Respiratory System Overview

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Questions and Answers

What is the primary role of the respiratory system regarding gases?

  • To prevent gas exchange between the atmosphere and the blood.
  • To allow oxygen to diffuse into the blood and carbon dioxide to diffuse into the bronchial tree. (correct)
  • To facilitate the exchange of carbon monoxide for oxygen in the bloodstream.
  • To allow oxygen to diffuse out of the blood and carbon dioxide to diffuse into it.

Which of the following sequences accurately represents the path of air through the respiratory system?

  • Larynx → trachea → nasal cavity → primary bronchi → lungs.
  • External nares → larynx → trachea → primary bronchi → nasal cavity.
  • Nasal cavity → nasaopharynx → laryngopharynx → larynx → external nares.
  • External nares → nasal cavity → nasaopharynx → laryngopharynx → larynx. (correct)

What is the main purpose of the pleural fluid found in the pleural cavity?

  • To increase friction between the pleural membranes allowing for easier lung expansion.
  • To actively transport oxygen from the lungs into the bloodstream.
  • To facilitate the diffusion of carbon dioxide into the alveoli of the lungs.
  • To minimize friction between the lung tissues and maintain surface tension to prevent lung collapse. (correct)

What is the role of surfactant in the lungs?

<p>To lower the surface tension in the pleural cavity. (A)</p> Signup and view all the answers

Which structure is NOT considered to be part of the direct pathway of air during respiration?

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

Which type of epithelium lines the respiratory tract from the trachea to the tertiary bronchi?

<p>Ciliated pseudostratified columnar epithelium (D)</p> Signup and view all the answers

What is the primary function of the simple squamous epithelium that lines the alveoli?

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

According to Boyle's law, what happens to the pressure within a gas when the volume of the container increases, assuming temperature remains constant?

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

What is the role of the diaphragm in breathing?

<p>It facilitates the control of thoracic volume. (D)</p> Signup and view all the answers

Which action leads to a decrease of pressure within the lung (intraalveolar pressure) during inspiration (inhalation)?

<p>Contraction of the diaphragm and external intercostals (C)</p> Signup and view all the answers

Why does the bronchial tree from primary bronchi to tertiary bronchi require cartilage rings for support?

<p>Due to the large diameter of their lumina (A)</p> Signup and view all the answers

What are the bronchioles lined by?

<p>Cuboidal epithelium (B)</p> Signup and view all the answers

Which of the following describes the direction of gas diffusion of gas molecules?

<p>From a higher pressure area to a lower pressure area (C)</p> Signup and view all the answers

During expiration, what causes air to move out of the lungs?

<p>An increase in intra-alveolar pressure above atmospheric pressure. (A)</p> Signup and view all the answers

According to the gas law, what pressure relationship promotes air movement into the lungs?

<p>Intra-alveolar pressure is lower than atmospheric pressure. (A)</p> Signup and view all the answers

What is the primary mechanism through which normal quiet breathing is accomplished?

<p>Movement of the diaphragm only. (D)</p> Signup and view all the answers

What effect does contraction of the diaphragm have on the volume of the intrapleural cavity during inspiration?

<p>It increases the volume. (C)</p> Signup and view all the answers

If a person inhales maximally after a normal inspiration, which lung volume are they using?

<p>Inspiratory reserve volume. (A)</p> Signup and view all the answers

What is the approximate average volume of air that moves in and out of the lungs during normal breathing?

<p>500 ml (B)</p> Signup and view all the answers

During expiration, the relaxation of the diaphragm and intercostal muscles results in which change to the thoracic volume?

<p>Decreased thoracic volume. (D)</p> Signup and view all the answers

What does a spirometer measure?

<p>Lung capacities and volumes (C)</p> Signup and view all the answers

If a patient has an inspiratory capacity of 4500 ml and a tidal volume of 3200 ml, what is their inspiratory reserve volume?

<p>1300 ml (A)</p> Signup and view all the answers

Which of the following is NOT a component of the vital capacity (VC)?

<p>Residual Volume (RV) (B)</p> Signup and view all the answers

A patient's total lung capacity (TLC) is measured at 7000 ml, and their vital capacity (VC) is 5200 ml. What is their residual volume?

<p>1800 ml (A)</p> Signup and view all the answers

Which of the following best describes the physiologic dead space?

<p>The sum of the anatomic and alveolar dead spaces. (B)</p> Signup and view all the answers

According to the content, what happens to normal breathing when the level of carbon dioxide (CO2) in the blood decreases?

<p>Normal breathing is inhibited. (C)</p> Signup and view all the answers

If a person's lungs and thoracic walls relax, what effect does this have on their breathing, according to the content?

<p>Breathing is stimulated. (A)</p> Signup and view all the answers

A patient's expiratory reserve volume is measured at 1300ml. Which statement is correct?

<p>This is the amount of air they can exhale after a normal exhale. (B)</p> Signup and view all the answers

If a person has a decreased level of oxygen (O2) in their blood, what is the expected effect on their breathing, according to the content?

<p>Breathing could be stimulated. (C)</p> Signup and view all the answers

What is the primary effect of increased CO2 diffusion from blood into cerebrospinal fluid (CSF)?

<p>Lowering of CSF pH by formation of carbonic acid. (B)</p> Signup and view all the answers

What is the effect of a decrease in blood pH on peripheral chemoreceptors?

<p>They are stimulated irrespective of blood CO2 levels. (A)</p> Signup and view all the answers

Why are chemoreceptors in the medulla unaffected by changes in blood pH?

<p>The H+ ions cannot cross the blood-brain barrier. (D)</p> Signup and view all the answers

How does low blood PO2 affect the chemoreceptor response to increased blood PCO2?

<p>Low blood PO2 augments the chemoreceptor response to increased PCO2. (C)</p> Signup and view all the answers

What is the definition of pulmonary ventilation?

<p>The amount of air moved in and out of the lungs per minute. (D)</p> Signup and view all the answers

What is the relationship between increased metabolism and ventilation?

<p>Increased metabolism leads to increased ventilation due to increased plasma CO2. (B)</p> Signup and view all the answers

According to Dalton's Law, what determines the direction of gas diffusion in the lungs and body tissues?

<p>The differences in partial pressure of each individual gas. (C)</p> Signup and view all the answers

What is the critical role of oxygen in internal respiration that involves the release of energy?

<p>It is critical in the release of ATP from energy molecules. (D)</p> Signup and view all the answers

Approximately what percentage of hemoglobin (Hb) is saturated with oxygen (O2) at an O2 partial pressure of 40 mmHg?

<p>75% (C)</p> Signup and view all the answers

Which of the following factors would cause a shift in the oxygen-hemoglobin dissociation curve to the right?

<p>Increased CO2 pressure (B)</p> Signup and view all the answers

What is the phenomenon called when the oxygen-hemoglobin dissociation curve shifts to the right, resulting in less hemoglobin saturation and increased O2 release?

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

What percentage of carbon dioxide (CO2) is transported in the blood by binding to hemoglobin?

<p>23% (C)</p> Signup and view all the answers

What is the primary role of carbonic anhydrase (CA) in the transport of carbon dioxide (CO2)?

<p>Accelerating the conversion of carbonic acid to hydrogen and bicarbonate ions (A)</p> Signup and view all the answers

Which of the following best describes the Haldane effect?

<p>Increased hemoglobin saturation and less O2 release (A)</p> Signup and view all the answers

Considering the oxygen-hemoglobin saturation curve, at what point does it begin to flatten out, indicating that hemoglobin is nearly fully saturated with oxygen (O2)?

<p>80 mmHg (A)</p> Signup and view all the answers

What is the direct product of carbon dioxide (CO2) reacting with water (H2O) within erythrocytes?

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

Flashcards

Inspiration

The process of taking air into the lungs, expanding the chest cavity.

Expiration

The process of expelling air from the lungs, reducing the chest cavity.

Gas Exchange

The exchange of oxygen and carbon dioxide between the lungs and the bloodstream.

Parietal Pleura

A thin, slippery membrane that lines the thoracic cavity, surrounding the lungs.

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Visceral Pleura

A thin, slippery membrane that covers the surface of the lungs.

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Ciliated Pseudostratified Columnar Epithelium

Type of tissue that lines the trachea, primary, secondary, and tertiary bronchi.

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Cuboidal Epithelium

Type of tissue that lines the bronchioles.

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Simple Squamous Epithelium

Type of tissue that lines the alveolar ducts and alveoli.

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Diaphragm

A sheet of skeletal muscle that separates the thoracic cavity from the abdominal cavity.

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Bronchi

Branches off of the trachea that carry air into the lungs.

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Bronchioles

Smallest air passages in the lungs.

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Alveoli

Tiny air sacs in the lungs where gas exchange takes place.

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Inspiration (Inhalation)

The process of breathing in, where air is drawn into the lungs.

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Expiration (Exhalation)

The increase in pressure within the alveoli, pushing air out into the atmosphere.

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Pulmonary Ventilation

The process of moving air between the atmosphere and the alveoli of the lungs.

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Tidal Volume (TV)

The amount of air inhaled or exhaled in a normal breath.

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Inspiratory Reserve Volume (IRV)

The extra amount of air you can inhale after a normal breath.

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What causes expiration?

The increase of pressure within the alveoli, pushing air out.

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What causes inspiration?

The decrease of pressure within the alveoli, pulling air in.

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Spirometer

A device used to measure lung capacities and air volumes.

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Partial Pressure (pp)

The pressure exerted by a single gas in a mixture of gases.

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External Respiration

The movement of oxygen from the alveoli into the capillaries and carbon dioxide from the capillaries into the alveoli in the lungs.

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Internal Respiration (Tissue Respiration)

The movement of oxygen from the capillaries into the tissue cells and carbon dioxide from the tissue cells into the capillaries in the body.

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Carbon Dioxide (CO2)

A byproduct of metabolism that can become harmful in large quantities.

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Cellular Respiration

The process by which cells use oxygen to release energy from food molecules.

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Respiratory Membrane

A thin membrane formed by the walls of alveoli and capillaries where gas exchange occurs.

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Dalton's Law

The law that states that the total pressure of a gas mixture is equal to the sum of the partial pressures of each gas in the mixture.

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Inspiratory Capacity (IC)

The amount of air that can be inhaled after a normal inhalation. It's the sum of tidal volume (TV) and inspiratory reserve volume (IRV).

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Vital Capacity (VC)

The total amount of air that can be exhaled after a maximum inhalation. It's the sum of tidal volume (TV), inspiratory reserve volume (IRV), and expiratory reserve volume (ERV).

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Residual Volume (RV)

The amount of air that remains in the lungs even after a maximal exhalation.

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Total Lung Capacity (TLC)

The total amount of air in the lungs at any given time. It's the sum of vital capacity (VC) and residual volume (RV).

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Anatomic Dead Space

The air in the airways (bronchi and bronchioles) that doesn't participate in gas exchange. It's like a 'dead zone' for gas exchange.

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Alveolar Dead Space

The air in the alveoli (air sacs) that doesn't participate in gas exchange. It's like air trapped in the sacs, unable to reach the blood.

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Physiological Dead Space

The total amount of air in the lungs that doesn't participate in gas exchange. It's the sum of anatomical dead space and alveolar dead space.

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Factors Inhibiting Normal Breathing

Stretching of the lungs and thoracic walls, increased oxygen level in the blood, and decreased carbon dioxide and hydrogen ion levels.

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Oxygen-Hemoglobin Dissociation Curve

The relationship between the partial pressure of oxygen (PO2) and the saturation of hemoglobin (Hb) in the blood. It shows how much oxygen binds to hemoglobin at different PO2 levels.

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Bohr Effect

The phenomenon where the oxygen-hemoglobin dissociation curve shifts to the right, leading to less Hb saturation and more oxygen release. It occurs under conditions like low pH, high CO2, or high temperature.

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Haldane Effect

The phenomenon where the oxygen-hemoglobin dissociation curve shifts to the left, leading to more Hb saturation and less oxygen release. This is less common and occurs under conditions like high pH and low CO2.

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Hemoglobin's Dual Binding

The ability of hemoglobin to bind to both oxygen and carbon dioxide. However, when CO2 binds to hemoglobin, it forms carbaminohemoglobin, a molecule with a bluish pigment.

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Carbon Dioxide Transport

The process of carbon dioxide transport in the blood. About 7% dissolves in plasma, 23% binds to hemoglobin, and 70% is converted to bicarbonate ions.

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Carbonic Anhydrase (CA)

An enzyme found in red blood cells that catalyzes the conversion of carbon dioxide and water into carbonic acid, which then dissociates into bicarbonate ions and hydrogen ions.

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Chloride Anion (Cl-)

A negative ion (anion) that plays a role in maintaining blood pH and ionic balance. It diffuses into blood plasma to replace the bicarbonate ions that move out of the red blood cells.

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Carbaminohemoglobin

A molecule formed when carbon dioxide binds to hemoglobin. It's responsible for the bluish pigment observed in the blood carrying a significant amount of CO2.

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Study Notes

Respiratory System

  • The respiratory system facilitates gas exchange between the environment and the body, enabling oxygen uptake and carbon dioxide removal.
  • Inspiration expands the thoracic cavity, drawing air into the bronchial tree.
  • Gas exchange occurs at the respiratory membrane, with oxygen entering the bloodstream and carbon dioxide exiting.
  • Expiration decreases thoracic volume, expelling air from the lungs.

Respiratory System Anatomy

  • The respiratory system structures form a branching network in the lungs.
  • Airway components: external nares, nasal cavity, nasopharynx, laryngopharynx, larynx, trachea, primary bronchi, secondary bronchi, tertiary bronchi, bronchioles, alveolar sacs, and alveoli.

Lung Structure

  • Lungs are cone-shaped organs in the thoracic cavity.
  • The thoracic cavity's surface, lining is parietal pleura, while the lung surfaces have visceral pleura.
  • Pleural fluid minimizes friction during breathing.
  • Surfactant reduces surface tension, preventing lung collapse.

Histology of Respiratory Tract

  • The respiratory tract's structure progresses from ciliated pseudostratified columnar epithelium to cuboidal epithelium.
  • Lastly, simple squamous epithelium lines the alveoli, facilitating gas exchange.
  • The diaphragm, a skeletal muscle, aids in breathing.

Breathing Mechanisms

  • Boyle's law explains gas movement in relation to pressure and volume changes.
  • Inspiration involves contraction of the diaphragm and intercostal muscles, increasing thoracic volume and decreasing intra-alveolar pressure.
  • Expiration is a passive process involving elastic recoil of the lungs and diaphragm, decreasing thoracic volume and increasing intra-alveolar pressure.

Pulmonary Ventilation

  • Pulmonary ventilation describes air exchange between the atmosphere and alveoli.
  • Normal breathing depends on diaphragm and intercostal muscle movements.
  • Lung capacities, measured by a spirometer, provide information about respiratory function.

Lung Capacities

  • Tidal volume (TV): the amount of air inhaled and exhaled during normal breathing.
  • Inspiratory reserve volume (IRV): air volume inhaled beyond normal inspiration.
  • Expiratory reserve volume (ERV): extra air exhaled after normal expiration.
  • Inspiratory capacity (IC): total amount of air that can be inhaled
  • Vital capacity (VC): total amount of air that can be exhaled
  • Residual volume (RV): the air remaining in the lungs after maximum exhalation.
  • Total lung capacity (TLC): the total air volume contained within the lungs.

Control of Breathing

  • Breathing is involuntary, regulated by centers in the pons and medulla oblongata.
  • Four primary factors control respiratory rate: stretch receptors in the lungs and thoracic walls, blood oxygen (O2), blood carbon dioxide (CO2), and blood hydrogen (H+) ions.
  • Chemoreceptors are important for controlling ventilation based on these factors.

Chemoreceptors

  • Central chemoreceptors respond to changes in pH in cerebrospinal fluid, linked to CO2 levels.
  • Peripheral chemoreceptors in the carotid and aortic bodies respond to changes in O2, CO2, and pH in the blood.

Gas Exchange in the Alveoli

  • Gas exchange occurs in the alveoli across the respiratory membrane, due to differences in partial pressure between the alveoli and surrounding capillaries.
  • Oxygen diffuses from the alveoli into the blood, and carbon dioxide diffuses from the blood into the alveoli.

Gas Transport

  • Oxygen is primarily transported by hemoglobin in red blood cells.
  • Carbon dioxide transport involves dissolved CO2, carbaminohemoglobin, and bicarbonate ions.
  • The oxygen-hemoglobin dissociation curve shows how oxygen binding to hemoglobin changes with varying oxygen partial pressures.

Carbon Monoxide

  • Carbon monoxide (CO) binds to hemoglobin more strongly than oxygen, hindering oxygen transport.

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