Avian Anatomy Review

Vocabulary flashcards covering key concepts in avian anatomy.

Preen gland

Located next to the skin under the contour feathers, it secretes oils to condition and waterproof feathers.

Filoplume feathers

Hair-like feathers associated with sensory receptors, helping to detect feather position and movement.

Patagium

Web of skin extending from the shoulder to the wrist, supporting wing structure and aiding in aerodynamics during flight.

Pectoralis muscle

The large muscle that powers the downstroke of the wing during flight, preferred for intramuscular injections.

Scleral ossicles

Structures located at the junction of the cornea and sclera in an avian eye, providing structural support.

Membranous labyrinth

Part of the inner ear that maintains balance and equilibrium, containing semicircular canals and vestibule.

Crop

An outpouching of the esophagus that serves as a temporary storage site for food.

Bursa of Fabricius

An endocrine gland in birds that influences the production of B lymphocytes for antibody production.

Parabronchi

Structures in the lungs where gas exchange occurs during both inhalation and exhalation in birds.

Testes location in male birds

Located ventral to the cranial pole of the kidney, reducing weight for aerodynamic efficiency.

Talons

Sharp, curved claws adapted for grasping and killing prey, found in birds of prey.

Calamus

The round, hollow part of a contour feather below the webbed part, containing the blood supply during growth.

Pterylae

Areas of skin on a bird where feathers grow, separated by bare areas called apterylae.

Uncinate process

Bony projections extending from the ribs, strengthening the rib cage and aiding respiration.

Atlas

The first cervical vertebra, articulated with the skull by a single condyle, allowing greater head movement.

Synsacrum

A fused structure acting as a shock absorber during landing and providing rigidity for flight.

Wishbone

Also known as the furcula, formed by the fusion of clavicles, it acts like a spring during flight.

Alula

The first finger of a wing, playing a critical role in flight by controlling airflow.

White muscle

Muscle fibers with low blood supply and fewer mitochondria, adapted for short bursts of activity.

Fovea

The area of sharpest vision in the eye, with densely packed photoreceptors for exceptional visual acuity.

Columella

The single middle ear bone in birds that transmits sound vibrations from the eardrum to the inner ear.

Proventriculus

The glandular stomach of birds that secretes digestive enzymes before food moves to the gizzard.

Cloaca

The terminal end of the digestive system where excretion of feces, urine, and eggs occurs.

Mute of feces

Composed of a dark fecal center surrounded by white urates, indicating normal digestion.

Countercurrent heat exchange

System where heat from warmer veins is transferred to cooler arteries, reducing heat loss in cold environments.

Nucleated red blood cells

Characteristic of avian red blood cells, allowing for protein production within the cell.

Heterophils

Avian blood cells equivalent to mammalian neutrophils, involved in the immune response.

Common venipuncture sites in birds

The medial metatarsal, lateral metatarsal, and jugular veins, often used for blood sampling.

Air sacs in avian respiratory system

Composed of three pairs plus one unpaired, facilitating continuous gas exchange.

Rudimentary gonad in birds

The right ovary, which does not develop in most birds, reducing weight for flight.

Magnus layer of oviduct

Secretes layers of albumin around the egg, providing water and protein for the embryo.

Determinate layers

Bird species that lay a specific number of eggs to incubate and won’t lay more if those eggs are removed.

Precocial chicks

Chicks that are covered with downy feathers, have open eyes, and are quickly mobile.

Passeriformes

The order of birds that includes perching birds such as crows, swallows, and songbirds.

Female bird chromosome pattern

ZW, while males have a ZZ pattern.