Lecture Monday 12.1-12.3

Flashcards covering the anatomy, cell types, and mechanical laws (Boyle's Law) of the human respiratory system based on the lecture transcript.

Conduction Zone

The classification of organs whose job is to move air in and out of the respiratory zone, ending where respiratory bronchioles begin.

Respiratory Zone

The area where gases are exchanged between the blood and the air inside the lungs, occurring in the respiratory bronchioles and alveolar sacs.

Respiration

The primary function of the respiratory system focused on oxygenating blood and managing the levels of $CO_2$ within the blood.

Pulmonary Ventilation

The movement of air in and out of the lungs, broken down into two phases: inhalation (inspiration) and exhalation (expiration).

Phonation

A non-respiratory process involving the production of speech and vocalization by pushing air through the vocal folds.

Valsalva Maneuver

The action of bearing down to increase abdominal pressure to help expel contents of the abdominal pelvic cavity, such as during childbirth or defecation.

Angiotensin II

A hormone activated in the respiratory system that has a powerful effect on raising blood pressure and maintaining homeostasis during extreme dehydration.

Nasal Concha

Also known as turbinates, these ethmoid bone protrusions spin air to clean and warm it, preventing cold air from causing vasoconstriction in lung blood vessels.

Pharynx

A vertical tube known as the throat that is divided into three regions: nasopharynx, oropharynx, and laryngeal pharynx.

Larynx

Known as the voice box, this organ serves as the opening to the trachea and acting as the cutoff between the upper and lower respiratory tracts.

Epiglottis

A flap of elastic cartilage in the larynx that pops down during swallowing to prevent food from entering the airway.

Glottis

The opening within the larynx where folds of mucous membrane (vocal cords) open and close to create sound.

Trachea

The airway tube that remains patent (open) due to stacked C-shaped incomplete rings of hyaline cartilage.

Carina

The specialized cartilage ring at the base of the trachea where it splits into bronchi; it contains sensory receptors that trigger deep, forceful coughs.

Secondary Bronchi

Also called lobar bronchi, there are three in the right lung and two in the left lung, each serving a specific lobe.

Tertiary Bronchi

Also known as segmental bronchi, these serve individual segments of the lung which have their own independent circulation.

Bronchioles

Small branches of the bronchial tree that lack cartilage and use smooth muscle to control diameter and airflow via constriction and dilation.

Terminal Bronchioles

The smallest true bronchioles that mark the end of the conducting zone.

Alveolar Type I Cells

Simple squamous epithelial cells that are extremely flat, creating a thin membrane optimized for rapid gas diffusion.

Alveolar Type II Cells

Cells that secrete surfactant, a lipid-based molecule that breaks water surface tension to prevent the air sacs from collapsing.

Alveolar Macrophages

Immune cells derived from monocytes that live in lung tissue to consume inhaled debris, bacteria, and viruses.

Respiratory Membrane

A thin barrier composed of the alveolar type I cell, a thin basal lamina, and the capillary epithelial cell through which gas exchange occurs.

Pleura

The serous membrane of the lungs consisting of a visceral layer attached to the organ and a parietal layer attached to the thoracic wall.

Boyle's Law

A gas law stating that at a constant temperature, the pressure and volume of a gas are inversely related: $P \times V = \text{constant}$.

Atmospheric Pressure

The pressure of environmental gases, which is approximately $760,mmHg$ at sea level.

Intrapulmonary Pressure

The air pressure within the lungs that fluctuates during breathing to create the gradients needed for ventilation.

Intrapleural Pressure

The pressure within the pleural cavity, which must remain approximately $4,mmHg$ lower than intrapulmonary pressure to prevent lung collapse.

Pneumothorax

A condition characterized by a collapsed lung, often caused by air entering the pleural cavity and equilibrating the intrapleural pressure.

Diaphragm

The primary muscle of inspiration that flattens and moves inferiorly upon contraction to increase thoracic volume.

External Intercostals

Muscles located between the ribs that contract to elevate the rib cage during inspiration.

Internal Intercostals

Accessory muscles of expiration that pull the ribs inward to help push air out of the lungs during forced exhalation.

Tidal Breathing

The regular, shallow breathing performed while at rest using only primary muscles like the diaphragm.