Respiratory System & Comparative Respiration

A set of vocabulary flashcards covering the human respiratory system, breathing mechanics, and comparative respiration in other animals.

Respiratory System

Body system responsible for the exchange of oxygen and carbon dioxide between an organism and its environment.

Respiration (Physiological)

Process of taking in oxygen from the environment, delivering it to cells, and removing carbon dioxide produced by cellular respiration.

Breathing

Physical act of inhalation and exhalation in which oxygen is drawn in and carbon dioxide is expelled.

Cellular Respiration

Metabolic breakdown of glucose in cells to release energy, producing carbon dioxide as a by-product.

Pulmonary Ventilation

Movement of air into and out of the lungs; another term for breathing.

Upper Respiratory Tract

Portion of the respiratory system including the nasal cavity, pharynx, and larynx.

Lower Respiratory Tract

Portion of the respiratory system consisting of the trachea, bronchi, bronchioles, and lungs.

Nasal Cavity

First entry chamber for inhaled air; divided into vestibule, respiratory, and olfactory regions.

Vestibule Region (Nose)

Anterior part of the nasal cavity lined with mucus that traps microorganisms and debris.

Respiratory Region (Nose)

Middle section of the nasal cavity that warms and moistens incoming air to near body temperature (37 °C).

Olfactory Region

Posterior nasal area containing sensory cells for the sense of smell.

Pharynx

Muscular throat cavity acting as a common chamber for air and food; divided into nasopharynx, oropharynx, and laryngopharynx.

Nasopharynx

Upper portion of the pharynx located behind the nasal cavity; passageway solely for air.

Oropharynx

Middle portion of the pharynx behind the oral cavity; pathway for both air and swallowed food.

Laryngopharynx

Lower portion of the pharynx that directs air toward the trachea and food toward the esophagus.

Epiglottis

Flap-like structure that covers the larynx during swallowing to prevent food or liquid from entering the trachea.

Larynx

Voice box; opens for breathing and closes to produce sound via vibrating vocal cords.

Trachea

Windpipe located below the larynx; supported by C-shaped rings of hyaline cartilage for strength and flexibility.

Bronchi

Two primary branches of the trachea that serve as entry points of air into each lung.

Bronchioles

Progressively smaller airway branches of the bronchi that end at the alveoli.

Alveoli

Grape-like air sacs at the tips of bronchioles where gas exchange with blood occurs.

Rib Cage

Bony structure composed of ribs, sternum, and vertebrae that protects the lungs and expands during inhalation.

Diaphragm

Dome-shaped muscle that contracts downward during inhalation and relaxes upward during exhalation.

Direct Diffusion

Gas exchange across the body surface without specialized respiratory organs, seen in bacteria, archaea, and small protists.

Cutaneous Respiration

Gas exchange across moist, vascularized skin, utilized by amphibians like frogs and salamanders.

Gills

Highly vascular respiratory organs in fish; gill filaments and lamellae provide large surface area for aquatic gas exchange.

Countercurrent Exchange

Efficient transfer mechanism where two fluids flow in opposite directions, maximizing diffusion (e.g., water and blood in fish gills).

Concurrent Exchange

Transfer mechanism where two fluids flow in the same direction, resulting in less efficient diffusion compared to countercurrent flow.

Tracheal System (Insects)

Network of air-filled tubes that delivers oxygen directly to insect tissues without circulatory assistance.

Spiracles

External openings on an insect’s exoskeleton through which air enters the tracheal system.

Tracheoles

Fine terminal branches of an insect’s tracheal tubes located adjacent to body cells for direct gas exchange.

Air Sacs (Insects)

Enlarged portions of the trachea that store large volumes of air to meet high oxygen demands.

Hyaline Cartilage

Type of connective tissue forming C-shaped rings that support the trachea.

C-shaped Cartilage Ring

Incomplete ring of cartilage in the trachea that provides rigidity while allowing esophageal expansion.

Respiratory System

Body system for exchanging oxygen and carbon dioxide.

Respiration (Physiological)

Process of taking oxygen, delivering it to cells, and removing carbon dioxide.

Breathing

Physical act of inhaling oxygen and exhaling carbon dioxide.

Cellular Respiration

Metabolic breakdown of glucose for energy, producing carbon dioxide.

Pulmonary Ventilation

Movement of air into and out of the lungs; breathing.

Upper Respiratory Tract

Nasal cavity, pharynx, and larynx.

Lower Respiratory Tract

Trachea, bronchi, bronchioles, and lungs.

Nasal Cavity

First chamber for inhaled air, divided into vestibule, respiratory, and olfactory regions.

Vestibule Region (Nose)

Anterior nasal cavity; traps microorganisms.

Respiratory Region (Nose)

Middle nasal cavity; warms and moistens incoming air.

Olfactory Region

Posterior nasal area with sensory cells for smell.

Pharynx

Throat cavity for air and food; nasopharynx, oropharynx, and laryngopharynx.

Nasopharynx

Upper pharynx; air passage only.

Oropharynx

Middle pharynx; pathway for air and food.

Laryngopharynx

Lower pharynx; directs air to trachea and food to esophagus.

Epiglottis

Flap covering the larynx during swallowing to prevent food/liquid in trachea.

Larynx

Voice box; opens for breathing, closes for sound via vocal cords.

Trachea

Windpipe below larynx; supported by C-shaped cartilage rings.

Bronchi

Two major branches of trachea entering each lung.

Bronchioles

Smaller airway branches of bronchi ending at alveoli.

Alveoli

Grape-like air sacs where gas exchange with blood occurs.

Rib Cage

Bony structure (ribs, sternum, vertebrae) protecting lungs and expanding during inhalation.

Diaphragm

Dome-shaped muscle; contracts downward during inhalation, relaxes upward during exhalation.

Direct Diffusion

Gas exchange across body surface without specialized organs (e.g., bacteria, small protists).

Cutaneous Respiration

Gas exchange across moist, vascularized skin (e.g., amphibians).

Gills

Highly vascular respiratory organs in fish for aquatic gas exchange.

Countercurrent Exchange

Efficient transfer where two fluids flow in opposite directions, maximizing diffusion (e.g., fish gills).

Concurrent Exchange

Transfer where two fluids flow in the same direction, less efficient than countercurrent flow.

Tracheal System (Insects)

Network of air-filled tubes delivering oxygen directly to insect tissues.

Spiracles

External openings on insect exoskeleton for air entry into tracheal system.

Tracheoles

Fine terminal branches of insect tracheal tubes for direct gas exchange with cells.

Air Sacs (Insects)

Enlarged tracheal portions in insects storing air for high oxygen demands.

Hyaline Cartilage

Connective tissue forming C-shaped rings supporting the trachea.

Incomplete cartilage ring in trachea, providing rigidity while allowing