THE HUMAN RESPIRATORY SYSTEM (PART 1: ASTHMA)

By Sir. Bright Boafoh

PRIMARY OBJECTIVES OF THIS LESSON

1. Identify and Describe Respiratory Anatomy:

Understand the structural components of the respiratory system, including the nose, trachea, bronchi, lungs, and alveoli. Describe the functions and characteristics of each part, including their role in ventilation and gas exchange.

2. Explain the Mechanisms of Breathing:

Explore the physiological processes involved in inhalation and exhalation. Describe the role of the diaphragm, intercostal muscles, and changes in thoracic volume and pressure during the breathing cycle.

3. Understand Gas Exchange and Transport:

Explore the mechanisms of oxygen and carbon dioxide exchange in the alveoli. Describe how gases are transported in the blood, including the role of hemoglobin in oxygen transport and the formation of bicarbonate ions for carbon dioxide transport.

4. Assess Respiratory Function:

Learn how to assess respiratory function in individuals, including measuring respiratory rate, depth, and pattern. Understand the significance of breath sounds, identify abnormal respiratory patterns, and interpret diagnostic tests such as spirometry.

5. Recognize Common Respiratory Disorders:

Identify and describe common respiratory disorders such as asthma, chronic obstructive pulmonary disease (COPD), pneumonia, and bronchitis. Understand the etiology, signs, symptoms, and management of these disorders, as well as their impact on respiratory function.

6. Apply Clinical Assessment Skills:

It will help you as a student to develop skills in assessing respiratory health, including the ability to measure respiratory rate, auscultate breath sounds, and recognize signs of respiratory distress.

7. Understand Developmental and Age-Related Changes:

Explore how the respiratory system evolves and undergoes changes throughout different life stages, from infancy to old age, including the impact on lung function.

Reasons why learning about the human respiratory system is crucial for nursing students:

1. Patient Assessment:

Understanding the respiratory system is fundamental for assessing patients’ health. Nursing students learn to evaluate respiratory rates, patterns, and breath sounds, which are vital indicators of a patient’s respiratory status. This knowledge is essential in identifying potential issues and implementing timely interventions.

2. Critical Care Management:

Respiratory complications often require critical care, and nurses play a crucial role in managing patients with conditions such as respiratory distress, pneumonia, or chronic obstructive pulmonary disease (COPD). Knowledge of the respiratory system is indispensable in administering appropriate treatments, monitoring vital signs, and assisting with respiratory therapies.

3. Medication Administration:

Many medications prescribed in healthcare, especially those targeting respiratory conditions, directly impact the respiratory system. Nursing students must comprehend the pharmacology of these medications, understand their effects on respiratory function, and be adept at administering them safely to patients.

4. Patient Education:

Nurses are educators who empower patients to manage their health effectively. Knowledge of the respiratory system allows nursing students to educate patients about preventive measures, lifestyle changes, and medication adherence to minimize the risk of respiratory issues and promote overall respiratory health.

5. Collaborative Care:

The respiratory system is interconnected with various other body systems, and respiratory conditions often require collaborative care. Nursing students learn to work in interdisciplinary teams, collaborating with respiratory therapists, physicians, and other healthcare professionals to provide comprehensive care for patients with respiratory disorders.

Definition

The human respiratory system is a complex network of organs and tissues that facilitates the exchange of gases between the body and the environment. Primary its either Oxygen, carbon dioxide and other gases.

The main body organs and tissues that form the human respiratory system

1. Nose
2. Nasal Cavity
3. Pharynx
4. Larynx
5. Trachea
6. Bronchi
7. Bronchioles
8. Lungs
9. Alveoli
10. Diaphragm

Importance of the respiratory system

Its primary function is to supply oxygen to the blood and remove carbon dioxide, a waste product, from the body.
Let us express them:

1. Oxygen Supply: The respiratory system is essential for supplying oxygen to the body’s cells, which is crucial for cellular respiration and the production of energy.

2. Carbon Dioxide Removal: It facilitates the removal of carbon dioxide, a waste product of cellular metabolism, preventing its accumulation and maintaining a balance in the bloodstream.

DIAGRAM OF HOW OXYGEN AND CARBONDIOXIDE ARE EXCHANGED IN HUMANS

3. Acid-Base Balance:

The respiratory system plays a role in regulating the body’s pH by controlling the levels of carbon dioxide and bicarbonate ions in the blood.
pH is a quantitative measure of the acidity or basicity of aqueous or other liquid solutions. It is a scale used to specify the acidity or basicity of an aqueous solution. The pH scale ranges from 0 to 14, with 7 being neutral. A pH greater than 7 means the substance is basic, while a pH less than 7 means the substance is acidic.
As carbondioxide levels increase, pH increases. Hence the blood is increasing in alkalinity.
As the carbondioxide levels decrease, pH increases resulting in more base in the blood.

4. Cellular Respiration:

Oxygen taken in through respiration is used in the process of cellular respiration, where glucose is broken down to produce energy (ATP) for cellular activities.

5. Metabolic Support:

It supports the metabolic processes of the body by providing the necessary oxygen for the breakdown of nutrients and the release of energy.

6. Detoxification:

The respiratory system aids in detoxifying the body by expelling gaseous waste products, such as volatile organic compounds (VOCs) from the bloodstream through exhalation. Examples of VOC includes, acetone, ethene, isoprene, ethanol from alcohol etc.

7. Immune Defense:

The respiratory tract’s mucus and cilia help trap and remove pathogens and particles, contributing to the body’s immune defense against infections.

8. Temperature Regulation:

Breathing influences heat exchange in the body, contributing to temperature regulation by releasing excess heat during exhalation.

9. Voice Production:

The larynx and vocal cords in the respiratory system play a crucial role in voice production and communication.

10. Integration with Circulatory System:

It works in conjunction with the circulatory system, ensuring the efficient transport of oxygenated blood to body tissues and the removal of deoxygenated blood from the tissues.

Key components of the respiratory system

1. Nose and Nasal Cavity:

The nose is the primary entrance for air into the respiratory system.
Hairs and mucous membranes in the nasal cavity help filter, warm, and moisten the incoming air.

2. Pharynx (Throat):

The pharynx serves as a common pathway for both air and food.
It is divided into three parts: nasopharynx, oropharynx, and laryngopharynx.

A. Nasopharynx: The nasopharynx is the upper part of the pharynx (throat) that lies behind the nose and above the soft palate. It serves as a passageway for air from the nasal cavity to the rest of the respiratory system.

B. Oropharynx: The oropharynx is the middle part of the pharynx located behind the mouth. It serves as a common pathway for both air and food, playing a role in both the respiratory and digestive systems.

C. Laryngopharynx: The laryngopharynx is the lower part of the pharynx that extends from the level of the epiglottis to the esophagus. It serves as a passage for both air and food, directing air into the trachea and food into the esophagus.

3. Larynx (Voice Box):

The larynx contains vocal cords that vibrate to produce sound when air passes through.

4. Trachea (Windpipe):

The trachea is a tube that connects the larynx to the bronchi.
It is reinforced with cartilage rings to prevent collapse.

DIAGRAM OF THE HUMAN LARYNX & TRACHEA

5. Lungs:

The lungs are the main organs of respiration.
Each lung is divided into lobes and is surrounded by a protective membrane called the pleura.

6. Bronchi and Bronchioles:

The trachea branches into two bronchi, which further divide into smaller bronchioles.
Bronchioles lead to tiny air sacs called alveoli.

7. Alveoli:

Alveoli are tiny air sacs where the exchange of oxygen and carbon dioxide takes place.
Oxygen from the air diffuses into the bloodstream, while carbon dioxide moves from the blood to the alveoli to be exhaled.

8. Diaphragm:

The diaphragm is a muscular sheet that separates the chest cavity from the abdominal cavity.
Contraction and relaxation of the diaphragm control breathing by changing the volume of the chest cavity.
The process of respiration involves two main phases:

A. Inhalation (Inspiration):

The diaphragm contracts, and the chest cavity expands.
This creates a negative pressure, drawing air into the lungs.

B. Exhalation (Expiration):

The diaphragm relaxes, and the chest cavity decreases in volume.
This creates a positive pressure, forcing air out of the lungs.

9. Pulmonary Blood Vessels:

Pulmonary arteries carry deoxygenated blood from the heart to the lungs.
In the alveoli, carbon dioxide is exchanged for oxygen, and oxygenated blood returns to the heart through pulmonary veins.

10. Cilia and Mucus:

The respiratory tract is lined with cilia (hair-like structures) and mucus, helping to trap and remove particles and pathogens, preventing them from reaching the lungs.

Functions of Nose, Nasal Cavity, and Pharynx

1. Nose and Nasal Cavity:
Air Filtration: Traps dust, particles, and pathogens.
Moistening and Warming: Produces mucus to optimize air temperature and humidity.
Olfaction: Enables the sense of smell through olfactory receptors.
Resonance: Contributes to voice resonance during speech.
Nasal Reflexes: Triggers reflex actions, like sneezing, to expel irritants.

2. Pharynx:
Connection to Trachea: Serves as a passageway for air and food, connecting nasal and oral cavities to the trachea and esophagus.
Epiglottis Protection: Guards the trachea during swallowing, directing food to the esophagus.
Speech Production: Modulates vocal cord sounds, acting as a resonating chamber.
Tonsil Location: Immune-related tonsils defend against pathogens.

Mechanics of Breathing (How breathing occurs in humans)
The mechanics of breathing follow Boyle’s Law which states that pressure and volume have an inverse relationship.

Inhalation (Inspiration):

During inhalation, the diaphragm, a muscular sheet below the lungs, contracts and moves downward.
Simultaneously, the intercostal muscles between the ribs contract, causing the ribcage to expand.
The expansion of the chest cavity lowers air pressure in the lungs, allowing air from the environment to rush in through the nose or mouth.
Oxygen-rich air enters the respiratory system and moves into the lungs.

Exhalation (Expiration):

During exhalation, the diaphragm relaxes, moving back upward, and the intercostal muscles relax.
The chest cavity decreases in size, increasing air pressure in the lungs.
This elevated pressure forces air, now rich in carbon dioxide, out of the lungs through the nose or mouth.
The process of inhalation and exhalation repeats, maintaining a continuous exchange of gases to support cellular respiration.

Inspiration: Inhaling air into lungs.
Expiration: Exhaling air from lungs.
Active muscle contraction during inspiration; passive relaxation during expiration.

Respiratory Controls

Respiratory control refers to the physiological mechanisms and processes that regulate the rate and depth of breathing to maintain appropriate levels of oxygen (O2) and carbon dioxide (CO2) in the body. The respiratory control system operates through a feedback loop that involves the respiratory centers in the brain, peripheral chemoreceptors, and various sensors in the respiratory and circulatory systems.

Key components of respiratory control include:

1. Respiratory Centers:

The primary respiratory centers are located in the brainstem, specifically the medulla oblongata and the pons. The medullary respiratory center contains the dorsal respiratory group (DRG) and ventral respiratory group (VRG), while the pontine respiratory group (PRG) is found in the pons. These centers generate rhythmic signals that control the muscles involved in breathing.

2. Peripheral Chemoreceptors:

Chemoreceptors are sensors that detect changes in the levels of oxygen, carbon dioxide, and pH in the blood. The carotid bodies and aortic bodies are examples of peripheral chemoreceptors located in the carotid arteries and aorta, respectively. These receptors play a crucial role in responding to alterations in blood gas concentrations.

3. Central Chemoreceptors:

Found in the medulla oblongata, central chemoreceptors are sensitive to changes in the pH of the cerebrospinal fluid. They indirectly sense carbon dioxide levels, as an increase in CO2 leads to the formation of carbonic acid, resulting in a decrease in pH.

4. Stretch Receptors:

Stretch receptors, located in the lungs and airways, monitor the degree of lung expansion. They provide feedback to the respiratory centers, helping regulate the duration of inhalation and exhalation to prevent overinflation or collapse of the lungs.

5. Neural and Hormonal Influences:

Neural signals from higher brain centers, such as those involved in emotions and stress responses, can influence respiratory control. Additionally, hormones such as adrenaline can impact respiratory rate and depth.

Common Respiratory Disorders

There are several common respiratory disorders that can affect humans, ranging from mild, temporary conditions to chronic and potentially severe diseases. Here are some of the most prevalent respiratory disorders: Asthma, Chronic Obstructive Pulmonary Disease (COPD), Pneumonia, Bronchitis, Influenza (Flu), Interstitial Lung Disease (ILD), Sleep Apnea, Cystic Fibrosis, Lung Cancer, Tuberculosis (TB)

1. Asthma:

Asthma is a chronic condition characterized by inflammation and narrowing of the airways, making it difficult to breathe. It’s noncommunicable disease. That means the condition cannot be passed from person to person. Noncommunicable diseases are often chronic and result from a combination of genetic, environmental, and lifestyle factors.
This inflammation is characterized by wheezing, coughing, and shortness of breath. Asthma often has triggers, such as allergens or irritants, and can vary in severity.

Susceptibility of Asthma

Asthma is more likely if other family members also have asthma – particularly a close relative, such as a parent or sibling. In general, anyone can get asthma.

Signs and symptoms of Asthma

Symptoms are often worse at night or during exercise.
Common symptoms of asthma include:
1. A persistent cough, especially at night
2. Wheezing when exhaling and sometimes when inhaling
3. Shortness of breath or difficulty breathing, sometimes even when resting
4. Chest tightness, making it difficult to breathe deeply.

Causes of Asthma

The causes of asthma are complex and can involve a combination of genetic, environmental, and lifestyle factors. Before that, know that:
Bronchospasm: The muscles around the airways constrict (tighten). When they tighten, it makes your airways narrow. Air cannot flow freely through constricted airways.
Inflammation: The lining of your airways becomes swollen. Swollen airways don’t let as much air in or out of your lungs.
Mucus production: During the attack, your body creates more mucus. This thick mucus clogs airways.

1. Genetic Factors:
Family history of asthma or allergic conditions can increase the likelihood of developing asthma.

2. Environmental Allergens:
Exposure to allergens such as pollen, mold, pet dander, and dust mites can trigger asthma symptoms.

3. Tobacco Smoke:
Both active smoking and exposure to secondhand smoke can increase the risk of asthma, especially in children.

4. Occupational Exposures:
Exposure to certain workplace irritants or allergens, such as chemicals, dust, or fumes, can contribute to the development of asthma.

5. Respiratory Infections:
Viral respiratory infections, particularly during early childhood, can increase the risk of developing asthma.

6. Physical Activity and Exercise:
Intense physical activity or exercise, especially in cold or dry air, can trigger asthma symptoms in some individuals.

7. Air Pollution:
Exposure to outdoor air pollutants, such as particulate matter and ozone, can worsen asthma symptoms and contribute to the development of the condition.

Types of Asthma

The types are based on the cause and the severity of symptoms.

1. Intermittent Asthma:
Symptoms occur less than twice a week.
Nighttime symptoms occur less than twice a month.
Lung function (measured by spirometry) is normal between exacerbations.

2. Mild Persistent Asthma:
Symptoms occur more than twice a week but less than once a day.
Nighttime symptoms occur more than twice a month.
Lung function may show a slight reduction.

3. Moderate Persistent Asthma:
Daily symptoms are present.
Nighttime symptoms occur more than once a week.
Lung function shows noticeable reductions.

4. Severe Persistent Asthma:
Continuous symptoms throughout the day.
Frequent nighttime symptoms.
Lung function significantly impaired.

Diagnostic tests for Asthma: How do we diagnose asthma?

As a nurse, before you can diagnose asthma, you need to first review the patient’s medical and family history, and then about his/her current symptoms.
After that you need to confirm your diagnosis by carrying out any of the below tests.

1. Spirometry:

Purpose: Measures how much air you can inhale and exhale and how quickly you can do it.
Procedure: The person takes a deep breath and then exhales forcefully into a tube connected to a spirometer.
Results: Provides information on lung function, including forced vital capacity (FVC) and forced expiratory volume in one second (FEV1).

2. Chest X-ray or CT Scan:

Purpose: Rules out other respiratory conditions that may mimic asthma symptoms.
Procedure: X-ray or CT images of the chest are taken.
Results: Helps identify abnormalities in the lungs or chest.

3. Allergy Testing:

Purpose: Identifies specific allergens that may trigger asthma symptoms.
Procedure: Skin prick tests or blood tests are performed to detect allergic sensitivities.
Results: Guides the development of an allergy management plan.

4. Peak Expiratory Flow (PEF) Measurement:

Purpose: Measures the maximum speed of exhalation.
Procedure: The person blows forcefully into a handheld device called a peak flow meter.
Results: Helps assess the degree of airway obstruction and monitor changes in airflow.

Management and Treatment. How do we manage or treat Asthma?

We can manage and treat asthma with both pharmacological or non-pharmacological means. But note that in general, asthma can not be cured.

A. Pharmacological Management

The pharmacological management of asthma involves a combination of medications to control symptoms, preventing complications and improving overall lung function.

1. Inhaled Corticosteroids
Purpose: Reduce airway inflammation.
Examples: Fluticasone(Flovent), budesonide(Rhinocort, Entocort), beclomethasone(Beconase AQ).
Usage: Long-term control, especially in persistent asthma.

2. Oral Corticosteroids:

Purpose: Provide anti-inflammatory effects for severe exacerbations.
Examples: Prednisone, methylprednisolone.
Usage: Short courses during acute exacerbations, not for long-term use.

3. Long-Acting Beta-Agonists

Purpose: Relax smooth muscles in the airways, promoting bronchodilation. A bronchodilator or broncholytic is a substance that dilates the bronchi and bronchioles, decreasing resistance in the respiratory airway and increasing airflow to the lungs.
Examples: Salmeterol, formoterol.
Usage: Combined with inhaled corticosteroids for long-term control. It should not be used as monotherapy.

4. Short-Acting Beta-Agonists

Purpose: Provide rapid relief of acute bronchoconstriction.
Examples: Albuterol, levalbuterol.
Usage: Quick-relief or rescue medication during acute symptoms.

B. Non-pharmacological Management of asthma

Non-pharmacological management of asthma involves strategies and lifestyle modifications to help control symptoms and improve overall well-being.

1. Education:

Comprehensive patient education is crucial. Individuals with asthma should understand their condition, triggers, and the proper use of medications and devices.

2. Trigger Avoidance:

Identify and minimize exposure to environmental triggers such as allergens, smoke, pollutants, and occupational irritants.

3. Allergen Control:

Implement measures to reduce exposure to common allergens, such as using mattress and pillow covers, regular cleaning, and maintaining a hypoallergenic living environment.

4. Smoking Cessation:

Encourage individuals with asthma who smoke to quit and promote a smoke-free environment to reduce exposure to secondhand smoke.

5. Physical Activity and Exercise:

Encourage regular physical activity tailored to the individual’s capabilities. Ensure proper warm-up and cool-down to minimize exercise-induced bronchoconstriction.

6. Weight Management:

Address and support weight management strategies when applicable, as obesity can contribute to asthma severity.

7. Stress Management:

Stress can trigger asthma symptoms in some individuals. Implement stress-reduction techniques, such as mindfulness, relaxation exercises, or counseling.

What are the Nursing and Emergency interventions for asthmatic episode?

Nebulizer with Petri mask

Asthma Inhaler

During an asthmatic episode, emergency interventions aim to quickly relieve symptoms and improve airflow.

1. Use a quick-relief inhaler or nebulizer (usually containing a short-acting bronchodilator, such as albuterol) to open up the airways. Albuterol is the same as Salbutamol.

2. Encourage the person to stay calm, sit upright, and avoid lying down. This position can facilitate easier breathing.

3. Loosen any tight clothing around the neck and chest to reduce restriction and make breathing easier.

4. Encourage slow, deep breaths to help control hyperventilation and promote relaxation.

5. If the patient’s condition is severe, oxygen therapy may be provided to ensure adequate oxygen levels in the blood.

How do we use the salbutamol with the nebulizer?

Salbutamol respirator solution 5 mg/ml – for use with nebulizer:
A nebulizer is a device that turns liquid(medication) into a fine mist which you breathe in through a face mask or a mouthpiece.

Take care not to let the mist from the nebulizer get in your eyes.
Use your nebulizer in a well-ventilated room as some of the mist will be released into the air and may be breathed in by others.

1. To use salbutamol nebulizer solution:
2. Prepare the nebulizer for filling
3. Measure out the prescribed amount of respirator solution and put it in the nebulizer bowl
4. Add the right amount of sterile normal saline solution (make sure your doctor has told you how much to use), thats if it a tablet
5. Put the top on the nebulizer bowl and shake it gently to mix the contents
6. Assemble the nebulizer and use it on patient.
7. Place the mouthpiece in your mouth and make a seal by closing your lips around it. This will ensure that the medication goes into your lungs instead of leaking out the sides of your mouth. Masks that cover the nose and mouth are available for babies and young children who may find it difficult to keep a good seal.
8. Begin breathing through your mouth, taking natural, even breaths. You breathe in and out through the mouthpiece.
9. Sit upright during the treatment and keep the medication cup upright to ensure complete medication delivery. Pediatric masks may allow children to lie down during the treatment. Your doctor may tell you to take deep breaths occasionally or to hold your breath during the treatment briefly.
10. The treatment should take about 10-15minutes until the medication cup is empty and the mist stops.
11. Turn off the machine and remove the medication cup and mouthpiece.
12. After use throw away any solution remaining in the nebulizer bowl.
13. Clean your nebulizer in the recommended way

What are the Age-related changes and impact on asthma management?

Children consideration
Young children may have difficulty expressing their symptoms, requiring careful observation by parents and healthcare providers.

Adult consideration
Asthma in adults may coexist with other chronic conditions, such as cardiovascular disease or diabetes, requiring a comprehensive approach to healthcare.
Smoking, occupational exposures, and lifestyle choices become more significant factors in adult asthma management.

Aged consideration
Some aged may have reduced Lung Function. The declining in lung function may affect the presentation and management of asthma symptoms.
Older adults may be on multiple medications for various health conditions, and nurses have to consider potential drug interactions and adherence to asthma medications.