More reptile anatomy and physiology Flashcards
What are the 2 Chelonian sub-orders? What is the main comparison between them?
- Pleurodira: can flex neck at 3 points (S-shape horizontally)
- Cryptodira: can flex neck at 2 points (S-shape vertically)
How do chelonia gain heat?
Heliothermic - by basking in the sun
What is the shell composed of?
Keratinised plates called scutes.
Scutes overlie dermal bone plates
What are the names given to the dorsal dome part and ventral flattened parts of the shell?
Dorsal = carapace Ventral = Plastron
How is the skeleton of chelonia modified?
- limbs project laterally
- spine and ribs fused
- pectoral and pelvic girdle vertical within the ribcage
Describe the respiratory system of chelonia
- Nasal breathers
- Trachea short
- No diaphragm
- lungs lie dorsally and under carapace
- can switch to anaerobic respiration
Where does the heart lie in chelonia?
Posterior to the pelvic girdle
How many chambers does a chelonia heart have?
3 - 2 atria and one ventricle
Where in chelonia would you take a blood sample?
Jugular vein
Dorsal coccygeal vein - in tail
How do chelonia grasp and chew food?
No teeth so use sharp beak instead
Thick fleshy tongue
What are the 2 methods of urine excretion in chelonia
- directly into urodeum
- refluxed into bladder or colon for further water conservation
How can a male chelonia be identified from a female?
- Concave plastron to assist with mounting
- Presence of phallus
- Longer distance from caudal edge of plastron to cloaca
- Longer, broader tails than females
Give a definition of oviparous
Females produce young by means of eggs which are hatched after they have been laid by the parent
What are the 3 thermoregulation methods of lizards?
- Colour change: melanin pigment
- Body posture/position
- Behaviour
In lizards which muscle is responsible as the main jaw opener?
Depressor mandible
In lizards which 2 muscles are the main jaw closers?
Pterygoideus
External adductor muscle
What are the 2 specialised functions of the tail in liazrds?
- Site for fat storage
- Can be shed as a defence mechanism
How does the GI tract differ for lizards that are omnivorous/insectivores compared to Herbivores
Omni/Insect = short and simple Herb = hindgut fermenters
How are herbivore lizards adapated to deal with high potassium diets?
Have salt glands which are an additional route for excretion
How can male lizards be sexed?
- larger and more colourful
- presence of prominent dewlaps, crests and spines
- prominent femoral pores on the thigh area
- cloacal bulge
What is the ideal temperature range for snakes?
18-34 degrees
What anatomy is found in the cranial, middle and caudal regions of a snake?
Cranial - heart, trachea, oesophagus, thyroid, proximal lung
Middle - stomach , liver, lung, spleen, pancreas
Caudal - intestines, kidneys, gonads (cranial to kidneys)
What allows a snake to continue breathing as they swallow?
Glottis is rostral, avoids occlusion whilst swallowing
What does a snake use its tongue for?
Olfaction, taste, touch
Which muscles provide assistance for food moving through the body?
Axial muscles - trunk and head
How can male snakes be sexed?
- Tail base broader
- Eversion of hemipenes
- Probing cloaca
Which is a snakes most well developed sense and why?
Olfaction - Jacobson’s organ in addition to normal olfactory cells
What is the importance of Thermoreception in snakes?
- Infra red sensors in-between eye and nostril
- Allow detection of warm blooded prey in complete darkness
