1. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology: Concepts and Connections, Fifth Edition – Campbell, Reece, Taylor, and Simon Lectures by Chris Romero Chapter 20 Unifying Concepts of Animal Structure and Function

2. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Climbing the Walls Like Spiderman, geckos can walk up a wall and across ceilings The gecko's ability to "stick" to surfaces results from special structural adaptations of its body – Setae, hairs made of protein on the gecko's toes, contain many spatulae – Molecules on the spatulae are attracted to molecules on the walking surface The correlation between structure and function is an overarching concept of biology

5. THE HIERARCHY OF STRUCTURAL ORGANIZATION IN AN ANIMAL 20.1 Structure fits function in the animal body Anatomy is the study of structure Physiology studies how structures function The functions of the various parts of the body result from their specific structures – Example: Flight apparatus of birds provides strength, support, insulation, stability, minimal weight Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

6. LE 20-01 Shaft ForearmWrist Finger 1 Feather structure Hook Barbule Finger 2 Finger 3 Palm Internal bone structure Shaft Barb

7. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 20.2 Animal structure has a hierarchy Structure in the living world is organized in a series of hierarchical levels – Cell: smallest independent unit of life – Tissue: integrated group of cells that perform a specific function – Organ: two or more types of tissues that together perform a specific task – Organ system: multiple organs that together perform a vital body function – Organism: integrated unit made up of a number of organ systems functioning together

8. LE 20-02 Cellular level Muscle cell Tissue level Muscle tissue Organ level Heart Organ system level Circulatory system Organism level Many organ systems functioning together

9. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 20.3 Tissues are groups of cells with a common structure and function The cells composing a tissue are specialized to perform a specific function In almost all animals, most body cells are organized into four main categories of tissues – Epithelial – Connective – Muscle – Nervous

10. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 20.4 Epithelial tissue covers the body and lines its organs and cavities Epithelial tissue occurs as sheets of closely packed cells anchored to underlying tissues by a basement membrane Categories of epithelial tissues – Simple: single layer of cells – Stratified: multiple layers of cells – Shapes: squamous, cuboidal, or columnar Epithelial tissue functions in protection, secretion, and exchange

11. LE 20-04 Free surface of epithelium Basement membrane Underlying tissue Cell nuclei Simple squamous epithelium (lung) Simple cuboidal epithelium (kidney) Simple columnar epithelium (intestine) Stratified squamous epithelium (skin) Rapidly dividing epithelial cells Layers of dead cells Stratified squamous epithelium (esophagus) Colorized SEM

12. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 20.5 Connective tissue binds and supports other tissues The various types of connective tissue consist of sparse cells in an extracellular gel matrix – Loose connective tissue – Fibrous connective tissue – Adipose tissue – Cartilage – Bone – Blood

13. LE 20-05 Fat droplets Adipose tissue Cell nucleus White blood cells Fibrous connective tissue (forming a tendon) Cell Collagen fiber Elastic fibers Loose connective tissue (under the skin) Red blood cell Blood Plasma Bone Bone- forming cells Matrix Central canal Cartilage (at the end of a bone) Cartilage- forming cells Matrix Collagen fiber

14. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 20.6 Muscle tissue functions in movement Muscle tissue consists of bundles of long cells called muscle fibers – Skeletal muscle is responsible for voluntary body movements – Cardiac muscle forms the contractile tissue of the heart – Smooth muscle moves the walls of internal organs such as the stomach, bladder, and arteries

15. LE 20-06 Nucleus Muscle fiber Unit of muscle contraction Skeletal muscle Cardiac muscle Nucleus Muscle fiber Nucleus Muscle fiber Junction between two cells Smooth muscle

16. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 20.7 Nervous tissue forms a communication network Nervous tissue senses stimuli and rapidly transmits information through the body The neuron is the structural and functional unit of nervous tissue – Specialized to conduct electrical impulses – Consists of cell body, axon, and dendrites – Nourished by supporting cells

17. LE 20-07 Cell body Nucleus Cell extensions LM 330 

18. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings CONNECTION 20.8 Artificial tissues have medical uses Many, but not all, body tissues are self-repairing Artificial tissues can assist in the healing of tissues that cannot recover on their own – Skin – Cartilage, teeth (under study)

20. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 20.9 Organs are made up of tissues Each organ is made of several tissues that collectively perform specific functions – In some organs, tissues are arranged in layers An organ performs functions that none of its component tissues could carry out alone

21. LE 20-09 Lumen Connective tissue Epithelial tissue (columnar epithelium) Smooth muscle tissue (2 layers) Connective tissue Epithelial tissue Lumen Small intestine (cut open)

22. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 20.10 Organ systems work together to perform life functions There are twelve major organ systems in vertebrate animals – Digestive system – Respiratory system – Circulatory system – Immune system – Lymphatic system

23. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings – Excretory system – Endocrine system – Nervous system – Integumentary system – Skeletal system – Muscular system – Reproductive systems

24. LE 20-10a Mouth Liver Esophagus Stomach Small intestine Large intestine Anus Digestive system

25. LE 20-10b Lung Bronchus Trachea Larynx Nasal cavity Respiratory system

26. LE 20-10c Circulatory system Heart Blood vessels

27. LE 20-10d-e Lymph vessels Lymph nodes Spleen Thymus Bone marrow Immune system Lymphatic system

28. LE 20-10f Kidney Ureter Urinary bladder Urethra Excretory system

29. LE 20-10g Pituitary gland Thyroid gland Adrenal gland Thymus Pancreas Testis (male) Ovary (female) Endocrine system

30. LE 20-10h Sense organ Nervous system Spinal cord Nerves Brain

31. LE 20-10i Integumentary system Hair Skin Nails

32. LE 20-10j Cartilage Bones Skeletal system

33. LE 20-10k Skeletal muscles Muscular system

34. LE 20-10l Prostate gland Vas deferens MaleFemale Urethra Penis Testis Oviduct Ovary Uterus Vagina Reproductive system

35. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings CONNECTION 20.11 New imaging technology reveals the inner body X-Rays – High-energy radiation passes through soft tissue – Hard structures (teeth, bones, tumors) show up most clearly on film – Problems: don't show soft tissue, are only 2- D, can cause cancer in large doses

36. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Computed tomography (CT) – Computer-assisted X-ray technique – Produces images of a series of thin cross sections through the body – Images can be studied individually or combined into 3-D views – Excellent diagnostic tool, especially for abdomen and brain

39. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Magnetic resonance imaging (MRI) – Uses powerful magnets to align hydrogen atoms in water – Allows visualization of soft tissues; dense structures nearly invisible Particularly good for detecting problems in nervous tissue surrounded by bone Magnetic resonance microscopy (MRM) – Provides three-dimensional images of very small structures

41. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Positron-emission tomography (PET) – Scanner detects radiation taken up during metabolism – Yields information about metabolic processes at specific locations in the body – Most valuable for measuring brain activity Alzheimer's disease, epilepsy, stroke

42. LE 20-11d HEARING WORDS SEEING WORDS SPEAKING WORDS GENERATING WORDS MAX MIN

43. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings EXCHANGES WITH THE EXTERNAL ENVIRONMENT 20.12 Structural adaptations enhance exchange between animals and their environment An animal must exchange materials with its environment – Oxygen and nutrients enter – CO 2 and metabolic wastes exit – Only molecules dissolved in water can move across the plasma membrane In small, simple animals, each cell has enough surface area to meet its needs by direct diffusion and active transport

44. LE 20-12a Mouth Diffusion Two cell layers Gastrovascular cavity

45. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Larger, complex animals have less surface area relative to volume – Rely on specialized surfaces for exchanging materials with the environment Interstitial fluid provides for indirect exchange between blood and body cells Branching and folding increase surface area of the lungs, intestines, and kidneys

46. LE 20-12b External environment Mouth Food CO 2 O2O2 Animal Respiratory system Digestive system Circulatory system Nutrients Interstitial fluid Body cells Excretory system Intestine Anus Unabsorbed matter (feces) Metabolic waste products (urine) Heart Blood

48. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 20.13 Animals regulate their internal environment The internal environment of a vertebrate is the interstitial fluid surrounding the cells In response to changes in external conditions, animals regulate their internal environment to achieve homeostasis, an internal steady state – Homeostasis is a dynamic state with constant small fluctuations

50. LE 20-13b External environment Internal environment Small fluctuations Large fluctuations Homeostatic mechanisms

51. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 20.14 Homeostasis depends on negative feedback In negative feedback, a change in a variable triggers mechanisms that reverse the change Negative feedback mechanisms keep internal variables fairly constant, with small fluctuations around set points In animals, most control centers that maintain homeostasis are located in the brain

52. LE 20-14 Thermostat in brain activates cooling mechanisms Temperature rises above normal Temperature increases Blood vessels in skin dilate and heat escapes Thermostat shuts off warming mechanisms Homeostasis: Internal body temperature of approximately 36  38  C Thermostat shuts off cooling mechanisms Blood vessels in skin constrict, minimizing heat loss Skeletal muscles rapidly contract, causing shivering, which generates heat Sweat glands secrete sweat that evaporates, cooling body Temperature decreases Temperature falls below normal Thermostat in brain activates warming mechanisms

53. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Animation: Negative Feedback Animation: Negative Feedback Animation: Positive Feedback Animation: Positive Feedback