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Chapter 21 Unifying Concepts of Animal Structure and Function PowerPoint® Lectures created by Edward J. Zalisko for Campbell Essential Biology, Sixth Edition, and Campbell Essential Biology with Physiology, Fifth Edition – Eric J. Simon, Jean L. Dickey, Kelly A. Hogan, and Jane B. Reece © 2016 Pearson Education, Inc. Figure 21.0-1 Why Animal Structure and Function Matter © 2016 Pearson Education, Inc. The Structural Organization of Animals • Life is characterized by a hierarchy of organization. • In animals, • individual cells are grouped into tissues, • tissues combine to form organs, • organs are organized into organ systems, and • organ systems make up the entire organism. © 2016 Pearson Education, Inc. Figure 21.1-s1 Cellular level: Muscle cell Tissue level: Cardiac muscle © 2016 Pearson Education, Inc. Figure 21.1-s2 Cellular level: Muscle cell Tissue level: Cardiac muscle Organ level: Heart Organ system level: Circulatory system © 2016 Pearson Education, Inc. Figure 21.1-s3 Cellular level: Muscle cell Tissue level: Cardiac muscle Organ level: Heart Organ system level: Circulatory system © 2016 Pearson Education, Inc. Organism level: Multiple organ systems functioning together Structure/Function: Anatomy and Physiology • Biologists distinguish anatomy from physiology. • Anatomy is the study of the structure of an organism’s parts. • Physiology is the study of the function of those parts. • The correlation of structure and function is a fundamental principle of biology that is evident at all levels of life’s hierarchy. © 2016 Pearson Education, Inc. Figure 21.2-s1 (a) At the organism level © 2016 Pearson Education, Inc. Figure 21.2-s2 (b) At the organ level (a) At the organism level © 2016 Pearson Education, Inc. Figure 21.2-s3 (b) At the organ level (a) At the organism level (c) At the cellular level © 2016 Pearson Education, Inc. Figure 21.2-1 © 2016 Pearson Education, Inc. Tissues • The cell is the basic unit of all living organisms. • In almost all animals, including humans, cells are grouped into tissues. • A tissue is an integrated group of similar cells that performs a specific function. • Animals have four main categories of tissue: 1. epithelial tissue, 2. connective tissue, 3. muscle tissue, and 4. nervous tissue. © 2016 Pearson Education, Inc. Epithelial Tissue • Epithelial tissue, also known as epithelium, • covers the surface of the body and • lines organs. © 2016 Pearson Education, Inc. Figure 21.3 Examples of organs lined with epithelial tissue Heart Lung Stomach Small intestine Large intestine Urinary bladder Epithelial Epithelial tissue covering body (skin) cells Spaces for exchange © 2016 Pearson Education, Inc. Epithelial tissue lining capillaries Epithelial Tissue • The body continuously renews the cells of many epithelial tissues. • Such turnover requires cells to divide rapidly, which increases the risk of an error in cell division, a mistake that can lead to cancer. © 2016 Pearson Education, Inc. Connective Tissue • Connective tissue contains cells scattered throughout a material called the extracellular matrix. • The structure of the matrix varies and matches the function of each tissue. • Two major functions of the connective tissue are to support and join other tissues. © 2016 Pearson Education, Inc. Figure 21.4 Loose connective tissue Adipose tissue Blood Fibrous connective tissue Bone © 2016 Pearson Education, Inc. Cartilage Figure 21.4-1 Cell Collagen fiber Loose connective tissue (under the skin) © 2016 Pearson Education, Inc. Figure 21.4-2 Fat droplets Adipose tissue © 2016 Pearson Education, Inc. Figure 21.4-3 White blood cells Red blood cell Plasma Blood © 2016 Pearson Education, Inc. Figure 21.4-4 Cell nucleus Collagen fibers Fibrous connective tissue (forming a tendon) © 2016 Pearson Education, Inc. Figure 21.4-5 Cells Matrix Cartilage (at the end of a bone) © 2016 Pearson Education, Inc. Figure 21.4-6 Matrix Cells Bone © 2016 Pearson Education, Inc. Connective Tissue • Figure 21.4 illustrates six of the major types of connective tissue. 1. Loose connective tissue • is the most widespread connective tissue in the body of vertebrates and • binds epithelia to underlying tissues. © 2016 Pearson Education, Inc. Connective Tissue 2. Fibrous connective tissue has a dense matrix of collagen. It forms • tendons, which attach muscles to bones, and • ligaments, which strongly join bones together at joints. © 2016 Pearson Education, Inc. Connective Tissue 3. Cartilage • is strong but flexible, • has no blood vessels, so it heals very slowly, and • functions as a flexible, boneless skeleton. © 2016 Pearson Education, Inc. Connective Tissue 4. Bone • is a rigid connective tissue with a matrix of collagen fibers hardened with deposits of calcium salts. • This combination makes bone hard without being brittle. © 2016 Pearson Education, Inc. Connective Tissue 5. Adipose tissue • stores fat in closely packed cells of a sparse matrix, • functions as an energy bank, and • insulates and cushions the body. © 2016 Pearson Education, Inc. Connective Tissue 6. Blood • consists of cells suspended in a liquid matrix called plasma and • transports substances in the plasma from one part of the body to another, • plays major roles in immunity, and • seals broken blood vessels. © 2016 Pearson Education, Inc. Muscle Tissue • Muscle tissue • is the most abundant tissue in most animals, • consists of bundles of long, thin, cylindrical cells called muscle fibers, and • has specialized proteins arranged into a structure that contracts when stimulated by a signal from a nerve. © 2016 Pearson Education, Inc. Figure 21.5 Skeletal muscle Cardiac muscle Smooth muscle © 2016 Pearson Education, Inc. Figure 21.5-1 Unit of muscle contraction Muscle fiber (cell) Nuclei Skeletal muscle (short segments of several muscle fibers) © 2016 Pearson Education, Inc. Figure 21.5-2 Junction between two cells Muscle fiber Nucleus Cardiac muscle © 2016 Pearson Education, Inc. Figure 21.5-3 Muscle fiber Nucleus Smooth muscle © 2016 Pearson Education, Inc. Muscle Tissue • Skeletal muscle • is attached to bones by tendons, • moves your skeleton, and • is responsible for voluntary movements. © 2016 Pearson Education, Inc. Muscle Tissue • Cardiac muscle is found only in heart tissue. The contraction of the cardiac muscle produces a coordinated heartbeat. © 2016 Pearson Education, Inc. Muscle Tissue • Smooth muscle is found in many organs and can contract slowly for a long period of time. • The powerful contractions of smooth muscle expel the fetus from the uterus during childbirth. • The walls of the intestines are composed of smooth muscle that contracts to move food and waste along. • Smooth muscle is also found in blood vessels. Rings of smooth muscle in blood vessels widen, causing blood to quickly flow to your face and neck. © 2016 Pearson Education, Inc. Nervous Tissue • Nervous tissue • makes communication of information possible, • is found in your brain and spinal cord, and • consists of a network of neurons. • The basic unit of nervous tissue is the neuron, or nerve cell. © 2016 Pearson Education, Inc. Figure 21.6 Brain Signal-receiving extensions Cell body Nerve LM Signaltransmitting extension © 2016 Pearson Education, Inc. Spinal cord Figure 21.6-1 Signal-receiving Cell body extensions LM Signaltransmitting extension © 2016 Pearson Education, Inc. Interconnections within Systems: Organs and Organ Systems • An organ consists of two or more tissues packaged into one working unit that performs a specific function. • An organ performs functions that none of its component tissues can carry out alone. • Examples include the heart, brain, and small intestines. • To see how multiple tissues interconnect in a single organ, examine the layered arrangement of tissues in the wall of the small intestine in Figure 21.7. © 2016 Pearson Education, Inc. Figure 21.7 Small intestine (cut open) Epithelial tissue Connective tissue (containing blood and lymph vessels) Smooth muscle tissue (two layers) Connective tissue © 2016 Pearson Education, Inc. Epithelial tissue Interconnections within Systems: Organs and Organ Systems • Organ systems are teams of organs that • work together and • perform vital body functions. © 2016 Pearson Education, Inc. Figure 21.8-1 Metacarpals Carpals Radius Ulna Humerus Shoulder Clavicle girdle Scapula Phalanges Skull Bone Sternum Ribs Vertebra Cartilage Pelvic girdle Skeletal system: supports body and anchors muscles Femur Patella Tibia Fibula Tarsals Metatarsals Phalanges © 2016 Pearson Education, Inc. Figure 21.8-2 Circulatory system: transports substances throughout body Heart Blood vessels © 2016 Pearson Education, Inc. Figure 21.8-3 Nasal cavity Pharynx Respiratory system: exchanges O2 and CO2 between blood and air Larynx Trachea Bronchus Lung © 2016 Pearson Education, Inc. Figure 21.8-4 Muscular system: moves the body Skeletal muscles © 2016 Pearson Education, Inc. Figure 21.8-5 Digestive system: breaks down food and absorbs nutrients Mouth Esophagus Liver Stomach Large intestine Small intestine Anus © 2016 Pearson Education, Inc. Figure 21.8-6 Urinary system: rids body of certain wastes Kidney Ureter Urinary bladder Urethra © 2016 Pearson Education, Inc. Figure 21.8-7 Endocrine system: secretes hormones that regulate body Hypothalamus Pituitary gland Parathyroid gland Thyroid gland Adrenal gland Pancreas Testis (male) © 2016 Pearson Education, Inc. Ovary (female) Figure 21.8-8 Reproductive system: produces gametes and offspring Seminal vesicles Prostate gland Oviduct Vas deferens Ovary Uterus Vagina Penis Urethra Testis © 2016 Pearson Education, Inc. Figure 21.8-9 Integumentary system: protects body Hair Skin Nail © 2016 Pearson Education, Inc. Figure 21.8-10 Lymphatic and immune system: defends against disease Tonsil Thymus Spleen Appendix Lymph nodes Lymphatic vessels © 2016 Pearson Education, Inc. Figure 21.8-11 Nervous system: processes sensory information and controls responses Brain Sense organ (ear) Spinal cord Nerves © 2016 Pearson Education, Inc. Interconnections within Systems: Organs and Organ Systems • An organism depends on the interconnection of all its organ systems for survival. • Your body is a whole, living unit that is greater than the sum of its parts. © 2016 Pearson Education, Inc. Exchanges with the External Environment • Every organism is an open system that continuously exchanges chemicals and energy with its surroundings. • An animal’s size and shape affect its exchanges with its surrounding environment. • Every living cell of an animal’s body must be bathed in a watery solution, partly because substances must be dissolved in water to cross cell membranes. © 2016 Pearson Education, Inc. Exchanges with the External Environment • In a single-celled amoeba, every part of the cell’s membrane touches the outside world, where exchange with the watery environment can occur. • A hydra has a body wall only two cell layers thick. • Both layers of cells are bathed in pond water, which enters the digestive sac through the mouth. • Every cell of the hydra can thus exchange materials through direct contact with the aqueous environment. © 2016 Pearson Education, Inc. Figure 21.9 Mouth Gastrovascular cavity Exchange Exchange Exchange (a) Single cell (b) Two cell layers © 2016 Pearson Education, Inc. Figure 21.9-1 © 2016 Pearson Education, Inc. Exchanges with the External Environment • Exchange with the environment is more complicated for complex, multilayered animals. • Each cell in a multicellular organism has a plasma membrane where exchange can occur. • But this exchange only works if all the cells of the animal have access to a suitable watery environment. © 2016 Pearson Education, Inc. Exchanges with the External Environment • Figure 21.10 shows a schematic model of an animal body, highlighting the three organ systems (digestive, respiratory, and urinary) that exchange materials with the external environment. • The circulatory system connects to nearly every organ system as it • transports needed materials from the environment to the body’s tissues and • carries wastes away. © 2016 Pearson Education, Inc. Figure 21.10 External environment CO2 O Food 2 Mouth Animal Respiratory system Digestive system Interstitial fluid Heart Nutrients Circulatory system Body cells Urinary system Anus Unabsorbed matter (feces) © 2016 Pearson Education, Inc. Metabolic waste products (such as urine) Exchanges with the External Environment • Complex animals have evolved extensively folded or branched internal surfaces that maximize surface area for exchange with the immediate environment. • Lungs exchange oxygen and carbon dioxide with the air you breathe. • The epithelium of the lungs has a very large total surface area. © 2016 Pearson Education, Inc. Figure 21.11 © 2016 Pearson Education, Inc. Regulating The Internal Environment • Animals adjust to a changing environment. © 2016 Pearson Education, Inc. Homeostasis • The internal environment of vertebrates includes the interstitial fluid that • fills the spaces between cells and • exchanges nutrients and wastes with microscopic blood vessels. • Homeostasis, which literally means “steady state,” is the tendency to maintain relatively constant conditions in the internal environment even when the external environment changes. © 2016 Pearson Education, Inc. Figure 21.12 Animal’s internal environment External environment 37C HOMEOSTATIC MECHANISMS 39C 38C 4C Large external changes © 2016 Pearson Education, Inc. Small internal changes Thermoregulation • The homeostatic mechanism that controls temperature is called thermoregulation. • The ability to maintain a body temperature substantially warmer than the surrounding environment is characteristic of endotherms, animals such as mammals and birds that derive most of their body heat from their own metabolism. • In contrast, ectotherms, which include most invertebrates, fishes, amphibians, and nonbird reptiles, obtain their body heat primarily by absorbing it from their surroundings. © 2016 Pearson Education, Inc. Thermoregulation • You have a number of structures and mechanisms that aid in thermoregulation. • When your body temperature falls below normal, your brain’s control center sends signals that trigger changes that will bring it back to normal. • Blood vessels near your body’s surface constrict (reducing heat loss from your body surface) and muscles contract, causing you to shiver. • When body temperature gets too high, the control center sends signals to dilate the blood vessels near your skin and activate sweat glands, allowing excess heat to escape. © 2016 Pearson Education, Inc. Thermoregulation • Fever, an abnormally high internal temperature is a body-wide response that usually indicates an ongoing fight against infection. • Many people mistakenly believe that the invading microbes themselves cause a fever. In fact, the cause is usually the body’s fight against the microbes. • A moderate fever of 38–39°C (100–102°F), however, discourages bacterial growth and speeds the body’s internal defenses. © 2016 Pearson Education, Inc. Figure 21.14 Skin Sweat gland Response: 1. Blood vessels dilate 2. Sweat is produced Control center in brain activates cooling mechanisms Stimulus: Body temperature is above set point Body temperature drops Set point: Body temperature near 37C (98.6F) Body temperature rises Skin © 2016 Pearson Education, Inc. Stimulus: Body temperature is below set point Response: 1. Blood vessels constrict 2. Person shivers 3. Metabolic rate increases Control center in brain activates warming mechanisms Figure 21.14-1 Skin Sweat gland Response: 1. Blood vessels dilate 2. Sweat is produced Stimulus: Body temperature is above set point Body temperature drops Set point: Body temperature near 37C (98.6F) © 2016 Pearson Education, Inc. Control center in brain activates cooling mechanisms Figure 21.14-2 Set point: Body temperature near 37C (98.6F) Stimulus: Body temperature is below set point Body temperature rises Skin © 2016 Pearson Education, Inc. Response: 1. Blood vessels constrict 2. Person shivers 3. Metabolic rate increases Control center in brain activates warming mechanisms The Process of Science: How Does a Python Warm Her Eggs? • Observation: A female Burmese python incubating her eggs • wraps her body around them and • frequently contracts the muscles in her coils. © 2016 Pearson Education, Inc. The Process of Science: How Does a Python Warm Her Eggs? • Hypothesis: The snake’s muscle contractions elevate its body temperature for transfer of heat to its eggs. • Experiment: • Researchers placed a python and her eggs in a chamber and varied the chamber’s temperature. • They monitored the rate of the python’s muscle contractions and took into account the snake’s oxygen uptake, a measure of the rate of cellular respiration. © 2016 Pearson Education, Inc. The Process of Science: How Does a Python Warm Her Eggs? • Results: The python’s oxygen consumption increased when the temperature in the chamber decreased. © 2016 Pearson Education, Inc. O2 consumption (mL O2/hr) per kg Figure 21.15 © 2016 Pearson Education, Inc. 120 100 80 60 40 20 0 5 10 15 20 25 30 Contractions per minute 35 Osmoregulation • Living cells depend on a precise balance of • water and • solutes. • Osmoregulation is the control of the gain or loss of • water and • dissolved solutes, such as the ions of NaCl and other salts. © 2016 Pearson Education, Inc. Osmoregulation • Saltwater fish lose water by osmosis because there is less salt in their tissues than the water they swim in. • Freshwater fish have the opposite problem: The external solute concentration is low, so water enters the fish by osmosis. • Most land animals lose water through urinating, defecating, breathing, and perspiring but can counterbalance the loss by eating and drinking © 2016 Pearson Education, Inc. Figure 21.16 © 2016 Pearson Education, Inc. Interconnections within Systems: Homeostasis in the Urinary System • The urinary system plays a central role in osmoregulation, regulating the amount of water and solutes in body fluids by retaining water when we are dehydrated and expelling it when we are hydrated. • Besides osmoregulation, the urinary system plays another important role—the excretion of wastes. © 2016 Pearson Education, Inc. Interconnections within Systems: Homeostasis in the Urinary System • In humans, the two kidneys • are the main processing centers and • contain nearly 100 miles of thin tubes called tubules and an intricate network of capillaries. © 2016 Pearson Education, Inc. Interconnections within Systems: Homeostasis in the Urinary System • As blood circulates through the kidneys, a fraction of it is filtered and plasma enters the kidney tubules, forming filtrate. • Filtrate contains • valuable substances that need to be reclaimed (such as water and glucose) and • substances to be eliminated, such as urea. © 2016 Pearson Education, Inc. Interconnections within Systems: Homeostasis in the Urinary System • The human urinary system includes • the circulatory system, • the kidneys, • nephrons, the functional units within the kidneys, and • the urinary bladder, where urine is stored. © 2016 Pearson Education, Inc. Figure 21.17 Filter Tubule Renal artery (red) and renal vein (blue) Branch of renal artery Collecting duct Branch of renal vein Kidney Ureter Urinary bladder Ureter Urethra (b) Kidney (cutaway view) (a) Urinary system © 2016 Pearson Education, Inc. To ureter (c) Blood supply to a nephron Figure 21.17-1 Renal artery (red) and renal vein (blue) Kidney Ureter Urinary bladder Urethra (a) Urinary system © 2016 Pearson Education, Inc. Figure 21.17-2 Filter Tubule Branch of renal artery Collecting duct Branch of renal vein To ureter Ureter (b) Kidney (cutaway view) © 2016 Pearson Education, Inc. (c) Blood supply to a nephron Interconnections within Systems: Homeostasis in the Urinary System • Nephrons • carry out the functions of the urinary system, • consist of a tubule and its associated blood vessels, and • number more than a million in a kidney. © 2016 Pearson Education, Inc. Interconnections within Systems: Homeostasis in the Urinary System • Nephrons perform four key functions: 1. Filtration occurs as water and other small molecules are forced out of the blood when it passes through capillary walls into the kidney tubule, forming filtrate. 2. Reabsorption reclaims water and valuable solutes from the filtrate and returns them to the blood. 3. Secretion of certain substances, such as some ions and drugs, that are transported into the filtrate. 4. Excretion of urine from the kidneys to the outside. © 2016 Pearson Education, Inc. Figure 21.18 Filtration Renal artery Filtrate Reabsorption Renal vein Secretion Capillaries Tubule Excretion © 2016 Pearson Education, Inc. Urine Interconnections within Systems: Homeostasis in the Urinary System • Hormones regulate the kidney’s nephrons to maintain water balance and are central to the interconnections of the nervous, endocrine, and urinary systems. © 2016 Pearson Education, Inc. Interconnections within Systems: Homeostasis in the Urinary System • Understanding filtration, reabsorption, and secretion will help you see why urine samples are often used to assess health. • The presence of glucose in a urine sample suggests diabetes, a serious condition in which the blood glucose level is elevated. • Drugs are secreted into urine and can be detected there. • Pregnancy can be confirmed by the presence of a specific hormone excreted only in the urine of pregnant women. © 2016 Pearson Education, Inc. Interconnections within Systems: Homeostasis in the Urinary System • Factors affecting urine composition include • the environment, • presence of disease, • secretions from the various harmless microbes that can live in the lower part of the urethra, and • diet. © 2016 Pearson Education, Inc. Figure 21.19 © 2016 Pearson Education, Inc. Evolution Connection: Adaptations for Thermoregulation • Natural selection has promoted a wide variety of adaptations for thermoregulation including anatomical, physiological, and behavioral adaptations. © 2016 Pearson Education, Inc. Evolution Connection: Adaptations for Thermoregulation • A major anatomical adaptation in mammals and birds is insulation, consisting of • hair (fur), • feathers, or • fat layers. © 2016 Pearson Education, Inc. Evolution Connection: Adaptations for Thermoregulation • Some adaptations are physiological, such as • land mammals and birds reacting to cold by raising their fur or feathers, • hormonal changes tending to boost the metabolic rate of some birds and mammals, increasing their heat production in cold weather, • shivering to produce heat as a metabolic by-product of the contraction of skeletal muscles, and • panting and sweating to greatly increase cooling. © 2016 Pearson Education, Inc. Figure 21.20 METHODS OF THERMOREGULATION Anatomical Adaptations (such as hair, fat, and feathers) © 2016 Pearson Education, Inc. Behavioral Adaptations Physiological Adaptations (such as panting, shivering, (such as bathing, basking, hibernating, and migrating) and sweating) Figure 21.20-1 Anatomical Adaptations (such as hair, fat, and feathers) © 2016 Pearson Education, Inc. Figure 21.20-2 Physiological Adaptations (such as panting, shivering, and sweating) © 2016 Pearson Education, Inc. Figure 21.20-3 Behavioral Adaptations (such as bathing, basking, hibernating, and migrating) © 2016 Pearson Education, Inc. Figure 21.20-4 © 2016 Pearson Education, Inc. Evolution Connection: Adaptations for Thermoregulation • A variety of behavioral responses can regulate body temperature. • Some birds and butterflies migrate seasonally to more suitable climates. • Other animals, such as desert lizards, bask in the sun when it is cold and find cool, damp areas or burrows when it is hot. • Emperor penguins huddle together to stay warm. • Many animals cool themselves by bathing. © 2016 Pearson Education, Inc. Figure 21.UN01 HIERARCHICAL ORGANIZATION OF ANIMALS Level Description Cell The basic unit of all living organisms Example Muscle cell Tissue A collection of similar cells performing a specific function Cardiac muscle Organ Multiple tissues forming a structure that performs a specific function Heart Organ system A team of organs that work together Circulatory system Organism © 2016 Pearson Education, Inc. A living being, which depends on the coordination of all structural levels for homeostasis and survival Person Figure 21.UN01a HIERARCHICAL ORGANIZATION OF ANIMALS Level Description Cell The basic unit of all living organisms Example Muscle cell Tissue A collection of similar cells performing a specific function Cardiac muscle Organ Multiple tissues forming a structure that performs a specific function Heart © 2016 Pearson Education, Inc. Figure 21.UN01b HIERARCHICAL ORGANIZATION OF ANIMALS Level Description Organ system A team of organs that work together Example Circulatory system Organism © 2016 Pearson Education, Inc. A living being, which depends on the coordination of all structural levels for homeostasis and survival Person Figure 21.UN02 Muscle (contracts) Connective (supports organs) Epithelial (covers body surfaces and organs) © 2016 Pearson Education, Inc. Nervous (relays and integrates information) Figure 21.UN03 Blood Capillaries Tubule Filtration Water and small molecules enter the tubule. Reabsorption Water and valuable solutes are returned to the blood. Secretion Specific substances are removed from the blood. Urine © 2016 Pearson Education, Inc. Excretion Urine exits the body. Figure 21.UN04 Body temperature (C) 40 River otter 30 20 Largemouth bass 10 0 0 10 20 30 Ambient (environmental) temperature (C) © 2016 Pearson Education, Inc. 40