Overview of the Respiratory System
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Questions and Answers

Which of the following structures is NOT a component of the conducting airways?

  • Alveoli (correct)
  • Bronchi
  • Larynx
  • Trachea

What is the primary role of the pulmonary arteries?

  • Carry oxygenated blood from the lungs to the left atrium
  • Distribute blood to the structures of the lungs
  • Carry oxygenated blood from the lungs to the left ventricle
  • Carry deoxygenated blood from the right ventricle to the lungs (correct)

What is the function of the mucociliary blanket in the conducting airways?

  • To trap bacteria, dust, and particles (correct)
  • To produce surfactant
  • To increase the surface area for gas exchange
  • To regulate the flow of air into and out of the lungs

Which of the following is a characteristic of the respiratory bronchioles?

<p>They participate in gas exchange (B)</p> Signup and view all the answers

Which of the following factors can negatively impact the function of cilia in the conducting airways?

<p>Cigarette smoking (A)</p> Signup and view all the answers

Which of the following statements about the diaphragm is TRUE?

<p>It is a flat sheet of muscle that contracts during inspiration (D)</p> Signup and view all the answers

Which of the following statements is TRUE about the difference between pulmonary arteries and pulmonary veins?

<p>Pulmonary arteries carry deoxygenated blood, while pulmonary veins carry oxygenated blood. (B)</p> Signup and view all the answers

Which of the following components are located in the mediastinum?

<p>Heart, esophagus, trachea (B)</p> Signup and view all the answers

What is the primary difference between pulmonary ventilation and alveolar ventilation?

<p>Pulmonary ventilation refers to the exchange of gases between the atmosphere and the lungs, while alveolar ventilation refers to the exchange of gases within the alveoli. (C)</p> Signup and view all the answers

Which of the following conditions is associated with a high V/Q ratio?

<p>A pulmonary thromboembolism (A)</p> Signup and view all the answers

What is the primary function of surfactant?

<p>To decrease the surface tension of the alveoli, making it easier to inflate the lungs (A)</p> Signup and view all the answers

What is the term for air that is moved during ventilation but does not participate in gas exchange?

<p>Anatomic dead space (B)</p> Signup and view all the answers

Which of the following is a characteristic of a physiologic shunt?

<p>Blood flowing through the lungs but not being oxygenated (A)</p> Signup and view all the answers

What is the main cause of alveolar dead space?

<p>A blocked pulmonary artery (A)</p> Signup and view all the answers

Which of the following best describes a low V/Q ratio?

<p>Areas of the lung are being perfused, but not ventilated (A)</p> Signup and view all the answers

What is the primary focus of a lung function test?

<p>To assess the overall health of the respiratory system (C)</p> Signup and view all the answers

What primarily contributes to the narrowing of the airway lumen during bronchospasm?

<p>Contraction of smooth muscle (A)</p> Signup and view all the answers

What is the primary role of Type I alveolar cells in the lungs?

<p>Facilitating gas exchange (D)</p> Signup and view all the answers

What happens to the compliance of the lungs in pulmonary fibrosis?

<p>It decreases (A)</p> Signup and view all the answers

Which muscles are primarily responsible for active expiration during intense physical activity?

<p>Internal intercostals and abdominal muscles (D)</p> Signup and view all the answers

Where does the majority of gas exchange occur in the lungs?

<p>Alveoli (A)</p> Signup and view all the answers

What is the primary role of central chemoreceptors in the respiratory system?

<p>To detect changes in carbon dioxide levels (A)</p> Signup and view all the answers

In which part of the respiratory tract does the greatest resistance to airflow occur?

<p>Medium-sized bronchi (C)</p> Signup and view all the answers

How does pulmonary surfactant affect lung compliance?

<p>Increases it by decreasing surface tension (B)</p> Signup and view all the answers

Which lung receptor is primarily responsible for reacting to irritants and prompting bronchoconstriction?

<p>Irritant receptors (D)</p> Signup and view all the answers

What primarily limits the flexibility of the thoracic cage in conditions like kyphoscoliosis?

<p>Decreased rib cage mobility (C)</p> Signup and view all the answers

What is the primary mechanism through which oxygen is transported in the blood?

<p>Bound to hemoglobin (B)</p> Signup and view all the answers

Which of the following accurately describes the mechanics of inspiration?

<p>Diaphragm contracts, decreasing intrathoracic pressure (C)</p> Signup and view all the answers

At what partial pressure of oxygen (PO2) is hemoglobin typically about 98% saturated?

<p>100 mm Hg (D)</p> Signup and view all the answers

Which of the following conditions can cause hypoxemia?

<p>High altitudes (A), V/Q mismatching (B), Decreased diffusion capacity (D)</p> Signup and view all the answers

What is the effect of obesity on chest wall compliance?

<p>It decreases compliance (D)</p> Signup and view all the answers

What is the normal range for arterial partial pressure of carbon dioxide (PaCO2)?

<p>35-45 mm Hg (B)</p> Signup and view all the answers

Which statement about alveoli is correct?

<p>They are the site for gas exchange (B)</p> Signup and view all the answers

What is the estimated total surface area of the adult lung's alveoli?

<p>50 to 100 square meters (B)</p> Signup and view all the answers

What typically increases the thickness of the alveolar capillary membrane, affecting gas diffusion?

<p>Pulmonary edema (B)</p> Signup and view all the answers

Which factor does NOT significantly affect the diffusion of gases across the alveolar-capillary membrane?

<p>Temperature of the body (D)</p> Signup and view all the answers

Which respiratory muscles are primarily engaged during quiet breathing?

<p>Diaphragm and external intercostals (B)</p> Signup and view all the answers

What happens to the tracheobronchial tree as it progresses further into the lungs?

<p>Decrease in cartilage amount (B)</p> Signup and view all the answers

How is carbon dioxide transported in the blood?

<p>Bound to hemoglobin, dissolved, and as bicarbonate (D)</p> Signup and view all the answers

What will likely happen if the arterial partial pressure of oxygen drops below normal levels?

<p>Decrease in oxygen transport to tissues (A)</p> Signup and view all the answers

Which component of the respiratory control mechanism operates automatically without voluntary input?

<p>Chemoreceptors (C)</p> Signup and view all the answers

What defines anemia in the context of oxygen transport?

<p>Decreased hemoglobin or red blood cell volume (C)</p> Signup and view all the answers

What is the function of stretch receptors in the respiratory system?

<p>To monitor lung inflation and establish breathing patterns (A)</p> Signup and view all the answers

What is the primary effect of administering high concentrations of oxygen?

<p>Increased partial pressure difference of oxygen (A)</p> Signup and view all the answers

What is the primary function of the mucociliary blanket in the conducting airways?

<p>To trap bacteria, dust, and other particles (C)</p> Signup and view all the answers

What is the function of the juxtacapillary or J-receptors?

<p>They sense lung congestion (D)</p> Signup and view all the answers

What is the term for the condition characterized by a reduction of arterial blood oxygen levels?

<p>Hypoxemia (D)</p> Signup and view all the answers

What is the term for the ease with which the lungs can be inflated?

<p>Compliance (A)</p> Signup and view all the answers

What is the correct definition of perfusion in relation to the respiratory system?

<p>The movement of blood through the lungs. (B)</p> Signup and view all the answers

Which structure is primarily responsible for gas exchange in the lungs?

<p>Alveoli. (B)</p> Signup and view all the answers

Which type of receptors are most sensitive to changes in carbon dioxide levels in the blood?

<p>Central chemoreceptors. (C)</p> Signup and view all the answers

What is the main function of pulmonary surfactant?

<p>Decreases surface tension in the alveoli, enabling easier lung inflation. (B)</p> Signup and view all the answers

Which muscle is primarily responsible for inspiration during normal breathing?

<p>Diaphragm. (D)</p> Signup and view all the answers

What best describes the concept of airway resistance?

<p>The resistance to airflow along the conducting airways. (A)</p> Signup and view all the answers

Which location plays a critical role in integrating the diaphragm's function during ventilation?

<p>Medulla and pons. (B)</p> Signup and view all the answers

In which part of the respiratory system does the majority of gas exchange occur?

<p>Alveoli. (B)</p> Signup and view all the answers

Flashcards

What is the main purpose of the respiratory system?

The primary function of this system is to take in oxygen for the body's cells and remove carbon dioxide, a byproduct of cellular activity.

What is ventilation?

This process involves the movement of air into and out of the lungs.

What is perfusion?

This process involves the flow of blood through the lungs.

What is diffusion?

This process involves the transfer of gases between the lungs and the blood.

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What are conducting airways?

These are the portions of the respiratory system where air moves but gas exchange doesn't happen. These include the larynx, trachea, and bronchi.

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What are respiratory tissues?

These are the parts of the respiratory system that are involved in gas exchange. This includes the respiratory bronchioles and alveoli.

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What are non-respiratory bronchioles?

These are the smallest conducting airways that do not participate in gas exchange.

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What is the mucociliary blanket?

This protective layer in the airways traps harmful particles like bacteria and dust.

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Pulmonary ventilation

The total exchange of gases between the atmosphere and the lungs.

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Alveolar ventilation

The exchange of gases within the alveoli, specifically between the alveoli and the external environment.

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V/Q mismatch

A mismatch between ventilation and perfusion, leading to inefficient gas exchange.

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Dead space

Air moving through the lungs but not participating in gas exchange.

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Shunt

Blood moving from the right to the left side of the circulation without being oxygenated.

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Atelectasis

A collapse of lung units, often caused by airway obstruction or loss of surfactant.

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Physiological shunt

Areas of the lung being perfused but not ventilated, leading to a low V/Q ratio.

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Matched ventilation and perfusion

The state where ventilation and perfusion are optimally matched, ensuring efficient gas exchange.

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How does cigarette smoke impact cilia?

Cilia are tiny hair-like structures that line the airways, helping to move mucus and trapped particles out of the lungs. Cigarette smoke can damage or paralyze these cilia, leading to a build-up of debris and increasing the risk of lung infections.

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What is the tracheobronchial tree?

The tracheobronchial tree is a branching network of tubes that carries air to and from the lungs. It consists of the trachea, bronchi, and bronchioles.

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Describe the bronchi.

The bronchi are the main branches of the trachea, leading to the lungs. They are lined with cartilage and smooth muscle.

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What are bronchioles?

Bronchioles are smaller airways that branch off from the bronchi. They lack cartilage and are mainly composed of smooth muscle and elastic fibers.

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What is bronchospasm?

Bronchospasm is the narrowing of the airways due to the contraction of smooth muscle. It can occur during asthma attacks or allergic reactions.

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What are respiratory airways?

The respiratory airways are the parts of the tracheobronchial tree where gas exchange takes place. They include the respiratory bronchioles, alveoli, and pulmonary capillaries.

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What are alveoli?

The alveoli are tiny air sacs in the lungs where gas exchange occurs. Oxygen diffuses from the alveoli into the blood, while carbon dioxide diffuses from the blood into the alveoli.

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What do Type I alveolar cells do?

Type I alveolar cells are thin, flat cells responsible for gas exchange. They form the barrier between the air in the alveoli and the blood in the capillaries.

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What is the function of Type II alveolar cells?

Type II alveolar cells produce pulmonary surfactant, a substance that reduces surface tension in the alveoli. This makes it easier to inflate the lungs and helps prevent the alveoli from collapsing.

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Describe the process of inspiration.

Inspiration is the active process of breathing in. It involves the contraction of the diaphragm and external intercostal muscles, which expands the chest cavity and draws air into the lungs.

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Describe the process of expiration.

Expiration is the process of breathing out. Usually, it is a passive process driven by the elastic recoil of the lungs and chest wall.

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What is compliance in the respiratory system?

Compliance refers to the ease with which something can be stretched or distorted. In the respiratory system, it refers to the ease with which air can move into and out of the lungs.

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What factors influence lung compliance?

Lung compliance is influenced by the elasticity of the lung tissue. Elastin fibers allow the lungs to stretch easily, while collagen fibers resist stretching. Lung compliance can be affected by conditions like fibrosis and emphysema.

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What is airway resistance?

Airway resistance is the impediment to airflow through the airways. The greatest resistance occurs in the medium-sized bronchi. Factors like bronchospasm and mucus buildup can contribute to increased airway resistance.

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Why smaller airways don't contribute much to resistance?

Smaller airways, despite their numerous branches, have a larger total cross-sectional area, which reduces their resistance to airflow.

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Where is the respiratory center located?

The respiratory center, located in the medulla and pons, controls breathing through signals to the diaphragm and other muscles.

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How is breathing controlled?

Breathing can be consciously controlled by the motor and premotor cortex, but typically operates automatically.

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What do chemoreceptors do?

Chemoreceptors monitor blood levels of pH, oxygen, and carbon dioxide, influencing breathing rate.

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Where are central chemoreceptors located?

Central chemoreceptors, found in the medulla, are most sensitive to carbon dioxide levels in the blood.

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Where are peripheral chemoreceptors found?

Peripheral chemoreceptors, located in the carotid and aortic bodies, primarily monitor oxygen levels in the blood.

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What do stretch receptors do?

Stretch receptors in the airways sense lung inflation, contributing to breathing patterns and minimizing breathing effort.

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What do irritant receptors do?

Irritant receptors, located in the airways, trigger bronchoconstriction, mucus secretion, and coughing in response to irritating substances.

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What do J receptors do?

Juxtacapillary (J) receptors in the alveolar walls sense lung fluid buildup, causing rapid shallow breathing and a slower heart rate during inhalation.

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What are the essential processes of gas exchange?

Ventilation, perfusion, and diffusion are the key processes in the respiratory system for gas exchange between lungs and blood.

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What is diffusion in the respiratory system?

Diffusion is the movement of gases from an area of higher partial pressure to lower partial pressure.

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What is atmospheric pressure?

The combined pressure of all gases in the air is atmospheric pressure, which is 760 mm Hg at sea level.

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What is partial pressure?

The pressure exerted by a single gas within a mixture of gases is known as its partial pressure.

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What factors impact gas diffusion?

The surface area available for gas exchange, the thickness of the alveolar-capillary membrane, and the diffusion coefficient of the gas all influence diffusion rates.

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How are oxygen and carbon dioxide transported in blood?

Oxygen is carried in the blood both dissolved in plasma and bound to hemoglobin, while carbon dioxide is transported in dissolved form, bound to hemoglobin, and as bicarbonate.

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Lung Compliance

The ease with which the lungs can be inflated, essentially how stretchy they are.

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Hypoxemia

A condition where the blood's oxygen levels are reduced. This can be due to various reasons such as lung disease, heart problems, or altitude.

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What is the primary muscle responsible for inspiration?

The primary muscle responsible for inhalation is the diaphragm, a dome-shaped muscle that contracts to expand the chest cavity, drawing air into the lungs.

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J Receptors

The receptors located in the lung's alveolar walls which sense any fluid buildup, triggering rapid, shallow breathing and a slower heart rate.

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Mucociliary Blanket

The layer of mucus and cilia that lines the airways, trapping bacteria, dust, and other harmful particles.

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What is pulmonary surfactant?

Pulmonary surfactant, a substance produced by type II alveolar cells, decreases surface tension in the alveoli, making it easier for the lungs to inflate and preventing them from collapsing.

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What is the primary function of type I alveolar cells?

Type I alveolar cells are thin, flat cells primarily responsible for gas exchange, allowing oxygen to move from the alveoli into the blood and carbon dioxide to move from the blood into the alveoli.

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Study Notes

Respiratory System Overview

  • Primary Function: Uptake of oxygen for tissue metabolism and removal of carbon dioxide (a metabolic byproduct). Accomplished via ventilation, perfusion, and diffusion. This is the correct answer for Question 1.
  • Ventilation: Movement of gases into and out of the lungs. This is the correct answer for Question 3.
  • Perfusion: Movement of blood through the lungs. This is the correct answer for Question 4.
  • Diffusion: Transfer of gases between lungs and blood.

Components of the Respiratory System

  • Lungs: Contain conducting airways and respiratory tissues.
  • Conducting Airways: Pass air but don't exchange gases. Includes larynx, trachea, and bronchi. These are the correct answers for Question 2. Warm, humidify, and filter inhaled air using mucus and cilia. This is the correct answer for Question 11.
  • Respiratory Tissues: Involved in gas exchange. Includes respiratory bronchioles and alveoli.
  • Alveoli: Terminal airspaces, site of gas exchange, are not part of conducting airways, as stated in Question 2.
  • Pulmonary Vascular System:
    • Pulmonary Arteries: Carry deoxygenated blood to lungs.
    • Pulmonary Veins: Return oxygenated blood to the heart's left atrium.
    • Bronchial Circulation: Supplies blood to lung structures.
  • Rib Cage & Respiratory Muscles:
    • Diaphragm, intercostals, accessory muscles: Drive breathing movements. The diaphragm is the correct answer in response to Question 5.

Conducting Airways

  • Structure: Nasopharyngeal airways, larynx, and tracheobronchial tree. Smallest conducting pathways are non-respiratory bronchioles.
  • Lining: Epithelium with mucus secreting glands, ciliated cells, and serous glands. The mucociliary blanket traps particles and cilia move it toward the oropharynx, this is the function in response to Question 11. Cilia function is affected by oxygen levels, dryness, and smoking. Cigarette smoking can impair cilia function, leading to residue buildup and respiratory problems (COPD).
  • Mucociliary Blanket: Traps particles, cilia move it toward the oropharynx.
  • Airway Changes: Epithelial type changes from bronchi to bronchioles to alveoli.
  • Cilia Function: Affected by oxygen levels, dryness, and smoking. Cigarette smoking can impair cilia function, leading to residue buildup and respiratory problems (COPD).

Airway Walls

  • Structure: Cartilage, elastic and collagen fibers, smooth muscle.
  • Changes with branching: Cartilage decreases, smooth muscle and elastic tissue increase as airways branch.
  • Bronchioles: No cartilage, mostly smooth muscle. Airway resistance occurs primarily at the medium-sized bronchi, as seen in response to Question 9. .
  • Bronchospasm: Smooth muscle contraction narrows airways, impairing airflow.

Tracheobronchial Tree

  • Structure: Trachea, bronchi, bronchioles. 23 generations of branching.
  • Function: Extensive branching increases cross-sectional area for large gas exchange surface.

Respiratory Airways

  • Lobule: Smallest functional lung unit, contains respiratory bronchioles, alveoli, pulmonary capillaries.
  • Alveoli: Terminal airspaces, site of gas exchange.
  • Alveolar Cells: Type I cells perform gas exchange, Type II cells produce surfactant for lung inflation and immune function. The primary function of type I alveolar cells is gas exchange, aligning with Question 10.
  • Surfactant: Reduces surface tension for easier lung inflation, crucial for newborns' respiration. Surfactant decreases surface tension, allowing for easier lung inflation as seen in response to Question 8.

Mechanics of Breathing

  • Chest Cavity: Closed compartment, trachea is the only air entry point.
  • Inspiration: Diaphragm contracts, chest expands, reducing intrathoracic pressure, drawing air into the lungs.
  • Expiration: Diaphragm relaxes, chest recoils, increasing intrathoracic pressure, forcing air out.
  • Bellows Analogy: Demonstrates pressure changes driving air movement.
  • Expiration (Active): Usually passive, but can be active in activities involving exertion or forceful exhalation.

Respiratory Muscles

  • Diaphragm: Principal muscle of inspiration, in response to Question 5.
  • External Intercostals: Raise ribs, push sternum outward.
  • Accessory Muscles: Sternocleidomastoid, scalene; support breathing during exercise/stress.
  • Respiratory Distress: Use of accessory muscles indicates respiratory difficulty.

Compliance

  • Definition: Ease of stretching/distortion. Lung compliance is the ease of lung inflation (Question 12).
  • Lung Compliance: Ease of lung inflation.
  • Elastin: Stretches easily.
  • Collagen: Resists stretching.
  • Elastic Recoil: Ability to return to initial position after stretch.
  • Decreased Compliance: Diseases like pulmonary fibrosis (scar tissue), emphysema (lost elasticity).
  • Factors affecting compliance: Surface tension (higher surface tension, decreased compliance), pulmonary surfactant (decreases surface tension, increased compliance).

Airway Resistance

  • Definition: Impediment to airflow.
  • Major Site of Resistance: Medium-sized bronchi, in response to Question 9.
  • Smaller Airways: Branching increases cross-sectional area, decreasing resistance.

Control of Breathing

  • Respiratory Center: Medulla and pons; integrate diaphragm and muscle actions, regulate ventilation. This is the correct answer to Question 6.
  • Control Components: Automatic (chemoreceptors, lung receptors) and voluntary (cortex).
  • Chemoreceptors: Monitor blood pH, O2, and CO2 levels. Central chemoreceptors are most crucial for detecting changes in CO2 (Question 7).
  • Lung Receptors: Monitor lung function and breathing patterns (stretch, irritant, J-receptors). J-receptors monitor lung congestion (Question 14).

Ventilation and Gas Exchange

  • Diffusion: Movement across alveolar-capillary membrane.
  • Partial Pressures: Pressure exerted by individual gases in a mixture. Crucial for diffusion, especially O2 and CO2.
  • Factors Affecting Diffusion: Surface area, membrane thickness, gas diffusion coefficient.
  • Lung Damage/Impairments: Diminished gas exchange surface area and increased membrane thickness impact diffusion.

Oxygen Transport

  • Poor Solubility: Oxygen poorly soluble in blood (only 1-2% in dissolved form).
  • Hemoglobin: 98-99% of oxygen is bound to this protein in red blood cells (4 oxygen molecules/hemoglobin).
  • Oxygen-Hemoglobin Dissociation Curve: Describes relationship between hemoglobin saturation (SO2) and arterial oxygen partial pressure (PO2).
  • Hypoxemia: Low arterial blood oxygen. This is the correct response to Question 15.

Carbon Dioxide Transport

  • High Solubility: Higher solubility than oxygen (20 times higher). Transported as dissolved CO2, bound to hemoglobin, and bicarbonate.

Ventilation-Perfusion Matching

  • V/Q Ratio: The ratio of ventilation (air flow in alveoli) to perfusion (blood flow through capillaries).
  • Matching: Essential for efficient gas exchange.
  • V/Q Mismatch: Different regions of the lungs have varying V/Q ratios.
  • Dead Space: Air moved in/out that does not participate in gas exchange (anatomical/alveolar).

Pulmonary Shunt

  • DefinitionBlood bypasses lung tissue without oxygenating.

Lecture Summary

  • Overview of respiratory physiology, including respiratory anatomy, mechanics, control of breathing, and gas handling. This is a preparatory lecture for later discussions on pulmonary function tests, obstructive lung conditions, and restrictive diseases.

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Description

This quiz covers the key functions and components of the respiratory system, including ventilation, perfusion, and diffusion. It also explores the anatomy of the lungs and the pulmonary vascular system. Test your understanding of how these elements contribute to gas exchange and overall respiratory health.

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