Anatomy and physiology of amphibians

Question 1

Most commonly kept species in terrariums (5)

Answer 1

Amphibians
Tortoises and turtles
Snakes
Lizards
Tarantulas

Question 2

The class name Amphibia (derived from the
Greek roots amphi, meaning “both,” and
bios, translated as “life”), refers to

Answer 2

the dual stages of life: aquatic and terrestrial.

Question 3

Most amphibian species have aquatic..?

Answer 3

larval forms

Gas exchange occurs in external gills.

Metamorphosis to the adult, usually a terrestrial form, results in the development of lungs.

Question 4

Amphibian lungs are

Answer 4

Primitive lungs that are relatively inefficient compared to those of other terrestrial vertebrates.

Respiration is supplemented by gas exchange across the skin. Secretions of the highly glandular skin help to maintain a moist exchange surface.

Question 5

Reproduction type of Most amphibians are

Answer 5

oviparous, similar to fish and most
reptiles.

Though their eggs must not be laid in completely aquatic environments, the ova lack the water-resistant membranes or
shell of reptile and birds’ eggs.

Question 6

Amphibians are classified into three orders:

Answer 6

Anura: frogs and toads
Caudata: salamanders, newts
Gymnophiona : caecilians

Question 7

The have either a very poorly developed tail or lack one and the larvae are unlike the adults.

What order is this?

Answer 7

Order Anura: frogs and toads

Question 8

They have a long tail, with the toothed larval
forms often being similar in appearance to the adults.

What order is this?

Answer 8

Caudata : salamanders, newts, and sirens

Question 9

What is a siren?

Answer 9

The greater siren is an amphibian and one of the three members of the genus Siren.

Question 10

They are limbless, with elongate worm-like
bodies, and short or absent tails.

What order is this?

Answer 10

Gymnophiona: caecilians

Question 11

They are lizard-like in form, covered in glandular skin.
Their range in total length can be 4 cm-1.5m.

What amphibian does this describe?

Answer 11

Salamanders

Question 12

Are tail-less as adults.
The glandular skin may be smooth or bosselated.
Length can be 1–30 cm.

What amphibian does this describe?

Answer 12

Frogs and toads

Question 13

They are limbless and resemble a snake or worm.
They have a very short tail, if one is present at all.
Total length can be 7.5–75 cm.

What amphibian does this describe?

Answer 13

Caecilians

Question 14

Describe skeletal system of salamanders.

Answer 14

Typically have four limbs, hindlimbs in some species are reduced or missing.

Four toes on the forefoot and five on the hind.

Salamanders are capable of regenerating lost toes, limbs and tail.

Question 15

Describe skeletal system of caecilians.

Answer 15

Lack pectoral and pelvic girdles and the sacrum.

Locomotion is primarily achieved through worm-like regional contraction of the body or lateral eel-like undulations.

Question 16

Describe skeletal system of frogs & toads.

Answer 16

Have four limbs, the hind legs are elongated.
Four toes on the forefoot and five on the hind foot. The vertebrae are fused.

The sacrum is not present, and the pelvic girdle is fused.

The forelimb is composed of the humerus, a fused radio-ulna, carpals, metacarpals, and phalanges.

The hind limb is formed by the femur, fused tibiofibula, tarsals, metatarsals, and phalanges.

Caudal vertebrae are replaced by a fused urostyle.

Tadpoles can regenerate limbs, but adult anurans generally cannot.

Question 17

The amphibian heart is

Answer 17

3-chambered, with two atria and one ventricle.

The interatrial septum is fenestrated in
caecilians and most salamanders, but
complete in anurans (toads/frogs). Allowing varying degrees of mixture of
oxygenated and deoxygenated blood.

Question 18

Blood draining from the caudal half of
amphibians passes through

Answer 18

the kidneys prior to entering the postcaval vein.

Question 19

Amphibian lymph consists of

Answer 19

all the components of blood, with the
exception of erythrocytes.

Question 20

The amphibian lymphatic system includes

Answer 20

lymph hearts (lymph sacs or lymph vesicles).

They beat independently of the heart
at a rate of 50–60 beats per minute.

These structures ensure unidirectional flow of lymph back to the heart.

Question 21

In amphibians, gas exchange always occurs

Answer 21

across a moist surface.

Cutaneous respiration is important in both larval and adult forms.

Larval amphibians utilize gill structures for respiration and adults use lungs.

Question 22

Three modes of respiration described in adult caecilians and anurans (toads/frogs):

Answer 22

pulmonic, buccopharyngeal and cutaneous.

Question 23

Most terrestrial salamander species have gills or lungs?

Answer 23

lose their gills and develop lungs
like anurans.

Question 24

The lungs of amphibians are

Answer 24

simple saclike structures that lack true
alveoli.

Question 25

Amphibians lack a diaphragm so they instead rely on

Answer 25

coordinated movements of their axial and appendicular muscles for gas exchange in the lungs. During periods of reduced oxygen availability amphibians may switch to cutaneous respiration. Cutaneous respiration is not as efficient as pulmonic respiration so many amphibians have developed specialized integumentary structure.

Question 26

What type of amphibian is herbivorous?

Answer 26

Many larval amphibians are herbivorous . Adults are entirely carnivorous, with a wide variety of invertebrates constituting a large part of the diet.

Question 27

Caecilians rely primarily on olfactory cues to locate prey, whereas salamanders and anurans use

Answer 27

sight as the prominent sense for food detection. The tongue of most anurans and salamanders can be extended beyond the mouth for food capture.

Question 28

What type of amphibian is prone to Gastric overload, impaction and ingestion of non-food items (substrate gravel or moss)?

Answer 28

Anurans (toads/frogs) in particular are voracious feeders and tend to eat anything that fits in their mouth.

Question 29

Amphibian feces are expelled into the

Answer 29

cloaca.

Question 30

Describe amphibian kidneys.

Answer 30

Amphibians have mesonephric kidneys that are unable to concentrate urine above the solute concentration of the plasma. Larvae and most aquatic adults excrete ammonia through the kidneys, skin, and gills. Terrestrial species convert toxic ammonia to less toxic urea in the liver. Urea can be stored in the bladder and excreted when water is readily available.

Question 31

Describe amphibian Urogenital system.

Answer 31

Amphibians have paired ovaries or testes. Sexual dimorphism is present in some amphibians. Depending on the species, breeding season may be influenced by temperature, rainfall, or changes in day length. Caecilians copulate and fertilize internally. Majority of the salamanders are internal fertilizers. The males deposit sperm packets on the substrate. The female picks up these packets through the cloacal opening and they are stored in the cloaca until egg laying. The amount of eggs depends from the species. Incubation duration varies from hours to several months.

Question 32

Ecdysis is

Answer 32

the process of an arthropod moulting its exoskeleton. Amphibians and reptiles shed layers of old, dead skin in large, visible pieces, some molting the entire old skin in one piece. This process is called ecdysis too. The thyroid gland is responsible for the control of ecdysis.

Question 33

Describe the amphibian nervous system.

Answer 33

As with vertebrates amphibians have central and a peripheral nervous system. The brain is slightly more evolved than that of a fish.

Question 34

Describe amphibian hearing.

Answer 34

Auditory structures vary greatly among amphibians. In many amphibian species, low-frequency sounds are transmitted to the inner ear by an opercular bone that receives the vibrations from the forelimbs. Taste, touch, olfaction are well developed in amphibians.

Question 35

Describe amphibian sight.

Answer 35

Ocular structures are well developed in amphibians. Except caecilians and some salamanders. Taste, touch, olfaction are well developed in amphibians.

Question 36

Amphibians also possess a unique sense organ known as

Answer 36

Jacobson’s organ. It is responsible for the detection of airborne chemicals( pheromones).

Question 37

The amphibian dermis contains numerous glands that produce

Answer 37

toxic or irritating substances as protective mechanisms. Many of the glandular secretions of amphibians can be irritating to the mucous membranes or even toxic. True scales and claws are lacking in amphibians.