Reptiles Flashcards
What is the cause of most reptile diseases in the UK?
Poor nutrition and husbandry e.g. Think lizard with calcium problems in bones
What does stress do?
Reduces immune response and predisposes to infection
Describe the taxonomy of reptiles.
Kingdom? Phylum? Class? And various orders?
Animalia
Chordata
Reptilia
Chelonia, Squamata, crocodilia, rhynocephalia
What do you need to keep crocodilia spp as pets
A dangerous/wild animal licence
What is the only reptile belonging to the group rhynocephalia
Tuatara
These are endemic of nz. They have a pronounced third eye involved in circadian and seasonal cycles
Which is the largest order?
What animals are in this order?
Squamata
Snakes. Lizards and worm lizards
Reptiles are ectothermic (rely on external sources of heat). They have a slower metabolism. They utilise mainly aerobic respiration but can switch to anaerobic if extra energy is needed. What’s the consequence of this?
Build up of lactate. Little ok as dealt with by buffering system but too much leads to lactic acidosis
What 4 things does metabolism depend on?
Diet and feeding behaviour
Size
Body temperature
Species
Describe thermoregulation in reptiles
Thermoregulation is controlled by the hypothalamus, specifically the pre optic nucleus.
Blood passes from the heart to the hypothalamus via the internal carotids.
Appropriate behavioural mechanisms can then be undertaken.
Heliothermy= direct solar radiation
Thigmothermy= contact with warm object
What other things are altered for thermoregulation?
Heart rate
Vasodilation/constriction
Lungs bypassed by shunt to reduce heat loss by evaporation
Behavioural means- position, shape, burrowing, pigmentation
What are UVA and UVB important for?
A- stimulates reproductive behaviour in lizards
B- important for calcium metabolism
What factors triggers hibernation?
Temp Size/weight Photoperiod Reproductive cycle Food availability
Why is hibernation important?
Triggering reproduction activity
Maintaining normal thyroid activity
Describe the process of hibernation?
Withhold food for 2 weeks before to ensure nothing in gut that will ferment, reduce temperature, check and weigh regularly. Hibernate from November through to march. When waking up, bathe in water water to encourage drinking and expulsion of faeces.
Give some facts about the skeletal system of reptiles
Not Haversian canal system
Bone healing slow
When dealing with fractures must correct nutritional deficiencies
Chelonions and snakes have modifications to their axial and appendicular skeletons
Chelonions, snakes and crocodiles never stop growing- growth plates never shut
Lizards growth plates do shut, but later on
What happens when plasma ca levels are unsufficient to support neuromuscular activity?
PTH mobilises calcium from the bones
This is why you see lizards with metabolic bone disease
On X-rays bones appear clear rather than white
Name the three skull types, how do they differ? What species have each?
Anapsid = no temporal fenestrate = Chelonia
Synapsid = 1 subtemporal fenestrae
Diapsid= supra and subtemporal fenestrae= snakes, lizards, crocs, tuatara
How would you describe a snakes skull?
Kinetic
Has moveable joints between upper and lower jaw
What does ecdysis mean?
Skin shedding
Name the layers of the skin compared to normal
3 layers opposed to 5: stratum corneum, intermediate layer, stratum germinativum, stratum basale
5: cats love gravy so bad= corneum, lucidium, granulosum, spinosum, stratum basale
What controls ecdysis?
The thyroid
What does dysecdysis mean?
What is the usual cause?
Name 2 things ecdysis requires
Failure to shed
Husbandry
Humidity and shedding surface
What tube would you use to take reptiles blood?
When doing a smear, you’d use edta- why would you not use this with reptikes?
Lithium heparin
EDTA can lyse RBCs
How many chambers are there in the reptile heart?
Except which? Which is this similar to?
3
Crocodiles have 4= same as mammals and birds
There are 2 Atria and 1 ventricle, but the ventricle is split into 3 by muscular ridges, name the parts
Cavae arteriosum, pulmonae and venosum
Think veins, arteries and lungs
What two things keep mixing of oxygenated and deoxygenated blood in this ventricle to a minimum?
Timing of contractions
Division of chambers
What happens when reptiles breath hold?
Pressure in lungs increases
Therefore blood bypasses the lungs and passes into aortic arch
This has implications during anaesthetics