Ch.22 The Respiratory System

Respiration

Gas exchange between atmosphere, lungs, blood, tissues.

Functions of Respiratory System

Facilitates gas exchange, sound production, and olfaction.

Upper Respiratory Tract

Filters, warms, and humidifies incoming air.

Lower Respiratory Tract

Conducts air to gas exchange surfaces.

Conducting Zone

Transport air, includes most of respiratory tract.

Respiratory Zone

Site of gas exchange, includes alveoli.

Nose

Primary air passageway during quiet breathing.

Nasal Septum

Divides nasal cavity into right and left portions.

Nasal Cartilages

Support nostrils and prevent collapse during inhalation.

External Nares

Nostrils that open into the nasal cavity.

Nasal Cavity

Space between external and internal nares.

Nasal Vestibule

Contains vibrissae to trap airborne particles.

Cribriform Plate

Roof of nasal cavity with holes for olfactory bulbs.

Hard Palate

Anterior floor of nasal cavity, formed by bones.

Soft Palate

Muscular flap that blocks nasal cavity during swallowing.

Concha

Bony ridges that create turbulence in nasal cavity.

Superior Nasal Concha

Top bony ridge in nasal cavity.

Middle Nasal Concha

Middle bony ridge in nasal cavity.

Inferior Nasal Concha

Bottom bony ridge in nasal cavity.

Vibrissae

Coarse hairs that trap large airborne particles.

Olfactory Receptors

Detect olfactory stimuli in nasal cavity.

Alveoli

Air

Meatuses

Air passageways between nasal concha.

Internal nares

Boundary between nasal cavity and pharynx.

Pseudostratified columnar epithelium

Secretes mucus and antimicrobial substances.

Paranasal sinuses

Hollow cavities in facial bones for mucus production.

Nasopharynx

Superior pharynx section with pharyngeal tonsils.

Oropharynx

Middle pharynx section with palatine tonsils.

Laryngopharynx

Inferior pharynx section leading to larynx and esophagus.

Larynx

Voice box protecting the glottis.

Glottis

Narrow opening for air between pharynx and larynx.

Epiglottis

Elastic cartilage flap covering glottis during swallowing.

Thyroid cartilage

Large hyaline cartilage forming larynx walls.

Laryngeal prominence

Anterior surface of thyroid cartilage, known as Adam's Apple.

Cricoid cartilage

Supports larynx with expanded posterior section.

Arytenoid cartilages

Anchor vocal cords, articulate with cricoid cartilage.

Cuneiform cartilages

Curved cartilage in folds near arytenoid cartilages.

Corniculate cartilages

Assist in glottis function and sound production.

Vestibular ligaments

Connect thyroid and arytenoid cartilages.

Vocal ligaments

Located within vocal folds, essential for sound.

Vocal folds

House vocal ligaments, produce sound.

Palatine tonsils

Located in oropharynx, protect against pathogens.

Lingual tonsils

Located at the back of the tongue.

Thyrohyoid membrane

Connects thyroid cartilage to hyoid bone.

Vocal folds

Vibrate to produce sound; also called vocal cords.

Vestibular folds

False vocal cords; prevent foreign object entry.

Trachea

Windpipe; conducts air to lungs, 2.5 cm diameter.

Mucosa

Pseudostratified epithelium with goblet cells and cilia.

Submucosa

Connective tissue with exocrine glands and blood vessels.

Adventitia

Anchors trachea; prevents overexpansion.

Tracheal cartilages

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Trachealis muscle

Smooth muscle that adjusts trachea diameter.

Site of Carina

Cartilage supporting trachea branching into bronchi.

Bronchial Tree

Branching pattern of bronchi and bronchioles.

Primary bronchi

Branch from trachea; right and left lung transport.

Secondary bronchi

Right bronchus has three; left has two branches.

Tertiary bronchi

Branch from secondary bronchi; form cartilage plates.

Bronchioles

Microscopic passageways delivering air to lobules.

Terminal bronchioles

Last conducting zone branch; supply pulmonary lobule.

Respiratory bronchioles

First respiratory zone branch; lead to alveoli.

Alveolar ducts

Connect multiple alveoli; form alveolar sacs.

Bronchodilation

Smooth muscle relaxation; increases airway diameter.

Bronchoconstriction

Smooth muscle contraction; decreases airway diameter.

Gross Anatomy of Lungs

Paired thoracic organs with 150 million alveoli.

Apex of lungs

Narrow top region of the lungs.

Base of lungs

Wide bottom region in contact with diaphragm.

Right lung

Three lobes; divided by horizontal and oblique fissures.

Left lung

Two lobes; divided by a single oblique fissure.

Cardiac notch

Curvature in left lung for heart positioning.

Pulmonary hilum

Indention allowing passage of bronchi and vessels.

Root of the lung

Dense connective tissue fixing lung structures.

Pulmonary arteries

Transport deoxygenated blood from heart to lungs.

Pulmonary veins

Carry oxygenated blood from lungs to heart.

Costal surface

Lung surface facing the rib cage.

Mediastinal surface

Lung surface facing the mediastinum.

Diaphragmatic surface

Lung surface facing the diaphragm.

Alveolar epithelium

Simple squamous epithelium lining alveoli.

Type I pneumocytes

Squamous cells forming alveolar walls.

Type II pneumocytes

Cuboidal cells producing surfactant in alveoli.

Surfactant

Oily secretion preventing alveolar collapse.

Atelectasis

Condition of a collapsed lung.

Alveolar macrophages

Cells that phagocytize debris in alveoli.

Pulmonary capillaries

Capillaries that respond to alveolar oxygen levels.

Respiratory membrane

Barrier for gas exchange between air and blood.

Pleura membranes

Serous membranes surrounding the lungs.

Parietal pleura

Lines thoracic cavity and diaphragm.

Visceral pleura

Covers the external surface of lungs.

Pleural cavity

Space between parietal and visceral pleura.

Pleural fluid

Reduces friction between pleural surfaces.

Respiratory mucosa

Mucosal lining in respiratory passages.

Mucus escalator

Mechanism sweeping debris towards external nares.

Alveoli

Gas exchange surfaces made of simple squamous epithelium.

Pulmonary ventilation

Breathing driven by pressure changes in pleural cavities.

Atmospheric pressure

Force exerted by air mixture; 760 mmHg at sea level.

Alveolar pressure

Pressure exerted by air within alveoli; varies during breathing.

Intrapleural pressure

Pressure in pleural cavity; 4 mmHg lower than alveolar pressure.

Pneumothorax

Condition caused by increased pleural pressure, leading to lung collapse.

Atelectasis

Lung collapse due to pneumothorax or other factors.

Boyle's Law

Volume inversely proportional to pressure; V↑ = P↓.

Inspiratory muscles

Muscles that facilitate inhalation during breathing.