Reptile anatomy Flashcards
Give a definition of exothermic?
Regulate temperature by behavioural means, can function at different external temperatures
Compare the preferred optimum temperature zone and the preferred body temperature
POTZ = range which allows the reptile to achieve its preferred body temperature PBT = optimum temperature for the correct functioning of all body systems
What will a sick reptile seek out?
High temperature - behavioural fever
What are the two main mechanisms for acquiring heat?
Heliothermy - radiation from the sun
Thigmothermy - conduction from a warm surface
How does the CV system react to cold temperatures?
Heart rate and vasodilation decrease - warm blood retained in core
Lungs can be bypassed by means of a shunt, meaning reduced heat lost to evaporation
How does reptile pigmentation affect thermoregulation?
Can increase melanin in the skin to increase heat absorption
Do reptiles have faster or slower metabolisms to animals of a similar size? What is the rate dependant on?
Slower
- diet
- size
- body temp
- species
What are the consequences of reptiles switching from aerobic to anaerobic metabolism?
Lactic acid produced reduced the blood pH, meaning they have a lower affinity for oxygen so require a recovery period
Where is 99% of the reptiles body calcium stored?
In bones
What are the two skull types seen in reptiles?
- Diapsid: 2 fenestrations behind eyes (snakes, lizards)
- Anapsid: no fenestrations behind eyes (chelonian)
What are the 3 integument layers in reptilia?
- Stratum corneum
- Intermediate layer
- Stratum germinativum
What controls ecdysis?
Thyroid gland
What is Dysecdysis?
Failure to shed, usually husbandry related
How are reptilian RBCs different to mammals?
They are nucleated
Describe the reptilian heart
Three chambers - 2 atria and one ventricle
Name the 3 muscular ridges the reptile ventricle is subdivided into
Cavae arteriosum
Cavae pulmonale
Cave venosum
How is mixing of oxygenated and deoxygenated blood kept to a minimum in reptile hearts?
Timing of contractions
Division of chambers
What are the 2 reptilian CV portal systems?
- Renal portal system: external iliac veins enter a large renal portal vein meaning some blood returning from hindlimbs enters the kidney before being returned to circulation
- Hepatic portal system
How can the lungs differ in snakes?
Left lung can be vestigial or absent
As reptiles don’t have a diaphragm how do they breathe?
Breathe using negative pressure which is created by the intercostal muscles
The lungs have a role in respiration in a reptile, but what else?
Buoyancy
Vocalisation
Display
What is the controlling factor of respiration?
Temperature - increases oxygen demand and reduced pulmonary resistance
Which reptilian species have teeth?
Lizards and snakes
What 4 factors is the rate of digestion in reptiles affected by?
- Type of food
- Energy demand
- Temperature
- Disease/illness
