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BIO 156 L AB 15: H ISTOLOGY - A SURVEY OF HUMAN T ISSUES
READINGS: Campbell, Mitchell & Reece, Customized Biology: Ch. 20 Perry/Morton Photo Atlas pg. 9-29 (each is referenced below with PM and the page number) MULTIMEDIA SUPPORT AND MATERIALS IN THE LAB: (Check out videos from Lab Staff or tutors) CMR Interactive Study Partner CD – ISP – Ch. 20 Bio 156 Epithelium, CT, Muscle and Nerve tissue 35 mm slide carousels of examples of these tissues: use the list that tells you the name of the slide in each slot of the carousel. Tissue posters on the back wall; these also contain excellent examples Anatomy & Physiology Videodisk Ch. 4 with alphabetical index or frame index SUGGESTED WEB SITES: http://www.kumc.edu/instruction/medicine/anatomy/histoweb (an excellent site: has descriptions and photomicrographs of all tissue types) http://www.cord.edu/faculty/todt/336/lab (contains slides at different magnifications - some have labels) http://www.cbu.edu/~aross/histol.htm (also contains links to lots of other histology sites) www.meddean.luc.edu/lumen/MedEd/Histo/frames/histo_frames.html (Loyola University Cell and Molecular Biology - includes "lab practicals" for self quizzing) http://www.cedarville.edu/dept/sm/sullivan/histology (includes great labeled diagrams and a fun "histo-Hangman" game to review vocab!) *NOTE: You might consider purchasing the text that you will be using in Bio 201/202 at this point. Chapter 4 in the Anatomy and Physiology book provides a more thorough discussion of tissues than your text does. This text is also on reserve in the library, should you wish to make a copy of chapter 4 to use as an additional reference.
Loose Connective Tissue Proper
Simple Cuboidal Epithelium
Bone
Cardiac Muscle
A Neuron
OBJECTIVES: Explain the relationship between tissues and the other levels of organization: atoms, molecules, cells, organs and organ systems. Define the terms and cell types listed in bold in this lab. Identify each of the selected tissues in the microscope. Describe the structure and function of each of these selected tissues. List at least one place in the human body where each of these tissues can be found.
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NAME ________________________________CLASS ________________________________ BACKGROUND: AN INTRODUCTION TO HUMAN TISSUES A challenge for many biology students is developing a clear understanding of the levels of organization – the description of what biological parts are composed of which other parts (sec. 20.2). As you have learned in previous sections of this course, atoms are the smallest building blocks of all matter. Both life and non-life are also composed of bonded atoms – molecules. Cells, the smallest units of life, contain organelles, which are, in turn, built of molecules. In the Biology 156/201/202 sequence, you will study the human organism by examining its parts, and the parts of its parts. From simplest (smallest) to most complex in a single organism they are: atoms molecules cellular organelles cells tissues organs organ systems Higher levels of organization exist as well. These levels describe groups of organisms of the same or different species (populations and communities, respectively), and the interactions between living and non-living components at the ecosystem level. The organ systems and most of the organs that comprise them are visible with the naked eye, and thus easier to visualize and understand than the cell and molecular levels of organization. You know, for example, the trachea and lungs are organs found in your respiratory system, while the esophagus, stomach and intestines are parts of your digestive system. A list that includes some of the major organs found in and the general functions of each of the organ systems in the human body appears below:
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NAME ________________________________CLASS ________________________________ You have completed an introduction to cells, and so this level, though microscopic, should be somewhat familiar as well. In this lab, we explore the link between the two: the tissue level of organization. Tissues are groups of cells and intercellular materials that have a similar developmental origin, structure and function (sec. 20.3). All organs are composed of at least two different tissues (sec. 20.8), so as we continue to explore body systems, you will review the tissues described in this lab. The study of tissues is called histology. There are four primary types of tissues (epithelium, connective tissue, muscle and nerve) that are found in the human body; each has sub-categories. Each of these four types is described in detail in this histology lab. By the date of the lab exam, you must know the structure (S) and function (F) of each type, and understand where in the body it is likely to be found (E). The descriptions in the lab also include, where appropriate, special information or issues (I) that relate only to that tissue type. Your instructor will demonstrate each of these tissues using the 35 mm slides in the carousels and/or videodisk images to help you become familiar with their unique, identifying characteristics. You will then view glass slides of the tissues using your own microscope. Your lab task is simply to review the glass slides again and again until you can name the tissue as you see it in a microscope. However, it’s critical to know what you are looking for before you attempt to view these slides in your microscope. Begin by opening your Photo Atlas to the
correct photomicrograph listed with each tissue demonstration. Read the description of the tissue in this lab and your text, and find the important regions or identifiers by attending to the labels in the photomicrographs in the Atlas and on the posters on the wall. It is best to do this activity with your partner; one of you might recognize an important feature or method of identifying the tissue that the other does not! Remember that your textbook’s information is not as thorough as that in an anatomy and physiology text, and so some of the required tissues described in this lab are not found in your text. Therefore, it will be important to refer to other sources to develop a complete understanding of histology. Consistent recognition of the slides will require repeated viewing, so you are encouraged to spend extra time with the glass slides and other support materials outside of class sessions. See the tutor or our science technicians to check out a microscope, the 35 mm projector and slides.
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NAME ________________________________CLASS ________________________________ Each slide box contains specific types of tissue slides. Please check the handout and determine which slides you wish to look at. Take one slide at a time and return it to the box from which it came. (Please check the lid of the box to make sure you are putting it away correctly!) Remember to follow the appropriate storage and care restrictions whenever you use a microscope!
EPITHELIUM (S) Epithelial tissue is any tissue that lines or covers body cavities, surfaces, tubes or glands (sec. 20.4). Epithelium may be single- or multi-layered, and the cell shapes in the different subtypes vary (see summary figure on page 6). All epithelium: is avascular – it does not contain blood vessels, which means that epithelium does not contain a direct supply of nutrients and oxygen; it may, however, contain nerve endings (it may be innervated) and so may be directly capable of sensation. (Note: in some cases, the nerve endings are in other tissues below the epithelium.) consists of closely packed cells with specialized junctions. is formed of cells that have two distinct surfaces: the side of an epithelial cell next to the open space or surface is called the apical side, and the surface that is next to cells of a different tissue type is termed the basement side (see figures on the next page); the layer underneath the basement side of the epithelium is typically connective tissue, and since connective tissue (CT) usually contains blood vessels, the CT is typically the source of food and oxygen for the epithelial cells. the basement membrane, a matrix of polysaccharides and proteins underneath the basement cells of the epithelial layer, is secreted by both the epithelium and connective tissue under it; this layer (which is not a phospholipid bilayer) attaches the epithelium to the tissue underneath it (usually connective tissue). is made of cells that have a high regenerative capacity (i.e., they divide frequently by mitosis to replace dead cells); this feature ensures that epithelial tissue readily heals itself. (F) The functions of epithelial tissue depend on the number of layers and types of cells in the particular tissue. They include covering, protecting, allowing for exchange, secretion, and sensation. Some epithelial cells have surface modifications on the apical side of epithelial
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NAME ________________________________CLASS ________________________________ cells that face a lumen (the inside of a tube) which allow for special functions. For example, the apical surface of intestinal epithelial cells contain microvilli – microscopic foldings of the epithelial membrane – that increase surface area and thus increase the ability of these cells to absorb materials. Cilia – tiny hair-like structures on the apical side of respiratory cells – create a current that helps propel mucus. (I) Epithelial tissue names include a description of the number of cell layers and the shape of the cells at the side of the tissue facing a lumen or outer surface. Section 20.4 in your text has diagrams of some of these types. The figure below demonstrates that epithelium composed of a single layer of cells is called simple epithelium, while multiple-layered epithelium is stratified. One type of epithelium has only a single layer of cells, but the varied shape of the cells makes it appear on first glance to be multi-layered. Since this epithelium appears multi-layered but is not, it is said to be pseudostratified (“falsely stratified”) epithelium. Epithelial Layers Epithelial Cell Types
Epithelial cells at the surface of the tissue take on the three characteristic shapes shown on the right side of the above figure. Squamous cells are flattened like pancakes or scales. They have a central nucleus and look like a mosaic from the surface. The cheek cells that you observed in the cell lab are squamous cells. Cuboidal cells are roughly cube-shaped in cross section and also have a central nucleus. Columnar cells are so named because they are long and tall (column-shaped) in cross section; their nuclei are
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NAME ________________________________CLASS ________________________________ usually found near the basement side of the cells. In stratified epithelium, the cells bordering the basement membrane may be differently-shaped than those on the lumen or surface side; it is always the shape of the cells bordering the space that is used to name the tissue. Summary diagram of some of the epithelial tissue types:
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NAME ________________________________CLASS ________________________________ Listed below and on the following pages are the names, structures and functions of most of the types of epithelium found in the human body. (Some rare types such as stratified cuboidal epithelium have been eliminated). Remember that you will be asked to recognize each of these types for the exam, and will need to identify at least one place in the body where each can be found, as well as any special information that is relevant to the tissue type.
Simple Epithelium: (single layered for areas of minimal wear and tear) Simple Squamous Epithlium (Sec. 20.4a, PM 9e, Cheek smear stained with methylene blue, A&P Box 4 Frog Skin, Carousel 3 spaces 1 - 5, poster): S: is composed of a single layer of flattened cells. F: ideal for transport (diffusion, filtration, osmosis) into underlying tissue layers since the layer is so thin. E: is found lining lung cavities, glomerulus and Bowman's capsule in the kidney, and capillary walls – all sites of transport. I: Epithelium lining the heart and blood and lymph vessels is called endothelium; epithelium lining serous membranes (membranes of body cavities that do not open to the outside) is called mesothelium.
Simple Cuboidal Epithelium (Sec. 20.4b, PM 9f, A&P Box 3 Simple Cuboidal, Carousel 3 spaces 7 & 8, poster,): S: is composed of a single layer of cube-shaped cells. F: provides a thin lining layer that often functions in secretion (exocytosis of materials built by the cell) and absorption (diffusion of soluble substances) into underlying tissues. E: is found on the ovarian surface, as part of eye lens and retina, lining kidney tubules (with microvilli for increased absorption), and in portions of small glands.
Simple Columnar Epithelium (Sec 20.4c, PM 10a, A&P Box 3 Simple Columnar, Carousel 3 spaces 10 - 12, poster): S: is composed of a single layer of tall, long cells with basal, oval nuclei; some cells have cilia or microvilli at their apical surface; some simple columnar epithelium contains interspersed goblet (mucus-secreting) cells.
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NAME ________________________________CLASS ________________________________ Simple Columnar Epithelium cont. F: is thicker than squamous and cuboidal epithelium, so it provides some protection; surface modifications (cilia and microvilli), if present, allow for movement of material and improved absorption; if goblet cells are present, the mucus may trap materials (e.g., in the respiratory tract) or facilitate movement through the system (e.g., in digestion). E: is found lining the gastrointestinal (GI) tract (upper intestine has microvilli), gall bladder, excretory ducts of glands, upper respiratory tract (this region is ciliated), uterine tubes and some regions of the uterus, and the central canal of spinal cord.
Pseudostratified Columnar Epithelium (not in text, PM 10b, A&P Box 3 Pseudostratified ciliated columnar, Carousel 3 spaces 14 & 15, poster): S: is composed of one layer of cells, but not all of the cells reach from basement membrane to lumen; the nuclei are found at different levels and thus give the appearance that the tissue is multilayered, but it is not; goblet cells may be interspersed, and cilia may be found on the apical surface. F: like columnar epithelium, this tissue is somewhat thick, and so provides a small amount of protection; it may also function in secretion; if cilia are present, movement through the system is facilitated. E: can be found lining the excretory ducts of many glands, parts of male urethra, and the auditory tubes; the trachea and most of the upper respiratory tract are lined with ciliated pseudostratified columnar epithelium.
Stratified Epithelium: multiple layers are useful for areas of high wear and tear; fast replacement of damaged tissue; remember that the name depends on the type of cell at the surface or lumen side Stratified Squamous Epithelium (Sec. 20.4d, PM 10d and 11a, A&P Box 3 Stratified Squamous, Carousel 3 spaces 17 - 22, A&P Box 4 Skin, Skin with hair Explanomounts, poster): S: is multilayered, with flattened cells at surface (apical) side; cells next to the basement membrane are often cuboidal/columnar in shape; since the upper cells are far from the blood supply in the underlying CT, they do not receive nutrients and oxygen and
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NAME ________________________________CLASS ________________________________ dehydrate (shrink and harden) and die; the rapid mitotic rate of the basal cells pushes new cells out to replace the dead cells that fall off; in skin, surface cells are filled with the protein keratin that is waterproof and friction-resistant (PM 11.d and skin slides). F: the multiple layers make this tissue ideal for protection (keratinized cells provide extra protection). E: is often found covering or lining where high wear-and-tear is expected; the upper GI tract, female urethra and vagina are lined with non-keratinezed stratified squamous epithelium; skin is keratinized.
Stratified Cuboidal Epithelium (not in text, PM 10c, no glass slide): S: is composed of two (or more) layers of cubes; is rare. F: provides a small degree of protection due to the multiple layers. E: is found in large sweat gland ducts, eye fornix, male urethra, mammary glands, salivary glands.
Stratified Columnar Epithelium (not in text, not in PM, no glass slide) S: is multilayered with columnar cells at lumen/surface; polyhedral cells underlie the apical cells; is also rare. F: functions in protection and secretion. E: is found in male urethra, large excretory ducts of some glands, small areas of anal mucous membrane.
Transitional Epithelium (not in text, PM 11 b & c, A&P Box 3 Transitional, Carousel 3 spaces 24 & 25, poster): S: looks similar to nonkeratinized, stratified squamous with outer layer of large and rounded cells (structure of surface cells varies with degree of organ stretch). F: is distendable and stretchy, for lining areas that expand (when the cells are stretched, the surface cells lose their cuboidal appearance and look more like squamous cells). E: is found in the urinary bladder, ureters and urethra and parts of uterus.
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NAME ________________________________CLASS ________________________________
Glandular Epithelium A gland is group of cells or a single cell (e.g. a goblet cell) that secrete (produce and release) a specific product. Often, multi-cellular glands are composed of clusters of cells that are deep to the covering epithelium (i.e., part of the gland is often in the connective tissue). If the gland releases its product to the surface the epithelium covers (e.g., a sweat gland) or to the lumen the epithelium lines (e.g., a gland producing digestive enzymes), ducts carry the products from the base of the gland to the opening. Glands that secrete their products into ducts/tubes that empty at surface/lumen are called exocrine glands. Endocrine glands secrete their products (typically hormones) into the blood stream; these hormones then regulate body functions. The pituitary, thyroid, parathyroid, adrenals, ovaries and testes, and thymus glands are examples of endocrine glands.CONNECTIVE TISSUE = CT There are many types of connective tissue (sec. 20.5) ranging from the material that literally connects your muscles to your bones (your tendons), to blood and bone that do not connect one part to the other in the formal sense. The figure below shows some of the more prevalent subtypes found in the connective tissue category.
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These tissues are grouped together because of their similar developmental origin. The subtypes also share many structural features. The figure on the next page identifies the primary types of connective tissue, and shows their shared developmental origin. Note that they are all derived from an embryonic tissue called mesenchyme. After mesenchyme cells divide in the fetus, they differentiate by turning on selected genes and producing the proteins that allow these cells to take on their unique functions.
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(S) Unlike epithelium, most connective tissue is highly vascular (i.e., there are many blood vessels found in the tissue). Recall that the blood in the connective tissue is the source of the food and oxygen for the epithelium above it. There is, however, a range of vascularity in the different connective tissues. Cartilage, for example, contains no blood vessels, but loose connective tissue proper is highly vascular. The prevalence of blood is correlated to the ability of the connective tissue to heal itself when injured. Unlike epithelium, connective tissue is typically composed of scattered cells plus a lot of cellularly-produced matrix or ground substance. The molecular matrix surrounding the cells determines the specific structure and function of the tissue, so you must know the names and qualities of the cells and of the matrix in each type of connective tissue. Blood matrix (plasma), for example, is fluid and designed to carry dissolved molecules, while calcium and proteins found in your bone matrix results in their hardness. Different fibers give connective tissue types unique properties as well.
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NAME ________________________________CLASS ________________________________ (F) Connective tissues (CT) have many different functions including protecting, supporting, binding, separating, storing energy reserves, and transporting materials. As with epithelium, it is most important to understand the function of each of the sub-categories. (I) All connective tissues are derived from the same embryonic tissue; all have some type of matrix, cells and fibers. The matrix or ground substance is non-cellular. It fills the spaces between the cells and contains fibers, fluid and dissolved molecules. The cells secrete matrix and are living component of connective tissues. They are active especially in repair of damaged CT. Learning the following consistent prefixes and suffixes will help you identify the cell types of each CT: -blast = precursor cell -cyte = fully formed and functional cell -clast = destructive cell adipo = fat chondro - cartilage osteo = bone fibro = fiber So, for example, an osteoblast is a cell that is destined to become a bone cell, and a chondrocyte is a mature cartilage cell. A fibroblast is a cell that produces fibers. There are three important types of fibers typically found in CT matrix. Collagenous (white fibers) occur in bundles of parallel minute fibrils made of protein collagen. These fibers are resistant to stretching and thus provide high tensile strength. They are somewhat flexible. Your tendons and ligaments are composed primarily of collagenous fibers. Elastic (yellow fibers) are thinner than collagenous fibers and are often branch. They are composed of the protein elastin, which provides some strength and great elasticity. Reticular fibers are thin/fine and form branching networks like webs that give some support and structure to many soft organs such as your liver or kidneys.The figure below of areolar connective tissue (which is also called loose connective tissue proper) serves as a model for the basic structure of connective tissues. Multiple types of fibers and cells are surrounded by a ground substance or matrix.
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Embryonic CT/mesenchyme is found primarily in the fetus; differentiation of these cells gives rise to all the types found in the adult (not in text, PM 12a, Carousel 1 spaces 1 - 4, Box 10 CT Dev - mesenchyme sec): Mesenchyme: S: the cells are highly branched and star-shaped; the matrix is fluid (this tissue lacks the unique, defining characteristics of other CT types such as cartilage, bone or blood). F: is the precursor of all other CT types; it also produces fibroblasts for healing. E: is present under the skin and along the developing bones in the fetus; in the adult, it is present in other CT. Mucous CT (Wharton's jelly): S: the cells are flattened or spindle shaped; the matrix is mucus-like with fine collagenous fibers.
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NAME ________________________________CLASS ________________________________ F: supports wall of umbilical cord. S: is found only in the fetal umbilical cord. Adult Connective Tissues: The following types of CT (areolar, adipose, fibrous and reticular CT) are all grouped into a general category called Connective Tissue Proper. In these cases, the fibroblast cells that produce the matrix and fibers found in the matrix are large & flat with branching processes. The matrix is mostly fluid. These CT all differentiated from mesenchyme CT; the cells do not dedifferentiate after birth.
Loose CT Proper = Areolar CT Proper (Sec. 20.5a, PM 12b, Box 7 Areolar tissue spread film/ sec, Carousel 1 spaces 6 - 8, poster): S: the cells are scattered fibroblasts; some blood cells (macrophages; mast cells) will be found in vessels in the matrix or moving directly though the matrix; the matrix is a viscous fluid with loose network of collagenous and elastic fibers. F: attaches the skin to underlying muscles, supports internal organs, blood vessels and nerves, and wraps and cushions organs; white blood cells (WBC) like macrophages in the matrix phagocytize bacteria; the collagenous fibers are hydrophilic, so this tissue also functions as a water/salt reservoir. L: is found under the epithelium in “skin”, and around organs and capillaries.
Reticular CT (CT Proper) (not in text, PM 14b - d, Carousel 1 space 18, poster) S: the reticular cells are found in a web-like network of reticular fibers; the loose matrix is similar to that of areolar CT. F: provides a soft, internal “skeleton”-like structure to support other cells such as blood cells. L: is found in lymphoid organs (lymph nodes, bone marrow, spleen). Adipose (CT Proper) (Sec. 20.5b, PM 13c - e, Box 7 Adipose tissue, Brown Adipose, Carousel 1 spaces 20 - 22, poster): S: fat cells (adipocytes) contain triglyceride molecules in a large, central vacuole; the cells are closely packed so there is little matrix, but what’s there is similar to that of areolar CT; this tissue is highly vascular (since blood brings fat molecules to and from the cells).
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NAME ________________________________CLASS ________________________________ F: stores excess nutrients as fat, cushions internal organs, and insulates the body for warmth. L: is found under the skin, around some organs, in bones (esp. of an adult), and in breasts. Dense, Regular/Fibrous CT Proper (Sec. 20.5d, PM 12d, Box 7 tendon teased, white fibrous CT ls, muscle tendon connection, Carousel 1 spaces 10 - 11, poster): S: the fibroblast cells are tightly packed in rows between parallel bundles of collagenous fibers (look for difference in nuclei vs. smooth muscle – collagenous fibers are not cells and do not have nuclei, so you’ll only see nuclei between the fibers here); there is little matrix; the tissue is poorly vascularized (so it doesn’t heal quickly). F: provides a strong attachment of bones to muscles, bones to bones, and muscles to muscles; this tissue withstands great tensile stress in one direction. L: is found in tendons, ligaments, and aponeuroses (flattened sheets of CT on the skull). Dense, Irregular CT Proper (not in text, PM 12, Box 5, 6 Skin slides (under the stratified squamous epithelium, Carousel 1 spaces 17 - 22): S: like dense, regular CT, there are tightly-packed fibroblast cells and fibers with little matrix; the collagenous fibers, however, are irregularly arranged. F: withstands stress in many directions (vs. dense regular CT proper, that withstands stress in one direction) L: is found in the dermis (deep layer) of the skin and in fibrous capsules around many organs and joints Elastic CT Proper (not in text, PM 13a,b Box 12 Artery and Vein cs, Carousel 1 spaces 13 16): S: contains fibroblasts that produce elastic fibers as well as collagenous fibers; the matrix is similar to that of dense, regular and dense irregular CT. F: the elastic fibers provide additional durability and stretch to the tissue. L: is found in the aorta wall, walls of other large arteries, parts of trachea and bronchi, vocal cords, and ligaments which connect vertebrae.Adult Connective Tissues cont.: due to their unique matrix and/or cell qualities, these are not grouped into the CT Proper sub-category. Cartilage (Connective Tissue) (Sec. 20.5e, PM 15a, b, A&P Box 5, Hyaline cart. H&E and trachea, Carousel 1 spaces 24 - 27, poster): S: all cartilage types contain chondrocytes (mature cartilage cells) found lacunae (holes); as the chrondrocytes mature, they secrete a firm, homogeneous, gel-like (bluish-white)
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NAME ________________________________CLASS ________________________________ matrix with “invisible” collagen fibers around themselves, which results in the final placement in the lacuna. Hyaline cartilage matrix appears blue and glassy. Elastic cartilage contains black, branching elastic fibers in the matrix. Extra collagenous and elastic fibers in fibrocartilage can be seen with special stains; a piece of fibrocartilage has the consistency of a car tire. F: Hyaline cartilage protects bones at joints, attaches the ribs to the sternum, forms part of the nose and supports the walls of air passages (it holds the airway open) and provides a pattern for bone development in the fetus; the support and protection in these areas is due to the resilient cushioning provided by the collagen. Elastic cartilage provides some support and structure but is very flexible. Fibrocartilage is very strong and somewhat flexible and so acts as a protective shock absorber. I: Hyaline cartilage is found at the tip of your nose, between the bones of many of your joints, in the walls of your trachea; it also comprises the embryonic skeleton and epiphyseal plates (bone replaces cartilage in development and in long bone growth). Elastic cartilage is found in the external ear (consider how it provides a flexible shape to this area) and epiglottis. Fibrocartilage composes the intervertebral disks (the disks between the vertebrae in your spine), and forms the cartilagenous pads in the knee joint and the cushion between the symphysis pubis.
Bone (Connective Tissue) (Sec. 20.5f, PM 16 a - d, A&P Box 6 Bone, dry ground human cs, Carousel 1 spaces 41 - 50, 2 posters). Identify Compact Bone only (You will examine bone in more depth with the skeletal system in Bio 201): S: Osteocyte cells are found in lacunae, as chondrocytes are in cartilage; canaliculi (tiny canals that extend from the lacunae) contain the osteocyte processes and allow the cells to "feed" from the blood; the matrix is composed of hard calcium phosphate which is deposited on proteins in lamellae (rings); a central Haversian canal contains blood vessels and nerves; a set of lamellae etc. is called a Haversian system. F: Compact bone forms the sides and surfaces of the skeleton that provides support for the body and protection for vital organs, and allows for movement when connected to muscle; blood develops in hollow cavities within bones and in smaller spaces between
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NAME ________________________________CLASS ________________________________ the spongy bone process that are found in your flat bones and at the ends of your long bones.
Blood (Connective Tissue) (Sec. 20.5c, PM 93 a - g, A&P Box 8 Blood smear Wright (also Giesma stain and with arteries and veins on the artery/vein slide), Carousel 1 spaces 52 - 60, 2 posters. (You will study blood in depth with the cardiovascular system in Bio 201.): S: There are three categories of blood cells: the numerous red blood cells are flattened with a thinner center than edge and have no nuclei; these cells carry oxygen. White blood cells are rarer and have differently-shaped nuclei; these cells comprise part of your infection/disease fighting system. Platelets are small cell “chips” (they do not have a nucleus) which function in clotting. Blood plasma is the fluid matrix of this connective tissues. Dissolved nutrients, wastes, gasses, clotting proteins, and hormones are found in the plasma. F: Blood carries materials/information throughout the body and helps prevent many diseases. Small injuries to blood vessels are often healed due to the action of blood platelets.
MUSCLE This section provides a brief introduction to the three types of muscle: skeletal, cardiac and smooth muscle (sec. 20.6). A diagram below shows the identifying structural variations in the cells of the three important muscle types, and demonstrates where they can be found.
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You will study muscle tissues in greater detail in Bio 201, so this section is relatively brief. There are chapters devoted to studying skeletal muscle structure and function, and the cardiovascular system chapter contains a detailed discussion of heart (cardiac) muscle structure and function. Smooth muscle is reviewed in many systems such as the digestive system in Bio 202.:(S) Muscle tissue is the only tissue in your body that is contractile (it can shorten on demand). Contraction occurs when proteins (actin and myosin) within muscle cells grab on to each other and pull together in a process that requires a significant energy expenditure. Thus muscle cells must produce a lot of ATP to power this work. ( What ATPproducing organelle is likely to be found in high numbers in muscle cells?) Muscle cells
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NAME ________________________________CLASS ________________________________ have lost the ability to divide, but will add contractile proteins and thus become thicker cells when demand increases. (F) Muscle tissues do many different types of work. Skeletal muscles allow for movement and support. Shivering (rapid contraction of these muscles) produces heat for temperature
regulation. Cardiac muscle in your beating heart ensures that blood will be transported throughout the body. Smooth muscle contracting in the walls of your esophagus and
intestine moves food through your gastro-intestinal tract.
Skeletal Muscle (Sec. 20.6a, PM 20 a-c, 21 a-c, A&P Box 9 Muscle composite, teased skeletal, muscle tendon connection, Carousel 2 spaces 1 - 10, poster). S: Skeletal muscle is any muscle attached to a bone. Skeletal muscle cells are crossed with striations (alternating dark and light bands - see sarcomere structure in model); unlike other cells, they have peripheral, multiple nuclei. F: Skeletal muscle contraction is voluntary and fast to moves bones/body
Cardiac (Sec. 20.6b., PM 22 a-b, A&P Box 9 Muscle composite, intercalated disks heart; 35mm space 42, 43, 44, 45; Carousel 2 spaces 12 - 17, poster S: in the heart; looks similar to skeletal (it's striated), but has intercalated disks between the cells; each cell has a single, central nucleus F: heart muscle contraction; involuntary, rhythmic contractions (circulation)
Smooth Sec. 20.6c, PM 22 c-e, A&P Box 9 Muscle composite, smooth muscle cs and ls; 35mm space 40, 41; Carousel 2 spaces 19 - 21, poster). S: cells are elongated, tapered, non-striated with a single, central nucleus; lines GI tract and other hollow, internal organs and blood vessels F: involuntary, slow contraction NERVOUS You'll study nervous tissue in depth when you focus on the nervous system in Bio 201, so this section is also brief. (S) Nerves are bundles of nerve cells (neurons) along with surrounding cells (neuroglia) that perform a variety of tasks that facilitate the functioning of the entire body. We’ll focus today
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NAME ________________________________CLASS ________________________________ on the structure and function of a single neuron (see fig 3.20). Nerve cells typically contain three important regions. The cell body contains the nucleus and many of the organelles (e.g., SER and RER, mitochondria). Two types of long, thin processes extend from the cell body. Two types of processes extend from the cell body. Dendrites receive information from the outside world (e.g., in sensory neurons) or from other neurons. Most neurons have
multiple dendrites. A typical neuron contains a single axon that transmits a signal (an action potential) down its length. When the action potential reaches the end of the axon, neurotransmitters are released from the ends of the axon; these molecules transmit the signal to the next neuron, muscle or gland. This
connection with the next cell is called a The processes identified in the figure below synapse. In sum, the signal travels from the are either axons or dendrites. Though these end of the dendrite to the cell body and down processes carry information in different the axon to a synapse with the next cell in line.
directions, they are indistinguishable in slides.
(F) Nerve tissue is excitable: electrical signals travel along neurons, and these signals are transmitted to other neurons or effector organs (muscles, glands) via chemical signals to allow for sensation, rapid transmission of information, stimulation of muscle cells that initiates their contraction, and storage of information.
Neurons: (Sec. 20.7)., PM 24 a-c, 25 a-c, 26c, 28d, Neuron models, A&P Box 10 Giant multipolar neurons, motor nerve ending, cerebral cortex and cerebellum; 35mm space 47, 48, 49, 50; Carousel 4, poster) For the lab exam, be able to identify the parts of a “generic neuron”; focus on slides or perkinje cells, giant, multipolar neurons and motor neurons.
J. Fiello; DVC Biology
2003/2004
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