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