Avian Anatomy & Physiology Flashcards
a protein necessary for the production of scales, feathers and the outer sheaths of beaks and claws
Keratin
dermal structures innervated by smooth muscle to help the regulation of heat in birds
Feather Follicles
the one major skin gland possessed by most birds that secretes an oily substance used to clean and waterproof feathers
Uropygial (Preen) Gland
the one major skin gland possessed by most birds that secretes an oily substance used to clean and waterproof feathers
Preening
Claw types vary based on what 2 things?
- Perching habits
- Method of procuring food
long, sharp, rounded bird claws used to catch and kill prey
Talon
the tiny opening at the base of the feather where it inserts into the skin and is how a new, developing feathers receive nourishment from blood vessels
Inferior Umbilicus
the tiny opening on the feather shaft where the webbed part of the feather begins and gives rise to an afterfeather in some species
Superior Umbilicus
an accessory feather the provides additional insulation to retain body heat
Afterfeather
the round, hollow, semitransparent portion of a feather that extends from the inferior umbilicus to the superior umbilicus
Calamus (the quill)
the main feather shaft
Rachis
the flattened part of a feather that appears weblike on each side of the rachis and consists of numerous barbs
Vane
slender closely spaced structures on the vane of the feather that give rise to barbule
Barb
structures of the feather that have rolled edges and tiny hooklets
Barbules
tiny hooklets that interlock each barb with and adjacent one in order to form a tightly linked and flexible web
Hamuli
the type of feather that covers a bird’s body and constitute the flight feathers of the wings and tail
Contour Feathers
flight feathers in the wing
Remiges
tail feathers
Retrices
small contour feathers around the external ear openings and improve a bird’s hearing ability
Auricular Feathers
the type of feather that provide insulation, provide flexibility for the movement of the contour feathers and help with buoyancy in water birds
Semiplume Feathers
the type of feathers that are soft and fluffy, lack a true shaft, barbules and hooklets on their barbs, and function as insulation
Down Feathers
the type of feathers that have a bare shaft lacking barbs on the majority of their length except the tip and contain sensitive nerve endings that receive pressure and vibration sensations from slight movements of the contour feathers
Filoplume Feathers
modified contour feathers with a stiff rachis, a few barbs at the base and function to serve a bird’s sense of touch
Bristles
the type of feathers that grow continuously at the base and disintegrate at their tip in order to create a waxy powder that is spread throughout the rest of the plumage to clean it and provide waterproofing
Powder Down Feathers
bare areas of skin on the body of birds that contain no feathers
Apteria
specific tracts from which feathers originate on the body of birds
Pterylae
List the 8 types of pterylae
- Caudal
- Humeral
- Alar
- Central
- Spinal
- Femoral
- Crural
- Caudal
a weakened area on the feather vane where the barbs lack barbules caused by interrupted blood flow to the feather during its growth phase
Fault Bar (Stress Bar)
the process of feather replacement that occurs once to several times a year depending on the species
Molting
the type of molting in which one or two pairs of flight feathers are molted at a time so that a bird can still fly adequately
Symmetric Feather Replacement
an epidermal covering that covers a newly emerging feather
Periderm
Give 4 characteristics unique to the avian skeleton that allow for flight
- Reduction in # of bones
- Fusion of bones to form plates > provides strength + simplifies movements
- Reduction in bone density
- Loss of internal bone matrix
two small moveable bones that the lower bill hinges on
Quadrates
List 2 ways the avian skull is adapted for flight
- Thinner than other animals
- Jaws extend into keratinized bill > instead of heavy teeth
the size of the bird’s mouth when open
Gape
protective bony plates that border the eye sockets
Sclerotic Ring
In what 2 ways does the avian vertebral column differ from other animals?
More > cervical + coccygeal vertebrae
Less > thoracic, lumbar, sacral vertebrae
How is the avian cervical vertebrae different than that of mammals? Give 3 ways
- Atlas has 1 condyle instead of 2
- More cervical vertebrae
- Special connecting surfaces for neck flexibility
a projection on one rib that overlaps the adjoining rear rib to strengthen the rib cage of birds
Uncinate Process
a light, strong, bony plate that fuses with the pelvis to provide a stiff framework for support of the legs and acts as a shock absorber when the bird lands to protect the legs and backbone from injury
Synsacrum
The structure formed from the fusion of several distal lumbar vertebrae, sacral vertebrae, and the first few coccygeal vertebrae
Synsacrum
the structure that supports the tail feathers and is formed by the fusion of the distal coccygeal vertebrae
Pygostyle
List the 2 functions of the avian sternum
- Protects chest cavity from injury
- Point of origin for flight muscles
a large bony ridge on the sternum of strong fliers to which the flight muscles attach, but is missing entirely in flightless birds
Keel
What 3 bones make up the pectoral girdle?
- Coracoids
- Scapulae
- Clavicles
the bones of the pectoral girdle that help protect the sternum during the contraction of flight muscles
Coracoids
the bones of the pectoral girdle that help protect the rib cage and are positioned along the backbone
Scapulas
the bones of the pectoral girdle that keep a bird’s shoulders separated and are positioned outward/forward from the body
Clavicles
a depression on each side of the pectoral girdle that forms a joint with the wing
Glenoid Cavity
What is commonly injured when birds collide with glass windows or doors?
Pectoral Girdle
a structure on the humerus that acts as an attachment site for wing muscles
Pectoral Crest
Explain the difference in avian humerus length
Short > birds that rely on flapping flight
Long > birds that glide and soar
weight-bearing bone in birds and acts as an attachment point for the secondary flight feathers
Ulna
the bird bone that originates in the wrist and carries the feathers important for steering
Alula Bone
The first finger in avian species
Alula Bone
feathers important for steering
Alula Feathers
the bird bones that support the primary flight feathers with help from the metacarpals
2nd and 3rd Fingers
a lightly vascularized web of skin extending from the shoulder to the wrist that provides elasticity to the wing and assists in the aerodynamics of flight
Patagium (Propatagium)
What 3 bones make up the avian pelvic girdle?
- Ileum
- Ischium
- Pubis
Which part of the pelvic girdle is not fused and why?
Distal end
Allows for egg laying
the crests on the femur where the leg muscles attach
Greater and Lesser Trochanters
This joint projects forward when standing to help keep the lower leg under the bird’s center of gravity
Stifle Joint
a single, elongated bone that makes up the hock in birds
Tarsometatarsus
the bottom of the bird’s foot that is surrounded by 2-4 toes
Metatarsal Pad
bird species with 3 toes facing forward and 1 facing backward
Anisodactyl
bird species with toes 2 and 3 facing forward and toes 1 and 4 facing backward
Zygodactyl
How do you reference the digits in birds?
Numbering system based on the # of joints the digit has
muscle fibers that are thick, have a low supply of blood and myoglobin, and must use stores of glycogen to sustain muscle contraction for short periods of time
White Fibers
muscle fibers that are thinner and use their rich supply of blood, fat, myoglobin, and mitochondria to sustain muscle contractions for long periods
Red Fibers
List the 4 actions/counteractions of the wing muscles
- Elevating/Depressing the leading edge of the wing
- Pulling the wing Forward/Backward
- Extending/Flexing the wing
- Controlling movement of alula bone
What are the 2 most prominent muscle pairs in birds?
- Pectoralis
- Supracoracoideus
the wing muscle that originates on the sternum, inserts on the underside of the humerus, and depresses the wing when it contracts to cause the downstroke
Pectoralis
the wing movement caused by contraction of the pectoralis muscle
Downstroke
the wing muscle that originates on the sternum, turns into a tendon that passes through the glenoid cavity, inserts on the humerus, and elevates the wing when it contracts to cause the upstroke
Supracoracoideus
the wing movement caused by contraction of the supracoracoideus muscle
Upstroke
when a bird bends its legs to stand on a branch, the tendons also bend and pull the toes closed around the branch
Perching Reflex
the muscle located on the dorsal side of a chick’s head that develops during the embryonic stage, is needed to help a chick break out of its shell, and rapidly atrophies after exiting the shell
Hatching Muscle
Give the 3 possible eye shapes in birds
- Round
- Flat
- Tubular
Which control centers in the avian brain are large?
- Vision
- Hearing
Give the 3 layers of tissue in the avian eye
- Fibrous Tunic
- Uveal Tunic
- Neural Tunic
the layer of the avian eye that consists of the sclera in the back, the cornea in the front, and a sclerotic ring at the transition point between the two
Fibrous Tunic
small bones that reinforce the transition point between the sclera and cornea in avian eyes
Sclerotic Ring
the layer of the avian eye that is vascular and pigmented, and consists of the choroid in the back, the iris in the front, and the ciliary muscles
Uveal Tunic
the layer of the avian eye that consists of the retina
Neural Tunic
What type of muscles are in the iris of birds? Why?
Striated muscles > voluntary control over pupil size
a thin, transparent membrane consisting of specialized epithelial cells that brush moisture over the eye from the nasal corner laterally and contain striated muscles
Nictitating Membrane
a highly vascularized, ribbonlike structure in bird eyes that attach to the retina, floats in the vitreous humor, and distributes nutrition to the eye
Pecten
Nocturnal birds have a higher concentration of (cones/rods).
Rods
Give 3 anatomic features that give birds higher visual acuity
- Retina is only lightly vascularized
- Retina has twice as many photoreceptor cells as other vertebrates
- Each cone has only 1 connection to a bipolar nerve cell
funnel-shaped area containing a high concentration of cones and has the sharpest vision
Fovea
Which type of birds have an additional fovea besides the fovea centralis? Where is it?
Diurnal birds have a temporal fovea too
Which species of birds can see UV light?
Diurnal species
an opening that funnels sound into the eardrum and is bordered with special auricular feathers that protect the ear during turbulent flight, while still allowing sound to pass through
External Ear
the separation of the external ear and the middle ear
Tympanic Membrane
the chamber of the avian ear that contains the columella and acts as a funnel to transmit sound into the cochlear window
Middle Ear
the single bone in the middle ear of birds that acts as a funnel to transmit sound and connects to the inner ear
Columella
the separation between the middle ear and the inner ear and protects the inner ear from pressure damage
Cochlear Window
the chamber of the avian ear that functions to maintain balance and equilibrium, as well as converts sound waves into nerve impulses that are sent to the brain for processing
Inner Ear
the structure of the inner ear that converts sound waves into nerve impulses that are sent to the brain for processing
Cochlea
the flap of skin at each external ear opening that helps to funnel the sound into the ears
Operculum
What unique feature of the operculum helps with vertical location of sound in nocturnal owls?
Asymmetric - one is slightly above the midpoint of the eye and one is slightly below it
List the 2 types of sensory nerve endings on the skin of birds
- Grandry’s Corpuscle
- Herbst Corpuscle
a type of avian tactile nerve ending found in groups in the tongue and palate of species that dig for food
Grandry’s Corpuscle
a type of avian tactile nerve ending that is very sensitive to the slightest feather movement and are found in the mouth, cloaca, legs, wings, uropygial gland, and the bases of many feathers
Herbst Corpuscle
a pouch created by an expansion of the esophagus in birds that functions to store, lubricate, and regulate the passage of food
Crop
List the 3 types of crops
- Dilation of the esophagus
- Single pouch
- Double pouch
What are the 2 components of the bird stomach?
- Proventriculus
- Ventriculus
the component of the bird stomach where chemical digestion begins
Proventriculus
the component of the bird stomach consisting of distinct bands of striated muscles that work to grind food components such as bones, scales, and nuts
Ventriculus
paired sacs located at the junction of the small and large intestines in some species of birds that function to assist in water reabsorption and the bacterial fermentation of cellulose
Ceca
Give the 3 sections of the cloaca
- Coprodeum
- Urodeum
- Proctodeum
the section of the cloaca that receives excrement from the intestine
Coprodeum
the section of the cloaca that receives discharge from the kidneys and genital ducts
Urodeum
the section of the cloaca that stores the excrement
Proctodeum
the organization of waste products that consist of a dark fecal matter center surrounded by a ring of urates
Mute
the muscular opening through which mute is eliminated
Vent
How many chambers does the avian heart have?
4
Adheres to several internal surfaces to keep the heart anchored in place
Pericardial Sac
the vessels that provide blood to the flight muscles and wings and are very large (respectively)
Pectoral + Brachial Arteries
valves at the junction of the iliac and renal veins that steer blood to either the kidneys for removal of metabolic waste or directly to the heart
Renal Portal System
Which type of wave on ECGs are missing in some species of birds?
Q waves
phagocytic avian leukocytes whose rise in number is usually seen with the onset of acute diseases
Heterophils
avian leukocytes whose rise in number is a response to allergic reactions and heavy internal parasite loads
Eosinophils
phagocytic avian leukocytes that act as a body’s second line of cellular defense and indicate tuberculosis and aspergillosis when they increase in number
Monocytes
avian leukocytes that produce humeral antibodies to help fight off infections
Lymphocytes
the opening of the trachea at the back of the tongue
Glottis
two internal nares that open from the nasal chambers in the roof of the mouth
Choanae
Does NOT produce sound like it does in mammals
Larynx
the enlargement of the trachea above the sternum that contains muscles, air sacs, and vibrating membranes to produce sound
Syrinx
What dictates the complexity of avian vocalizations?
The # of muscles in the syrinx
the term for the bronchi once they enter the lung and lose their cartilaginous rings
Mesobronchi
secondary bronchi
Ventrobronchi
the small divisions of the bronchi that are connected to air capillaries
Parabronchi
thin-walled, lightly vascularized, transparent membranes that make up 80% of the total volume of the respiratory system
Air Sacs
List the 9 air sacs in the avian respiratory system
- Cranial (x2)
- Caudal (x2)
- Cervical (x2)
- Abdominal (x2)
- Interclavicular (x1)
Give the 4 functions of avian air sacs
- Reservoirs for air
- Facilitate air diffusion through capillaries
- Thermoregulation
- Provide buoyancy for water birds
______ + _____ are required to transport one pocket of air through the entire respiratory system
2 inhalations + 2 expirations
How is air moved into the lungs?
Pushed
the rapid vibration of a bird’s upper throat patch when they are trying to increase airflow throughout their respiratory system
Gular Fluttering
a heat conservation process in which body temperature is decreased by several degrees and heart rate and oxygen consumption are reduced
Nocturnal Torpor
the structures in nephrons that remove wastes, salt, glucose, gases, and water from the blood
Glomerulus
the structures in nephrons that selectively reabsorb water, salt, and glucose into the blood through capillaries to concentrate waste products for elimination
Tubules
What is the predominant component in avian urine?
Uric Acid
Where is seminal fluid produced in the avian reproductive system?
Tubules
Give the 5 divisions of the avian oviduct
- Infundibulum
- Magnum
- Isthmus
- Uterus (Shell Gland)
- Vagina
the segment of the avian oviduct the possesses folds that grab an ovum as it comes out of the ovary
Infundibulum
the segment of the avian oviduct that secretes layers of albumin around the egg
Magnum
the segment of the avian oviduct that deposits the keratin shell membrane
Isthmus
the large and muscular segment of the avian oviduct that deposits watery albumin, a hard external shell, and pigmentation
Uterus (Shell Gland)
the segment of the avian oviduct that secretes mucus to assist in egg laying and stores sperm for hours to several days
Vagina
a group of eggs that a female bird lays and incubates
Clutch
What are the 2 types of egg layers?
- Determinate
- Indeterminate
egg layers with a specific number of follicles that develop in the ovary and produces a complete clutch once they are laid (even if the eggs are removed)
Determinate
egg layers that can produce more eggs than their normal clutch size and will continue to lay eggs if their eggs disappear
Indeterminate
What is the average incubation temperature?
95 F
the incubation behavior
Broodiness
an area of skin on the lower abdomen where heat is transferred to the egg
Brood Patch
Which sex determines gender of the chick? How are the chromosomes represented?
Females
ZZ = male
ZW = female
List the 4 classifications of newly hatched chicks
- Altricial
- Semialtricial
- Precocial
- Semiprecocial
chicks hatching with their eyes closed and skin bare that require a lot of care before they can leave the nest
Altricial
chicks hatching covered in down, are immobile, may have eyes open or closed
Semialtricial
chicks hatching covered in downy feathers, have their eyes open, are mobile, and leave the nest quickly
Precocial
chicks hatching covered in down, have open eyes, move a short distance from the nest, and are fed by their parents
Semiprecocial
the process of rubbing the beak on rough surfaces to clean them and maintain their shape after a meal
Feak
the trimming and reshaping of beaks and nails to prevent them from becoming too long to eat properly or developing cracks and chips
Coping
degeneration of the bones in the feet
Osteomyelitis
the condition characterized by pad abrasions, abscess formation, and osteomyelitis due to claws becoming too long and sharp
Bumblefoot
a condition in which birds preen excessively, removing most to all of their body feathers, especially on their chest and legs
Feather Picking Disorder
What are the 3 easiest vessels to draw blood from in birds?
- Jugular vein
- Brachial vein
- Medial metatarsal vein
The jugular is most commonly used for venipuncture in what species?
Psittacines
The brachial vein is most commonly used for venipuncture in what species?
Raptors
The medial metatarsal vein is most commonly used for venipuncture in what species?
Waterfowl
when the bird tail moves with each labored breath
Tail Bobbing
the condition in which eggs passing through the oviduct sometimes get lodged
Egg Binding
