Chapter 23 – The Respiratory System (Tortora & Derrickson, 15e)

Flashcards cover structure, function, mechanics, gas exchange, transport, regulation, and clinical aspects of the respiratory system as presented in Chapter 23 lecture notes.

What are the four main functions of the respiratory system?

1) Provide O2 and remove CO2, 2) Enable speech, 3) House olfactory receptors for smell, 4) Help regulate blood pH via CO2 removal

Why is CO2 considered physiologically important?

It influences blood pH and drives ventilation-perfusion matching; abnormal CO2 can rapidly disturb acid–base balance.

Name the three integrated processes collectively called respiration.

1) Pulmonary ventilation, 2) External (pulmonary) respiration, 3) Internal (tissue) respiration

Which body system transports respiratory gases between lungs and tissues?

The cardiovascular system

Pulmonary ventilation is the ___ of air into and out of the lungs.

movement

In external respiration, gas exchange occurs between __ and __.

alveoli and pulmonary capillary blood

Internal respiration refers to gas exchange between __ and __.

systemic capillary blood and tissue cells

Structurally, the respiratory system is divided into which two parts?

Upper respiratory system and lower respiratory system

Functionally, the respiratory system is divided into which two zones?

Conducting zone (air passageways) and respiratory zone (sites of gas exchange)

List the organs that belong to the upper respiratory system.

Nose, nasal cavity, paranasal sinuses, and pharynx

List the organs that belong to the lower respiratory system.

Larynx, trachea, bronchi and branches, lungs, and alveoli

What are the three functions of the nasal conchae and meatuses?

Increase surface area, enhance air turbulence, and warm/moisten/filter incoming air

State three functions of the paranasal sinuses.

Lighten the skull, secrete mucus, and help warm & moisten air

Which epithelium lines the nasopharynx?

Pseudostratified ciliated columnar epithelium

Which epithelium lines the oro- and laryngopharynx?

Non-keratinized stratified squamous epithelium

The larynx is composed of how many cartilages?

Nine (thyroid, cricoid, epiglottis, paired arytenoid, paired cuneiform, paired corniculate)

What structure of the larynx acts as a lid to prevent food from entering the airway?

Epiglottis

Vocal folds produce sound when they ___.

vibrate as air passes through

During Valsalva’s maneuver the glottis __ to increase intra-abdominal pressure.

closes

Name the three histologic layers of the tracheal wall.

Mucosa, submucosa, and adventitia

What prevents the trachea from collapsing?

16–20 C-shaped rings of hyaline cartilage

Which first-aid procedure forces air from a victim’s lungs to expel an obstructing object?

Heimlich maneuver

At which vertebral level does the trachea bifurcate into primary bronchi?

Superior border of T5

The end of the conducting zone is the ____.

terminal bronchiole

Gas exchange begins in which airway?

Respiratory bronchioles (start of respiratory zone)

How many lobes does the right lung have?

Three (superior, middle, inferior)

Name the membrane that directly covers the lung surface.

Visceral pleura

Type I alveolar cells form the ___.

major part of the alveolar wall and gas diffusion surface

Which alveolar cell secretes surfactant?

Type II (septal) alveolar cell

List the four layers of the respiratory membrane in order.

1) Alveolar epithelium, 2) Epithelial basement membrane, 3) Capillary basement membrane, 4) Capillary endothelium

What is ventilation-perfusion coupling?

Pulmonary vasoconstriction diverts blood from poorly ventilated alveoli to well-ventilated regions.

Boyle’s law states that pressure of a gas varies ___ with volume.

inversely

Which muscle is the primary driver of quiet inhalation?

Diaphragm

During forced exhalation, name two muscle groups that contract.

Internal intercostals and abdominal muscles (e.g., rectus abdominis)

Define lung compliance.

The ease with which lungs and thoracic wall expand (∆V / ∆P).

Surface tension inside alveoli is reduced by ___.

pulmonary surfactant

Give the medical term for normal quiet breathing.

Eupnea

Rapid breathing rate is called ____.

Tachypnea

Provide one example of a modified respiratory movement and its stimulus.

Coughing – initiated by irritants or foreign bodies in larynx/trachea

Define tidal volume (TV).

Amount of air inhaled or exhaled during normal quiet breathing (~500 mL).

Which law explains that each gas in a mixture exerts its own partial pressure?

Dalton’s law

According to Henry’s law, gas solubility in a liquid depends on __ and __.

its partial pressure and solubility coefficient

State the normal PO2 of alveolar air.

≈105 mmHg

What percentage of O2 is transported dissolved in plasma?

~1.5 %

Carbaminohemoglobin represents what percent of CO2 transport?

Approximately 23 %

What enzyme catalyzes CO2 hydration to form carbonic acid in RBCs?

Carbonic anhydrase

How many O2 molecules can one hemoglobin (Hb) carry?

Four

List five factors that decrease Hb affinity for O2 (promote unloading).

Low PO2, low pH (high CO2), high temperature, high BPG, fetal vs adult Hb (fetal has higher affinity)

Which part of the medulla sets the basic rhythm of breathing?

Ventral respiratory group (VRG)

The dorsal respiratory group (DRG) integrates signals from ___.

peripheral chemoreceptors and stretch receptors, then relays to VRG

Pontine respiratory centers mainly ____.

smooth transitions between inspiration and expiration and fine-tune breathing during activities like speech

Hypercapnia is defined as a slight rise in arterial ___.

PCO2 (and H+)

Name two peripheral chemoreceptor locations.

Carotid bodies and aortic bodies

During acidosis, ventilation rate will ___.

increase (hyperventilation) to blow off CO2

List three stimuli that increase breathing rate and depth.

↑PCO2, ↓PO2 (to ~50 mmHg), increased body temperature, voluntary hyperventilation, limbic anticipation, etc.

How does exercise affect pulmonary perfusion?

Cardiac output increases, raising blood flow to lungs and tripling O2 diffusing capacity.

Mention two age-related changes that lower respiratory efficiency.

Decreased vital capacity and reduced ciliary activity (also lower alveolar macrophage function, lower blood O2)

What common congenital defect involves an abnormal connection between trachea and esophagus?

Tracheoesophageal fistula (patent)

Define chronic obstructive pulmonary disease (COPD) in simple terms.

Progressive, irreversible airflow obstruction (e.g., emphysema, chronic bronchitis).

What is infant respiratory distress syndrome primarily due to?

Insufficient surfactant production leading to high alveolar surface tension

State the role of the respiratory pump in venous return.

Pressure changes during breathing help draw venous blood back to the heart.

Which hormone activation occurs in lung endothelium and affects BP?

Angiotensin-converting enzyme (ACE) converts angiotensin I to angiotensin II

Costal breathing primarily uses which muscles?

External intercostal muscles (with minimal diaphragm movement)

Diaphragmatic breathing involves visible movement of the ___.

abdomen due to diaphragm contraction

Define lung vital capacity (VC).

Maximum amount of air expired after maximal inspiration (≈4.8 L males).

What triggers the Hering–Breuer inflation reflex?

Stretch receptors in bronchi/bronchioles inhibit inspiration to prevent over-inflation

Which gas law underlies hyperbaric oxygen therapy?

Henry’s law (greater pressure dissolves more O2 in blood)