BIOLOGY 113 LABORATORY Microscopes, Cells And Tissues
BIOLOGY 113 LABORATORYMicroscopes, Cells and TissuesObjectives To learn the proper use and care of compound microscopes To learn staining techniques used in light microscopy To determine the magnification of the microscope To be able to identify the four major types of vertebrate tissues (epithelial,connective, nervous and muscle). To understand how each type of tissue is organized and the distinguishing featuresof each type of tissue. To associate tissue structure with its function for each tissue type.IntroductionThe ability to magnify specimens has been around since 1000 B.C. The first simplecompound microscope that utilized two lenses was not invented until the late 16thCentury. It was the invention and modification of this microscope that changed the wayscientists studied living organisms. It allowed scientists to study the structure of a livingorganism and to discover numerous species that were not visible to the unaided eye.Today there are numerous types of microscopes available to scientists that providegreater magnification and superior detail (resolution). Besides magnifying andresolving an object, the microscope also provides the contrast that is needed todistinguish detail between adjacent objects. Microscopes used in most biologylaboratories magnify up to 1000X with a resolving power of 0.2 μM. The microscopes inthis laboratory are compound, light microscopes. The light is transmitted through thespecimen on the stage and through two lenses before it reaches the user.These are expensive pieces of equipment. Please handle them carefully.A. USING THE MICROSCOPEThere are some basic rules that you need to adhere to when using microscopes. Theseare:1. Always use two hands when moving your microscope. Use one hand to holdthe arm and the other hand should support the base. NOTE: The scopes areheavy!2. Use only LENS PAPER to clean the lenses. Do not use tissues, paper towels,Kimwipes, your shirt, etc. to clean the scope. Even though these items mayfeel soft, they can scratch the lenses.3. The microscope must be on the lowest power objective lens:a. when starting to use the microscope.b. when you finish using the microscope. Before you return the microscopeto its numbered slot: 1) make sure the objective lens is on the lowestpower, 2) the power is off, 3) there is no slide on the stage and 4) the dustcover is in place.Bio 113 Lab. Scopes, Cells and TissuesPage 1 of 20
4. NEVER use the course focus knob on high power; use ONLY the fine focusknob. These microscopes are parfocal. This means that when the image is infocus on one objective, the image will be in focus with the other objectives. Youmay need to fine focus the image for sharpness.Functional Parts of the Microscope:Materials:Microscope, lens paper, letter “e” slideProcedure:1. Remove the microscope from the scopes cabinet and return to your work area.2. Make sure that you use both hands to support the microscope (arm and base).3. Place the base securely on the lab bench with the arm towards you.4. Identify the following parts of the microscope:a. The ocular lens or eyepiece is a 10X lens which is at the upper end of thetube. The scope that you are using is binocular; it has two eyepieces.b. Revolving nosepiece: the objective lenses are attached below thenosepiece. It allows the user to change the magnification.c. Objective lenses: our scopes will either have 3 or 4 objective lensesattached to a revolving nosepiece. The magnification is inscribed on eachlens. The powers that you will use are: scanning (4X), low (10X) and highdry (40X). Most of our scopes also have an oil immersion objective lens(100X). You will not use this lens in this lab.d. Stage and stage clamp: the slide will rest on the stage and will be held inplace with the stage clamp. The moveable portion of the stage clampshould only be touching one corner of the slide.e. Iris diaphragm lever: on the front edge beneath the stage is a small leverthat is used to adjust the contrast by regulating the amount of light.f. Condenser and adjustment knob: the condenser condenses the light raysinto a stronger beam. Use the adjustment knob located below and to theside of the stage to increase or decrease the light intensity.g. Coarse Adjustment Knob: On each side of the scope is a large knob useto move the stage up and down to focus the image. This knob is to beonly used with the scanning and low power objective lenses.h. Fine Adjustment Knob: Located by the coarse adjustment knob, this knoballows for very small changes to the height of the stage. This knob is usedto increase the sharp focus of an image and is the only knob to be usedwith high power.i. Slide Movement Knobs: To one side of the stage, there are two black orsilver knobs that you will use to move the slide. One knob will move theslide to the left and right. The other knob will move slide towards andaway from you. The scopes are parcentral. This means that when youhave the object centered in the field of view on a lower power and thenchange to a higher power, the image will remain in the center of the fieldof view.Bio 113 Lab. Scopes, Cells and TissuesPage 2 of 20
Introduction to the Human TissuesTissues are formed when cells with similar structure and embryonic origin areaggregated together, performing a particular function. In this laboratory you willexamine the four major groups of tissues based upon their structure and function:epithelial, connective, muscle and nervous tissues. The study of tissues, especiallythe structure and arrangement, is called histology.Today, we will examine humans from the tissue level of organization up. As you recall,tissues are grouped to form organs which work together as systems.Atomic Molecular Cellular Tissue Organs Organ systems OrganismA. EPITHELIAL TISSUEEpithelial tissue form sheet like layer of cells with very close cell to cell contact.They function in protection, absorption and excretion of materials for an organism.Epithelial tissue is classified based upon 1) the number of layers and 2) the shape of thecells on the free surface:Simple epithelia are surface linings consisting of a single layer of cells. These areusually found at places where selective diffusion, absorption, or secretion occurs.Simple epithelia can range from squamous (flattened) to cubiodal to columnar inBio 113 Lab. Scopes, Cells and TissuesPage 3 of 20
shape depending on their function. All epithelial cells secrete a non-living matrix calledthe basement membrane. This is essentially a dense layer of extracellular materialthat acts as a “glue” to hold cells together.Simple squamous epithelium: a single layer of thin flattened cells, usually containinga flattened nucleus. They line the lumens of the entire blood vascular system(specifically called endothelium here), the renal corpuscles, and the lumenal surfacesof the pleural and peritoneal membranes. In these areas, they function in diffusion ofmaterials. They also line the thoracic, abdominal and cardiac cavity (mesothelium). Observe dorsal view of the frog skin (may look hexagonal) Observe the cross section of a blood vessel and find the endothelium that linesthe lumen of the blood vessel.Bio 113 Lab. Scopes, Cells and TissuesPage 4 of 20
Simple cubiodal epithelium: a single layer of cube-shaped cells with a centrallylocated nucleus. This epithelial tissue can be found in exocrine glands (salivary andmucus), lining small ducts and tubules (kidney tubules). They function in secretion andsome diffusion. Other areas found: ovaries and pancreatic duct You may be looking at the kidney tubules; thus look for circular tubes composedof simple cuboidal cells.Bio 113 Lab. Scopes, Cells and TissuesPage 5 of 20
Simple columnar epithelium: the height of these cells are great than the width and thedepth. All the cells touch the basement membrane and the nuclei are usually aligned inthe center or towards the bottom of the cells. Some cells are ciliated. These cells arespecialized in secretion and some absorption. Goblet cells are often associated withcolumnar cells and secrete mucus. Are any of these cells ciliated?Locations: nonciliatedciliatedlines stomach & intestinesuterine tubessome salivary glandsfallopian tubesgall bladderupper respiratory tractBio 113 Lab. Scopes, Cells and TissuesPage 6 of 20
Psuedostratified columnar epithelium: all cells begin at a common basementmembrane but some cells do not reach the free surface. The nuclei in largestdimension of cytoplasm; therefore, appear in two rows, thus the appearance ofstratification. Some may be ciliated. Typical locations include: eustachian tubes, upperrespiratory tract, epididymis, vas deferens. They are typically found in areas of highabuse forming linings.Bio 113 Lab. Scopes, Cells and TissuesPage 7 of 20
Stratified squamous epithelium: composed of cells with many layers, cells flattened atfree surface but typically cuboidal or columnar at basement layer. They function inprotection and coverings, in areas with lots of abuse. Locations include: skin and liningwet surfaces: mouth, esophagus, and vagina.Bio 113 Lab. Scopes, Cells and TissuesPage 8 of 20
Transitional epithelium: Highly modified, stratified squamous epithelium that lines onlythe unrinary bladder, ureters and portions of the urethra. Cells of the basal layer appearcuboidal or columnar. When the tissue is streched the cells flatten and look squamous.Bio 113 Lab. Scopes, Cells and TissuesPage 9 of 20
B. CONNECTIVE TISSUEThere are two types of connective tissue: loose, the most wide spread connectivetissue, and dense connective tissue. Connective tissue is composed of cells andextracellular fibers imbedded in a ground substance (matrix). The ground substanceor matrix can be jelly-like, liquid or solid non-living cement of glue secreted by the cells.There are three types of fibers that are typically found in the various types of connectivetissue. Elastic fibers are composed of elastin (protein) with a stretchy and flexiblecharacteristic. These fibers form thin wavy lines that can be stained purple, red orbrown in color. Collagen fibers are composed of collagen protein and found only inanimals. These fibers are characteristically thick and resist stretching. When stained,they appear as thick wavy lines that are either pink or red. Reticular fibers areinelastic and branching forming a network. These fibers are difficult to see withoutspecialized staining.Cells that are found in connective tissues are named according to their function. Cellscalled “blasts” are responsible for production a particular substance, “clasts” areresponsible for reabsorbing substances, and “cytes” are resting or mature cells that arenot producing or reabsorbing substances. For example, fibroblasts produce fibers.Fibrocytes are mature fiber cells and fibroclasts are responsible for reabsorbing(breaking down) fibers.Loose Connective TissueAreolar connective tissue: this is the least specialized connective tissue in the adultorganism. This is essentially the “packing material” of the body. It is often foundanchoring blood vessels, nerves and body organs. Cells include fibroblasts,macrophages, mast cells, adipose cells, and plasma cells. Also present are elasticfibers and collagenous fibers. This tissue is found in the subcutaneous layer of skin; itsupports blood vessels, nerves and epithelia.Bio 113 Lab. Scopes, Cells and TissuesPage 10 of 20
Adipose tissue: the cells are the dominant feature with gigantic vacuoles for lipidstorage. Fibroblasts are present. Elastic & collagenous fibers are present but may notbe visible in sections. These fibers are laid down randomly in all directions. Adiposetissue can be found nearly everywhere but especially around the kidneys, heart, eyes,greater omentum, subcutaneous connective tissue.Bio 113 Lab. Scopes, Cells and TissuesPage 11 of 20
Dense Connective TissueWhite (dense) fibrous connective tissue: collagenous fibers are the dominant type offiber that’s arranged in wavy, parallel lines. Typical locations include tendons,aponeuroses, cornea, most ligaments and periosteum. The cell that you’ll see in thistissue is most-likely fibroblasts.Bio 113 Lab. Scopes, Cells and TissuesPage 12 of 20
Bone: bone is composed of collagen and mineralized calcium and phosphate salts.Compact bone is composed of numerous Haversian systems. Within each Haveriansystem there is a Haversian (osteon) canal that has an arteriole, venule, and nervesupply. Osteoblasts, the bone forming cells that wall themselves in within the lacunae.At that point they stop producing bone and are called osteocytes. The cells in lacunaeare interconnected by tiny branching channels called canaliculi. These channels allowfor the passage of nourishments to the cells from the blood supply. Nourishment canalso be passed from one osteon canal to another osteon canal via Volkmann’s canal.The osteoblasts/osteocytes are arranged in concentric layers called lamellae (this issimilar to the growth rings of a tree). The function of bone is for mechanical support,locomotion, protection and mineral salt reservoir.Bio 113 Lab. Scopes, Cells and TissuesPage 13 of 20
Hyaline cartilage: the most common type of cartilage (gristle). This cartilage containsboth elastic and collagenous fibers - neither is visible in light microscope prep. Withinthe lacunae are the chondroblasts which produce the ground substance, cartilage. Inthe outer portion of the cartilage are the chondrocytes. Locations include: articularsurface of bones, end of nose, fetal skeleton, trachea, costal cartilageBio 113 Lab. Scopes, Cells and TissuesPage 14 of 20
Elastic cartilage: within the matrix, there are numerous elastic fibers (resilience &flexibility). The lacunae are more densely clustered containing chondrocytes. Locationsinclude the external ear, auditory tube, and epiglottis.Vascular Tissue: Blood and lymph are derived from loose connective tissue withvarious cells called corpuscles (or formed elements) which are suspended in a fluidmatrix called plasma (ground substance).Vascular tissue transports nutritivesubstances, oxygen and hormones to tissues and carries away waste products.Erythrocytes, red corpuscles or red blood cells (RBCs): humans typically haveapproximately 4.5 - 5.0 x 106 RBCs/mm3. Mammalian RBCs are biconcave in shapebecause there is no nucleus present. Avian and amphibian RBCs are nucleated. Allcontain hemoglobin for oxygen and carbon dioxide transport.Leukocytes, white corpuscles or white blood cells (WBCs): WBCs areresponsible for the defense. Some release chemicals while others are phagocytic.Classification of WBCs are based on granules in the cytoplasm that stain.Agranulocytes: without granules in the cytoplasmo Lymphocytes: comprise 20-25% of the WBCs. They are small with alarge dark blue nucleus with thin crescent shaped rim of light bluecytoplasm. These are involved in the specific immune response (Tlymphocytes). B lymphocytes are responsible for making antibodiesagainst foreign antigens.Bio 113 Lab. Scopes, Cells and TissuesPage 15 of 20
o Monocytes: comprise 3-8% of the WBCs. They have a large, kidney orU-shaped nucleus. These are considerably larger than lymphocytes.They are phagocytic on foreign bodies in loose connective tissue. They’recalled macrophages when they are actively phagocytizing foreign bodies.Granulocytes: have granules that stain in the cytoplasmo Neutrophils: are the most numerous of the WBCs (65-75%). They havea nucleus with 3-5 interconnected lobes (typically 3 lobed). The granulesstain light pink-purple. They are phagocytic in connective tissue.o Eosinophils: comprises 2-5% of WBCs. They have bilobed nucleusthat’s often difficult to see. The granules stain red-orange or what evercolor the red blood cells are. The function of eosinophils is still relativelyunknown. However, there is an increase in their numbers with parasiticinfections and allergic reactions. Some may even secrete histamine.o Basophils: comprises less than 1% of WBCs. They have an S-shapednucleus that’s often obscured by the large, very dark purple granules. Nocytoplasm can be seen. If you do see blue cytoplasm, the cell is mostlikely a lymphocyte.Basophils are involved in the non-specificinflammatory response. They release histamine which causes rednessand swelling as a result of increased fluid movement into the area.Bio 113 Lab. Scopes, Cells and TissuesPage 16 of 20
MUSCLE TISSUESkeletal or striated muscle: You will observe two different sections of skeletal muscle,longitudinal and cross. In the longitudinal section, the fibers are large, long and straight.You should notice the long cells with striations and multiple peripheral nuclei. Theseare among the largest cells in vertebrate body (1 fiber 1 “cell”). Skeletal muscle cellsthat are thin in are capable of rapid activity (i.e. extrinsic eye muscles) whereas cellsthat are thicker, such as those found associated with the appendicular skeleton contractmore slowly but with greater force. These are also known as “voluntary” muscles of thebody because we have conscience control over them.In cross section, each “circle” represents one fiber and gives the massive end viewof myofibrils. Note peripheral nuclei that may be present.Bio 113 Lab. Scopes, Cells and TissuesPage 17 of 20
Smooth/nonstriated muscle: Smooth muscles have more of a spindle shaped cell withno striations. They are also mononucleated. These muscles are involuntary since wedo not have conscience control over these. They are found in organs of the body andvessels.Bio 113 Lab. Scopes, Cells and TissuesPage 18 of 20
Cardiac muscle: Cardiac muscle is also striated; however, the cells are branched andcontain a single central nucleus. Between the cells are the intercalated disks with gapjunctions. Found in the heart.Bio 113 Lab. Scopes, Cells and TissuesPage 19 of 20
NERVOUS TISSUENervous tissue is composed of neurons. The basic anatomy of neuron consists of acell body or soma that contains the nucleus. There may be numerous extensionscalled dendrites around the soma which function in receiving electrical impulses fromvarious stimuli and transmitting this information to the soma. The longer axon thencarries the impulses away from the soma to a particular organ to elicit an affect. Theaxon may or may not be myelinated. Myelinated axons are enclosed by concentricrings of lipid layer that insulates the axon. The myelin sheath is produced by Schwanncells. Between each myelin sheath are small gaps in which the axon is actuallyexposed portion called nodes of Ranvier. As the nerve impulse is forced to “jump”(salutatory conduction) from node to node down the axon, the rate of conduction isincreased. At the end of the axon, there are numerous axon termini which innervatevarious structures. At the end of each axon terminus is the foot or terminal bouton.The small gap between the terminal bouton and the innervated structure is called thesynapse. This is where the release of neurotransmitters takes place.Giant multipolar neuron: In a smear from spinal cord, you will observe numerousneurons that typically stain bluish-purple. You should be able to see the soma,nucleus, nucleolus and dendrites.Myelinated axon:Schwann cells create the myelin sheaths that are composed oflipids. Can you find the nodes of Ranvier?Bio 113 Lab. Scopes, Cells and TissuesPage 20 of 20
Bio 113 Lab. Scopes, Cells and Tissues Page 1 of 20 BIOLOGY 113 LABORATORY Microscopes, Cells and Tissues Objectives To learn the proper use and care of compound microscopes To learn staining techniques used in light microscopy To determine the magnification of the microscope .
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How We Classify Stereo Microscopes Stereo microscopes, also known as low magnification and dissecting microscopes share a number of common, fundamental components. . microscope head, this is the main way that different types of stereo microscopes are classified, and priced, examples of all these types are included in this product range datasheet.
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The microscopes of Antoni vun Leeuwenhoek 31 1 that van Leeuwenhoek made at least 566, or by another reckoning 543, microscopes or mounted lenses. In the total are included twenty-six silver microscopes bequeathed to the Royal Society. Of all these instruments, only very few have survived; the Royal Society's microscopes were lost in about 1850.
magnification and superior detail (resolution). Besides magnifying and resolving an object, the microscope also provides the contrast that is needed to distinguish detail between adjacent objects. Microscopes used in most biology laboratories magnify up to 1000X with a resolving power of 0.2 μM. The microscopes in
Lesson Overview Life Is Cellular Electron Microscopes Light microscopes can be used to see cells and cell structures as small as 1 millionth of a meter. To study something smaller than that, scientists need to use electron microscopes. Electron microscopes use beams of e
GX Microscopes models that have the suffix 'HBG' are always binocular, eg L3000 HBG L1500 HBG Trinocular A trinocular head is a binocular head with a prism which diverts some or all the light to . GX Microscopes supply a range of different stage types.
tank; 2. Oil composition and API gravity; 3. Tank operating characteristics (e.g., sales flow rates, size of tank); and 4. Ambient temperatures. There are two approaches to estimating the quantity of vapor emissions from crude oil tanks. Both use the gas-oil ratio (GOR) at a given pressure and temperature and are expressed in standard cubic feet per barrel of oil (scf per bbl). This process is .
