Slide 1

CHAPTER 1

RESPIRATION

1.1 ANALYSING THE HUMAN BREATHING MECHANISM

Identify The Structure Of The Human Respiratory System

The human respiratory system consists of:

Breathing organs

Ribs

Diaphragm

Intercostals muscles

Identify The Structure Of Lung

Describe The Process Of Inhalation And Exhalation And Relate The Changes Of Air Pressure In The Thoracic Cavity To Inhalation And Exhalation

The breathing mechanism involves two phases

Inhalation

Exhalation

INHALATION taking in of air or breathing in

EXHALATION letting out of air or breathing out

The air flow enter the lung:

Nostril Nasal cavityTrachea Bronchus AlveolusBronchioles

The air flow enter the lung:

The process during Inhalation

During inhalation, the internal intercostals muscles relax

Causes the ribs moves upwards and outwards

The external intercostals muscles contract

The diaphragm muscles contract and flatten

The volume of thoracic cavity increases

The air pressure inside the thoracic cavity is lower than atmospheric pressure

This causes the air from outside to be inhaled into the lungs

The process during Exhalation

During exhalation, the internal intercostals muscles contract

Causes the ribs moves downwards and inwards

The external intercostals muscles relax

The diaphragm muscles relax and curve upwards

The volume of thoracic cavity decreases

The air pressure inside the thoracic cavity is higher than atmospheric pressure

This causes the air in the lungs to be pushed out

Describe The Breathing Mechanism.

InhalationPart InvolvedExhalationContractExternal Intercostals Muscles RelaxRelaxInternal Intercostals MusclesContractUpwards And OutwardsMovement Of RibcageDownwards And InwardsContract And Flattens OutDiaphragmRelax And Curved Upwards

Comparison between inhalation and exhalation mechanism

InhalationPart InvolvedExhalationIncreasesVolume Of Thoracic Cavity DecreasesAir Pressure In The Thoracic Cavity DecreasesAir Pressure In The Thoracic Cavity Compared With Atmospheric Pressure On The OutsideAir Pressure In The Thoracic Cavity IncreasesAir Flows Into The LungsAir MovementAir Is Forced Out Of The Lung

Comparison between inhalation and exhalation mechanism

1.2 transport of oxygen in the human body

The Process Of Gaseous Exchange

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

Carbon dioxide diffuses from the blood capillaries into the alveolus to eliminated

The alveolus is efficient in gaseous exchange because:

It has a thin wall (one cell thick)

It is moist (enable gas to dissolve)

It is surrounded by a large network of blood capillaries

it has a large surface area (millions of alveoli)

Diffusion Of Oxygen Through The Alveolus Wall Into The Bloodstream

Due to high concentration of oxygen in the alveolus and the low concentration of oxygen in the blood capillaries, the diffusion of gas takes place

The oxygen on the inhaled air in the alveolus diffuses into the blood capillaries

In the blood, oxygen will combine with haemoglobin in red blood cells to form oxyhaemoglobin

Oxyhaemoglobin is transported to the heart and pump to whole body through blood vessel

The concentration of carbon dioxide in the blood capillaries is higher than that in the alveolus.

Due to this, carbon dioxide diffuses from the blood capillaries into the alveolus to be eliminated

Diffusion Of Oxygen From The Red Blood Cells Into The Body Cells

When oxyhaemoglobin reaches body tissues, it decomposes to release oxygen.

the oxygen then diffuse onto the cells

In body cells, oxygen is used for cell respiration.

Cell respiration is food oxidation process in body cells to release energy, carbon dioxide and water

Energy produced is used for daily activities like walking and maintaining body temperature

The carbon dioxide produce is carried by red blood cells to the lungs to be eliminated

1.3 IMPORTANCE OF HEALTHY RESPIRATORY SYSTEM

CHEMICAL SUBSTANCEHARMFUL EFFECTS ON THE RESPIRATORY SYSTEM(a) Cigarette smoke- Nicotine Causes illnesses like bronchitis, throat cancer and lung cancerCauses addiction- Tobacco tarBlackens the lungs and causes them to be less efficient for gaseous exchangeDamages alveolus cells and lung cellsCauses lung cancer- AcidCorrodes lung cells and cells that line the breathing channelCauses illnesses like coughing, asthma and bronchitis- CarcinogenStimulates the growth of cancer cells, causing lung cancer and throat cancer

CHEMICAL SUBSTANCEHARMFUL EFFECTS ON THE RESPIRATORY SYSTEM(b) Acidic gas from factories- Sulphur dioxide and nitrogen dioxideDamages the breathing channel and lungsCauses breathing difficulties(c) Vehicle fumes- Carbon monoxideReduces the ability of blood to transport oxygen and causes death in severe cases(d) Burning forest or garbage- HazeDamage the lungsCauses breathing difficulties(e) Burning plastic material- Poisonous gases like hydrogen chloride, ammonia, and hydrogen cyanideCorrodes the breathing channel

The Illnesses Of The Respiratory System

LUNG EMPHYSEMA

Happens as a result of abnormal growth in the cells that lines the tiny channels in the lungs causing these channels to become blocked

the symptoms are:

Breathing difficulty

Tiredness

Excessive coughing

BRONCHITIS

Is inflammation of the epithelium of the bronchus

Is caused by fine particles that float in the air or that are found in cigarette smoke

The symptoms are:

High fever

Breathing difficulty

Chest pain

Continuous heavy coughing

Patients phlegm changes colour from white to yellow or green

LUNG CANCER

Is caused by unusual cell growths in the lungs

Smoking is the major cause of lung cancer

Carcinogens that are found in cigarettes can cause lung cancer

The symptoms are:

Continuous heavy coughing

Coughing with blood

Weight loss

Loss of appetite

Breathing difficulty

fever

ASTHMA

Caused by the inflammation of the breathing channel

The breathing channel of the patient suddenly becomes narrow causing difficulty in breathing

Asthma may be caused by dust, smoking or cigarette smoke

The symptoms are:

Coughing especially at night or during cold weather

Breathing difficulty

Wheezing and tightness in the chest

Ways To Improve Air Quality

Install tall chimneys in factories that emit dangerous smoke and gas so that such dangerous substances are kept at a higher level in the atmosphere

Install electrostatic precipitators in factory chimneys to remove pollutants before smoke is released into the atmosphere

Install catalyst converters on vehicle exhaust pipes to reduce the release of dangerous gases like carbon monoxide

Use air cleaning system to dissolve toxic gases like sulphur dioxide and nitrogen dioxide in water before it is released into atmosphere

Burn garbage in special place like the incinerator

Stop smoking to prevent the release of cigarette smoke into environment