chaoter 1 A&P of the Respiratory system

Nose (nasal cavity)

Main functions are to filter large dust and debris, humidify the air, and heat the air before it reaches the lungs.

Mucus layer

Protective gel lining the airways that traps debris; moved upward by ciliary action to be expelled or swallowed.

Ciliary action

Movement of cilia in the mucus layer that creates the escalator effect, pushing mucus toward the pharynx for removal.

Alveoli

Tiny air sacs in the lungs where gas exchange between air and blood occurs.

Epiglottis

Flap that prevents food and liquid from entering the trachea during swallowing.

Pleural friction rub

A sound produced when pleural surfaces rub together due to inflammation, often described as a wood-dock creak.

Cartilage rings in airways

Rings of cartilage in larger airways that keep them open; smaller airways rely on soft tissue, which can collapse without support.

Right atrium

Right-hearted chamber that receives deoxygenated blood from the body.

Right ventricle

Right-hearted chamber that pumps deoxygenated blood to the lungs via the pulmonary artery.

Pulmonary artery

Blood vessel that carries deoxygenated blood from the right ventricle to the lungs.

Pulmonary veins

Blood vessels that return oxygenated blood from the lungs to the left atrium.

Deoxygenated blood

Blood that has released its oxygen to tissues and is returning to the heart.

Lymphatic system

Network that drains extracellular fluid and returns it to circulation; moves fluid via valves and muscle contractions, and has no heart-like pump.

Hemodynamics

Study of pressures and flows of blood within the circulatory system.

Negative intrathoracic pressure

Inhalation creates negative pressure in the thoracic cavity, drawing air into the lungs.

Diaphragm

Primary muscle of respiration; contraction enlarges the thoracic cavity to create negative pressure for inhalation.

Phrenic nerve (C3–C5)

Nerve roots that innervate the diaphragm; damage can halt spontaneous breathing.

Retractions

Visible use of neck and chest muscles to breathe, indicating respiratory distress.

Nose breathing in children

Children are primarily nose breathers; nasal flaring and visible effort indicate distress or difficulty breathing.

Sympathetic nervous system

Divides autonomic control that increases heart rate and contractility (fight-or-flight responses).

Parasympathetic nervous system

Divides autonomic control that slows heart rate and conserves energy (rest-and-digest).

Adrenaline (epinephrine) effect on the heart

Sympathetic hormone that increases heart rate and the force of contraction.

Pleural lubrication

Fluid between pleural layers that reduces friction during breathing motions.

Mechanical ventilation concepts

Inspiration is driven by negative pressure in natural breathing; exhalation is passive; mechanical ventilation often uses positive pressure to move air in and out.

Upper Airway

Consists of the nose, oral cavity, pharynx, and larynx; functions include conducting air, humidifying and warming/cooling inspired air, preventing foreign materials from entering the tracheobronchial tree, and playing a role in speech and smell.

Nose

Filters, humidifies, and conditions inspired air and houses olfactory structures as part of the upper airway.

Oral Cavity

Part of the upper airway; includes the vestibule, tongue (intrinsic and extrinsic muscles), lingual frenulum, hard palate, soft palate, and palatine arches.

Vestibule (Oral Cavity)

Entrance area of the oral cavity that precedes the main oral cavity proper.

Tongue (Intrinsic/Extrinsic Muscles)

Muscles that control the shape and movement of the tongue; essential for speech, swallowing, and manipulation of food.

Lingual Frenulum

Mucous membrane fold attaching the tongue to the floor of the mouth, limiting tongue movement.

Hard Palate

Bony anterior part of the palate that separates the oral and nasal cavities.

Soft Palate

Flexible posterior part of the palate that closes off the nasopharynx during swallowing.

Palatine Arches

Arches of tissue containing lymphatic tissue that extend from the soft palate to the walls of the pharynx.

Pharynx

Muscular passage divided into nasopharynx, oropharynx, and laryngopharynx; conduit for inspired air and swallowed material.

Nasopharynx

Upper part of the pharynx behind the nasal cavity.

Oropharynx

Middle section of the pharynx behind the oral cavity; passage for air and food.

Laryngopharynx

Lower part of the pharynx leading to the esophagus and larynx.

Larynx

Voice box that routes air between pharynx and trachea, protects against aspiration, and generates sounds for speech.

Tracheobronchial Tree (Cartilaginous Airways)

Trachea and bronchi up to subsegmental levels; cartilage-supports the conducting airways that transport air to sites of gas exchange.

Tracheobronchial Tree (Noncartilaginous Airways)

Bronchioles and terminal bronchioles; conduct air and also serve as sites of gas exchange.

Primary Lobule

Functional unit of the lung; a parcel of alveolar units supplied by a terminal bronchiole, collectively part of the lung parenchyma.

Alveolar Epithelium

The epithelial lining of the alveoli where gas exchange occurs.

Pores of Kohn

Small pores between adjacent alveoli that allow collateral ventilation.

Alveolar Macrophages

Immune cells within alveoli that phagocytose inhaled particles and debris.

Interstitium

Connective tissue space around alveoli that provides support and participates in gas exchange processes.

Pulmonary Arteries/Arterioles/Capillaries/Venules/Veins

The pulmonary vascular system comprising all vessels that transport blood to and from the lungs for gas exchange.

Lymphatic System (Lungs)

Lymphatic vessels associated with bronchial airways and pulmonary vessels that drain interstitial fluid.

Autonomic Nervous System (Neural Control of the Lungs)

Regulates involuntary lung functions through sympathetic and parasympathetic divisions.

Sympathetic Nervous System (Lung Effects)

Typically accelerates heart rate, constricts certain vessels, relaxes bronchial smooth muscle, and raises blood pressure.

Parasympathetic Nervous System (Lung Effects)

Typically slows heart rate, constricts bronchial smooth muscle, and increases glandular activity.

Bronchial Blood Supply

Systemic circulation via bronchial arteries that nourishes the walls of the bronchi and other conducting airways.

Mediastinum

Central compartment of the thoracic cavity containing the heart, great vessels, trachea, and esophagus.

Pleural Membranes

Two layers (visceral and parietal) with a pleural space between them that encase the lungs.

Diaphragm

Primary muscle of inspiration; separates the thoracic and abdominal cavities and flattens to increase thoracic volume during inhalation.

Accessory Muscles of Inspiration

Muscles such as external intercostals, scalenes, sternocleidomastoid, pectoralis major, and trapezius that assist in increasing thoracic volume during deep or labored inspiration.

Accessory Muscles of Expiration

Muscles including rectus abdominis, external/internal obliques, transversus abdominis, and internal intercostals that assist active expiration.