3. Avian Anatomy and Physiology Pt 2 Flashcards
What is the bursa of fabricus?
the initial site of B lymphocyte production
What is different about the digestive system than other species?
birds have fast metabolism
high demand for energy is thus assimilated from food they consume
What is unique about the avian esophagus
crop = expansion over interclavicular space
a place for storage, lubrication and for passage of food
little digestion occurs
pigeons and doves: at breeding time, mucosal lining can break down to form “pigeon milk”
insect-eating birds: heavy epithelium protects from insect swallowed alive
What are the two separated compartments of the avian stomach
proventriculus = glandular stomach (chemical digestion begins here with pepsin and hydrochloric acid)
Gizzard = ventriculus = muscular stomach (striated muscles grind food, ingested grit aids in grinding food, undigested food ground into pellet by some species which is then regurgitated)
What does the liver and pancreas look like in avians?
Liver: bilobed, right lobe larger than left
Pancrease: Relatively large, especially in fish and grain eaters
rests in loop of duodenum
endocrine portion occupies more tissue mass than in animalsW
What is the duodenum’s main job for avian?
main organ for digestion and absorption of nutrients
varies in length and thickness depending on diet
What is the ceca’s job in the avian digestive system
paired sacs at junction of small and large intestines in some species
role in water reabsorption and in the bacterial fermentation of cellulose
contents excreted independent of fecal material
What is the large intestines role in the avian digestive system?
major role is reabsorption of water and minerals
What does the cloaca do? what is the 3 sections of it?
the end of the digestive tract
3 sections: coprodeum (receives excrement from intestine), urodeum (receives discharge from kidneys and genital ducts), protodeum (stores excitement and eliminates it)
Vent: muscular anus expels waste products = mute
What is mute?
combination of feces and urine
usually appears as a dark fecal center with white urates around it
varies by diet
can also be an indication of dz, therefore bird owners should monitor carefully - green mute = chlamydial infection, internal parasites or liver dz
What should we be careful about tube feeding birds?
direct feeding tube down esophagus making sure to avoid trachea; visualize back of throat as you feed to ensure there is no regurgitation
Is there anything different about the avian heart?
4 chambered, R side smler than left
lies in cranial portion of thoracoabdominal space
Which arteries are larger to meet the specialized demands of the avian bodies
Pectoral and brachial
Which blood vessels have been specialized to meet the demands of the avian body?
Renal portal system
What is the renal portal system in birds?
vry important when giving injections in leg
may pass thru portal system first and much of drug eliminated b4 it can affect body
also applies to lizards
What is different about blood flow in birds?
faster HR and more rapid blood flow bc of relatively fast metaolism
Where are electrodes placed on a bird for electrocardiograms?
Electrodes placed on wings and legs detect changes in electrical voltage as heart chambers contract and relax
What are the functions of avian blood
carry nutrients, O2, hormones to cells
Carry metabolic wastes to lungs and kidneys
control and prevent dz, regular body temp
What blood cells do birds have
Birds do not have platelets but they do have erythrocytes, leukocytes (heterophils, eosinophils, basophils, monocytes, lymphocytes and thrombocytes)
What do erythrocytes look like in avians?
oval, nucleated, and larger than those of mammals
formed in bone marrow of adult birds, or in spleen and liver depending on species
posses hemoglobin
total number of cells dependent on age, seg, diet and time of year
What are heterophils in bird cells?
phagocytes
equivalent to mammalian neutrophil
rought with rod-shaped red-orange granules
bilobed nucleus with clumped chromatin
What are thrombocytes in avian blood cells
nucleated cells that act as platelets
smaller than RBC’s with large, round-oval nucleus
Prod by bone marrow in adult birds
Why must the respiratory work quickly and effciently
bc of fast metabolism and high energy lvl
What does the avian oral cavity contain/
Several structures used in respiration, glottis, choana and larynx
What is unique about the avian trachea?
long - provides moisture to inhaled air, aids in production of sound
Coiled in some species
What is the syrinx
Voice box
enlargement of the trachea above the sternum
contains muscles, air sacs, vibrating membranes - vocalization complexity depends on the number of muscles present in the syrinx
What is unique about the avian bronchi?
Trachea bifurcates into 2 bronchi
Bronchi further divide into mesobronchi (in lungs), 2ndary bronchi = ventrobronchi, parabronchi, air capillaries - site of gas exchange w/ blood capillaries
What are unique about the avian lungs?
small, inelastic, highly vascularized - bright red, attached to thoracic vertebrae and ribs
What are the avian air sacs?
9 thin-walled, highly vascularized membranes, connect to the bronchi, some extend into the bone vacities
Func: air reservoirs, provide warmth and moisture to air, thermoregulation, provide buoyancy
How many inspirations and expirations are required to transport one pocket of air through the entire resp system?
2 inspirations and 2 expirations
T of F: Do birds have a diaphragm?
no
What are the key features of avian air flower?
Very efficient resp system - no mixing of inspired and expired air, arrangement of air sacs and capillaries further improves efficiency
Clinical applications - very rapid response and sensitivity to inhaled anesthetics
Birds are very sensitive to poisonous gases - canary in the coal mine, teflon pans
What are the typical avian RR?
rate varies with species, activity lvl, age, sex, time of day, and outdoor temp
Smler birds breathe faster than lgr birds
birds in flight have higher rate than nonflying birds
How do birds thermoregulate?
Birds have no sweat glands so heat is eliminated via respiration - water evaporated thru resp system helps cool overheated birds
can inc rate of cooling by panting or fluttering the upper throat patch with an open beak
What are some methods that birds can decrease their body temperatures?
bathing, dec activity, some species like vultures and storks will defecate on their own legs to inc evaporative cooling, adjust feather position
What are some methods birds can use to increase their body temperature
perching on one leg to minimize skin exposure
2. tucking head and beak under feathers on back, 3. shivering, 4. seeking sheltered roosts
5. Some species like hummingbirds can enter a temporary night-time torpor to conserve heat
6. Countercurrent heat exchange btw arteries and veins of legs
What demands of the avian body have blood vessels adapted to?
System of heat exchange in lower extremities thru network of arteries and veins placed close together
What is a salt gland?
Many marine birds and turtls have a special salt gland
they are located above each eye and drain into the nostrils
They secrete lg amounts of sodium chloride which helps maintain ideal osmotic conditions in the body while living and feeding in a high salt environment
What are some traits of the avian kidney?
kidneys are large and paired and 3 lobed, lie flush with backbone, has no renal pelvis,
contains 2 types of nephrons;
Looped: similar to mammalian nephrons
Unlooped: similar to reptilian nephrons
Renal portal system allows blood from the hind legs to be filtered thru kidneys or drain directly into vena cava - controlled by a valve
Birds do not have a urinary bladder
How does urine composition of birds differ from mammals?
higher conc of uric acid, eliminated as a white past in combo w/ fecal material, fecal material normally green or brown with a ring of white (uric acid)
Why is its beneficial for birds to eliminate their urine with their fecal matter?
Advantageous bc more efficient way to get rid of nitrogenous waste bc of less water loss, allows embryo to store lg amounts of nitrogenous waste within confines of shell - wouldn’t be possible if eliminating thru urea bc volume is too high
urea is toxic, but uric acid is not
Which one is toxic? Uric acid, or urea
Urea
What effects on the reproductive system might have when its time for breeding season?
breeding season often stimmed by inc day lengths in parts of the world where seasons are pronounced
affects hypothalamus and causes inc secretion of gonadotrophic hormones
in non-breeding animals have very sm gonads, which increase in size as breeding season approaches
Telling what sex it is is hard if its not breeding season, but DNA testing is available
What do avian testis look like? What temperature is ideal for them? What does the vas deferens carry?
Testes are bean shaped and located internally, but sperm are stored in a pouch called a seminal vesicle
Temp here is about 4C COOLER than body temp for better sperm survival
Vas deferens carries sperm to seminal vesicle and cloaca
How do birds copulate?
behaviour stimmed by androgens (from leydig or interstitial cells in testes)
some species (galliforms, ratites, and ducks) have a grooved penis that assists in sperm transfer
Others simply bring cloaca together
What is unique about the female avian reproductive tract?
left ovary and oviduct are developed, but right side is non-functional and undeveloped
basic ovarian follicle development and ovulation similar to mammals
Ova discharged from ovary, picked up by infundibulum and passed thru oviduct. As egg passes thru oviduct and uterus, surrounded by layers of albumin (egg white) the shell membrane, shell and pigments. egg then passed thru cloaca
What are the 5 sections of the avian oviduct?
Each contributes to egg development
1. Infundibulum: catches ovum and is fertilized
2. Magnum: secrete albumin
3. Isthmus: secretes inner/outer shell membranes
4. Uterus (shell gland): secretes watery albumin, the shell, and pigmentation
5. Vagina: secretes mucus for egg laying and stores sperm for hours to days
What is egg binding or egg bound?
A fully formed egg fails to pass from uterus to cloaca
during egg laying the intestinal exit is blocked so affected birds often stop passing feces
become depressed, off feed, penguin like gai
medical emergency!! tx w/ anti-inflams (preparation H, baths, calcium supplements and manipulation; sometimes may have to collapse egg
How can we prevent egg binding?
avoid obesity, watch out for vent pecking and separate affected birds, make sure adequate calcium in diet
What is a clutch
of eggs laid and incubated
How many eggs will a clutch have, what are determinate layers, indeterminate layers?
Number varies among species, from 1-20
Total may be determinate layers: predetermined by # of follicles developing on ovary
Indeterminate layers(most birds): eggs are continuously prod until a set 3 reached in nest - in these species signal to stop includes visual, tactile, hormonal influences indicating a full clutch. Endangered species: remove initial eggs and rear artificially
How many times may eggs be laid, when are they incubated?
May be laid every day, other day or 4-5 day intervals
some species begin incubating at once, resulting in chicks hatching at varying times
other species only begin incubation once all egs are laid - results in synchronous development of chicks, hatch at same time
How are eggs incubated?
eggs need to be kept warm and humid
female develops brood patch (featherless patch of sin on belly where skin folds, thickening, and blood circulation create heat pad for eggs
time for incubation varies among species but longer for lgr birds
18 days for budgies
How do birds hatch?
requires a specialized egg tooth on the bill and hypertrophied neck muscles or hatching muscle
What are the 4 ways to classify chicks?
depends on feather cover, open or closed eyes, and mobility
What are the 4 classificaitions of chicks?
- Precocial: ducks/geese - downy feather, open eyes, mobile
- Semiprecocial: gulls and terns - downy feahter, open eyes, may be mobile, remain in nest and dependant on parents
- Semialtricial: hawks and owls - downy feathers, open (hawks) or closed eyes (owls), not mobile
- Altricial: songbirds - little to no feathers, closed eyes, not mobile
