The Respiratory System: Structures and Functions

Comprehensive flashcards covering the anatomy and physiology of the upper and lower respiratory systems, including gas exchange, lung volumes, and respiratory control.

What are the two primary functions of the respiratory system?

The respiratory system exchanges gases ($oxygen$ and $CO_2$) and protects the body from airborne irritants.

Which major organs are included in the respiratory system?

Nasal cavities, Larynx, Pharynx, Trachea, and Lungs.

How does the nasal cavity process incoming air?

The nasal cavity is lined with mucosa that warms the incoming air and traps foreign objects, while ciliated cells propel debris toward the throat for digestion.

What is the function of the three ridges called conchae within the nasal cavity?

They increase the mucosal surface area and air turbulence, allowing more particulates to contact the walls instead of entering the lungs.

How do the hard and soft palates differ in composition?

The hard palate is made of bone, while the soft palate is made of muscle.

What are the three main functions of the paranasal sinuses?

To lighten the skull, resonate speech, and produce mucus.

What term describes the inflammation of the sinus spaces?

Rhinitis.

Into which three regions is the pharynx divided?

Nasopharynx (nasal portion), Oropharynx (oral portion), and Laryngopharynx (opening of larynx and esophagus).

What are the three types of lymphatic tissue clusters (tonsils) found in the pharynx?

Pharyngeal tonsil (adenoid), 2 palatine tonsils, and 2 lingual tonsils.

What are the three primary functions of the larynx (the voice box)?

Provide an open airway via cartilage, divert air and food into proper pathways via the epiglottis, and produce sound via vocal cords.

Which two pieces of hyaline cartilage in the larynx are the largest?

Thyroid cartilage (which makes up the Adam’s apple) and Cricoid cartilage (which attaches the larynx to the trachea).

How does the epiglottis function during eating?

The epiglottis tips to cover the larynx, directing food through the esophagus rather than into the lungs.

Which factors contribute to the variation in sound produced by the vocal cords?

Volume (amount of air), Pitch (tension and thickness of the cords), and Articulation (use of tongue, lips, mouth, and teeth).

What is the physical structure of the trachea?

The trachea is a rigid tube about $5\,inches$ long surrounded by horseshoe-shaped cartilaginous rings that are open posteriorly.

What happens to the trachea just behind the heart?

The trachea divides into 2 bronchi, which then branch into smaller tubes called bronchioles.

What is the purpose of the pleural fluid found in the pleura membrane?

It reduces friction between the lungs and the rest of the thoracic cavity.

How do the right and left lungs differ structurally?

The right lung has 3 lobes, while the left lung has 2 lobes and an indentation for the heart called the cardiac notch.

What structures compose the respiratory zone where gas exchange occurs?

The thin-walled alveoli and the surrounding capillaries.

What is the difference between external and internal respiration?

External respiration is gas exchange between pulmonary blood vessels and the alveoli (in the lungs), while internal respiration is gas exchange between blood and body tissues (throughout the body).

How do the diaphragm and external intercostals cause inhalation?

By contracting, they expand the rib cage and decrease the pressure inside the lungs, causing air to rush in (inspiration).

What is the definition of Tidal volume?

The amount of air that is exchanged by the lungs at rest.

What is the difference between Vital capacity and Total lung capacity?

Vital capacity is the air one can consciously exchange, while Total lung capacity is Vital capacity plus Residual volume ($6\,liters$ for adult men, $10\%$ less for females).

Which part of the brain contains the respiratory control centers?

The brainstem, specifically the medulla and the pons.

What is the relationship between the Ventral Respiratory Group (VRG) and the Dorsal Respiratory Group (DRG)?

The VRG controls neurons for quiet, regular breathing, while the DRG collects sensory information and passes it to the VRG.

What is identified as the most important chemical stimulus for breathing?

The level of $CO_2$ (carbon dioxide) in the blood.

Where are the chemoreceptors located that recognize changes in blood pH or $CO_2$ concentration?

In the aorta and the common carotid artery.