Chapter 22 The Respiratory System

Ventilation

Ventilation

the process of moving gases into and out of the lungs

conducting zone

nose, pharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles

respiratory zone

respiratory bronchioles, alveolar ducts, alveoli

upper respiratory system

nose, nasal cavity, paranasal sinuses, pharynx

lower respiratory system

larynx, trachea, bronchi, bronchioles, alveoli

respiratory mucosa

mucus-covered membrane that lines the tubes of the respiratory tree

external nares

two openings of the nose; i.e. nostrils

nasal vestibule

nasal cavity superior to nostrils

nasal cavity

located within the nose and divided into right and left portions by a nasal septum

nasal conchae (turbinates)

superior, middle, and inferior; form narrow passages so that air contacts mucous membranes (cleanses and warms air); scroll-shaped bones that project into cavity; increase surface area inside nose

nasopharynx

region of the pharynx at the back of the nose and above the soft palate

hard palate

roof of the mouth

soft palate

muscular posterior (back) portion of the palate

oropharynx

central portion of the pharynx between the roof of the mouth and the upper edge of the epiglottis

laryngopharynx

lower part of the pharynx, just below the oropharyngeal opening into the larynx and esophagus

larynx

voice box; passageway for air moving from pharynx to trachea; contains vocal folds

vocal folds

Mucosal folds that function in voice production (speech); also called the true vocal cords.

vestibular folds

ligament tissue; prevents entry of foreign objects into the larynx; protect vocal cords

thyroid cartilage

The wing-shaped plate of hyaline cartilage that sits anterior to the larynx and forms the Adam's apple.

thyroid prominence

A protrusion in the thyroid cartilage referred to as the "Adam's apple," which is located just below the thyroid notch.

cricoid cartilage

the ring-shaped structure that forms the lower portion of the larynx; hyaline cartilage

epiglottis

a flap of elastic cartilage at the root of the tongue, which is depressed during swallowing to cover the opening of the windpipe.

glottis

space between the vocal folds

hyoid bone

U-shaped bone at the base of the tongue that supports the tongue and its muscles.

choking

Food or foreign object blocks the airway or throat.

cricothyrotomy

a surgical incision into the membrane between the cricoid bone and the thyroid cartilage; done for the purpose of providing an airway when breathing through the mouth and nose is not an option

tracheotomy/tracheostomy

temporary or permanent opening made below cricoid cartilage

trachea

a large membranous tube reinforced by rings of cartilage, extending from the larynx to the bronchi; conveying air to and from the lungs; the windpipe.

voice box

another name for the larynx

sneezing reflex

stimulated by irritants in the nasal cavity; a sudden forceful expulsion of air through the nose and mouth orchestrated by the medulla oblongata

coughing reflex

stimulus: irritation of respiratory tract, specifically triggered when food or liquids touch the vestibular or vocal folds or trachea;
response: sudden explosive ejection of air
comments: coordinated by medullary coughing center

phonation

sound production at the larynx

articulation

the physical production of particular speech sounds with use of the tongue and teeth

carina

a ridge of cartilage in the trachea that occurs between the division of the two main bronchi

extrapulmonary

outside the lungs

intrapulmonary

within the lungs

bronchitis

inflammation of the bronchi

bronchiolitis

inflammation of the bronchioles

pneumonia

inflammation of the lungs

allergy

a specific reaction of the immune system to a foreign and frequently harmless substance

asthma

episodes of breathing difficulty due to narrowed or obstructed airways

bronchodilation

Dilation of bronchial airways
Caused by sympathetic ANS activation
Reduces resistance

bronchoconstriction

the contraction of smooth muscle that lines the bronchial passages that results in a decreased internal diameter of the airway and increased resistance to airflow; caused by parasympathetic activity; caused by histamine

alveolar marcrophages

macrophages in the alveoli

alveolus

tiny air sac at the end of a bronchiole in the lungs that provides surface area for gas exchange to occur; singular

alveoli

tiny sacs of lung tissue specialized for the movement of gases between air and blood; plural

pneumocytes type I

simple squamous epithelial cells making up most of the alveolar surface

pneumocytes type II

scattered among squamous cells; produce surfactant

surfactant

A liquid lipid and protein substance that coats the alveoli in the lungs, decreases alveolar surface tension, and keeps the alveoli expanded

cardiac notch

a concave space on the left lung in which the heart lies

hilum of the lung

midline region where the bronchi, blood vessels, and nerves enter and exit the lungs

root of the lung

Complex of connective tissues, nerves, and vessels in hilum
Anchored to the mediastinum

parietal pleural membrane

the outer layer of pleura that lines the inner wall of the thoracic cavity

visceral pleural membrane

The layer of serous membrane that is firmly attached to the surface of a lung

pleural fluid

serous fluid necessary to prevent friction between the pleural membranes

pleural cavity

*The space between the two pleural membranes that surround each lung. Filled with lubricating fluid.
*Airtight space between fold of the pleural membranes; contains watery lubricating serous fluid that prevents friction between the membranes when they rub together during respiration

alveolar ventilation

movement of air into and out of the alveoli

pulmonary ventilation

movement of air into and out of the lungs

respiratory minute volume

The amount of air moved into and out of the respiratory system each minute

alveolar minute volume

The amount of air that actually reaches the alveoli per minute.

atmospheric pressure

the pressure exerted by atoms and molecules in the atmosphere surrounding Earth, resulting from collisions of these particles with objects

hypoxia

deficiency in the amount of oxygen reaching the tissues

eupnea

normal breathing at rest

hyperpnea

increase in depth and rate of breathing

intrapulmonary pressure

pressure within the lungs

intrapleural pressure

pressure within the pleural cavity

compliance

ability to stretch; elasticity

respiratory rate

number of breaths per minute

tidal volume

Amount of air that moves in and out of the lungs during a normal breath

Expiratory Reserve Volume (ERV)

Amount of air that can be forcefully exhaled after a normal tidal volume exhalation

Inspiratory Reserve Volume (IRV)

Amount of air that can be forcefully inhaled after a normal tidal volume inhalation

Vital Capacity (VC)

TV + IRV + ERV

Residual Volume (RV)

Amount of air remaining in the lungs after a forced exhalation

Minimal Volume (MV)

volume of air remaining in the lungs even after RV has been eliminated.

Total Lung Capacity (TLC)

maximum amount of air contained in lungs after a maximum inspiratory effort

Functional Residual Capacity (FRC)

volume of air remaining in the lungs after a normal tidal volume expiration

Boyle's Law

inverse relationship between pressure and volume

Dalton's Law

The total pressure of a mixture of gases is the sum of the individual pressures (Ptotal=P1+P2+P3...)

Henry's Law

the solubility of a gas in a liquid is directly proportional to the partial pressure of that gas on the surface of the liquid

hemoglobin

A four-subunit protein found in red blood cells that binds oxygen. Each subunit contains a heme group, a large multi-ring molecule with an iron atom at its center. One hemoglobin molecule can bind four oxygen molecules in a cooperative manner.

hemoglobin saturation

The percentage of heme units in a hemoglobin molecule that contain bound oxygen

Hemoglobin Saturation Curve

fraction of oxygen-saturated hemoglobin relative to total hemoglobin in the blood

Bohr effect

The tendency of certain factors to stabilize the hemoglobin in the tense conformation, thus reducing its affinity for oxygen and enhancing the release of oxygen to the tissues. The factors include increased pCO2, increased temperature, increased bisphosphoglycerate (BPG), and decreased pH. Note that the Bohr effect shifts the oxy-hemolobin saturation curve to the right.

carbonic anhydrase

An enzyme present in erythrocytes (as well as in other places) that catalyzes the conversion of CO2 and H2O into carbonic acid (H2CO3).

dorsal respiratory group (DRG)

A portion of the medulla oblongata where the primary respiratory pacemaker is found.

ventral respiratory group (VRG)

Inspiratory and expiratory center
Functions only in forced breathing

pneumotaxic center

area of the upper pons in the brain that modulates activity of the apneustic center

apneustic center

area of the pons; adjust pace of respiration causes strong, sustained inspiratory movements.

hypercapnia

excessive carbon dioxide in the blood