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Films for the Humanities & Sciences i ® A Wealth of Information. A World of Ideas. Instructor’s Guide The Human Body: How It Works CELLS, TISSUES, AND SKIN Introduction This program is part of the nine-part series The Human Body: How It Works. The series uses physiologic animations and illustrations, microscopic imaging, expert commentary, and footage of the body in motion to provide a thorough overview of the amazing human machine. The series includes: • • • • • • • • • Cells, Tissues, and Skin The Immune System Human Development and the Reproductive System The Respiratory System The Circulatory System The Skeletal and Muscular Systems Digestion and Nutrition The Endocrine System The Nervous System and the Senses Topics Chapter 1: The Basis of Life The program begins by introducing the idea that our cells, with their plasma membrane, nucleus, organelles, and cytoplasm, are highly specialized structures that work together with other cells to allow us to survive. Chapter 2: Cell Membranes This section gives an overview of the structure of the cell membrane, helping students understand how oxygen and nutrients can pass into the cell. Animations portray the semi-permeable, phospholipid bilayer, the transmembrane and peripheral proteins, and the function of the glycocalyx. Also covered: Self-cells. Films for the Humanities & Sciences ® Copyright © 2009 Films for the Humanities & Sciences® • www.films.com • 1-800-257-5126 39505 1 The Human Body: How It Works CELLS, TISSUES, AND SKIN INSTRUCTOR’S GUIDE Chapter 3: Movement Through Cell Membranes The process of diffusion is the focus of this chapter. The narrator explains the mechanics of simple diffusion, facilitated diffusion, osmosis, and filtration, along with the ways in which hypertonic, hypotonic, and isotonic solutions affect a cell. The difference between active and passive transport processes is covered, touching on solute pumping, endocytosis, and exocytosis. Also covered: The concentration gradient; carrier proteins; vesicles. Chapter 4: Cytoplasm The elements of cytoplasm (cytosol, inclusions, and organelles) are identified before the program proceeds to highlight three important organelles — the endoplasmic reticulum, the Golgi apparatus, and mitochondria. Viewers learn why the microfilaments, intermediate filaments, and microtubules are integral to the composition of the cytoskeleton. Also covered: Centrioles. Chapter 5: The Nucleus This section begins with a description of the parts of the nucleus, then goes on to a discussion of the cell cycle. Interphase, the five stages of the mitotic phase, and and the process of cytokinesis are all detailed as parts of the cell cycle. Also covered: Chromatin; daughter cells; differentiation. Chapter 6: Tissues The four major categories of tissue — epithelial, connective, muscle, and nervous — are the main theme of this section. Viewers learn that tissues can also be classified by the shape of their cells (squamous, cuboidal, or columnar) and by the number of cell layers they contain (e.g., simple, stratified, and pseudo-stratified tissues). Chapter 7: Skin The last section of the program deals with the skin — its basic functions and layers, and some of the cells associated with it. Also covered: How keratinocytes and melanocytes protect the skin; fingerprints. Learning Objectives Students will learn… • The basic characteristics of our cells, including the plasma membrane, nucleus, organelles, and cytoplasm • The basic characteristics of the cell membrane, including transmembrane and peripheral proteins, and the glycocalyx • The passive transport processes of simple diffusion, facilitated diffusion, osmosis, and filtration • The active transport processes of solute pumping, endocytosis, and exocytosis Films for the Humanities & Sciences ® Copyright © 2009 Films for the Humanities & Sciences® • www.films.com • 1-800-257-5126 2 The Human Body: How It Works CELLS, TISSUES, AND SKIN INSTRUCTOR’S GUIDE • The parts and functioning of the cytoplasm (including the endoplasmic reticulum, Golgi apparatus, and mitochondria) and of the cytoskeleton • The stages of the cell cycle, and what occurs during each stage • The four categories of tissue, and classification of tissue by shape of cells, and number of cell layers • The main layers and sublayers of the skin Vocabulary active transport: The process of moving particles across a membrane against a concentration gradient. Active transport processes require the cell to expend energy. Solute pumping, endocytosis, and exocytosis are all active transport processes. anaphase: The fourth stage of mitosis in the cell cycle, during which the spindle fibers pull sister chromatids to opposite poles of the cell. carrier proteins: Proteins that transport a specific substance or group of substances through intracellular compartments or in extracellular fluids (e.g. in the blood), or across the cell membrane. cell cycle: The series of events involving the growth, replication, and division of a cell, thereby creating new cells: two “daughter cells” with identical sets of genes. The main stages of the cell cycle are interphase and mitosis (which is further broken down into five stages), and the process of cytokinesis. cell membrane: The semi-permeable membrane enclosing the cytoplasm of a cell. centriole: A type of organelle, the walls of which are usually composed of microtubules. Centrioles play an important role in cell division. centrosome: A small region near the nucleus in the cell cytoplasm, containing the centrioles, which is important in cell division. chromatin: A long, ribbon-like substance in the cell’s nucleus consisting of DNA, RNA, and histone proteins. The histone proteins provide a physical means for packing the very large DNA molecules into the very small space within the nucleus of the cell. columnar cells: Epithelial cells that are shaped like a column or cylinder. Columnar cells are divided into simple (or unilayered), and stratified (or multi-layered). Films for the Humanities & Sciences ® Copyright © 2009 Films for the Humanities & Sciences® • www.films.com • 1-800-257-5126 3 The Human Body: How It Works CELLS, TISSUES, AND SKIN INSTRUCTOR’S GUIDE concentration gradient: The difference in the concentration of like molecules inside and outside of the cell. connective tissues: One of the four basic types of tissue in the human body, it is a type of tissue involved in the structure and support of the human body. Blood and bone are connective tissues; other connective tissues bind muscles to bone, fill spaces between cells, store fat, protect against infection, and help repair tissue damage. cuboidal cells: Epithelial cells that are cube-shaped. They may exist in single layers (simple cuboidal epithelium) or multiple layers (stratified cuboidal epithelium). cytokinesis: A process that occurs during the cell cycle that begins during anaphase and ends after the completion of mitosis, during which the cytoplasm is pinched in two, resulting in two daughter cells with identical sets of genes. cytoplasm: A clear, colorless semi-fluid that fills the area inside the cell membrane and outside of the nucleus. It consists of three main elements: cytosol, inclusions, and organelles. The cytoplasm contains water and nutrients for the cell. cytoskeleton: Structural support of the cell cytoplasm, composed of microfilaments, intermediate filaments, and microtubules. cytosol: The thick, semi-transparent fluid of the cytoplasm in which all other cytoplasmic elements are suspended. daughter cells: The cells that result from the reproductive division of one cell during mitosis or meiosis. Daughter cells are genetically identical to their parent cell. dermis: The layer of skin beneath the epidermis. The dermis contains the nerves, sensory receptors, most blood vessels, hair follicles, oil glands, and sweat glands. differentiation: The process whereby an individual cell expresses (turns on) some genes, and represses (turns off) others. This causes each cell to grow and develop into a specific type with a specialized function. Films for the Humanities & Sciences ® Copyright © 2009 Films for the Humanities & Sciences® • www.films.com • 1-800-257-5126 4 The Human Body: How It Works CELLS, TISSUES, AND SKIN INSTRUCTOR’S GUIDE diffusion: The process by which particles spread from regions of higher concentration to areas of lower concentration until equilibrium is attained. This process is absolutely critical for cells to survive. endocytosis: A type of active transport where large particles (such as bacteria) outside the cell are engulfed or enclosed within vesicles. endoplasmic reticulum (ER): A complex organelle composed of flattened sacs and elongated canals that twist through the cytoplasm, connecting and communicating with other organelles and the cell nucleus. ER is involved in the transport of proteins to be used in the cell membrane. epidermis: The outer, protective, nonvascular layer of the skin of vertebrates that covers the dermis. The epidermis is composed of five layers, or strata. epithelial cells: Cells forming the epithelium. Specialized epithelial cells produce hormones. epithelium: One of the four basic types of tissue in the human body, it is tissue composed of cells that line the cavities and surfaces of structures throughout the body. exocytosis: The process of endocytosis in reverse, often used to rid the cell of waste. facilitated diffusion: A type of diffusion in which carrier proteins help transport larger molecules (such as glucose and amino acids) across cell membranes. filtration: Liquid that has been passed through a filter, such as when water and solute particles are forced through membranes. glycocalyx: A fuzzy coat on a cell’s surface that provides highly specific biological markers that allow cells to recognize each other as self-cells. Golgi apparatus: An organelle that serves as the processing and transportation center of the cell. It receives proteins from the rough endoplasmic reticulum, adds any finishing touches, packages them in vesicles, and ships them out to specific locations. hypertonic: Having the higher osmotic pressure of two solutions. In a hypertonic situation, a higher solute concentration exists outside of a cell than inside it. This exerts osmotic pressure for water molecules to diffuse outside, where the concentration of water molecules is less. This causes the cell to shrink due to net water loss. Films for the Humanities & Sciences ® Copyright © 2009 Films for the Humanities & Sciences® • www.films.com • 1-800-257-5126 5 The Human Body: How It Works CELLS, TISSUES, AND SKIN INSTRUCTOR’S GUIDE hypotonic: Having the lower osmotic pressure of two fluids. In a hypotonic situation, the exterior solute concentration is lower than it is inside a cell. Water would tend to diffuse into the cell, causing it to swell. inclusions: Substances, such as nutrients or fat droplets, in the cytoplasm of a cell. integumentary system: A system of the body made up of the skin, hair, nails, and sweat and sebaceous (oil) glands. intermediate filaments: Structures within the cytoplasm that strengthen the cell and help it resist pulling forces. Intermediate filaments help form the cytoskeleton of a cell. interphase: The first stage of the cell cycle, it is a period of growth and development when a cell carries out its normal functions. isotonic: Pertaining to solutions characterized by equal osmotic pressure. Isotonic solutions will neither cause the cell to take on water, nor to lose it. keratinocyte: The most pervasive cell type of the epidermis. Keratinocytes produce a fibrous protein called keratin that gives the epidermis its protective qualities. melanocyte: A type of epidermal cell found in the stratum spinosum. Melanocytes produce melanin, which influences skin color and absorbs ultraviolet radiation. metaphase: The third stage of mitosis in the cell cycle, during which the chromosomes attached to the spindle fibers line up along the midline of the cell. microfilaments: Minute fibers in the cytoplasm that are involved with cell movement and changes in cell shape. Microfilaments help form the cytoskeleton of a cell. microtubules: Structures in the cytoplasm that help determine overall cell shape and the distribution of cellular organelles. Microtubules help form the cytoskeleton of a cell. mitochondria: Organelles in the cytoplasm of cells that supply the cells with ATP, the energy needed to perform cell functions. mitosis: The dividing of a somatic cell into two identical “daughter” cells via dividing and replicating of chromosomes, and then cytokinesis. “Mitosis” technically refers only to the separating and replicating of chromosomes in the nucleus, but generally is used to include the cytokinetic process of pinching the entire cell into two new cells as well. Films for the Humanities & Sciences ® Copyright © 2009 Films for the Humanities & Sciences® • www.films.com • 1-800-257-5126 6 The Human Body: How It Works CELLS, TISSUES, AND SKIN INSTRUCTOR’S GUIDE mitotic phase: Also called the M phase, it is the stage of cell division during which the cell undergoes the five stages of mitosis. muscle: One of the four basic types of tissue in the human body, it is classified as skeletal, smooth, or cardiac. nervous tissue: One of the four basic types of tissue in the human body, it makes up the brain, spinal cord, and peripheral nerves. nuclear envelope: Also called the nuclear membrane, it is the part of the cell’s nucleus that encloses the nucleoplasm. The nuclear envelope protects the cell’s DNA from accidental damage. nuclear lamina: A network of protein filaments in the cell’s nucleus, similar to the cytoskeleton, that lines the inner membrane and maintains the shape of the nucleus. nuclear pores: Openings in a nuclear membrane that regulate the entry and exit of large particles (such as nutrients and waste) between the nucleus and surrounding cytoplasm. nucleoli (singular is nucleolus): Rounded bodies within the nucleus of a cell where the subunits of ribosomes are assembled. nucleoplasm: Gel-like fluid within the nuclear envelope in which other nuclear elements are suspended. nucleus: In a cell, an organelle that contains DNA and RNA and directs the activity of the cell. The nucleus consists of the nuclear envelope, the nuclear lamina, nuclear pores, the nucleoli and other subnuclear bodies, chromatin, and nucleoplasm. The nucleus is where most DNA replication and RNA synthesis occurs. organelle: A specialized part of a cell that carries out particular functions for the cell; a cell organ. osmosis: The diffusion of fluids through semi-permeable membranes, flowing from the solution with the lower solute concentration into the solution with higher solute concentration. passive transport: The process of moving biochemicals and atomic or molecular substances across the cell membrane, and not requiring the cell to expend energy. Simple diffusion, facilitated diffusion, osmosis, and filtration are all types of passive transport processes. peripheral proteins: Proteins attached to either the inner or outer surface of the cell membrane. Films for the Humanities & Sciences ® Copyright © 2009 Films for the Humanities & Sciences® • www.films.com • 1-800-257-5126 7 The Human Body: How It Works CELLS, TISSUES, AND SKIN INSTRUCTOR’S GUIDE phospholipid bilayer: The double layer of phosphate and lipid (fat-like) molecules that separates and protects the cell from its environment. phospholipid molecule: A molecule that consists of a water-soluble, hydrophilic head and a nonwater soluble, hydrophobic tail. These molecules align themselves so that their heads face toward the inner and outer surfaces of the cell, while the tails line up in the center of the membrane. plasma membrane: Also called the cell membrane or phospholipid bilayer, it is the thin, semipermeable outer layer that separates the cell from its environment. The plasma membrane contains proteins that transport nutrients and waste products into and out of the cell. The membrane also contains receptor proteins that allow cells to receive signals from the environment and from other cells. prometaphase: The second stage of mitosis in the cell cycle, during which some of the spindle fibers attach to the chromosomes, causing them to move. prophase: The first stage of mitosis in the cell cycle, during which strands of chromatin form into chromosomes, spindle fibers appear from the centrosomes, and the nuclear envelope and nucleoli disappear. pseudo-stratified tissues: Tissues that contain a single layer of cells that appears to be stratified, but is not. Pseudo-stratified columnar cells line respiratory passages and reproductive organs. reticular: The lower layer of the dermis, it contains a combination of collagen and elastic fibers. This gives the skin its ability to stretch and return to its original shape. rough ER: Endoplasmic reticulum with ribosomes attached to its surface which synthesize all the proteins secreted from the cell. selectively permeable: Semi-permeable; having the ability to let some particles pass through, but not others. Cell membranes are selectively permeable. self-cells: Cells that are a part of the body, as opposed to cells like bacteria, that are not. simple diffusion: A type of diffusion in which substances such as oxygen and carbon dioxide are able to pass through the interior of the cell membrane without assistance. simple tissues: Tissues that have a single cell layer, such as the squamous epithelium that lines the air sacs in lungs and the walls of blood capillaries. Films for the Humanities & Sciences ® Copyright © 2009 Films for the Humanities & Sciences® • www.films.com • 1-800-257-5126 8 The Human Body: How It Works CELLS, TISSUES, AND SKIN INSTRUCTOR’S GUIDE smooth ER: ER without ribosomes on its surface. Smooth ER manufactures certain lipid molecules, whereas rough ER is involved with proteins. solute pumping: An active transport process in which substances are moved against concentration gradients by carrier proteins called solute pumps. solutes: Substances dissolved within other substances. squamous cells: Epithelials cell that are flat and that form a single layer of epithelial tissue. stratified tissues: Tissues that have multiple layers of the same cell type, such as is found in the skin. stratum basale: The innermost layer of the epidermis. stratum corneum: The outer layer of the epidermis, consisting mainly of dead or peeling cells. stratum spinosum: The second epidermal layer. telophase: The fifth stage of mitosis in the cell cycle, during which the chromatin decondenses from chromosomes back to ribbons. A new nuclear envelope and nucleoli appear, and spindles vanish. tissues: Groups of cells that work together for a common goal. The human body has four basic types of tissues: epithelial, connective, muscle, and nervous. transmembrane proteins: Proteins that span the width of the plasma membrane to transport nutrients and waste products into and out of the cell. Some transmembrane proteins contain channels through which certain ions and molecules can enter or leave the cell. vesicle: A small sac or cavity, especially one containing fluid. Student Projects • Create a visual representation of a cell, using the vocabulary section of this guide to label its components. This can be done as a large, colorful poster, or as a series of detailed blow-ups following an overview sketch. This project can also be done (perhaps by groups of students working together) as an illustrated “Guide to the Cell,” e.g., “Welcome to the cell! We hope you enjoyed your trip through the plasma membrane…. As you make your way around the cytoskeleton you’ll notice ...” The guide should include information on all the parts of the cell, and the jobs that each performs. Films for the Humanities & Sciences ® Copyright © 2009 Films for the Humanities & Sciences® • www.films.com • 1-800-257-5126 9 The Human Body: How It Works CELLS, TISSUES, AND SKIN INSTRUCTOR’S GUIDE • Organelles are critical to the functioning of the human body. Using information from this film and other sources, make a chart that lists important organelles, with columns for their function, appearance, and a “plain English” explanation of what they do. • Choose a process such as the cell cycle, or one of the types of active or passive transport, and explain it in detail to your classmates. Use visual aids (posters, drawings, Flash animation, PowerPoint, etc.) to help make complex information clear. • Visit “BioVisions,” a Web site created by Harvard University’s Department of Molecular and Cellular Biology, at http://multimedia.mcb.harvard.edu. Click on “The Inner Life 8 Min.” to watch their award-winning animation of what goes on inside a cell. Watch the clip with the sound turned off and see how many structures and processes you can identify. • Did you know that researchers are working to develop computers that process information using DNA instead of silicon chips? Scientists at Columbia University and the University of New Mexico have already created MAYA-II, a DNA computer that can play tic-tac-toe. Future DNA computers are expected to be able to hold billions of times more information than current devices, using a fraction of the space. The plan is to harness DNA computing for pharmaceutical and biomedical use. Using the Internet, see what you can find out about DNA computers and DNA nanotechnology, then create a report to present to the class. • Read some ads for skin creams, moisturizers, and anti-aging formulations. Do these really work as claimed, and if so, how? Can skin really be softened, collagen repaired, and wrinkles eradicated? Investigate the following additives to skin creams and report (in the form of a brief paper, or chart) on whether they harm, enhance, or have no known effect on skin: humectants or emollients; vitamins or anti-oxidants; herbs or plant extracts; mineral oil, sodium lauryl sulphate, or other additives; collagen or proteins. As you conduct research, be wary of cosmetics manufacturers’ Web sites masquerading as unbiased, “scientific” sources. As a related project, print out some of these ads to read and analyze with the rest of the class, taking note of vague language, uncited “studies,” and misleading use of scientific terms. • According to the National Cancer Institute, there were more than 1,000,000 new cases of nonmelanoma cancer in the U.S. in 2008, and more than 62,000 cases of more lethal forms of skin cancer. Do some research on the types of skin cancer, including risk factors, symptoms, and treatments. Present your information in the form of a journal or blog entry written by someone who has been diagnosed with a skin cancer. Include information on tanning beds and booths, exposure to sunlight, and “sunblock” formulations. Films for the Humanities & Sciences ® Copyright © 2009 Films for the Humanities & Sciences® • www.films.com • 1-800-257-5126 10 The Human Body: How It Works CELLS, TISSUES, AND SKIN INSTRUCTOR’S GUIDE Quiz 1. Which of the following is/are NOT a component of our cells? a) lignin b) plasma membrane c) organelles d) cytoplasm 2. Which statement most accurately describes the cell membrane? a) It is an impermeable but flexible “skin” that blocks harmful foreign particles from entering the cell. b) It is a semi-permeable membrane composed of cholesterol molecules. c) It is a semi-permeable membrane containing mechanisms that allow the cell to receive nutrients, dispose of waste, and recognize other cells as being “like them.” d) It is a complex membrane containing the genetic code to reproduce all other cells in the body. 3. Cells are able to renew their supply of oxygen through the process of _____. a) the cell cycle b) simple diffusion c) osmosis d) active transport 4. (Choose the correct term.) [Osmosis/Diffusion] is the movement of fluids through semi-permeable membranes, while [osmosis/diffusion] is the movement of particles, not necessarily across a membrane. 5. Exocytosis, by which the cell gets rid of waste, is an example of _____. a) an active transport process, meaning the cell must expend energy to get it done b) an active transport process, meaning the cell transports substances throughout the cell network c) a passive transport process, meaning the cell does not need to expend energy d) a simple transport process, meaning it involves a rudimentary function of cell metabolism Films for the Humanities & Sciencesi ® Copyright © 2009 Films for the Humanities & Sciences® • www.films.com • 1-800-257-5126 11 The Human Body: How It Works CELLS, TISSUES, AND SKIN INSTRUCTOR’S GUIDE 6. Match the organelle to its function(s). 1) endoplasmic reticulum 2) Golgi apparatus 3) mitochondrion a) called the “processing and transportation center” of the cell b) synthesizes proteins secreted from the cell c) connects with other organelles and the cell nucleus d) supplies the cell with ATP, the energy needed to perform its functions e) receives proteins, then packs them into vesicles f) manufactures certain lipid molecules g) called “the cell’s power plant” 7. True or False? The nucleus consists of a gel-like substance surrounded by an impenetrable membrane. Its main function is to process nutrients for the cell. 8. The purpose of the cell cycle is _____. a) to carry oxygen and nutrients to the cell and carbon dioxide and waste away from the cell b) to synthesize the body’s proteins c) the replication and active transport of the cell d) the growth, replication, and division of a cell, resulting in two new cells 9. Although there are several substages, the main stages of the cell cycle are ____. a) prophase (when the cell brings in nutrients) and mitosis (when the cell expels waste) b) interphase (when the cell grows and develops), prometaphase (when genetic material replicates), and metaphase (when the cell uses active transport) c) interphase (when the cell grows and develops), mitosis (when genetic material replicates), and the process of cytokinesis (when the cell actually divides into two new cells) d) prophase (when proteins are transported to the nucleus), mitosis (when proteins replicate), and cytokinesis (when proteins are actively synthesized) Films for the Humanities & Sciencesi ® Copyright © 2009 Films for the Humanities & Sciences® • www.films.com • 1-800-257-5126 12 The Human Body: How It Works CELLS, TISSUES, AND SKIN INSTRUCTOR’S GUIDE 10. Match the type of tissue to the appropriate phrase below. 1) epithelial 2) connective 3) muscle 4) nervous a) pumps blood b) fills spaces between cells and stores fat c) lines most internal cavities and organs d) the brain is this type of tissue e) covers body surfaces f) is the major component of glands g) involved with digestion h) blood and bone are this type of tissue i) the spinal cord and peripheral nerves are this kind of tissue j) further classified as skeletal, smooth, and cardiac k) protects against infection and helps repair tissue damage 11. Which of the statements below is false? a) The outermost layer of the skin consists of 20 to 30 rows of dead cells, which are constantly sloughing off and being replaced with new cells from the strata below. b) The skin synthesizes vitamins A and C in the presence of sunlight. c) The skin consists of two main layers — the epidermis and the dermis — with additional sublayers. d) Melanocytes — a type of epidermal cell — produce melanin, a pigment that influences skin color and protects against harmful ultraviolet radiation. Films for the Humanities & Sciencesi ® Copyright © 2009 Films for the Humanities & Sciences® • www.films.com • 1-800-257-5126 13 The Human Body: How It Works CELLS, TISSUES, AND SKIN INSTRUCTOR’S GUIDE Answers to Quiz 1. a) lignin 2. c) It is a semi-permeable membrane containing mechanisms that allow the cell to receive nutrients, dispose of waste, and recognize other cells as being “like them.” 3. b) simple diffusion 4. Osmosis; diffusion 5. a) an active transport process, meaning the cell must expend energy to get it done 6. 1) endoplasmic reticulum b) synthesizes proteins secreted from the cell c) connects with other organelles and the cell nucleus f) manufactures certain lipid molecules 2) Golgi apparatus a) called the “processing and transportation center” of the cell e) receives proteins, then packs them into vesicles 3) mitochondrion d) supplies the cell with ATP, the energy needed to perform its functions g) called “the cell’s power plant” 7. False. The nucleus consists of nucleoplasm, which contains the nuclear lamina, nucleoli, chromatin, DNA, and RNA; the membrane surrounding the nucleus — the nuclear envelope — contains nuclear pores through which nutrients can pass. The main function of the nucleus is to direct the activity of the cell and to mediate the replication of DNA during the cell cycle. 8. d) the growth, replication, and division of a cell, resulting in two new cells 9. c) interphase (when the cell grows and develops), mitosis (when genetic material replicates), and the process of cytokinesis (when the cell actually divides into two new cells). Films for the Humanities & Sciencesi ® Copyright © 2009 Films for the Humanities & Sciences® • www.films.com • 1-800-257-5126 14 The Human Body: How It Works CELLS, TISSUES, AND SKIN INSTRUCTOR’S GUIDE 10. 1) epithelial c) lines most internal cavities and organs e) covers body surfaces f) is the major component of glands 2) connective b) fills spaces between cells and stores fat h) blood and bone are this type of tissue k) protects against infection and helps repair tissue damage 3) muscle a) pumps blood g) involved with digestion j) further classified as skeletal, smooth, and cardiac 4) nervous d) the brain is this type of tissue i) the spinal cord and peripheral nerves are this kind of tissue 11. b) The skin synthesizes vitamins A and C in the presence of sunlight. Please send comments, questions, and suggestions to [email protected] Films for the Humanities & Sciencesi ® Copyright © 2009 Films for the Humanities & Sciences® • www.films.com • 1-800-257-5126 15