Chapter 20 Unifying Concepts of Animal Structure and Function PowerPoint Lectures for Campbell Biology: Concepts & Connections, Seventh Edition Reece, Taylor, Simon, and Dickey 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.
Figure 20.0_2 Chapter 20: Big Ideas Structure and Function in Animal Tissues Organs and Organ Systems External Exchange and Internal Regulation
Figure 20.0_3
STRUCTURE AND FUNCTION IN ANIMAL TISSUES
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.
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. Video: Galápagos Sea Lion Video: Shark Eating a Seal
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.
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.
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.
Figure 20.4 Basal lamina Apical surface of epithelium Underlying tissue Cell nuclei 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.
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.
Figure 20.5 White blood cells Cell nucleus Collagen fiber Elastic fibers Loose connective tissue (under the skin) Cell nucleus Collagen fibers Fat droplets Fibrous connective tissue (forming a tendon) Blood Adipose tissue Red blood cell Plasma Bone Cartilage (at the end of a bone) Central canal Matrix Boneforming cells Cartilageforming cells Matrix
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.
Figure 20.6 Unit of muscle contraction Muscle fiber (cell) Nucleus Muscle fiber Junction between two cells Nuclei Cardiac muscle Muscle fiber Nucleus Skeletal muscle 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.
Figure 20.7 Dendrites Cell body Axon
ORGANS AND ORGAN SYSTEMS
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.
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.
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.
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.
Figure 20.10_L Heart Blood vessels Circulatory system Nasal cavity Respiratory system Pharynx Larynx Trachea Bronchus Lung Skeletal system Integumentary system Hair Skin Nails Bone Cartilage Muscular system Urinary system Digestive system Mouth Skeletal muscles Kidney Esophagus Liver Stomach Ureter Urinary bladder Small intestine Large intestine Urethra Anus
Figure 20.10_R Endocrine system Hypothalamus Lymphatic and immune systems Thymus Adrenal gland Pituitary gland Thyroid gland Parathyroid gland Lymph nodes Appendix Thymus Spleen Pancreas Testis (male) Ovary (female) Bone marrow Lymphatic vessels Reproductive system Nervous system Brain Sense organ (ear) Spinal cord Nerves Oviduct Ovary Female Male Seminal vesicles Prostate gland Vas deferens Uterus Vagina Testis Penis 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.
Figure 20.10_1 Heart Blood vessels Circulatory system Nasal cavity Respiratory system Pharynx Larynx Trachea Bronchus Lung
Figure 20.10_4 Muscular system Skeletal muscles
Figure 20.10_5 Urinary bladder Kidney Ureter Urethra Urinary system Digestive system Mouth Esophagus Liver 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.
Figure 20.10_6 Endocrine system Hypothalamus Pituitary gland Thymus Adrenal gland Thyroid 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 Oviduct Female Male Seminal vesicles Prostate gland Ovary Vas deferens Uterus Vagina Testis Penis 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.
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.
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.
Figure 20.12 Hair Epidermis Dermis Hypodermis (under the skin) Adipose tissue Sweat pore Muscle Nerve Sweat gland 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.
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.
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.
EXTERNAL EXCHANGE AND INTERNAL REGULATION
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.
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.
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.
Figure 20.13A EXTERNAL ENVIRONMENT Mouth Food CO 2 O2 ANIMAL Digestive system Respiratory system Heart Interstitial fluid Nutrients Circulatory system Body cells Intestine Urinary system Anus Unabsorbed matter (feces) Metabolic waste products (urine)
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.
Figure 20.14 External environment Large fluctuations Homeostatic mechanisms 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. Animation: Negative Feedback Animation: Positive Feedback
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. Temperature decreases Cooling mechanisms shut off. Blood vessels dilate. 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. Temperature decreases Blood vessels in the skin dilate, increasing heat loss. The thermostat shuts off the cooling mechanisms. Temperature rises above set point Homeostasis: Body temperature approximately 37 C
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.
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.
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.
Figure 20.UN01 Example Structure Function 20.4 Epithelial tissue covers the body and lines its organs and cavities. Sheets of closely packed cells 20.5 Connective tissue binds and supports other tissues. Sparse cells in extracellular matrix 20.6 Muscle tissue functions in movement. Long cells (fibers) with contractile proteins 20.7 Nervous tissue forms a communication network. Neurons with branching extensions; supporting cells Columnar epithelium Loose connective tissue Skeletal muscle Neuron
Figure 20.UN01_1 Example Structure Function 20.4 Epithelial tissue covers the body and lines its organs and cavities. Sheets of closely packed cells Columnar epithelium 20.5 Connective tissue binds and supports other tissues. Sparse cells in extracellular matrix Loose connective tissue
Figure 20.UN01_2 Example Structure Function 20.6 Muscle tissue functions in movement. Long cells (fibers) with contractile proteins Skeletal muscle 20.7 Nervous tissue forms a communication network. Neurons with branching extensions; supporting cells Neuron
Figure 20.UN02 a. b. c. d. e.