Unit 4 - Reptile A&P And Clinical Techniques Flashcards
Where are tuataras only found?
on islands off coast of new zealand
What are the 4 orders of class reptilia
1 crocodylia (alligators and crocs
2. squamata (snakes and lizards
3. chelonian (turtles and turtoises)
4. rhyncocephalia (tuataras)
What are the 3 orders of class amphibian?
- gymnophiona (caecilians) worm/snake like amphibian
- Anura (frogs and toads)
- Caudata (salamanders and newts
What is unique about reptiles and amphibians metabolism
they are ectothermic or cold blooded
ectothermic animals are unable to generate lg amounts of body heat internally - body temp depends on enviro temp
some lg reptiles can markedly raise body temp by muscular contractions
Ex. leatherback sea turtle swimming, pyhons (shiver when incubating egs)
How do reptiles and amphibians thermoregulate?
herptiles - mainyl regulate body temp via behaviour
sun bathing, changing skin color, coiling or uncoiling
less important if in hot enviro
What is ectothermy?
related to energy conservation
animal metabolism depends on body temp
allows many herptiles to survive on very small amount of food
depends on access to temps within the preferred optimal temp zone (POTS)
What is POTZ?
range of temperature in which the animal can perform all necessary metabolic functions
critical that an ill patient’s environment is at POTS as well as when administering meds
if not, can lead to a no response to treatment, lack of healing, overdose or even death
Preferred optimal temperature zone
What do we need to keep in mind about reptile integument
limited subcutaneous space so it is difficult to administer subq injections
What is unique about the dermis of reptiles?
dense connective tissue
blood and lympth vessels, nerves and chromatophores (Pigment-containing cells)
chromatophores allow some lizards to change skin color and pattern
osteoderms; bony plates within dermis of some lizards and crocodilians
What is uniqe about the epidermis of reptiles?
scales and scutes of reptiles are formed by epidermal folds in most reptiles. vary in size and shape.
epidermis is keratinized
What are some other epidermal structures that could be present on a reptile?
crests, tubercles, spines and dewlaps, keels, horns and barbles
How is an epidermal plate numbered?
Starting from the head/cervical scute, the outside ring is the marginals. 2nd ring is the pleural scutes and the big scutes along the back is the vertebral scutes.
What is ecdysis?
shedding of skin
occurs w/ growth and in response to skin injury
shed in pieces or in one large piece
shed skin: exuvia
controlled by the thyroid gland
cells replicate new epidermis
enzyme containing lymph secreted btw old and new epidermal layers
skin colors dulls; spectacle opacifies
lymph - resorbed prior to ecdysis
mechanical rubbing on objects aids shedding
What does dysecdysis mean?
abnormal shedding
usually rom poor husbandry - low humidity, no objects in enviro to rub against, malnutrition and dehydration
can also be due to skin wounds, illness, dermatitis and parasites
fix by correcting problem and a 2 hour warm water bath
if not corrected can lead to dyspnea, dermatitis, future shed issues and loss of toes or tail tips
What is unique about the amphibian integumen?
extremely permeable - absorbs water directly from enviro, has drink patches or areas of inc permeability on ventral surfaces
epidermis - single or few layers of keratinized cells - aquatic amphibians - no keratinized cells
Dermis - chromatophores and glands that prod secretions which help protect the amphibian’s skin
Toxic secretions - prod by some glands within dermis and epidermis as defense mechanisms
Dermis - little subq space in salamanders and caecilians (anurans: looser attachments of dermis(more Sq space)
amphibians regularly shed outer layers of epidermis and usually eat the exuvia
How might we monitor a reptiles nervous system under anesthetic?
tongue withdrawal, jaw, pedal and tail reflexes are all present
When monitoring depth of anesthesia in reptiles other than snakes, can use corneal and palpebral reflexes
In snakes, tongue withdrawal reflex will be maintained at the surgical plane of anesthesia
What is unique about reptile vision?
iris made up of skeletal muscle under voluntary control - Pupilary light reflex not seen, lower lid usually more mobile than upper
Some species of lizards have thin, transparent lower lids to allow for a degree of vision even when lids are closed
nictitans: well developed, mobile in many reptiles
Which reptiles don’t have a true eyelid? What do they have instead?
snakes, some lizards
clear, fused scale or spectacle
caecilians eyes - covered w/ skin
How is the vision of reptiles?
poorly developed extraocular muscles
except chameleons; eyes move freely and independently of one another
What is the tear film
btw cornea and spectacle in sub-spectacular space where tears drain into mouth thru nasolacrimal duct system
Does chelonians have nasolacrimal ducts?
no, tears spill over lid margins
What is unique about amphibian eyes compared to the rest
often protrube ventrally into oral cavity when animal swallowing
What are ossicles? What about the lens? How do they accomodate
scleral bone spresent in most reptiles - except snakes and crocodilians
lens: more fluid in reptiles than mammals (more rigid in snakes)
Chelonians - lens is squeezed thru the pupil
Snakes - lens moves back and forth due to pressure changes within the aqueous and vitreous humors
parietal (rudimentary) eye in some reptiles
What is hypovitaminosis A?
common dz for turtle/tortoises
usually from deficient diet
treated w/ vit A (injectable or dietary supplements) - also need to treat and 2nd bact infections
What are some possible signs of hypovitaminosis A?
swollen eyelids, loss of appetite and weight, raw skin w/ 2nd bact infections, nasal discharge (runny nose)
abnormal development of the eyes in embryos
How do snakes hear?
Columella articulates w/ quadrate bone
allows snakes to be very sensitive to ground vibrations transmitted thru the mandibles
snakes also able to hear aerial sounds
What are aural abscesses in reptiles?
middle ear infections common in chelonians
can be 2nd to hypovitaminosis A
Where does the location of hear lie for chelonians, most lizards, crocs and some lizards, and snakes
Chelonians - on midline just caudal to thoracic girdle, ventral to lungs
Most lizards - within thoracic girdle
Crocodilians and some lizards - farther back into the coelomic cavity
snakes - usually @ junction of the first and 2nd 3rd of the body length - fairly mobile within coelomic cavity
What is different about reptiles and amphibians hearts than mammals?
3-chambered heart w/ two atria and one ventricle
crocodilians have 4 chambered heart, but not like the mammalian or avian heart
no mixing of oxygenated and deoxygenated blood
How do we get a HR with reptiles?
difficult to auscultate. May be able to see movement thru skin
rate depends on species, size, temp, activity lvl and metabolic fun
Lizards - vasovagal reflex induces drop in HR, BP and catatonic state - triggered by applying gentle pressure to both eyeballs tru closed lids
lizard recovered w/ cessation of pressure or mild stimulation
How do reptiles breath?
reptiles can survive living long periods w/o breathing
resp driven by O lvls in blood
lizards tend to experience severe resp depression while under anesthetics, so important to admin positive pressure entilation (two to four respo per minutes)
What should we know about the glottis of reptiles and amphibians?
most amphbs and reptiles - rostral portion of oral cavity
glottis very mobile in snakes; protrudes from mouth to allow respiration during ingestion of prey
Paired arytenoid cartilages: border glottal opening; open turning respiration
The visible glottis makes it easy to pass ET tube and to avoid trachea when passing a stomach tube for force feeding
What is a glottal keel?
present in some snakes - increase volume of vocalizations and makes intubation difficult
Can reptiles and amphibians makes vocalizations?
only possible are hissing, grunting, bellowing
frogs and toads - vocal sacs arise from trachea
no vocal cords
How do reptiles breath?
no true diaphragms
action of intercostal muscles and parts of axial musculature used for respiration
do not restrain too tightly
How do amphibians breath?
simple saclike lungs
some salamanders have no lungs - cutaneous respiration
Pulmonary ventilation results from pumping of buccal cavity and pharynx - gas exchange can also occur across MM of buccal cavity, pharynx and cloaca
Gills may also be present, particularly in young amphibians
Are reptiles, snakes, crocodiles and adult amphibs carnivorous, omnivorous or herbivorous
reptiles can be carnivorous, omni or herb
snakes/crocos/adult amphibs strict carnivores
some diets are very specialized
What is the oral cavity of snakes and lizards like?
deeply forked tongues
function as particle delivery system for vomeronasal organ
allow for detection of particle gradients
What does the oral cavity of chameleons, turtles and tortoises like?
Chameleons: specialized projectile tongues designed for capturing prey from a long distance - sticky end to stick prey w/
turtles/tortoises - typically thick, fleshy, relatively immobile tongues
What does the crododilian oral cavity look like?
imobile tongue attached to intermadibular space
muscular flaps from base of tongue and dorsal pharynx allow for opening of mouth while submerged without ingesting or inhaling water
Which reptiles has venom glands?
some snakes, lizards - modified salivary gland
What is the dentition like of turtle and tortoises?
no teeth, tomia (keratinized beaks), other reptiles - teeth
What is the dentition of snakes like?
snakes have 6 rows of teeth, two mandiblar, two max and two on palatine/pterygoid bones
snakes w/o venomous fangs called aglyphous snakes
What are snakes w/o venemous fangs called?
aglyphous snakes
What is the dentition like of amphibs?
most have teeth
caecilians and salamanders - both max and mand teeth, palatal teeth in some
max dentition present in some anuran species
odontoid process - cutting plates on rostral mand of some frogs
What is the esophagus of reptiles?
thin and distensible - usually reflects type of prey
amphib eso very short and wide, especially in anurans
What does the stomach of reptiles look like?
variable size and shape
snakes - highly distensible
crocs - thick muscle compared to avian gizzard
What does the stomach of amphibian’s look like?
capable of prolapsing stomach thru mouth
used for emptying stomach if they ingest something undesirable
gastric prolapse is terminal in dying animals
can be seen with some methods of anesthesia
Can reptiles and amphibians have foreign bodies
100%
Which has a longer intestinal tract? herbs vs carni’s?
Herbirvores
Snakes have relatively straight int tract
Where does hindgut fermentation for digstion occur in reptiles?
in the colon, large and complex in herbivores
Where does the site of hindgut fermentation in herbivorous lizards and chelonians occur?
cecae
How does the liver in reptiles look like?
large and bi-lobed
What is the cloaca?
outflow of GI and urogenital tract
three chambers - coprodeum, urodeum and proctodeum
What do we need to avoid when injecting into the caudal half of reptiles?
the renal portal system arising from veins of pelvic limbs and tail
What is unique about amphibian kidney?
excrete ammonia as a nitrogenous waste product; others excrete urea, some excrete uric acid
no ability to concentrate urine
urinary bladders and cloacal anatomy similar to reptiles
What does the male reptile repro system look like?
males have internal testes loc in dorsal coelomic cavity
ductus deferens leads from testes to dorsal wall of the urodeum
they possess a copulatory organ such as phallus or paired hemipenes
Most also have a sexual portion to the renal tubules - develops in response to high lvls of circulating sex hormones and provides secretions that contribute to the seminal fluid
What are the copulatory organs of croc’s and chelonians?
Phallus of erectile tissue rising from floor of cloaca
What are the copulatory organs of snakes and lizards?
paired hemipenes everted from the tail base thru the vent
What does the female repro system look like?
paired ovaries in dorsal coelomic cavity
paired oviducts lead to cloaca and end at genital papilae in dorsal wall of the urodeum
What is the reptile repro cycle?
In viviparous species, fetuses are retained
and nourished in uterine portion of oviduct
Oviposition - many reptiles dig nests to lay
eggs
◦Without suitable nesting material, female
may experience dystocia
Chelonians and lizard species may excavate
deep holes to deposit eggs
What happens after oviposition or parturition, reptiles not involved with care of eggs or offspring
Exceptions - crocodilians protect their nests and
young for a period of time following hatching
◦ Pythons and cobras - protect their nests until
hatching
What is egg incubation
Development and hatching requires proper temperature, humidity,
and gas composition of nest
Incubation time and temperature varies
Reptile eggs should not be rotated during incubation
How is sex determined?
Determined by genotype or temperature at
which eggs are incubated
Sex chromosomes:
◦Females are heterozygous (ZW) and males
are homozygous (ZZ)
How is sex determined in reptiles?
Some species do not have sex
chromosomes
◦ Higher incubation temperatures produce males
in crocodilians and lizards
◦ Opposite occurs in chelonians
◦ Temperature range within the nest allows for
production of a mixed clutch of hatchlings
What are secondary sex characteristics of snakes
Snakes - no real sexual dimorphism
In some species, pelvic spurs can be larger in males
◦ Pelvic spurs: remnants of pelvic limbs; provide tactile stimulation to
female
What are some secondary sex characteristics of chelonians and lizards?
Male chelonians may have concave plastron and more distally located
vent
◦ Allows closer apposition of the cloacas when the male mounts the female
Some lizards show obvious dimorphism
◦ Example: the male Jackson’s chameleon has three well-developed horns
on its face
How is sexual dimorphism in amphib repro?
Sexual dimorphism in some species
◦ Poison dart frog males have enlarged toe pads
◦ Large tympanic membranes in some male anurans
◦ Prominent cloacal glands in male salamanders
What does amphib repro look like?
Paired gonads in dorsocaudal coelomic cavity
Most caecilians (serpentine amphibians) are viviparous
Most anurans and salamanders are oviparous
amplexus
spermatophores
What is amplexus?
Amplexus - Male frogs and toads fertilize eggs as they are laid while
grasping the female
What are spermatophores?
Spermatophores - packets of sperm deposited onto substrate by male
salamanders
◦ Picked up by the female salamander’s cloaca
◦ Spermatotheca - pocket in cloaca of female salamanders where sperm can
be stored
Once eggs are born, what is their life cycle?
eggs usually deposited in or near water
some parental care of eggs and/or young in anurans and most salamanders
larval anurans (tadpoles) have completely aquatic lives prior to metamorphosis
tadpole metamorphosis - usually complete within 90 days - stimulated by thyroid hormones
What is unique about snake skulls?
extremely mobile
Mandibular symphysis
is connected by
ligaments that allow
jaws to move
independently of each
other
What is tail autonomy?
defensive mechanism - some lizards and salamanders. discarded tail usually continues to wiggle and distract predator
species capable of tail autonomy have fracture planes along which tail breaks that have little to no blood loss
lost tail can regenerate,regenerative tail still and cartilaginous
What is metabolic bone disease in reptiles and amphibs
Caused by an imbalance of calcium, phosphorous and Vitamin D3
Proper diet, temperature and lighting will prevent MBD
Symptoms include swollen mandible, curvature of the tail and possibly the spine and decreased bone density on radiographs.
How do we control snakes?
control the head
Grasp just behind the head, then support the rest of the body with
your other hand/arm; or allow body to rest on the same arm so one
hand is free
Must support at least 2 points
How do we control lizards?
depends on the type of lizard
Support the body and give something for feet to rest on
Iguanas – very large tails that can thrash (wear long sleeves); may bite; very fast
Geckos – may lose their tail if handled roughly (avoid handling tail if possible)
Always warn owners of this possibility prior to handling/blood collection
How do we restrain chelonians?
support the shell
May bite
Can use a block in front of face to keep their heads retracted into shell
(ie. Tongue depressor)
What are ways to take blood from a snake?
cardiocentesis (only is anesthitized)
tail vein
How are blood collected from a lizrds?
tail vein
How is blood collected in a chelonians?
jug + subcarapacial sinus
How do we take rads with reptiles?
Goal is similar views as for mammals for most reptiles
At least one lateral and a VD/DV
Often easier said than done
Sometimes, you have to get creative
Very helpful to have a mobile X-ray tube
Can use dental x-ray for very small reptiles (tiny lizards, pediatrics,
etc.)
Often, anesthesia (or at very least sedation) may be required
How do we take rads of snakes?
Can manually hold the section you want to X-ray
“Snake in a box” can give a nice whole-body DV view
