EDUCATIONAL TRICKS

     Hi, guyz this is my new page "Educational Tricks" this page is mainly
Created to help both science and technical students.Anything will
        An example is given bellow:
Question:
Why are air cooler less effective during
Raining season?
    Answer:
Because During the rainy reason, the atmosphere air is saturated with moisture. Therefore, the process of evaporation of water from the moist pads of the cooler slows down thereby not cooling the air blown out from the cooler.

       By Mr.V....

 
     INTRODUCTION:
 What is the respiratory system?

Your respiratory system is made up of the organs in your body that help you to breathe. Remember, that Respiration = Breathing. The goal of breathing is to deliver oxygen to the body and to take away carbon dioxide.



The primary function of the respiratory system is to supply the blood with oxygen in order for the blood to deliver oxygen to all parts of the body. The respiratory system does this through breathing. When we breathe, we inhale oxygen and exhale carbon dioxide. This exchange of gases is the respiratory system's means of getting oxygen to the blood.Respiration is achieved through the mouth, nose, trachea, lungs, and diaphragm. Oxygen enters the respiratory system through the mouth and the nose. The oxygen then passes through the larynx (where speech sounds are produced) and the trachea which is a tube that enters the chest cavity. In the chest cavity, the trachea splits into two smaller tubes called the bronchi. Each bronchus then divides again forming the bronchial tubes. 

The pathway

• Air enters the nostrils
• passes through the nasopharynx,
• the oral pharynx
• through the glottis
• into the trachea
• into the right and left bronchi, which branches and rebranches into
• bronchioles, each of which terminates in a cluster of

Braething

In mammals, the diaphragm divides the body cavity into the
            

• abdominal cavity, which contains the viscera (e.g., stomach and intestines) and the
• thoracic cavity, which contains the heart and lungs.

The inner surface of the thoracic cavity and the outer surface of the lungs are lined with pleural membranes which adhere to each other. If air is introduced between them, the adhesion is broken and the natural elasticity of the lung causes it to collapse. This can occur from trauma. And it is sometimes induced deliberately to allow the lung to rest. In either case, reinflation occurs as the air is gradually absorbed by the tissues.

Central Control Of Breathing

The rate of cellular respiration (and hence oxygen consumption and carbon dioxide production) varies with level of activity. Vigorous exercise can increase by 20–25 times the demand of the tissues for oxygen. This is met by increasing the rate and depth of breathing.

It is a rising concentration of carbon dioxide — not a declining concentration of oxygen — that plays the major role in regulating the ventilation of the lungs. Certain cells in the medulla oblongata are very sensitive to a drop in pH. As the CO₂content of the blood rises above normal levels, the pH drops
[CO₂ + H₂O → HCO₃⁻ + H⁺],
and the medulla oblongata responds by increasing the number and rate of nerve impulses that control the action of the intercostal muscles and diaphragm. This produces an increase in the rate of lung ventilation, which quickly brings the CO₂concentration of the alveolar air, and then of the blood, back to normal levels.

Local Control Of Breathing

The smooth muscle in the walls of the bronchioles is very sensitive to the concentration of carbon dioxide. A rising level of CO₂ causes the bronchioles to dilate. This lowers the resistance in the airways and thus increases the flow of air in and out.

      

          

Description of the respiratory system

The primary organs of the respiratory system are lungs, which function to take in oxygen and expel carbon dioxide as we breathe. Red blood cells collect the oxygen from the lungs and carry it to the parts of the body where it is needed. During the process, the red blood cells collect the carbon dioxide and transport it back to the lungs, where it leaves the body when we exhale.

The exchange of oxygen and carbon dioxide occurs in the alveoli, the tiny sacs that are the basic functional component of the lungs. The alveolar walls are extremely thin (about 0.2 micrometers). These walls are composed of a single layer of epithelial cells and the pulmonary capillaries.

The trachea, also called the windpipe, filters the air that is inhaled. It branches into the bronchi, which are two tubes that carry air into the lungs.

The diaphragm, a dome-shaped muscle at the bottom of the lungs, controls breathing. When a breath it taken, it flattens out and pulls forward, making more space for the lungs. During exhalation, the diaphragm expands and forces air out.

The human respiratory system is a series of organs responsible for taking in oxygen and expelling carbon dioxide. In terrestrial animals, this is accomplished by breathing. The human body needs oxygen to sustain itself. A complete lack of oxygen is known as anoxia and a decrease in oxygen is known as hypoxia. After four to six minutes brain cells without oxygen brain cells are destroyed and an extended period of hypoxia leads to brain damage and ultimately death.

Study of the respiratory system

Pulmonologists, a sub-specialty of internal medicine, treat the respiratory system, including the lungs. Because of the critical nature of the respiratory system, pulmonologists work in hospitals as well as in private practice. A pulmonologist must first be certified by the American Board of Internal Medicine and then obtain additional training in the sub-specialty.

Some milestones in the study of the respiratory system include:

• 13th century: Anatomist and physiologist Ibn Al-Nafis advances his theory that the blood must have passed through the pulmonary artery, through the lungs, and back into the heart to be pumped around the body. This is believed by many to be the first scientific description of pulmonary circulation.
• 1897: Gustav Killian uses a rigid esophagoscope to extract a pork bone from a farmer’s bronchus.
• 1898: A. Coolidge performs the first bronchoscopy in the United States at the Massachusetts General Hospital.

        Anatomy of the Respiratory System

• Nose and Nasal Cavity

The nose and nasal cavity form the main external opening for the respiratory system and are the first section of the body’s airway—the respiratory tract through which air moves. The nose is a structure of the face made of cartilage, bone, muscle, and skin that supports and protects the anterior portion of the nasal cavity. The nasal cavity is a hollow space within the nose and skull that is lined with hairs and mucus membrane. The function of the nasal cavity is to warm, moisturize, and filter air entering the body before it reaches the lungs.

• Mouth

The mouth, also known as the oral cavity, is the secondary external opening for the respiratory tract. Most normal breathing takes place through the nasal cavity, but the oral cavity can be used to supplement or replace the nasal cavity’s functions when needed. Because the pathway of air entering the body from the mouth is shorter than the pathway for air entering from the nose, the mouth does not warm and moisturize the air entering the lungs as well as the nose performs this function.

• Pharynx

The pharynx, also known as the throat, is a muscular funnel that extends from the posterior end of the nasal cavity to the superior end of the esophagus and larynx. The pharynx is divided into 3 regions: the nasopharynx, oropharynx, and laryngopharynx. The nasopharynx is the superior region of the pharynx found in the posterior of the nasal cavity.

• Larynx

The larynx, also known as the voice box, is a short section of the airway that connects the laryngopharynx and the trachea. The larynx is located in the anterior portion of the neck, just inferior to the hyoid boneand superior to the trachea. Several cartilage structures make up the larynx and give it its structure. The epiglottis is one of the cartilage pieces of the larynx and serves as the cover of the larynx during swallowing.

• Trachea

The trachea, or windpipe, is a 5-inch long tube made of C-shaped hyaline cartilage rings lined with pseudostratified ciliated columnar epithelium. The trachea connects the larynx to the bronchi and allows air to pass through the neck and into the thorax. The rings of cartilage making up the trachea allow it to remain open to air at all times. The open end of the cartilage rings faces posteriorly toward the esophagus, allowing the esophagus to expand into the space occupied by the trachea to accommodate masses of food moving through the esophagus.

• Bronchi and Bronchioles

At the inferior end of the trachea, the airway splits into left and right branches known as the primary bronchi. The left and right bronchi run into each lung before branching off into smaller secondary bronchi. The secondary bronchi carry air into the lobes of the lungs—2 in the left lung and 3 in the right lung. The secondary bronchi in turn split into many smaller tertiary bronchi within each lobe. Thetertiary bronchi split into many smaller bronchioles that spread throughout the lungs. Each bronchiole further splits into many smaller branches less than a millimeter in diameter called terminal bronchioles. Finally, the millions of tiny terminal bronchioles conduct air to the alveoli of the lungs.

• Lungs

The lungs are a pair of large, spongy organs found in the thorax lateral to theheart and superior to the diaphragm. Each lung is surrounded by a pleural membrane that provides the lung with space to expand as well as a negative pressure space relative to the body’s exterior. The negative pressure allows the lungs to passively fill with air as they relax. The left and right lungs are slightly different in size and shape due to the heart pointing to the left side of the body.

• Muscles of Respiration

Surrounding the lungs are sets of muscles that are able to cause air to be inhaled or exhaled from the lungs. The principal muscle of respiration in the human body is the diaphragm, a thin sheet of skeletal muscle that forms the floor of the thorax. When the diaphragm contracts, it moves inferiorly a few inches into the abdominal cavity, expanding the space within the thoracic cavity and pulling air into the lungs.

Defination Of Terms

• Epiglottis

Movable cartilaginous plate ensuring that the larynx closes during ingestion of food so that food cannot enter the respiratory tract

• Pharynx

Muscular membranous channel connecting the nasal cavity to the larynx and the oral cavity to the esophagus; it enables breathing, ingestion of food and speech.

• Esophagus

Muscular membranous channel of the anterior section of the digestive tract; it allows food to reach the stomach.

• Trachea

Muscular cartilaginous tract that is a continuation of the larynx; it divides into two main bronchi, each of which ends in a lung, and allows air to pass.

• Left lung

Respiratory organ divided into two lobes where blood from the pulmonary artery is cleansed of carbon dioxide and enriched with oxygen.

• Pulmonary artery

Artery carrying blood that is poor in oxygen and rich in carbon dioxide to the lungs; it is the only artery that transports oxygen-poor blood.

• Upper lobe

Section of the left lung separated from the lower lobe by the oblique fissure.

• Aorta

Main artery of the body that originates in the left ventricle of the heart and is made up of four segments; it distributes oxygenated blood throughout the body.

• Lower lobe

Section of the left lung separated from the upper lobe by the oblique fissure.

• Diaphragm

Main muscle of inspiration separating the thorax from the abdomen; its contraction increases the size of the thoracic cage and lungs, into which inhaled air is carried.

• Heart

Muscular organ divided into four chambers; its regular rhythmic contractions cause blood to circulate throughout the organism.

• Pericardium

Exterior casing of the heart formed of an inner layer adhering to the myocardium and a thick fibrous outer layer.

• Lower lobe

Section of the right lung separated from the middle and upper lobes by an oblique fissure.

• Middle lobe

Section of the right lung separated from the upper lobe by a horizontal fissure and from the lower lobe by an oblique fissure.

• Upper lobe

Section of the right lung separated from the middle lobe by a horizontal fissure and from the lower lobe by an oblique fissure.

• Right lung

Respiratory organ divided into three lobes in which blood from the pulmonary artery is cleansed of carbon dioxide and enriched with oxygen.

• Vocal cord

Muscular fold aiding speech; the vocal cords close and vibrate when air is expelled from the lungs, thereby producing sound.

• Larynx

Muscular cartilaginous duct at the upper terminal part of the trachea; it contains the vocal cords and plays a role in speech and respiration.

• Oral cavity

Secondary entry point of the respiratory system (physical effort, partial obstruction of the nose); it also helps the ingestion of food.

• Nasal cavity

Place where air inhaled through the nostrils is filtered and humidified; it also plays an olfactory role.

Parts of the Lower Respiratory Tract :

• Trachea: Also known as the windpipe this is the tube which carries air from the throat into the lungs. It ranges from 20-25mm in diameter and 10-16cm in length. The inner membrane of the trachea is covered in tiny hairs called cilia, which catch particles of dust which we can then remove through coughing. The trachea is surrounded by 15-20 C-shaped rings of cartilage at the front and side which help protect the trachea and keep it open. They are not complete circles due to the position of the oesophagus immediately behind the trachea and the need for the trachea to partially collapse to allow the expansion of the oesophagus when swallowing large pieces of food.


• Bronchioles: Tertiary bronchi continue to divide and become bronchioles, very narrow tubes, less than 1 millimeter in diameter. There is no cartilage within the bronchioles and they lead to alveolar sacs.
• Alveoli: Individual hollow cavities contained within alveolar sacs (or ducts). Alveoli have very thin walls which permit the exchange of gases Oxygen and Carbon Dioxide. They are surrounded by a network of capillaries, into which the inspired gases pass. There are approximately 3 million alveoli within an average adult lung.
• Diaphragm: The diaphragm is a broad band of muscle which sits underneath the lungs, attaching to the lower ribs, sternum and lumbar spine and forming the base of the thoracic cavity.
• Bronchi: The trachea divides into two tubes called bronchi, one entering the left and one entering the right lung. The left bronchi is narrower, longer and more horizontal than the right. Irregular rings of cartilage surround the bronchi, whose walls also consist of smooth muscle. Once inside the lung the bronchi split several ways, forming tertiary bronchi.

Human Respiratory System

Function of the Respiratory System

The function of the human respiratory system is to transport air into the lungs and to facilitate the diffusion of Oxygen into the blood stream. Its also receives waste Carbon Dioxide from the blood and exhales it.

What is the Respiratory System?

The respiratory system consists of the following parts, divided into the upper and lower respiratory tracts:

Parts of the Upper Respiratory Tract

• Mouth, nose & nasal cavity: The function of this part of the system is to warm, filter and moisten the incoming air
• Pharynx: Here the throat divides into the trachea (wind pipe) and oesophagus (food pipe). There is also a small flap of cartilage called the epiglottis which prevents food from entering the trachea
• Larynx: This is also known as the voice box as it is where sound is generated. It also helps protect the trachea by producing a strong cough reflex if any solid objects pass the epiglottis.

How the Lungs and Respiratory System Work

You usually don't even notice it, but twelve to twenty times per minute, day after day, you breathe -- thanks to your body's respiratory system. Your lungs expand and contract, supplying life-sustaining oxygen to your body and removing from it, a waste product called carbon dioxide.

The Diaphragm's Role in Breathing

Inhalation and exhalation are the processes by which the body brings in oxygen and expels carbon dioxide. The breathing process is aided by a large dome-shaped muscle under the lungs called the diaphragm.

When you breathe in, the diaphragm contracts downward, creating a vacuum that causes a rush of fresh air into the lungs.

The opposite occurs with exhalation, where the diaphragm relaxes upwards, pushing on the lungs, allowing them to deflate.

Clearing the Air

The respiratory system has built-in methods to prevent harmful substances in the air from entering the lungs.

Small hairs in your nose, called cilia, help filter out large particles. Cilia are also found along your air passages and move in a sweeping motion to keep the air passages clean. But if harmful substances, such as cigarette smoke, are inhaled, the cilia stop functioning properly, causing health problems like bronchitis.

Mucus produced by cells in the trachea and bronchial tubes keeps air passages moist and aids in stopping dust, bacteria and viruses, allergy-causing substances, and other substances from entering the lungs.

Impurities that do reach the deeper parts of the lungs can be moved up via mucous and coughed out or swallowed.

Diseases of the Lungs :

Pneumonia

Pneumonia is an infection of the alveoli. It can be caused by many kinds of both bacteria (e.g., Streptococcus pneumoniae) and viruses. Tissue fluids accumulate in the alveoli reducing the surface area exposed to air. If enough alveoli are affected, the patient may need supplemental oxygen.

Asthma

In asthma, periodic constriction of the bronchi and bronchioles makes it more difficult to breathe in and, especially, out. Attacks of asthma can be

• triggered by airborne irritants such as chemical fumes and cigarette smoke
• airborne particles to which the patient is allergic.

Emphysema

In this disorder, the delicate walls of the alveoli break down, reducing the gas-exchange area of the lungs. The condition develops slowly and is seldom a direct cause of death. However, the gradual loss of gas-exchange area forces the heart to pump ever-larger volumes of blood to the lungs in order to satisfy the body's needs. The added strain can lead to heart failure.



The immediate cause of emphysema seems to be the release of proteolytic enzymes as part of the inflammatory process that follows irritation of the lungs. Most people avoid this kind of damage during infections, etc. by producing an enzyme inhibitor (a serpin) called alpha-1 antitrypsin. Those rare people who inherit two defective genes for alpha-1 antitrypsin are particularly susceptible to developing emphysema.

Chronic Bronchitis



Any irritant reaching the bronchi and bronchioles will stimulate an increased secretion of mucus. In chronic bronchitis the air passages become clogged with mucus, and this leads to a persistent cough. Chronic bronchitis is usually associated with cigarette smoking.

Chronic Obstructive Pulmonary Disease (COPD)

Irritation of the lungs can lead to asthma, emphysema, and chronic bronchitis. And, in fact, many people develop two or three of these together. This constellation is known as chronic obstructive pulmonary disease (COPD).

Among the causes of COPD are

•     cigarette smoke (often)
•     cystic fibrosis (rare)

Cystic fibrosis is a genetic disorder caused by inheriting two defective genes for the cystic fibrosis transmembrane conductance regulator (CFTR), a transmembrane protein needed for the transport of Cl− and HCO3− ions through the plasma membrane of epithelial cells. Defective secretion of HCO3− lowers the pH of the fluid in the lungs making it more hospitable to colonization by inhaled bacteria. The resulting inflammation leads to the accumulation of mucus which plugs the airways and hampers the ability of ciliated cells to move it up out of the lungs. All of this damages the airways — interfering with breathing and causing a persistent cough. Cystic fibrosis is the most common inherited disease in the U.S. white population.

Lung Diseases Affecting the Air Sacs (Alveoli)

The airways eventually branch into tiny tubes (bronchioles) that dead-end into clusters of air sacs called alveoli. These air sacs make up most of the lung tissue. Lung diseases affecting the alveoli include:

• Pneumonia: An infection of the alveoli, usually by bacteria.
• Tuberculosis: A slowly progressive pneumonia caused by the bacteriaMycobacterium tuberculosis.
• Emphysema results from damage to the fragile connections between alveoli. Smoking is the usual cause. (Emphysema also limits airflow, affecting the airways as well.)
• Pulmonary edema: Fluid leaks out of the small blood vessels of the lung into the air sacs and the surrounding area. One form is caused by heart failure and back pressure in the lungs' blood vessels; in another form, direct injury to the lung causes the leak of fluid.
• Lung cancer has many forms, and may develop in any part of the lungs. Most often this is in the main part of the lung, in or near the air sacs. The type, location, and spread of lung cancer determines the treatment options.




• Acute respiratory distress syndrome (ARDS): Severe, sudden injury to the lungs caused by a serious illness. Life support with mechanical ventilation is usually needed to survive until the lungs recover.
• Pneumoconiosis: A category of conditions caused by the inhalation of a substance that injures the lungs. Examples include black lung disease from inhaled coal dust and asbestosis from inhaled asbestos dust.

Lung Diseases Affecting the Interstitium

The interstitium is the microscopically thin, delicate lining between the lungs' air sacs (alveoli). Tiny blood vessels run through the interstitium and allow gas exchange between the alveoli and the blood. Various lung diseases affect the interstitium:

• Interstitial lung disease (ILD): A broad collection of lung conditions affecting the interstitium. Sarcoidosis, idiopathic pulmonary fibrosis, and autoimmune disease are among the many types of ILD.
• Pneumonias and pulmonary edemas can also affect the interstitium.

Physiology of the Respiratory System

• Pulmonary Ventilation

Pulmonary ventilation is the process of moving air into and out of the lungs to facilitate gas exchange. The respiratory system uses both a negative pressure system and the contraction of muscles to achieve pulmonary ventilation. The negative pressure system of the respiratory system involves the establishment of a negative pressure gradient between the alveoli and the external atmosphere. The pleural membrane seals the lungs and maintains the lungs at a pressure slightly below that of the atmosphere when the lungs are at rest. This results in air following the pressure gradient and passively filling the lungs at rest. As the lungs fill with air, the pressure within the lungs rises until it matches the atmospheric pressure.

• External Respiration

External respiration is the exchange of gases between the air filling the alveoli and the blood in the capillaries surrounding the walls of the alveoli. Air entering the lungs from the atmosphere has a higher partial pressure of oxygen and a lower partial pressure of carbon dioxide than does the blood in the capillaries. The difference in partial pressures causes the gases to diffuse passively along their pressure gradients from high to low pressure through the simple squamous epithelium lining of the alveoli. The net result of external respiration is the movement of oxygen from the air into the blood and the movement of carbon dioxide from the blood into the air.

• Internal Respiration

Internal respiration is the exchange of gases between the blood in capillaries and the tissues of the body. Capillary blood has a higher partial pressure of oxygen and a lower partial pressure of carbon dioxide than the tissues through which it passes. The difference in partial pressures leads to the diffusion of gases along their pressure gradients from high to low pressure through the endothelium lining of the capillaries. The net result of internal respiration is the diffusion of oxygen into the tissues and the diffusion of carbon dioxide into the blood.

• Transportation of Gases

The 2 major respiratory gases, oxygen and carbon dioxide, are transported through the body in the blood. Blood plasma has the ability to transport some dissolved oxygen and carbon dioxide, but most of the gases transported in the blood are bonded to transport molecules. Hemoglobin is an important transport molecule found in red blood cells that carries almost 99% of the oxygen in the blood. Hemoglobin can also carry a small amount of carbon dioxide from the tissues back to the lungs.

• Homeostatic Control of Respiration

Under normal resting conditions, the body maintains a quiet breathing rate and depth called eupnea. Eupnea is maintained until the body’s demand for oxygen and production of carbon dioxide rises due to greater exertion. Autonomic chemoreceptors in the body monitor the partial pressures of oxygen and carbon dioxide in the blood and send signals to the respiratory center of the brain stem.

               Keep learning as it change....Mr.Very