exam 2: avian Flashcards
How is the avian ventilatory system different from the mammalian?
-It is about 70% more efficient, open flow through circuit, exchanging in both exhalation and inhalation
-No diaphragm
-Air sacs: move air, responsible for ventilation, no gas exchange occurs at the air sacs
-Deoxygenated blood and oxygenated blood flow opposite of one another and allow for countercurrent exchange (increases gradient for more gas exchange) and there is also cross current exchange
-Psittacine (parrot) sinuses: only one sinus (infraorbital sinus) with lots of diverticula
-no deadspace (like bronchi up in mammals) helps for efficiency
-Lungs are non-expansive
Nasal cavity
an area within the upper beak that houses the tissues (conchae) covered with olfaction nerve endings, blood vessels, and mucus secreting cells
Trachea
a tube that transports air from the larynx to the lungs and vice versa, supported by complete rings of cartilage; elongated in some birds like the wooping crane
Cervical air sac
one of a pair of thin walled membrane on either side of the neck that fills with air coming from the abdominal and thoracic air sacs
Clavicular air sac
a ballon like membrane that fills with air and extends into the hollow spaces inside the sternum and each humerus
Lung
a mass of tiny interconnecting air tubes that interwines with a bed of small blood vessels (capillaries); allows oxygen from the air to pass into the blood and carbon dioxide from the blood to move into the air destined for exhalation
Anterior thoracic air sac
one of a pair of thin walled membranes that stores air on inhalation and distributes ito to the lungs on exhalation so that birds get oxygen rich air through the lungs continuouslt
What air sacs do birds have?
9 total air sacs
1) Cervical air sacs (pair)
2) Interclavicular air sac (one)
3) Anterior thoracic air sac (pair)
4) Posterior Thoracic Sac (pair)
5) abdominal air sac (pair)
Syrinx
a birds sound-producing organ, formed by modifications of the tracheal rings with membranes stretching between the rings in songbirds, extending into the bronchi and branched which allows some species to sing two notes simultaneously
Bronchi
tubes that carry air to the lungs and air sacs formed as the trachea splits into two and connect to the lungs, branching further to connect with air sacs
Psittacine infraorbital sinus
only have one sinus that has lots of diverticula
makes treatment challenging because infection can be spread evenly and makes it hard to drain easily
access areas through drilling through the skill, very difficult
attached through the the cervicothoracic air sac (most cranial, part of the upper respiratory system)
What air sac is the infraorbital sinus in psittacines attached to?
the cervicothoracic air sac of the upper respiratory system
Do birds have deadspace?
NO
How do birds rely on drawing in air without a diaphragm?
they expand their rib cage, they do not have a diaphragm.
Bird inhalation
air leaves the lungs
Bird exhalation
air enters the lungs
Do air sacs play a direct role in gas exhange?
NO, it brings air into the bellow and allows it to be stored until exhalation, allows a continuous stream of air to pass through the lungs in a one-way flow system
connect to pneumatic bones and remove excess heat as the bird breathes.
Posterior air sacs
expand on inspiration
Anterior air sacs
contract on expiration
Path of the avian breathe
1) Inhalation, travels down trachea, into left or right bronchus, into the lung, and into the posterior thoracic and abdominal air sacs
2) Exhalation, abdomen contracts and forces air out of the abdominal sacs and into the lungs, air passes through peribronchi and capillaries where they exchange CO2 and O2
3) Inhalation, the stale air is forced from the lungs to the interclavicular, cervical, and anterior thoracic air sacs
4) Exhalation, air driven out to trachea and passes out of the nostrils
Air sacculitis
inflammation of the air sacs, hard to treat because air sacs are really thin, approx one cel layer thick
What is special about passerine respiratory systems
it is divided, left and a right side
Birds (aves)
-Feathered
-Winged
-Bipedal
-Warm-blooded (endothermic, homeothermic)
-Egg-laying,
-Vertebrate
-Toothless
Bird integument
thin and fragile
three layers (epidermis, dermis, and subcutaneous later)
few muscle attachments in the skin of birds
Numerous attachments to periosteum in the distal limbs (skin directly on bone)
Beak
thickened stratum corneum (calcium phosphate and hydroxyapatite)
continuously worn but supplied by constant growth from the germinal epithelium, analogous to horse’s hoof
Bill tip organ
contain specialized herbst’s corpuscles for recognition of food, very prominent in the dabbling waterfowl
Uropygial gland
the largest cutaneous gland in birds, dorsal tail base, bilobed, holocrine
secretes oily substance that is spread over feathers (for waterproofing, antimicrobials, and maintaining proper feather pliability)
What are the functions of feathers?
Flight, insulation, waterproofing, and display
Flight feathers
found in the wings (reminges) and tail (rectrices)
Reminges
flight feathers covering the wings
Rectrices
flight feathers covering the tail
Contour
the feathers forming the bird’s outer body covering, including the flight feathers and the overlapping body feathers that produce the bird’s smooth aerodynamic shape.
Molting
feather loss and renewal
Continuous in psittacines, seasonal in most other orders
New growth=pin or blood feather
Controlled by thyroid, photoperiod, and other factors
Pin/Blood feather
new feather growth, vascular and nervous bundle in rachis, painful and prone to hemorrhage if broken
Avian muscoskeletal system
light weight bones
variable pneumatized (air-filled), connected to the respiratory system
fused skull with no suture lines
variable number of cervical vertebrae (some up to 35)
flattened ribs and keeled sternum for pectoral muscle attachment
Numerous fused and renamed bones
What bones are fused in birds?
1) Tarsometatarsus (fused tarsus and metatarsus)
2) Tibiotarsus (tibia and proximal tarsal bones)
3) Pygostyle= fused last few caudal vertebrae
4) Pevlic girdle: some lumbar, caudal, ileum, ischium, and pubis (Ridge is synsacrum-lumbar vert, sacrum, and pelvis)
5) Spinal column: ridged back
6) Keeled sternum: only flight birds
7) Furcula: fused clavicles (wish bone)]
8) Carpometacarpus
9) only three digits on manus
Synsacrum
the ridge on the pelvic girdle of avians from fused vertebrae (primarily lumbar)
Pectoral girdle
furcula, coracoids, scapula articulations, forms the triosseal canal
strong and prevent chest collapse during flight and allow for flight muscle attachments
Uncinate process
7 ribs that each have this projections, strength to the body wall
What muscles allow for flight?
1) Supracoracoid- upstroak
2) Pectoralis - downstroak
3) Back bones
4) Brachium muscles
5) antebrachium muscles
What bone is pneumonized in birds ?
Humerus, shows up black in radiographs (specifically on Psittacines, some species have more bones that are pneumatized)
Medullary bones
include tibia, femur, pubic bones, ribs, ulna, toes and scapula. Act as an important source of calcium when eggs are laying eggs. Hen mobilizes calcium from her bones.
Pneumatic bones
important in birds for respiration. Hollow bones which are connected to the respiratory system and make them able to breath. Include the skill, humerus, clavicle, keel, pelvic girdle, and the lumbar and sacral vertebrae
How do medullary bones tend to break?
they shatter like glass, very sharp because of spicules. blow into pieces when fractured
Triosseal foramen
the foramen formed between the articulation of the furcula, scapula, and coracoids
the tendon of the supracoracoideus muscle passes through this fossa for attachment to the dorsal part of the humerus, responsible for the upstroke of the wing
Coracoid bone
functions to prevent the chest from collapsing when the bird flaps its wings.
common fracture when birds hit the window
fractures are hard to diagnose because they are buried in the pectoral muscles
What does it mean when birds are uricotelic
uric acid is the end product of their nitrogen metabolism
