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Chapter 21 Unifying Concepts of Animal Structure and Function PowerPoint® Lectures for Campbell Essential Biology, Fifth Edition, and Campbell Essential Biology with Physiology, Fourth Edition – Eric J. Simon, Jean L. Dickey, and Jane B. Reece Lectures by Edward J. Zalisko © 2013 Pearson Education, Inc. Biology and Society: An Avoidable Tragedy • Our bodies are kept in a narrow temperature range. • When we exercise, our bodies are cooled by – evaporation of sweat on the skin and – expansion of blood vessels near the skin surface. © 2013 Pearson Education, Inc. Figure 21.0 Biology and Society: An Avoidable Tragedy • Extreme conditions can lead to – loss of consciousness in heat exhaustion, – even higher body temperatures, which can disrupt the brain’s control center, and – heat stroke, a life-threatening emergency. © 2013 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. © 2013 Pearson Education, Inc. Figure 21.1-1 Cellular level: Muscle cell Figure 21.1-2 Cellular level: Muscle cell Tissue level: Cardiac muscle Figure 21.1-3 Cellular level: Muscle cell Tissue level: Cardiac muscle Organ level: Heart Figure 21.1-4 Cellular level: Muscle cell Tissue level: Cardiac muscle Organ level: Heart Organ system level: Circulatory system Figure 21.1-5 Cellular level: Muscle cell Tissue level: Cardiac muscle Organ level: Heart Organ system level: Circulatory system Organism level: Multiple organ systems functioning together 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 A living being, which depends on the coordination of all structural levels for homeostasis and survival Person Form Fits Function • Analyzing a biological structure gives us clues about – what it does and – how it works. © 2013 Pearson Education, Inc. Figure 21.2-3 (b) At the organ level (a) At the organism level (c) At the cellular level Form Fits Function • 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. © 2013 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. © 2013 Pearson Education, Inc. Epithelial Tissue • 1. Epithelial tissue, also known as epithelium, – covers the internal and external surfaces of the body and – lines organs and cavities within the body. • Cells of epithelial tissues – are fused together, – form a protective barrier, and – fall off and are continuously renewed. © 2013 Pearson Education, Inc. Figure 21.3-3 Some examples of organs lined with epithelial tissue: Heart Lung Stomach Small intestine Large intestine Urinary bladder Epithelial tissue lining esophagus Epithelial cells Epithelial tissue lining small intestine Connective Tissue • 2. Connective tissues have a sparse population of cells in an extracellular matrix consisting of a web of protein fibers within a uniform foundation that may be liquid, jellylike, or solid. • The structure of connective tissue is correlated with its functions: – to bind and – support other tissues. © 2013 Pearson Education, Inc. Figure 21.4 (a) Loose connective tissue (b) Adipose tissue (c) Blood (d) Fibrous connective tissue (f) Bone (e) Cartilage Connective Tissue • Loose connective tissue – is the most widespread connective tissue, – binds epithelia to underlying tissues, and – holds organs in place. © 2013 Pearson Education, Inc. Connective Tissue • Adipose tissue – stores fat, – stockpiles energy, and – pads and insulates the body. © 2013 Pearson Education, Inc. Connective Tissue • Blood – is a connective tissue and – contains red and white blood cells suspended in a liquid called plasma. © 2013 Pearson Education, Inc. Connective Tissue • Fibrous connective tissue – has a dense matrix of collagen and – forms tendons and ligaments. © 2013 Pearson Education, Inc. Connective Tissue • Cartilage – is strong but flexible, – has no blood vessels, so it heals very slowly, – functions as a flexible, boneless skeleton, and – forms the shock-absorbing pads that cushion the ends of bones including the vertebrae of the spinal column. © 2013 Pearson Education, Inc. Connective Tissue • Bone – is a rigid connective tissue and – has a matrix of collagen fibers hardened with deposits of calcium salts. © 2013 Pearson Education, Inc. Muscle Tissue • 3. 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. © 2013 Pearson Education, Inc. Figure 21.5 (a) Skeletal muscle (b) Cardiac muscle (c) Smooth muscle Muscle Tissue • Skeletal muscle is – attached to bones by tendons, – responsible for voluntary movements, and – striated because the contractile proteins form a banded pattern. © 2013 Pearson Education, Inc. Muscle Tissue • Cardiac muscle is – found only in heart tissue, – composed of cells that are branched and striated, – involuntary, and – responsible for the contraction of the heart. © 2013 Pearson Education, Inc. Muscle Tissue • Smooth muscle is – named for its lack of obvious stripes, – found in the walls of various organs such as intestines and blood vessels, and – involuntary. © 2013 Pearson Education, Inc. Nervous Tissue • 4. Nervous tissue – makes communication of sensory 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. © 2013 Pearson Education, Inc. Figure 21.6 Brain Signal-receiving Cell body extensions Spinal cord Nerve LM Signaltransmitting extension Figure 21.6a Brain Spinal cord Nerve Figure 21.6b Signal-receiving Cell body extensions LM Signaltransmitting extension Organs and Organ Systems • An organ consists of two or more tissues packaged into one working unit that performs a specific function. • Examples include the heart, liver, stomach, brain, and small intestines. © 2013 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 Epithelial tissue Organs and Organ Systems • Organ systems are teams of organs – that work together and – perform vital body functions. © 2013 Pearson Education, Inc. Figure 21.8a Skeletal system: supports body and anchors muscles Bone Cartilage Figure 21.8b Circulatory system: transports substances throughout body Heart Blood vessels Figure 21.8c Respiratory system: Nasal cavity Pharynx exchanges O2 and CO2 between blood and air Larynx Trachea Bronchus Lung Figure 21.8d Muscular system: moves the body Skeletal muscles Figure 21.8e Digestive system: breaks down food and absorbs nutrients Mouth Esophagus Liver Stomach Large intestine Small intestine Anus Figure 21.8f Urinary system: rids body of certain wastes Kidney Ureter Urinary bladder Urethra Figure 21.8g Endocrine system: secretes hormones that regulate body Hypothalamus Pituitary gland Parathyroid gland Thyroid gland Adrenal gland Pancreas Testis (male) Ovary (female) Figure 21.8h Reproductive system: produces gametes and offspring Seminal vesicles Prostate gland Oviduct Vas deferens Ovary Uterus Vagina Penis Urethra Testis Figure 21.8i Integumentary System (skin): protects body Hair Skin Nail Figure 21.8j Lymphatic and immune system: defends against disease Thymus Spleen Lymph nodes Lymphatic vessels Figure 21.8k Nervous system: processes sensory information and controls responses Brain Sense organ (ear) Spinal cord Nerves EXCHANGES WITH THE EXTERNAL ENVIRONMENT • Every organism is an open system, continuously exchanging chemicals and energy with its surroundings to survive. • An animal’s size and shape affect its exchanges with its surrounding environment. • All living cells must be bathed in a watery solution so that exchange of materials can occur. © 2013 Pearson Education, Inc. EXCHANGES WITH THE EXTERNAL ENVIRONMENT • The entire surface area of a single-celled amoeba is in contact with its watery environment. • A hydra has a body wall only two cell layers thick. • Both layers of cells are bathed in pond water, enabling exchange with the environment. © 2013 Pearson Education, Inc. Figure 21.9 Mouth Gastrovascular cavity Exchange Exchange Exchange (a) Single cell (b) Two cell layers EXCHANGES WITH THE EXTERNAL ENVIRONMENT • Animals with complex body forms face the same basic problems. Every cell must – be bathed in fluid and – have access to resources from the outside environment. © 2013 Pearson Education, Inc. 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 – have a very large total surface area and – exchange oxygen and carbon dioxide with the air you breathe. © 2013 Pearson Education, Inc. Figure 21.10 EXCHANGES WITH THE EXTERNAL ENVIRONMENT • Animals use three organ systems to exchange materials with the external environment: 1. digestive, 2. respiratory, and 3. urinary. © 2013 Pearson Education, Inc. EXCHANGES WITH THE EXTERNAL ENVIRONMENT • The circulatory system – connects to nearly every organ system, – transports needed materials from the environment to the body’s tissues, and – carries waste away. © 2013 Pearson Education, Inc. Figure 21.11 External environment Mouth Food CO2 O2 Animal Respiratory system Digestive system Interstitial fluid Heart Nutrients Circulatory system Body cells Urinary system Anus Unabsorbed matter (feces) Metabolic waste products (such as urine) REGULATING THE INTERNAL ENVIRONMENT • Animals adjust to a changing environment. © 2013 Pearson Education, Inc. Homeostasis • Homeostasis is the body’s ability to stay relatively unchanged even when the world around it changes. • The internal environment of vertebrates includes the interstitial fluid that – fills the spaces between cells and – exchanges nutrients and wastes with microscopic blood vessels. © 2013 Pearson Education, Inc. Figure 21.12 Animal’s internal environment External environment HOMEOSTATIC MECHANISMS Large external changes Small internal changes Negative and Positive Feedback • Most mechanisms of homeostasis depend on a principle called negative feedback, – in which the results of a process inhibit that same process, – such as a thermostat that turns off a heater when room temperature rises to the set point. © 2013 Pearson Education, Inc. Figure 21.13 Response: Heating stops Thermostat (control center) turns heater off Stimulus: Room temperature is above set point Room temperature drops Set point: Room temperature 20°C (68°F) Stimulus: Room temperature is below set point Room temperature rises Response: Heating starts Thermostat (control center) turns heater on Negative and Positive Feedback • Less common is positive feedback, – in which the results of a process intensify that same process, – such as uterine contractions during childbirth. © 2013 Pearson Education, Inc. https://www.youtube.com/watch?v=ufv9Txb7n U0 Homeostasis (12.40) https://www.youtube.com/watch?v=l6tu2mq1 aic Negative vs. Positive Feedback (11.43) Thermoregulation • Thermoregulation is the maintenance of internal body temperature. – Endotherms – such as mammals and birds – derive the majority of their body heat from their metabolism. © 2013 Pearson Education, Inc. Thermoregulation – Ectotherms – such as most invertebrates, fishes, amphibians, and nonbird reptiles – obtain body heat primarily by absorbing it from their surroundings. © 2013 Pearson Education, Inc. Thermoregulation • Humans have homeostatic mechanisms that aid in thermoregulation, which – cool or – heat the body. © 2013 Pearson Education, Inc. Thermoregulation • Fever – is an abnormally high internal body temperature and – usually indicates an ongoing fight against infection. © 2013 Pearson Education, Inc. Osmoregulation • Living cells depend on a precise balance of – water and – solutes (dissolved substances). • Osmoregulation is the control of the gain or loss of – water and – dissolved solutes, such as the ions of NaCl and other salts. © 2013 Pearson Education, Inc. Osmoregulation • Osmoconformers – have internal and external environments with similar solute concentrations and – include most marine invertebrates. • Osmoregulators – actively regulate their water loss or gain and – include freshwater animals, most marine vertebrates, and all land animals. © 2013 Pearson Education, Inc. Figure 21.16 Osmoconformer Osmoregulator Homeostasis in the Urinary System • The human urinary system – plays a central role in homeostasis, – forms and excretes waste-carrying urine, and – regulates the amount of water and solutes in body fluids. © 2013 Pearson Education, Inc. Homeostasis in the Urinary System • In humans, the two kidneys – are the main processing centers and – contain many fine tubes called tubules and an intricate network of capillaries. © 2013 Pearson Education, Inc. 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. © 2013 Pearson Education, Inc. 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. © 2013 Pearson Education, Inc. Figure 21.17 (b) Kidney (a) Urinary system (c) A nephron and collecting duct 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. © 2013 Pearson Education, Inc. Figure 21.17c Filter Branch of renal artery Tubule Collecting duct Branch of renal vein To ureter (c) A nephron and collecting duct Homeostasis in the Urinary System • Nephrons perform four key functions. 1. Filtration, forcing water and other small molecules from the blood to form filtrate 2. Reabsorption of water and valuable solutes back into the blood 3. Secretion of certain substances, such as ions and drugs, into the filtrate 4. Excretion of urine from the kidneys to the outside © 2013 Pearson Education, Inc. Figure 21.18 Filtration Reabsorption Renal artery Secretion Filtrate Renal vein Capillaries Tubule Excretion Urine Homeostasis in the Urinary System • Hormonal control of the nephrons allows the body to control its internal concentration of – water and – dissolved molecules. © 2013 Pearson Education, Inc. Homeostasis in the Urinary System • Kidney failure can be caused by – injury, – illness, or – prolonged use of pain relievers (including over-thecounter medicines such as aspirin), alcohol, or other drugs. • One option for treatment of kidney failure is dialysis, filtration of blood by a machine that mimics the action of a nephron. © 2013 Pearson Education, Inc. Figure 21.19 Line from artery to apparatus Pump Line from apparatus to vein Tubing made of a selectively permeable membrane Dialyzing solution Fresh dialyzing solution Used dialyzing solution (with urea and excess salts) Evolution Connection: Adaptations for Thermoregulation • Animals regulate their body temperatures using adaptations that are – anatomical, – physiological, and/or – behavioral. © 2013 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. © 2013 Pearson Education, Inc. Evolution Connection: Adaptations for Thermoregulation • Some adaptations are physiological, such as – changes in metabolic rate, – shivering, or – panting and sweating. © 2013 Pearson Education, Inc. Figure 21.20 METHODS OF THERMOREGULATION Anatomical Adaptations (such as hair, fat, and feathers) Physiological Behavioral Adaptations Adaptations (such as bathing, (such as panting, basking, hibernating, shivering, and sweating) and migrating Fat Hair Panting Bathing