Practice Questions Exam 4

Questions and Answers

What is the primary function of Type I Pneumocytes in the lungs?

Diffusion of gases (correct)

Movement of mucus

Production of Surfactant

Supporting tracheal structure

What is the best indicator of overall lung function according to a spirogram?

Residual Volume (RV)

Functional Residual Capacity (FRC)

Forced Vital Capacity (FVC) (correct)

Tidal Volume (TV)

What type of epithelium is responsible for the movement of mucus in the respiratory tract?

Stratified Squamous Epithelium

Cuboidal Epithelium

Simple Cuboidal Epithelium

Psuedostratified Ciliated Columnar Epithelium (correct)

What is the name of the nerve that controls the diaphragm?

Phrenic Nerve Signup and view all the answers

What law explains the increase in oxygen diffusion in the lungs when a patient is given oxygen via nasal cannula?

Henry's Law Signup and view all the answers

What stimulates the medulla to increase breathing rate during exercise?

Increase in blood carbon dioxide levels Signup and view all the answers

What is the term for the volume of air left in the lungs after a normal exhalation?

FRC (Functional Residual Capacity) Signup and view all the answers

What type of muscle is the diaphragm?

Skeletal muscle Signup and view all the answers

What is the term for the drive to breathe that occurs in response to low oxygen levels in the blood?

Hypoxemic Drive Signup and view all the answers

What is the modern way to assess vital capacity?

FEV6 (Forced Expiratory Volume in 6 seconds) Signup and view all the answers

According to Boyle's Law, what happens to the pressure inside the lungs when you breathe in?

Pressure decreases. Signup and view all the answers

Which of the following statements accurately describes the relationship between alveolar air pressure and alveolar size, according to LaPlace's Law?

Alveolar air pressure is inversely proportional to alveolar size. Signup and view all the answers

What is the primary function of pulmonary surfactant?

To decrease alveolar surface tension. Signup and view all the answers

Which cranial nerve is responsible for controlling the vocal cords?

Vagus Nerve (CN X) Signup and view all the answers

The Hering-Breuer reflex primarily controls which aspect of breathing?

The depth of inspiration. Signup and view all the answers

Which of the following cranial nerves are involved in transmitting information about blood gas levels (CO2, H+, O2) to the medulla?

Glossopharyngeal Nerve (CN IX) and Vagus Nerve (CN X) Signup and view all the answers

What is the primary reason for the decrease in oxygen concentration (partial pressure) as you inhale room air?

Oxygen is diluted by water vapor and mixes with residual air in the lungs. Signup and view all the answers

Which of the following is NOT a factor that influences alveolar air pressure, according to LaPlace's Law?

The volume of air inhaled. Signup and view all the answers

What is the primary role of the medulla in the neural control of breathing?

To regulate the rhythm and depth of breathing. Signup and view all the answers

How does the Hering-Breuer reflex contribute to the regulation of breathing?

It prevents overinflation of the lungs. Signup and view all the answers

Which of the following is a primary characteristic of Respiratory Distress Syndrome (RDS) in newborns?

Collapse of tiny air sacs (alveoli) due to inadequate surfactant Signup and view all the answers

What is the primary physiological mechanism responsible for regulating breathing rate during exercise?

Increased carbon dioxide levels in the blood Signup and view all the answers

Which of the following is NOT a factor directly involved in the mechanics of breathing (inspiration and expiration)?

Action of the heart in pumping blood Signup and view all the answers

Which of the following accurately describes the effect of surfactant on alveolar stability?

Surfactant decreases surface tension, making alveoli less likely to collapse. Signup and view all the answers

What is the primary reason for the increased breathing rate at high altitude?

Decreased oxygen partial pressure in the air Signup and view all the answers

Which of the following correctly describes the relationship between alveolar pressure and lung volume during inspiration?

Alveolar pressure decreases as lung volume increases. Signup and view all the answers

Which of the following best describes the physiological changes that occur in the lungs during a bout of vigorous exercise?

Increased breathing rate and increased cardiac output Signup and view all the answers

What is the primary function of the cricoid cartilage in the larynx?

To provide support for the vocal cords Signup and view all the answers

What physiological change occurs as a result of hypercapnea?

Increased breathing rate Signup and view all the answers

What is the primary function of the receptors in the Aorta and Carotids with respect to breathing?

To provide feedback about CO2 and pH levels Signup and view all the answers

Which cranial nerve is responsible for relaying information from the stretch receptors in the lungs?

CN X Signup and view all the answers

What is primarily prevented by the Hering-Breuer Reflex during inhalation?

Over-inflation of the lungs Signup and view all the answers

What differentiates conducting airways from respiratory airways?

Conducting airways do not participate in gas exchange Signup and view all the answers

Which part of the airway system includes structures primarily involved in gas exchange?

Alveoli Signup and view all the answers

How does hypoxemia influence medullary activity?

It stimulates an increase in breathing rate Signup and view all the answers

What is a key function of pseudostratified ciliated columnar epithelium in the respiratory tract?

Movement of mucus across its surface Signup and view all the answers

Which of the following structures is part of the conducting airways?

Terminal bronchioles Signup and view all the answers

What is the primary reason premature infants are at an increased risk for respiratory distress syndrome?

Premature infants have insufficient production of surfactant, which helps keep alveoli open. Signup and view all the answers

According to the oxygen cascade, which of the following represents the approximate partial pressure of oxygen in the alveoli?

120 mmHg Signup and view all the answers

What is the primary effect of increasing the partial pressure of oxygen in a patient's blood?

Increases the rate of diffusion of oxygen into the blood. Signup and view all the answers

Which of the following is NOT a direct factor contributing to the regulation of breathing rate by the medulla?

Body temperature Signup and view all the answers

How does the diaphragm contribute to the process of inspiration (breathing in) according to Boyle's Law?

The diaphragm contracts, increasing the volume of the thoracic cavity and decreasing pressure. Signup and view all the answers

Which of the following conditions would have the most profound effect on breathing rate, as monitored by the medulla?

Hypercapnea (high CO2 levels) Signup and view all the answers

Why does the partial pressure of oxygen decrease as air is inhaled?

The air is warmed and humidified by the respiratory tract, diluting the oxygen concentration. Signup and view all the answers

What is the relationship between vital capacity (VC) and the movement of air during breathing?

VC represents the maximum volume of air that can be moved in and out of the lungs in one breath. Signup and view all the answers

What is the primary physiological mechanism responsible for compensating for the decreased partial pressure of oxygen at high altitude?

Hypoxemic drive Signup and view all the answers

What is the primary role of the phrenic nerve in the neural control of breathing?

To regulate the diaphragm Signup and view all the answers

What happens to the pressure inside the lungs when the volume of the lungs increases, according to Boyle's Law?

The pressure decreases Signup and view all the answers

What is the primary effect of LaPlace's Law on alveolar air pressure?

It increases alveolar air pressure in smaller alveoli Signup and view all the answers

What happens to the concentration of oxygen in the lungs when a person breathes in room air?

It decreases due to dilution by H2O and mixing with residual air Signup and view all the answers

What reflex primarily controls pontine breathing?

Hering-Breuer Reflex Signup and view all the answers

Study Notes

Cellular Roles in the Lungs

Type I Pneumocyte: responsible for diffusion of gases
Type II Pneumocyte: produces surfactant
Pseudostratified Ciliated Columnar Epithelium: facilitates movement of mucous

Spirogram Basics

Pontine breathing: represented by TV (tidal volume)
Overall lung function: best indicated by FVC (forced vital capacity)
Air left in lungs after normal exhalation: FRC (functional residual capacity)
Modern way to assess vital capacity: FEV6 (forced expiratory volume in 6 seconds)

Anatomic Structures in the Lungs

Conducting airways: Trachea, Bronchi, Large, Small & Terminal Bronchioles
Respiratory airways: Respiratory Bronchioles, Alveolar Ducts, Alveoli

Muscles and Nerves Involved in Breathing

Main muscle for breathing: Diaphragm
Type of muscle: Skeletal
Nerve controlling the Diaphragm: Phrenic nerve

Oxygen Therapy and Henry's Law

Increased ppO2 leads to increased diffusion of O2, which leads to increased PO2
Relying on Henry's Law, which states that the amount of dissolved gas in a liquid is directly proportional to the pressure of the gas

Medulla's Role in Breathing Rate

At high altitude: medulla senses low O2, increasing breathing rate to compensate (Hypoxemic Drive)
During exercise: medulla senses high CO2 levels, increasing breathing rate to remove CO2 (Hypercapnic Drive)

Boyle's Law and Breathing

To breathe in: increase volume, decrease pressure
To breathe out: decrease volume, increase pressure

LaPlace's Law and Alveolar Air Pressure

True: alveolar air pressure is inversely related to the size of the alveoli
Pulmonary surfactant decreases air pressure by decreasing surface tension

Neural Control of Breathing

Vagus/CN X nerve controls the vocal cords
Hering-Breuer Reflex controls pontine breathing
CN IX and X (Glossopharyngeal and Vagus) nerves send information to the medulla regarding CO2, H+, and O2 levels in the blood

Factors Affecting Oxygen Concentration

Concentration of oxygen decreases as you breathe in room air due to dilution by H2O and mixing with residual air in the lungs

Respiratory System

Premature infants born before 32 weeks gestation are at risk for Respiratory Distress Syndrome due to the lack of surfactant production.
Without surfactant, smaller alveoli collapse, causing air to push into larger alveoli, leading to respiratory distress.
The Law of LaPlace explains this phenomenon.

Oxygen Cascade

The partial pressure of oxygen decreases as you breathe in due to water absorption in the respiratory tract, which dilutes oxygen concentration.
Inspired oxygen: 160 mmHg
Alveolar oxygen: ~120 mmHg
Oxygen in the blood: ~100 mmHg
Oxygen at tissue level: ~4-20 mmHg

Henry's Law

Delivering oxygen via mask or nasal cannula relies on Henry's Law, which states that increasing the partial pressure of a gas improves its diffusion.
Increasing oxygen partial pressure via nasal cannula increases diffusion, leading to increased PO2 in the blood.

Spirogram

Vital capacity (VC) is the maximum volume of air that can be moved in one breath.
A spirogram is a diagram that measures lung function.

Boyle's Law and Diaphragm Movement

The movement of the diaphragm during breathing exploits Boyle's Law, which states that volume and pressure are inversely proportional.

Control of Breathing Rate

Hypercapnea has the most profound effect on breathing rate.
The medulla receives information about CO2, H+, and O2 levels from receptors in the aorta and carotids via the ninth and tenth cranial nerves.
The medulla also directly samples CSF for CO2 and pH levels.

Pleura and Epithelium

The parietal pleura, visceral pleura, and pleural space fluid are connected.
Pseudostratified ciliated columnar epithelium is found in the posterior nasal passage, nasopharynx, and trachea, and serves to move mucous across its surface.

Nerves and Lungs

The phrenic nerve controls the diaphragm.
The vagus nerve (CN X) controls the vocal cords.

Conducting and Respiratory Airways

Conducting airways: trachea, bronchi, large, small, and terminal bronchioles.
Respiratory airways: respiratory bronchioles, alveolar ducts, alveoli.

Hering-Breuer Reflex

Stretch receptors in the lungs and chest wall monitor lung inflation and trigger exhalation and inhibit inspiration to prevent lung damage from over-inflation.

Lung Structure and Function

The apex, base, and hilum of a lung are important structures.
The hilum is the root of the lung, where blood vessels and bronchi enter and exit.
Type I pneumocytes are squamous cells allowing for enhanced diffusion, while type II pneumocytes are cuboidal cells that secrete pulmonary surfactant.

Bronchopulmonary Segments

A bronchopulmonary segment is an anatomical and functional subdivision of a lobe, supplied by its own tertiary bronchus, artery, vein, lymph vessels, and autonomic nerves.
There are typically 10 segments in both the right and left lung.

High Altitude and Emphysema

At high altitude, breathing rate and heart rate increase due to low oxygen levels.
This is similar to the physiological changes experienced by emphysemics, but unlike emphysemics, individuals at high altitude are not hypercapnic.

Exercise and Respiratory Response

During vigorous exercise, breathing rate and cardiac output increase due to the stress of exercise, which stimulates the release of epinephrine, leading to increased heart rate and stroke volume via beta-1 receptors.

Respiratory System

Type I Pneumocyte: responsible for diffusion of gases
Type II Pneumocyte: produces surfactant
Pseudostratified Ciliated Columnar Epithelium: facilitates movement of mucus
Tracheal C-ring: provides support to trachea and allows swallowing

Spirogram

Pontine breathing: represented by TV (tidal volume)
Overall lung function: best indicated by FVC (forced vital capacity)
FRC (functional residual capacity): volume of air left in lungs after normal exhalation
FEV6: modern way to assess vital capacity

Anatomic Structures

Conducting airways: include trachea, bronchi, large, small, and terminal bronchioles
Respiratory airways: include respiratory bronchioles, alveolar ducts, and alveoli

Breathing Mechanics

Main muscle for breathing: diaphragm, which is a skeletal muscle
Nerve controlling diaphragm: phrenic nerve

Oxygen Therapy

Oxygen therapy: increases ppO2, leading to increased diffusion of O2 and increased PO2
Henry's Law: relates to the increase in oxygen diffusion

Respiratory Control

Medulla's role in hypoxemic drive: senses low O2 in blood, increasing breathing rate to compensate
Medulla's role in hypercapnic drive: senses high CO2 levels in blood, increasing breathing rate to remove CO2

Gas Laws

Boyle's Law: relates to breathing in (increasing volume, decreasing pressure) and breathing out (decreasing volume, increasing pressure)
Laplace's Law: alveolar air pressure is inversely related to the size of the alveoli
Pulmonary surfactant: decreases air pressure by decreasing surface tension

Neural Control

Nerve controlling vocal cords: vagus/CN X
Hering-Breuer Reflex: controls pontine breathing
CN IX and X: send information to medulla regarding CO2, H+, and O2 levels in the blood

Oxygen Concentration

Decrease in oxygen concentration: due to dilution by H2O and mixing with residual air in the lungs

Pontine Breathing

Definition and Characteristics

Pontine breathing is a type of abnormal breathing pattern characterized by rapid, shallow breaths
Rapid rate: 60-100 breaths per minute (normal rate: 12-20 breaths per minute)
Shallow depth: Limited chest expansion and minimal diaphragmatic movement
Irregular rhythm: Breaths can be irregular, with varying intervals between breaths

Causes of Pontine Breathing

Brainstem injury: Damage to the pons, a part of the brainstem that regulates breathing
Cerebral hemorrhage: Bleeding in the brain, which can compress the brainstem
Trauma: Head or neck trauma that affects the brainstem
Infections: Meningitis, encephalitis, or other infections that affect the brainstem

Clinical Significance of Pontine Breathing

Indicates brainstem dysfunction: Pontine breathing is a sign of severe brainstem injury or compression
Poor prognosis: Often associated with poor neurological outcomes or death
Monitoring: Close monitoring of respiratory and neurological status is essential

Management of Pontine Breathing

Supportive care: Maintain airway, breathing, and circulation (ABCs)
Mechanical ventilation: May be necessary to support breathing
Neurological monitoring: Close monitoring of neurological status and brainstem function

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Description

This practice exam tests knowledge on the respiratory system, including cell types and their roles, and spirometry concepts.