3.5 Chapter 10 Levitsky

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Questions and Answers

What function does the upper airways serve in relation to the inspired air?

Air-conditioning function (correct)

Metabolic functions

Filtration and removal of particles

Reservoir of biologically active materials

What is one of the metabolic functions of the lung described in the text?

Handling of vasoactive materials in the blood (correct)

Reservoir of biologically active materials

Protection from contaminants in inspired air

Filtration and removal of particles

Which of the following is an example of a hazardous material that may be present in inspired air?

Oxygen

Bacteria (correct)

Carbon dioxide

Nitrogen

What is one of the mechanisms by which the lung is protected from contaminants in inspired air?

Filtration and removal of particles Signup and view all the answers

What allows the lungs to act as a site of blood filtration and storage?

The pulmonary circulation's high compliance Signup and view all the answers

Why can the pulmonary circulation act as a reservoir for the left ventricle?

High compliance and negative intrapleural pressure Signup and view all the answers

What role does the pulmonary circulation play in protecting the systemic circulation?

Acts as a filter Signup and view all the answers

Which of the following is NOT a potential particle that may be filtered by the pulmonary circulation?

Oxygen molecules Signup and view all the answers

How does the lung prevent occlusion of vascular beds by filtered particles?

Lytic enzymes in vascular endothelium Signup and view all the answers

What is the function of the nasal turbinates in relation to inspired air?

To humidify the air Signup and view all the answers

How do most particles larger than 10 μm get filtered in the respiratory tract?

By impaction in the nasal hairs Signup and view all the answers

Where do smaller particles between 0.1 and 0.5 μm mainly get deposited in the respiratory system?

Exhaled as aerosols Signup and view all the answers

What stimulates a cough in the respiratory tract?

Stimulation of receptors in the trachea Signup and view all the answers

Where is the primary impaction site for larger particles in the respiratory tract?

Posterior wall of the pharynx Signup and view all the answers

What causes most particles between 2 to 10 μm to be removed from the airways?

Brownian motion Signup and view all the answers

Which structure is mainly responsible for the production of airway secretions?

Goblet cells Signup and view all the answers

What is the term used for the synchronized movement of mucus up the airway carried out by cilia?

Mucociliary transport Signup and view all the answers

Which condition may result in an increase in goblet cells and hypertrophy of mucous glands, leading to increased mucus secretion?

Chronic bronchitis Signup and view all the answers

How do cigarette smoke affect ciliary function in the airways?

Inhibits or impairs ciliary function Signup and view all the answers

What is the term used to describe the mechanism for continuously moving trapped material in mucus toward the pharynx?

Mucociliary escalator Signup and view all the answers

What is the primary role of the mucus blanket in the airways?

To trap inhaled particles Signup and view all the answers

How are coughs and sneezes beneficial in moving mucous lining of the airways?

By expelling irritants and mucus from airways Signup and view all the answers

What are the natural mechanical defenses of the respiratory tract?

Filtration and impaction Signup and view all the answers

How do epithelial barriers and mucus contribute to defending the respiratory tract?

By limiting particle penetration Signup and view all the answers

Which cells are involved in the natural phagocytic defenses of the respiratory tract?

Macrophages Signup and view all the answers

What is the main function of type II alveolar epithelial cells in the lungs?

To actively pump sodium and water from the alveolar surface into the interstitium Signup and view all the answers

Which cell proliferates to reestablish a continuous epithelial surface in response to injury in the lung?

Type II alveolar cell Signup and view all the answers

What plays a role in removing material from the monolayer in the alveolus?

Macrophage Signup and view all the answers

What is the main role of type II alveolar epithelial cells in lung injury response?

Proliferation to reestablish continuous epithelial surface Signup and view all the answers

What happens if tracheobronchial secretions are not removed from a patient?

Airway obstruction will develop Signup and view all the answers

How does cigarette smoke affect alveolar macrophage function?

Inhibits their function Signup and view all the answers

What is the main role of alpha1 antitrypsin in the lungs?

Inactivates proteolytic enzymes Signup and view all the answers

How are biologically active contaminants of inspired air usually removed according to the text?

Through immunologic responses Signup and view all the answers

What is one way that particles reach the mucociliary escalator?

The alveolar fluid lining moves upward Signup and view all the answers

What is the main role of pulmonary surfactant?

Reducing alveolar elastic recoil Signup and view all the answers

Which chemical substrate in mixed venous blood is approximately 70% converted to angiotensin II after passing through the lung?

Angiotensin I Signup and view all the answers

'Hypoxia acts directly on pulmonary vascular smooth muscle cells by affecting what ion's permeability?'

$K^{+}$ Signup and view all the answers

Study Notes

Functions of the Upper Airways

Filters, humidifies, and warms inspired air to optimize conditions for gas exchange in the lungs.
Nasal turbinates increase surface area for air conditioning.

Metabolic Functions of the Lung

Plays a role in metabolizing various compounds and converting substrates in the blood.

Hazardous Materials in Inspired Air

Example includes pollutants, allergens, or airborne toxins that can pose health risks.

Lung Protection Mechanisms

The lung utilizes cilia and mucus to trap and expel contaminants from inspired air.
Alveolar macrophages actively phagocytize and clear pathogens and particles.

Lung as a Blood Filtration and Storage Site

The unique vascular structure and compliance allow the lungs to accommodate varying blood volumes and filter particles.

Pulmonary Circulation Reservoir Function

Acts as a reservoir for the left ventricle by accommodating fluctuations in blood flow and volume.

Protection of Systemic Circulation

Pulmonary circulation filters out harmful substances and reduces the load of potentially damaging particles entering systemic circulation.

Particles Filtered by Pulmonary Circulation

Large particles such as pollen and dust are typically filtered; smaller particles may pass through.

Prevention of Vascular Bed Occlusion

The lung employs mechanisms like phagocytosis to prevent blockage of blood vessels by filtered particles.

Function of Nasal Turbinates

Enhance airflow regulation and ensure air is conditioned before reaching the lungs.

Filtration of Larger Particles

Particles larger than 10 μm are generally trapped in the upper respiratory tract via mucus.

Depositing of Smaller Particles

Particles between 0.1 and 0.5 μm mainly deposit in the alveolar region.

Cough Stimulation

Cough reflex is triggered by irritation of the respiratory tract lining.

Primary Impaction Site for Larger Particles

The tracheobronchial region serves as the major site for larger particle impaction.

Removal of Particles 2 to 10 μm

Managed by the mucociliary clearance mechanism, involving cilia moving mucus upward.

Airway Secretions Production

Goblet cells and submucosal glands are primarily responsible for the secretion of mucus.

Synchronized Mucus Movement

Ciliary action leads to the coordinated movement of mucus, termed ciliary escalator.

Conditions Increasing Mucus Secretion

Chronic bronchitis may increase the number of goblet cells and mucous gland hypertrophy.

Effects of Cigarette Smoke on Ciliary Function

Impairs ciliary movement, reducing the efficiency of mucus clearance.

Continuous Movement of Trapped Material

The mucociliary escalator mechanism continuously transports trapped particles toward the pharynx.

Role of the Mucus Blanket

Serves as a protective layer trapping contaminants and facilitating their removal.

Benefits of Coughs and Sneezes

Both actions facilitate the expulsion of mucus and pathogens from the airways.

Natural Mechanical Defenses

Include physical barriers like the mucus layer and ciliary movement against pathogens.

Epithelial Barriers and Mucus Contribution

The epithelial lining acts as a barrier while mucus traps particles and pathogens.

Phagocytic Defenses in the Respiratory Tract

Alveolar macrophages and neutrophils are crucial in ingesting and destroying foreign materials.

Function of Type II Alveolar Epithelial Cells

Responsible for producing surfactant, reducing surface tension in alveoli, and preventing collapse.

Cell Response to Injury

Type II alveolar cells proliferate to restore the epithelial surface after lung injury.

Material Removal from Alveoli

Alveolar macrophages absorb and clear debris from the alveolar space.

Role of Type II Cells in Injury Response

Aid in lung repair by producing growth factors and surfactant.

Consequence of Secretions Not Being Removed

Accumulation can lead to infection, airway obstruction, and reduced gas exchange.

Cigarette Smoke and Macrophage Function

Deters macrophage function, increasing susceptibility to lung infections.

Role of Alpha1 Antitrypsin

Protects the lungs by inhibiting proteolytic enzymes, helping to maintain tissue integrity.

Removal of Biologically Active Contaminants

Typically accomplished through mucociliary clearance and phagocytosis.

Particles Reaching the Mucociliary Escalator

Particles can be captured in mucus and transported upwards by ciliary action.

Function of Pulmonary Surfactant

Reduces surface tension in alveoli, preventing collapse and aiding in gas exchange.

Angiotensin II Formation

Approximately 70% of angiotensin I is converted to angiotensin II by the lungs.

Hypoxia and Pulmonary Vascular Smooth Muscle

Directly affects calcium ion permeability in smooth muscle cells, leading to vasoconstriction.

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