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
