Respiratory System

Part 1: Lecture Flashcards

What are the main functions of the respiratory system?

Ventilation, external respiration, gas transport, internal respiration, and cellular respiration.

What is ventilation?

Movement of air into and out of the lungs.

What is external respiration?

Exchange of O₂ and CO₂ between the alveoli and blood.

What is gas transport?

Movement of O₂ and CO₂ through the blood.

What is internal respiration?

Exchange of O₂ and CO₂ between the blood and body tissues.

What is cellular respiration?

Cells use O₂ to produce ATP and release CO₂ as waste.

How does the respiratory system regulate blood pH?

By changing CO₂ levels in the blood.

What enzyme do the lungs produce to help regulate blood pressure?

Angiotensin-converting enzyme (ACE).

What are the additional functions of the respiratory system?

Regulates blood pH, produces chemical mediators, produces voice, allows smell, and protects against pathogens.

What is the upper respiratory tract?

Structures from the nose through the larynx.

What is the lower respiratory tract?

Structures from the trachea through the alveoli.

What is the conducting zone?

Moves, warms, humidifies, and cleans air; no gas exchange occurs.

What is the respiratory zone?

Area where gas exchange occurs.

What is the correct order of the tracheobronchial tree?

Trachea → Primary bronchi → Secondary bronchi → Tertiary bronchi → Bronchioles → Terminal bronchioles → Respiratory bronchioles → Alveolar ducts → Alveolar sacs → Alveoli.

What are primary bronchi?

First branches of the trachea; one enters each lung.

What are secondary bronchi?

Branches that supply each lung lobe.

What are tertiary bronchi?

Branches that supply bronchopulmonary segments.

What are bronchioles?

Small airways that contain smooth muscle but no cartilage.

What are terminal bronchioles?

Last part of the conducting zone.

What are respiratory bronchioles?

First part of the respiratory zone; have alveoli attached.

What are alveolar ducts?

Small passages with openings into alveoli.

What are alveolar sacs?

Chambers containing groups of alveoli.

What are alveoli?

Tiny air sacs where gas exchange occurs.

What happens to cartilage as airways become smaller?

It becomes thinner and eventually disappears.

What happens to smooth muscle as airways become smaller?

Smooth muscle becomes a greater component of the airway wall.

How does the epithelium change as airways become smaller?

Changes from pseudostratified columnar to simple columnar, then simple cuboidal.

What is bronchodilation?

Smooth muscle relaxes, making the airway wider.

What is bronchoconstriction?

Smooth muscle contracts, making the airway narrower.

What happens during an asthma attack?

Bronchioles constrict, reducing airflow.

How is sound produced?

Air moves past the vocal folds, causing them to vibrate.

What determines the loudness of your voice?

Force of air moving past the vocal folds.

What determines the pitch of your voice?

Tension of the vocal folds.

What are vestibular folds?

False vocal cords located above the true vocal cords.

What is the glottis?

Opening between the true vocal folds.

What are the three main alveolar cell types?

Type I pneumocytes, Type II pneumocytes, and dust cells.

What is the function of Type I pneumocytes?

Thin cells that allow gas exchange.

What is the function of Type II pneumocytes?

Produce surfactant.

What is the function of dust cells?

Engulf dust, debris, and microorganisms.

What is surfactant?

Substance produced by Type II cells that reduces surface tension in alveoli.

Why is surfactant important?

Prevents alveoli from collapsing.

What can happen when premature babies lack enough surfactant?

Infant respiratory distress syndrome (IRDS).

What is the respiratory membrane?

Thin barrier between alveolar air and blood in pulmonary capillaries.

What structures form the respiratory membrane?

Alveolar wall and capillary wall.

What is the purpose of the respiratory membrane?

Allows O₂ and CO₂ to diffuse between air and blood.

What is the path of oxygen across the respiratory membrane?

Alveoli → Respiratory membrane → Pulmonary capillary blood.

What is the path of carbon dioxide across the respiratory membrane?

Pulmonary capillary blood → Respiratory membrane → Alveoli.

What is diffusion?

Movement of gases from higher partial pressure to lower partial pressure.

What three factors affect gas diffusion?

Partial pressure gradient, membrane thickness, and membrane surface area.

How does increased membrane thickness affect gas exchange?

Slows diffusion.

How does increased surface area affect gas exchange?

Allows more gas exchange.