Avian Flashcards
Who are the closest relatives to avians?
Crocodiles
What are the two jaw types for avians?
Neognathic & paleognathic
What is a neognathic jaw, and which species have them?
“new jaw”
Greater mobility. Most birds have this jaw
What is a “paleognathic jaw” and which species has it?
“old jaw”
Ratites
What is unique about avian bones
Thin cortex. Hollow with internal struts for strength. Pneumatic bones
Which bones are pneumatic bones in avians, and what does that mean?
Ileum/pubis, humerus, sternum, clavicle, vertebral bones, skull, coracoid
Air sacs extend out into the bones
What is the purpose of the keel, and where is it located?
Mostly in flighted birds. Ventral projection from sternum for muscle attachment. Greater flight ability = greater size
How many cervical vertebrae do avians have?
11-20
Why can birds rotate their heads almost 360?
Atlas only has one condyle, where mammals Atlas has 2
What are the fused coccygeal vertebrae in avians called?
Pygostyle
What is the purpose of the pygostyle in avians?
changes the directed of the feathers. Used for turning left and right
What is the beak made out of?
Keratinized epithelial
T/F beaks/bills stop growing once they reach a certain size
FALSE. Made of keratinized epithelial, so they grow continuously
What is the purpose of the sclerotic ring in avians?
Supports larger eyes
What is unique about avian ribs?
They are rigid (except penguins) & have caudal bone projections that connects the ribs together for strength
What are the rib projections in avians called?
Uncinate process
Which bones are fused in the avian forelimb?
Furcula, carpus, & metacarpus
What are the bones of the avian forelimb?
Coracoid, humerus, radius, ulna, carpus, metacarpus, digits
What is the purpose of the coracoid?
Wing support
Which forelimb digits are the main digits?
2&3
What is digit 1 of the avian forelimb called?
Alula
Which bone is the wishbone?
Furcula
Which bone in avians is the equivalent of the collar bone in mammals?
Furcula (fused collarbones)
What are the rear limbs bones in the avian?
Tibiotarsus, tarsometatarsus, digits
Which bones in the avian rear limbs are fused>
Tibia & fibula (tibiotarsus)
Tarsus & metatarsal (tarsometatarsus)
What are the two main types of digits that avians can have?
Anisodactyl & zygodactyl
What are anisodactyl digits? How are they numbered?
3 forward and 1 back. Digit 1 is rear, 2 is axial, 3 is middle, 4 is abaxial
What are zygodactyl digits? How are they numbered?
1&4 face rear
2&3 face forward
What are the types of contour feathers?
Body feathers
Tail feathers
Flight feathers
What is unique about the pelvic girdle in avians?
Fused, no symphysis. No pelvic floor (distensible for eggs to pass)
Why are “light meat” & “dark meat” different colors?
Light meat: muscles with decreased blood supply and myoglobin. Muscles that are not used as much for that particular bird
Dark meat: muscles with increased blood supply, increased myoglobin, and mitochondria. Muscles that are used more often for that particular bird
What are the two main flight muscles?
Pectoral muscles & supracoracoid muscles
What three bones make up the foreman triosseum?
Furcula, scapula, coracoid
What wing movement are the pectorals responsible for?
Down stroke. Wing moving forward
What wing movement is the supracoracoid responsible for?
Up stroke. Wing moving backwards
Which wing stroke requires more muscle?
Down stroke. pectorals
What is the perching reflex?
Tendons aren’t flexible, so toes flex when thigh muscles tighten. When legs are flexed = toes are flex. When legs are extended = toes open
How many internal cavities does a bird have? What does this mean?
1 coelomic cavity
NO DIAPHRAGM
What cells make feathers?
Epithelial cells with keratin
How many vertebrae are in the synsacrum
7 sacral, 6 caudal vertebrae
Which feathers are tail feathers?
Retrices
Which feathers are flight feathers?
remiges
What is the purpose of contour body feathers?
Gives shape, color, and protection from elements
What is the purpose of semiplume feathers? Where are they found?
Insulation & flexibility. Found deep to contour feathers
What is the purpose of to down feathers? Where are they found?
Insulation. Deep to contour feathers
What is the purpose of filoplume feathers?
Nerve endings (at the root/base) for sensation & knowing feather position
What is the purpose of bristle feathers? Where are they found?
Sensation. Found in face & feet
What are the tracts called where feathers grow?
Pterylae
How many feather tracts do birds have?
7
What is moulting?
Feathers fall out and are replaced
What two types of moulting are there?
Pattern replacement (still can fly during)
Complete replacement (can’t fly until finished)
Which feather is dangerous to cut too short, and can lead to severe blood loss?
Blood feathers
How many chambers does the avian heart have?
- Similar to mammals
What do you have to be careful of when giving birds injections?
Birds have a renal portal system, so you have to inject cranial to the kidneys in order for meds to have systemic effect
Where do mammals have portal systems? Which portal system do avians have that mammals do not?
Mammals have hepatic and brain portal system. Avians have a renal portal system
What is the quill of a feather called?
Calamus
What is the shaft of a feather called?
Rachis
What part of the feather is flattened and weblike?
vane
How does the vane keep its shape?
Linked with barbs, barbules, and hooks
What is unique about avian red blood cells?
Nucleated & oval
What types of cells do avians have instead of leukocytes?
Heterophils
What type of cells do avians have instead of platelets? What makes them different than platelets?
Thrombocytes. nucleated
What is a crop?
Pouch that extends off of the esophagus. Used for storage of food & crop milk to feed offspring
What part of the avian stomach is the glandular portion. What does it do?
Proventriculus. Chemical breakdown of food
What is the gizzard?
Ventriculus. Muscular portion for grinding food
T/F avians only have one cecum
FALSE. Avians have paired cecum for fermentation (similar to horses)
What tracts empty through the cloaca?
GI, urinary, reproductive
What type of liver to avians have?
bilobed
What changes about the avian pancreas depending on diet?
Pancreas size is larger in birds who eat grain
Pancreas size is smaller in carnivorous birds
How much more efficient is the avian respiratory system to the mammal?
10x
What are the primary differences in the avian respiratory system?
No diaphragm. No lung expansion, air sacs have movement through them in body cavity and bones
What is the structure in the mouth that the nares connect to?
Choana
Why do avian tracheas have complete cartilage rings?
The trachea moves out of the way if they swallow something large
What is the voice box in avians called? Where is it located?
Syrinx. Located at the tracheal bifurcation
How many air sacs do avians have? Where are they located?
9
Interclavicular
Cervical x2
Cranial thoracic x2
Caudal thoracic x2
Abdominal x2
What are the primary functions of air sacs?
Function as air reservoir bags for air going into the lungs for pulmonary diffusion.
Thermal regulation via internal evaporation
Buoyancy in water (diving birds & water fowl)
How are diving birds able to stay underwater?
They can change the air content of their air sacs
Where are the lungs located in avians?
Fixed structure on the dorsal aspect of the costal arches
How does gas exchange happen in avian lungs?
Exchanges via cross current and air capillaries. Air goes one direction and blood goes the other
Explain avian respiration
1st inhalation: air goes from airways to caudal air sacs
1st exhalation: air goes from caudal air sacs to lungs
2nd inhalation: air goes from lungs to cranial air sacs
2nd exhalation: air goes from cranial air sacs to trachea & is exhaled
T/F avians have the same air flow as mammals
FALSE. Avains have one way air flow
What is different about avian kidney anatomy?
Divisions are less distinct. No renal pelvis
What organ do birds lack?
Bladder :(
Which portion of the cloaca is responsible for water reabsorption?
Urodeum
Where are the testes found in male avians?
Ventral to cranial portion of kidneys
What causes the vas deferens to change in avians?
if they are sexually mature or not
What is the purpose of the seminal vesicles in avians?
Storage & cooling. Sperm is stored in the seminal vesicles then goes to the urodeum when breeding
Why do birds not have a true penis?
Because there is no urethra
What is unique about avian ovaries?
Only left is fully formed and functioning. Right is vestigial
How often do avians ovulate?
Every day
What hormones control avian ovulation
FSH & LH
Same as in mammals
What are the different portions of the oviduct?
Infundibulum, magnum, isthmus, uterus, vagina
What portion of the oviduct secretes albumin?
Magnum. (Egg whites)
What portion of the oviduct creates the shell membrane?
Isthmus
Which portion of the oviduct has a shell gland that creates the shell portion of the egg?
Uterus
Where is sperm stored in the female bird after breeding?
Vageen
What is a clutch?
Number of eggs laid
What is the difference between determinate and indeterminate clutches?
Determinate: set number of eggs laid
Indeterminate: continuous production. If egg goes missing they will lay another
Which portions of the avian brain are largest? (Regarding senses)
Vision and auditory
Which sense do some avians have almost none of?
Smell
How are birds able to process visual input while flying?
Optic lobes go directly to midbrain
What are the three shapes of eyes birds can have? What is an example of each?
Round (hawks)
Flat (pigeons)
Tubular (owls)
What are tubular eyes important for?
Pupil > retina for night vision
What is the reason birds have differently placed eyes?
Carnivorous bird eyes face forward
Non-carnivorous birds eyes face lateral
T/F some bird species can see ultraviolet
TRUE
What is unique about the nictitating membranes of avians?
Skeletal muscle so they can control them
What supplies nutrients and vascular supply to the inner eye in avians?
Pectin (similar to choroid in mammals)
Why do avians have decreased retinal blood supply?
To much blood flow interferes with vision
What is unique about avian photoreceptors?
Each receptor has a nerve attached
What is the fovea in birds? How many do they have?
Where everything focuses. Predator species have 2 so they can change what they focus on quickly
What is different in the auditory ossicles in birds?
They only have one bone called the columella
How do owls triangulate sound?
They have asymmetrical ear openings. One is above eye midpoint and one is below eye midpoint
Is the avian gustatory sense well developed?
No (bummer). Only have a few taste buds
What tactile senses do birds have?
Pain, heat, cold, touch
