Thorax, Body Cavities & Cardiovascular Basics – Vocabulary Flashcards

Vocabulary flashcards covering key anatomical terms from the lecture on body cavities, thoracic wall, lymphatics, and introductory cardiovascular concepts.

Thoracic Cavity

Body cavity located above the diaphragm that houses the lungs, heart, and mediastinum.

Diaphragm

Dome-shaped skeletal muscle separating thoracic and abdominal cavities; primary muscle of respiration.

Pleural Cavity

Serous cavity surrounding each lung within the thoracic cavity.

Pericardial Cavity

Serous cavity surrounding the heart within the mediastinum.

Mediastinum

Central compartment of the thorax containing the heart, great vessels, trachea, esophagus, and more (but not the lungs).

Parietal Serous Membrane

Outer layer lining the wall of a body cavity.

Visceral Serous Membrane

Inner layer covering the external surface of an organ.

Serous Fluid

Lubricating fluid between parietal and visceral layers that reduces friction.

Pleura

Collective term for serous membranes of the lungs (parietal pleura + visceral pleura).

Pericardium

Serous membranes of the heart (parietal pericardium + visceral pericardium).

Peritoneum

Serous membranes of the abdominal cavity and its organs.

Thorax

Body region above the diaphragm bounded by the sternum, ribs, and thoracic vertebrae.

Intercostal Space

Space between adjacent ribs containing muscles, vessels, and nerves.

External Intercostal Muscles

Outermost intercostal layer; fibers run "hands-in-pockets" (downward & inward); assist inhalation.

Internal Intercostal Muscles

Middle intercostal layer; fibers run perpendicular to externals; assist forced exhalation.

Innermost Intercostal Muscles

Deepest intercostal layer; fiber direction matches internal layer; protect neurovasculature.

Intercostal Neurovascular Bundle

Vein-Artery-Nerve (VAN) set running along the inferior margin of each rib between internal and innermost muscles.

Phrenic Nerve

Motor nerve to the diaphragm; arises from spinal levels C3-C5 ("C3-4-5 keeps the diaphragm alive").

Inferior Vena Cava (IVC) Hiatus

Opening in the diaphragm at vertebral level T8 for passage of the IVC.

Esophageal Hiatus

Opening in the diaphragm at T10 for the esophagus and vagal trunks.

Aortic Hiatus

Opening in the diaphragm at T12 for the aorta, thoracic duct, and azygos vein; mnemonic: "I 8 10 Eggs A-t 12."

Internal Thoracic Artery

Vertical artery on each side of sternum; gives off anterior intercostal arteries.

Anterior Intercostal Arteries

Small branches off the internal thoracic artery supplying anterior intercostal spaces.

Posterior Intercostal Arteries

Branches of the thoracic aorta supplying posterior intercostal spaces; anastomose with anterior branches.

Azygos Vein

Unpaired vein on right posterior thoracic wall draining posterior intercostal veins into the superior vena cava.

Hemiazygos & Accessory Hemiazygos Veins

Left-sided veins that drain into the azygos system from lower and upper thoracic posterior walls.

Right Lymphatic Duct

Small duct draining lymph from right head & neck, right upper limb, and right thorax (≈25% of body).

Thoracic Duct

Largest lymphatic vessel; drains lymph from rest of body (≈75%) into left subclavian vein.

Lymph Node

Small, bean-shaped lymphoid organ that filters lymph and houses immune cells.

Thymus

Lymphoid organ anterior to the heart active in T-cell maturation; involutes after puberty.

Spleen

Largest lymphoid organ (left upper abdomen) that filters blood, recycles RBCs, and produces lymphocytes.

Tonsils

Aggregations of lymphoid tissue (palatine, lingual, pharyngeal) guarding entryways of respiratory & digestive tracts.

Palatine Tonsils

Paired tonsils visible on either side of the oropharynx; commonly removed in tonsillectomy.

Pharyngeal Tonsil (Adenoid)

Single tonsil in roof of nasopharynx; may enlarge and obstruct airflow.

Lingual Tonsil

Lymphoid tissue on posterior aspect of tongue.

Pulmonary Circuit

Right-sided heart circulation sending deoxygenated blood to lungs and returning oxygenated blood to left heart.

Systemic Circuit

Left-sided heart circulation sending oxygenated blood to body tissues and returning deoxygenated blood to right heart.

Pulmonary Arteries

Arteries carrying deoxygenated blood from right ventricle to lungs (exception to usual oxygen rule).

Pulmonary Veins

Veins carrying oxygenated blood from lungs to left atrium (exception to usual oxygen rule).

Apex of the Heart

Inferior pointed tip of the left ventricle that points down and to the left.

Base of the Heart

Posterior-superior portion where great vessels attach.

Right Atrium

Heart chamber receiving deoxygenated systemic blood via SVC, IVC, and coronary sinus.

Left Atrium

Heart chamber receiving oxygenated blood from four pulmonary veins.

Right Ventricle

Heart chamber pumping deoxygenated blood into the pulmonary trunk.

Left Ventricle

Heart chamber pumping oxygenated blood into the aorta.

Pectinate Muscles

Ridge-like muscular folds lining atrial walls, especially prominent in right atrium.

Fossa Ovalis

Oval depression in interatrial septum; remnant of fetal foramen ovale.