Respiratory Anatomy Flashcards
Upper respiratory tract
Nostrils, nasal cavity, pharynx, larynx
Lower respiratory tract
trachea, lungs
External nostrils
Externally covered by skin, cartilage on medial, dorsal and ventral surface. Margins of nostrils are mobile.
Nasal cavity
Extends from external nostril -> internal nostrils (choanae) at caudal extremity of hard palate
Nasal septum
median partition of nasal cavity = cartilage rostrally, bone caudally
Concha (turbinate)
bony scroll protruding into nasal cavity - covered with mucosa. Defines the passageways for air = meatuses.
Paranasal Sinuses
Air filled cavities the skull bones - arise from nasal cavity and retain very narrow connections with it
Nasal cavity functions and histology
Nasal cavity modifies incoming air. Air warmed as it passes over vascular mucosa. Humidified by vaporization of tears and serous nasal secretions. Cleansed by contact with secretions from mucous glands - mucus moves towards pharynx and is swallowed. Mucosa has ‘typical respiratory epithelium’ - except olfactory area.
Typical Respiratory Epithelium (TRE)
Ciliated, pseudostratified columnar epithelium with goblet cells. Lies on CT with numerous blood vessels and glands. Lines most of nose and respiratory tract.
Pharynx
Common chamber of digestive and respiratory tracts
Larynx
Connection between pharynx and trachea. Made of a number of individual cartilages, joined by ligaments, membranes and associated muscles.
Function of Larynx
Regulation of airflow. Prevention of inspiration of food. Vocalization.
Trachea
C-shaped cartilage rings interspersed with annular ligaments. Gap in rings closed by elastic connective tissue and trachealis muscle dorsally. Bifurcates into 2 bronchi dorsal to heart.
Terminal bronchiole
last component of conducting airways (no gas exchange)
Respiratory bronchiole
Smallest bronchiole. Connect conducting passages to primary structures involved in gas exchange between air and blood - outpouchings called alveoli.
Alveolus
functional unit of lung. Single layer flattened epithelial cells. Form groups called alveolar sacs, which are the end of the respiratory tree. Gas exchange occurs readily across the thin fragile wall of the alveoli to capillaries on the external surface.
Lung anatomy
Lungs - paired. Right lung > Left lung. soft organs - change in size and shape depending on stage of respiration. Subdivided into lobes according to divisions of bronchi (air supply).
Hilus
site where structures enter or exit lung (bronchi, arteries, veins, nerves)
Patterns of lobation
Left lung - cranial, caudal. Right lung - cranial, middle, caudal.
Lobules
Internal subdivisions of lungs (lobulation). -> marbled surface appearance. The extent of lobation and lobulation can be used to differentiate lung tissue between species.
Thoracic cavity
Space enclosed by ribs, vertebrae, sternum, diaphragm. Contains lungs in their pleural sacs + central mediastinum. Lungs and thoracic wall covered by Pulmonary pleura. Two pleural sacs. Maintains negative pressure. Each sac has a pleural cavity.
Mediastinum
part of the thoracic cavity between the lungs: heart, esophagus, blood vessels, thymus, trachea.
Pulmonary pleura
thin membrane of simple squamous epithelium and connective tissue
Thoracic cavity - breathing
Lateral surfaces of lungs push against walls of thorax. Medial surfaces push against other thoracic organs.
