BIO210 Weekly Guide #2   TISSUE TYPES; CONNECTIVE TISSUE  PROPER; DIFFUSION
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After completing this laboratory you should be able to:   1)   Recognize in slides or photomicrographs representative samples of the four basic tissue types found in the body   2)   Know the distinguishing anatomical and functional properties of each of the four basic tissue types   3)   List and describe the characteristic features and rules for naming connective tissue proper   4)   Recognize in microscope slides, correctly label, and describe the major properties and locations of the major types of connective tissue proper.   5)  Describe the processes of diffusion through an open medium and through a barrier membrane   6)  Understand and be able to apply Fick's Laws to predict relative diffusion rates and approximate diffusion times   7)  Describe the process and cellular consequences of osmosis through a semi-permeable membrane   8)  Define and correctly apply the terms permeable, permeant, impermeable, impermeant, hypoosmotic, isoosmotic, hyperosmotic, hypotonic, isotonic, hypertonic, diffusion coefficient, partition coefficient.                                                                   Gross Anatomy List Guide to Gross Anatomy Guide to Histology Guide to Physiology   Outline   I. Histology {FAP Ch 4; APL Unit 5 Prelab, Exercises 5.2 - 5.4}          A. Four basic tissue types - general properties and functions                epithelium                          lines surfaces, folded into glands                     polarity - apical and basal surfaces, basement membrane                     avascular                     classification - cell types, layers, surface modifications, accessory cells                connective tissue                     support, transportation, storage, defense                     cells and extracellular matrix                     vascular                     classification - fiber density and arrangement, fiber types, special types                muscle                     excitability and contractility                     cellular, syncytial                     vascular                     classification - skeletal, cardiac, smooth                nervous tissue                     excitabiltiy                     cellular - neurons vs. neuroglia                     vascular                     classification - gray vs. white matter, local structural organization          B. Connective Tissue  {FAP 4.4; APL Unit 5 Prelab, Exercise 5.2}             1. Properties                  cellular and extracellular components                  vascular (except cartilage & blood)                  mesodermal origin           2. Locations                  all over - especially bones, cartilaginous structures, ligaments,                  skin (dermis),  subcutaneous and deep fascia, organ capsules, blood           3.  Functions                  support                  exchange of metabolites                  storage                  defense           4. Types                  C.T. Proper                  bone                  cartilage                  blood          C. C.T. Proper {FAP 4.4; APL Unit 5 Prelab, Exercise 5.2}             1. Constituents                  cell types and functions                       fibrocytes (<--fibroblasts)                       macrophages (<--monocytes)                       mast cells                       plasma cells (<--B lymphocytes)                       fat cells                       transients (e.g. leukocytes)                  fiber types and properties                       collagenous                       elastic                       reticular                  ground substance            2. Types of C.T. Proper - properties and locations                  loose (areolar)                  dense                       regular                               collagenous vs. elastic                       irregular                  special                       adipose                       reticular                       pigmented                       mesenchyme & mucous (embryological)     II. Diffusion  {FAP 3.5; APL Exercise 4.2}          A. Definition - movement of dissolved particles through a medium or across a barrier              solvents, solutes, and solutions             concentration gradients             flux             what drives diffusion          B. Diffusion through a medium             Fick's Formula for Diffusion:                                 J = dQs /dt = DA(dCs/dx)                       (units for J are moles/cm2sec)                       the diffusion coefficient D                       dependent on temperature, independent of particle size in aqueous solutions                       approximate physiological rate of diffusion :   Z                            t in seconds = (distance in cm)2/D                             For aqueous solutions D = 10-5cm2/sec                       C. Diffusionacross a barrier             Fick's Formula for Diffusion:                 J = r (C1-C2)    (units for J are moles/cm2sec) ("r" = "rho")                 r  = DmK/x    (units for r are cm/sec)   ("r" = "rho")                         the permeability r ("r" = "rho")                       the partition coefficient for solutes     II. Osmosis, Osmoticity, Tonicity {FAP 3.5; APL Exercise 4.3}          A. Osmosis              thought experiment               osmotic pressure vs. hydrostatic pressure              consequences for living cells            B. Osmoticity and Tonicity - hypo, iso, hyper              definitions              for solutions of impermeant particles              for solutions of permeant particles          back to top=   Gross Anatomy List   There is no real gross anatomy this week, other than knowing locations for the various types of C.T. proper.            back to top=   Guide to Gross Anatomy   Anatomical Terms                                                                                                                Review anatomical terms, locations, planes, directions, regions, and motions from last week.  Practie these on your body, on the whole body and torso models, and on the skeletons and skeletal models.  Note:  USE EXTREME CARE AND LIMIT THE RANGE OF BENDING WHEN WORKING WITH THE JOINT MODELS.   back to top=   Guide to Histology   Getting Started   Demonstration slides will be set up for each topic. These slides will be taken from one of the four "Vertebrate Histology" loan collection boxes, which are available for you to use at any time.    To get started this week do the following:   1)   If necessary, review the "Care and Use of the Microscope" sections on the lab guide homepage of this manual.   2)   Work through this week's histology demonstration scopes, paying particular attention to identifying the bold terms on the accompanying cards.  You can use the figures as an additional guide.  As you develop questions, discuss them with the other members of the class, or ask the instructor.   3)  APL Unit 5 has worksheet questions and a pictorial guide to the histology of primary tissue types.    The Four Primary Tissues   With a few exceptions, every cell in the body may be classified as lying within one of four primary tissue types:   1)    epithelium 2)    connective tissue 3)    muscle 4)    nervous tissue   Work through the samples on display.  These four primary tissue types are so widespread and so important that we will be spending one or more weeks on each.  Each organ system includes many or all of these four tissue types, and the knowledge and skill that you build in the early weeks will be extremely helpful later in the course.   Basic Tissue Types:       epithelium:                                                    connective tissue:          lines surfaces, folded into glands                    support, storage, transport          cellular                                                          cells          avascular                                                       extracellular matrix          apical and basal surfaces                                     fibers - collagenous, elastic, reticular          basement membrane                                           ground substance                                                                               vascular (exc. cartilage and blood)     nervous tissue:          excitability                                                 muscle:          cellular                                                            excitability and contractility              neurons                                                       cellular  (visceral)              neuroglia                                                      types: skeletal, cardiac, smooth          vascular (in C.T. wrappings)                             vascular (in C.T. wrappings)    Connective Tissue   Connective tissue (C.T.) is responsible for bodily integrity, support, transport, storage, and defense.  It basically holds the body together.  It produces the cells and antibodies of the immune system and serves as the first "battleground" of defense against invading pathogens.  It stores extracellular fluids, salts, and nutrients.  It transports salts, gases, nutrients, wastes, and metabolic control substances for the maintenance of the other tissues.   There are four principal types of connective tissue:   1)   C.T. Proper 2)   Cartilage 3)   Bone 4)   Blood   Connective tissue is found all over the body, and has the following structural characteristics:   1)   It is composed of cells, an extracellular ground substance, and extracellular fibers  (except for blood)   2)   It is predominantly extracellular, that is, most of the volume is extracellular (except for adipose tissue) and most of its functional properties derive from the extracellular material (except for blood and adipose tissue).   3)  It is vascular (except for cartilage and blood).   We will study C.T. proper this week; cartilage, bone, and blood in later weeks.   Connective Tissue Proper  {FAP 5.2, FAP Figs 5.5 - 5.6 - pp. 111-113}   Look for the following types of C.T. proper in the demonstration slides.  Pay attention to where each is found:   1)   Loose Irregular (Areolar) Connective Tissue                              -   What are the types of resident cells in areolar C.T.?  What are the fiber types?   -    In what body structures do you find areolar C.T.?   2)   Dense Irregular Connective Tissue                                           -   What are the tensile properties of dense irregular connective tissue, i.e. in what directions can it stretch and in what directions does it resist tearing?   -    In what body structures do you find dense irregular collagenous C.T.?   3)   Dense Regular Collagenous Connective Tissue                         -   What are the properties of collagen fibers? What cells produce and maintain these fibers?   -    What are the tensile properties of dense regular collagenous connective tissue, i.e in what directions can it stretch, in what directions does it resist stretching, and in what directions does it resist tearing?   -    In what body structures do you find dense regular collagenous C.T.?     4)  Dense Regular Elastic Connective Tissue                      -    What are the properties of elastic fibers? What cells produce and maintain these fibers?  How can you distinguish elastic from collagen fibers?   -    What are the tensile properties of dense regular connective tissue, i.e. in what directions can it stretch, in what directions does it resist stretching,  and in what directions does it resist tearing?   -    In what body structures do you find dense regular elastic C.T.?      5)  Reticular Connective Tissue                                                      -   What is the function of a reticular C.T.  meshwork?   -    In what organs do you find dense regular elastic C.T.?      6)  Adipose Tissue                                                                             -    What is the general function of adipose tissue?  What is the difference between brown and yellow fat?  Notice how the nuclei are flattened against the cell wall to maximize available intracellular storage space.   -         Why do you suppose that fat cells don't stain very well with standard water-soluble histological stains?   -    Where in the body can you find adipose tissue?   back to top=   Guide to Physiology   Diffusion   Follow APL Exercise 4.2 to perform simple tests of diffusion through an open medium.   Exercise 4.2.1 - Temperature dependence of diffusion through water.   1) Obtain two 100 ml beakers.  Fill one with hot tap water and one with cold tap water.   2)  Carefully add two (2) drops of food coloring to the center of the surface of each beaker.  Try not to disturb the surface of the water as you add the food color.   3)  Measure from the side with a ruler once per minute for five minutes to determine how far the coloring has spread in each beaker.  Record your results   In which beaker did the food coloring diffuse faster?   Exercise 4.2.2 - MW and concentration dependence of diffusion through agar.   1) Obtain 4 agar-filled petri dishes.  Note the small well in the center of each. Use a Sharpie pen to number your four dishes 1-4 on the transparent cover.   2)  Carefully fill the central well of each dish with the following dye solutions:       # 1 - 0.1M potassium permanganate  (MW =158g/mole)       # 2 - 1.0M potassium permanganate  (MW =158g/mole)       # 2 - 0.1M Methylene Orange   (MW = 327g/mole)       # 2 - 0.1M Congo Red   (MW = 697g/mole)         NOTE:  HANDLE THESE DYES WITH EXTREME CARE: THEY WILL STAIN AND MAY IRRITATE YOUR SKIN!   3)  Measure from the top with a ruler once every 10 minutes for fifty minutes to determine how far each dye has spread.  Record your results.   Did the smaller or larger dye molecules diffuse faster (compare dishes #1, #3, and #4)?   Did concentration have any effect on diffusion rate (compare dishes #1 and #2)?   Osmosis   Follow APL Exercise 4.3 to test osmosis in mammalian red blood cells.  We will use 100mM, 300mM, and 1200mM sucrose as our test solutions.   Exercise 4.3 - Osmosis in Red Blood Cells   BE SURE TO WEAR GLOVES AND WORK OVER AN ABSORPTIVE SURFACE WHEN HANDLING ANY MAMMALIAN BLOOD.  DISPOSE OF GLASS SLIDES AND COVERSLIPS INTO THE BLEACH-FILLED BEAKER.  DISPOSE OF OTHER CONTAMINATED MATERIALS INTO THE ORANGE AUTOCLAVE BAG.   1)  Obtain and number four clean microscope slides #1-4 .  Number each near one end, using a Sharpie pen..   2)  Carefully place one drop of mammalian blood in the center of slide#1.   3)  Carefully place a coverslip on the slide.  Try to avoid trapping bubbles.   4)  Starting at low power (40x) and proceeding up to high power (400x), observe the blood cells.  Note the characteristic round, "biconcave" shape of the predominant red blood cells (RBCs).   5)  Now, carefully place one drop of blood in the center of each of the remaining three slides        (#2-4).  To each slide add one additional drop of a sucrose solution:         #2 - 100mM sucrose       #3 - 300mM sucrose       #4 - 1200mM sucrose   6)  Carefully place a coverslip on each slide.  Try to avoid trapping bubbles.   7)  Set the slides on flat on the absorptive surface and wait five minutes.   8)  Carefully examine each slide and record the shape and appearance of the red blood cells.  You will have to go to high power (400x - 3rd objective) on the microscope to do this .   For which solution did the RBCs swell and burst (hypotonic)?   For which solution did the RBCs remain biconcave (isotonic)?   For which solution did the RBCs shrink and crenelate (hypertonic)?   Assuming that sucrose is impermeant to RBC membranes, what is the approximate osmolarity of the inside of the RBC (and physiological blood plasma)?   back to top=
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