Comparative Respiratory Anatomy

Comparative Respiratory Anatomy

• Segments of the respiratory system include the nasal cavity, pharynx, larynx, trachea, bronchi, and lungs.
• Respiratory tract divisions based on immune defenses: conductive, transitional, and gas exchange.
• Conductive system immune defense: mucociliary clearance.
• Transitional system immune defense: clara cells.
• Gas exchange system immune defense: intravascular pulmonary macrophages.
• Particles are trapped in the upper and middle respiratory passages through deposition.
• Trapped particles are removed through clearance.
• There are differences between deposited and trapped particles in the upper and middle respiratory passages, called retention.
• Nasal cavity boundaries: dorsal, lateral, and ventral. Also, nasal bone, premaxilla, maxilla, and palatine; rostral and caudal boundaries; nostrils and posterior nares or choanae; apertures of pharynx.

Additional Respiratory Anatomy

• Nasal cavity has meatuses (superior, middle, inferior, and common nasal meatuses).
• Nasal septum separates the nasal cavity.
• Pharynx is a common passageway for digestive and respiratory tracts.
• Larynx is the voicebox, and has a slit-like opening (rima glottidis).
• Epiglottis prevents aspiration pneumonia.
• Trachea has concentric layers (fascia propria, cartilaginous ring, fibroelastic layer, muscular layer, mucus membrane layer). Hyaline cartilage is in tracheal rings.
• Trachea bifurcates at the carina.
• Bronchi branch into bronchioles and alveoli.
• Diffusion of oxygen and carbon dioxide happens in alveoli.
• Larynx functions in voice production (phonation).
• Chemoreceptor cells in nasal epithelium perform olfaction.
• Olfactory nerve (CN1) sends signals to the brain.
• Lungs have an apex and base, and dorsal and ventral borders.
• The right lung has an intermediate or accessory lobe.
• Lobes of the right lung: apical, cardiac, diaphragmatic, and accessory.
• Lobes of the left lung: apical, cardiac, and diaphragmatic.
• Thoracic cavity walls have a diaphragm, which separates the thoracic and abdominal cavities.
• Structures that pass through the diaphragm include the caudal vena cava, aorta, cisterna chyli, esophagus, vagus nerve, and esophageal branch of gastric artery.
• Mediastinum is a potential space between lungs.

Further Respiratory Anatomy

• The pleura and peritoneum are serous linings of the thorax and abdomen.
• Nasal conchae (turbinates) are ethmoid and maxilloturbinates.
• Larynx prevents foreign body aspiration and regulates air volume.
• Laryngeal cartilages: paired (arytenoids, corniculates, cuneiforms) and unpaired (cricoid, epiglottic, and thyroid).
• Structures at the entrance of the laryngeal aperture (aditus): epiglottis, arytenoids, and ary-epiglottic folds.
• Vestibule is the bounded area of the larynx.
• Extrinsic muscles of the larynx include the sternothyrohyoid, thyrohyoid, and hyoepiglottic muscles.
• Vocal cord tensioning muscles include cricothyroid. Rima dilation muscle: dorsal cricoarytenoid. Rima closing muscles: lateral cricoarytenoid, transverse arytenoid, and ventricular (and vocal).
• Types of lungs based on secondary lobules. (cattle, sheep, goat, pig, monkey, dog, cat, horse) characteristics include well developed, absent, or incomplete development.
• Fetal lungs are smaller, pale gray, and do not crepitate. Normal lungs are soft, spongy, crepitate, bright pink, and float in water.
• Cattle, ox, sheep, pig, and dog lungs are often divided into lobes by fissures.

Additional Details

• Different parts of the parietal pleura (costal, mediastinal, and diaphragmatic) reflect into the diaphragm.
• Right lung is larger than left in dogs and divided into four lobes.
• Horse lung has an intermediate lobe but no deep fissure.

This quiz explores the segmentation and functions of the respiratory system, including various structures such as the nasal cavity, pharynx, and lungs. It also discusses immune defenses within different divisions of the respiratory tract. Test your knowledge on the anatomy and functioning of respiratory structures.