respiration form 3
TRANSCRIPT
RESPIRATION
• Respiration = chemical process whereby energy is released from glucose or other simple substances
• Oxygen taken into body when we breathe
• Glucose from food we eat
• Exchange of gases known as breathing
Human breathing mechanism
Glucose + oxygen energy + carbon dioxide + water
Structure of human respiratory system
Structure of lung
• Lungs are made up of :– bronchioles – Alveoli (singular : alveolus)– Blood capilaries
• Lungs are protected by rib cage
• Thoracic cavity = houses of the lung
Flow of air from the atmosphere to the lungs
Alveolus
Nostril
Bronchiole
Bronchus
Trachea
Nasal cavity
• Gaseous exchange takes place in the lungs by diffusion
• An alveolus has adaptations to allow it to exchange gases effectively. It has:– Large surface area– Thin and elastic walls– Surround by a network of blood capillaries– Moist surface
• Process of taking air into lung = inhalation
• Air enter lung = inhaled air
• Process of expelling air from lung = exhalation
• Air expelled from lung = exhaled air
The breathing mechanism
Inhalation
Exhalation
Inhalation Exhalation
External intercostal muscles contract
External intercostal muscles relax
Rib cage moves upwards and outwards
Rib cage moves moves downwards and inwards
The diaphragm contracts and flatens
The diaphragm relaxes and curves upwards
The volume of the thoracic cavity increase
The volume of the thoracic cavity decrease
The air pressure in the thoracic cavity decreases
The air pressure in the thoracic cavity inreases
Air enters the lungs Air is forced out of the lungs
The breathing mechanism
Balloon expand Balloon contract
Bell jar
Glass tube
Rubber sheet
• Bell jar = rib cage
• Balloons = lungs
• Rubber sheet = diaphragm
• When rubber sheet is pulled downwards, air pressure inside bell jar is lowered. Balloons expand
• When rubber sheet is pulled upwards, air pressure inside bell jar increased. Balloons contract
Transport of oxygen in the human body
• Involve the following process– Diffusion of oxygen from the alveoli into blood
capillaries– Transport of oxygen by red blood cells– Diffusion of oxygen from the blood capillaries into
cells
• Oxygen – diffuse from alveoli to the blood capillary
• Carbon dioxide - diffuse from blood capillary to the alveoli
• Oxyigen are not soluble in red blood cell
• red blood cell contain pigment - haemoglobin red in coloured
• Oxygen will combine with haemoglobin• Haemoglobin + O2 -> O2Hb(oxyhaemoglobin)
Improtance of healthy respiratory system
Effect of smoke to respiratory system
• Cigarette smoke contains irritants chemical :• A carcinogen - an agent directly involved in
causing cancer. • Nicotine – cause addicted• Carbon monoxide – cause death • Sulfur oxide – acidic = damages lung tissues• Tar – blackens the lungs and causes them to be
less efficient for gaseous exchange
Bahan – bahan lain yang merbahaya
• Hasil daripada sisa industri seperti:– Debu simen– Debu arang– Debu asbestos
• Pencemaran daripada asap kenderaan\– Karbon monoksida– Hidrokarbon- karsinogenik– Nitrogen oksida – hujan asid
Masalah pernafasan
• Bronkitis - sejenis keradangan atau kerengsaan pada saluran pernafasan (tiub bronkiul) di dalam paru-paru.
• Asma - sejenis penyakit paru-paru yang terjadi akibat radang dan penguncupan saluran pernafasan.
• Kanser paru - paru