Avian Flashcards
Avian Skeletal
What are the axial and appendicular skeleton comprised of?
Axial = skull and vertebral column
Appendicular = pelvis and limbs
Avian Skeletal
Explain some attributes of avian bones. (7 marks)
Light and strong.
Reduced number of bones because they are fused together to make the skeleton more rigid.
Bones are fused into single ossifications.
Reduced density.
Thinner bones.
Hollow with air sacs.
No teeth or jaw - beak instead.
Avian Skeletal
What is a keel?
An extension of the sternum (breastbone).
Provides attachment for of flight muscles.
Avian Skeletal
What is the fused collarbone called?
Furcula (wishbone)
Avian Skeletal
What allows a bird to turn their head 180 degrees?
A single occipital condyle articulates with the atlas.
Avian Skeletal
What are sclerotic rings?
Rings of bone found in the eyes.
Avian Skeletal
What does the craniofacial hinge do?
Lies between the upper beak and skull and increases mobility of the beak during feeding.
Avian Skeletal
What is the makeup of the skull?
Bones of the skull are fused to form a rigid but lightweight box.
Within the skull are pockets of air.
Avian Skeletal
What type of joint is the atlas?
Ball and socket joint
Avian Skeletal
How many cervical vertebrae do birds have and why?
13-25 vertebrae.
For flexibility and extension when eating.
Some are fused together for rigidity and flight.
Avian Skeletal
What are Uncinate processes?
Backwards pointing processes that add strength to the ribcage.
They provide attachments for muscles adding strength to the thoracic wall.
Avian Skeletal
What is the Synsacrum?
Fusion of caudal thoracic, lumbar, sacral, and caudal vertebrae.
10-23 vertebrae.
Acts as a shock absorber for flight and landing.
Supports the pelvic girdle.
Avian Skeletal
What are the ribs like?
First few ribs are short and incomplete.
Avian Skeletal
What is the Pygostyle?
Fusion of the last vertebrae.
Provides support for the tail feathers and rudder.
Avian Skeletal
What bones are the Pectoral girdle comprised of?
Coracoid, Scapulae, Clavicles.
Avian Skeletal
What is the pelvic girdle movement like?
Rotates backwards and forwards for perching and locomotion.
Avian Skeletal
What does the pelvic girdle do?
Extensive fusion of bones of the pelvic region provide support for the legs in order to deal with stress of take off and landing.
Avian Skeletal
What is the pelvic girdle made up of?
Ischium, Pubis, Ilium all fused.
They are rigidly attached to the synsacrum at the ilium.
Avian Skeletal
What is the use of the pelvic limbs?
Fused distally to absorb shock of take off and landing.
Used for swimming, catching prey, and wading.
Covered by feathers and skin to the level of the inter tarsal joint and covered in scales below that.
Avian Skeletal
Explain the attributes of the phalanges.
4 digits for flexion and extension.
Birds walk on their toes.
Avian Skeletal
What are the wings comprised of?
Humerus, Radius, Ulna, Carpal bones, Carpi-metacarpus and 3 digits.
Avian Skeletal
What are the 4 main types of wings?
Elliptical = short broad wings to avoid stalling and rapid beat in flight.
Broad = allows to soar at low speeds.
Long and Narrow = pointed wings with no slots to allow soaring at high speeds.
Tapered = no wing slits to allow flight with rapid wing beats at high speeds.
Avian Skeletal
What is the difference between medullary and pneumatic bones?
Medullary are long bones that act as a store for calcium for egg production.
Pneumatic are hollow bones fused together to create a light body weight for flight. Allows gas exchange using air sacs and aids flight at high altitude.
Avian Skeletal
What are the attributes of the humerus?
Short bone
Lies against the body wall when wing is folded.
Avian Skeletal
What are the attributes of the radius and ulna?
Long bones.
Lie parallel to each other.
Bones do not twist.
Ulna is bigger and lies caudally.
Avian Skeletal
Explain the attributes of the digits.
3 digits.
The feathers attached to the 1st digits are raised during flight to prevent stalling at slow speeds.
Avian Skin
What are the attributes of the skin?
Skin has epidermis and dermis.
Epidermis outer layer is thin.
Scales, feathers, outer layer of beak are made up of keratin.
Avian Skin
What is the preen gland?
Don’t have sweat glands but do have a preen gland on upper surface of tail.
Preen gland is an oily fatty substance that spreads through feathers to clean and waterproof them.
Avian Feathers
What are the function of feathers?
Flight.
Protection.
Thermoregulation.
Camouflage
Communication (courtship)
Avian Digestive System
What are the components of the GI tract?
Mouth and beak, Tongue, Saliva, Crop, Ventriculus, Stomach, Enzymes, Small Intestine, Large Intestine, Cloaca
Avian Digestive System
What is the mouth and beak used for?
Initiates mastication process and has salivary glands to help lubricate food.
Used for tearing meat, cracking seeds, straining feeding particles, spearing and probing.
Avian Digestive System
Where is the oesophagus located and what is it lined with?
Starts at the mouth and ends at the pro-ventriculus.
Lies to the right side of the neck.
Lined with stratified epithelium contains mucous glands.