A. Human Respiratory System.

The human respiratory system consists of:i. Breathing organsii. Ribsiii. Diaphragmiv. Intercostals muscles

Nasal cavity

Nostril Oral cavity Larynx

Bronchus Right Lung

Pharynx

Trachea Carina

Left Lung

Diaphragm

Nasal cavity To warm, moisten and filter fine particles (dust)

Trachea A channel which branches into two. Each branch iscalled bronchus.

BronchusBranch which enters the lungs.

BronchioleMany channel which branches from bronchus.

Alveolus Parts which end from bronchiole. Contains a networkof blood capillaries.

Intercostal muscleSituated between the ribs. It will contract and relax to helpBreathing processesConsists of two types: internal intercostal muscle and external intercostal muscle.

The ribsProtect the lungs and internal organs like heart.

The diaphragm A piece of muscle situated at the bottom of the lungs.

The air is inhale through:

B. Breathing Mechanism

Involve 2 physical processes:Inhalation (inspiration) – air is taken into the lungsExhalation (expiration) – air is expelled from the lungs.

The intercostal muscle raises or lowers the ribsduring breathing.

The diaphragm changes the air pressure in the thoracic cavity by increasing or decreasing the volume of thoracic cavity.

Diaphragm contracted (moves down)

Diaphragm relaxed (moves up)

(a) Inhalation (b) Exhalation

Ribs

Intercostal relax(rib contract)

Intercostalcontract (rib expand)

Diaphragm contracted (moves down)

(a) Inspiration

Ribs

External intercostalscontract (rib expand)

During inhalation-Ribs rise and extend outward.-internal intercostal relax.-diaphragm contract and causes diaphragm become flat.-the volume of thoracic cavity increase (air pressure in it lower than the atmospheric pressure)-air from outside will inhale into the lungs.

Diaphragm relaxed (moves up)

(b) expiration

Ribs

Intercostal relax(rib contract)

During exhalation

-Ribs descend and fall inward.-External intercostal relax.-diaphragm relaxes and causes diaphragm curve upward.-the volume of thoracic cavity decrease (air pressure in it higher than the atmospheric pressure)-air in lungs will be pushed out

Activity 1.1Aim: To study the action of the diaphragm in the breathing mechanismMaterial: simple model to show the action of the diaphragm

Bell jar

Balloon

Rubber sheet

Holder

Glass tube

Pull down

When the handle is pulled down, the balloon expand

released

When the handle is released, the balloon contracts

Analysis:

a) Rubber sheet = Diaphragmb) Bell jar = Thoracic cavityc) Glass tube = Trachead) Y-shaped tube = Bronchuse) Balloon = lung

ae

bd

c

When the handleis pulled down

When the handle isreleased from the hand

The occurrence that takes place

IncreasesDecreasesAir moves into the balloon through the glass tube

Volume in bell jarAir pressure in

bell jarMovement of air

DecreasesIncreasesAir is forced out of the balloon through the glass tube

Red blood cell

Oxygen

Carbon dioxide

Capilary Blood flow

1. Oxygen diffuses into the blood capillaries to be carried to all the body cells.

2. Carbon dioxide diffuses from the blood capillaries into the alveolus to be eliminated.

Why are the alveolus efficient in gaseous exchange?1. Thin wall2. Moist (help gas to dissolve)3. Surrounded by network blood capillaries4. Million of alveoli to increase the large surface area

Oxygen Carbon dioxide

RedBloodcell

Liquidlayer

BloodCapillary wall

Alveolus wall

Alveolus

Red blood cell

Oxygenatedblood

Deoxygenatedblood

Oxygen is taken into the alveolus will diffuse into the blood capillaries.

In the blood, oxygen will combined with hemoglobin to formoxyhemoglobin.

Oxygenated blood – go to heart and pumped to the whole body

Deoxygenated blood – go to thelungs to be eliminated

Respiration is a food oxidation process in the body cells to Release energy, carbon dioxide and water.

Glucose + Oxygen carbon dioxide + water + energy

The energy produce is used fro daily activities like walking and maintaining body temperature.

Substances harmful to the respiratory system

a) Cigarette smoke contains:

Nicotine: causes illnesses like bronchitis,throat cancer and lung cancer

Tobacco tar: blackens the lungs and causesless efficient for gas. Causes lung cancer

Acid: corrodes lung cells. Causes coughing, asthma and Bronchitis.

Carcinogen: stimulates the growth of cancer cell.

b) Acidic gas from factories

Sulphur dioxide and nitrogen dioxide:Damage the breathing channel and lungs

Carbon monoxide:Reduce the ability of blood to transport

oxygen and causes death

c) Vehicle fumes

d) Burning forest or garbage

Haze:Damage lungs

Poisonous gas (hydrogen chloride, ammonia):Corrodes the breathing channel

e) Burning plastic material

Activity 1.2 Aim : To study the effects of smoking on the human respiratory systemApparatus : U tube, filter pump, test tube, rubber stopper, retort stand, glass tube, rubber tube, thermometer.

Thermometer

Cigarette

U-tubeWhite cotton Hydrogen

carbonate

Observation:Material ObservationThermometer The temperature

increasedWhite cotton wool Became darkish

yellowHydrogen carbonate indicator

Change from red to yellow

Analysis;1. Thermometer reading increased because cigarette smoke is hot2. White cotton became black because of tobacco tar3. Hydrogen carbonate indicator change from red to yellow shows acidic gases are presence

EFFECT ON LUNGSLung cells will be killed by heat

Smoke blackens the lungs.Smoke corrodes the lung cell

Conclusion:

Smoking rises the lung temperature.

Smoking blackens the lungs.

Smoking corrodes the lung cell

HeatTobacco tarAcidic gases

Illness affecting the respiratory system

Illnesses affecting the respiratory system include:

Lung emphysema Bronchitis

Lung cancer Asthma

Lung emphysema

Abnormal growth inthe cell which blocked the airchannel.

It is cause by chemical which is found in cigarette smoke.

Lung emphysema

This growth causes carbon dioxide be trapped in the alveoli

The alveoli in the lungs swell and Burst leaving large spaces in the Lungs

This bursting reduces the surface area of the lungs that can beused for gaseous exchange.

Lung emphysema

The symptoms are:1. Breathing difficulty2. Tiredness3. Excessive coughing

Bronchitis

Bronchitis is inflammation of the epithelium cell of the bronchus.

Bronchitis is caused by fineparticles that float in the air(air pollutant) or that are found in cigarette smoke.

BronchitisThe breathing channel will be filled with mucus.

The symptom are:a) High feverb) Breathing difficultyc) Chest painsd) Continuous heavy coughinge) Tirednessf) Weight loss

Lung cancer Cancer are usual cell growth in the lungs.

Smoking is the major cause of lung cancer.

Carcinogen , found in cigaretteIs caused cancer.

Lung cancer does not shows any symptoms at early stage.

Lung cancer

The symptoms are:a) Continuous heavy coughingb) Coughing with blood c) Weight lossd) Breathing difficultye) Feverf) Wheezingg) Chest pains

Asthma Asthma is a type of disease cause by the inflammation of the breath channel

The breathing channel suddenlybecomes narrow causing difficulty in breathing.

Asthma may be cause by dust (air pollutant), smoking orcigarette smoke.

Asthma

The symptoms are:a) Coughing, especially at night or during cold weather.

b) Breathing difficulties

c) Wheezing

d) Tightness in chest

Ways to improve air quality.1. Install tall chimney2. Install electrostatic precipitators.3. Install catalyst convectors.4. Use air cleaning system5. Burn garbage in the incinerator.6. Stop smoking.

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