Thoracic Cavity Anatomy and Physiology

These vocabulary flashcards cover the anatomical features, clinical correlates, and physiological processes related to the thoracic cavity, lungs, heart, and mediastinum as described in the lecture notes.

Right lung

An organ consisting of $3$ lobes (superior, middle, and inferior) and two fissures (horizontal and oblique).

Left lung

An organ consisting of $2$ lobes (superior and inferior) separated by an oblique fissure and featuring a cardiac notch.

Visceral pleura

The serous membrane layer that closely covers the lungs and adheres to all their surfaces.

Parietal pleura

The outer serous membrane layer that lines the pulmonary cavities and adheres to the thoracic wall, mediastinum, and diaphragm.

Pleural cavity

The potential space between the visceral and parietal layers of pleura containing a capillary layer of serous pleural fluid.

Pulmonary collapse

A condition caused by the admission of air into the pleural cavity, which causes the lung to lose its negative pressure.

Hemothorax

The accumulation of blood in the pleural cavity, which can affect breathing and pressure gradients.

Right main bronchus

A passage that is more vertical, shorter, and wider than its left counterpart, making it more susceptible to aspiration.

Hilum of the lung

A wedge-shaped area on the mediastinal surface of each lung through which the structures forming the root of the lung pass.

Bronchial arteries

Vessels that supply oxygenated blood to the supporting tissues of the lungs and the visceral pleura.

Azygos vein

A vessel that drains the posterior intercostal veins and forms a direct connection between the $IVC$ and $SVC$.

Pulmonary plexuses

Nerve networks containing sympathetic fibers from the sympathetic trunks and parasympathetic fibers from the vagus nerves ($CN X$).

Superior mediastinum

The division of the mediastinum extending from the superior thoracic aperture to the transverse thoracic plane at the $T4-T5$ level.

Fibrous pericardium

The tough outer layer of the pericardial sac that stabilizes the heart and prevents overdilation.

Pericardiacophrenic ligament

The structure representing the continuity of the fibrous pericardium with the central tendon of the diaphragm.

Oval fossa

A remnant of the fetal oval foramen, located in the interatrial septum of the right atrium.

Pectinate muscles

Rough, muscular ridges found within the right atrium and the auricles.

Septomarginal trabecula

Also known as the moderator band, it is a curved muscular bundle in the right ventricle that carries part of the AV bundle.

Systole

The period of the cardiac cycle characterized by ventricular contraction and emptying.

Diastole

The period of the cardiac cycle characterized by ventricular relaxation and filling.

Ligamentum arteriosum

The fibrous remnant of the fetal ductus arteriosus that connected the pulmonary trunk to the arch of the aorta.

Left recurrent laryngeal nerve

A branch of the vagus nerve that loops under the arch of the aorta and ascends to the larynx.

Thoracic duct

The largest lymphatic vessel in the body, which traverses the superior thoracic aperture and enters the left venous angle.

Internal thoracic arteries

The primary source of arterial blood supply to the pericardium.

SA node

The pacemaker of the heart that initiates impulses propagated through the atrial musculature to the AV node.

Plexus

A network of nerves, such as the cardiac plexus located on the anterior aspect of the tracheal bifurcation.

Triple coronary artery bypass

A surgical procedure using vein grafts (often from the leg) to bypass obstructions in the coronary arteries.

Aortic area auscultation site

The clinical listening point located at the right $2nd$ intercostal space at the upper sternal border.

Mitral area auscultation site

The clinical listening point located at the left $5th$ intercostal space.

Phrenic nerve

A nerve originating from $C3, C4,$ and $C5$ that provides motor supply to the diaphragm and sensory fibers to the pericardium.