Comparative Anatomy of Larynx and Lungs

organ in the neck region involved in brething, sound production, and protection of the trachea against foreign matter aspiration

jut below where the tract of the pharynx splits into the trachea and esophagus

acts as a sphincter or valve to prevent the entry of foreign matter into the respiratory system; reptiles lack a secondary palate to prevent this

six pieces of cartilage and intrinsic and extrinsic muscles

Muscles: intrinsic are responsible for controlling sound production, and extrinsic are involved in support and position the larynx in the trachea

Cartilage: three unpaired--thyroid, cricoid, epiglottis; three paired-- arytenoid, corniculate, cuneiform

elastic sacs that expand on inhalation and are a site for gaseous exchange situated in the thoracic cavity

• --> elastic sacs that expand on inhalation and are a site for gaseous exchange situated in the thoracic cavity
• --> they develop from the ventral respiratory tract with the larynx located at the top

Climbing perch (anabas scandens): acquired a respiratory diverticulum or muscular sphincter off of the pharynx

Indian siluroid fish (Saccobranchus): acquired long diverticulum leading into an internal air reservoir--this contains no valves to prevent water entry

muscular sphincter closes in water and opens in times of drought to enable a swallowing of air

most primitive larynx (in polypterus)  functioned as a simple sphincter to prevent the intrusion of foreign matter

the most primitive larynx was found in polypterus and consisted of a muscular sphincter to guard against water entry

African (Protopterus) and Australian (neocaratdus)  lungfish: both possess discrete muscle fibers to draw apart vulvar margins to produce active dilations

have gills for gas exchange in water

lungfish contain lungs derived from the swim bladder; inner surface contains many honeycomb-like cavities supplied with blood vessels where gas exchange occurs

acquired lateral cartilages that form bars on either side of the glottis to which dilator muscles insert

very primitive with few internal septa and possess large alveoli; incomplete septa divide the lung

the trachea stops at lung junction and does not divide into the secondary tubes

Lungs divided by secondary septa that surrounds the very large space where gas exchange happens

there is a very slow diffusion rate in the lungs, which is why most are able to diffuse gases through the skin

possess a cartilaginous ring that gives origins to the dilator muscles and can be found between the glottis and the trachea

aquatic turtles have developed a permeable skin and a modified cloaca to increase the area for gas exchange

lungs are simple, sac-like structures with alveoli in the walls

less respirratory efficiency

many lizards/turtles have more partitions within= more surface area for gas exchange

Cartilaginous ring that gives origin to the dilator muscles and is found between the glottis and trachea

syrinx

syrinx: membranous structure at the lower end of the trachea; where the bird's song is produced (kind of like a voice box)

lungs connected to voluminous air sacs

Tertiary bronchi penetrate lung mass and contain air capillaries in the walls; capillaries have large surface area and come in contact with blood capillaries connected to the heart

no alveoli: they use mesobranhi

cartilaginous ring that gives origin to the dilator muscles and is found between glottis and trachea

phonation

contain many alveoli on the ends of the bronchioles

most developed