Chapter 40 The Animal Body.pdf

Chapter 40 The Animal Body © 2021 Pearson Education Ltd. Lecture Presentations by Nicole Tunbridge and Kathleen Fitzpatrick Figure 40.1a Emperor penguins (Aptenodytes forsteri) live in Antarctica, Earth’s coldest and windiest continent. In summer, these birds catch fish by diving down 500 meters...

Chapter 40 The Animal Body © 2021 Pearson Education Ltd. Lecture Presentations by Nicole Tunbridge and Kathleen Fitzpatrick Figure 40.1a Emperor penguins (Aptenodytes forsteri) live in Antarctica, Earth’s coldest and windiest continent. In summer, these birds catch fish by diving down 500 meters in water only 2oC above freezing. In winter, the females forage and the males incubate eggs while temperatures drop to –40oC and winds gust to 200 km/hr. © 2021 Pearson Education Ltd. Figure 40.1b How do animals regulate their internal state even in changing or harsh environments? © 2021 Pearson Education Ltd. CONCEPT 40.1: Animal form(형태) and function(기능) are correlated at all levels of organization • All animals must obtain nutrients and oxygen, fight off infection, and survive to produce offspring. • Animals’ form including anatomy—biological structure— varies widely. • Because structure and function are correlated, examining anatomy often provides clues to physiology—biological function. • Size and shape affect the way an animal interacts with its environment. • The body plan of an animal is programmed by the genome itself the product of millions of years of evolution. © 2021 Pearson Education Ltd. Evolution of Animal Size and Shape • Physical laws that govern strength, diffusion, movement, and heat exchange limit the range of animal forms. • Properties of water limit possible shapes for fast swimming animals. • Convergent evolution (수렴 진화) often results in similar adaptations of diverse organisms facing the same challenge. © 2021 Pearson Education Ltd. • As animals increase in size, thicker skeletons are required for support. • Muscles required for locomotion represent a larger fraction of the total body mass. • At some point, mobility becomes limited. © 2021 Pearson Education Ltd. Exchange (교환) with the Environment • Materials such as nutrients, waste products, and gases must be exchanged across the plasma membranes of animal cells. • Rate of exchange is proportional to a cell’s surface area, while amount of material that must be exchanged is proportional to a cell’s volume. • A single-celled organism living in water has sufficient surface area to carry out all necessary exchange. • A multicellular organization only works if every cell has access to a suitable aqueous environment. © 2021 Pearson Education Ltd. • Multicellular organisms with a saclike body plan have body walls that are only two cells thick, facilitating diffusion of materials. • In flat animals such as tapeworms, most cells are in direct contact with their environment. Figure 40.3 Direct exchange with the environment © 2021 Pearson Education Ltd. • More complex organisms are composed of compact masses of cells with a more complex internal organization. • Evolutionary adaptations such as specialized, extensively branched or folded structures enable sufficient exchange with the environment. Figure 40.4 Internal exchange surfaces of complex animals • In animals, the space between cells is filled with interstitial fluid (간질용액), which links exchange surfaces to body cells. • A complex body plan helps an animal living in a variable environment to maintain a relatively stable internal environment. © 2021 Pearson Education Ltd. Hierarchical Organization of Body Plans • Most animals are composed of cells (세포) organized into tissues (조직), groups of cells with a similar appearance and a common function. • Tissues make up organs (기관), which together make up organ systems (기관계). • Some organs, such as the pancreas, belong to more than one organ system. © 2021 Pearson Education Ltd. Table 40.1 Organ Systems in Mammals 소화계 순환계 호흡계 면역계 배설계 내분비계 생식계 신경계 외피계 골격계 근육계 © 2021 Pearson Education Ltd. • There are four main types of animal tissues: – Epithelial – Connective – Muscle – Nervous © 2021 Pearson Education Ltd. Figure 40.5 Exploring structure and function in animal tissues Epithelial Tissue (상피 조직) • Epithelial tissue covers the outside of the body and lines the organs and cavities within the body • It contains cells that are closely packed • The shape of epithelial cells may be cuboidal (like dice), columnar (like bricks on end), or squamous (like floor tiles) © 2021 Pearson Education Ltd. Figure 40.5a Exploring structure and function in animal tissues: Epithelial Tissue © 2021 Pearson Education Ltd. Connective Tissue (결합 조직) • Connective tissue holds many tissues and organs together and in place. • It contains sparsely packed cells scattered throughout an extracellular matrix. • The matrix consists of fibers in a liquid, jellylike, or solid foundation. © 2021 Pearson Education Ltd. • Connective tissue contains cells, including – Fibroblasts (섬유아세포), which secrete fiber proteins. – Macrophages (대식세포), which engulf foreign particles and cell debris by phagocytosis. • There are three types of connective tissue fiber, all made of protein: – Collagenous fibers provide strength and flexibility – Reticular fibers join connective tissue to adjacent tissues – Elastic fibers stretch and snap back to their original length © 2021 Pearson Education Ltd. • In vertebrates, the fibers and foundation combine to form six major types of connective tissue: – Loose connective tissue binds epithelia to underlying tissues and holds organs in place. – Bone is mineralized and forms the skeleton. – Fibrous connective tissue is found in tendons (힘줄, 건), which attach muscles to bones, and ligaments (인대), which connect bones at joints. – Adipose tissue stores fat for insulation and fuel. – Blood is composed of blood cells and cell fragments in blood plasma. – Cartilage (연골) is a strong and flexible support material: collagen fibers. © 2021 Pearson Education Ltd. Figure 40.5b Exploring structure and function in animal tissues: Connective Tissue © 2021 Pearson Education Ltd. Muscle Tissue • Muscle tissue is responsible for nearly all types of body movement. • Muscle cells consist of filaments of the proteins actin and myosin, which together enable muscles to contract. • Muscle tissue in the vertebrate body is divided into three types: – Skeletal muscle (골격근), or striated muscle, is responsible for voluntary movement. – Smooth muscle (평활근) is responsible for involuntary body activities. – Cardiac muscle (심장근) is responsible for contraction of the heart. © 2021 Pearson Education Ltd. Figure 40.5c Exploring structure and function in animal tissues: Muscle Tissue © 2021 Pearson Education Ltd. Video: Cardiac Muscle Contraction © 2021 Pearson Education Ltd. Nervous Tissue • Nervous tissue functions in the receipt, processing, and transmission of information. • Nervous tissue contains – Neurons(신경세포), or nerve cells, which transmit nerve impulses – Glial cells, or glia(신경아교세포), which support cells. © 2021 Pearson Education Ltd. Coordination (통합) and Control (조절) • Animals have two major systems for coordinating and controlling responses to stimuli: the endocrine and the nervous systems. • The endocrine system releases signaling molecules that are carried to all locations in the body. • The nervous system transmits information along dedicated routes, connecting specific locations in the body. • The signaling molecules broadcast through the body by the endocrine system are called hormones. • A hormone may remain in the bloodstream for minutes or even hours. • Different hormones cause distinct effects and may affect a single location or sites throughout the body. © 2021 Pearson Education Ltd. Figure 40.6 Signaling in the endocrine and nervous systems • The endocrine system is well adapted for coordinating gradual changes that affect the entire body. • The nervous system is suited for directing immediate and rapid responses to the environment. • The endocrine and nervous systems often work in close coordination; both help maintain a stable internal environment. © 2021 Pearson Education Ltd. CONCEPT 40.2: Feedback control maintains the internal environment in many animals Regulating and Conforming • An animal that is a regulator (조절자) uses internal control mechanisms to control internal change in the face of external fluctuation. • A conformer (순응자) allows its internal condition to vary with certain external changes. • Animals may regulate some environmental variables while conforming to others. © 2021 Pearson Education Ltd. Figure 40.7 The relationship between body and environmental temperatures in an aquatic temperature regulator and an aquatic temperature conformer © 2021 Pearson Education Ltd. Homeostasis (항상성) • Organisms use homeostasis to maintain a “steady state”— a relatively constant internal environment—regardless of external environment. • In humans, body temperature, blood pH, and glucose concentration are each maintained at a fairly constant level. © 2021 Pearson Education Ltd. Mechanisms of Homeostasis • The homeostatic control system in animals maintains a variable at or near a particular value, or set point. • A fluctuation above or below the set point serves as a stimulus, which is detected by a sensor. • A control center then generates output that triggers a response. • The response helps return the variable to the set point © 2021 Pearson Education Ltd. Figure 40.8 A nonliving example of temperature regulation: control of room temperature Feedback Control in Homeostasis • Negative feedback (음성되먹임) is a control mechanism that “damps (감쇠시키다)” a stimulus. • It plays a major role in homeostasis in animals. • Homeostasis moderates but doesn’t eliminate changes in the internal environment. • Positive feedback (양성되먹임) amplifies a stimulus and does not play a major role in homeostasis. Instead, it helps drive a process (such as childbirth) to completion. © 2021 Pearson Education Ltd. Alterations in Homeostasis • Set points and normal ranges can change with age or show cyclic variation. • In animals and plants, a circadian rhythm (생체리듬) governs physiological changes that occur roughly every 24 hours. Figure 40.9 Human circadian rhythm © 2021 Pearson Education Ltd. • Homeostasis is sometimes altered by acclimatization (순화). • This is a change in an animal’s physiology as it adjusts to changes in its external environment. • An example is adaptation to changes in altitude. Figure 40.10 Acclimitization by mountain climbers in the Himalayas © 2021 Pearson Education Ltd. CONCEPT 40.3: Homeostatic processes for thermoregulation involve form, function, and behavior • Thermoregulation is the process by which animals maintain an internal temperature within a normal range. Endothermy and Ectothermy • Endothermic animals (내온 동물) generate heat by metabolism; birds and mammals are endotherms. • Ectothermic animals (외온 동물) gain heat from external sources; ectotherms include fishes, amphibians, nonavian reptiles, and most invertebrates. © 2021 Pearson Education Ltd. • Endothermy is more energetically expensive than ectothermy; ectotherms need to consume less food than equally sized endotherms. • In general, ectotherms tolerate greater variation in internal temperature. © 2021 Pearson Education Ltd. Figure 40.11 Thermoregulation by internal or external sources of heat Variation in Body Temperature • The body temperature of a poikilotherm (변온동물) varies with its environment. • The body temperature of a homeotherm (항온동물) is relatively constant. • The relationship between heat source and body temperature is not fixed (that is, not all poikilotherms are ectotherms). © 2021 Pearson Education Ltd. Balancing Heat Loss and Gain • Organisms exchange heat by four physical processes: – Radiation (복사) – Evaporation (증발) – Convection (대류) – Conduction (전도) Figure 40.12 Heat exchange between an organism and its environment © 2021 Pearson Education Ltd. • Heat regulation in mammals often involves the integumentary system (외피계): skin, hair, and nails • Five adaptations help animals’ thermoregulation: – Insulation – Circulatory adaptations – Cooling by evaporative heat loss – Behavioral responses – Adjusting metabolic heat production © 2021 Pearson Education Ltd. Insulation (단열) • Insulation is a major thermoregulatory adaptation in mammals and birds. • It reduces the flow of heat between an animal’s body and its environment. • Skin, feathers, fur, and blubber (해수유, 고래지방층) reduce heat flow between an animal and its environment. • Insulation is especially important in marine mammals such as whales and walruses. © 2021 Pearson Education Ltd. Circulatory Adaptations • Regulation of blood flow near the body surface significantly affects thermoregulation. • Many endotherms and some ectotherms can alter the amount of blood flowing between the body core and the skin. • In vasodilation, blood flow in the skin increases, facilitating heat loss. • In vasoconstriction, blood flow in the skin decreases, lowering heat loss. © 2021 Pearson Education Ltd. • The arrangement of blood vessels in many marine mammals and birds allows for countercurrent heat exchange (역류열교환). • Countercurrent heat exchangers transfer heat between fluids flowing in opposite directions and thereby reduce heat loss. Figure 40.13 Countercurrent heat exchangers • Certain sharks, fishes, and insects also use countercurrent heat exchanges. • Many endothermic insects have countercurrent heat exchangers that help maintain a high temperature in the thorax. © 2021 Pearson Education Ltd. Cooling by Evaporative Heat Loss • Many mammals and birds live in places where regulating the body temperature requires cooling in addition to warming the body. • When the environmental temperature is above that of the body, evaporation can keep the body temperature from rising. • Sweating or bathing moistens the skin, helping to cool an animal down. • Panting increases the cooling effect in birds and many mammals. © 2021 Pearson Education Ltd. Behavioral Responses • Ectotherms, and sometimes endoderms, use behavioral responses to control body temperature. • They may seek warm places when cold and orient themselves toward heat sources. • When hot, they bathe, move to cooler areas, or change orientation to minimize heat absorption. Figure 40.14 Thermoregulatory behavior of a dragonfly © 2021 Pearson Education Ltd. • Social behavior contributes to thermoregulation in both endotherms and ectotherms. • Endotherms such as Emperor penguins may huddle together to conserve heat. • Individuals move between the cooler outer edges of the huddle and the warmer center. • In hot weather, honeybees transport water to the hive and fan with their wings, promoting evaporation and convection. © 2021 Pearson Education Ltd. Adjusting Metabolic Heat Production • Thermogenesis is the adjustment of metabolic heat production to maintain body temperature. • Thermogenesis is increased by muscle activity such as moving or shivering. • Nonshivering thermogenesis takes place when hormones cause mitochondria to increase their metabolic activity. Figure 40.15 Brown fat activity during cold stress. © 2021 Pearson Education Ltd. • Some mammals have a tissue called brown fat that is specialized for rapid heat production. • Extra mitochondria in brown fat produce its characteristic color. • It is found in the infants of many mammals and in adult mammals that hibernate. • The amount of brown fat in human adults has been found to vary depending on the temperature of the surrounding environment. • Birds and some nonavian reptiles can also raise body temperature through shivering. © 2021 Pearson Education Ltd. Figure 40.16 Inquiry: How does a Burmese python generate heat while incubating eggs? © 2021 Pearson Education Ltd. Acclimatization (순화) in Thermoregulation • Birds and mammals can adjust their insulation to acclimatize to seasonal temperature changes. • Lipid composition of cell membranes may change with temperature. • When temperatures are subzero, some ectotherms produce “antifreeze” compounds to prevent ice formation in their cells. © 2021 Pearson Education Ltd. Physiological Thermostats and Fever • In mammals, the sensors responsible for thermoregulation are concentrated in a region of the brain called the hypothalamus (시상하부). • The hypothalamus triggers heat loss or heat-generating mechanisms. • Fever, a response to some infections, reflects an increase in the normal range for the biological thermostat. • Some ectothermic organisms seek warmer environments to increase their body temperature in response to certain infections. © 2021 Pearson Education Ltd. Figure 40.17 The thermostatic function of the hypothalamus in human thermoregulation Thermostat (자동온도조절장치) © 2021 Pearson Education Ltd. CONCEPT 40.4: Energy requirements are related to animal size, activity, and environment • Bioenergetics is the overall flow and transformation of energy in an animal. • It determines an animal’s nutritional needs, and it relates to an animal’s size, activity, and environment. © 2021 Pearson Education Ltd. Energy Allocation and Use • Organisms can be classified by how they obtain chemical energy. • Autotrophs (자가영양생명체), such as plants, harness light energy to build energy-rich molecules. • Heterotrophs (종속영양생명체), such as animals, harvest chemical energy from food. • Energy-containing molecules from food are usually used to make ATP, which powers cellular work. • After the needs of staying alive are met, remaining food molecules can be used in biosynthesis. • Biosynthesis includes body growth and repair, synthesis of storage material such as fat, and production of gametes. © 2021 Pearson Education Ltd. Figure 40.18 Bioenergetics of an animal: an overview © 2021 Pearson Education Ltd. Quantifying Energy Use • Metabolic rate (물질대사율) is the sum of all the energy an animal uses in a unit of time. • Metabolic rate can be determined by – An animal’s heat loss (calorimeter) – The amount of oxygen consumed or carbon dioxide produced – Measuring energy content of food consumed and energy lost in waste products © 2021 Pearson Education Ltd. Figure 40.19 Measuring the rate of oxygen consumption by a swimming shark © 2021 Pearson Education Ltd. Minimum Metabolic Rate and Thermoregulation • Basal metabolic rate (BMR, 기초대사율) is the metabolic rate of an endotherm at rest, with an empty stomach, and not experiencing stress. • BMR is measured under a comfortable temperature range. • Standard metabolic rate (SMR, 표준대사율) is the metabolic rate of a fasting, non-stressed ectotherm at rest at a specific temperature. • Ectotherms have much lower metabolic rates than endotherms of a comparable size. © 2021 Pearson Education Ltd. Influences on Metabolic Rate • Metabolic rates are affected by many factors besides whether an animal is an endotherm or ectotherm. • Some key factors are age, sex, size, activity, temperature, and nutrition. Figure 40.20 The relationship of metabolic rate to body size © 2021 Pearson Education Ltd. Size and Metabolic Rate • Metabolic rate is roughly proportional to body mass to the power of three-quarters (m3/4). • Smaller animals have higher metabolic rates per gram than larger animals. • The higher metabolic rate of smaller animals leads to a higher oxygen delivery rate, breathing rate, heart rate, and greater (relative) blood volume, compared with a larger animal. • Trade-offs (교환) shape the evolution of body plans: As body size increases, energy costs per gram of tissue decrease but a larger fraction of body tissue is needed for exchange, support, and locomotion. © 2021 Pearson Education Ltd. Activity and Metabolic Rate • Activity greatly affects metabolic rate for both endotherms and ectotherms. • In general, the maximum metabolic rate an animal can sustain is inversely related to the duration of the activity. • For most terrestrial animals (육상동물), the average daily rate of energy consumption is two to four times BMR (endotherms) or SMR (ectotherms). • The fraction of an animal’s energy budget devoted to activity depends on factors such as environment, behavior, size, and thermoregulation. © 2021 Pearson Education Ltd. Torpor and Energy Conservation • Torpor (휴면) is a physiological state of decreased activity and metabolism. • Torpor enables animals to save energy while avoiding difficult and dangerous conditions. • Daily torpor is exhibited by many small mammals and birds and seems adapted to feeding patterns. • Hibernation (동면) is long-term torpor that is an adaptation to winter cold and food scarcity. Figure 40.21 A hazel dormouse (Muscardinus avellanarius) hibernating © 2021 Pearson Education Ltd. • Metabolic rates during hibernation can be 20 times lower than if the animal attempted to maintain normal body temperature (36– 38ºC). • Summer torpor, called estivation (하면), enables animals to survive long periods of high temperatures and scarce water. • In the European hamster, the molecular components of the circadian clock cease operation during hibernation. Figure 40.22 Inquiry: What happens to the circadian clock during hibernation? © 2021 Pearson Education Ltd. © 2021 Pearson Education Ltd. Figure 40.UN01 Skills exercise: interpreting pie charts © 2021 Pearson Education Ltd.