Respiratory and Cardiovascular System

Vocabulary practice flashcards covering anatomical terminology, structural boundaries, vascular pathways, respiratory mechanics, mediastinal divisions, and the cardiac conduction system from Anatomy Lecture 2.

Conducting Portion

The functional division of the respiratory system that transports air and conditions it by warming, moistening, and filtering.

Respiratory Portion

The functional division of the respiratory system consisting of a thin, moist, delicate membrane that acts as the site of gas exchange ($O_2$ passes from air to blood; $CO_2$ passes from blood to air).

Nasal Cavity Boundaries

The structural borders enclosing the nasal cavity: the nasal cartilage anteriorly, the ethmoid bone superiorly, the hard and soft palate inferiorly, and the nasopharynx posteriorly.

Inferior Nasal Meatus

The nasal passage located inferior to the inferior nasal concha that receives drainage from the nasolacrimal duct.

Middle Nasal Meatus

The nasal passage located inferior to the middle nasal concha that receives drainage from the frontal sinus, anterior ethmoid sinus, and maxillary sinus.

Superior Nasal Meatus

The nasal passage located inferior to the superior nasal concha that receives drainage from the sphenoid sinus and posterior ethmoid sinus.

Nasopharynx

The uppermost region of the pharynx extending from the nasal cavity to the soft palate.

Oropharynx

The middle region of the pharynx extending from the soft palate to the epiglottis.

Laryngopharynx

The lower region of the pharynx extending from the epiglottis to the oesophagus.

Pump-Handle Movement

The movement of the upper ribs during ventilation that increases the antero-posterior diameter of the thoracic cavity.

Bucket-Handle Movement

The movement of the lower ribs during ventilation that increases the transverse diameter of the thoracic cavity.

Diaphragm

The primary muscle of respiration that separates the thorax from the abdomen, doming superiorly (higher on the right side); it contracts and flattens during inspiration, relaxes and domes during expiration, and is innervated by the phrenic nerve ($C3, C4, C5$).

Central Tendon

The central aponeurotic sheet of the diaphragm towards which all of its peripheral muscle fibres converge.

Phrenic Nerve

The motor nerve arising from cervical spinal cord segments $C3, C4, \text{and } C5$ ('keeps the diaphragm alive') that innervates the diaphragm.

Accessory Muscles of Respiration

Muscles recruited during vigorous and forced ventilation to alter thoracic dimensions, specifically including the pectoralis major, pectoralis minor, and serratus anterior.

Intercostal Muscles

The three muscular layers occupying the intercostal spaces between ribs: the external intercostal, internal intercostal, and innermost intercostal muscles.

Intercostal Neurovascular Bundle

The grouping of vessels and nerves located between the internal and innermost intercostal muscles, ordered from superior to inferior as intercostal vein, intercostal artery, and intercostal nerve.

Visceral Pleura

The delicate serous membrane layer that closely covers and adheres directly to the external surface of the lungs.

Parietal Pleura

The outer serous membrane layer that lines the inner surface of the thoracic chest wall, mediastinum, and diaphragm.

Pleural Cavity

The potential space between the parietal and visceral pleura containing a thin film of serous fluid that enables frictionless lung movement and creates surface tension aiding inspiration.

Bronchial Tree

The branching network of airways through which air passes: Trachea $\rightarrow$ Primary bronchi $\rightarrow$ Lobar (secondary) bronchi $\rightarrow$ Segmental (tertiary) bronchi $\rightarrow$ Terminal bronchiole.

Alveolar Sac Capillary Bed

The network of microscopic vessels surrounding the alveolar sacs that receives deoxygenated blood from the heart via pulmonary arteries and returns oxygenated blood to the heart via pulmonary veins.

Right Lung

The lung divided into three lobes (superior, middle, and inferior) by two fissures (horizontal fissure and oblique fissure).

Left Lung

The lung divided into two lobes (superior and inferior) by a single oblique fissure.

Hilum of the Lung

The medial depression through which structures forming the root of the lung (bronchi, pulmonary vessels, lymphatics, and nerves) enter and exit the lung parenchyma.

Superior Mediastinum

The compartment of the thoracic cavity situated above the plane passing through the sternal angle and the $T4/T5$ intervertebral disc, containing the trachea, oesophagus, and great vessels.

Arch of the Aorta

The central curved portion of the aorta in the superior mediastinum that gives off three major arterial branches: the brachiocephalic trunk, left common carotid artery, and left subclavian artery.

Middle Mediastinum

The central division of the inferior mediastinum that contains the heart and the pericardium.

Posterior Mediastinum

The posterior division of the inferior mediastinum located behind the pericardium, containing the oesophagus, descending aorta, thoracic duct, azygous vein, and hemiazygous vein.

Atrioventricular (AV) Valves

The heart valves located between the atria and the ventricles that ensure unidirectional blood flow, comprising the tricuspid valve on the right side and the mitral valve on the left side.

Semilunar Valves

The pocket-like valves situated at the outflow tracts of the heart ventricles that prevent reflux of blood into the ventricles, comprising the aortic valve and pulmonary valve.

Chordae Tendineae

Fibrous tendinous cords that tether the cusps of the atrioventricular valves to the papillary muscles, preventing valve inversion during ventricular systole.

Papillary Muscles

Muscular projections from the ventricular myocardium that contract during systole to pull on the chordae tendineae and keep the atrioventricular valve cusps closed against high pressure.

Coronary Arteries

The right and left arterial branches that arise directly from the aortic sinuses of the ascending aorta to supply oxygenated blood to the heart muscle (myocardium).

Crista Terminalis

A smooth, internal vertical muscular ridge in the right atrium that demarcates the pectinate muscle from the smooth posterior sinus venarum.

Fossa Ovalis

An oval-shaped depression situated on the interatrial septum of the right atrium, representing the closed embryonic foramen ovale.

Moderator Band

A muscular band traversing the right ventricular chamber from the interventricular septum to the base of the anterior papillary muscle.

Sinoatrial (SA) Node

The specialized cardiac tissue situated in the right atrium that acts as the internal pacemaker of the heart by generating action potentials to initiate atrial contraction.

Atrioventricular (AV) Node

The node of specialized cardiac tissue that receives action potentials from the SA node via internodal pathways, delaying impulse propagation across the atria before transmitting it to the ventricles.

Bundle of His (A-V Bundle)

The electrical conduction tract carrying action potentials from the AV node through the fibrous skeleton of the heart before branching into the left and right bundle branches.

Purkinje Fibres

Specialized subendocardial conducting fibres continuous with the bundle branches that rapidly spread depolarizing excitation through the ventricular walls, inducing ventricular contraction from the apex upward.

Autonomic Regulation of the SA Node

The dual extrinsic control of heart rate wherein sympathetic stimulation increases firing rate, while parasympathetic stimulation via the vagus nerve (CN X) slows firing rate to maintain homeostasis.