Respiratory System Development and Anatomy Vocabulary Flashcards

Comprehensive vocabulary flashcards detailing fetal cardiopulmonary development, APGAR scoring, upper and lower respiratory tract structures, alveolar features, and neural control of the lungs based on lecture notes.

Embryonic Period

Fetal lung development stage occurring around the $26\text{th}$ day after fertilization, during which the lungs first appear as small buds rising from the esophagus.

Pseudoglandular Period

Stage of fetal lung development between the $6\text{th}$ and $16\text{th}$ week of gestation where segmental and subsegmental bronchi, all lung segments, goblet cells, and mucous glands appear.

Canalicular Period

Stage of fetal lung development between the $17\text{th}$ and $26\text{th}$ week of gestation where terminal bronchioles proliferate, primitive respiratory bronchioles appear, and lymphatic vessels develop around week $20$.

Terminal Sac Period

Fetal lung development stage from the $26\text{th}$ week of gestation until term ($40$ weeks) where Type I and Type II alveolar cells appear, the entire acinus develops, and pulmonary surfactant begins to appear.

Alveolar Period

Fetal lung development stage starting at $32$ weeks gestation and continuing through childhood ($8$ to $10$ years), during which the number of alveolar-capillary units increases to about $300$ million.

Respiratory Distress Syndrome (RDS)

A common newborn disorder developed due to an immature alveolar-capillary system and an inadequate ability of Type II cells to produce sufficient pulmonary surfactant.

APGAR Scoring System

An evaluation tool measuring heart rate, respiratory effort, muscle tone, reflex irritability, and color at $1$ and $5$ minutes after delivery to assess a newborn's condition and recovery from birth stress.

Cotyledons

The $15$ to $20$ structural segments of a fully developed placenta, each composed of fetal vessels, chorionic villi, and intervillous spaces.

Umbilical Arteries

Two vessels wrapped around the umbilical vein that carry deoxygenated blood (normal $\text{PO}_2$ around $20\,mm\,Hg$ and $\text{PCO}_2$ around $55\,mm\,Hg$) from the fetus to the placenta.

Abruptio Placenta

The premature partial or total separation of the placenta from the wall of the uterus.

Functional Residual Capacity (FRC)

The volume of air that remains in the lungs after a normal exhalation.

Intrapleural Pressure

The pressure within the chest cavity that must decrease to about $-40\,cm\,H_2O$ (and up to $-100\,cm\,H_2O$) to initiate the newborn's first breath.

Vibrissae

Hair follicles located in the vestibule of the nasal cavity that function as filters and serve as the tracheobronchial tree's first line of defense.

Turbinates

Three bony protrusions (superior, middle, and inferior) on the lateral walls of the nasal cavity that separate inspired gas into multiple airstreams to increase contact area for warming and humidifying air.

Paranasal Sinuses

Air-filled cavities in the bones of the skull (maxillary, frontal, ethmoid, sphenoid) communicating with the nasal cavity that provide mucus and aid in sound production.

Choanae

The two passageways in the nasal cavity located between the nares and the nasopharynx.

Rhinitis

Inflammation of the mucous membranes of the nasal cavity accompanied by swelling, excessive mucus production, nasal congestion, and postnasal drip.

Vallecula Epiglottica

A depression or crevice between the base of the tongue and the epiglottis that serves as an important landmark when inserting an endotracheal tube using a curved laryngoscope blade.

Pharyngeal Reflex

Also known as the gag or swallow reflex; produced when laryngeal nerves and muscles are stimulated to prevent aspiration of foods and liquids and keep the tongue base from obstructing the laryngopharynx.

Larynx

The voice box connecting the pharynx to the trachea, which acts as an air passageway, protects against aspiration, and generates speech sounds.

Thyroid Cartilage

The largest single cartilage of the larynx, commonly referred to as the Adam's Apple, suspended from the hyoid bone.

Cricoid Cartilage

Signet ring-shaped cartilage located below the thyroid cartilage; forms the narrowest part of the airway in infants.

Glottis

The space between the true vocal cords (rima glottidis), representing the narrowest part of the airway in adults.

Croup Syndrome

A clinical condition in young children characterized by glottic or subglottic edema and inspiratory stridor, commonly caused by acute epiglottitis or laryngotracheobronchitis (LTB).

Valsalva's Maneuver

A massive movement of the laryngeal walls to midline that tightly seals the glottis to prevent air from escaping during physical exertion such as lifting or coughing.

Conducting Zone

The branching airways from generations $0$ to $19$ (trachea through terminal bronchioles) that serve exclusively as conductors of air.

Respiratory Zone

The branching airways from generations $20$ to $28$ (respiratory bronchioles, alveolar ducts, and alveolar sacs) where gas exchange occurs.

Mucociliary Escalator

A cleansing mechanism present in the conducting zone consisting of pseudostratified ciliated columnar epithelium with cilia beating $1500$ times per minute to move the gel and sol mucus layers toward the larynx.

Mast Cells

Immune cells located in the lamina propria that degranulate upon antigen interaction, releasing mediators such as histamine, leukotrienes, heparin, PAF, and ECF-A.

IgE

The specific antibody/immunoglobulin involved in allergic reactions; normal serum level is approximately $200\,ng/ml$.

Carina

The bifurcation point where the trachea divides into the right and left mainstem bronchi at the level of the $5\text{th}$ thoracic vertebra.

Canals of Lambert

Tiny channels between the inner surface of terminal bronchioles and adjacent alveoli that provide collateral ventilation in conditions like COPD.

Clara Cells

Secretory cells in the terminal bronchioles containing enzymes that detoxify inhaled toxic substances.

Venous Admixture

The mixture of unoxygenated bronchial venous blood with oxygenated blood in the pulmonary veins via bronchopulmonary anastomoses.

Type I Alveolar Cells

Squamous pneumocytes that constitute $95\%$ of the total alveolar surface area.

Type II Alveolar Cells

Granular pneumocytes making up $5\%$ of the alveolar surface area that synthesize and secrete pulmonary surfactant.

Pores of Kohn

Small openings in the interalveolar septa that permit gas movement between adjacent alveoli.

Pulmonary Interstitium

A gel-like matrix supported by collagen fibers surrounding the alveolar-capillary clusters, composed of tight and loose spaces, that limits alveolar distensibility.

Sympathetic Nervous System

Division of the autonomic nervous system ('fight or flight') whose neurotransmitters relax bronchial smooth muscle, increase heart rate, and constrict arterioles.

Parasympathetic Nervous System

Division of the autonomic nervous system whose neurotransmitter (acetylcholine) constricts bronchial smooth muscle, slows heart rate, and increases gastrointestinal activity.

Sympathomimetic Drugs

Medications that mimic the actions of the sympathetic nervous system to induce bronchodilation.

Paraspatholytic Agents

Medications that block cholinergic receptors of the parasympathetic nervous system to inhibit bronchial smooth muscle constriction.

Hilum

The central area on the mediastinal border of each lung where mainstem bronchi, blood vessels, lymphatics, and nerves enter and exit.

Mediastinum

The central cavity of the thoracic cage located between the lungs, containing the heart, trachea, great vessels, esophagus, thymus gland, and lymph nodes.

Pleurisy

Inflammation of the pleural membranes resulting in rough, irritated surfaces that produce sharp thoracic pain and an audible friction rub during breathing.

Pneumothorax

The presence of gas in the pleural cavity that separates the visceral and parietal pleurae, resulting in lung collapse (atelectasis).

Tension Pneumothorax

A severe condition occurring when gas pressure inside the intrapleural space exceeds atmospheric pressure.

Angle of Louis

The manubriosternal joint between the manubrium and body of the sternum, serving as a palpable anatomical landmark for the tracheal carina.

Diaphragm

The principal muscle of ventilation, dome-shaped and innervated by the phrenic nerves, which contracts downward to expand the thoracic volume during inhalation.