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RESPIRATION

OxygenCarbon dioxide

Carbon dioxide

Carbon dioxide

Carbon dioxide

Oxygen

Oxygen

Oxygen

Oxygen

Oxygen

Lungs

Lungs

LungsLungs

Lungs

Ribs

Ribs

Ribs

Trachea

Trachea

Trachea

Alveolus

Alveolus

Alveolus

Alveolus

Form 3 Science

Chapter One

RESPIRATION

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1. All living organisms need to take in oxygen in order to carry out cellularrespiration (still remember ? Glucose + oxygen carbon dioxide + water

+ energy).2. Respiration is the taking in of oxygen by our body from the external

environment.

3. Inhalation breathing in, exhalation breathingout.

4. Small organism, amoeba, can get the gas itneeds through simple diffusion because itsbody surface is big (compared to its body size).

5. Human has big body size and so its surfacearea is small, so he needs a respiratory systemso that the gas he breath in is enough.

Why a respiratory system is needed ?

Comparisonbetween a human

and an amoeba.

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Structure of air passage

Air passage into the lungs

1. Nostril nasal cavity pharynx trachea bronchus bronchiolesalveolus

2. Breathing through the nosea. Trap foreign particlesb. Moist and warm the airc. Detect dangerous gas3. Trachea has a cartilage ring to keep the air passage open4. Trachea opens into two bronchus.5. Bronchus open into bronchioles, eventually into air sacs, called alveolus.

6. The inner lining of trachea has a layer of mucus to trap particles, secreted bygoblet cells.

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Alveolus

1. At the end of the bronchioles are

small air sacs called alveoli.2. At the alveoli, gases exchange

takes place.3. Adaptation of alveolus for gases

exchange:

a. Moist surface

easier gas diffusionb. Thin alveolus wall, shorter distance

of diffusionc. Large number of capillaries

better transportationd. Large number of alveolus larger

surface for diffusion

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Structure of the supporting tissues

1. The ribs2. Intercostals muscle

3. Diaphragm4. There are 10 pairs of ribs attaching

backbone and the sternum5. Intercostals muscle attaches to the ribs.6. When the intercostals muscle contract,

the ribs move upwards and outwards,and vice-versa.

7. Diaphragm is situated at the bottom ofthe rib cage. At rest, it curves upwardsand flatten when contracts.

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Inhalation

1. Intercostals muscle contract2. The ribs move upwards and outwards.3. The diaphragm muscle contract, and it flattens.4. The thoracic cavity increases.5. The air pressure in the lungs lowers.6. Atmospheric air pressure forces the air into the lungs.

1. Intercostals muscle relax2. The ribs move downwards and inwards.3. The diaphragm muscle relax, and it curves upwards.4. The thoracic cavity decreases.5. The air pressure in the lungs rises.6. Air pressure in the lungs forces the air out into the atmosphere.

Exhalation

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The transport of oxygen in the human body

Alveolus

Blood

Cell

Hb + O2 HbO2 HbO2 Hb + O2

Hb + CO2 HbCO2

CO2

O2

HbCO2 Hb + CO2

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In the alveolus O2moisture alveolus wall blood in the capillary

In the blood Oxyhaemoglobin is carried to the cells

At the cells

O2

is supplied to the cells. Respiration is carried out. CO2

is produced.

CO2 diffuses into the blood.

In the blood CO2 combines with haemoglobin to form carbaminohaemoglobin.Carbaminohaemoglobin is carried to the lungs.

In the alveolus Carbaminohaemoglobin breaks into Hb and CO2.CO2 diffuses into the alveolus.

Oxyhaemoglobin breaks into Hb and O2.

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Smoking, smoke from factories, open burning, etc releases harmful substances.

The importance of healthy respiratory system

Respiratory system is important and must be taken care of properly.Some harmful substances that may harm RS.

1. Tar alveolus wall less elastic, block air passages.- prevent harmful substances from removal.

2. Carbon monoxide binds with Hb, and Hb cannot bind O2.

3. Harmful substances

cause cancer.

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Respiratory diseases

1. Bronchitis2. Emphysema3. Smoking mother.

How to improve air quality

1. Stop smoking2. Control the flow and the number of traffic.3. Use unleaded petrol4. Encourage car pooling

5. Use catalytic converters to reduce the amount of harmful substancesfrom the vehicles

6. Enforce laws to curb pollutants from factories and vehicles7. Stop open burning8. Planting of more trees.