Lecture 13 Flashcards
(89 cards)
1
Q
Functions of the respiratory system
A
Pulmonary ventilation (Gas exchange)
* Supply of O2, Removal of CO2
Vocalisation (speaking)
Olfaction (smelling)
Biotransformation (metabolism)
* Bronchiolar secretoglobin cells (BSCs) > alveolar type II cells > macrophages, endothelial cells
ACE
*Angiotensin-converting enzyme (ACE) is a central component of the renin–angiotensin system (RAS), which controls blood pressure by regulating the volume of fluids in the body. It converts the hormone angiotensin I to the active vasoconstrictor angiotensin II. Therefore, ACE indirectly increases blood pressure by causing blood vessels to constrict. ACE inhibitors are widely used as pharmaceutical drugs for treatment of cardiovascular diseases.
Removal of inhaled particulate matter
2
Q
Regions of the respiratory system
A
- Nasal cavities
- Pharynx (throat)
- Larynx (voice box)
- Trachea (wind-pipe)
- Lungs
3
Q
Respiratory meaning
A
refers to the overall process of breathing (all parts of the breathing system, including lungs)
4
Q
Pulmonary meaning
A
specifically refers to the lungs (function, disease, etc)
5
Q
The nasal cavities
A
*Nasal cartilages
*Anterior nares (nostrils)
*Choanae (posterior nares)
*Olfactory receptors
* Cribriform plate of the ethmoid bone
* Nasolacrimal aperture
* Nasal septum
* Nasal conchae (shelves)
* Paranasal air sinuses
6
Q
Nasal cartilages
A
- Structures within the nose that provide form and support to the nasal cavity. The nasal cartilages are made up of a flexible
material
7
Q
Anterior nares (nostrils)
A
- Allow air to enter the nose and pass into the nasal cavity. Individually, each opening is referred to as an anterior naris
- Olfactory receptors
- Cribriform plate of the ethmoid bone
- Nasolacrimal aperture
- Nasal septum
- Nasal conchae (shelves)
- Paranasal air sinuses
8
Q
Choanae (posterior nares)
A
- Openings found at the back of the nasal passage between the nasal cavity and the throat
9
Q
What are olfactory receptors
A
- Olfactory receptors (ORs) belong to the G-protein-coupled receptor family and play a critical role in recognizing thousands of odorant molecules in the olfactory sensory system
- Any odor stimulus is initially represented as activation of one to many different olfactory receptors
- Some receptors, in particular, those for pheromones, show very high specificity
10
Q
Cribriform plate of the ethmoid bone
A
- Lies within the ethmoidal notch of the frontal bone and forms the roof of the nasal cavity
11
Q
Nasolacrimal aperture
A
- The purpose of the nasolacrimal system is to drain tears from the ocular surface to the lacrimal sac and, ultimately, the nasal cavity
12
Q
Nasal septum
A
It is the bone in the nose that divides the nasal cavity (inside your nose) into a right and left side
13
Q
Nasal conchae (shelves)
A
- Nasal concha, also called Turbinate, or Turbinal
- Three bony shelves called the inferior, middle and superior nasal conchae are
attached to the lateral walls and by projecting into the cavities, they divide both nasal
cavities into four air channels - They increase the surface area of these cavities, thus providing for rapid warming and
humidification of air as it passes to the lungs.
14
Q
Paranasal air sinuses
A
- Small hollow spaces in the bones around the nose. The prime function of the paranasal
sinuses is to protect the organism, mostly by humidifying the inhaled air and facilitating the immune response of the respiratory system
15
Q
Parts of the pharynx
A
- Nasopharynx (auditory tubes)
- Oropharynx
- Laryngopharynx
16
Q
Nasopharynx (auditory tubes)
A
- The main function of your nasopharynx is to connect your nasal passages to the rest of your respiratory system. This allows air to get from your nose to your lungs.
- Also controls pressure between nasopharynx and middle ear.
17
Q
Oropharynx
A
- The middle part of the throat connects to the oral cavity (mouth) and allows air, food and fluid to pass through
18
Q
Laryngopharynx
A
- The bottom part of the throat is near the larynx (or voice box). It regulates the passage of air to the lungs and food and fluid to the esophagus (the hollow, muscular tube that
connects the throat to the stomach)
19
Q
The larynx (“voice box”)
A
- Larynx has several functions including:
- Creating vocal sounds and preventing food and other particles from getting into trachea, lungs and the rest of your respiratory system.
20
Q
The trachea (“wind-pipe”)
A
- The trachea is a key part of respiratory system.
- The trachea is composed of about 20 rings of tough cartilage. The back part of each ring is made of muscle and connective tissue. Moist, smooth tissue called mucosa lines the inside of the trachea. The trachea widens and lengthens slightly with each breath in, returning to its resting size with each breath out.
- It is lined with cells that produce mucus. This
mucus keeps allergens, dust particles or other
debris out of lungs. - Tracheobronchomalacia (TBM) is a condition
caused by a weak airway that collapses when
the patient breathes. - TBM in adults can be caused by exposure to
toxic gases such as mustard gas, exposure to
secondhand smoke (inhaled accidentally).
21
Q
Mucous membrane
A
- The airway surface liquid (ASL), often referred to as mucus, is a thin layer of fluid covering the luminal surface of the airway. The major function of mucus is
to protect the lung through mucociliary clearance against foreign particles and chemicals entering the lung. - Hairlike structures called cilia line the mucous membrane and move the particles trapped in the mucus out of the nose.
- Airway mucus traps inhaled toxins and transports them out of the lungs by means of ciliary beating and cough. Paradoxically, although a deficient mucous
barrier leaves the lungs vulnerable to injury, excessive mucus or impaired clearance contributes to the pathogenesis of all the common airway diseases. - Infections such as the flu, acute bronchitis
(inflammation of the airways), and pneumonia (inflammation of the lungs) can cause the airways to make extra mucus.
22
Q
Specialised cells
A
- Ciliated cells
- Mucous cells
- Basal cells
23
Q
Ciliated cells
A
- Ciliated cell provides the propelling force for the transport of mucus along the airways
24
Q
Mucous cells
A
- Scattered throughout the cilia are goblet cells that secrete mucus which helps protect the lining of the bronchus and trap microorganisms and particles
25
Basal cells
* Basal cells provide an attachment site for ciliated and goblet cells to the basal lamina. They are also candidate stem cells in the conducting airways, responsible for normal cell replacement
26
Structure and location of the lungs
The right lung consists of three lobes: the right upper lobe, the right middle lobe, and the right lower lobe.
The left lung consists of two lobes: the left upper lobe and the left lower lobe.
27
Parts of the lungs
Apex of lung
Base of lung
* Each lung has a base resting on the diaphragm
Root (hilum) of lung
* Location where primary Bronchus, Bronchial
Artery, Pulmonary Artery, Pulmonary vein, Nerve and Lymphatic vessels enter and leave the lung
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What is the respiratory zone and conducting zone
Respiratory zone is found deep inside the lungs. This zone corresponds to the lung parenchyma and includes the respiratory bronchioles, alveolar ducts, and alveoli.
All of the airway sections, before respiratory zone, are called conducting zone. The major functions of the conducting zone are to provide a route for incoming and outgoing air, remove debris and pathogens from the incoming air, and warm and humidify the incoming air.
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Alveoli
* Alveoli represent the most distal portion of the respiratory tract.
* There are approximately 500 million alveoli in the human body.
* Each alveolus is separated from the other by an alveolar septum, which contains the pulmonary capillaries participating in gas exchange and connective tissue.
* Each alveolus consists mostly of three types of cell populations:
1. Type I pneumocytes
2. Type II pneumocytes
3. Alveolar macrophages
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Type I pneumocytes
* Facilitate gas exchange
* Maintain ion and fluid balance within the alveoli
* Communicate with type II pneumocytes to secrete surfactant in response to stretch
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Type II pneumocytes
* Produce and secrete pulmonary surfactant - surfactant is a vital substance that reduces surface tension, preventing alveoli from collapsing.
* Expression of immunomodulatory proteins that are necessary for host defense
* Regulates the movement of water across epithelium
* Regeneration of alveolar epithelium after injury
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Alveolar macrophages
* Play an essential role in our immune system. They collect inhaled particles from the
environment, such as coal, silica, and asbestos, and microbes, including viruses,
bacteria, and fungi.
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Gas exchange
* Upon inhalation, the diaphragm contracts and flattens and the chest cavity enlarges. This contraction creates a vacuum, which
pulls air into the lungs. Upon exhalation, the diaphragm relaxes and returns to its domelike shape, and air is forced out of the
lungs.
* A nerve (phrenic nerve) automatically and involuntarily control the contractions and relaxation of the diaphragm to maintain a
steady blood-oxygen level. It can adjust the contraction frequency as needed when indicated by the brain.
* The skeletal muscle of diaphragm can also be controlled voluntarily by an individual, for example, when performing meditative breathing
34
Three processes are essential for the transfer of gas (oxygen) from the outside air to the blood flowing through the lungs...
* Ventilation is the process by which air moves in and out of the lungs.
* Diffusion is the spontaneous movement of gases, without the use of
any energy or effort by the body, between the alveoli and the capillaries in the lungs.
* Perfusion is the process by which the cardiovascular system pumps blood throughout the lungs
35
The pulmonary artery carries...
deoxygenated blood from the heart to the lungs, where it travels through pulmonary capillaries, picking up oxygen and releasing
carbon dioxide. The oxygenated blood then leaves the lungs through pulmonary veins. Gas exchange occurs by diffusion across cell membranes. Diffusion allows the spontaneous movement of gases, without the use of any energy.
36
Carbonic anhydrase enzyme
in red blood cells, during external and
internal respiration, catalyzes the reaction between water and carbon dioxide (in body it converts carbon dioxide to carbonic acid and
bicarbonate ions, then in lungs converts them back to carbon dioxide)
37
External respiration occurs...
occurs as a function of partial pressure differences in oxygen and carbon dioxide between the alveoli and the blood in the pulmonary capillaries.
38
The Great Smog of 1952
* Smog is a type of air pollution, created by industrial output and natural weather patterns. London’s reliance on coal-fired power plants for electricity and heat, and
diesel-powered buses for public transportation, contributed to the Great Smog. It last almost a week and cost between 4,000-10,000 lives.
* The sulfur dioxide, carbon dioxide, and
smoke particles ended up choking many
people to death.
* Smog is still a problem in cities such as Mexico City, Mexico; Beijing, China; and Los Angeles, United States.
39
Factors Affecting Toxicity (particle size)
* Inhaled particles are deposited according to
their size.
* Particles over 10 μm are deposited largely
in the nose and upper airways because of
turbulent air flow;
* particles of 1 to 10 μm lodge in the trachea
and bronchi by impaction;
* smaller particles are deposited in the
terminal airways and alveoli.
* The most dangerous particles smaller than
5 μm in diameter; these penetrate to the
respiratory bronchioles and air spaces,
where they impact or settle.
* The toxic potential of particles affecting
the lung is influenced by the number of
particles retained in the lung and airways,
the size and shape of the particles, and the
solubility and cytotoxicity of the particles.
40
Factors Affecting Toxicity (solubility)
* Highly water-soluble gases such as sulfur dioxide or formaldehyde go into solution in the nasal fluids and are, therefore, almost completely extracted in the upper airway in resting subjects during any brief exposure.
* The solubility of a gas in water is the major characteristic in determining the relative toxicity of the gas.
* Inhaled toxicants that do not exert immediate toxic effects can pass through the
lung, reach the capillaries, and be transported by the blood to other tissues where they can cause injury.
* Inhaled drugs must be dissolved in the lung lining fluid for subsequent diffusion,
cellular uptake, absorption, and interaction with the receptors. The difference in the solubility and the dissolution rate of the drug compounds may result in different clearance pathways.
* After inhalation, water-soluble drugs may quickly dissolve in the lung lining fluid and diffuse through the airway epithelium, and disappear from the lungs by absorption.
* In the case of poorly water-soluble drug, sufficient dissolving of the inhaled drug
particles might not be reached due to the limited volume of lung lining fluid.
41
The mechanisms of particle deposition in respiratory tract
* Deposition means the event of a particle to adhere or stick to a surface.
* Generally, for the description of the respiratory deposition of particles, three components are required:
geometrical model of the lung, aerodynamic characteristics, and particle behavior.
* Depending on the aerodynamic diameter (AD) of inhaled particles, taking their shape and density into account, five deposition mechanisms are described:
1. Impaction
2. Sedimentation
3. Diffusion
4. Interception
5. Electrostatic precipitation, which is related to particle charge
42
The mechanisms of particle deposition in respiratory tract- Impaction
* Large-sized particles with higher momentum simply do not follow the curvature of the air stream due to inertia and deposit on
the airway wall. Because momentum is the product of mass and velocity, inertial impaction is important for large particles,
usually greater than 1 μm in size. Deposition by impaction increases both with growing particle sizes and flow rates
43
The mechanisms of particle deposition in respiratory tract- Sedimentation
* Sedimentation is due to the dominating gravitational force acting on the inhaled particles over the air resistance. Thus, as a
result of balancing between the gravitational force and drag force of air, particle may deposit on lower surfaces of the airway.
This mechanism is important for particle sizes greater than about 0.5 μm and becomes dominant in the Bronchiolar region and
alveolar-interstitial region where air flow decelerates.
44
The mechanisms of particle deposition in respiratory tract- Diffusion
* Deposition by diffusion is caused by Brownian motion or a larger diffusion coefficient. Diffusion is the deposition mechanism for small particles (< 0.5 μm) due to collision with air molecules. Deposition by diffusion increases with decreasing particle size and flow rate
45
The mechanisms of particle deposition in respiratory tract- Interception
* Deposition by interception occurs when a particle comes close enough to an airway wall that an edge touches its surface. It is an
important mechanism for elongated particles such as fibers for which the ratio between length and diameter is large.
46
The mechanisms of particle deposition in respiratory tract- Electrostatic precipitation, which is related to particle charge
* Removes particles using electrical energy. Charged particles are attracted to the opposite charge. Free ions are deposited very
effectively in the upper airways whereas charged particles penetrate to the deeper lungs.
47
What is asthma
Asthma is a condition in which your airways narrow and swell and may produce extra mucus. This can make breathing difficult and trigger coughing, a whistling sound (wheezing) when you breathe out and shortness of breath.
Asthma is thought to be caused by a combination of genetic and environmental factors. Environmental factors include exposure to air pollution and allergens. Other potential triggers include medications such as aspirin and beta blockers.
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What is airway hyperresponsiveness (AHR)
Airway hyperresponsiveness (AHR) is an abnormal condition affecting a person's air passage. In AHR, the lungs' airways become highly sensitive and narrow in response to certain stimuli. Narrowing of the airway makes breathing difficult. AHR can lead to various respiratory problems, such as asthma and chronic obstructive pulmonary disease (COPD).
The causes of AHR:
*Genetics
*Smoking
*Allergens
*Air pollution
*Occupational exposure
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House Dust Mite (HDM)
induced Asthma
* Asthma is related to airway inflammation
and oxidative stress. High levels of reactive oxygen and nitrogen species can induce cytotoxic DNA damage.
* Allergic asthma, the most common form
of asthma, can be triggered by allergens,
such as house dust mite (HDM).
* HDM challenge increased lung levels of
oxidative damage to proteins (3-
nitrotyrosine), lipids (8-isoprostane), and
nucleic acid (8-oxoguanine).
* Bronchial epithelial cells a defect in DNA
repair exacerbates inflammatory responses
50
Bronchospasms happen when...
the muscles that line your bronchi (airways in your lungs) tighten. This results in wheezing, coughing, etc
51
Transient receptor potential (TRP)
* Transient receptor potential ankyrin-1 (TRPA1) is a ligand-gated cation channel that responds to endogenous and exogenous irritants. TRPA1 is expressed on multiple cell types throughout the lungs.
* Studies found evidence that the ion channel TRPA1 is involved in sensory neural responses to mustard oil, allicin, cold temperatures, pungent natural-compounds,
chemical and environmental irritants.
52
Pulmonary edema is a condition caused by...
too much fluid in the lungs. This fluid collects in the many air sacs in the lungs, making it difficult to breathe
* Pulmonary Oedema
* It can be a life-threatening condition in some patients with high mortality
53
Acute lung toxicity
* Large particles and water-soluble gases and vapors are likely to have their initial irritant effects in the mucous membranes of the upper airway (Nasal Irritation)
* Mucosal toxicity can be exhibited by decreased cell production or increased cell loss, which can lead to atrophy (loss of a part or tissue)
In people smooth muscles often tighten in reaction to certain things. When this happens, the airways become narrower, which blocks the flow of air and makes it harder to breathe.
* Bronchoconstriction
* Wheezing, shortness of breath
* Pulmonary edema is a condition caused by too much fluid in the lungs. This fluid collects in the many air sacs in the lungs, making it difficult to breathe
54
Acrolein
*Acrolein (systematic name: propenal) is the simplest unsaturated aldehyde. It is a colorless liquid with a piercing, acrid smell
* Signs and symptoms resulting from inhalation exposure to airborne acrolein may include irritation of the nose, throat and lungs, pulmonary edema, lung hemorrhage, and death.
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Allyl isothiocyanate
*Allyl isothiocyanate (AITC) is an organosulfur compound (formula CH 2 CHCH 2 NCS). The colorless oil is responsible for the pungent taste of mustard, radish, horseradish, and wasabi. This pungency and the lachrymatory effect of AITC are mediated through the TRPA1 and TRPV1 ion channels.
* Inhalation causes respiratory tract irritation. May cause asthmatic attacks due to allergic
sensitization of the respiratory tract. Vapors may cause dizziness or suffocation.
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Inhalation of chlorine
* Inhalation of higher concentrations of chlorine gas (>15 ppm) can rapidly lead to
respiratory distress with airway constriction and accumulation of fluid in the lungs
(pulmonary edema)
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Hydrogen peroxide inhalation
Inhalation of hydrogen peroxide causes irritation to the nose, throat and respiratory
tract. In very severe cases bronchitis or pulmonary oedema may occur, which can
potentially be fatal
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Styrene exposure
* Many reports have linked exposure to styrene vapor in occupational settings to various forms of non-malignant pulmonary disorders including bronchiolitis, hypersensitivity pneumonitis, and occupational asthma.
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Naphthalene exposure
Human exposure to naphthalene, an acute lung toxicant is primarily through inhalation.
Acute lung toxicity and carcinogenesis. short- term exposure of humans to naphthalene
by inhalation, ingestion, and dermal contact is associated with hemolytic anemia. When
you have anemia, your blood can't carry enough oxygen to your body
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Ochratoxin A (OTA) exposure
Ochratoxin A (OTA) exposure can happen via ingestion and
inhalation
Respiratory distress and pulmonary edema
Molds associated with the production of OTA include:
* Aspergillus ochraceus
* Aspergillus niger
* Aspergillus carbonarius
* Penicillium verrucosum
* Species of Petromyces
* Species of Neopetromyces
Inhalation exposure can happen in water damaged indoor environments found to have elevated levels of mold including species of Aspergillus and Penicillium.
OTA has been detected in blood, urine, and breast milk.
Studies showed elevated concentrations of OTA in the urine of individuals exposed to water-damaged buildings versus unexposed controls.
Wine, beer, coffee, dried vine fruit, grape juices, pork, poultry, dairy, spices, and chocolate are foods that can be contaminated with OTA.
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Acute Respiratory Distress Syndrome (ARDS)
Acute respiratory distress syndrome (ARDS) is a life-threatening condition where the lungs cannot provide the body's vital organs with
enough oxygen.
While a range of drugs and chemicals such as methotrexate, cresol, acryloyl chloride, chlorine-containing bleach, etc, can cause ARDS, infections are still considered as the most common risk factors for ARDS.
SARS-CoV-2 (COVID-19)
* Patients develop dyspnea and hypoxemia and rapidly progress to acute respiratory distress syndrome (ARDS) and multi-organ failure.
* They required mechanical ventilation.
* The severity of ARDS correlates directly with
mortality, and currently, there are no effective
pharmacological treatments for ARDS, as painfully highlighted by the COVID-19 pandemic.
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Renin-angiotensin-aldosterone system (RAAS)
Infection typically starts in the epithelia of the
upper respiratory tract before spreading to the alveoli, where alveolar type II cells are known to express high levels of ACE.
Following SARS-CoV-2 infection, it is widely
accepted that the formation of the ACE/virus
complex results in reduced ACE activity and
expression. This functional loss of ACE activity
leads to a dysregulation in the renin-
angiotensin-aldosterone system (RAAS)
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Chronic lung toxicity (chronic Bronchitis)
* Chronic bronchitis is long-term inflammation of the bronchi.
* It is common among smokers.
* People with chronic bronchitis tend to get lung infections more easily.
* Airway inflammation = restricted airflow
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Chronic lung toxicity (Emphysema)
* Emphysema is a chronic lung condition in which the air sacs (alveoli) may be: Collapsed;
Destroyed; Narrowed; Overinflated; Stretched
* Overinflation of the air sacs is a result of a breakdown of the alveoli walls.
* It causes a decrease in respiratory function and breathlessness.
* Damage to the air sacs can't be fixed. It causes permanent holes in the lower lung tissue.
* Increased airspaces = wall destruction
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Chronic Bronchitis and Emphysema
Both Chronic Bronchitis AND Emphysema are Chronic Obstructive Pulmonary Diseases (COPD).
* COPD affects more than 15 million Americans. More than 150,000 Americans die of COPD each year (that is 1 death every 4 minutes!)
* Around 86% of COPD deaths in UK are caused by smoking
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Interstitial Lung Disease: Pulmonary Fibrosis
Interstitial lung disease refers to a group of about 100 chronic lung disorders characterized by inflammation and scarring that make it hard for the lungs to get enough oxygen. The scarring is called pulmonary fibrosis.
The common link between the many forms of the disease is that they all begin with inflammation:
* Bronchiolitis: inflammation of the small airways (bronchioles).
* Alveolitis: inflammation of the air sacs where oxygen and carbon dioxide exchange in the blood takes places (alveoli).
* Vasculitis: inflammation that involves the small blood vessels (capillaries).
Fibrosis leads to permanent loss of your lung
tissue’s ability to carry oxygen. The air sacs, as
well as the lung tissue around the air sacs and the lung capillaries, are destroyed when the scar tissue forms.
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Pulmonary Fibrosis causes
The cause of interstitial lung disease is not known. Major contributing factors include:
* Smoking
* Certain drugs or medicines
* Exposure to substances at work or in the
environment such as organic or inorganic dusts
* Certain connective tissue or collagen diseases and sarcoidosis
* Family history
* Radiation treatment
Average survival is between three to five years. There is no cure for pulmonary fibrosis (PF). People may benefit from a drug that slows the progression of the disease. Oxygen therapy and pulmonary rehabilitation are key components of maintaining a good quality of life with PF. Lung transplant may increase life expectancy.
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Types of Interstitial Lung Disease- Asbestosis
* Asbestosis is a chronic (long-term) lung condition caused by prolonged exposure to asbestos.
Mesothelioma: It's usually linked to asbestos exposure. a type of cancer that develops in the lining that covers the outer surface of some of the body's organs.
* The most common use of asbestos was corrugated asbestos cement roofing primarily for outbuildings, warehouses, and garages.
* Due to the risks to health following inhalation exposure to asbestos the importation of blue and brown asbestos has been banned in the UK since 1985. This ban was extended to include white asbestos in
1999.
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Types of Interstitial Lung Disease- Byssinosis (endotoxin in plant fibres)
* It is caused by breathing in cotton dust or dusts from other vegetable fibers such as flax, hemp, or sisal while at work.
* Byssinosis is also called brown lung; over time the dust accumulates in the lung, producing a typical discoloration that
gives the disease its common name.
* Recent studies identified that endotoxin released from the cell wall of bacteria within textile fibers contributes to byssinosis symptoms.
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Types of Interstitial Lung Disease- Berylliosis (dusts/fumes of)
also known as chronic beryllium disease (CBD), is a granulomatous disease
caused by exposure to beryllium.
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Types of Interstitial Lung Disease- Coal Workers’ Pneumoconiosis (coal dust)
* CWP is defined as parenchymal lung disease secondary to the inhalation of
coal mine dust, which includes both carbonaceous (coal) and noncarbonaceous minerals such as silica and silicates.
* black lung disease
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Types of Interstitial Lung Disease- (silica dust)
a long-term lung disease caused by inhaling large amounts of crystalline silica dust, usually over many years.
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Types of Interstitial Lung Disease- Flock Workers’ Lung (fabric fibres)
an occupational lung disease caused by exposure to flock, small fibers that are glued to a backing in order to create a specific texture.
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Types of Interstitial Lung Disease- Farmers’ Lung (hay dust, mould, etc)
a type of hypersensitivity pneumonitis that is caused by precipitants such as moldy hay or straw.
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Lung Cancer
* Cancer that starts in the lung is called primary lung cancer. Cancer that spreads to your lungs from somewhere else in your body is called secondary lung cancer
76
There are different types of primary lung cancer and they are divided into two main groups
small cell lung cancer (SCLC)
* (around 15 to 20%)
non small cell lung cancer (NSCLC)
* The most common type is non small cell lung cancer (around 80 to 85%)
* Adenocarcinoma: This is the most common type and starts in the mucus making gland
cells in the lining of your airways.
* Squamous-cell carcinoma: This type develops in the flat cells that cover the surface of your airways. It tends to grow near the centre of the lung.
* Large-cell carcinoma: The cancer cells appear larger than a typical cell under the
microscope.
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Polycyclic aromatic hydrocarbons (PAHs)
Polycyclic aromatic hydrocarbons (PAHs) can cause breast cancer, childhood cancers and lung cancer. CYP1A1 enzymes bioactivate PAHs into reactive metabolites that induce mutagenic/carcinogenic DNA adducts
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Pulmonary Vascular Disease (PVD)
Pulmonary vascular disease (PVD) is a broad term including any condition that affects the blood vessels within the lungs. These vessels take blood that is depleted of oxygen to the lungs from the right side of the heart. Deoxygenated blood travels through the pulmonary arteries where oxygen is taken up.
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Pulmonary Arterial Hypertension (PAH)
* PAH is one form of a broader condition known as pulmonary hypertension, which is high blood pressure in the lungs. In PAH, this increased pressure in the vessels is caused by obstruction in the small arteries in the lung for a variety of reasons.
* Amphetamines may lead to PAH due to the release of serotonin, which causes pulmonary
vasoconstriction and the proliferation of smooth muscle cells.
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Pulmonary Veno-Occlusive Disease (PVOD)
* Pulmonary veno-occlusive disease (PVOD) is a very rare disease. It is characterized by the
blockage (occlusion) of the blood vessels that carry oxygen-rich (oxygenated) blood from the lungs to the heart (the pulmonary veins). The occlusion is caused by a buildup of abnormal fibrous tissue in the small veins in the lungs, which narrows the vessels and impairs blood flow. Because blood flow through the lungs is difficult, pressure rises in the vessels that carry blood that needs to be oxygenated to the lungs from the heart.
* Monocrotaline (MCT), a pyrrolizidine alkaloid, derived from the seeds of the Crotalaria spectabilis plant, causes veno-occlusive disease of the liver and pulmonary lesions in a dose-dependent manner. MCT should first metabolized into the toxic metabolite MCT pyrrole (MCTP)
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Spirometry
A spirometer is a device used to check lung function. Spirometry is one of the simplest, most common tests.
It may be used to:
* Determine how well the lungs receive, hold, and move air
* Look for lung disease
* See how well treatment is working
* Determine the severity of a lung disease
* Find out whether the lung disease is restrictive (decreased airflow) or obstructive (disruption of airflow)
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The single-breath nitrogen washout test
It sometimes called the single-breath oxygen test, which is designed to assess the uniformity of gas distribution in the lungs and the behavior of the dependent airways. The patient takes a single vital capacity inspiration of pure oxygen and then exhales slowly to
residual volume (RV). The exhaled volume and the nitrogen concentration in that volume are measured to obtain the nitrogen-
washout curve.
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Bronchial Challenge Test
A bronchial challenge test can also be called an airway provocation test or direct challenge test. It involves breathing in a powder or mist
that can irritate the airways and make them get narrower like how an asthma trigger would irritate the airways. The test will find out how sensitive your airways are. People with sensitive airways will be affected by a much lower dose of the powder or mist than people with healthy airways.
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Peak flow monitoring
This device is used to measure the how fast you can blow air out of the lungs. Disease-related changes can cause the large airways in the lungs to slowly narrow. This will slow the speed of air leaving the lungs. This measurement is very important in evaluating how well or how poorly the disease is being controlled
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Chest X-rays
Chest X-rays can detect cancer, infection or air collecting in the space around a lung, which can cause the lung to collapse. They can also show chronic lung conditions, such as emphysema or cystic fibrosis, as well as complications related to these conditions. Heart-related lung problems.
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CT scan
This test uses a combination of X-rays and computer technology to produce horizontal, or axial, images (often called slices) of the body. CT scans are more detailed than regular X-rays.
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Blood tests
Arterial blood gas may be done to check the amount of carbon dioxide and oxygen in the blood. Other blood tests may be used to look for possible infections.
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Bronchoscopy
This is direct exam of the main airways of the lungs (bronchi) using a flexible tube called a bronchoscope. Bronchoscopy helps to evaluate and diagnose lung problems, check blockages, take out samples of tissue or
fluid, and help remove a foreign body. Bronchoscopy may include a biopsy or bronchoalveolar lavage.
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Bronchoalveolar lavage
Removing cells from the lower respiratory tract to help identify inflammation and exclude certain causes. During the procedure, a saline solution is put through the bronchoscope to wash the airways and capture a fluid sample
