Respiration

Definition of Respiration: Breakdown/Oxidation of food substances to release energy in living cells

A) Types of RespirationAerobic Respiration Breaking of food in the presence of oxygen Release lots of energy Carbon dioxide and water are released as waste product Equation: Glucose + Oxygen --> Carbon Dioxide + Water + EnergyAnaerobic Respiration Breaking down food in the absence of oxygen Releases less energy

a) Alcoholic Fermentation (in yeasts)Incomplete breakdown of sugar into ethanol, carbon dioxide and small amounts of energy is released.Equation: Glucose --> Ethanol + Carbon Dioxide + Energyb) Lactic Acid Fermentation (in muscles) Incomplete breakdown of sugar into lactic acid and small amounts of energy is released. Equation: Glucose --> Lactic Acid + Small amounts of energy

Muscular Exercise (during long vigorous exercise)Starting Phase Muscle cells respire aerobically Increase in breathing rate (remove carbon dioxide and take in oxygen at a faster rate) Exercising Phase After a while, the amount of oxygen supplied during maximum aerobic respiration is not enough to meet the demand of energy needed by the contracting muscle cells. Muscle cells respire anaerobically Lactic acid is formed Muscle cells incur oxygen debt Lactic acid concentration build-up/accumulate in muscle cells until it reaches a point where concentrations are high enough to cause muscle fatigue, pain and discomfort The body then needs to rest and recover. Rest and Recovery Phase Breathing rate continues to be high for a period Provide sufficient oxygen to repay oxygen debt Lactic acid is gradually removed from the muscles and transported to the liver In the liver, lactic acid is oxidized to convert some lactic acid back to glucose. Glucose transported back to muscles.

HOW DO ORGANISMS OBTAIN OXYGEN?

Through the processes:- Breathing: Physical process of inhaling and exhaling which result in air moving in and out of the lungs Gaseous Exchange: The exchange of gases between the organism and the environment Tissue respiration/Cellular Respiration: Oxidation of food substances, releasing energy, CO2 and H2O within the cells or tissues of an organism. Aerobic Respiration: Involves tissue respiration.

Inhalation: Diaphragm contracts Volume of chest cavity increases Pressure in chest cavity increases Lungs expand

Exhalation: Diaphragm relaxes Volume of chest cavity decreases Pressure in chest cavity decreases Lungs contracts

STIMULUS FOR BREATHING:High concentration of carbon dioxide in blood or air sac (NOT LACK OF OXYGEN)

Inhaled air has... More oxygen Less carbon dioxide Less water vapour Less temperature Dust particles

Exhaled air has... Less oxygen More carbon dioxide More water vapour  More temperature Little dust particles

How is oxygen absorbed into into the lungs? Oxygen from the air in the lungs dissolves in the thin film of moisture on the cells lining the alveolus. The oxygen then diffuses across the alveolus wall and through the wall of the capillary into the blood plasma. The oxygen in the plasma diffuses into the red blood and combines with haemoglobin to form oxyhaemoglobin. When the blood passes through oxygen-poor tissues, the oxyhaemoglobin releases oxygen, which will then diffuse though the blood capillaries into tissue cells.

How is carbon dioxide removed from the lungs? After aerobic respiration by tissue cells, carbon dioxide produced diffuses into blood plasma, and then diffuse into red blood cells.In red blood cells,carbon dioxide converts into hydrogen carbonate ions and diffuse out into blood plasma.In lungs,hydrogen carbonate ions diffuses back from blood plasma into red blood cells, then converted back into carbon dioxide.

Chemicals present in tobacco smoke:- Nicotine Carbon Monoxide Tar Irritants Harmful effects of smoking on:- Lungs Air Passages Heart Blood circulation

1) HARMFUL EFFECTS OF SMOKING ON LUNGS...Causing substances: Tar - contain carcinogenic(cancer causing) chemicals. Results in abnormal uncontrollable division of cells in the lung =LUNG CANCER Block off the alveoli --> reduce efficiency of gaseous exchange Causing substances: Irritants Weaken and burst the walls of alveoli Enlarges air spaces --> Decrease in surface area of alveoli --> Forming reduced number of enlarged alveoli. Reduced gaseous exchange in the lungs and oxygen absorption Lungs become over-inflated with air and lose elasticity LONG TERM EFFECT: EMPHYSEMA  

2) HARMFUL EFFECTS OF SMOKING ON AIR PASSAGES...Causing substances: Tar and Irritants Paralyses the cilia lining the air passages. Prevent cilia from recovering dust particles from trachea Long Term Effect: Chronic Bronchitis Bronchi become inflamed and narrowed Excessive mucus secreted Reduces air flow Breathing becomes difficult, hence a person wheezes and coughs

3) HARMFUL EFFECTS OF SMOKING ON HEART...Causing substances: Nicotine Causes the release of hormones --> increase in rate of heartbeat In blood clotting occurs in coronary arteries, a heart attack will occur

4) HARMFUL EFFECTS OF SMOKING ON BLOOD CIRCULATION...Causing substances: NicotineIncrease the risk of blood clot blocking blood vessels Causing substances: Carbon Monoxide Reduces efficiency of red blood cells to transport oxygen Increases the rate of deposition of fatty acids on the inner walls of arteries --> narrower lumen --> ANTHEROSCLEROSIS

Respiration

Inhalation and Exhalation

Gaseous Exchange in Lungs

Smoking