Histology Exam 1 and Practical 1 fully solved & updated

Resolution - ANSWER-Ability of a microscope to distinguish two objects as separate What do you call a measurement of 10^-6 m? - ANSWER-Micrometer, or micron Light Microscope - ANSWER-microscope that uses a beam of light passing through one or more lenses to magnify an object What resolving power does a light microscope have? - ANSWER-0.25 micrometers Types of Light microscopes (4) - ANSWER-- Simple (Dissecting) - Compound (What we use in lab to view slides regularly) - Dark Field (Cout out center of cone of light to highlight the edges of an object) - Phase Contrast Microscope Transmission Electron Microscope (TEM) (Resolving power) - ANSWER-A microscope that reads electrons passed through a sample to produce an image (2-3 A) Scanning Electron microscope (SEM) and (resolving power) - ANSWER-an electron microscope useful for studying the surface of cells, the resulting images have a 3D appearance (30-75A) How large is an Angstrom? - ANSWER-10^-10m Parts of optical train (LM) - ANSWER-3 lens systems: - condenser - objective - eyepiece Condenser - ANSWER-focuses light through the specimen; The NA of the condenser must match the NA of the objective lens Numerical Aperture - ANSWER-standard; a mathematical expression that describes how the condenser lens concentrates and focuses the light rays from the light source; higher NA = greater resolving power Objective - ANSWER-"a projection lens"; can switch them on the LM to get different magnifications Achromats - ANSWER-Simple; An objective lens that magnifies light without the light splitting into its colors (usually corrects red and blue) Apochromats - ANSWER-Simple; variety of glasses that correct for chromatic (spherical) abberations plan apochromat - ANSWER-flat field of view; corrects for curvation, best for photomicrography Eyepiece - ANSWER-magnifies image formed by objective within the body of the tube and presents the eye with a visual image in the plane of the objective being observed; usually at an optical distance of 250mm from the eye. Working distance - ANSWER-distance between objective lens and specimen (Inversely related to magnification) Depth of focus - ANSWER-ability to see objects in different planes. Higher magnification leads to lower depth of focus Dark ground/field illuminator - ANSWER-Used to illuminate the edges of the specimen Magnification - ANSWER-Makes things look larger Contrast - ANSWER-visual differentiability (Primarily add contrast with color) Types of illuminators - ANSWER-- Crtitical - light source is focused by the condenser in the same plane as the object - Kohler - Includes an adjustable collector lens in front of the lamp which focuses the source in the plane of the iris diaphragm of the condense; provides even and homogeneous illumination at the object plane. Lens aberrations - ANSWER-in reality, images are often blurred and exhibit departures from theoretical images called How to calculate Numerical Aperture - ANSWER-nxsinµ - where n is the refractive index of the medium between cover glass over the object and the front of the objective lens, and µ is the 1/2 visual angle (angle from bisector of total visual angle to the edge of the cone of light) Abbe Formula - ANSWER-R = 0.61λ / N.A. Where R is the resolutiom of the medium, lambda is the wavelength of light, and NA is the numerical Aperture. Refractive index - ANSWER-Relative speed of light in a medium compared to a vacuum. What does a high n do to the Numerical Aperature? To the resolution? - ANSWER-Since n is used to determine NA, a high n will result in a high NA, which gives strong resolving power. Since NA is used to calculate Refractive index, a high n means that the medium has a low refractive index. Fluorescence microscope - ANSWER-Type of microscope that uses UV light to produce a longer wavelength light to be reradiated by the specimen. Certain structures that are marked with a fluorescent material or that naturally fluoresce would be made visible. inverted real image - ANSWER-Image created from light that is actually coming directly from the object, and is upside down and backwards (Usual image in a LM) iris diaphragm - ANSWER-Part of the condenser that regulates how much light moves through the object Phase contrast microscope - ANSWER-emphasizes differences in specimen's capacity to bend light waves. more 3D image. It creates high contrast images. Polarizing Microscope - ANSWER-A microscope that uses different light transmission characteristics of materials, such as crystalline structures, to produce an image. It uses a beam of polarized light that experiences interference from the sample. Virtual image - ANSWER-an image that forms at a location from which light rays appear to come but do not actually come Rudolph Virchow (1855) - ANSWER-determined that cells come only from other cells; pathology arises from cells (sick from bacteria, etc.) In Vivo - ANSWER-In a living organism (vet can create a fistula, a permanent window into the stomach of a cow, from which they can take samples) In vitro - ANSWER-Outside of a living individual (ex. cell and tissue cultures) Intravital staining - ANSWER-Staining within a living individual; usually a vascular injection that gets circulated (ex. Trypan blue stainging where macrophages ingest blue pigment) Supravital Staining - ANSWER-Remove the living tissue and stain before death Histotechniques - ANSWER-How tissue is prepped to be examined for LM and TEM. They make 3 dimensional tissues into slides that allow for 2d images or micrographs. They add contrast to components of transparent tissues to allow for their visualization. The main goal is to preserve the real-life look. Routing to prepare a slide (Generally an H&E stained slide) - ANSWER-Fixation Washing and Dehydration Clearing Infiltration Embedding Sectioning Staining Fixative - ANSWER-A chemical or mixture that permanently preserves tissue structures, as close to real life as possible, for subsequent treatments to enhance contrast between components. A good fixative - ANSWER-- Penetrates rapidly, - Coagulates contents into soluble substances - Prevents Shrinkage and distortions - Saves wanted parts - Prepares tissues for staining - Enhances Dye attraction Fixation - ANSWER-Preserves tissue structures as close to real life as possible Washing and Dehydration - ANSWER-Removes the fixative and dries out the sample (dehydration makes it easier to slice the sample) Clearing - ANSWER-Clears out water to replace with something to make soluble in embedding medium; so-called because it removes pigmentation. Infiltrate - ANSWER-let embedding medium seep into the sample Embedding - ANSWER-embed in a medium to make slicing easier Common embedding media - ANSWER-Paraffin and plastic (non-water-soluble which is also why the sample must be dehydrated) Fixatives: Formalin - ANSWER-4% formaldehyde, proteins; is sold as 37% formaldehyde (gas dissolved in aqueous solution) and is buffered by Phosphate to around a 3.7% solution. Fixatives: Aldehydes in general - ANSWER-proteins; ; crosslinks proteins. glutaraldehyde, paraformaldehyde - choise of TEM in mixtures Karnovsky's fixitive - a combination of glutaraldehyde and paraformaldehyde in variable concentrations. Fixatives: Acetic acid - ANSWER-nucleoproteins Fixatives: EtOH - ANSWER-carbos, enzymes (and some other proteins) Fixatives: Chromic Acid (CrO3) - ANSWER-reduces shrinkage, nucleoproteins, carbos to aldehydes, oxidizes fats (insol.) Fixatives: Potassium dichromate - ANSWER-K2Cr2O7 oxidizing agent, dissolves nucleoproteins, good for carbos, lipids & mitochondria Fixative: Picric Acid - ANSWER-glycogen, carbos, increases hardness Fixative: OsO4 - ANSWER-nucleic acids, fats Fixatives: Acetone - ANSWER-enzymes Fixatives: Mercuric chloride - ANSWER-HgCl2 reduces shrinkage, nucleic acids, fats Fixative Mixtures: Bouin's Fixative (PAF) - ANSWER-Picric acid, Acetic Acid, Formalin Fixative MIxtures: Bouin-Duboscq (PAA) - ANSWER-Picric acid, Acetic Acid, Alcohol (EtOh-95%) Fiative Mixtures: AFA - ANSWER-Acetic Acid, Formalin, Alcohol (EtOH -95%) Fixative Mixtures: Helly's - ANSWER-potassium dichromate, mercuric chloride, formalin Fixative Mixture: Zenker's - ANSWER-potassium dichromate, mercuric chloride, acetic acid Why stain? - ANSWER-- Tissues do not absorb visible wavelengths to render contrast - Staining adds contrast - Correctly chosen stains aid in the identificatio of tissues and their elements -Diagnoses Nature of dyes - ANSWER-Chromophores or chromogen - part that absorbs light and imparts the color (In acidic dyes, it is the negative part, and v.v.) Auxochromes - dissociate from the dye to form a salt that attaches to the substrate (Ex. Cationic -NH2 - NH3+; Anionic SO3H - SO3-) Mechanism of Staining: Electrostatic - ANSWER-Proteins in solutions, takes advantage of the amphoteric properties of dye-protein interactions (Van Der Wall's, H-Bonds, acidophillic, basophillic) Mechanism of Staining: Metachromasia (metachromasy) - ANSWER-polymerization phenomena (when the dyes are in higher concentrations the pigments polymeraize and light absorption shifts, as in methylene and toluidine blues. In Toluidine blue, the shift makes the color a dark purple.) Mechanism of Staining: Histochemistry, cytochemistyr, immunohistochemistry - ANSWER-selective staining reactions, radioisotope uptake, selective metal distribution/uptake, e.g., alkaline phosphatase localization Mechanism of Staining: Fat soluble dyes and fat storage - ANSWER-Require special techniques, otherwise they appear as a negative image. Mechanism of Staining: Radioautography - ANSWER-H3, I125, and C14 use in the cells, then placing the sample for staining on x-ray paper to get an image. Hematoxylin dye - ANSWER-Basic dye (Stains acids, like RNA and DNA a bluish purple as well as the rER); It is usually counterstained with eosin. Eosin dye - ANSWER-Acidic dye (Stains basic structures; cytoplasm, elastic fibers, reticular fibers, and collagen fibers pink); it is generally used with Hematoxylin Hematoxylin and Eosin dye example - ANSWER- Acidic Dyes - ANSWER-Acid fuschin; Aniline Blue; Eosin; Orange G Basic Dyes - ANSWER-Methyl Green; Methylene blue; Pyronin G; Toluidine Blue Mallory's trichrome - ANSWER-Composed of aniline blue, acid fuschin, and orange G. Stains Nuclei red, cytoplasm pale red, red blood cells orange, collagen fibers deep blue, keratin orange, bone matrix deep blue, and muscle fibers red. (Usually used to stain connective tissue) Periodic Acid Schiff - ANSWER-Used to stain the basement membrane and localizing carbohydrates. Stains the nucleus blue, collagen fibers pink, and glycogen and other carbohydrates magenta. Silver stain - ANSWER-aka silver nitrate; stain that binds to certain glycoproteins; The golgi body and reticular fibers have specific glycoproteins that bind to the silver stain Secretion - ANSWER-process by which cells extrude physiological useful substances Excretion - ANSWER-Undigested and waste products eliminated Cell differentiation - ANSWER-Process of forming specialized cells from unspecialized cells: Fertilization Cleavage Gastrulation Germ layers - ANSWER-Ectoderm, mesoderm, endoderm Ectoderm - ANSWER-Becomes nervous system, skin, sense organs, hair, cornea, lens Mesoderm - ANSWER-Becomes connective tissue, muscle, blood Endoderm - ANSWER-Becomes epithelia of GI, UG, Resp., Sexual accessory glands, many endocrine glands Organogenesis - ANSWER-Once primary tissues in place by gastrulation, morphogenesis and differentiation of functional organs begins. Cartwheel state of the nucleus - ANSWER-Point when the Heterochromatin (electron dense) around the nucleus and the euchromatin (electron lucent) around the nucleolus looks like the wheel of a cart. Nucleolus - ANSWER-Responsible for synthesizing ribosomes. Euchromatin - ANSWER-The less condensed form of eukaryotic chromatin that is available for transcription. Heterochromatin - ANSWER-Eukaryotic chromatin that remains highly compacted during interphase and is generally not transcribed. How many layers does the nuclear envelope have? - ANSWER-Two, the outside one has pores. Nuclear pore - ANSWER-Where 2 layers are joined together, contain special proteins that act as gates to let some things in and keep others out; let in histone proteins and nucleic acids; let out types of RNA; tend to be evenly spaced out and differ in number in different cells. Mitochondria - ANSWER-Outer and inner mitochondria membranes; inner can form sacs or tubules; they are the only self-replicating organelles; contain enzymes for the TCA (CAC, Krebs, etc.) cycle; the inner matrix is like a "soup"; the cristae are the location of oxidative phosphorylation; Have their own DNA that may be visible. (The dark spots may be DNA); they are very basic components of cells (they will attract acidic dyes, like eosin) made of basic proteins. RER - ANSWER-AKA Ergastoplasm; Involved in protein production that will be put into vesicles (Sent to golgi to other cells or used in lysosomes); Protein processing from the RER occurs when a blebbing event from the cistern of the RER creates a vesicle and motor proteins carry the vesicle to the golgi (if the product is an enzyme, the enzyme will not be produced until it is activated at the location it is needed. Where do the ribosomes on the RER come from? - ANSWER-They all start out as free ribosomes that attached to the RER when a specific signal sequence on mRNA is read. Where does lipid synthesis occur? - ANSWER-In the cytoplasm What is the granular endoplasmic reticulum? - ANSWER-RER What is the agranular endoplasmic reticulum? - ANSWER-SER Smooth Endoplasmic Reticulum - ANSWER-Labyrinth-like; highly variable, inconsistent, ill-defined shape, involved in lipid MODIFICATION (not synthesis) Relationship between nucleus and RER - ANSWER-The RER is a derivative of the nuclear envelope. It may be connected to the nuclear envelope through a pore that opens into an ER cistern. Golgi - ANSWER-Look like crescent moons; responsible for seminal production; series of interconnected, flattened saccules; packaging, modifying, and sending proteins. They have no ribosomes and produce vesicles (Which may have lysosomes or granules); my be distended if ER or Golgi are backed up. Primary lysosome - ANSWER-formed by golgi apparatus and contains inactive enzymes Secondary lysosome - ANSWER-Membrane-enclosed organelle formed by the fusion of a primary lysosome with a phagosome, in which macromolecules taken up by phagocytosis are hydrolyzed into their monomers. This may activate the enzyme in the lysosome Tertiary Lysosome - ANSWER-(aka residual body) contains undigested debris that may also contain lipofuschin (aging pigment) and so appear dark Canaliculus - ANSWER-Very small tube or channel,(Which are especially found between lacunae of bone) that may Types of filaments - ANSWER-microfilaments (like actin), intermediate filaments (Like myosin), microtubules Centrioles - ANSWER-Present in every cell; are the microtubule organization center; serve also as anchor points for cilia (They are then called basal bodies) Basal bodies - ANSWER-centrioles forming the bases of cilia and flagella Spindle fibers - ANSWER-Filaments anchored to centrioles that are used in mitosis and meiosis to pull apart chromosomes and chromatids. Basal bars - ANSWER-3 cell-to-cell junctions that form a junctional complex between cells. Zona occludens, zona adherens, and macula adherens Zona occludens - ANSWER-Forms a ring around the cells (most apical of the 3 in the junction complex). Fuses all cells together and prevents the unwanted movement of fluid. The zona occludens is also known as the tight junction. Zona adherens - ANSWER-Girdle of glycoproteins that surrounds the cells and binds cells together; also acts as an anchor point for cytoskeletal elements Macula adherens - ANSWER-AKA desmosomes. "Spot welds" in the lateral domain between cells that do not surround the whole cells. What do you look for in order to tell if there are microvillli? - ANSWER-In addition to the brush border, you can look for a terminal web Phagosome Formation - ANSWER-A little outfolding of the plasma membrane pokes out and surrounds a piece of debris (usually food) and creates what is called a marginal fold. When the end of the marginal fold creates a little bubble and joins with the plasma membrane, the bubble formed is a phagosome that may combine with a lysosome to form a hetero lysosome that will digest the particle. Pinocytosis - ANSWER-Lesser used word for cell drinking (now we just use endocytosis more often); it is an infolding of the cell membrane. Transcytosis - ANSWER-transport into, across, and then out of cell Basolateral infoldings - ANSWER-Infoldings that increase the surface area of the cell at the basement membrane. The increase the capacity for active transport and are often filled with mitochondria so that the active transport can have energy. (When mitochondria populate the infoldings, they look striped or striated) Ribosomes - ANSWER-Multipart proteins (with rRNA) That act as protein factories. They may move to the endoplasmic reticulum if the protein produced has a signal sequence. Lipofuscin - ANSWER-the granular wear-and-tear pigment associated with aging Melanin - ANSWER-Pigment that gives skin its color, and is also found in the eyes (less for people with blue eyes) Secretory granules - ANSWER-Large, densely packed, membrane-bound structure containing highly concentrated secretory materials that are discharged into the extracellular space (secreted) following a stimulatory signal. They may contain zymogens that will be secreted for digestion. Feulgen reaction - ANSWER-stains DNA Autophagy - ANSWER-self eating Heterophagy - ANSWER-ingestion of outside material for intracellular destruction M Stage: Mitosis - ANSWER-•Mitosis (2 identical cells created from a single cell) + cytokinesis (splitting of cytoplasm and organelles into 2 daughter cells) •Occurs in somatic cells (cells not involved in sexual reproduction) •Mitosis consists of 4 phases G1 phase - ANSWER-The first gap, or growth phase, of the cell cycle, consisting of the portion of interphase before DNA synthesis begins. S phase - ANSWER-The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated. G2 phase - ANSWER-The second growth phase of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs. Coated vesicles - ANSWER-They form when the surface of a cell has protein receptors. The receptors bind to a certain molecule (the end of an antibody for example) and the cells then endocytose the substance. (Opsonization occurs when macrophages recognize antibodies on a bacterium with their receptors. The Macrophage then engulfs the bacterium in the coated vesicle) Cristae - ANSWER-Infoldings of the inner membrane of a mitochondrion that houses the electon transport chain and the enzyme catalyzing the synthesis of ATP. They may be lamellar (sacular) or tubular. Transitional vesicles - ANSWER-vesicles that come to the golgi from the RER. Tubulin - ANSWER-protein that makes up microtubules argyrophilic - ANSWER-stains black with silver stain Artifacts - ANSWER-Part of a slide created by human error/preparation (cells shrink and so some layer pull away from others) cryostat - ANSWER-a freezing chamber for tissue samples Microtome - ANSWER-an instrument that produces very thin slices of body tissues radioautography - ANSWER-Using radioactive isotopes to label compounds in a cell, then exposing a film with the radiating specimen, Cillia - ANSWER-*Tiny hairlike extensions* that move together in a sweeping motion. The center of the cillia contains a circle of 9 tubule doublets and 2 single microtubules. (Present in respiratory epithelium, oviducts, and epididymus) Centrioles (with picture) - ANSWER-9 triplets of microtubules in a ring. They anchor things with microtubules. Alveolus of lung - ANSWER-Has a very thin layer dividing it from the capillary. The capillary shares a basement membrane with the alveolus in order to shorten diffusion distance. Basement membrane - ANSWER-Produced by epitheliul cells at the basal surface; functions as a molecular sieve and resting place for epithelial cells. The terminal web of a brush border is acidophillic or basophillic? - ANSWER-Basophillic Thyroid - ANSWER-Produces thyroid hormone that binds to globulin. The spaces of the thyroid (follicles) fill with colloid, which is taken up by the epithelial cells and released into the capillaries to regulate the metabolism. The thyroid is also a calcium-sensing organ, which detects calcium levels in the blood with calcium-sensing C-cells (clear cells). The C-cells secrete calcitonin, which lower blood calcium levels. What are a group of c-cells called? - ANSWER-A nest If the follicle of the thyroid is empty? - ANSWER-Then the thyroid is hyperactive (The epithelial cells will appear squamous or cuboidal) What kind of epithelium lines the trachea? - ANSWER-pseudostratified ciliated columnar with goblet cells Goblet cells - ANSWER-a column-shaped cell found in the respiratory and intestinal tracts, which secretes the main component of mucus. What type of epithelium is cutaneous? - ANSWER-Keratinized stratified squamous What is the purpose of parietal cells? - ANSWER-In the stomach, they secrete HCl; intracellular canaliculi form haloes to make proton pumps; they are also basophillic; Look for the haloed nuclei! Where will you find simple squamous epithelial tissue? - ANSWER-lungs, blood vessel lining Where will you find simple cuboidal epithelial tissue? - ANSWER-kidneys Where will you find columnar epithelial tissue) - ANSWER-small intestine Where will you find pseudostratified (ciliated) columnar epithelial tissue? - ANSWER-respiratory tract, ductuli efferentes, epididymis, vas deferens) Where will you find stratified squamous epithelial tissue (keratinized and mucous type)? - ANSWER-Keratinized - epidermis Mucous types - oral cavity Where will you find stratified cuboidal epithelial tissue? - ANSWER-salivary and sweat gland ducts, mammary gland ducts, circumanal glands (large terminal ducts) Where will you find stratified columnar epithelial tissue? - ANSWER-Large ducts, conjunctiva, male urethra and vas deferens, uterus, pharynx, and anus (relatively rare) Where will you find transitional epithelial tissue? - ANSWER-Distended in a full bladder, and contracted in an empty bladder; also renal pelvis, ureter, bladder, urethra, cribiform plate. Types of epithelial transport (of substances) - ANSWER-Absorption, reabsorption, secretion, osmoregulation Morphology reflects ____________ - ANSWER-function (mode) Thin epithelial are likely used for - ANSWER-diffusion Membrane redundancy reflects transport via - ANSWER-active transport, facilitated diffusion, or co-transport Membrane asymmetries reflect - ANSWER-directionality (Microvilli indicate flow in, and basal infoldings reflect flow out) Standing gradient hypothesis - ANSWER-In short, active transport at the basal surface of a solute (Na+ for example) creates a gradient that causes solutes to move down (into the cell) from the apical end. Transport mechanisms of epithelial cells - ANSWER-1. Vesiculation and bulk transport 2. Membrane redundancy and active transport 3. Standing Gradient Hypothesis What types of membranes are formed by epithelia? - ANSWER-Mucous (mucosa) Serous (serosa) Cutaneous (skin) Synovial Mucous (mucosa) - ANSWER-Epithelial membrane that lines tubes; moistens and protects from enzymes, debris, etc.; is found in the GI tract, trachea and bronchii, and reproductive system Serous (serosa) - ANSWER-Epithelial membrane of the peritoneum, visceral and parietal; lubricates (all thhoracic, abdominal, and pelvic organs) Cutaneous - ANSWER-Skin; an epithelial membrane; on the body surface; protecion Synovial epithelial membrane - ANSWER-synovial joints (covers in fluid); lines and protects synovial cavities (elbow, knee, hip, etc.) Gland - ANSWER-One of more cells that make and secrete a product Secretion (n.) - ANSWER-Prooduct in aqueous solution: hormones, acids, oilds Difference between endocrine and exocrine glands - ANSWER-Endocrine - release secretion into blood vessels; often release hormones; ex. thyroid, adrenal, and pituitary glands Exocrine - contain ducts, empty onto the epithelial surface; usuall sqeat, oil glands, salivary glands, and mammary glands. Ducts: simple v. Compound - ANSWER-Simple is unbranched, and compound is branched Gland endpiece shapes and definitions - ANSWER-Tubular - shaped like a tube (test-tube like) Alveolar - shaped like a flask or sac Acinar - cluster of cells Tubuloalveolar - has both tubes and sacs Three modes of secretion - ANSWER-merocrine, apocrine, holocrine Merocrine - ANSWER-A strategy of secreting hormones via exocytosis (Sweat glands, and salivary glands); it is also called eccrine Apocrine - ANSWER-A strategy of secreting hormones in which the apical (top) portion of the cell is destroyed to release the hormones (blebbing or decapitation of the cells); ex. mammary glands Holocrine - ANSWER-A strategy of secreting hormones in which the entire cell is destroyed to release the product; ex. sebaceous gland, sebum, oil glands on the face. Serous gland - ANSWER-Secretion is typically watery with many enzymes (proteonaceous); provides lubrication; cells have basophillic cytoplasm, and nuclei above the basal cytoplasm Mucous gland - ANSWER-Secretion is mucous, containing water and many glycosaminoglycans (GAGs); the cytoplasm is flocculent, with flattened basal nuclei, and they are heterochromatic; they are found in the digestive and respiratory systems; mucous can also be bicarbonate rich (to neutralize acid) Simple squamous example - ANSWER- simple cuboidal epithelium example - ANSWER- simple columnar with a brush border and goblet cells example - ANSWER- cilliated pseudostratified columnar with goblet cells - ANSWER- Keratinized stratified quamous - ANSWER- Stratified cuboidal - ANSWER-Note: Two layers is still considered stratified. transitional epithelium - ANSWER-This is contracted; also, look for binucleate cells when observing transitional epithelium Sensory epithelia, examples - ANSWER-Organ of Corti (structure of the inner ear which produces nerve impulses in response to sound vibrations); taste bud; retina; Meissner's corpuscle; Pacinian corpuscle; olfactory mucosa Seminiferous epithelium - ANSWER-Epithelium of the seminiferous tubules of the testis. Sertoli cells are a simple epithelium with extensive apical and lateral processes that surround spermatogenic cells. Canno be seen distinctly in routine H&E preps (look for tubes and sperm) Ovarian epithelium - ANSWER-germinal epithelium is a misnomer, it is actually a serosa continuous with the mesothelium. Follicular cells (granulosa) surround developing oocytes. epithelial tissue and functions - ANSWER-Surface tissues (not necessarily on every body surface, but most are) They may protect, secrete, absorb, transport, sense, or form gametes. General features of Epithelial tissues - ANSWER-1) Maximize cells and minimize extracellular material 2.) Avascular (little to no blood vessels) 3.) High regenerative capacity (AKA restitutive growth) 4.) Plasticity - functional and mechanical 5.)special responses (hormonal, nervous, gametogenic, and sensory) 6.) Polarized Normal v. Abnormal epithelial growth - ANSWER-Normal: a.) Continuous - usually follow circadian rhythms (ex b.) Sporadic - e.g., molting, shedding (ex. uterus) c.) Regenerative - restorative Abnormal: a.) benign - nonlethal, e.g., warts (verrucae) b.) Malignant = carcinomas Plasticity of epithelial tissues - ANSWER-Passive deformation - (mechanical) Functional considerations - hypoplasia, hyperplasia, metaplasia, hypertrophy, and dysplasia. hypoplasia - ANSWER-atrophy; underdeveloped hyperplasia - ANSWER-increase in cell number metaplasia - ANSWER-transformative (mucous type in oral cavity to keratinized with irritation) Hypertrophy - ANSWER-increase in cell content and function Dysplasia - ANSWER-changes associated with increased probability of disease development Types of special responses in epithelia - ANSWER-1.) Hormonal - thyroid, seminal vesicles, vagina, etc. 2.) Nervous - salivary glands, stomach, sweat glands, etc. 3.) gametogenic - testis and ovary 4.) sensory - act as receptors/sustentacular (Secondary receptors that aren't neural) sustentacular - ANSWER-support cells Structure of an epithelial cell - ANSWER-Epithelia are juxtaposed (attached) to a basement membrane; the upper surface is the apical surface which is the exposed surface; the basal surface is physically attached o the basement membrane; and the lateral surface is between adjacent epithelial cells. What part of a stratified epithelium categorizes the epithelium? - ANSWER-The most apical part (the oldest layer, not the basal layer) Intercellular spaces/cell surfaces in polarized cells: - ANSWER-basal, apical, lateral, basolateral (the basolateral domain is between the basal lamina and the junctional conplex) Cell adhesions and permeability barriers - ANSWER-1.) Junctional complexes a.) Occludens types : zonula occludens, and fascia occludens (membranes physically fused between cells) b.) Adherent types: Zonula adherens (like a belt), and macula adherens (desmosomes) c.) Electronic type: nexus or gap junctions (low resistance passages that are channels between cells) 2.) Membrane interdigitations Types of modifications for epithelial absorptions - ANSWER-1.) Microvilli and membrane infoldings 2.) Glyocalyx coat (cell coat) 3.) Canaliculi and caveolae Types of modifciations for diffusion - ANSWER-1.) Cell thinness 2.) Loose junctions 3.) Fenestrae 4.) Basal lamina permeability Caveolae - ANSWER-indentations in the plasma membrane that may function for endocytosis Types of modifications for electrolyte and water transport - ANSWER-1.) Exocytosis, transcytosis, and vesiccular trafficking 2.) Hepatic canaliculi, and intracellular canaliculi Modifications for electrolyte and water transport - ANSWER-1. Lateral and basal membrane infoldings 2. Abundant mitochondria (fuel for active transport) 3. Intercellular spaces (water is pushed out below the zonula occludens into the space between cells and then can diffuse or be transported through the basal membrane) 4. Microvilli Microvilli structure - ANSWER-Non-motile; actin is anchored to villin at tip of microvillus; actin interacts with the terminal web (horizontal actin) Cilia - ANSWER-motile processes (extensions); found in the respiratory system, oviducts, brain ependyma, olfactory epithelium; cilia are 9x2+2 with basal bodies (9x3, centrosomes); cilia extend from the basal body (centriole) and microtubule organizing center (MTOC) or centrosome Stereocilia - ANSWER-Non-motile and resemble microvilli (actin and fimbrin core); found in epidydimis, ductus deferens, sensory cells of inner ear (organ of Corti, utricles, cristae ampullaris of semicircular canals); They come in pairs with one large and one small. Chromatophores - ANSWER-pigment cells that change the color of an organism, allowing it to camouflage (dermis only) Phore - ANSWER-agent that bears something (A chromatophore is something that bears color) Stellate - ANSWER-star-shaped, radiating from the center in 3D space Types of chromatophores - ANSWER-iridophores - guanine, adenine, or hypoxanthine (purines) xanthophores (yellow) - pteridines and carotenoids erythrophores (red) - pteridines and carotenoids melanophores - melanin (TYR - DOPA - Melanin) via monophenol mono-oxygenase (tyrosinase) Melanocytes - ANSWER-Dendritic cells in the stratum basale (Dermis) of the skin Melanosomes - ANSWER-Pigment carrying granules that produce melanin and transfer it to the ECF or by "pigment donation" to keratinocytes (skin color is due to rate of melanin production, not # of melanocytes) In non-mammals, what is used instead of melanocytes? - ANSWER-Melanophores Vitamin A and D deficiency leads to - ANSWER-irreversible infertility, What are characteristics of the inner mitochondrial membrane? - ANSWER-Cytochromes, dehydrogenases, flavoproteins, and enzymes for oxidative phosphorylation Glycocalyx - ANSWER-The external surface of a plasma membrane that is important for cell-to-cell communication (Can exist outside of microvilli); it also traps mucous (neutralizes acids); houses enzymes for terminal digestion; Lipid droplet example - ANSWER-This is a unilocular adipocyte What are the three main layers of the skin and what are they made of? - ANSWER-Epidermis - keratinized stratified squamous epithelia (In the image, the top layer is the stratum corneum, and the second layer is the epidermis) Dermis - Dense Irregular Collagenous Connective Tissue Hypodermis - subcutaneous fat Two layers of the dermis? - ANSWER-Papillary Dermis - folds outwards into the epidermis to form papillae (may not be present in every type of skin, but are a key component of fingerprints); Reticular dermis What are the epidermal counterparts to the dermal papillae called? - ANSWER-The epidermal downgrowths are called pegs Stratum corneum - ANSWER-The red question mark is pointing to it; it containts dead, corneated cells Stratum germinativum - ANSWER-deepest layer of epidermis; cells that are undergoing mitosis; In the image, it is the dark line of cells. Stratum disjunctum - ANSWER-The outermost layer of the stratum corneum that is sloughing off. stratum granulosum - ANSWER-Outer layer of the nucleated cells in the epidermis. They are usually darkened because of the accumulation of keratohyaline (Layer B in the image) keratohyaline - ANSWER-The protein precursor to keratin which is the predominant form of the protein observed in keratinocytes in the stratum granulosum of the epidermis of the skin. What is the papillary layer of the dermis made of? - ANSWER-areolar connective tissue (loose connective tissue); it may contain nerves and capillaries. Stratum malpighii - ANSWER-refers to the stratum basale (germanitivum) and the stratum spinosum grouped together. (SS and SB) stratum spinosum - ANSWER-The spiny layer just above the stratum germinativum layer. It appears spiny under the microscope becase the preparation of slides may cause cells to shrink. The desmosomes connecting cells pulls on the cell and causes spines to appear, but they are not present in living tissue. mucin - ANSWER-a complex glycoprotein that dissolves in water when secreted; is the main protein element of mucous myoepithelial cells - ANSWER-Squeeze apocrine gland secretions onto skin surface In response to hormonal or nervous signal axoneme - ANSWER-core of cilia that is the structural basis for ciliary movement; (9x2+2) Core of microvilli - ANSWER-Just actin filaments basal lamina - ANSWER-basement membrane basal bar - ANSWER-terminal web, below the brush border connexin - ANSWER-gap junction protein glyocalyx - ANSWER- Serosa - ANSWER-mesothelium; serous membrane for sliding organs; Mesentery (intestine) - ANSWER-suspends intestines in the abdominal cavity gastrointestinal tract layers (outside to inside) - ANSWER-Mesentery (holds up the intestines in the abdominal cavity); serosa; loose connective tissue; Muscularis externa (longitudinal then circular), submucosa; Muscularis mucosae (aka muscularis interna); MuMucosa (with villi); lumen Muscularis externa - ANSWER-Two-layered smooth muscle layer (outer, longitudinal and inner circular) Submucosa - ANSWER-Layers of dense irregular cartilagenous connective tissues (DICCT) sitting between the muscularis externa and the muscularis mucosae (muscularis interna); contains nerves and glands (submucosal glands) Mucosa - ANSWER-3 innermost layers of the GI tract: the Epithelia, lamina propria, and muscularis mucosa (in to out) Lamina propria - ANSWER-Loose connective tissue layer between the epithelial lining and muscularis mucosae of the mucosa. Muscularis mucosae - ANSWER-Aka muscularis interna; Thin layer of smooth muscle cells that can impart some movement to the villi. Lymphoid nodules - ANSWER-Nodules can be anywhere: germinal epithelium; where infection may enter the body; take over for thymus when thymus involutes; may occur in Lamina propria and submucosa Mucosal glands (crypts of Lieberkuhn) - ANSWER-(Aka intestinal glands); fold of epithelium that form glands in the intestines. Cells of Aurebach's Plexus - ANSWER-Aka mysenteric plexus; collections of nerve cells; between two muscle layers (the longitudinal and circular layers of the muscularis externa) Plica circularis - ANSWER-Gross folds (can be seen by the naked eye) of intestinal wall; analagous to rugae of the stomach. In the large, red square. Relationship between the intestinal villi and crypts of Lieberkuhn - ANSWER-Villi are projections of the epithelium into the lumen for absorption, and the crypts are projections into the mucosa used for secretion. Parenchyma - ANSWER-active constituents of glands Mesothelium - ANSWER-epithelium lining body cavities Silver mesentery spread - ANSWER-This is a top view of simple squamous epithelia. Usually, silver stained epithelia stain in the substances that hold the cells together around the outside of the cells (The nuclei are probably stained with hematoxylin) Endothelium - ANSWER-simple squamous epithelial tissue lining blood vessels Parts of the kidney and what they look like (very general) - ANSWER-Cortex (like spaghetti) is on the outside; Medulla (striated and organized) inside the cortex and flows to renal pelvis; glomerulus (like little balls of cells in the cortex) Serous Demilune - ANSWER-Serous cells superficial to mucous secretory cells (in mixed glandular cells) that are shaped like crescents Types of sections - ANSWER-longitudinal, transverse (cross), oblique Transverse section - ANSWER-also called cross section;a cut along a horizontal plane, dividing the body or organ into superior and inferior parts oblique section - ANSWER-cuts made diagonally between the horizontal and the vertical planes Longitudinal section - ANSWER-cut through the long axis of an organ Zymogens - ANSWER-inactive versions of proteins (especially digestive proteins that become active in an acidic environment) Order of important organelles in a polarized cell - ANSWER-Basal membrane - basal end containing the nucleus - golgi ontop of nucleus - secretory granules moving toward apical portion of the cell - apical surface - duct Lipid droplet - ANSWER-Appears clear in the cell and hold fat (usually clear because the fat gets washed out during preparation; corpus luteum will look clear for the same reason) Onion root tip - ANSWER-Full of actively mitotic cells three tunics of the eye - ANSWER-fibrous (Sclera); vascular (choroid); and nervous (retina) Sclera - ANSWER-Outer layer of the eye; essentially mainly dense collagen fibers; white of the eye Choroid - ANSWER-between the retina and the scelera; it is pigmented with melanin and appears black; it is also vascular Cilliary body - ANSWER-Contains a ring of muscles that surround the lens and control its shape; it consists, in part, of the muscle that changes the shape of the iris. Microtubulin - ANSWER-It is a protein filament that makes microtubules How does periodic acid schiff work? - ANSWER-Periodic acid makes the alcohol into an aldehyde. The Schiff reagent binds the aldehyde to the fuschin (carmine; makes it magenta/fuschia) dye What stains the terminal web? - ANSWER-Eosin; it is very eosinophillic due to the basophillic cytoskeleton components. visceral peritoneum - ANSWER-It is another name for the serosa; the inner layer of the peritoneum that surrounds the organs of the abdominal cavity Example of a unicellular gland - ANSWER-goblet cells (Seen usually as a negative image because goblet cells secrete mucous) suderiferous glands (shape) - ANSWER-sweat glands (coiled, tubular gland) Intraepithelial gland - ANSWER-forms an indentation in the epithelia Sebaceous gland - ANSWER-oil-secreting gland in the dermis that is associated with hair follicles; they are alveolar glands proteonaceous - ANSWER-consisting of or containing proteins Major salivary glands - ANSWER-Parotid, sublingual (under tongue and secrete amylase and lipase), submaxillary (under jaw); meibomian glands - ANSWER-aka tarsal glands; glands found in the upper and lower edges of the eyelids that help lubricate the eye Different types of sweat glands - ANSWER-apocrine - open into hair follicle (axilary region aka armpit) eccrine - nor on hair follicles (also called merocrine); in palmar region, literally palm cerumen - ANSWER-earwax; yellow waxy material that lubricates and protects the ear canal Paneth cells - ANSWER-unicellular glands that secrete enzymes that kill bacteria; they can be seen with secretion granules; they are a type of intraepithelial gland How intestinal epithelia form microvilli and glands - ANSWER-Microvilli - Form from outgrowths of the epidermis Glands (aka crypts of Lieberkuhn) - invaginations of the epidermis create glands. Cells from the mid portion of the glands begin undifferentiated and then move up (toward the lumen) and differentiate. Tongue papillae - ANSWER-The almost rectangular structures on the tongue. Taste pore - ANSWER-an opening in the taste bud that lets saliva enter (are sub epithelial); there are 3 to 4 per papillae Testis - ANSWER-Exocrine glands that secrete spermatozoa Sperm wave development - ANSWER-Mitotically active wave of spermatogonia; primary spermatocytes (1 nuclear division); secondary spermatocytes (2 nuclear divisions); become differentiated spermatids that are released into the lumen At birth, what stage are oocytes in? At ovulation? At fertilization? - ANSWER-They are arrested at prophase I of meiosis I; then they complete meiosis I at ovulation; finally, they complete meiosis II upon fertilization. Primordial follicle - ANSWER-Oocyte arrested at meiosis I; has one layer of cells around it; as follicle cells develop they produce more and more estrogen (forms a positive feedback loop with luteinizing hormone) Primary Follicles - ANSWER-Follicles that are recruited for development; the flattened cells around the follicle become cuboidal and begin to divide Secondary Follicle - ANSWER-Two or more cuboidal cell layers; the oocyte also acquires a zona pellucida around it (which is very pellucida); also has theca cells (flattened cells around the follicle) Tertiary follicle - ANSWER-Aka Grafian Follicle; fluid creates a cavity in the follicle called an antrum; blood vessels also start to form Mammary gland development - ANSWER-1.) Form before 4 months 2.) At 4 months, 8-10 pairs of primordia (the lines become dotted) 3.) Nipples form from the dots depending on the animals (the dots that do not form nipples fade) 4.) Puberty - different ducts Duct differentiation of mammary glands - ANSWER-Ducts: undeveloped tubes prenatally; branching increases during puberty; secretory alveoli develop during pregnancy and finish developing during the third trimester. Parts of the eye from outside inwards - ANSWER-cornea, anterior chamber, iris, lens, posterior chamber, retina Mesentery - ANSWER-much white space (aereolar); very thin, coiled lines are basophillic elastic fibers that become coiled when they lose tension; collagen fibers are more eosinophillic (more pink); many different nuclei present What cells in the mesentery have irregular nuclei? - ANSWER-Macrophages What cells have long, oval nuclei in the mesentery - ANSWER-fibroblasts Adipose tissue (Two types) - ANSWER-Fat storage; - Brown (dense, dark,mitochondria-filled); thermogenic (abundant in humans before one year of age); many droplets of fat (multilocular); very eosinophillic - White (whitish to yellowish); look like negative images; nucleus off to the side; honeycomb appearance; unilocular; one, large lipid drop What stain is used for mast cells? - ANSWER-Toluidine blue; the dye polymerizes when it binds to the mast cells and exhibits metacromasy (it becomes purplish from blue) Reticular connective tissue - ANSWER-Reticular connective tissue is found around the kidney, liver, the spleen, and lymph nodes; it stains well with silver nitrate; Tendons (function and makeup) - ANSWER-They connect muscle to bone; parallel bundles of dense, regular, collagenous connective tissue forms the tendons. There may also be tenocytes (fibroblasts in the tendons) Aponeuroses - ANSWER-Fibrous or membranous sheet connecting a muscle and a bone (layer in a tendon) Epitendineum; peritendineum; endotendineum - ANSWER-Epitendineum - A surrounding connective tissue of the entire tendon. It is made of dense irregular collagenous connective tissue. Peritendineum - separates the tendon into fascicles (DICCT) Enddotendineum - surrounds tendon cells, blood vessels, and nerves in the tendon; it is made of loose connective tissue Ligaments (function and difference between 2 types) - ANSWER-They connect bones to bones; The two types are white (collagenous ligaments with parallel budles of collagen; between rows of endotendinum from fibroblasts) and yellow (elastic ligaments with elastic fiber bundles interspersed among collagen bundles ligamentum nuchae - ANSWER-an elastic ligament that connects the vertebrae of the neck to the skull; it is a classic example of elastic (yellow) ligaments Dense Irregular Connective Tissue - ANSWER- General features of connective tissues - ANSWER-1.) Maximum amount of extracellular material and minimum number of cells (except adipose tissue and bone marrow) 2.) Cells produce an extracellular matrix 3.) Cells are typically derived from the mesoderm. 4.) The extracellular matrix (ECM) consists of ground substance and fibers 5.) Moderate regenerative capacity Ground Substance - ANSWER-amorphous, water based component of the extracellular matrix that contains proteoglycans, glycosaminoglycans (GAGs), and adhesion proteins General function of connective tissues - ANSWER-Mechanical - binding, supporting, isolation, vessel support, packing, shock absorbing, etc. Vital - Nutritive reservoirs (adipose, protein, minerals); protective (phagocytosis, wound healing, and immunization) Cevelopmental - necessary for immunological organ differentiation (mesenchyme as an inducer) Three non-specialized types of adult connective tissue - ANSWER-1. Loose (areolar) CT - subepithelial, more ground substance than fibers (mesenteric spreads, epithelial slides 2.) Dense Regular Collagenous Connective Tissue (Tendons and Ligaments) 3.) Dense Irregular Collagenous Connective Tissue (DICCT) - in dermis and capsules embryonic connective tissue - ANSWER-mesenchyme (first mesodermal derivative, spindly cells, derives all CT except neural crest derivatives) and mucous connective tissue (gelatin-like with spindly (fusiform) cells, wispy collagen, and Wharton's jelly)) Specialized types of connective tissues - ANSWER-1.) Elastic - where compliancy is needed (lungs, arteries, etc.) 2.) Adipose 3.) Cartilage (chondrocytes) - shock absorbing 4.) Bone 5.) Cardiovascular system Lymphatic System What is Mallory's trichrome useful for staining in connective tissue? - ANSWER-It stains collagen blue. Is aniline blue acidic or basic? - ANSWER-It is acidic; that is why it can stain collagen (collagen is basic/acidophillic) Hyaline Cartilage - ANSWER-Articular cartilage; fairly uniform matrix; present on vertebrae (endochondral skeleton),tracheal rings, and bronchiolar cartilage Elastic cartilage - ANSWER-auricular cartilage (supporting pinna of inner ear); epiglottis; larynx; tip of nose (look for elastic fibers) Fibrocartilage - ANSWER-cartilage that contains fibrous bundles of collagen, such as that of the intervertebral disks in the spinal cord, annulus fibrosis, and meniscus (in knee) Perichondrium - ANSWER-Dense irregular connective tissue membrane covering cartilage; inner cellular perichondrium -produces new chondrocytes inwards (mesenchyme- chondroprogenitor cells-chondroblasts-chondrocytes) and the outer fibrous perichondriu How cartilage grows - ANSWER-isogenous groups - chondrocytes in lacunae mitose to create groups of cells in a singular lacuna that produce extracellular matrix to separate themselves. Perichondrial (appositional) - cells of the perichondrium produce chondrocytes and on the surface of the cartilage Is the cartilage matrix basophillic or acidophillic? - ANSWER-Basophillic (gag rich) Interstitial v. territorial matrix - ANSWER-Interstitial matrix - matrix between lacunae Territorial matrix - basophillic rim around a lacuna Lacuna - ANSWER-small cavity in bone or cartilage that contain osteocytes or chondrocytes (respectively) Chondroblast - ANSWER-immature cartilage cell (responsible for matrix production); it will become a chondrocyte once it is surrounded by a fullly formed lacuna. Knee joint microscope - ANSWER-This may be a mallory's trichrome, since the part where there would be collagen (in the cartilagenous areas) is blue. The knee bone itself has surfaces with hyaline cartilage, and the little triangular wedges in between are fibrocartilage of the menisci. Cross section of ligamentum nuchae - ANSWER-nuclei are fibroblasts, lighter pink (might not be visible on the image) are elastic fibers, and darker pink are cartilage fibers. Bone v. Bones - ANSWER-Bone - is a tissue Bones - organs Long bones - ANSWER-Bones that are longer than they are wide (ex. femers, tarsals, etc.) flat bones - ANSWER-bones of the ribs, shoulder blades, pelvis, and skull; thin, flattened bones. Sesamoids - ANSWER-Bones located within soft tissue; ex. knee cap Epiphysis - ANSWER-End of a long bone Diaphysis - ANSWER-shaft of a long bone Medulla of bone - ANSWER-Cavity of the bone that houses marrow Types of marrow - ANSWER-Yellow (or white) - fat storing Red - blood forming Spongy bone - ANSWER-Layer of bone tissue having many small spaces and found just inside the layer of compact bone; it is easily seen in the epiphyses. trabeculae - ANSWER-supporting bundles of bony fibers in (spongy) bone Cortex of bone - ANSWER-outer portion of the bone; it is formed out of what is called compact bone Does cartilage become bone? - ANSWER-No; it just acts as a scaffolding so that bone may replace it. Proximal - ANSWER-Closer to the point of attachment Distal - ANSWER-farther from the origin of a body part or the point of attachment of a limb to the body trunk Epiphyseal plates - ANSWER-Plates which allow for growth of long bone during childhood. They produce cartilage that gets replaced by bone Metaphysis - ANSWER-where diaphysis and epiphysis meet; also the location of the growth plate. Bone growth is analagous to cartilage - ANSWER-mesenchyme gives rise to osteoprogenitor cells (instead of chondroprogenitor cells), which give rise to osteoblasts (instead of chondroblasts), which become osteocytes (instead of chondrocytes) Osteoblasts - ANSWER-The only cells that build new bone (they do not divide) Lacuna of osteocytes - ANSWER-perforted to enable processes to form that connect osteocytes to other cells (the processes fit inside canaliculi). This gives osteocytes a stellate (star-like) appearance under high magnification Osteocytes - ANSWER-a bone cell, formed when an osteoblast becomes embedded in the matrix it has secreted. They are capable of breaking down bone. Osteoclast - ANSWER-multinucleate cell that secretes acids and enzymes to dissolve bone matrix (made of a group of macrophages) Bone formation v. resorption - ANSWER-Both happen constantly; formation is done by osteoblasts and is the dominant process in younger individuals; resorption is done by osteoclasts and osteocytes and becomes more dominant in older individuals (why people shrink when they get old) Decalcification (bone preparation) - ANSWER-Removes mineralized parts of bones in order to see the organic part Circumferential lamellae - ANSWER-a bony lamella that encircles the outer or inner surface of a bone ground bone - ANSWER-Take a slice of bone and grind it so that a thin layer is formed. Osteons - ANSWER-Structures in bones that carry the blood supply (they are concentric circles of lamellae) Interstitial lamellae - ANSWER-lamellae between osteons Haverisan system - ANSWER-An osteon; Compact bone matrix is organized into structural units of bone Radiograph of bone - ANSWER-Lighter areas indicate more dense bone, while darker areas indicate less dense bone Nutrient foramen - ANSWER-small opening in the middle of the external surface of the diaphysis, through which an artery enters the bone to provide nourishment; originally, it is in the middle of the diaphysis, but the distal epiphyseal plate causes the distal end of the bone to grow faster. Diploe - ANSWER-spongy layer in the cranium that seem to form bridges between the two layers of bone. New lacunae tend to be ________ than old lacunae. - ANSWER-Flatter; due to resorption. Periosteum - ANSWER-A dense fibrous membrane covering the surface of bones (except at their extremities) and serving as an attachment for tendons and muscles. Spicules - ANSWER-thin plates in the epiphyses that make up the spongy bone Endosteum - ANSWER-lines the medullary cavity; thinner than the periosteum Howship's lacunae - ANSWER-a groove or cavity usually containing osteoclasts that occurs in bone which is undergoing resorption Volkmann's canals - ANSWER-channels lying at right angles to the central canal, connecting blood and nerve supply of the periosteum to that of the Haversian canal Haversian canal - ANSWER-one of a network of tubes running through compact bone that contains blood vessels and nerves (Run longitudinally along bone) Histiocyte - ANSWER-name of a macrophage in connective tissue. Immersion v. Perfusion - ANSWER-Immersion - physically submerging the sample in the fixative Perfusion - using the heart of the animal to distribute saline, then the fixative (very long process) Wandering cells of connective tissue - ANSWER-Short lived; lymphocytes, plasma cells, monocytes, and granulocytes Indigenous cells of connective tissue - ANSWER-Mast cells; fat cells (adipocytes); fibroblasts; histiocytes; adult stem cells Neutrophils - ANSWER- Organization of a collagen bundle (from collagen molecule up) - ANSWER-Molecule of collagen - trimer (3 collagen molecules) - fibrils - fibers - bundles