8/13/13 7:53 AMCh 40 HW Page 1 of 18http://session.masteringbiology.com/myct/assignmentPrintView?assignmentID=2133932 Ch 40 HW Due: 12:00pm on Tuesday, August 13, 2013 You will receive no credit for items you complete after the assignment is due. Grading Policy Activity: Connective Tissue Click here to complete this activity. Then answer the questions. Part A How does connective tissue differ from the other three major tissue types? ANSWER: Correct This describes many connective tissues, such as loose connective tissue. Part B Which of these describes loose connective tissue? ANSWER: Correct Loose connective tissue is a packing material that serves, for example, to hold organs in place. Part C Cartilage is found _____. Connective tissue often consists of relatively few cells embedded in an extracellular matrix. Connective tissue consists of contractile proteins. Connective tissue consists of cells capable of transmitting electrical impulses. There are three types of connective tissue. Connective tissue is found lining body surfaces. It is a loose weave of fibers that functions as a packing material. It is composed of many fibers that connect bone to bone and muscle to bone. It is a rigid material that provides structural support. It transports nutrients and gases from one part of the body to another. It plays a role in padding, insulation, and energy storage. 8/13/13 7:53 AMCh 40 HW Page 2 of 18http://session.masteringbiology.com/myct/assignmentPrintView?assignmentID=2133932 ANSWER: Correct The ends of long bones, such as the femur, have a cartilage cap. Part D _____ is the connective tissue specialized for transport. ANSWER: Correct Blood is specialized for the transport of substances such as nutrients, wastes, and gases. Activity: Epithelial Tissue Click here to complete this activity. Then answer the questions. Part A What type of epithelium would you expect to find covering a surface subject to physical forces? ANSWER: surrounding organs such as the kidneys in the heart at the ends of bones such as the femur covering the surface of your body connecting one bone to another Bone Blood Adipose tissue Muscle tissue Cartilage 8/13/13 7:53 AMCh 40 HW Page 3 of 18http://session.masteringbiology.com/myct/assignmentPrintView?assignmentID=2133932 Correct Stratified epithelium consists of multiple layers; this thickness provides a protective barrier. Part B What type of epithelial tissue, found in the intestines, absorbs nutrients? ANSWER: Correct Simple columnar epithelium, such as that found lining the intestines, is specialized for absorption and secretion. Part C Which of these tissues, found in the lungs, permits gas exchange by diffusion? ANSWER: Correct This is a thin single layer of cells that allows for diffusion. Part D What type of epithelial tissue lines kidney tubules? ANSWER: simple epithelium squamous epithelium stratified epithelium simple cuboidal cells columnar epithelium stratified cuboidal epithelium simple cuboidal cells simple columnar epithelium stratified columnar epithelium stratified squamous epithelium stratified squamous epithelium simple cuboidal cells stratified cuboidal epithelium simple squamous epithelium simple columnar epithelium 8/13/13 7:53 AMCh 40 HW Page 4 of 18http://session.masteringbiology.com/myct/assignmentPrintView?assignmentID=2133932 Correct The simple cuboidal cells of kidney tubules allow for both secretion and absorption. Activity: Muscle Tissue Click here to complete this activity. Then answer the questions. Part A What type of muscle is responsible for contractions of the digestive tract and arteries? ANSWER: Correct Smooth muscle is responsible for the involuntary contractions of the digestive tract, arteries, and bladder. Part B Cardiac muscle is the only muscle composed of _____ fibers. ANSWER: stratified squamous epithelium stratified cuboidal epithelium simple squamous epithelium simple cuboidal cells stratified transitional epithelium smooth muscle skeletal muscle striated muscle voluntary muscle cardiac muscle 8/13/13 7:53 AMCh 40 HW Page 5 of 18http://session.masteringbiology.com/myct/assignmentPrintView?assignmentID=2133932 Correct Cardiac muscle fibers are branched. Part C _____ muscle is attached to bones. ANSWER: Correct Skeletal muscle is attached to bones. Activity: Nervous Tissue Click here to complete this activity. Then answer the questions. Part A A neuron consists of _____. ANSWER: branched unstriated unbranched and cylindrical spindle shaped striated Smooth Involuntary Cardiac Branched Skeletal 8/13/13 7:53 AMCh 40 HW Page 6 of 18http://session.masteringbiology.com/myct/assignmentPrintView?assignmentID=2133932 Correct These are the three regions of a neuron. Part B Nervous tissue functions _____. ANSWER: Correct This is one of the functions of nervous tissue. Activity: Regulation: Negative and Positive Feedback Click here to complete this activity. Then answer the questions. Part A Which of these is an example of negative feedback? ANSWER: a cell body only dendrites only axons only dendrites, a cell body, and axons striations as a physical barrier to the invasion of pathogens to physically move the body to sense stimuli to physically support the body in the absorption of nutrients 8/13/13 7:53 AMCh 40 HW Page 7 of 18http://session.masteringbiology.com/myct/assignmentPrintView?assignmentID=2133932 Correct Eating raises blood sugar levels; insulin stimulates the lowering of blood sugar level. In this example the response to the stimulus (increased blood sugar levels) opposes that stimulus (by lowering blood sugar levels). Activity: Homeostasis Click here to view this animation. Then answer the questions. Part A Which term describes a mechanism by which the internal conditions of an organism are kept at set values without regard to the external conditions? Hint 1. Which term describes a mechanism used by organisms to maintain a stable internal environment? ANSWER: Correct Regulatory homeostasis involves adjusting the internal conditions of an organism to set values without regard to the external conditions. Part B Which of the following actions is not a function of the epithelium? As a blood clot begins to form, the process of its formation gets faster and faster. After you eat, glucagon stimulates an increase in blood sugar levels. After you eat, insulin stimulates the lowering of blood sugar levels. The digestive enzyme pepsinogen is converted to pepsin by the action of hydrochloric acid; pepsin itself can then convert pepsinogen into pepsin. Once labor begins, contractions increase in frequency and intensity. Conformational homeostasis. Negative feedback. Thermoregulation. Regulatory homeostasis. 8/13/13 7:53 AMCh 40 HW Page 8 of 18http://session.masteringbiology.com/myct/assignmentPrintView?assignmentID=2133932 Hint 1. What are the functions of the epithelium? ANSWER: Correct The epithelium allows the internal environment to remain constant even if the external environment changes. Part C True or false? Organisms must maintain homeostasis because optimal enzyme activity is achieved within a very narrow range of conditions. Hint 1. What effects can suboptimal conditions have within a cell? ANSWER: Correct Enzyme activity depends on conditions within a cell, such as temperature and pH, which must be kept within a certain narrow range. Part D Which component of a homeostatic system sends instructions based on sensory information? Hint 1. This component is usually part of the brain or central nervous system. ANSWER: Correct An integrator sends instructions to an effector based on sensory information. Allows the internal environment to alter its conditions to match those of the external environment. Controls the exchange of nutrients between the internal and external environments. Regulates the excretion of waste. Creates an internal environment that is different from the external environment. True False Effector. Integrator. Set point. Sensor. 8/13/13 7:53 AMCh 40 HW Page 9 of 18http://session.masteringbiology.com/myct/assignmentPrintView?assignmentID=2133932 Part E Which component of a homeostatic system perceives changes in some parameter of the environment? Hint 1. In animals, this component is usually a nerve cell that detects a certain type of stimulus. ANSWER: Correct A sensor perceives changes in some parameter of the environment. Part F Which of the following actions acts to warm a homeothermic body? Hint 1. This action generates metabolic heat. ANSWER: Correct Shivering generates metabolic heat and warms the body. Part G Which of the following statements describes a negative feedback response? Hint 1. A negative feedback response opposes the change in internal conditions. ANSWER: Integrator. Set point. Effector. Sensor. Dilating blood vessels. Sweating. Panting. Shivering. The arrival of platelets at a wound site stimulates the recruitment of more platelets to form a clot. A person who loses 3 pounds continues to diet to lose an additional 10 pounds. After a meal, blood sugar levels in the body rise; insulin is secreted to lower blood sugar levels. The onset of contractions during childbirth stimulates the release of a hormone that stimulates further contractions. 8/13/13 7:53 AMCh 40 HW Page 10 of 18http://session.masteringbiology.com/myct/assignmentPrintView?assignmentID=2133932 Correct The actions of insulin reverse the internal conditions of high blood sugar levels in the body. Thermoregulation Thermoregulation is the maintenance of the body's temperature within a tolerable range. All animals regulate their body temperatures to a certain extent, but some animals maintain a more constant temperature than others. The maintenance of body temperature is critical for physiological and biochemical processes, many of which rely on enzymatic activity. Part A - Identifying parts of a feedback system Thermoregulation in the body is accomplished by several feedback systems. The feedback system shown here uses vasoconstriction and vasodilation in the skin and extremities to regulate body temperature. Drag the labels to their appropriate locations on the diagram of the feedback system below. Labels can be used once, more than once, or not at all. Hint 1. What are the definitions of terms used in feedback systems? Drag the terms on the left to the appropriate blanks on the right to complete the sentences. ANSWER: Hint 2. Which phrases describe the effects of vasoconstriction and vasodilation? Vasoconstriction is a decrease in the diameter of blood vessels. Vasodilation is an increase in the diameter of blood vessels. Vasoconstriction and vasodilation are responses in a thermoregulatory system. Identify some of the effects of vasoconstriction and vasodilation. Drag each phrase to the appropriate bin. ANSWER: 8/13/13 7:53 AMCh 40 HW Page 11 of 18http://session.masteringbiology.com/myct/assignmentPrintView?assignmentID=2133932 ANSWER: 8/13/13 7:53 AMCh 40 HW Page 12 of 18http://session.masteringbiology.com/myct/assignmentPrintView?assignmentID=2133932 Correct Thermoregulation relies on negative feedback. Negative feedback works to return a system to homeostasis by reducing a stimulus, such as a change in temperature. By contrast, positive feedback systems amplify or speed up a response. In thermoregulation in mammals, the stimulus is either a decreased body temperature or an elevated body temperature. If the temperature is too low, one response is vasoconstriction in the skin and extremities, resulting in lower blood flow and less heat lost to the environment through the skin. When body temperature increases to normal, homeostasis is regained. If the temperature is elevated, one of the body's responses is vasodilation in the skin and extremities. This response increases the amount of heat lost to the environment, and body temperature decreases. In mammals, the "thermostat," or temperature control system, is located in the hypothalamus. When cells in the hypothalamus detect a body temperature below the normal range, the hypothalamus will inhibit heat loss mechanisms and activate mechanisms such as shivering and vasoconstriction. When the cells detect a body temperature above the normal range, the thermostat activates heat loss mechanisms such as vasodilation, sweating, and panting. Part B - Overview of countercurrent heat exchangers The images below show two countercurrent heat exchangers in marine animals: in the flipper of a sea turtle (left) and in the abdomen of a dolphin (right). Which three of the following statements are consistent with the images? Hint 1. Countercurrent heat exchange A thermoregulatory circulatory adaptation is the countercurrent heat exchanger, which is a system of heat transfer that uses an antiparallel arrangement of arteries and veins. The warmer blood in the artery (flowing from the heart) loses its heat to the cooler blood in the vein (flowing away from body tissues to the heart). This antiparallel arrangement cools the blood in the artery and warms the blood in the vein. As a result, the blood nearer the heart is warmer than the blood in a distal tissue or structure. Countercurrent heat exchangers in animals: help maintain body heat in an environment that is cooler than body temperature help cool organs that may overheat during activity Heat loss is generally greatest in extremities such as the tail or flippers, and heat buildup can be a problem in parts of the body responsible for movement, such as the thorax of an insect or the abdominal muscles of a dolphin. Hint 2. Which way will heat flow? The diagram below represents an artery and a vein in a countercurrent exchange system. Drag arrows to the diagram to show in which direction heat will flow. The numbers represent the temperature of the blood in degrees Celsius. Drag the arrows to their appropriate locations on the diagram. Arrows can be used once, more than once, or not at all. ANSWER: 8/13/13 7:53 AMCh 40 HW Page 13 of 18http://session.masteringbiology.com/myct/assignmentPrintView?assignmentID=2133932 Hint 3. How is heat distributed in the bodies of marine animals? Knowing that there are countercurrent heat exchangers in a sea turtle's flippers and in a dolphin's abdomen, which of the following structures should be cooler than nearby body structures or tissues? Select the two that apply. ANSWER: ANSWER: sea turtle flipper sea turtle body dolphin body dolphin testes In a sea turtle's flippers, heat is transferred from (3) to (1). In a sea turtle, blood warms as it flows from the body (1) to the tip of the flipper (2). In a sea turtle's flippers, heat is transferred from (1) to (3). At a dolphin's testes, heat is transferred from (2) to (1). In a dolphin, blood cools as it flows from the aorta to the testes. At a dolphin's testes, heat is transferred from (1) to (2). 8/13/13 7:53 AMCh 40 HW Page 14 of 18http://session.masteringbiology.com/myct/assignmentPrintView?assignmentID=2133932 Correct Many marine animals, including sea turtles and dolphins, have adaptations that allow them to regulate heat gain and loss. In cooler water, the countercurrent heat exchanger in the sea turtle's flippers transfers heat from arteries to veins, resulting in heat retention in the body and cooler temperatures in the flippers. In addition to countercurrent heat exchangers in its flippers, a male dolphin's testes have a countercurrent heat exchanger to help keep them cool. The testes are surrounded by abdominal muscle that warms with activity, such as vigorous swimming. Because high temperatures can damage sperm, a countercurrent heat exchanger transfers heat from the arteries near the testes to veins carrying cooler blood from the tail. In this way, the testes are kept cool enough to protect the sperm from damage, and heat is retained in the body core. Part C - Identifying modes of thermoregulation Animals can be classified according to their mode of thermoregulation. Sort the animals below, indicating their likely thermoregulatory strategy. Note that poikilotherms are sometimes referred to as heterotherms. Drag each animal to the appropriate bin. Hint 1. What do the different terms associated with thermoregulation mean? Drag the terms on the left to the appropriate blanks on the right to complete the sentences. ANSWER: Hint 2. Can you identify a homeotherm? Homeotherms have body temperatures that remain relatively constant. Poikilotherms (heterotherms) have body temperatures that fluctuate with the temperature of the environment. In which of the following scenarios is the animal more likely to be homeothermic rather than poikilothermic (heterothermic)? Select the two that apply. ANSWER: 8/13/13 7:53 AMCh 40 HW Page 15 of 18http://session.masteringbiology.com/myct/assignmentPrintView?assignmentID=2133932 Hint 3. Thermoregulatory adaptations of different animals Different classes of animals have adaptations that suit their thermoregulatory strategy and their environment. A few examples are listed here: The arctic walrus has a large body and a thick layer of fat for insulation. Coyotes have fur for insulation. Birds have feathers for insulation. Arctic shrimp have adaptations that let their body temperatures conform to the relatively stable, but cold, ocean temperatures. Insects, such as butterflies or beetles, will sun themselves to gain heat in the morning. Some freshwater fish and amphibians will move from cooler to warmer areas to gain or maintain heat. The body temperature of an amphibian will be lower at the end of a cool night than it is after a warm day. ANSWER: a reptile basking in the sun in the desert a marine invertebrate living in the arctic where temperatures are stable an insect in an environment with fluctuating daytime temperatures a mammal in an environment with fluctuating daytime temperatures 8/13/13 7:53 AMCh 40 HW Page 16 of 18http://session.masteringbiology.com/myct/assignmentPrintView?assignmentID=2133932 Correct Animals can be described according to whether they generate their own body heat (endothermic) or gain most of their body heat from external sources (ectothermic). They can also be described according to whether they maintain a relatively constant body temperature (homeothermic) or allow their body temperature to fluctuate with the environment (poikilothermic). The diagram below illustrates that animals are not strictly endotherms, ectotherms, homeotherms, or poikilotherms but rather that there is a continuum. Although birds and mammals are generally homeothermic endotherms (upper right in the graph), there is no fixed relationship between the source of body heat and the stability of body temperature. For example, the arctic shrimp is an ectotherm; yet it is also a homeotherm due to the fact that its environment's temperature is relatively stable. Chapter 40 Pre-Test Question 9 Part A Metabolic rate is _____. Hint 1. Think of what metabolism does. ANSWER: Correct There are many variations of the measurement, such as basal metabolic rate and standard metabolic rate. directly proportional to body size the total amount of energy an animal uses in a unit of time typically higher in an ectothermic animal than in an endothermic one determined when the organism is vigorously exercising after consuming a fatty meal the amount of heat gained by an animal in a unit of time 8/13/13 7:53 AMCh 40 HW Page 17 of 18http://session.masteringbiology.com/myct/assignmentPrintView?assignmentID=2133932 Chapter 40 Pre-Test Question 10 Part A Choose the list that correctly describes metabolic rates, corrected for body mass, from lowest to highest. Hint 1. Consider how your metabolic rate compares to that of a dog, cat, and mouse. ANSWER: Correct Fish are ectotherms, typically having lower metabolic rates than endothermic mammals and birds; furthermore, a mouse is much smaller than a dog, so the mouse's cells have higher rates than those of the dog. Chapter 40 Pre-Test Question 8 Part A Bats and hummingbirds are examples of _____. Hint 1. The terms cold-blooded and warm-blooded do not easily apply to bats and hummingbirds. ANSWER: Correct Bats and hummingbirds generate warmth by metabolism, qualifying them as endotherms, but they also sometimes enter an inactive state with a variable, usually lower body temperature, qualifying them as poikilotherms. Chapter 40 Question 54 Part A dog, cat, mouse, salamander frog, rabbit, snake fish, dog, mouse hummingbird, dog, mouse gazelle, lion, elephant ectotherms that are also homeotherms endotherms that are also homeotherms endotherms that are also poikilotherms endotherms that are also ectotherms ectotherms that are also poikilotherms 8/13/13 7:53 AMCh 40 HW Page 18 of 18http://session.masteringbiology.com/myct/assignmentPrintView?assignmentID=2133932 Independent of whether an organism is an endotherm or ectoderm, the least reliable indicator of an animal's metabolic rate is the amount of ANSWER: Correct Score Summary: Your score on this assignment is 82.1%. You received 9.03 out of a possible total of 11 points. heat generated in one day. water consumed in one day. oxygen used in mitochondria in one day. food eaten in one day. carbon dioxide produced in one day. Travis Warman Ch 40 HW
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