Basic Principles of Animal Form and Function within this chapter: tissue types thermoregulation metabolism

Overview: Diverse Forms, Common Challenges Anatomy is the study of the biological form of an organism Physiology is the study of the biological functions an organism performs The comparative study of animals reveals that form and function are closely correlated © 2011 Pearson Education, Inc.

how are the jackrabbit’s ears a product of the laws of physics? Figure 40.1 How does a jackrabbit keep from overheating? 3

Convergent evolution Seal Penguin Tuna Figure 40.2 Convergent evolution in fast swimmers. Penguin Tuna 4

Theme of this unit: Focus of this chapter: Life forms are machines that regulate homeostasis within a specific environment Focus of this chapter: Exchange with the environment Regulating that exchange

Concept 40.1: Animal form and function are correlated at all levels of organization Laws of physics set limits on biological morphologies. Provide and example. © 2011 Pearson Education, Inc.

Video: Shark Eating Seal © 2011 Pearson Education, Inc.

Video: Galápagos Sea Lion © 2011 Pearson Education, Inc.

Video: Hydra Eating Daphnia © 2011 Pearson Education, Inc.

Exchange with the environment A single-celled protist living in water has a sufficient surface area of plasma membrane to service its entire volume of cytoplasm VS. Multicellular organisms with a saclike body plan have body walls that are only two cells thick, facilitating diffusion of materials © 2011 Pearson Education, Inc.

Mouth Gastrovascular cavity Exchange Exchange Exchange 0.1 mm 1 mm How do complex animals exchange resources and waste with their environment? Mouth Gastrovascular cavity Exchange Exchange Exchange Figure 40.3 Contact with the environment. 0.1 mm 1 mm (a) Single cell (b) Two layers of cells 11

Internal exchange surfaces of complex animals External environment CO2 Food O2 Mouth Animal body 250 m B l o d Respiratory system Lung tissue (SEM) Heart Cells Digestive system Interstitial fluid Nutrients Circulatory system Figure 40.4 Internal exchange surfaces of complex animals. Excretory system 100 m 50 m Lining of small intestine (SEM) Blood vessels in kidney (SEM) Anus Unabsorbed matter (feces) Metabolic waste products (nitrogenous waste) 12

In vertebrates, the space between cells is filled with interstitial fluid, which allows for the movement of material into and out of cells Blood is contained within vessels © 2011 Pearson Education, Inc.

Hierarchical Organization of Body Plans Most animals are composed of specialized cells organized into tissues that have different functions Tissues make up organs, which together make up organ systems Some organs, such as the pancreas, belong to more than one organ system Benefit of complex body plans: helps an animal living in a variable environment to maintain a relatively stable internal environment © 2011 Pearson Education, Inc.

Table 40.1 Table 40.1 Organ Systems in Mammals 15

Exploring Structure and Function in Animal Tissues Tissues are classified into four main categories: Epithelial Connective Muscle Nervous © 2011 Pearson Education, Inc.

1. Epithelial Tissue Stratified squamous epithelium Pseudostratified Figure 40.5aa 1. Epithelial Tissue Stratified squamous epithelium Figure 40.5 Exploring: Structure and Function in Animal Tissues Pseudostratified columnar epithelium Cuboidal epithelium Simple columnar epithelium Simple squamous epithelium 17

Apical surface Basal surface Basal lamina 40 m Polarity of epithelia Figure 40.5ab Apical surface Basal surface Basal lamina 40 m Figure 40.5 Exploring: Structure and Function in Animal Tissues Polarity of epithelia 18

What makes gummy bears so deliciously chewy?

2. Connective Tissue Connective tissue mainly binds and supports other tissues Most diverse tissue type It contains sparsely packed cells scattered throughout an extracellular matrix The matrix consists of fibers in a liquid, jellylike, or solid foundation © 2011 Pearson Education, Inc.

There are three types of connective tissue fiber, all made of protein: Collagenous fibers provide strength and flexibility Found in: tendon, ligament, skin, cornea, cartilage, bone, blood vessels, gut, and intervertebral disc. Elastic fibers stretch and snap back to their original length Found in: extracellular matrix Reticular fibers join connective tissue to adjacent tissues Found in: liver, bone marrow, lymphatic organs © 2011 Pearson Education, Inc.

Connective tissue contains cells, including Fibroblasts that secrete the protein of extracellular fibers Macrophages that are involved in the immune system © 2011 Pearson Education, Inc.

Connective Tissue Loose connective tissue Blood…why? Cartilage Figure 40.5ba Connective Tissue Loose connective tissue Blood…why? Collagenous fiber Plasma White blood cells 120 m 55 m Elastic fiber Cartilage Red blood cells Fibrous connective tissue Chondrocytes 100 m Figure 40.5 Exploring: Structure and Function in Animal Tissues 30 m Chondroitin sulfate Nuclei Bone Adipose tissue Central canal Fat droplets 700 m 150 m Osteon 23

Cartilage is a strong and flexible support material 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 Cartilage is a strong and flexible support material Fibrous connective tissue is found in tendons, which attach muscles to bones, and ligaments, which connect bones at joints © 2011 Pearson Education, Inc.

Adipose tissue stores fat for insulation and fuel Blood is composed of blood cells and cell fragments in blood plasma Bone is mineralized and forms the skeleton © 2011 Pearson Education, Inc.

3. Muscle Tissue comes in three types: Skeletal muscle, or striated muscle, is responsible for voluntary movement Smooth muscle is responsible for involuntary body activities Cardiac muscle is responsible for contraction of the heart © 2011 Pearson Education, Inc.

Muscle Tissue Skeletal muscle Smooth muscle Cardiac muscle Nuclei Figure 40.5ca Muscle Tissue Skeletal muscle Nuclei Muscle fiber Sarcomere 100 m Smooth muscle Cardiac muscle Figure 40.5 Exploring: Structure and Function in Animal Tissues Nucleus Muscle fibers 25 m Nucleus Intercalated disk 50 m 27

4. Nervous Tissue Nervous tissue senses stimuli and transmits signals throughout the animal Nervous tissue contains Neurons, or nerve cells, that transmit nerve impulses Glial cells, or glia, that help nourish, insulate, and replenish neurons © 2011 Pearson Education, Inc.

Nervous Tissue Neurons Glia Glia Neuron: Dendrites Cell body Axons of Figure 40.5da Nervous Tissue Neurons Glia Glia 15 m Neuron: Dendrites Cell body Axons of neurons Axon Figure 40.5 Exploring: Structure and Function in Animal Tissues Blood vessel 40 m (Fluorescent LM) (Confocal LM) 29

Control and coordination within a body depend on: The Endocrine System Pros Cons The Nervous System © 2011 Pearson Education, Inc.

Figure 40.6 Figure 40.6 Signaling in the endocrine and nervous systems 31

The endocrine system The endocrine system transmits chemical signals called hormones to receptive cells throughout the body via blood A hormone may affect one or more regions throughout the body Hormones are relatively slow acting, but can have long-lasting effects

The Nervous System The nervous system transmits information between specific locations The information conveyed depends on a signal’s pathway, not the type of signal Nerve signal transmission is very fast Nerve impulses can be received by neurons, muscle cells, endocrine cells, and exocrine cells © 2011 Pearson Education, Inc.

Concept 40.2: Feedback control maintains the internal environment in many animals Animals manage their internal environment by regulating or conforming to the external environment © 2011 Pearson Education, Inc.

Regulating and Conforming A regulator uses internal control mechanisms to moderate internal change in the face of external, environmental fluctuation A conformer allows its internal condition to vary with certain external changes Animals may regulate some environmental variables while conforming to others © 2011 Pearson Education, Inc.

Figure 40.7 Figure 40.7 The relationship between body and environmental temperatures in an aquatic temperature regulator and an aquatic temperature conformer. 36

Homeostasis Organisms use homeostasis to maintain a “steady state” or internal balance regardless of external environment What is maintained at a constant level in humans? © 2011 Pearson Education, Inc.

Animation: Negative Feedback Right-click slide / select “Play” © 2011 Pearson Education, Inc.

Animation: Positive Feedback Right-click slide / select “Play” © 2011 Pearson Education, Inc.

Mechanisms of homeostasis Figure 40.8 A nonliving example of temperature regulation: control of room temperature. 40

Circadian rhythms are an example of alteration of homeostatic conditions Figure 40.9 Human circadian rhythm. 41

Homeostasis can adjust to changes in external environment, a process called acclimatization: What are some conditions to which we will acclimate? © 2011 Pearson Education, Inc.

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 tolerable range © 2011 Pearson Education, Inc.

Endothermy and Ectothermy Endothermic animals generate heat by metabolism; birds and mammals are endotherms Ectothermic animals gain heat from external sources; ectotherms include most invertebrates, fishes, amphibians, and nonavian reptiles What are the pros and cons of each? © 2011 Pearson Education, Inc.

Figure 40.10 Figure 40.10 Endothermy and ectothermy. 45

Variation in Body Temperature The body temperature of a poikilotherm varies with its environment The body temperature of a homeotherm is relatively constant The relationship between heat source and body temperature is not fixed (that is, not all poikilotherms are ectotherms) © 2011 Pearson Education, Inc.

Organisms exchange heat by four physical processes: Figure 40.11 Heat exchange between an organism and its environment. 47

Five adaptations help animals thermoregulate: Heat regulation in mammals often involves the integumentary system: skin, hair, and nails Five adaptations help animals thermoregulate: Insulation Circulatory adaptations Cooling by evaporative heat loss Behavioral responses Adjusting metabolic heat production © 2011 Pearson Education, Inc.

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 © 2011 Pearson Education, Inc.

Figure 40.12 Countercurrent heat exchangers. Countercurrent heat exchangers transfer heat between fluids flowing in opposite directions and reduce heat loss 50

Thermoregulation behaviour Figure 40.13 Thermoregulatory behavior in a dragonfly. 51

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 Some ectotherms can also shiver to increase body temperature © 2011 Pearson Education, Inc.

Burmese python Figure 40.14 Inquiry: How does a Burmese python generate heat while incubating eggs? 53

Preflight warm-up in the hawkmoth Figure 40.15 Preflight warm-up in the hawkmoth. 54

Acclimatization in Thermoregulation Birds and mammals can vary their insulation to acclimatize to seasonal temperature changes When temperatures are subzero, some ectotherms produce “antifreeze” compounds to prevent ice formation in their cells © 2011 Pearson Education, Inc.

The thermostatic function of the hypothalamus in human thermoregulation. Figure 40.16 The thermostatic function of the hypothalamus in human thermoregulation. 56

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 Energy Allocation and Use 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 © 2011 Pearson Education, Inc.

Bioenergetics of an animal: an overview. Figure 40.17 Bioenergetics of an animal: an overview. 58

Quantifying Energy Use Metabolic rate is the amount of energy an animal uses in a unit of time Metabolic rate can be determined by An animal’s heat loss The amount of oxygen consumed or carbon dioxide produced How does the average human evaluate their metabolism? Why is this potentially inaccurate? © 2011 Pearson Education, Inc.

Measuring the rate of oxygen consumption by a swimming shark. Figure 40.18 Measuring the rate of oxygen consumption by a swimming shark. 60

Minimum Metabolic Rate and Thermoregulation Basal metabolic rate (BMR) is the metabolic rate of an endotherm at rest at a “comfortable” temperature Standard metabolic rate (SMR) is the metabolic rate of an ectotherm at rest at a specific temperature Both rates assume a nongrowing, fasting, and nonstressed animal Ectotherms have much lower metabolic rates than endotherms of a comparable size © 2011 Pearson Education, Inc.

Influences on Metabolic Rate Metabolic rates are affected by many factors besides whether an animal is an endotherm or ectotherm Two of these factors are size and activity © 2011 Pearson Education, Inc.

Size and Metabolic Rate Metabolic rate is 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 © 2011 Pearson Education, Inc.

Figure 40.19 Figure 40.19 The relationship of metabolic rate to body size. 64

Energy budgets of four animals Figure 40.20 Energy budgets for four animals. 65

Torpor and Energy Conservation Torpor is a physiological state in which activity is low and metabolism decreases What would motivate an animals to go into a state of torpor? © 2011 Pearson Education, Inc.

Levels of two transcripts in an attempt to determine whether the circadian rhythm continues to run during hibernation. What conclusions can be made? Figure 40.21 Inquiry: What happens to the circadian clock during hibernation? 67

Long-term torpor is called hibernation Summer torpor, called estivation, enables animals to survive long periods of high temperatures and scarce water Daily torpor is exhibited by many small mammals and birds and seems adapted to feeding patterns © 2011 Pearson Education, Inc.

Review Figure 40.UN01 Summary figure, Concept 40.2 69

Testing your understanding of the big picture Draw a model of the control circuit(s) required for driving an automobile at a fairly constant speed over a hilly road, or for a human controlling temperature within their body. Indicate each feature that represents a sensor, stimulus, or response.

Figure 40.UN02 Figure 40.UN02 Appendix A: answer to Test Your Understanding, question 8 71