Respiratory System

Notes

Overview

Cells in the body require oxygen to survive. Vital functions of the body are carried out as the body is continuously supplied with oxygen. Without the respiratory system exchange of gases in the alveoli will not be made possible and systemic distribution of oxygen will not be made possible. The transportation of oxygen in the different parts of the body is accomplished by the blood of the cardiovascular system. However, it is the respiratory system that carries in oxygen to the body and transports oxygen from the tissue cells to the blood. Thus, cardiovascular system and respiratory system works hand in hand with each other. A problem in the cardiovascular system would affect the other and vice versa.

Respiratory System

Functional Anatomy of the Respiratory System
Nose

The nose is the only external part of the respiratory system and is the part where the air passes through. During inhalation and exhalation, air enters the nose by passing through the external nares or nostrils. Nasal cavity is found inside the nose and is divided by a nasal septum. The receptors for the sense of smell, olfactory receptors are found in the mucosa of the slit-like superior part of the nasal cavity which is located beneath the ethmoid bone. Respiratory mucosa lines the rest of the nasal cavity and rests on a rich network of thin-walled veins that warms the air passing by.

Important information about nose is the presence of the sticky mucus that is produced by the mucosa’s gland. This important characteristic moistens the air and traps the incoming bacteria and other foreign debris passing through the nasal cavity. Cells of the nasal mucosa are ciliated and it creates a gentle current that moves the contaminated mucus posteriorly towards the throat, where it is swallowed and digested by stomach juices.

In cases where the temperature of the environment is cold, the cilia become sluggish. Thus, more mucus are allowed to accumulate in the nasal cavity and to dribble outward through the nostrils. This is the main reason why a “runny nose” is noted during a cold day.

Conchae – these are three mucosa-covered projections or lobes that greatly increase the surface area of the mucosa exposed to the air.  Aside from that, conchae increase the air turbulence in the nasal cavity.

Palate – a partition that separates the nasal cavity from the oral cavity.  Anteriorly, the palate that is supported by a bone called the hard palate and the one which is unsupported is the soft palate.

Paranasal Sinuses – these are structures surrounding the casal cavity and are located in the frontal, sphenoid, ethmoid and maxillary bones.

Pharynx

The pharynx is a 13 cm long muscular tube that is commonly called the throat. This muscular passageway serves as a common food and air pathway. This structure is continuous with the nasal cavity anteriorly via the internal nares.

Parts of pharynx:

  1. Nasopharynx – the superior portion of the pharynx. The pharyngotympanic tubes that drain the middle ear open in this area. This is the main reason why children who have otitis media may follow a sore throat or other tyoes of pharyngeal infections since the two mucosae of these regions are continuous.
  2. Oropharynx – middle part
  3. Laryngopharynx – part of pharynx that enters the larynx.

When food enters the oral cavity, it travels to the oropharynx and laryngopharynx. However, instead of entering the larynx, the food is directed into the esophagus and not to the larynx.

Tonsils – clusters of lymphatic tissues found in the pharynx.

Types of Tonsils:

  1. Palatine tonsils – tonsils found at the end of the soft palate.
  2. Pharyngeal tonsils – lymphatic tissues located high in the nasopharynx. This is also called adenoid.
  3. Lingual tonsils – located at the base of the tongue.
Larynx

The larynx is the one that routes the air and food into their proper channels. Also termed as the voice box, it plays an important role in speech. This structure is located inferior to the pharynx and is formed by:

  1. Eight rigid hyaline cartilages
  2. Spoon-shaped flap of elastic cartilage, which is called the epiglottis.

Thyroid cartilage – this is the largest hyaline cartilage that protrudes anteriorly in males and is referred to as the Adam’s apple.

Epiglottis – this is a flap of tissue that serves as a guardian of the airways as it protects the superior portion of the larynx. The epiglottis does not restrict passage of air into the lower respiratory passages when a person is not swallowing. However, when a person swallows food, the epiglottis tips and forms a lid or blocks the opening of the larynx so that food will not be directed to the lower respiratory passages. The food will be then routed to the esophagus and in cases where it enters the larynx, a cough reflex is triggered to expel the substance and prevent it from continuing into the lungs. This protective reflex does not work when a person is unconscious that is why it is not allowed to offer or administer fluids to an unconscious client.

Vocal folds – a pair of folds which is also called the true vocal cords that vibrate when air is expelled.

Glottis – the slit-like passageway between the vocal folds.

Trachea

Also called the windpipe, the trachea is about 10 to 12 cm long or about 4 incheas and travels dwon from the larynx to the fifth thoracic vertebra. This structure is reinforced with C-shaped rings of hyaline cartilage and these rings are very important for the following purposes:

  1. The open parts of the rings abut the esophagus that allows the structure to expand anteriorly when a person swallows a large size of food.
  2. The solid portions of the C-rings are supporting the walls of the trachea to keep it patent or open even though pressure changes during breathing.

The trachea is lined with ciliated mucosa that primarily serves for this purpose: To propel mucus loaded with dust particles and other debris away from the lungs towards the throat where it can either be swallowed or spat out.

Main Bronchi

The main bronchi, both the right and the left, are both formed by tracheal divisions. There is a slight difference between the right and left main bronchi. The right one is wider, shorter and straighter than the left. This is the most common site for an inhaled foreign object to become lodged. When air reaches the bronchi, it is already warmed, cleansed of most impurities and well humidified.

Lungs

The lungs are fairly large organs that occupy the most of the thoracic cavity. The most central part of the thoracic cavity, the mediastinum, is not occupied by the lungs as this area houses the heart.

Apex – the narrow superior portion of each lung and is located just below the clavicle

Base – the resting area of the lung. This is a broad lung area that rests on the diaphragm.

Divisions of the Lungs

The lungs are divided into lobes by the presence of fissures. The left lung has two lobes while the right lung has three.

Pleural Layers

Visceral pleura – also termed as the pulmonary pleura and covers each surface of the lings.

Parietal pleura – covers the walls of the thoracic cavity.

Pleural fluid – a slippery serous secretion that allows the lungs to slide along over the thorax wall during breathing movements and causes the two pleural layers to cling together.

Bronchioles – smallest air-conducting passageways.

Bronchial tree or respiratory tree – a network formed due to the branching and rebranching of the respiratory passageways within the lungs.

Alveoli – air sacs. This is the only area where exchange of gases takes place. Millions of clustered alveoli resembles bunches of grapes and these structures make up the bulk of the lungs.

Respiratory Zone – this part includes the respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli.

Physiology of Respiration

The respiratory primarily supplies oxygen to the body and disposes of carbon dioxide through exhalation. Four events chronologically occur, for respiration to take place.

  1. Pulmonary ventilation – this process is commonly termed as breathing. With pulmonary ventilation, air must move out into and out of the lungs so that the alveoli of the lungs are continuously drained and filled with air.
  2. External respiration – this is the exchange of gases or the loading of oxygen and the unloading of carbon dioxide between the pulmonary blood and alveoli.
  3. Respiratory gas transport – this is the process where the oxygen and carbon dioxide is transported to the and from the lungs and tissue cells of the body through the bloodstream.
  4. Internal respiration – in internal respiration the exchange of gases is taking place between the blood and tissue cells.
Mechanics of Breathing

Breathing, also called pulmonary ventilation is a mechanical process that completely depends on the volume changes occurring in the thoracic cavity. Thus, a when volume changes pressure also changes, and this would lead to the flow of gases equalizing with the pressure.

Inspiration – also called inhalation. This is the act of allowing air to enter the body. Air is flowing into the lungs with this process. Inspiratory muscles are involved with inspiration which includes:

  1. The diaphragm
  2. External intercostals

These muscles contract when air is flowing in and thoracic cavity increases. When the diaphragm contracts it slides inferiorly and is depressed. As a result the thoracic cavity increases. The contraction of the external intercostal muscles lifts the rib cage and thrusts the sternum forward. This increases the anteroposterior and lateral dimensions of the thorax.

Expiration – also called expiration. It the process of breathing out air as it leaves the lungs. This process causes the gases to flow out to equalize the pressure inside and outside the lungs. Under normal circumstances, the process of expiration is effortless.

Exam

Welcome to your MSN Exam for Respiratory System! This exam is carefully curated to help you consolidate your knowledge and gain deeper understanding on the topic.

 

Exam Details

  • Number of Questions: 20 items
  • Mode: Practice Mode

Exam Instructions

  1. Practice Mode: This mode aims to facilitate effective learning and review.
  2. Instant Feedback: After each question, the correct answer along with an explanation will be revealed. This is to help you understand the reasoning behind the correct answer, helping to reinforce your learning.
  3. Time Limit: There is no time limit for this exam. Take your time to understand each question and the corresponding choices.

Tips For Success

  • Read each question carefully. Take your time and don't rush.
  • Understand the rationale behind each answer. This will not only help you during this exam, but also assist in reinforcing your learning.
  • Don't be discouraged by incorrect answers. Use them as an opportunity to learn and improve.
  • Take breaks if you need them. It's not a race, and your understanding is what's most important.
  • Keep a positive attitude and believe in your ability to succeed.

Remember, this exam is not just a test of your knowledge, but also an opportunity to enhance your understanding and skills. Enjoy the learning journey!

 

Click 'Start Exam' when you're ready to begin. Best of luck!

💡 Hint

In our bodies, there's a delicate balance of acids and bases, often referred to as our body's pH. The lungs and kidneys play pivotal roles in this system, each addressing a unique aspect - respiratory and metabolic. This balance is crucial, as too much or too little of either can lead to health problems. Therefore, understanding the relationship between pH, HCO3, BE, and pCO2 is vital to diagnosing a variety of medical conditions. Keep in mind how our respiratory system can influence this balance.

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1. If we consider the given medical parameters - increased pH, typical bicarbonate levels (HCO3), ordinary base excess (BE), and decreased partial pressure of carbon dioxide (pCO2), to which of these physiological states does this constellation of factors most likely correspond?

💡 Hint

As we've seen before, our bodies function optimally when there's a balance of acids and bases. The kidney is one major player in maintaining this balance, especially when it comes to controlling bicarbonate (HCO3) levels and base excess (BE). Changes in these factors, along with shifts in our pH, can signify metabolic disruptions. Now, remember that 'metabolic' implies a broader set of biological processes than 'respiratory'. Could this hint help you solve the puzzle?

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2. Given these physiological observations:

  • Elevated pH levels
  • Increased bicarbonate (HCO3) concentration
  • High base excess (BE)
  • Normal levels of partial pressure of carbon dioxide (pCO2)

Which condition is most likely to be associated with this combination of indicators?

💡 Hint

The complex architecture of our lungs, right down to the microscopic level, is indeed awe-inspiring. Tiny air sacs called alveoli are at the heart of our respiratory system, where gas exchange happens. These alveoli contain specialized cells that carry out unique functions, all designed to ensure that every breath we take brings life-giving oxygen into our bodies and expels waste carbon dioxide. One of these functions involves a slippery substance that plays a vital role in keeping the delicate alveoli from collapsing. This is like a safety net, spread by a specific type of cell. But, which one could that be?

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3. Among the following cellular entities, which is responsible for the production and secretion of surfactant?

💡 Hint

In respiratory conditions where mucus buildup becomes problematic, mucolytics play an important role. These drugs break down the mucus, making it less sticky and easier to expel, which helps clear the airways and improve breathing. Imagine a glue dissolver working its way through a clogged pipe. It's similar to that! Now, can you identify the medication that works in such a way from the provided list?

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4. Among the medications listed, which one is classified as a mucolytic, a drug that breaks down mucus to help clear the airways?

💡 Hint

Consider this: you might typically hear the sound associated with this phenomenon when listening to a patient with asthma during a stethoscope examination.

5 / 20

5. Can you identify the term from the list of pulmonary concepts that corresponds to the phenomenon of bronchial wall spasms?

💡 Hint

Respiratory conditions often come with the challenge of mucus buildup in the airways, leading to coughing and breathing difficulties. To manage these symptoms, certain medications called expectorants are employed. These drugs work by thinning and loosening the mucus in the airways, making it easier to cough up. That way, they help clear the lungs and make breathing easier. Some might be more familiar as ingredients in over-the-counter cough medicines. Can you guess which of these drugs works in that way?

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6. Out of the following medications, which one is recognized as an expectorant, aiding in the expulsion of mucus from the lungs?

💡 Hint

As we delve deeper into the human body's extraordinary balancing act of acids and bases, we see how this balance is influenced by both our lungs (respiratory) and kidneys (metabolic). This intricate dance of ions, including bicarbonate (HCO3) and base excess (BE), can be impacted by various factors, causing imbalances that may lead to health conditions. To help you identify the right answer, consider how a decrease in pH might manifest itself. Is it more likely to be 'acidic' or 'alkaline'? And remember, 'metabolic' factors might have a broader scope than just 'respiratory'. Does that help you narrow it down?

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7. Reflecting on the subsequent biological indicators:

  • Reduced pH levels
  • Diminished bicarbonate (HCO3) concentration
  • Low base excess (BE)
  • Normal levels of partial pressure of carbon dioxide (pCO2)

Which physiological state could be connected with this specific set of attributes?

💡 Hint

Each term in the medical field carries a very specific meaning, which often helps physicians make accurate diagnoses. When it comes to lung sounds, these terms can even describe the sound made when air moves through narrowed or obstructed respiratory passages. Imagine a musical instrument - when the passage of air is obstructed, the sound produced can become high-pitched and musical. This can provide a vital clue for doctors when diagnosing specific respiratory conditions. Which term best fits this description?

8 / 20

8. Looking at the following respiratory terminologies, which term corresponds with the observation of blockage in the trachea or larynx?

💡 Hint

In the world of respiratory medicine, bronchodilators play a crucial role. They're medications designed to open up (dilate) the bronchial tubes, allowing more air to flow through and making breathing easier for individuals with conditions like asthma or COPD. These drugs can be quite diverse, but they all have this shared function. Just like a door can open wider to let more people through, bronchodilators 'open' the airways to allow more air in and out. So, which one of these medicines does that job?

9 / 20

9. From the following list of medications, which one is recognized as a bronchodilator, designed to widen the bronchi and bronchioles to facilitate breathing?

💡 Hint

This term is about the extra breath you can take in, above and beyond the average breath, after a typical exhalation.

10 / 20

10. Among the following respiratory terms, which one fits the description: The quantity of air that can be drawn in after the expiration of a normal tidal volume?

💡 Hint

Our bodies are pretty remarkable when it comes to maintaining balance, aren't they? Bicarbonate is one such substance that plays a significant role in maintaining the pH balance in our blood and other bodily fluids. However, this balance is precise, and too much or too little of it can upset the equilibrium, which can lead to medical problems. Remember, like in any healthy equilibrium, there's a 'goldilocks' zone - not too low, not too high, but just right.

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11. If we look at the commonly accepted normal range for bicarbonate (HCO3) in the human body, how is this typically expressed in milliequivalents per liter (mEq/L)?

💡 Hint

Chronic Obstructive Pulmonary Disease, or COPD, is a broad term encompassing a number of lung diseases, each having unique but overlapping characteristics. These conditions primarily involve breathing difficulties due to various changes in the bronchial tubes and lung tissue. Yet, not all bronchial or pulmonary conditions fall under the COPD umbrella. Sometimes, a term might seem related because of its 'bronchial' prefix, but may be referring to a different type of condition altogether. So, which of these conditions do you think might be the odd one out?

12 / 20

12. Among the following conditions, which one is not typically associated with Chronic Obstructive Pulmonary Disease (COPD)?

💡 Hint

Chronic Obstructive Pulmonary Disease, commonly known as COPD, is a chronic inflammatory lung disease that obstructs airflow from the lungs. It can lead to a number of serious complications, particularly ones that involve the heart and lungs due to the increased effort needed to breathe. While COPD may indirectly lead to certain systemic symptoms, not all conditions mentioned here are typically a direct consequence of COPD. Is there one that seems less likely to be tied directly to this chronic lung condition?

13 / 20

13. Among the following health issues, which one is not typically a result of Chronic Obstructive Pulmonary Disease (COPD)?

💡 Hint

Tuberculosis remains one of the most infectious diseases worldwide, with its detection and control being of paramount importance. The Tuberculin Skin Test is one such tool used for detection. The test measures the body's immune response to the bacteria causing TB. A 'reaction' is seen as a raised, hard area or 'induration' on the skin where the test was done. Interestingly, the size of this induration is crucial in determining the test results. Imagine how important a tiny difference in millimeters could be in making a diagnosis!

14 / 20

14. Given the following criteria, which most accurately represents a negative reaction to the Tuberculin Skin Test (TST) for tuberculosis (TB)?

💡 Hint

Xanthines are a group of alkaloids commonly used for their effects as mild stimulants and as bronchodilators, mostly in treating symptoms of asthma and COPD. These compounds work on a cellular level, influencing a variety of physiological processes. It's interesting to know that naturally occurring xanthines include caffeine, found in coffee and tea. Now, among the listed drugs, which one do you think belongs to this fascinating class of compounds?

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15. Out of the provided list of drugs, which one belongs to the class of compounds known as xanthines?

💡 Hint

Remember, the term you're looking for is often used to assess a person's overall lung health, as it involves both the maximum inhalation and the maximum exhalation a person can achieve.

16 / 20

16. Considering the following respiratory terms, which one aligns with the definition: The maximum amount of air that can be forcefully expelled after taking the deepest possible inhalation?

💡 Hint

Our body's respiratory system works tirelessly to maintain a stable environment for our cells. One critical aspect of this is regulating the levels of carbon dioxide (pCO2), a waste product of cellular respiration. These levels are monitored and maintained within a relatively narrow range to ensure our bodies function optimally. To give you a perspective, think about the concept of 'tipping point'. It's the sweet spot where things are in balance. Too much or too little beyond this 'tipping point' can disrupt the equilibrium, which could potentially lead to health issues.

17 / 20

17. When referring to standard measurements of partial pressure of carbon dioxide (pCO2) in the human body, what is the range typically expressed in millimeters of mercury (mmHg)?

💡 Hint

Infectious diseases can be caused by a wide variety of organisms, including bacteria, viruses, parasites, and fungi. When it comes to treating fungal infections like Pneumocystis carinii, a certain group of medications is frequently employed. These drugs typically target the unique structures or biological processes of the fungal cells, effectively combating the infection. Now, given these clues, can you identify which medication in the list might be the antifungal warrior?

18 / 20

18. Among the given medications, which one is typically used to combat infections caused by Pneumocystis carinii, a type of fungus?

💡 Hint

It's truly marvelous how our bodies function, isn't it? Breathing, an essential process, is mostly automatic, regulated by specific areas in our brain. These regions receive and send signals to our respiratory muscles, adjusting our breathing rate and depth according to our body's needs. If you're looking for a clue, consider the different parts of the brain and their functions. The 'primitive' parts of our brain are often in charge of our most basic and critical functions. Which two parts might be working together to keep us breathing?

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19. The vital control center that manages our breathing patterns is situated within which two sections of the brain?

💡 Hint

While contemplating your answer, you might find it helpful to know that this type of lung cancer often arises from the cells that line the lungs' smallest airways, the bronchioles and alveoli.

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20. Out of the following varieties, which form of lung cancer is most frequently diagnosed?