Respiratory System Structures

Questions and Answers

What is the function of the fissure in the lung?

It separates the lung into different lobes (correct)

It participates in gas exchange

It produces surfactant

It prevents the lung from collapsing

What is the portion of the lung that contains alveoli and participates in gas exchange?

Lung parenchyma (correct)

Terminal bronchiole

Lobule of the lung

Alveolar duct

What is the main function of type I alveolar cells?

Gas exchange (correct)

Regulation of blood pressure

Production of surfactant

Secretion of alveolar fluid

What is the function of surfactant?

Prevent the lung from collapsing Signup and view all the answers

What is the structure that wraps around the lobule of the lung?

Elastic connective tissue Signup and view all the answers

What is the function of the nasopharynx in relation to the auditory tubes?

To equalize air pressure between the middle ear and the atmosphere Signup and view all the answers

What is the name of the cells that secrete alveolar fluid, including surfactant?

Type II alveolar cells Signup and view all the answers

How many lobes does the right lung have?

3 Signup and view all the answers

What type of epithelium lines the wall of the oropharynx?

Nonkeratinized stratified squamous epithelium Signup and view all the answers

What is the name of the structure at the end of the bronchioles?

Alveolus Signup and view all the answers

At which level does the laryngopharynx begin?

At the level of the hyoid bone Signup and view all the answers

What is the function of the pharynx in relation to speech?

To promote resonating chamber for speech sounds Signup and view all the answers

What is the location of the larynx in the neck?

Anterior to the esophagus and the fourth through sixth cervical vertebrae Signup and view all the answers

What type of epithelium lines the wall of the larynx superior to the vocal fold?

Nonkeratinized stratified squamous epithelium Signup and view all the answers

What is the alternative name for the trachea?

Windpipe Signup and view all the answers

What is the function of the tonsils in the pharynx?

To participate in immunological reactions against foreign invasion Signup and view all the answers

What percentage of oxygen from the lung is transported in combination with hemoglobin?

97% Signup and view all the answers

What is the result of an increase in blood oxygen partial pressure on the oxygen-hemoglobin dissociation curve?

A progressive increase in the percentage of hemoglobin bound with oxygen Signup and view all the answers

What is the effect of carbon dioxide and hydrogen ions on the oxygen dissociation curve?

Shift the curve to the right Signup and view all the answers

What is the approximate amount of oxygen that 100ml of human blood can carry?

20.1ml Signup and view all the answers

What is the amount of oxygen released to tissues in normal state?

5ml Signup and view all the answers

What is the effect of carbon monoxide on oxygen carrying capacity of hemoglobin?

Decreases the oxygen carrying capacity Signup and view all the answers

What is the composition of hemoglobin?

2 alpha and 2 beta chains Signup and view all the answers

What is the approximate factor by which oxygen release to tissues can increase during strenuous exercise?

3 Signup and view all the answers

What is the primary direction of gas movement related to concentration?

From high concentration to low concentration Signup and view all the answers

What does the solubility coefficient represent?

Volume of gas dissolved per partial pressure Signup and view all the answers

According to Henry's law, which of the following is true?

Partial pressure is equal to solubility and concentration Signup and view all the answers

How is the partial pressure of oxygen at sea level calculated if the concentration of oxygen is 21%?

160 mmHg Signup and view all the answers

Which gas has a solubility coefficient of 0.57?

Carbon dioxide Signup and view all the answers

What does the term 'partial pressure' refer to?

Pressure exerted by a single gas in a mixture Signup and view all the answers

What determines the partial pressure of dissolved gases?

Concentration and solubility coefficient Signup and view all the answers

Which of the following gases has a solubility coefficient of 0.024?

Oxygen Signup and view all the answers

What does the diffusion coefficient of a gas represent?

The solubility of the gas in the membrane Signup and view all the answers

Which factor increases the diffusion rate of gases through the respiratory membrane?

Increased surface area Signup and view all the answers

What is a common cause of decreased diffusion through the respiratory membrane?

Emphysema Signup and view all the answers

How is the diffusion capacity of a gas through the respiratory membrane measured?

Volume per minute for a partial pressure difference of 1 mmHg Signup and view all the answers

What happens to gas diffusion when the membrane thickness increases?

Decreases diffusion rate Signup and view all the answers

Which of the following is NOT a factor that determines gas diffusion through the respiratory membrane?

Presence of oxygen in the air Signup and view all the answers

What is the normal diffusion capacity of oxygen in a resting man?

21 ml/min/mm Hg Signup and view all the answers

Which condition is likely to increase the thickness of the respiratory membrane?

Pulmonary fibrosis Signup and view all the answers

Study Notes

Structures of the Respiratory System

Nasopharynx: Located behind the nasal cavity, extends to the soft palate, lined with pseudostratified ciliated columnar epithelium, facilitates equalization of air pressure between the middle ear and atmosphere via auditory tubes.
Oropharynx: Serves both respiratory and digestive purposes, acts as a passage for air, food, and fluid, lined with nonkeratinized stratified squamous epithelium for abrasion protection.
Laryngopharynx: Begins at the hyoid bone, opens to the esophagus and larynx, lined with nonkeratinized stratified squamous epithelium, facilitates air and food passage, acts as a resonating chamber for speech, houses tonsils for immune response.
Larynx (Voice Box): Connects the laryngopharynx to the trachea, located anterior to the esophagus, has varying epithelial linings: nonkeratinized stratified squamous epithelium above vocal folds and pseudostratified ciliated columnar epithelium below.
Trachea (Windpipe): Extends inferiorly from the larynx and divides the lungs into lobes, also features a right horizontal fissure that creates a middle lobe.
Lung Parenchyma: Portion responsible for gas exchange, contains alveoli that open into alveolar ducts, crucial for respiratory function.
Lobule of the Lung: Small compartments within bronchopulmonary segments, wrapped in elastic connective tissue, includes lymphatic vessels, arterioles, venules, and branches from terminal bronchioles.

Alveoli

Alveolus: Cup-shaped sac at the bronchiole's end, main site for gas exchange, lined with two types of alveolar epithelial cells.
Type I Alveolar Cells: Predominant in number, squamous cells forming a continuous lining for gas exchange.
Type II Alveolar Cells: Fewer in number, secrete alveolar fluid and surfactant to maintain alveolar stability by lowering surface tension.

Gas Exchange Principles

Partial Pressure: Concentration of gas in a mixture is proportional to its pressure, with gases diffusing from areas of higher to lower concentration.
Concentration of Oxygen at Sea Level: The partial pressure of oxygen (21% of 760 mmHg) equals 160 mmHg.
Henry’s Law: The relationship between partial pressure and solubility of gases, critical for understanding gas behavior in solutions.

Factors Affecting Gas Diffusion

Thickness of Respiratory Membrane: Increased thickness reduces diffusion efficiency, commonly caused by ailments like edema or pulmonary fibrosis.
Surface Area of Respiratory Membrane: Reduced surface area decreases diffusion, for example, due to removal of lung tissue or conditions like emphysema.
Diffusion Coefficient: Indicator of diffusion rate, influenced by gas solubility and molecular weight.

Diffusion Capacity

Diffusion Capacity: Volume of gas diffusing through the membrane per minute for a partial pressure difference of 1 mmHg. Normal oxygen diffusion capacity at rest is 21 ml/min/mmHg.

Hemoglobin and Oxygen Transport

Oxygen Transportation: 97% of oxygen binds to hemoglobin (Hb) for transport; remaining 3% is dissolved in plasma.
Hemoglobin Structure: Comprises 4 polypeptide chains (2 alpha, 2 beta), each with a heme group capable of binding oxygen.
Oxygen-Carrying Capacity: A typical 100 ml blood contains 15 g of hemoglobin, allowing for an oxygen capacity of 20.1 ml, with approximately 5 ml released to tissues under normal conditions.

Oxygen-Hemoglobin Dissociation Curve

Dissociation Curve: Reflects hemoglobin's oxygen saturation levels rising with increased blood oxygen partial pressure.
Bohr Effect: An increase in carbon dioxide and hydrogen ions shifts the dissociation curve to the right, facilitating oxygen release to tissues.
Carbon Monoxide Binding: CO competes with oxygen for hemoglobin binding sites with a much higher affinity, critically affecting oxygen transport efficiency.

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Description

This quiz covers the different structures of the respiratory system, including the nasopharynx, oropharynx, and laryngopharynx. Learn about their functions and characteristics.