Test Yourself Ch 22

Front 1

What are the four orders of living reptiles? what are the three orders of amphibians?

Back 1

(1)Crocodylia (alligators and crocodiles)

(2) Squamata(snakes and lizards)

(3) Chelonian (turtles and tortoises)

(4) Rhynchocephalia(tuataras).

(1) Gymnophiona (caecilians)

(2) Anura (frogs andtoads)

(3) Caudata (salamanders and newts).

Front 2

Define ectothermic.

Back 2

Amphibians and reptilesare commonly referred to as ectothermic or cold blooded.

Ectothermic animals are unable to generate body heat internally; therefore,their body temperatures are dependent on environmental temperatures.

Front 3

What is a preferred optimal temerature zone?

Back 3

An ectotherm’s ability to effectively thermoregulate is entirely dependent on access to temps within the animal’s preferred optimal temp zone (POTZ), which is a range of temps in which the animal can perform all necessary metabolic functions. When provided with inappropriately low temps, ectothermic animals can suffer from digestive problems,immunosuppression, and other disorders. If kept at temps that are too high, the animals are forced to maintain a high metabolic rate and may suffer from energy deficits.

Front 4

How does an ectothermic animal maintain an appropriate body temperature?

Back 4

through a process called behavioral thermoregulation, which allows amphibians and reptiles to precisely regulate their body temps according to metabolic need. Movements within the thermal gradient of their habitat as well as postural changes enable herptiles to adjust their body temps as needed. For instance, many herptiles bask to elevate body temps and seek shade when they need to cool down. Some animals can actually adjust the color and pattern of their skin to increase or decrease the absorption of thermal energy from the sun

Front 5

Ecdysis in reptiles is under the control of what hormone?

Back 5

Ecdysis is under the control of thyroid hormone.

Front 6

What is a drink patch?

Back 6

an area of the skin with increased permeability. It is usually present on the ventral surfaces that most frequently come in contact with water. The extremely permeable nature of amphibians’ skin allows them to absorb all the water they need from the environment; thus amphibians do not drink.

Front 7

Which reptiles have a tapetum?

Back 7

Crocodilians

Front 8

How does the reptile iris differ from that of mammals?

Back 8

Reptiles are similar to birds in that the iris is made up of skeletal muscle and is under voluntary control. In mammals, the irisis under involuntary control. Therefore, mydriatic agents used to dilate the pupil for ophthalmic examinations in mammals are not effective in reptiles. Adirect pupillary light response is usually noted, but consensual reflexes are often not seen.

Front 9

The nasolacrimal duct system is absent in what order of reptiles?

Back 9

Chelonians do not possess nasolacrimal ducts. The tears spill over the lid margin, so some degree of epiphora is normal in healthy animals.

Front 10

How many cardiac chambers do non-crocodilian reptiles and amphibians have?

Back 10

Amphibians and most reptiles have three-chambered hearts with two atria and one common ventricle. The single ventricle functionsas a four-chambered heart, however, so oxygenated and deoxygenated blood nevermixes. Crocodilians are the only reptiles that possess four-chambered hearts.

Front 11

Right-to-left cardiac shunting serves what function in reptiles?

Back 11

allows reptiles to survive in times of oxygen deprivation(diving in some reptiles or consumption of large prey in snakes). Right-to-leftcardiac shunting is facilitated by an increase in pulmonary vascular resistance. Resumption of breathing results in a decrease in pressures within the pulmonary vasculature and restoration of pulmonary blood flow.

Front 12

What is the main difference between a heterophil and a neutrophil?

Back 12

Heterophils differ from neutrophils in that they do not possess peroxidase and acid phosphatase,which are enzymes involved in breaking down necrotic material.

Front 13

What is the function of a lymph heart?

Back 13

Lymph hearts are areas of lymph vessels that contain smooth muscle. Their purpose is to actively pump lymph through the vasculature. The presence of the large lymph vessels in association with blood vessels results in relatively frequent lymph contamination of samples during venipuncture.

Front 14

Which reptiles have complete tracheal rings?

Back 14

Chelonians possess complete cartilaginous tracheal rings.

Front 15

Where does exchange take place in the reptilian lung?

Back 15

Macroscopically, the pulmonary tissue of amphibians and reptiles has a honeycomb appearance. The openings of the honeycomb terminate in gas exchange structures are called faveoli. Unlike mammalian alveoli, the faveoli are fixed structures and do not expand or contract. The faveoli are surrounded by capillary beds, where the blood takes up oxygen and releases carbon dioxide.

Gas exchange can also occur across the mucous membranes of the buccal cavity and pharynx. Many aquatic chelonians are also capable of exchanging gases across the mucousmembranes of the pharynx and cloaca.

Front 16

Describe the three different lung structures found in reptiles.

Back 16

1.unicameral lung (themost primitive), which is found in snakes and some lizards. It is a simple sac like structure. Typically, the cranial portion contains the tissues involved in gas exchange, and the relatively avascular caudal portion is comparable to the avian air sac.

2 multicameral lung, found in chelonians,some lizards, and crocodilians. It is divided into many compartments andpossesses intrapulmonary bronchi.

3. has an intermediate lungmorphology and is called the paucicameral lung. It sharescharacteristics of both the unicameral and multicameral and is found mostnotably in iguanas and chameleons.

Front 17

What is the name of the single bone found within the middle ear of a reptile?

Back 17

The columella

Front 18

Which reptiles do not have external ear openings?

Back 18

Snakes do not have external ear openings. Salamanders and caecilians do not have tympanic membranes.

Front 19

What is the function of a vomeronasal organ?

Back 19

The vomeronasal organ is an accessory olfactory organ. Snakes and lizards, such as monitors and tegus, have tongues that are deeply forked and function as a particle delivery system for the vomeronasal organ.

Front 20

Name the different types of dentition found in reptiles.

Back 20

1 codont- teeth arising from sockets in the skull bones, is foundonly in crocodilians.

2 pleurodont-attached to the periosteum on the medial aspects of both the mandibles and maxillae.

3 acrodont- teeth fused to the biting edge of the mandible and maxillae, is foundin some species of lizards, such as those in the family Agamidae.

The codont and pleurodont teeth are replaced periodically during the life of the animal, whereas acrodont teeth do not growback if lost or broken.

Front 21

Which amphibians do not have teeth?

Back 21

Bufonid toads do not have teeth.

Front 22

What herptiles are capable of gastric prolapse as a method of emptying their stomachs?

Back 22

Anurans are capable of gastric prolapse.

Front 23

Given that reptiles are unable to produce concentrated urine, how do they conserve water?

Back 23

absorb additional water from the urine through the wall of the urinary bladder, rectum, or cloaca, resulting in voided urine that is somewhat concentrated. Terrestrial reptiles produce uric acid asa protein waste product. Uric acid is relatively insoluble in blood and isvoided via secretion from the renal tubules. Because uric acid is secretedrather than filtered, very little urine is needed to excrete it from the body.

The renal portal systemalso allows water conservation. The renal portal veins arise from the veins ofthe tail and hind limbs if present. The renal portal vessels lead to capillarybeds that perfuse the renal tubules but bypass the glomeruli. This anatomicconfiguration allows the reptile to discontinue blood flow to the glomeruli anddecrease urine production during times of dehydration while maintaining bloodflow to the renal tubules. Because blood flow to the tubules is maintained,ischemic necrosis is avoided and uric acid secretion continues.

Front 24

What nitrogenous waste products are produced most frequently by aquatic amphibians? What nitrogenous waste products are produced by terrestrial amphibians?

Back 24

Terrestrial amphibians produce uric acid, and aquatic or semi-aquatic reptiles produce ammonia and/or urea.

Front 25

What is the purpose of the renal portal system?

Back 25

conserve water. It allows the reptile to discontinue blood flow to the glomeruli and decrease urine production during times of dehydration while maintaining blood flow to the renal tubules.

Front 26

Where do the ureters terminate in reptiles and amphibians?

Back 26

The ureters empty into the dorso lateral aspects of the urodeum instead of the urinary bladder.The urinary bladder, if present, is connected to the urodeum by a short, broad urethra. The urine enters the bladder for storage through the urodeum. It is important to note that crocodilians, snakes, and some species of lizards do not possess urinary bladders.

Front 27

How is sex determined in reptiles that do not possess sex chromosomes?

Back 27

Sex in reptiles is determined by either genotype or the temperature at which eggs are incubated. Sex chromosomes are not present in species such as crocodilians, chelonians, tuataras, and some lizards;therefore, egg incubation temperature determines the sex of the hatchling. In general, higher incubation temperatures produce males and lower temperatures produce females in crocodilians and lizards. The opposite occurs in chelonians. In nature there is typically a temp range within the nest that allows the production of a mixed clutch of male and female hatchlings. Reptiles that possess sex chromosomes differ from mammals in that the females are the heterozygous sex (ZW) and males are homozygous (ZZ).

Front 28

What are the names of the male copulatory organs in snakes and lizards?

Back 28

Hemipenes

Front 29

Describe the process of fertilization in salamanders.

Back 29

Internal fertilization occurs in most salamanders. Male salamanders deposit packets of sperm called spermatophoresonto substrate, which are subsequently picked up by the female salamander’s cloaca. Female salamanders can store sperm for extended periods of time in pockets within the cloaca called spermatotheca.

Front 30

What is vitellogenesis?

Back 30

The process of adding vitellogenin, a lipid substance, to the yolk within the developing follicle. When certain environmental cues are encountered, estrogen and follicle-stimulating hormone are released, which causes development and maturation of the follicles via a process called vitellogenesis. Vitellogenin is formed from mobilized fat by the liver; thus during vitellogenesis the liver often takes on a yellow color. Large amounts of calcium are also added to the yolk during this process.Circulating calcium levels tend to be very high in reptiles during vitellogenesis because calcium is mobilized by bone to supply the developing follicles.

Front 31

What adaptations are found in the snake skull that allow the ingestion of large prey?

Back 31

The mandibularsymphysis is not fused in snakes, but instead connected by ligaments. This flexible connection of the rostral mandibles allows the jaws to move independently of one another and literally “walk” forward when prey are ingested.Other adaptations include the presence of the quadrate bones, which allow the mouth to open very wide, and movable bones that make up the maxillae and palate.

Front 32

What is tail autonomy?

Back 32

Tail autonomy is a defense mechanism of many lizard and salamander species. Tail autonomy allows lizards to drop their tailswhen being pursued or attacked by a predator. The discarded tail usually continues to wiggle about, which is intended to draw the attention of the attacker while the lizard makes its escape. The tails of lizards capable of autonomy have fracture planes along which they break. When tails are lost viaautonomy, there is usually little to no blood loss because the muscles of thetail strongly contract and the blood vessels are occluded. The lost tail can regenerate with a stiff cartilaginous rod replacing the spine. The regenerated tail is usually smaller and stiffer than the original in lizards. Usually the regenerated tail of a salamander very closely resembles the original

Front 33

What is unique about the attachment between the skull and cervical spine of a reptile?

Back 33

There is a single occipital condyle that forms the articulation between the skull and spine. This allows increased mobility of the head on the spine but also makes this connection relatively fragile, necessitating care when restraining reptiles.

Front 34

Why are reptiles unable to sustain physical activity for long periods of time

Back 34

Reptilian muscles are incapable of sustained aerobic metabolism and switch quickly to anaerobic metabolism with prolonged physical exertion. Anaerobic metabolism is less efficient than aerobic metabolism and results in rapid buildup of lactate. Lactate decreases the pH of the blood and tissues and is metabolized slowly by reptiles. For this reason, reptiles are unable to sustain physical activity and are capable of only short bursts.