Reptile anatomy

Question 1

Give a definition of exothermic?

Answer 1

Regulate temperature by behavioural means, can function at different external temperatures

Question 2

Compare the preferred optimum temperature zone and the preferred body temperature

Answer 2

POTZ = range which allows the reptile to achieve its preferred body temperature
PBT = optimum temperature for the correct functioning of all body systems

Question 3

What will a sick reptile seek out?

Answer 3

High temperature - behavioural fever

Question 4

What are the two main mechanisms for acquiring heat?

Answer 4

Heliothermy - radiation from the sun

Thigmothermy - conduction from a warm surface

Question 5

How does the CV system react to cold temperatures?

Answer 5

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

Question 6

How does reptile pigmentation affect thermoregulation?

Answer 6

Can increase melanin in the skin to increase heat absorption

Question 7

Do reptiles have faster or slower metabolisms to animals of a similar size? What is the rate dependant on?

Answer 7

Slower

• diet
• size
• body temp
• species

Question 8

What are the consequences of reptiles switching from aerobic to anaerobic metabolism?

Answer 8

Lactic acid produced reduced the blood pH, meaning they have a lower affinity for oxygen so require a recovery period

Question 9

Where is 99% of the reptiles body calcium stored?

Answer 9

In bones

Question 10

What are the two skull types seen in reptiles?

Answer 10

• Diapsid: 2 fenestrations behind eyes (snakes, lizards)

- Anapsid: no fenestrations behind eyes (chelonian)

Question 11

What are the 3 integument layers in reptilia?

Answer 11

• Stratum corneum
• Intermediate layer
• Stratum germinativum

Question 12

What controls ecdysis?

Answer 12

Thyroid gland

Question 13

What is Dysecdysis?

Answer 13

Failure to shed, usually husbandry related

Question 14

How are reptilian RBCs different to mammals?

Answer 14

They are nucleated

Question 15

Describe the reptilian heart

Answer 15

Three chambers - 2 atria and one ventricle

Question 16

Name the 3 muscular ridges the reptile ventricle is subdivided into

Answer 16

Cavae arteriosum
Cavae pulmonale
Cave venosum

Question 17

How is mixing of oxygenated and deoxygenated blood kept to a minimum in reptile hearts?

Answer 17

Timing of contractions

Division of chambers

Question 18

What are the 2 reptilian CV portal systems?

Answer 18

• 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

Question 19

How can the lungs differ in snakes?

Answer 19

Left lung can be vestigial or absent

Question 20

As reptiles don’t have a diaphragm how do they breathe?

Answer 20

Breathe using negative pressure which is created by the intercostal muscles

Question 21

The lungs have a role in respiration in a reptile, but what else?

Answer 21

Buoyancy
Vocalisation
Display

Question 22

What is the controlling factor of respiration?

Answer 22

Temperature - increases oxygen demand and reduced pulmonary resistance

Question 23

Which reptilian species have teeth?

Answer 23

Lizards and snakes

Question 24

What 4 factors is the rate of digestion in reptiles affected by?

Answer 24

• Type of food
• Energy demand
• Temperature
• Disease/illness

Question 25

In reptiles what does the large intestine terminate in?

Answer 25

The cloaca

Question 26

What are the 3 compartments of the cloaca?

Answer 26

Coprodeum - entered by GI tract
Urodeum - entered by bladder and repro organs
Protectodeum

Question 27

What is excreted in reptiles as the end product of protein metabolism?

Answer 27

Uric acid

Question 28

How do reptilian kidneys differ to mammalian?

Answer 28

• no loop of Henle
• no renal pyramids
• no renal pelvis
• located in caudal coelomic cavity

Question 29

Which reptilian species don’t have a bladder?

Answer 29

Snakes

Question 30

What are methods of water conservation in reptiles?

Answer 30

• minimal through kidneys
• cloacal reflux into colon
• uric acid excretion
• renal portal system
• reduced glomerular filtration

Question 31

Which ligament is not present in reptile dentition?

Answer 31

Periodontal ligament

Question 32

What are the 3 types of reptilian tooth?

Answer 32

• Acrodont: attached to the crest of the bone
• Pleurodont: attached to the medial aspect of the bone
• Thecodont: in a socket

Question 33

Reptilian teeth are continually replaced throughout life through a process called…?

Answer 33

Polyphydonty

Question 34

Describe the 2 reproductive strategies in reptiles

Answer 34

Oviparous: lay eggs that develop outside the body, fertilisation internal or external, yolk is source of nutrients
Viviparous: eggs hatched internally and young born ‘live’, some have placental like exchange

Question 35

Which gland has a role in light detection?

Answer 35

Pineal gland

Question 36

Olfaction is controlled by which organ? what does it detect?

Answer 36

Jacobson’s organ - detects pheromones

Question 37

What is the role of the parietal/third eye?

Answer 37

• no role in vision
• light detection
• found on top of head between lateral eyes
• modified scale