Lecture 23/24: Reptilian GI Physiology (Wellehan) Flashcards
monophyletic group
group that contains all descendents from a common ancestor
squamate
lizards + snakes
first group to branch off from squamates
geckos
main radiant heat source
the sun
do most reptiles use radiant or contact heat sources in the wild?
radiant. It is difficult to maintain an even gradient with a contact heat source
space heaters and aquarium heaters provide contact, radiant, or convective heat?
convective
postprandial means:
after a meal
How is postprandial metabolic rate affected by temperature?
Higher temp = faster metabolic rate
Why are acrodont type teeth clinically relevant?
They are prone to periodontal disease and sloughing of the dental cascade. These type of teeth don’t continuously replace themselves
-common in chameleons
lead poisoning in gators can lead to:
loss of teeth
To do dental work on a gator, which nerve should be blocked?
mandibular
Herpesviruses are common in which reptiles?
tortoises and lizards
Where do herpesviruses reside histologically?
within host cell nuclei
What other clinical signs are assoc. with lizard herpesvirus?
stomatitis and hepatitis
Explain why cardio physiology is very important for GI in crocodiles *
Crocodiles have a complete vetricular septum unlike other reptiles. The right aortic arch is the main outflow of the heart, however the left aortic arch persists and carries less oxygenated blood. This blood with a higher CO2 can be carried to the stomach where it helps create a very low pH in the stomach. ligation of left aorta causes a decrease in gastric acid production
Which animals have a complete ventricular septum?
mammals, birds, crocodiles.
Foramen of Panizza
aperture b/w R and L aortic arches. Shrinks with adrenaline
Subpulmonary conus
cog-tooth valve that blocks pulmonary outlfow. Opened by adrenaline
In crocodiles, the right ventricle feeds which major arteries?
pulmonary and left aorta
pathway of respiratory system in birds
trachea –> bronchi –> bronchioles –> lungs –> air capillaries –> air sacs
increased bicarbonate –> O2 bound to hemoglobin
decreases. (causes O2 release)
gastric acid secretion –> chloride, bicarbonate
depletes chloride, increases bicarb.
clades of cryptosporidium are related by:
their trophic form (what part of the GI they infect)
clinical signs of cryptosporidium
wasting, gastritis, enteritis, aural polyps. May be asymptomatic
methods for diagnosing crypto
- acid fast staining
- stomach washes
- enzyme immunoassay
- PCR (easiest method)
- GI biopsy
What are spirurids?
an order of nematodes, often found in gastric mucosa
adenoviruses
diverse, stable, non-enveloped viruses found in reptiles. Usually host-specific. Commonly seen in co-infections. clinical signs = enteritis, hepatitis, etc.
siadenovirus (a type of adenovirus) is found in which species
tortoises. >80% mortality rate! Never subclinical
poster child for adenovirus
bearded dragons
Methods of diagnosis for adenovirus
- electron microscopy
- in situ hybridization
- PCR
treatment for adenovirus
cidofovir in mammals. No known treatment for reptiles
Gastric neuroendocrine carcinoma
a somatostatin producing tumor found commonly in bearded dragons. Causes hyperglycemia
How are bearded dragons and horses similar with respect to GI?
both are hind gut fermenters
eat a meal –> growth and diversity of gut flora
increases. EXCEPT for bacteroidetes, which decreases after eating.
eat a meal –> heart ventricular size, size of intestinal villi in pythons
both increase
entamoeba invadens
pathogenic protozoal parasite of reptiles, causing colitis and gastritis. Tx = raise temperature (they are temp. sensitive)
parabasalidea
- commonly found in normal animals
- assoc. with flagellates
- causes colitis
- tx = metronidazole
types of coccidia
intestinal, extraintestinal, intranuclear.
methods of diagnosing coccidia
- intestinal: fecal flotation
- extraintestinal: histology
- PCR
most effective tx for coccidia?
toltrazuril
reovirus
- stable, unenveloped, rapidly reproducing segmented virus
- easily reassorts; hard to vaccinate against
- causes lipid depletion
Do nematodes have direct or indirect lifecycle?
direct
Do acanthocephala (thorny headed worms) have direct or indirect lifecycle?
indirect
3 parts of cloaca
coprodeum, urodeum, proctodeum
where is calcium first lost when a reptile makes an egg?
phalanges
most common health problem in reptiles
obesity
nutritionally simplest reptiles
snakes. All are carnivores, typically eat whole prey.
T or F: venom may be necessary for digestion
T
Why is it better to feed pre-killed prey to snakes?
no risk of injury, can be stored frozen. However, in feeding frozen fish there is a concern about thiaminase
when do snakes typically eat their first meal?
After their first shed
Common health problems in captive lizards
- dehydration
- obesity
- underfeeding
- incorrect Ca:P ratio in food
- Vit. D toxicity
what causes tongue incoordination in chameleons?
Ca deficiency
piscivorous means:
eats fish
what are chelonians?
turtles and tortoises
prolapses in chelonians are often assoc. with
vitamin A deficiency
common health problems in captive chelonians
- secondary hyperparathyroidism to nutritional problem
- vit. A deficiency
- thiamine deficiency
lizards require sunlight for:
vitamin D metabolism
herbivorous chelonians are prone to:
nutritional secondary hyperparathyroidism, fiber deficiency, calcium deficiency
