Chapter 20 - Reptiles/Amphibians (Final Creative Review)
Test yourself questions
Terms in this set (15)
What are the four orders of living reptiles?
The class Reptilia comprises four orders:
1. Crocodylia (alligators & crocodiles)
2.Squamata (snakes & lizards)
3.Chelonian (turtles & tortoises)
What are the three orders of amphibians?
The class Amphibia is made up of three orders:
2.Anura (frogs & toads)
3. Caudata (salamanders & newts)
Amphibians & reptiles are commonly referred to as ECOTHERMIC or COLD-BLOODED. Ectothermic animals are unable to generate body heat internally, therefore their body temps are dependent on environmental temperatures
What is a "preferred optimal temperature zone"?
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. This principle becomes very important when maintaining herptiles in captivity. If not provided with an appropriate thermal gradient, it will not be able to thermoregulate efficiently. When provided with inappropriately low temps, exothermic animals can suffer from digestive problems, immunosuppression & other disorders. If kept at temps that are to high, the animal is forced to maintain a high metabolic rate & may suffer from energy deficits
How does an exothermic animal main their body temps?
They maintain their body temps in an appropriate range through a process called BEHAVIORAL THERMOREGULATION, which allows amphibians & reptiles to precisely regulate their body temps according to metabolic need. Movement within the thermal gradient of their habitat as well as postural changes enable herptiles to adjust their body temps as needed. Ex., many herptiles "bask" to elevate body temps &seek shade when they need to cool down. A snake trying to conserve body heat coils tightly to decrease surface area & consequently heat loss, whereas a hot snake uncool to accomplish the opposite. Some animals can actually adjust the color &pattern of their skin to increase or decrease the absorption of thermal energy from the sun (chameleons)
Ecdysis in reptiles is under the control of what hormon?
Ecdysis is under the control of thyroid hormone
What is a "drink patch"
It is 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 amphibian skin allows them to absorb all the water they need from the environment, thus amphibians do not drink.
What reptiles have tapetum?
Crocodilians have a tapetum
How many cardiac chambers do noncrocodilian reptiles & amphibians have?
Amphibians & most reptiles have a three-chambered hearts with two artia & one common ventricle. The single ventricle functions as a four-chambered heart however, so oxygenated & deoxygentatec blood never mixes. Crocodilians are the only reptiles which possess four chambered hearts.
Right-to-left cardiac shunting serves what function in reptiles?
Right-to-left cardiac shunting aloows reptiles to survive in times of O2 deprivation(diving in some reptiles, consumption of large prey in snakes). Right-to-left cardiac shunting is facilitated by an increase pulmonary vascular resistance. Resumption of breathing results in a decrease in pressure within the pulmonary vasculature & restoration of pulmonary blood flow.
What is the main difference between a heterophil & a neutrophil?
Heterophils differ from neutrophils in that they do not posses periodase & acid phosphatase, which are enzymes involved in breaking down necrotic material
What is the function of a lymph heart?
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 result in relatively frequent lymph contamination of samples during venipuncture
Which reptile have complete cartilaginous tracheal rings.
Chelonians possess complete cartilaginous tracheal rings
Where does gas exchange take place in the reptilian lung?
Macroscipically, the pulmonary tissue of amphibians & reptiles has a honeycomb appearance. The openings of the honeycomb terminate in gas exchange structures call FAVEOLI. Unlike mammalian alveoli, the faveoli are fixed structures & do not expand or contrast. The faveoli are surrounded by capillary beds where the blood takes up O2 & releases CO2
Describe the three different lungs morphologies found in reptiles?
The are three distinct lung morphologies in reptiles. The first is the UNICAMERAL lung (most primitive), which is found in snakes & some lizards. It is simple sac-like structure. Typically, the cranial portion contains the tissues involved in gas exchange, & the relatively avascular caudal portion is comparable to the avian air sac. The second is the MULTICAMERAL lung, found in chelonians, some lizards, & crocodilians. It is divided into many compartments & posses intrapulmonary bronchi. The third has an intermediate lung morphology & is called PAUCICAMERAL lung. It shares characteristics of both unicameral & multicameral & is found most notably in iguanas & chameleons.