Organs Responsible for Gaseous Exchange in Living Organisms
Identify organs responsible for gaseous exchange in living organisms
Organs responsible for gaseous exchange in living organisms include the following:
ORGANISM
RESPIRATORY SURFACE
Amoeba
Cell membrane
Insects
Tracheal system
Spider
Book lung
Fish
Gills
Plants
Leaves, stems, roots
Amphibians
Skin, gills and lungs
Mammals
Lungs
Birds
Lungs
reptiles
Lungs
Features of Respiratory Surface
They are thin to reduce diffusion distance
They are moist to dissolve gaseous so that they dissolve and diffuse in solution form
They are highly braced, folded or flattened in order to increase the surface area for gaseous exchange
They are close to efficient transport and exchange easily by the cells
They are well ventilated so that gaseous passes easily
The Concept of Gaseous Exchange
Explain the concept of gaseous exchange
Gaseous exchange refers to the movement of oxygen and carbon dioxide across the respiratory surface. Is the process through which respiratory gaseous are passed through the respiratory surface. Respiratory surface are specialized organs for gaseous exchange. Gaseous exchange takes place through a process of diffusion.
Gaseous Exchange in Mammals
Parts of the Respiratory System
Identify parts of the respiratory system
The gaseous exchange in mammals takes place in the lungs.
The Features of Different Parts of the Respiratory System and their Adaptive Features
Describe the features of different parts of the respiratory system and their adaptive features
The Features of Different Parts of the Respiratory System include the following:
Nose and nasal cavity:It has mucus and hair which trap dust and microorganisms
Glottis: It is situated in the epiglottis which closes the trachea during swallowing to prevent food from entering the respiratory system
Trachea, Bronchus, and Bronchioles: They have blood vessel which have ring cartilage and mucus which warm hair and prevent collapse of respiratory track also they trap and fitter dust and micro organisms
Lungs:They are sponge with air space (alveoli) which is the main organ of mammalian gaseous exchange
Ribs:They are made up of hard bone tissues which protect the lungs from injury.
Intercostal muscles:They more antagonistically to allow expansion and relaxation of the thoraic cavity
Diaphragm: is the muscular sheet of tissue which separate thorax from abdomen
Alveoli: they are numerous in number; they are moist and thin membranes
Functions of alveolus
Provide surface area for gaseous exchange
Reduce distance for diffusion of gaseous
Enable gaseous to dissolve into solution before diffusing
Transport oxygen from the alveoli to the tissues and carbon dioxide to the alveoli
Maintain the shape and avoid collapsing
The Mechanism of Gaseous Exchange in Mammals
Describe the mechanism of gaseous exchange in mammals
Gaseous exchange in mammals happens as a result of inhalation and exhalation. Inhalation is breathing in air in to the lungs. Exhalation is the breathing out of air from the lungs. During inhalation the muscle of the diaphragm contract pulling the diaphragm downwards. As this happens, the external inter costal muscle contract and pull the rib cage upward and outwards. This increase volume and decreases pressure in the thorax. This makes air rush in the lungs.
During exhalation the muscles of the diaphragm resumes its dome shape. The external intercostal muscles relax pulling the rib cage inwards and downwards. This decreases volume and increases pressure. This forces air out through the bronchioles, trachea and nostrils
Gaseous Exchange Across the Alveolus
Describe gaseous exchange across the alveolus
The actual exchange of oxygen and carbon dioxide takes place in the alveoli. One mammalian lung has millions of alveoli. When we breathe air in it accumulates in the alveoli. There is higher concentration of oxygen in the alveoli than in the blood stream. The oxygen combines with hemoglobin to form oxy hemoglobin. Oxygen is then transported to the tissues
The tissue use oxygen and release carbon dioxide which diffuses in blood capillaries and combine with hemoglobin to form carbon hemoglobin. Capillaries transform this form to alveoli as it is then transported through the bronchioles trachea, glottis, pharynx, and finally nostrils into the atmosphere.
Factors Affecting Gaseous Exchange in Mammals
Outline factors affecting gaseous exchange in mammals
Factors affecting gaseous exchange in mammals include the following:
Exercise or physical activities
Age
Emotions
Temperature
Health
Carbon dioxide concentration
Hemoglobin concentration
Altitude
Gaseous Exchange in Plants
In plants gaseous exchange takes place through the stomata on the leaves and lenticels on the stem. But some plants such as mangrove also carry out gaseous exchange through breathing roots.
Parts of Plant Responsible for Gaseous Exchange
Identify parts of plant responsible for gaseous exchange
In plants gaseous exchange takes place through the stomata on the leaves and lenticels on the stem. But some plants such as mangrove also carry out gaseous exchange through breathing roots.
The Process of Gaseous Exchange in Plants
Describe the process of gseous exchange in plants
Gaseous exchange in leaves: Through stomata, atmospheric air moves in and out of the leaf. Gaseous exchange mostly takes place in the air spaces in the spongy mesophyll.
During the day, green plants carry out photosynthesis to produce glucose and this takes place within the guard cells that surround the stomata then the cell sap of the guard cells becomes hypertonic and draws in water from the neighboring cells by osmosis.
The guard cells become turgid and the stomata open whereby the air from the atmosphere such as carbon dioxide enters into the air spaces in the spongy mesophyll.
In this case carbon dioxide (CO2) is more in the air within the air space but oxygen is less. Then the carbon dioxide and oxygen diffuse in opposite direction depending on their concentration gradients (such as oxygen out and carbon dioxide in). The carbon dioxide diffuses into neighboring cells until it reaches the site for photosynthesis and oxygen moves out through the open stomata to the atmosphere.
During the night there is no light so that photosynthesis ceases and there is no production of glucose. Therefore the guard cells do not absorb water by osmosis hence the stomata remain partially closed.
However respiration process takes place at night in plants. The partially open stomata allow small amount of air to enter and accumulate in the air spaces. In this case there is more oxygen and less carbon dioxide in the air spaces compared to plant cells.
Oxygen moves into the plant cells while carbon dioxide moves into the air spaces and eventually into the atmosphere through the partially open stomata. This explains why green plants produce carbon dioxide at night and oxygen during the day.
Importance of Gaseous Exchange in PlantsExplain the importance of gaseous exchange in plants
Importance of Gaseous Exchange in Plants include the following:
It enables the plants to eliminate excess carbon dioxide at night of which if left will harm the plantsIt enables plants to obtain carbon dioxide which is one of the raw materials necessary for photosynthesisPlants obtain oxygen which is necessary for production of energy which is produced during respiration through gaseous exchange
Respiration
The concept of Respiration
Explain the concept of respiration
Respiration:Is the metabolic activity or reaction in which complex food substances are broken down step by step to release energy within a cell.
Cellular Respiration:Is a set of metabolic reaction and process that takes place in the cell of organisms to convert biochemical energy from nutrients into ATP.
NB: The reaction involved is catabolic reaction, which breaks larger molecules into smaller ones to release energy. Cellular respiration is considered as exothermic reaction. Exothermic reaction is the process whereby energy is released out.
Types of Respiration
Mention types of respiration
There are two types of respiration
Aerobic Respiration
Anaerobic Respiration
Aerobic Respiration
The Concept of Aerobic Respiration
Explain the concept of aerobic respiration
This is the combustion reaction. This means that oxygen is required in order to generate ATP. The simplified reaction of respiration of carbohydrates is C6H12O6.
Aerobic respiration – In the presence of oxygen glucose molecules are broken down into carbon dioxide water and energy
Respiration starts with glucose (usually). In aerobic and anaerobic respiration initial reactions are common as a result of which pyruvic acid is formed by breakdown of glucose.
The process is called Glycolysis or EMP Pathway (Embden-Meyerhof-Parnas Pathway). This process does not require O2although this can take place in the presence of oxygen. After this stage, the fate of pyruvic acid is different depending upon the presence or absence of oxygen.
If oxygen is present there is complete oxidation of pyruvic acid into H2O and CO2and chemical reactions through which this occurs is called Tri-Carboxylic Acid cycle (TCA Cycle) or Krebs Cycle. This cycle occurs in mitochondria. If oxygen is absent, pyruvic acid forms ethyl alcohol (C2H5OH) and CO2without the help of any cell organelle. This process is called anaerobic respiration.
Experiments on Aerobic Respiration
Carry out experiments on aerobic respiration
Respiration by living organisms can be investigated by carrying out experiments to show the production of carbon dioxide and heat.
Investigating carbon dioxide production
Limewaterturns milky in the presence of carbon dioxide. It can be used to show that exhaled air contains more carbon dioxide than inhaled air.
Carbon dioxide dissolves in water to form a weaklyacidicsolution.Hydrogencarbonate indicatoris used to show the presence of carbon dioxide in solution. It is:
red at neutralpH(no carbon dioxide)
yellow at low pH (carbon dioxide present)
Investigating heat production
The release of heat can be shown by carrying out an experiment usinggerminatingseeds. Twovacuum flasksare used:
one containing living plant material
one containing dead plant material (thecontrol)
Contents
Start temp (°C)
End temp (°C)
Temp change (°C)
Living plant material
21
29
8
Dead plant material
21
21
0
Factors which Affect the Rate of Respiration
Describe factors which affect the rate of respiration
The rate of respiration in organisms is rarely constant. There are several factors in that affect rate of respiration. These apply equally to aerobic and anaerobic respiration although the examples given here refer to aerobic respiration
Temperature:Respiration is a chemical process therefore its rate increases with increasing body temperature as an increasing in temperature increases the rate of chemical change.
Activity:All body activity requires energy. When an organism becomes active it requires more energy than when it’s inactive. Since respiration provides energy required for the activity the rate of respiration will correspondingly increase.
Body Size:Small organisms have high surface area to volume ratio. Heat loss occurs at the surface; therefore small organisms tend to lose heat more rapidly than larger ones. Small animals e.g. shrews, have to maintain higher rate of respiration than larger ones to maintain their body temperature.
Age:Young organisms are growing and as a result require more energy than older mature individual whose growth may slow down or stopped. Younger individual tend to be more physically active also. Both of these rate factors lead to increased rates of respiration in younger organism
AnAerobic Respiration
The Concept of Anaerobic Respiration
Explain the concept of anaerobic respiration
This is the process whereby energy is released in absence of oxygen although the energy outcome in anaerobic respiration is much less than aerobic respiration. Anaerobic respiration differs in plant and animal.
Anaerobic Alcoholic fermentation in plant cell and yeast
Anaerobic lactic fermentation
The Mechanism of Anaerobic Respiration
Outline the mechanism of anaerobic respiration
Anaerobic respiration differs in plant and animal.
Anaerobic Alcoholic fermentation in plant cell and yeast
Anaerobic lactic fermentation
Anaerobic Alcoholic fermentation in plant and yeast
In the presence of Alcoholic fermentation glucose molecule is broken down into ethanol and carbon dioxide and energy.
Glucose → Ethanol + Carbon dioxide + Energy
C6H12O6 → 2C2H5OH + 2CO2 + 2 ATP
Raw Material → End Product
Anaerobic Lactic Fermentation
If there is lack of oxygen carbohydrate molecule is broken down to lactic acid and energy outcome only 2ATP.
C6H12O6 (Glucose)→ C3H6O3 + 2ATP Energy (Lactic Acid)
Raw Material → End Product
A more common occurrence of lactic acid fermentation is in muscles; during exercise. During this period the respiratory surface is incapable of supplying oxygen to the molecule, which is requirement. Hence due to this lactic acid is produced. Accumulation of lactic acid will cause muscle cramp and so prevent muscles from operating.
The End Products of Anaerobic Respiration
Mention the end products of anaerobic respiration
The following are the End Product of Anaerobic Respiration:
In plants
Ethanol
Carbon dioxide
Energy
In Animals
Lactic Acid
Energy (2ATP)
Importance of Anaerobic Respiration
This process brings about fermentation. Fermentation occurs when simple sugar (glucose) is broken down by bacterial in absence of oxygen
Bacteria break down milk sugar to reduce lactic acid
Production of composite manure
Oxygen debt
During heavy exercise, oxygen supply is less than what is required by the body. As a result of anaerobic respiration taking place and lactic acid accumulates. This creates oxygen deficit.
Oxygen debt refers to the amount of oxygen required to convert lactic acid into carbon dioxide, water and energy.
An Experiment to Demonstrate the Application of Anaerobic Respiration
Carry out an experiment to demonstrate the application of anaerobic respiration
Application of Anaerobic respiration in industry and home
Alcohol brewing e.g. making beer and wine
Production of acetic acid and other acid such as citric acid
Production of biogas from cooking and lighting
Bread making process
Production of composite manure
The Difference Between Aerobic Respiration and Anaerobic Respiration
Distinguish between aerobic respiration and anaerobic respiration
Differences between Aerobic Respiration and Anaerobic Respiration include the following
Aerobic Respiration
Anaerobic Respiration
Oxygen is used up
Oxygen is not used
Larger amount of energy is released
Less amount of energy is released
Water molecules are produced
Water molecules are not produced
Takes place in mitochondria
Takes place in cytoplasm
Products produced are not harmful
Products produced are harmful example lactic acid
Infection and Diseases of the Respiratory System
Common Airborne Infections and Diseases which Affect the Respiratory System
Mention common airborne infections and diseases which affect the respiratory system
There are several airborne infections, which affect the human respiratory system. The common ones are influenza, pneumonia, common cold and tuberculosis.
Most of the airborne infections are a result of close contact with an infected person. When the sick person breathes out, coughs or sneezes, the pathogens are released into the air.
Airborne infections can be controlled by isolation of the infected patients, proper disposal of infected secretion such as sputum, living in a well-ventilated house and avoiding overcrowding especially in bedrooms.
The Causes, Symptoms, Effects and Control Measures of Common Infections and Diseases of the Respiratory System
Explain the causes, symptoms, effects and control measures of common infections and diseases of the respiratory system
Airborne infections can be controlled by isolation of the infected patients, proper disposal of infected secretion such as sputum, living in a well-ventilated house and avoiding overcrowding especially in bedrooms.
Disorders of the Respiratory System
Disorders of the Respiratory System
Mention disorders of the respiratory system
Disorders of the Respiratory System include the following:
PNEUMONIA
BRONCHITIS
ASTHMA
LUNG CANCER
EMPHYSEMA
TUBERCULOSIS
Causes, Symptoms and Effects of the Disorders of the Respiratory System
Explain causes, symptoms and effects of the disorders of the respiratory system
PNEUMONIA
Pneumonia is inflammation of the lung. It is caused by bacteria, viruses, fungi or by inhaling chemical toxins or irritants. Pneumonia is normally followed by other illnesses such as cold or flu.
SIGNS AND SYMPTOMS OF PNEUMONIA
Fever
Chills
Shortness of breath associated with pain
Increase of mucus production
Cough
PREVENTION AND TREATMENT OF PNEUMONIA
Staying warm
Avoiding overcrowded areas
Avoiding cold food and drinks, hot drinks are preferred more as they loosen secretions
Get treatment as early as possible since it is curable by antibiotics
BRONCHITIS
Bacteria, viruses and inhaling of irritating substances can cause the lining of the respiratory system to become inflamed. This causes an infection called bronchitis. Bronchitis can be acute or chronic.
ACUTE BRONCHITIS
This is caused by whooping cough or recurrent attacks of influenza; smoking can also cause acute bronchitis.
SIGNS AND SYMPTOMS OF ACUTE BRONCHITITS
Pain in the chest
Rapid breathing
Fever
Coughing
Headache
CHRONIC BRONCHITIS
Heavy smoking and recurrent acute bronchitis cause chronic Bronchitis.
SIGNS AND SYMPTOMS OF CHRONIC BRONCHITIS
Coughing with the production of thick sputum
Breathing difficulties
PREVENTION AND TREATMENT OF CHRONIC BRONCHITIS
Avoiding smoking
Avoid very smoky or dusty areas
Live in a well-ventilated house
Keep your body warm
Seek medical help
ASTHMA
Asthma is characterized by inflamed and constricted airways. The narrowing of the airways restricts the flow of air into the lungs.
Asthma can be caused by:
Allergic reactions to dust, pollen, spores or animal fur
Herediroty diseases of the respiratory system
Extremely cold weather
Frequent viral or bacteria lung infection
SIGNS AND SYMPTOMS OF ASTHMA
Narrowing of bronchioles resulting in breathing difficulties and a wheezing or hissing sound when breathing
Coughing
Shortness of breath
Excessive production of mucus
Dilation of blood vessels leading to low blood pressure, low blood pressure can be fatal
Avoid allergens (things that cause allergenic reaction)
Get treatment for respiratory infections as early as possible
Keep the body warm
Muscle relaxants in the form of sprays, pills and injections are used to prevent the narrowing of bronchitis
LUNG CANCER
The main cause of lung cancer is smoking. The nicotine in cigarette smoke stops the cilia in the trachea from expelling foreign materials leading to respiratory infection.
SIGNS AND SYMPTOMS OF LUNG CANCER
Chest pain
Breathing difficulty
Weight Loss
Persistent Cough
Abnormal Production of Mucus
PREVENTION AND TREATMENT OF LUNG CANCER
Stop smoking
There is no cure for cancer. However chemotherapy and physiotherapy are used to control the disease
EMPHYSEMA
This is a lung disease, which results from destruction of the structure supporting the alveoli leading to these collapse. This significantly reduces the surface area available for gaseous exchange.
CAUSES OF EMPHYSEMA
Mainly cigarette smoke
Air pollution
Hereditary
Old age
SIGNS AND SYMPTOMS OF EMPHYSEMA
Shortness of breath
Coughing
Obstructive lung disease
Difficulties when breathing especially during exercise
Wheezing during breathing
PREVENTION AND TREATMENT OF EMPHYSEMA
Avoid cigarette smoking and exposure to smoke
Lung surgery is usually done to relieve the symptoms
Use of medical drugs
In severe cases, lung transplant is necessary
TUBERCULOSIS
Tuberculosis is highly infections disease. The causal organism for TB is one of the strains of bacteria belonging to the Mycobacterium tuberculosis. Tuberculosis can be spread from one person to another person, when the bacteria become airborne.
SIGNS AND SYMPTOMS OF TUBERCULOSIS
Cough
Fever
Weight Loss
Loss of appetite
Disorders of the Respiratory System and HIV/AIDS
Relate disorders of the respiratory system and HIV/AIDS
Tuberculosis is the most common opportunistic infection associated with HIV worldwide. Tuberculosis is an infection by the tuberculosis bacterium that predominantly affects the lungs, but it can spread through the blood and lymph nodes to the rest of the body in people with HIV.
The disease can strike people with HIV no matter what the level of the CD4 count, which means that TB can often occur years before other problems associated with HIV develop.
Pneumocystis Carinii Pneumonia (PCP)
This is the most common opportunistic infection that occurs with AIDS the fungus that causes the PCP infection is spread through breathing or coughing. Symptoms include cough, fever, trouble breathing and loss of weight.
Cryptococci Meningitis
This is caused by fungus and it is the most common central nervous system infection associated with HIV. Meningitis is an inflammation of the membranes and fluid surrounding the brain and spinal cord.
Ways of Preventing and Controlling Disorders of the Respiratory System
Suggest ways of preventing and controlling disorders of the respiratory system
Activity 1
Suggest other ways of preventing and controlling disorders of the respiratory system.
