Reptile normal structure and function 2 Flashcards
1
Q
What is the order that includes tortoises, terrapins and turtles?
A
Chelonia
2
Q
Approximately, how many described species of Chelonia exist?
A
294
3
Q
What are the 2 suborder of Chelonia?
A
Pleurodira
Cryptodira
4
Q
Which feature determines the sub-order a species of Chelonia is placed in?
A
Pleurodira = snake neck and side neck turtles. Flex neck at 3 points (S-shape horizontally). Head cannot be fully drawn into shell.
Cryptodira = everything else. Flex head at 2 points (S-shape vertically). Head fully drawn into shell.
5
Q
How do Chelonia thermoregulate?
A
Gain heat by basking in the sun = heliothermic
6
Q
What can the shell sometimes affect in Chelonia in regards to thermoregulation?
A
Shell can hamper cooling
7
Q
What will subtropical and temperate species of Chelonia do in response to decreasing temperatures?
A
Hibernate/Brumation
8
Q
What is the shell composed of in most species of Chelonia?
A
Composed of keratinised plaster called scutes
9
Q
In terrestrial tortoises, how does shell growth occur?
A
Scutes are not normally shed.
Grow by adding additional keratin at the base.
10
Q
In some turtles, how does shell growth occur?
A
Scutes are shed or peel away to make room for new scutes
11
Q
How did the Chelonia get their shells?
A
As they came onto land from water, they needed more musculature to walk so the spine and ribs fused.
12
Q
What is the dorsal domed part of a Chelonia shell called?
A
Carapace
13
Q
What is the ventral flattened part of a Chelonia shell called?
A
Plastron
14
Q
What do the scutes overlie in Chelonia?
A
Scutes overlie dermal bone plates
15
Q
What are the scutes of Chelonia shells supplied with?
A
Blood vessels and nerves
16
Q
What are the major modifications of the skeleton of Chelonia?
A
Limbs project laterally
Spine and ribs fused
Pectoral and pelvic girdle vertical within ribcage
17
Q
What kind of breathers are Chelonia?
A
Nasal breathers
18
Q
Describe the trachea of Chelonia and what this results in.
A
The trachea is short.
Allows them to keep breathing when head is retracted into shell
19
Q
What respiratory system feature do Chelonia lack?
A
Diaphragm
20
Q
How do Chelonia alter internal pressure within the body?
A
Movement of limbs and head help to alter internal pressure within the body and assist respiration
21
Q
Where are the lungs found in Chelonia?
A
Lungs lie dorsally under carapace
22
Q
What aids buoyancy in aquatic species of Chelonia?
A
The position of the lungs - dorsal under carapace
23
Q
Can Chelonia respire anaerobically?
A
They can switch to anaerobic respiration for long periods (breath holding)
24
Q
How many chambers in the Chelonia heart?
A
3 - no septum in ventricles
25
Where does the heart lie in Chelonia?
Posterior to pectoral girdle
26
How do you listen to a Chelonias heart beat?
Doppler probe and ultrasound
Damp towel and stethoscope
27
Where do you take a blood sample from Chelonia?
Jugular vein - if neck is out
Dorsal coccygeal vein
28
Describe the diet of Chelonia.
25% of species completely herbivorous
Others are omnivorous but prefer slow prey
29
How do Chelonia eat their food?
No teeth - use sharp beak instead
Use the thick fleshy tongue
30
Describe the gastrointestinal system of Chelonia.
Simple stomach, lies near large bilobed liver. Short small intestine. Colon large in herbivores and caecum distinct.
31
How long can digestion take in Chelonia?
Slow - 2-4 weeks transit time
32
Where are the kidneys located in Chelonia?
Under caudal carapace
33
Describe the kidneys of Chelonia.
Lobulated
No loop of Henle and no renal pelvis (lose water through blood)
34
What is excreted from the urinary system in Chelonia?
Urea or uric acid
Different excretion patterns in different species
35
How is urine excreted in Chelonia?
Urine can be excreted directly into urodeum, or refluxed into either 'bladder' (pouch) or colon for further water conservation
36
What can dehydration in Chelonia lead to?
Dehydration
37
Describe the male reproductive system of Chelonia.
Single phallus which protrudes form proctodeum (not involved in urination).
Testes in caudal coelomic cavity, just cranial to kidneys.
38
How can you identify a male Chelonia?
Concave plastron to assit mounting.
Presence of phallus
Longer distance from caudal edge of plastron to cloaca than females.
Longer, broader tails than females
39
Describe the female reproductive system of Chelonia.
Paired ovaries and oviducts.
Similar anatomy to birds, ova travel down reproductive tract and egg is formed.
40
Are Chelonia oviparous or viviparous?
Oviparous
41
How can you identify a female Chelonia?
Flat plastron
Shorter distance between caudal carapace and cloaca than males.
42
What is the order of lizards?
Squamata
43
What is the suborder of lizards?
Lacertilia
44
Around how many species are in the Squamata Lacertilia?
1000 described species
Variable in size and lifespan
Widely distributed throughout the world
45
What are the four recognised infraorders within the suborder Lacertilia and which animals do they include?
Iguania - iguanas, anoles, water and bearded dragons, chameleons
Gekkota - geckos
Scincomorpha - tegus and skinks
Varinoidea - Cila moster, komodo dragon, monitor lizards
46
How can lizards thermoregulate?
Species dependent
Colour change
Body position/posture
Behaviour
47
Describe the integument of most species of lizards.
Heavily keratinised
Skin waterproof
48
What features of integument are present in some species of lizards and what are they for?
Spines or horns - used as defence mechanism
Skin flaps - used in courtship
49
Describe the healing of skin in reptiles.
Slow
50
Describe ecdysis in lizards.
Ecdysis occurs at regular intervals
More regular with rapid growth
51
What is a kinetic skull and what does it allow for in lizards?
Moveable
Allows wider gape
52
Describe the muscles in lizard jaws.
Strong
Pterygoideus and external adductor muscle main jaw closers
Depressor mandible is main jaw opener
53
What is unique about the ribs of lizards?
There is a rib on all vertebrae except cervical
54
In which kind of lizards are the limbs not well developed?
Burrowing lizards do not have well developed limbs. All others do.
55
What position are the limbs directed in primitive lizards compared to more specialised lizards?
Primitive lizards - limbs directed laterally
More specialised - limbs directed like mammals
56
Describe the vertebrae found within a lizards tail.
Often more post sacral than pre-sacral vertebrae
57
What is the tail a site for in many lizards?
Fat storage
58
What is a defence mechanism in lizards?
Tail can be shed - autotomy
59
What are large volume lungs of lizards also used for?
Buoyancy, display and vocalisation as well as respiration.
60
Describe the position of the glottis in lizards.
Glottis is closed except during inspiration and expiration
61
Due to the lack of diaphragm, what do lizards rely on for respiration and what does this increase the chance of?
Rely on respiratory muscles
Increases chance of lung infection
62
What are the 3 lung types found in lizards?
Unicameral, paucicameral, multicameral
63
How many chambers in a lizards heart?
3
64
Where is the heart found in lizards?
Pectoral inlet in most species
More caudal in advanced lizards
65
Where do you take blood samples from lizards?
Ventral coccygeal (tail) vein caudal to cloaca
Axillary venous plexus
ventral abdominal vein (fragile)
66
Describe the gastrointestinal system of omnivorous and insectivorous lizards.
Short and simple
67
Describe the gastrointestinal system of herbivorous lizards.
Hindgut fermenters
Micro-organisms and high ambient temperature required for fermentation
68
Describe the kidneys of lizards and where they are located.
Lobulated
In caudodorsal celom
69
How is urine excreted/stored in lizards?
Urine enters the urodeum (via the ureters)
Can reflux into bladder or coprodeum for further water absorption
70
What adaptation of herbivorous lizards have within the urinary system?
High potassium diets
Have salt glands which are an additional route for excretion
71
Describe the male reproductive anatomy of lizards.
Testes are abdominal.
Paires hemipenes stored in tail base
72
How does a male lizard mate with a female?
Only one hemipene is used in each copulatory event
Engorges and protrudes through cloaca
73
What can often happen in male lizard reproductive systems that may require surgery?
Hemipenes will often prolapse
Can be surgically removed if problematic
74
Describe the female reproductive anatomy of lizards.
Paired ovaries and oviducts (long and pleated)
75
What issues may occur in female lizard reproductive systems?
Mature oocytes that fail to ovulate can remain in ovary = follicular stasis
Ovulated oocytes may remain in oviduct = egg binding
76
What are the reproductive strategies of female lizards?
Oviparous
Viviparous
Parthenogenesis
77
How can you sex lizards?
Males:
- larger, more colourful
- presence of prominent dewlaps, crests and spines
- have prominent femoral pores on thigh area
- cloacal bulge (site of hemipenes)
78
What can often make sexing lizards difficult?
Male lizards can evert their hemipenes
79
What can often be used to sex lizards?
Probe (not as useful)
Radiography, endoscopy, ultrasound
80
What is the order and suborder of snakes?
Squamata
Serpentes
81
Around how many species of snake are there?
3000
82
What are the 4 families of snakes called? Which of these are you most likely to see in practice?
Viperidae
Elapidae
Colubridae
Boidae
Colubridae and Boidae are likely to be seen in practice
83
What is thermoregulation in snakes based on?
Behaviour
84
What behaviour is used to gain heat in snakes?
Basking
85
What behaviour is used to retain heat in snakes?
Coiling
86
What behaviour is used to prevent heat gain in snakes?
Hiding in shade
87
What behaviour is used to lose heat in snakes?
Uncoiling
88
Describe the integument of snakes and what this allows them to do.
Scales, joined by small folded areas of skin.
Allows expansion of the integumentary when eating a large meal
89
Where is the pigment of a snake found?
Subnormal layer
(transparent shell)
90
Why is ecdysis important in snakes and what is it?
It is important to allow growth.
Shed entire skin including spectacles
91
Describe the lungs of snakes.
Right lung = huge
Left lung = residual
92
What is found in the cranial 1/3 of a snake?
Heart, trachea, oesophagus, thyroid, proximal lung
93
What is found in the middle 1/3 of a snake?
Stomach, liver, lung, spleen, pancreas
94
What is found in the caudal 1/3 of a snake?
Intestines, kidneys, gonads
95
What features of the skull are absent in snakes?
Middle ear cavity
Mandibular symphysis
96
What allows the independent movement of the upper and lower jaws in snakes?
Kinetic skull
Loose jaw articulation
'Walk' over prey
97
What do some snakes have remnants of?
Hindlimbs
98
Which vertebrae lack ribs in snakes?
First and second cervical vertebrae
99
How many pre-cloacal vertebrae can snakes have?
Up to 400, all with a pair of ribs
100
What are the various methods of locomotion found amongst snakes depending on their species?
Lateral undulation (typical side to side movement)
Rectilinear (shorten length of body then extend)
Concertina (move head forwards and body follows in concertina)
Sidewinding (move head at angle and body twists as it follows)
101
How many chambers in a snake heart?
3 chambers (2 atria, 1 ventricle)
102
Where is the heart located in snakes?
Approximately 1/3rd down the body
103
Describe the glottis of snakes and what this results in.
Glottis is rostral - avoids occlusion while swallowing
104
What respiratory organ do snakes lack? What reflex does this prevent? What does this make snakes susceptible to?
No diaphragm
Poor cough reflex
Susceptible to pneumonia
105
Is respiration in snakes passive or active?
Passive and active respiration
Strong intercostal muscles
106
What are teeth used for in snakes?
Prehension of food
Don't chew, just swallow
107
What kind of teeth do snakes have?
Pleurodont teeth
108
What is unusual about the maxillary teeth in snakes?
Can be modified into fangs
Often 2 rows of teeth
109
Describe the position of the tongue of a snake.
Lies in sheath below glottis, can protrude through lingual notch without opening mouth
110
What is the tongue used for in snakes?
Touch, taste, olfaction
111
What assists food moving through the body of a snake?
Axial muscles
112
In what species of snake is a caecum present?
Some boidae only
113
What is the role of the stomach in snakes?
Role in food storage (along with oesophagus)
Mainly digestion - rapid but absorption poor
114
What feature of the stomach is poorly developed in snakes?
Cardiac sphincter
115
Describe the liver of snakes and what its role is.
Elongated liver, with gall bladder.
For fat digestion
116
Where are the kidneys located in snakes?
Dorsal caudal abdomen
117
Describe the kidneys of snakes.
Lobular
10-15% of nose to cloacal length
118
Where do the ureters of snakes enter into?
Directly into the cloaca
119
What part of the urinary system is absent in snakes?
No bladder
Some species have small dilations of distal ureter
120
What is unique about male snake kidneys?
Males have sexual segment to kidney
The secretions form copulatory plug
121
At what age do snake reach sexual maturity?
Around 1-5 years (size dependent) (bigger snakes take longer)
122
Describe the male reproductive system of snakes.
Two intra abdominal testes, cranial to kidneys.
Paired hemipenes - everted singly during mating
123
Describe the female reproductive system of snakes.
Oviparous or viviparous
Two ovaries - some species have lost one
Ability to store sperm for years
124
How do you sex a snake?
Tail base is broader in males (due to hemipenes)
Eversion of hemipenes
Probing cloaca (6-10 scales in males, 2-3 scales in females)
125
As well as the regular methods, how can you also sex boids?
Longer tail in male than female
Males have larger spurs (vestigial remnant of pelvis)
126
What is the most well developed sense in snakes?
Olfaction
127
What do snakes also have in addition to normal olfactory cells?
Jacobsens organ
128
How is scent sensed in the tongue of snakes?
Forked tongue pills up scent molecules and delivers them directly into the pits
129
Describe the eye of snakes and what this results in for sight.
Limited movement of eye, reduced ciliary body.
No nictitating membrane
Eyelids fused for form 'spectacle'
Sight is poor
130
Describe the quality of hearing of snakes.
Good detection of low frequency sounds only.
131
How do snakes hear?
Vibrations picked up by quadrate bone and passed to ear/brain for processing
132
Describe the anatomy of a snakes ear.
No external ear, but well developed inner ear
133
How do snakes have the ability of thermoreception?
Infrared sensors, between eye and nostril
134
What does thermoreception allow snakes to do?
Detect warm blooded prey in complete darkness.
