Trachea and Lungs Anatomy and Function

These flashcards cover the key terms, definitions, and concepts related to the anatomy and function of the trachea, bronchi, and lungs, as well as gas exchange mechanisms.

Trachea

A long cartilaginous tube connecting the larynx to the bronchi of the lungs.

Cricotracheal ligament

Connects the cricoid cartilage to the trachea and provides strength.

Tracheal cartilages

Incomplete C-shaped cartilages that provide structural support to the trachea.

Annular ligaments

Circular fibrous bands that keep tracheal rings together and support the tracheal wall.

Carina

A ridge at the base of the trachea that separates the openings of the right and left main bronchi.

Lobar bronchi

Secondary bronchi that enter the lobes of the lungs.

Segmental bronchi

Tertiary bronchi that supply bronchopulmonary segments of the lungs.

Bronchioles

Small branches of the bronchi that lead to alveoli; do not have cartilage plates.

Alveoli

Terminal air spaces in the lungs where gas exchange occurs.

Type I pneumocytes

Thin squamous cells that line most of the alveolar surface; involved in gas exchange.

Type II pneumocytes

Secretory cells in the alveoli that produce surfactant.

Surfactant

Substance that reduces surface tension in the alveoli, preventing collapse.

Bronchial structure

Bronchi have smooth muscle layers and ciliated epithelium for transport and protection.

Pulmonary artery

Carries deoxygenated blood from the heart to the lungs.

Pulmonary veins

Bring oxygenated blood from the lungs back to the heart.

Visceral pleura

The membrane that covers the surface of the lungs.

Parietal pleura

The membrane that lines the thoracic cavity.

Pleural cavity

Space between the visceral and parietal pleura, normally filled with a thin film of fluid.

Ciliated epithelium

Type of epithelium in the trachea and bronchi that helps move mucus upward.

Mucosa

Inner layer of the trachea composed of respiratory epithelium and lamina propria.

Submucosa

Connective tissue layer in the trachea containing glands.

Trachealis muscle

Muscle located in the posterior wall of the trachea, allowing flexibility.

Gas exchange

The process occurring in alveoli where oxygen and carbon dioxide are exchanged.

Normal ventilation

4 L/min, amount of air that reaches the alveoli.

Normal perfusion

5 L/min, amount of blood flow that reaches the lungs.

Ventilation/Perfusion (V/Q) ratio

Measurement indicating the efficiency of gas exchange in the lungs.

Hypoxic vasoconstriction

Constriction of pulmonary arterioles in response to low oxygen levels in the alveoli.

Alveolar macrophages

Immune cells in the alveoli that help remove inhaled particles and pathogens.

Interstitial fluid

Fluid that surrounds the alveoli and vessels, playing a role in gas exchange.

Carbonic anhydrase

Enzyme in red blood cells that catalyzes the conversion of CO2 into bicarbonate.

Bicarbonate ion (HCO3-)

Form in which most carbon dioxide is transported in the blood.

Chloride shift

Movement of chloride ions into red blood cells in exchange for bicarbonate.

Oxyhemoglobin

Hemoglobin that is bound to oxygen.

Deoxyhemoglobin

Hemoglobin that is not bound to oxygen.

2,3-diphosphoglyceric acid (2,3-DPG)

A molecule produced by red blood cells that decreases hemoglobin's affinity for oxygen.

Partial pressure of oxygen (PO2)

The pressure exerted by oxygen in the blood, affecting hemoglobin saturation.

Pulmonary embolism

Blood clot that blocks blood flow in the lungs, affecting ventilation/perfusion.

Alveolar ventilation

The amount of air that reaches the alveoli where gas exchange takes place.

Dead space

Alveoli that are ventilated but not perfused with blood.

V/Q mismatch

A condition where ventilation and perfusion are not matched, affecting gas exchange efficiency.

Pulmonary resistance

Opposition to blood flow in pulmonary vessels, influenced by vessel diameter.

Total resistance of pulmonary vasculature

Sum of resistance from alveolar and extra-alveolar blood vessels.

Vasodilation

Widening of blood vessels, decreasing resistance and increasing blood flow.

Vasoconstriction

Narrowing of blood vessels, increasing resistance and decreasing blood flow.

Bronchial circulation

Supply of oxygen-rich blood to the bronchi and lung connective tissues.

Gas diffusion

Process by which gases exchange through the alveolar and capillary walls.

Interalveolar septum

Thin wall separating adjacent alveoli, supporting gas exchange.

Respiratory bronchioles

Bronchioles that participate in gas exchange, leading to alveoli.

Conducting bronchioles

Bronchioles that transport air but do not participate in gas exchange.

Terminal bronchioles

Smallest conducting bronchioles leading to respiratory bronchioles.

Bronchial blood supply

Oxygenated blood from bronchial arteries that nourishes the bronchi.

Diaphragm

Muscle that separates the thoracic and abdominal cavities and aids in respiration.

Pulmonary capillaries

Smallest blood vessels in the lungs where gas exchange occurs.

Pores of Kohn

Small openings between alveoli allowing for communication.

Vascular resistance

Resistance within the pulmonary vasculature affected by vessel diameter.

Type I and Type II cells

Cells in the alveoli involved in gas exchange and surfactant production.

Alveolar sac

Structure comprised of alveoli that facilitates gas exchange.

Histology of the trachea

Study of the microscopic structure of the trachea's tissues.

Histology of the bronchi

Study of the microscopic structure of the bronchi's tissues.

2,3-DPG effect on hemoglobin

Decreases hemoglobin's affinity for oxygen under hypoxic conditions.

Sharp decrease in PO2

Triggers the release of oxygen from hemoglobin to the tissues.

Chemoreceptors

Sensors that detect changes in blood gas levels and regulate respiration.

Autonomic nervous system

Part of the nervous system that controls involuntary actions including lung function.

Gas pressure gradients

Difference in partial pressures driving gas exchange in the lungs.

Surfactant function

Reduces surface tension in alveoli, preventing collapses during expiration.

Immunological role of alveolar macrophages

Remove pathogens and particulates from the lung airspaces.