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Chapter 20 Unifying Concepts of Animal Structure and Function PowerPoint Lectures for Campbell Biology: Concepts & Connections, Seventh Edition Reece, Taylor, Simon, and Dickey © 2012 Pearson Education, Inc. Lecture by Edward J. Zalisko Introduction How can geckos climb walls and stick to the ceiling? – The surfaces of gecko toes are covered by millions of microscopic hairs. – Each hair has a slight molecular attraction that helps it stick to the surface. – This adhesive relationship is an example of the correlation between structure and function. © 2012 Pearson Education, Inc. Figure 20.0_1 Figure 20.0_2 Chapter 20: Big Ideas Structure and Function in Animal Tissues External Exchange and Internal Regulation Organs and Organ Systems Figure 20.0_3 STRUCTURE AND FUNCTION IN ANIMAL TISSUES © 2012 Pearson Education, Inc. 20.1 Structure fits function at all levels of organization in the animal body Anatomy is the study of structure. Physiology is the study of function. Animals consist of a hierarchy of levels or organization. – Tissues are an integrated group of similar cells that perform a common function. – Organs perform a specific task and consist of two or more tissues. – Organ systems consist of multiple organs that together perform a vital body function. © 2012 Pearson Education, Inc. Figure 20.1 Cellular level Muscle cell Tissue level Muscle tissue Organ level Heart Organ system level Circulatory system Organism level Many organ systems functioning together 20.2 EVOLUTION CONNECTION: An animal’s form reflects natural selection The body plan or design of an organism – reflects the relationship between form and function, – results from natural selection, and – does not imply a process of conscious invention. Streamlined and tapered bodies – increase swimming speeds and – have similarly evolved in fish, sharks, and aquatic birds and mammals, representing convergent evolution. © 2012 Pearson Education, Inc. Video: Galápagos Sea Lion Use windows controls to play © 2012 Pearson Education, Inc. Video: Shark Eating a Seal Use windows controls to play © 2012 Pearson Education, Inc. Figure 20.2 Shark Seal Penguin 20.3 Tissues are groups of cells with a common structure and function Tissues – are an integrated group of similar cells that perform a common function and – combine to form organs. Animals have four main categories of tissues: 1. epithelial tissue, 2. connective tissue, 3. muscle tissue, and 4. nervous tissue. © 2012 Pearson Education, Inc. 20.4 Epithelial tissue covers the body and lines its organs and cavities Epithelial tissues, or epithelia, are sheets of closely packed cells that – cover body surfaces and – line internal organs and cavities. Epithelial cells come in three shapes: 1. squamous—like a fried egg, 2. cuboidal—as tall as they are wide, and 3. columnar—taller than they are wide. © 2012 Pearson Education, Inc. 20.4 Epithelial tissue covers the body and lines its organs and cavities Epithelial tissues are named according to the – number of cell layers they have and – shape of the cells on their apical surface. © 2012 Pearson Education, Inc. Figure 20.4 Apical surface of epithelium Basal lamina Underlying Cell nuclei tissue Simple squamous epithelium Pseudostratified ciliated columnar epithelium Simple cuboidal epithelium Simple columnar epithelium Stratified squamous epithelium 20.5 Connective tissue binds and supports other tissues Connective tissue can be grouped into six major types. 1. Loose connective tissue – is the most widespread, – consists of ropelike collagen and elastic fibers that are strong and resilient, and – helps to join skin to underlying tissues. 2. Fibrous connective tissue – has densely packed collagen fibers and – forms tendons that attach muscle to bone. © 2012 Pearson Education, Inc. 20.5 Connective tissue binds and supports other tissues 3. Adipose tissue stores fat in large, closely packed cells held in a matrix of fibers. 4. Cartilage – is a strong and flexible skeletal material and – commonly surrounds the ends of bones. 5. Bone – has a matrix of collagen fibers – embedded in a hard mineral substance containing calcium, magnesium, and phosphate. 6. Blood transports substances throughout the body. © 2012 Pearson Education, Inc. Figure 20.5 White blood cells Red blood cell Central canal Plasma Cell nucleus Collagen fiber Elastic fibers Matrix Blood Bone Loose connective tissue (under the skin) Cell nucleus Collagen fibers Cartilageforming cells Fat droplets Fibrous connective tissue (forming a tendon) Boneforming cells Matrix Cartilage (at the end of a bone) Adipose tissue Figure 20.5_1 Cell nucleus Collagen fiber Elastic fibers Loose connective tissue (under the skin) Figure 20.5_2 Cell nucleus Collagen fibers Fibrous connective tissue (forming a tendon) Figure 20.5_3 Fat droplets Adipose tissue Figure 20.5_4 Cartilageforming cells Matrix Cartilage (at the end of a bone) Figure 20.5_5 Central canal Matrix Bone Boneforming cells Figure 20.5_6 White blood cells Red blood cell Plasma Blood 20.6 Muscle tissue functions in movement Muscle tissue is the most abundant tissue in most animals. There are three types of vertebrate muscle tissue: 1. Skeletal muscle causes voluntary movements. 2. Cardiac muscle pumps blood. 3. Smooth muscle moves walls of internal organs, such as the intestines. © 2012 Pearson Education, Inc. Figure 20.6 Muscle fiber Unit of muscle contraction Muscle fiber (cell) Nuclei Junction between two cells Nucleus Cardiac muscle Muscle fiber Nucleus Skeletal muscle Smooth muscle Figure 20.6_1 Unit of muscle contraction Muscle fiber (cell) Nuclei Skeletal muscle Figure 20.6_2 Muscle fiber Junction between two cells Nucleus Cardiac muscle Figure 20.6_3 Muscle fiber Nucleus Smooth muscle 20.7 Nervous tissue forms a communication network Nervous tissue – senses stimuli and – rapidly transmits information. Neurons carry signals by conducting electrical impulses. Other cells in nervous tissue – insulate axons, – nourish neurons, and – regulate the fluid around neurons. © 2012 Pearson Education, Inc. Figure 20.7 Dendrites Cell body Axon ORGANS AND ORGAN SYSTEMS © 2012 Pearson Education, Inc. 20.8 Organs are made up of tissues Each tissue performs specific functions. The heart has – extensive muscle that generates contractions, – epithelial tissues that line the heart chambers, – connective tissues that make the heart elastic, and – neurons that regulate contractions. © 2012 Pearson Education, Inc. 20.8 Organs are made up of tissues The small intestine – is lined by a columnar epithelium, – includes connective tissues that contain blood vessels, and – has two layers of smooth muscle that help propel food. The inner surface of the small intestine has many fingerlike projections that increase the surface area for absorption. © 2012 Pearson Education, Inc. Figure 20.8 Small intestine Lumen Epithelial tissue (columnar epithelium) Connective tissue Smooth muscle tissue (two layers) Connective tissue Epithelial tissue 20.9 CONNECTION: Bioengineers are learning to produce tissues and organs for transplants Bioengineering is seeking ways to repair or replace damaged tissues and organs. New tissues and organs are being grown using a patient’s own cells. These techniques – remove the risk of tissue rejection and – may someday reduce the shortage of organs available for transplants. © 2012 Pearson Education, Inc. Figure 20.9 20.10 Organ systems work together to perform life’s functions Each organ system – typically consists of many organs, – has one or more functions, and – works with other organ systems to create a functional organism. © 2012 Pearson Education, Inc. Figure 20.10_L Circulatory system Respiratory system Nasal cavity Integumentary system Pharynx Hair Larynx Skin Trachea Heart Bronchus Nails Lung Blood vessels Skeletal system Bone Cartilage Urinary system Muscular system Digestive system Mouth Esophagus Skeletal muscles Liver Kidney Ureter Urinary bladder Urethra Stomach Small intestine Large intestine Anus Figure 20.10_R Endocrine system Hypothalamus Pituitary gland Thymus Thyroid gland Adrenal gland Parathyroid gland Lymphatic and immune systems Thymus Lymph nodes Spleen Appendix Bone marrow Pancreas Lymphatic vessels Testis (male) Ovary (female) Reproductive system Nervous system Brain Seminal vesicles Sense organ (ear) Spinal cord Nerves Female Male Oviduct Prostate gland Ovary Vas deferens Uterus Penis Vagina Testis Urethra 20.10 Organ systems work together to perform life’s functions The skeletal and muscular systems support and move the body. The digestive and respiratory systems obtain food and oxygen. The circulatory system transports these materials. The urinary system disposes of wastes. The integumentary system covers the body. © 2012 Pearson Education, Inc. Figure 20.10_1 Circulatory system Respiratory system Nasal cavity Heart Pharynx Larynx Trachea Bronchus Lung Blood vessels Figure 20.10_2 Integumentary system Hair Skin Nails Figure 20.10_3 Skeletal system Bone Cartilage Figure 20.10_4 Muscular system Skeletal muscles Figure 20.10_5 Urinary system Digestive system Mouth Esophagus Liver Kidney Ureter Urinary bladder Urethra Stomach Small intestine Large intestine Anus 20.10 Organ systems work together to perform life’s functions The lymphatic and immune systems protect the body from infection. The nervous and endocrine systems control and coordinate body functions. The reproductive system produces offspring. © 2012 Pearson Education, Inc. Figure 20.10_6 Endocrine system Hypothalamus Pituitary gland Thymus Thyroid gland Adrenal gland Parathyroid gland Pancreas Testis (male) Ovary (female) Figure 20.10_7 Lymphatic and immune systems Lymph nodes Thymus Spleen Appendix Bone marrow Lymphatic vessels Figure 20.10_8 Nervous system Brain Sense organ (ear) Spinal cord Nerves Figure 20.10_9 Reproductive system Seminal vesicles Female Male Oviduct Prostate gland Ovary Vas deferens Uterus Penis Vagina Testis Urethra 20.11 CONNECTION: New imaging technology reveals the inner body New technologies – are used in medical diagnosis and research and – allow physicians to examine organ systems without surgery. X-rays help create images of hard structures such as bones and teeth. Magnetic resonance imaging (MRI) – takes advantage of the behavior of the hydrogen atoms in water molecules and – provides three-dimensional images of very small structures. © 2012 Pearson Education, Inc. Figure 20.11A Femur (thigh bone) Torn meniscus Tibia (shin bone) 20.11 CONNECTION: New imaging technology reveals the inner body A newer X-ray technology called computed tomography (CT) – produces high-resolution images of cross sections of the body and – can detect small differences between normal and abnormal tissues in many organs. Positron-emission tomography (PET) helps identify metabolic processes at specific body locations. CT and PET images can be combined for an even more informative image. © 2012 Pearson Education, Inc. Figure 20.11B 20.12 The integumentary system protects the body The skin consists of two layers: 1. The epidermis – is a stratified squamous epithelium and – forms the surface of the skin. 2. The dermis – forms a deeper skin layer and – is composed of dense connective tissue with many resilient elastic fibers and strong collagen fibers. – The dermis contains hair follicles, oil and sweat glands, muscle cells, nerves, sensory receptors, and blood vessels. © 2012 Pearson Education, Inc. Figure 20.12 Hair Epidermis Sweat pore Muscle Dermis Nerve Sweat gland Hypodermis (under the skin) Adipose tissue Blood vessels Oil gland Hair follicle 20.12 The integumentary system protects the body Skin has many functions. – The epidermis – resists physical damage, – decreases water loss, and – prevents penetration by microbes. – The dermis – collects sensory information, – synthesizes vitamin D, and – helps regulate body temperature. © 2012 Pearson Education, Inc. 20.12 The integumentary system protects the body Exposure of the skin to ultraviolet light – causes skin cells to release melanin, which contributes to a visible tan, and – damages DNA of skin cells and can lead to – premature aging of the skin, – cataracts, and – skin cancers. © 2012 Pearson Education, Inc. 20.12 The integumentary system protects the body Hair – is an important component of the integumentary system of mammals, – helps to insulate their bodies, and – consists of a shaft of keratin-filled dead cells. Oil glands release oils that – are associated with hair follicles, – lubricate hair, – condition surrounding skin, and – inhibit the growth of bacteria. © 2012 Pearson Education, Inc. EXTERNAL EXCHANGE AND INTERNAL REGULATION © 2012 Pearson Education, Inc. 20.13 Structural adaptations enhance exchange with the environment Every organism is an open system that must exchange matter and energy with its surroundings. Cells in small and flat animals can exchange materials directly with the environment. © 2012 Pearson Education, Inc. 20.13 Structural adaptations enhance exchange with the environment However, as organisms increase in size, the surface area – is too small for the corresponding volume and – too far away from the deepest cells of the body. – In these organisms, evolutionary adaptations – consist of extensively branched or folded surfaces, which increase the area of these surfaces and – provide for sufficient environmental exchange. © 2012 Pearson Education, Inc. 20.13 Structural adaptations enhance exchange with the environment The respiratory system exchanges gases between the external environment and blood. The digestive system acquires food and eliminates wastes. The excretory system eliminates metabolic waste. The circulatory system – distributes gases, nutrients, and wastes throughout the body and – exchanges materials between blood and body cells through the interstitial fluid that bathes body cells. © 2012 Pearson Education, Inc. Figure 20.13A EXTERNAL ENVIRONMENT CO2 O2 Food Mouth ANIMAL Respiratory system Digestive system Interstitial fluid Heart Nutrients Circulatory system Body cells Intestine Urinary system Anus Unabsorbed matter (feces) Metabolic waste products (urine) Figure 20.13B Trachea 20.14 Animals regulate their internal environment Homeostasis is the active maintenance of a steady state within the body. – External environmental conditions may fluctuate wildly. – Homeostatic mechanisms regulate internal conditions. © 2012 Pearson Education, Inc. Figure 20.14_UN Figure 20.14 External environment Homeostatic mechanisms Large fluctuations Internal environment Small fluctuations 20.15 Homeostasis depends on negative feedback Control systems – detect change and – direct responses. Negative-feedback mechanisms – keep internal variables steady and – permit only small fluctuations around set points. © 2012 Pearson Education, Inc. Animation: Negative Feedback Right click on animation / Click play © 2012 Pearson Education, Inc. Animation: Positive Feedback Right click on animation / Click play © 2012 Pearson Education, Inc. Figure 20.15_s1 Homeostasis: Body temperature approximately 37°C Figure 20.15_s2 Brain activates cooling mechanisms. Temperature rises above set point Homeostasis: Body temperature approximately 37°C Temperature falls below set point Brain activates warming mechanisms. Figure 20.15_s3 Sweat evaporates, cooling the body. Brain activates cooling mechanisms. Blood vessels dilate. Temperature rises above set point Homeostasis: Body temperature approximately 37°C Temperature falls below set point Blood vessels constrict. Shivering generates heat. Brain activates warming mechanisms. Figure 20.15_s4 Sweat evaporates, cooling the body. Brain activates cooling mechanisms. Blood vessels dilate. Temperature decreases Cooling mechanisms shut off. Temperature rises above set point Homeostasis: Body temperature approximately 37°C Temperature increases Warming mechanisms shut off. Temperature falls below set point Blood vessels constrict. Shivering generates heat. Brain activates warming mechanisms. Figure 20.15_5 Sweat glands secrete sweat that evaporates, cooling the body. The thermostat in the brain activates cooling mechanisms. Blood vessels in the skin dilate, increasing heat loss. Temperature decreases The thermostat shuts off the cooling mechanisms. Homeostasis: Body temperature approximately 37°C Temperature rises above set point Figure 20.15_6 Homeostasis: Body temperature approximately 37°C Temperature increases The thermostat shuts off the warming mechanisms. Temperature falls below set point Blood vessels in the skin constrict, minimizing heat loss. Skeletal muscles contract; shivering generates heat. The thermostat in the brain activates warming mechanisms. You should now be able to 1. Describe the levels of organization in an animal’s body. 2. Explain how size and shape can influence the structure of an animal. 3. Define a tissue, describe the four main types of animal tissue, and note their structures and their functions. 4. Explain how the structure of organs is based on the cooperative interactions of tissues. © 2012 Pearson Education, Inc. You should now be able to 5. Explain how artificial tissues are created and used. 6. Describe the general structures and functions of the 12 major vertebrate organ systems. 7. Describe and compare X-ray, CT, MRI, and PET imaging technologies. 8. Relate the structure of the skin to its functions. © 2012 Pearson Education, Inc. You should now be able to 9. Describe the systems that help an animal exchange materials with its environment. 10. Describe examples of adaptations to increase the surface-to-volume ratio. 11. Define the concept of homeostasis and illustrate it with examples. 12. Explain how negative feedback is used to regulate internal body temperature. © 2012 Pearson Education, Inc. Function 20.5 Connective tissue binds and supports other tissues. 20.6 Muscle tissue functions in movement. 20.7 Nervous tissue forms a communication network. Sheets of closely packed cells Sparse cells in extracellular matrix Long cells (fibers) with contractile proteins Neurons with branching extensions; supporting cells Skeletal muscle Neuron Example 20.4 Epithelial tissue covers the body and lines its organs and cavities. Structure Figure 20.UN01 Columnar epithelium Loose connective tissue Function 20.5 Connective tissue binds and supports other tissues. Sheets of closely packed cells Sparse cells in extracellular matrix Example 20.4 Epithelial tissue covers the body and lines its organs and cavities. Structure Figure 20.UN01_1 Columnar epithelium Loose connective tissue 20.6 Muscle tissue functions in movement. 20.7 Nervous tissue forms a communication network. Long cells (fibers) with contractile proteins Neurons with branching extensions; supporting cells Skeletal muscle Neuron Example Structure Function Figure 20.UN01_2 Figure 20.UN02 a. b. c. d. e.