Respiratory system

What is Respiration?  The release of energy from food

Burning of Food oxygen food (sugar) Burning energy carbon dioxide  Energy released from food oxygen food (sugar) Burning energy carbon dioxide water

food (sugar) + oxygen burning carbon dioxide + water + energy (heat + light)  does not occur in living cells because the reaction is too fast and cells would die as they become so hot

Respiration  reactions are catalyzed by enzymes  main food substance which is oxidized in cells is glucose enzymes C6H12O6 + 6O2 6CO2 + 6H2O + energy glucose + oxygen ➨ carbon dioxide + water + energy

Respiration respiration that takes place in plants and animals uses oxygen is called aerobic respiration some bacteria do not require oxygen and this is called anaerobic respiration

Comparison of Burning and Aerobic Respiration Similarities - both involve oxidative processes - both require the use of oxygen and food and they produce the same products of carbon dioxide and water - both reactions release energy

Differences  takes place in air or oxygen  takes place in cells Burning Respiration  takes place in air or oxygen  takes place in cells  a single-step process  a series of chemical reactions  no enzymes involved  controlled by enzymes

Differences Burning Respiration  energy release is vigorous and not under control  energy release is slower and under control  energy is released in form of heat and light (a flame can result)  energy is released in form of heat and an energy-rich compound

Respiratory Structures and Organs Larynx (voicebox) Trachea (windpipe) Ribs Bronchus Bronchiole Alveoli Pleural membrane Diaphragm

Respiratory Structures and Organs trachea bronchus (bronchi) bronchioles

Respiratory Structures and Organs  Lungs – pair of cone-shaped – made of elastic tissue – divided into lobes

Respiratory Structures and Organs  Trachea (windpipe) tubular passage way for air carries air to the lungs C-shaped cartilage rings divides at end

Respiratory Structures and Organs  Bronchi pair of tubes that branch from trachea and enter lungs

Respiratory Structures and Organs  Bronchioles – tiny tubes

Respiratory Structures and Organs

Respiratory Structures and Organs  Alveoli – cup shaped structures at the end of the bronchioles, resemble bunches of grapes – are in direct contact with capillaries – gaseous exchange brings O2 into the blood from the air and releases CO2 from the blood into the air

Gaseous Exchange air moves in and out oxygenated blood to pulmonary vein deoxygenated blood from pulmonary artery cell in capillary wall CO2 plasma O2 cell in alveoli wall mucus red blood cell

Gaseous Exchange

Gaseous Exchange Earth’s atmosphere is about 78% nitrogen and about 21% oxygen What happens to the air when we inhale? 300 million alveoli in a healthy lung Haemoglobin can hold four O2 molecules GAS INHALED EXHALED O2 20.71% 14.6% CO2 .004% 4.0% H2O 1.25% 5.9%

Mechanics of Breathing  Inhaling (active process) – Air moves in  Gases move from an area of high pressure to low pressure  During inhalation – diaphragm pulls down and lungs expand  When lungs expand, it increases the volume, which decreases the pressure inside lungs  Lung pressure is lower than outside pressure, so air moves in

Mechanics of Breathing  Exhaling (passive process) – breathing out  Diaphragm and muscles relax  Volume in lungs and chest cavity decreases, so now pressure inside increases  Air moves out because pressure inside is higher than outside atmosphere

Respiratory System Disorders  Asthma – muscles of bronchioles constrict, drastically reducing ventilation  Emphysema – destruction of alveoli  Tuberculosis – highly contagious bacterial infection  Lung cancer – 90% of lung cancer victims have a history of smoking

The real reason dinosaurs became extinct

Smoking & Health  Composition of a cigarette : cigarette = carbon monoxide + nicotine + tar  Effects on health :  Tar : – carcinogenic ( producing cancer )

Smokers’ lung

Smoking & Health  Nicotine : – cause heart diseases– dependence – retards growth of foetus  Carbon Monoxide : – combines irreversibly with haemoglobin and prevents it from carrying oxygen – decrease in physical fitness – cause air pollution

Warning DO NOT SMOKE !!!!! Passive Smoking process of breathing in smoke from cigarette smokers causes nose, throat & eye irritations Warning DO NOT SMOKE !!!!!