Respiratory System

What is ventilation?

The movement of air in and out of the lungs (breathing).

What is respiration?

The diffusion of gases across the cell membrane.

What is external respiration?

The movement of gases between the atmospheric air in the lungs and blood.

What is internal respiration?

The movement of gases between the blood and the body's cells after inhalation.

What are the organs of the respiratory system?

External nose, nasal cavity, pharynx, larynx, trachea, bronchi, and lungs.

What makes up the upper respiratory tract?

The nose, pharynx, and larynx.

What makes up the lower respiratory tract?

The trachea, bronchi, and lungs.

What is the conducting zone?

The pathway from the nose to the smallest air tubes for ventilation; it is responsible for air passage.

What is the respiratory zone?

The area within the lungs and small air tubes and alveoli where gas exchange occurs.

What is the primary function of the respiratory system?

Gas exchange of oxygen (O2) and carbon dioxide (CO2).

How does the respiratory system regulate blood pH?

By altering blood CO2 levels, which can affect the acidity of the blood.

What chemical mediator does the respiratory system produce?

Angiotensin converting enzyme (ACE).

What role does the respiratory system play in voice production?

Air movement past the vocal cords produces sound and enables speech.

What is olfaction?

The sensation of smell, facilitated by the respiratory system.

How does the respiratory system provide protection?

Through innate immunity mechanisms like mucus and cilia.

What is the external nose?

The visible structure that forms a prominent feature of the face.

What is the composition of the external nose?

Most of it is composed of hyaline cartilage, while the bridge consists of bone (nasal bone).

What are the nares?

The nostrils; the external openings of the nose.

What is the nasal cavity?

The space that extends from the nares (external openings) to the choanae.

What is the vestibule?

The area just inside the nostrils; it is the initial entry point for air.

What are choanae?

The openings that connect the nasal cavity to the pharynx.

What is the nasal septum?

A partition that divides the nasal cavity into right and left parts (center).

What is the hard palate?

The structure that forms the floor of the nasal cavity, separating it from the oral cavity (composed of the maxilla and palatine bone).

What are conchae?

Three prominent bony ridges on the lateral walls of each side of the nasal cavity that aid in cleaning and humidifying air (superior, middle, inferior).

What is a meatus?

The space between the conchae (superior, middle, inferior).

What do the nasolacrimal ducts do?

They carry tears from the eyes into the nasal cavity.

What type of epithelium is found inside the nares?

Stratified squamous epithelium containing coarse hairs.

What lines the rest of the nasal cavity?

Pseudostratified columnar epithelial cells containing cilia and many mucus-producing goblet cells.

What is the function of the coarse hairs in the nares?

They trap large dust particles.

How does mucus in the nasal cavity help the air?

Mucus humidifies the air and traps debris and pathogens.

What happens to debris-laden mucus in the nasal cavity?

Cilia sweep it toward the pharynx, where it is swallowed and neutralized by stomach acid.

What is the pharynx?

A common passageway for both the respiratory and digestive systems.

What passes through the pharynx?

Air from the nasal cavity, and food and water from the mouth.

How does the pharynx connect to the respiratory and digestive systems?

It leads to the larynx (respiratory) and the esophagus (digestive) inferiorly.

Into what three parts is the pharynx divided?

Nasopharynx, oropharynx, and laryngopharynx.

Where is the nasopharynx located?

It is located posterior to the choanae and superior to the soft palate.

What happens to the soft palate during swallowing?

It elevates to close the nasopharynx and prevent food from passing into it from the oral cavity.

What type of epithelium lines the nasopharynx?

Pseudostratified ciliated columnar epithelium that is continuous with the nasal cavity.

What do the auditory tubes do in the nasopharynx?

They extend from the middle ears and open into the nasopharynx.

What tonsils are located in the nasopharynx?

The pharyngeal tonsils, located on the posterior part of the nasopharynx.

What is the location of the oropharynx?

It extends from the uvula to the epiglottis and is the passage where the oral cavity opens.

What type of epithelium lines the oropharynx?

Stratified squamous epithelium, which provides protection.

Where are the palatine tonsils located?

In the lateral walls near the border of the oral cavity and the oropharynx.

Where is the lingual tonsil located?

On the surface of the posterior part of the tongue.

What is the location of the laryngopharynx?

It passes posterior to the larynx and extends from the tip of the epiglottis to the esophagus.

What passes through the laryngopharynx?

Food and drink pass through to the esophagus.

What happens to air during swallowing?

A small amount of air is usually swallowed with food and drinks.

What type of epithelium lines the laryngopharynx?

Lined with stratified squamous epithelium and ciliated columnar epithelium.

What is the larynx commonly known as?

The voice box.

Where is the larynx located?

Anterior throat; it extends from the base of the tongue to the trachea.

What are the three main functions of the larynx?

Maintains an open airway, protects the airway during swallowing, and produces voice.

How many cartilage structures are in the larynx?

Nine cartilage structures: three paired and three unpaired.

What are the unpaired cartilages of the larynx?

Thyroid cartilage, cricoid cartilage, and epiglottis.

What is the thyroid cartilage also known as?

The Adam's apple; it is attached superiorly to the hyoid bone.

What is the cricoid cartilage?

The ring-shaped cartilage that is the most inferior and forms the base of the larynx.

What is the role of the epiglottis?

Protects the airway during swallowing by covering the glottis.

What are the paired cartilages of the larynx?

Cuneiform (wedge-shaped), corniculate (horn-shaped), and arytenoid (ladle-shaped).

What is the function of the arytenoid cartilage?

It articulates with the cricoid inferiorly and forms an attachment site for the vocal folds.

What are the false vocal cords?

The superior set of ligaments that form the vestibular folds; they prevent air from leaving the lungs and block food and liquids from entering the larynx.

What are the true vocal cords?

The inferior set of ligaments that compose the vocal folds; they are the primary source of voice production.

How is sound produced by the vocal cords?

Air moving past the vocal folds causes them to vibrate, producing sound.

What controls the length and tension of the vocal folds?

Muscles control the length and tension of the vocal folds.

How does the force of air affect voice production?

The force of air moving past the vocal folds controls the loudness of the sound.

How does the tension of the vocal folds affect voice?

The tension of the vocal folds controls the pitch of the voice.

What is the trachea commonly known as?

The windpipe.

What is the structure of the trachea?

A membranous tube approximately 10-11 cm long and 1.4 - 1.6 cm in diameter, lined with pseudostratified columnar epithelium containing cilia and goblet cells.

What supports the trachea structurally?

It has connective tissue and smooth muscle, reinforced with 16-20 C-shaped pieces of hyaline cartilage on the anterior and lateral sides, with an elastic membrane at the posterior.

Where does the trachea begin?

It begins immediately inferior to the cricoid cartilage.

At what vertebral level does the trachea divide into the primary bronchi?

At the level of the 5th thoracic vertebra.

What is the carina?

The inferior termination of the trachea that leads to the primary bronchi, located at the T4-T5 level.

What does the trachea divide into?

The left and right main bronchi (primary bronchi), each connecting to a lung.

How is the left main bronchus different from the right?

The left main bronchus is more horizontal because it is displaced by the heart.

Why do foreign objects typically lodge in the right main bronchus?

Because it is wider, shorter, more vertical, and more in direct line with the trachea than the left main bronchus.

What type of epithelium lines the bronchi?

Pseudostratified ciliated columnar epithelium.

What supports the bronchi structurally?

They are supported by C-shaped pieces of cartilage.

What are the lungs?

The principal organs of respiration.

Describe the shape and position of each lung.

Each lung is cone-shaped, with its base resting on the diaphragm and its apex extending about 1 inch (2.5 cm) above the first rib.

How many lobes does the right lung have?

The right lung has three lobes: superior, middle, and inferior, and two fissures: oblique and horizontal.

How many lobes does the left lung have?

The left lung has two lobes: superior and inferior, and one fissure: oblique.

What is the cardiac notch?

A depression in the left lung that accommodates the heart.

What are bronchopulmonary segments?

Each lobe is divided into segments separated by connective tissue septa, not visible as surface fissures.

Why can individual bronchopulmonary segments be surgically removed?

Major blood vessels and bronchi do not cross the septa, allowing for removal without affecting the rest of the lung.

How many bronchopulmonary segments are in the left lung?

There are 9 bronchopulmonary segments in the left lung.

How many bronchopulmonary segments are in the right lung?

There are 10 bronchopulmonary segments in the right lung.

What does the tracheobronchial tree consist of?

The main bronchi and many branches.

What do the main bronchi divide into?

They divide into lobar bronchi (secondary) that enter the respective lungs and conduct air to each lung lobe. There are 2 lobar bronchi in the left lung and 3 in the right lung.

What are segmental bronchi also known as?

Tertiary bronchi; they lead to the bronchopulmonary segments of the lungs.

How many segmental bronchi are in the right lung?

There are 10 tertiary bronchi in the right lung.

How many segmental bronchi are in the left lung?

There are 9 tertiary bronchi in the left lung.

What do bronchioles give rise to?

Bronchioles continue to branch many times, leading to terminal bronchioles.

What do terminal bronchioles subdivide into?

They subdivide into respiratory bronchioles.

What do respiratory bronchioles form?

Each respiratory bronchiole subdivides to form alveolar ducts, which are long branching ducts with many openings into alveoli.

What are alveoli?

Small air-filled chambers where air and blood come into close contact with each other.

What happens to the alveolar duct walls?

They become so numerous that the walls are little more than a succession of alveoli.

What do alveolar ducts end as?

They end as 2 or 3 alveolar sacs, which are chambers connected to two or more alveoli.

How many alveoli are in the lungs?

There are approximately 300 million alveoli.

What are Type 1 pneumocytes?

Simple squamous cells involved in gas exchange.

What are Type 2 pneumocytes?

Cells that produce surfactant, which reduces surface tension in the alveoli.

What is the respiratory membrane?

The thin membrane where gas exchange between air and blood takes place.

What forms the respiratory membrane?

It is formed by the walls of alveoli and the surrounding capillaries.