The Terms To Know
1) Alveolar ducts:
The bronchioles progressively lose the cartilages as they become narrower and end as fine tubules called alveolar ducts.
2) Alveolus:
Alveolus (single: alveoli) are the tiny air sacs structures present next to the alveolar duct of the lungs which allows rapid gaseous exchange.
3) Asthma:
Asthma is a form of allergy, in which there is inflammation of the bronchi, more mucus production and narrowing of the airways.
4) Breathing:
Breathing is the process through which animals take in air in their bodies to get oxygen and exhale air to get rid of carbon dioxide.
5) Bronchioles:
Bronchioles are the fine tubules formed by the divisions of the bronchi.
6) Bronchitis:
Bronchitis is the inflammation of the bronchi or bronchioles which results in excessive secretions of mucus into the tubes, leading to the swelling of tubular walls and narrowing of tubes
7) Bronchus:
The bronchus is the part of the air passageway formed by the division of the trachea.
8) Diaphragm:
A diaphragm is a dome-shaped thick muscular structure that forms the floor of the chest cavity, present just below the lungs.
9) Emphysema:
Emphysema is a respiratory disease in which the destruction of the cell walls of alveoli results in larger sacs but with less surface area for gaseous exchange.
10) Exhalation:
The phase of breathing in which the air is expelled out from the lungs.
11) Gaseous Exchange:
Taking in oxygen and giving out carbon dioxide is termed as gaseous exchange.
12) Inhalation:
Inhalation is the phase of breathing in which air is drawn into the lungs.
13) Larynx:
The larynx is a box-like structure, made of cartilage present between pharynx and trachea.
14) Lenticels:
Lenticels are the pores in bark of woody stems and roots which allows the air passage and removal of waste material in plants.
15) Nasal cavity:
The nasal cavity is a hollow space in the nose, opened to the outside through nostrils, divided into two portions by a wall.
16) Nostril:
The openings of the nasal cavity in the nose are called nostrils.
17) Pneumonia:
Pneumonia is an infection of the lungs caused by a bacteria, virus or fungi as a result the infected part of the lung becomes filled with pus and fluid.
18) Trachea:
The trachea is a large 12cm tube reinforced by rings of cartilage, extending from the larynx to the bronchi and conveying air to and from the lungs also called windpipe.
19) Vocal cords:
Vocal cords are two pairs of fibrous bands (tissues) in the larynx that vibrate when the air passes through them and produce sound.
Short Questions
Q.1) Differentiate between breathing and cellular respiration.
Answer:
Q.2) Trace the path of air from the nasal cavity to the alveoli.
Answer:
Air passageway and the lungs
The passage of air from nostril to the lungs takes place in the following sequence:
Nostril→ Nasal cavity→ pharynx→ Larynx→ Epiglottis→ Glottis→ Trachea→ Bronchi→ Bronchioles→ Alveolar duct→ Alveoli.
Q.3) How will you differentiate between a stoma and a lenticel?
Answer:
Q.1) How do the different parts of the plant body exchange gases with the environment?
Answer:
Gaseous exchange in plants:
Plants have no organs or systems for the exchange of gases with the environment.Every cell of the plant body exchanges gases with the environment by its own.
1- Gaseous exchange in stomata:
The leaves and the young stems have stomata in their epidermis. The gaseous exchange occurs through these stomata. The inner cells of leaves(mesophyll) and stems also have air spaces among them, which help in exchange of gases.
Gaseous exchange in a leaf:
Leaf cells have two situations.
Gaseous exchange in a leaf during daytime:
During daytime, When the mesophyll cells of leaves are carrying out photosynthesis and respiration side by side, the oxygen produced in photosynthesis is utilized in cellular respiration. Similarly, the carbon dioxide produced during cellular respiration is utilized in photosynthesis.
Gaseous exchange in a leaf during night:
However, during the night when no photosynthesis occurs, the leaf cells get oxygen from the environment and release carbon dioxide through stomata.
2- Gaseous exchange in lenticels:
In woody stems and mature roots, the entire surface is covered by bark which is impervious to gases or water. However, there are certain pores in the layer of bark which are called lenticels. The lenticels are slightly more raised than the general surface of the stem.
Gaseous exchange in a leaf
3- Gaseous exchange in roots:
In young roots,gases exchange through the general surface by simple diffusion. The gases are found in the soil surrounding the roots.
4- Gaseous exchange in aquatic plants:
The aquatic plants get the oxygen dissolved in water and release carbon dioxide in the water.
Q.2) Write down the steps of inhalation and exhalation.
Answer:
The mechanism of breathing:
"Breathing is the mechanical or physical process of exchange of gases through which animals take air in their body to get oxygen and expel carbon dioxide."
Phases of breathing:
There are two main phases of breathing.
Steps of Inspiration or Inhalation:
"Inhalation or inspiration is a process where humans intake oxygen through the nostrils which pass through the air passageway to the lungs."
During inspiration, the rib muscles contract and the ribs are raised.
At the same time, the domed-shaped diaphragm contracts and is lowered.
These movements increase the area of the thoracic cavity, which reduces the pressure on the lungs.
As a result, the lungs expand and the air pressure within them also decreases.
The air from outside rushes into the lungs to equalize the pressure on both sides.
Q.3) State the signs and symptoms, causes and treatments of bronchitis, emphysema and pneumonia.
Answer:
1-Bronchitis:
“Bronchitis is the inflammation of the bronchi or bronchioles which results in excessive secretions of mucus into the tubes, leading to the swelling of tubular walls and narrowing of tubes.”
Sign and Symptoms:
Symptoms of bronchitis include a cough, mild wheezing, fever, chills, and shortness of breath (when doing a hard job).
Causes/Pathogenic agent:
It is caused by viruses, bacteria or exposure to chemical irritants (e.g. tobacco smoke.
Treatment and drug therapy:
In most cases, bronchitis requires self-care treatments such as getting more rest, taking pain killers, drinking more fluids, breathing in warm, moist air.
Medications:
The treatment requires antibiotic and cough syrups.
Types of Bronchitis:
There are two major types of bronchitis.
Acute Bronchitis:
Acute bronchitis usually lasts about two weeks and patients recover with no permanent damage to the bronchi or bronchioles.
Chronic Bronchitis:
In chronic bronchitis, the bronchi develop chronic inflammation. It usually lasts for three months to two years.
The majority of people diagnosed with chronic bronchitis are 45 years of age or older.
2- Emphysema:
“Emphysema is the destruction of the walls of the alveoli.”
Causes:
The destruction of the cell walls of alveoli results in larger sacs but with less surface area for gaseous exchange. As lung tissue breaks down, the lungs do not come back to their original shape after exhalation. So air cannot be pushed out and it is trapped in the lungs.
Signs and Symptoms:
The symptoms of emphysema include shortness of breath, fatigue, recurrent respiratory infections, and weight loss. By the time the symptoms of emphysema appear the patient has usually lost 50-70% of his /her lung tissue. The level of oxygen in the blood may get so low that it causes serious complications.
Treatment and drugs:
Bronchodilators may help in shortness of breath.
Corticosteroids drugs inhaled as aerosol sprays may help relieve shortness of breath.
Antibiotics are also used for the treatment of emphysema
Q.4) How does tobacco smoke damage the respiratory system?
Answer:
Bad effects of Smoking on respiratory system:
Chemical Agents present in cigarettes:
Smoking is harmful due to the chemicals in cigarettes and smoke. Tobacco smoke contains over 4,000 different chemicals, Out of which at least 50 are carcinogens and many are poisonous. Nicotine and carbon monoxide are two main carcinogenic agents present in cigarettes.
Many people think that lung cancer is only smoke related disease and it is the number one cause of death among smokers. But it is not right. Cigarette smoke affects the body from head to toe. Smokers have a much higher risk of developing the number of life threatening diseases.
Carcinogenic effects of smoking:
Lung Cancer:
"Lung cancer is a disease of uncontrolled cell divisions in the tissues of the lungs." Passive smoking (the inhalation of smoke from another’s smoking) is also a cause of lung cancer. Lung cancer is the most common form of cancer caused by smoking. More than 80% of cases of lung cancer are due to smoking.
Effects on lungs:
Smokers are at great risk of developing infections, particularly in the lungs. For example, smoking increases the risk of tuberculosis by two to four times and of pneumonia four times. Many chemicals present in tobacco smoke cause damage to the air passageway which leads to emphysema.
Activities
Q.1) Investigate the effect of light on the net gaseous exchange from leaf, by using bicarbonate as the indicator.
Answer:
Plants respire all the time, but photosynthesis occurs only during the day. This means that the net gas exchange from a leaf depends on the light intensity. To measure the light intensity effect on the net gaseous exchange, a bicarbonate indicator is used.
Bicarbonate/Hydrogen carbonate (HCO3) indicator is used to show carbon dioxide concentration in solution. A leaf is placed in a stoppered boiling tube containing some hydrogen carbonate indicator solution. The effect of light intensity can then be investigated.
Bicarbonate indicator:
Normal CO2 = Orange
Increased CO2 = Yellow
Decreased CO2 = Purple
Materials required:
Test tubes, bicarbonate solution, leaves, aluminum foil.
Procedure:
Take 4 test tubes and add the same volume of hydro-carbonate indicator to each of them.
Then take 3 similar size leaves, roll them up and trap the leaf stem with the bung so they're sitting above the indicator
Wrap aluminum foil around the 1st test tube, baking paper on the second and leave the 3rd one open.
Place them in bright light and leave them for an hour. Then check the colour of the indicator
The 4th tube is the control. If the indicator changes in the control tube there is something wrong with the experiment.
Observations:
Conclusions:
Q.2) Investigate the breathing rate at rest and after exercise.
Answer:
"Breathing rate is the number of breaths per minute".
A breath is one inhalation (taking in air) and one exhalation (giving out air). Breathing takes place by the movement of lungs, ribs, and diaphragm.
During inhalation, the diaphragm contracts and the ribs expand which makes the chest cavity larger. Lungs expand and the air from the atmosphere rushes into the lungs.
During exhalation, diaphragm and ribs return to their original positions decreasing the volume of the chest cavity. Lungs contract and air moves out of the lungs. Breathing rate depends on several factors i.e. altitude, lung capacity, health and level of activity (rest or exercise) Here we will study how a change in the level of activity will bring a change in the breathing rate.
Materials:
Stop watch
Procedure:
Ask the observer to count and record the breathing rate of other students of the group in the resting position.
Do some light exercise (e.g. walking) for five minutes.
Ask the observer to count the breathing rate and again note the observations.
After 15 minutes do some strenuous exercise (e.g. running) for five minutes.
Ask the observer to count the breathing rate of the group again.
Observations:
Conclusions:
Compare all these observations and interpret the results.
Q.3) Find out how much air a person can take into his lungs.
Answer:
Practical activity:
Respiration allows the exchange of oxygen and carbon dioxide which occur in lungs having an extensive network of pulmonary capillaries and alveoli. In lungs, oxygen diffuses from the alveoli into the capillaries and carbon dioxide diffuses from the capillaries into the alveoli. After the exchange of gases, air is breathed out by expiration.
The maximum amount of air that the lungs can hold during a deep breath is called total lung capacity. The average lung capacity of an adult human is about 5 liters. During normal breathing, the volume of air that moves in and out of the lungs in each breath is called tidal volume. The volume varies for different individuals. Average tidal volume of a young adult male is 500ml and the adult female is 387ml.
Materials required:
Beaker, retort stand, delivery tube, rubber tube, graduated tube.
Procedure:
Take a beaker and fill it with water.
Take a 500ml graduated tube/cylinder and fill it with water.
Invert the graduated tube/cylinder into a water-filled beaker or trough as shown in the figure.
Blow air once through a delivery tube/rubber tube into the graduated tube/cylinder. The air displaces the water downward in the graduated tube.
Record how much water has dropped down in the graduated tube.
Measuring of inhaled and exhaled air
Observation:
Conclusion:
Q.4) Demonstrate through experiment that carbon dioxide is exhaled during respiration.
Answer:
Practical activity:
During breathing air is drawn into (inhalation) and out (exhalation) of the lungs and gas exchange between the air and blood takes place. In lungs, the oxygen is taken from the inhaled air into the blood and carbon dioxide is given out of the blood into air. Carbon dioxide turns lime water milky.
Materials required:
Conical flask, delivery tube, lime water corks.
Procedure:
Take two conical flasks and mark them ‘A’ and ‘B’.
Fill ¼ volume of each flask with lime water
Close flask ‘B’ with a cork.
Pass a glass tube through another cork and fix it on the mouth of flask ‘A’.
Take a deep breath and blow air in the flask ‘A’ through the glass tube.
Experimental setup:
Observations:
Observe the colour changes in both flask of lime water
Conclusion:
Science, Technology And Society
Q.1) Evaluate the effects of tilling on roots for better exchange of gases with the soil air.
Answer:
Tilling/Tillage:
"Tilling/Tillage is the agricultural preparation of soil by mechanical ways such as digging, stirring and overturning the soil layer."
Effects of Tilling on roots for better exchange of gases:
Tillage/Tilling improves the flow of air in the soil. This process enhances the release of soil nutrients which are used by new seeds and prepares a favourable seedbed which facilitates the root growth in the soil and improves the flow of water and air within the soil. It also increases water infiltration and soil porosity which increases the diffusion of gases into and out of the soil from higher to lower concentration. so tilling improves the gaseous exchange which increases the root growth in soil.
Q.2) Outline the concept of Artificial Ventilator for artificial breathing in patients.
Answer:
Artificial Ventilation:
Artificial ventilation is any means of producing gas exchange mechanically or manually between the lungs and the surrounding air, which is not performed entirely by the person's own respiratory system.
Concept of Artificial Ventilator:
The process of supporting breathing by application of mechanical or manual means, when normal breathing is inefficient or not present. Artificial ventilators provide air for a person who is not breathing or is not making sufficient respiratory effort on his/her own. It is used by patients whose heartbeat slows down to provide air to the body to achieve internal respiration.
Artificial Ventilator
Q.3) Interpret the dangers of breathing in exhausts of fossil fuels (Petrol and others).
Answer:
Exhaust gases:
Exhaust gases are the gases which are emitted as a result of the burning of fossil fuels such as petrol, diesel, natural gas or coal.
Dangers of breathing in exhausts of fossil fuels:
All vehicles, especially diesel engines, emit very fine pollutants such as carbon dioxide (CO2) , carbon mono-oxide(CO), nitrogen dioxide (NO2) and hydrocarbons.
The exhausts of fossil fuels are poisonous to human health. Exhausts badly affect the human breathing system.
The exhaust from an internal combustion engine that burns fossil fuel (hydrocarbon) will always contain some carbon monoxide. Carbon monoxide is colorless, odorless and tasteless and it attaches to your blood's hemoglobin and affects the oxygen carrying capacity of blood.
The breathing in an exhaust of fossil fuels causes a number of diseases which include cardiovascular disease, asthma, chronic obstructive pulmonary disease, and lung cancer.
Vehicles emit numerous carcinogenic chemicals e.g. carbon mono-oxide, benzene and formaldehyde which contribute to as many as half of all cancers attributed to air pollution.
Q.4) Rationalize the importance of cross ventilation in homes.
Answer:
Cross Ventilation:
"Cross ventilation is the circulation or flow of air through openings such as doors, windows or grilles that are on opposite sides of a room. "
Importance of cross ventilation in homes:
Cross ventilation in homes allows the fresh air to enter the house so it's healthy for people living in the house because it increases oxygenation and also removes damp air from the house.
Cross-ventilation under the home reduces the build-up of damp air beneath a floor.
The air inside a building needs to be replenished regularly. Static air can hold moisture and cause mold.
It can also smell bad, and make a building uncomfortable to be in for an occupant.
Without a supply of new air, sources of irritation and allergy in the air, such as dust or hair, can also adversely affect health.
Poor ventilation or damp places can cause a number of diseases such as asthma, chronic bronchitis, and tuberculosis because bacteria can easily grow in poorly ventilated places.
Q.5) Assess the adverse effects associated with smoking on health.
Answer:
Bad effects of Smoking:
Chemical Agents present in cigarettes:
Smoking is harmful due to the chemicals in cigarettes and smoke. Tobacco smoke contains over 4,000 different chemicals, Out of which at least 50 are carcinogens and many are poisonous. Nicotine and carbon monoxide are two main carcinogenic agents present in cigarettes.
Many people think that lung cancer is only smoke related disease and it is the number one cause of death among smokers. But it is not right. Cigarette smoke affects the body from head to toe. Smokers have a much higher risk of developing the number of life threatening diseases.
Carcinogenic effects of smoking:
Lung Cancer:
Smoking is the main cause of lung cancer. Lung cancer is a disease of uncontrolled cell divisions in the tissues of the lungs. Passive smoking (the inhalation of smoke from another’s smoking) is also a cause of lung cancer. Passive smokers can increase their heart disease risk by 25-30% and lung cancer risk by 20-30%.
Cancer risk to other organs of body:
Smoking may also lead to cancers in the kidney, oral cavity, larynx, breast, bladder, and pancreas.
Effects on lungs:
Smokers are at great risk of developing infections, particularly in the lungs. For example, smoking increases the risk of tuberculosis by two to four times and of pneumonia four times.
Effects on the circulatory system:
Smoking also has effects on the circulatory system. The carbon monoxide present in smoke lessens the oxygen carrying capacity of hemoglobin. Many other chemicals in smoke increase the production of blood platelets which make the blood viscous leading to arteriosclerosis.
Tooth staining:
Smoking is also responsible for weakening and staining the teeth. Tooth loss is 2-3 times higher in smokers than non-smokers.
Q.6) Point out bad social aspects of smoking.
Answer:
Bad social aspects of smoking:
Smoking also affects the social life of a person. Smokers may face social un-acceptance because other people may not want to be exposed to cigarette smoke. Passive smoking is more dangerous than active smoking because smoke from the burning end of a cigarette is more dangerous than the smoke from the filter end. Passive smoking is also a cause of lung cancer.
1- Increase tooth decay:
Smokers may lose teeth too early because of tooth decay. Tooth loss is 2-3 times higher in smokers than non-smokers.
2- Yellow staining of teeth:
It can be expensive to whiten teeth stained by smoking by scaling. Having yellow teeth makes a person look older and is unattractive to others.
3- Smoker’s cough:
Smoker’s cough may make other people avoid the smoker. Smokers' coughs are also called chronic bronchitis. Smoking also increases the asthma rate in smokers.
4- Cause bad breath:
People may not want to get very close to a smoker because of the bad breath.
5- Make clothes smell bad:
Many people don't like the smell of smokers’ clothes and are even allergic to the smoke and will keep their distance.
6- Decrease athletic ability:
Smokers generally don’t perform as well as athletes who don’t smoke.
7- Smoking is expensive:
Smokers have less money for other activities because they spend more money on cigarettes.
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