Biology Lecture 14: The Respiratory System

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Questions and Answers

What is the main function of the conduction zone?

Production of surfactant

Conducts air from the environment to the respiratory zone (correct)

Regulation of breathing rate

Exchange of gases between the blood and the lungs

What is the function of type II alveolar cells?

Production of mucus

Allows for gas diffusion

Phagocytosis of foreign particles

Secretes surfactant (correct)

What is the result of pulmonary edema?

Blockage of pulmonary blood vessels

Accumulation of fluid in the pleural cavity

Inflammation of the bronchi

Accumulation of fluid in the lungs (in interstitial spaces and alveoli) (correct)

What is the function of the parietal pleural membrane?

Attached to the inner thoracic wall, diaphragm and mediastinum Signup and view all the answers

What is the result of emphysema?

Breakdown of the alveolar walls Signup and view all the answers

What is the primary function of the respiratory zone?

Responsible for the exchange of gases between the blood and the lungs Signup and view all the answers

What is the result of tuberculosis?

Thickening of the respiratory membrane Signup and view all the answers

What is the function of alveolar macrophages?

Moves across the surface of type I cells, removing foreign matter Signup and view all the answers

What is the result of pneumothorax?

Entry of air into the pleural cavity Signup and view all the answers

What is the function of the visceral pleural membrane?

Covers the surface of the lung Signup and view all the answers

What is the term for the inflammation of the vocal cords?

Laryngitis Signup and view all the answers

What is the primary function of the respiratory system?

To facilitate the exchange of gases between the lungs and the blood Signup and view all the answers

What is the function of the true vocal cords?

To produce sound Signup and view all the answers

What is the glottis?

The opening between the vocal cords Signup and view all the answers

Which part of the nasal cavity is lined with skin and has coarse hair?

Vestibule Signup and view all the answers

What is the function of the nasal conchae and meatuses?

To increase surface area and warm and moisten incoming air Signup and view all the answers

What is the structure of the trachea?

20 C-shaped pieces of hyaline cartilage Signup and view all the answers

Which bone contains two paranasal sinuses?

Frontal bone Signup and view all the answers

What is the function of the primary bronchi?

To connect the trachea to the lungs Signup and view all the answers

What is the function of the pharyngeal tonsil?

To aid in the immune response to infection Signup and view all the answers

What is the total number of lobar bronchi in the bronchial tree?

5 Signup and view all the answers

Which part of the larynx covers the glottis during swallowing?

Epiglottis Signup and view all the answers

What is the function of the ciliated pseudostratified epithelial cells in the respiratory system?

To move mucus and debris out of the respiratory system Signup and view all the answers

Which part of the respiratory system is responsible for the sense of smell?

Olfactory area Signup and view all the answers

What is the function of the lacrimal duct in the nasal cavity?

To drain tears into the nasal cavity Signup and view all the answers

Which part of the respiratory system serves as a passageway for both food and air?

Pharynx Signup and view all the answers

Study Notes

Roles of Respiratory System

The respiratory system moves air into and out of the lungs, facilitates exchange of gases (O2/CO2) between the lungs and the blood, and regulates blood pH.
It also plays a role in speaking and the sense of olfaction/smell.

Structure of Respiratory System

The respiratory system is divided into two subdivisions: the upper respiratory system and the lower respiratory system.
The upper respiratory system consists of the nose, nasal cavity, and pharynx.
The lower respiratory system consists of the larynx, trachea, bronchial tree, and lungs.

Structure of Respiratory System (continued)

The majority of the respiratory passageway is lined with ciliated pseudostratified epithelial cells (with mucous-producing goblet cells).
The connective tissue layer is known as the lamina propria.

The Nose

The nose is composed of the nasal bones, cartilage, and connective and adipose tissue.
The nostrils are also known as the nares.

The Nasal Cavity

The nasal cavity is divided into two by the nasal septum.
The anterior region is lined with hyaline cartilage.
The posterior region is lined with different bones.
The nasal cavity warms and moistens incoming air, facilitates olfaction (sense of smell), and serves as a resonance chamber for speech.
The nasal cavity contains the nasal conchae and mucus membrane-lined meatuses (grooves), which increase surface area and cause incoming air to swirl.

The Nasal Cavity (continued)

The vestibule is the anterior region lined with skin containing coarse hair (stratified squamous epithelia).
The respiratory region is the posterior region lined with mucosa (ciliated pseudostratified epithelial cells).
The lacrimal duct drains into the nasal cavity below the inferior nasal conchae, and tears drain into the nasal cavity.

The Olfactory Area

The olfactory area is located in the roof of the nasal cavity.
It is involved in the sense of smell.
The olfactory area contains neurons that act as olfactory receptors.

The Paranasal Sinuses

The paranasal sinuses are eight air-filled spaces in the skull bones.
They open into the nasal cavity.
The paranasal sinuses serve to warm and moisten air, and lighten the skull.
There are two sinuses in each of the following bones: frontal, sphenoid, ethmoid, and maxillae.

The Pharynx

The pharynx extends from the internal nares to the top of the larynx.
It serves as a passageway for food and air, and as a resonating chamber.
The pharynx includes the nasopharynx, oropharynx, and laryngopharynx.

The Nasopharynx

The nasopharynx is located posterior to the nasal cavity/internal nares.
It contains the openings to the nasal apertures and the auditory/eustachian tubes.
It contains the pharyngeal tonsil (adenoid).

The Oropharynx

The oropharynx is located posterior to the oral cavity (between the soft palate and the top of the epiglottis).
It is lined with stratified squamous epithelial cells.
It is a passageway for air and food, and contains the palatine and lingual tonsils.

The Laryngopharynx

The laryngopharynx is located between the epiglottis and the opening of the larynx.
It is lined with stratified squamous epithelial cells.
It is a passageway for air and food.

The Larynx

The larynx is a passageway for air composed of nine pieces of cartilage (all except the epiglottis are composed of hyaline cartilage).
The thyroid cartilage forms the anterior wall and Adam's apple.
The cricoid cartilage forms a complete ring.
The epiglottis covers the glottis during swallowing and is composed of elastic cartilage.
The arytenoid cartilages are attached to the vocal cords.

The Vocal Cords

The vocal cords are two pairs of folds in the mucosa.
The vestibular folds are also known as the false vocal cords.
The true vocal cords produce sound and are located in an opening known as the glottis (covered by the epiglottis during swallowing).
Inflammation of the vocal cords is known as laryngitis.

The Trachea

The trachea connects the larynx to the main bronchi.
It is located anterior to the esophagus.
It consists of 20 C-shaped pieces of hyaline cartilage (opening faces the esophagus).

The Bronchial Tree

The bronchial tree leads from the main bronchi to the alveolar ducts.
In the lower bronchi, cartilage is replaced by smooth muscle and elastic fibers.
There are two main bronchi, which are also known as primary bronchi.
Each main bronchus then splits into lobar bronchi.
The right lung has three lobar bronchi, and the left lung has two lobar bronchi.

The Lungs

The right and left lungs are separated by the mediastinum (containing the heart).
The right lung has three lobes: superior, middle, and inferior.
The left lung has two lobes: superior and inferior, and a cardiac notch where the heart is located.

The Pleural Membrane

Each lung is enclosed by its own double-layered pleural membrane.
The visceral pleural membrane covers the surface of the lung.
The parietal pleural membrane is attached to the inner thoracic wall, diaphragm, and mediastinum.
The pleural cavity contains pleural fluid, which reduces friction and holds the lungs to the walls of the thoracic cavity.

The Conduction Zone

The conduction zone is the region from the nasal cavity to the terminal bronchioles.
It conducts air from the environment to the respiratory zone.

The Respiratory Zone

The respiratory zone is the region from the respiratory bronchioles to the alveoli.
It is responsible for the exchange of gases (O2/CO2) between the blood and the lungs.

The Respiratory Membrane

The respiratory membrane consists of the walls of the alveoli and the blood vessels.
The walls of the blood vessels are composed of simple squamous epithelial cells and a basement membrane.
The walls of the alveoli are composed of type I and type II alveolar cells and a basement membrane.

The Respiratory Membrane (continued)

Type I alveolar cells are simple squamous epithelial cells that allow for gas diffusion.
Type II alveolar cells are simple cuboidal cells that secrete surfactant.
Surfactant decreases the surface tension of the alveolar fluid.
Alveolar macrophages move across the surface of type I cells, removing foreign matter.
Alveolar pores allow for air movement between the alveoli.

Blood Supply to the Lungs: Pulmonary Circulation

Deoxygenated blood is pumped from the right ventricle to the pulmonary trunk, then to the pulmonary arteries.
Blood is oxygenated in the respiratory capillaries in the lungs.
Oxygenated blood returns to the left atrium via the pulmonary veins.

Blood Supply to the Lungs: Systemic Circulation

Oxygenated blood is pumped from the left ventricle to the bronchial arteries.
Blood becomes deoxygenated as it passes through lung tissue.
Deoxygenated blood enters the bronchial veins and returns to the right atrium via the vena cava.

Clinical Applications

Pulmonary edema is the accumulation of fluid in the lungs (in interstitial spaces and alveoli), typically caused by heart failure (congestive heart failure).
Pneumonia is inflammation of the alveoli due to infection (bacterial or viral), resulting in damage to the alveoli and the accumulation of fluid.
Tuberculosis is caused by infection with the bacterium Mycobacterium tuberculosis, resulting in the thickening of the respiratory membrane and the replacement of lung tissue with fibrous connective tissue (scar tissue).
Pulmonary embolism is the blockage of pulmonary blood vessels, caused by blood clots, arteriosclerosis (hardening of the arteries), or air bubbles in the blood vessels.
Pneumothorax is the entry of air into the pleural cavity (between the lung and chest wall), which can be caused by injury or disease.
Emphysema is the breakdown of the alveolar walls, typically caused by smoking, air pollution, or the inhalation of chemical fumes or dust.

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Description

Learn about the roles and structure of the respiratory system, including the exchange of gases, regulation of blood pH, and the upper and lower respiratory systems.