic respiration cannot produce enough energy to meet the increase of energy demand. Anaerobic repiration is carried out to meet the demand
-lactic acid is formed and caused fatigue in muscles
-accumulation of lactic acid causes an oxygen debt
-to remove oxygen debt
=>continuation of fast heart rate to transport lactic acid from mucles to liver quickly and to transport oxygen from lungs to liver
=>continuation of fast breathing to take in oxygen more quickly as sufficient oxygen is needed to remove lactic acid from blood
name and function
trachea
-gland cells secrete mucus to trap dust particles and bacteria
-ciliated cells have hair-like structures called cilla to sweep the dust-trapped mucus on the trachea
alveoli
-one cell thick epithelium for faster diffusion
-dense blood capillary network to remove gases away quickly so that the conc. gradient of each gas is maintained constantly between blood and lungs
-thin layer of moisture allows gases to dissolve so that they can diffuse through the wall easily
-numerous alveoli to increase the surface area for gaseous exchange to occur quickly
gas exchange in lungs
-a conc. grad exists for each gas between the spaces in alveoli and blood, so gas exchange is carried out via diffusion
-oxygen diffuses from air in the lungs into the blood
-carbon dioxide diffuses from blood into air in the lungs
-the concentration grad is maintained by the continuous flow of blood and continuous breathing which refreshes the air in the lungs
diffusion of oxygen
-inhaled air in the alveolus contains a higher conc. of oxygen than in the blood capillaries
-oxygen dissolves in the layer of moisture on the surface of the alveolus
-it then diffuses through the wall of the alveolus and the wall of the capillary into the red blood cells
breathing
inhalation
-diaphragm muscles contract, the diaphragm flattens downwards
-external intercostal muscles contract and inner intercostal muscles relax
-ribs and sternum moves up and forward
-as the lungs expand, volume of thoracic cavity increases, causing air pressure to decrease
-atmospheric pressure is now higher than pressure in lungs, forcing air into the lungs
exhalation
-diaphragm muscles relax, the diaphragm arches upwards
-external intercostal muscles relax and internal intercostal muscles contract
-ribs and sternum move down to its original position
-as the lungs deflate, volume of thoracic cavity decreases, causing air pressure to increase
-atmospheric pressure is now lower than pressure in lungs, forcing air out of the ln=ungs
aerobic respiration
-release of energy by the breakdown of glucose in the presence of oxygen
-C6H12O6 + 6O2 → 6CO2 + 6H2O (glucose + oxygen -> carbon dioxide + water)
-energy is needed for
=>synthesis of new protoplasm for growth and repair
=>synthesis of proteins from amino acids
=>active transport of food substances
=>muscular contraction
=>transmission of nerve impulses
=>cell division