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150 Cards in this Set

  • Front
  • Back
LEVELS OF HIERARCHY (small to large)
- Molecular Level
- Cellular Level
- Tissue Level
- Organ Level
- Organ System Level
- Organism Level
- Population Level
TERMINALLY DIFFERENTIATED/SPECIALIZED CELLS
- have very specific structural features
- Biochemical features
- A very specific function in the organism
CELLULAR COMPARTMENT
- composed of one or more terminally differentiated Specialized Cell
EXTRACELLULAR COMPARTMENT
- composed of extracellular matrix components (ECM) and tissue fluid)
- Located outside and between cells
- intercellular materials or extracellular materials
FIBROUS/FORMED COMPONENTS
- extracellular matrix component
- composed of specific proteins and glycoproteins
- exists in structurally/morphologically distinct form
- collagenous fibers, elastic fibers
ECM COMPONENTS
- Fibrous/formed components or amorphous components
- produced by cells from the cellular compartment
- holds or binds cells together
- have mechanical properties
TISSUE FLUID
- consists mostly of water containing dissolved gasses, solutes, and suspended materials (proteins, glycosylated proteins, lipids, lipoproteins)
- percoltes around extracellular spaces
- Lost during speciman processing
DEFINITION OF TISSUE
- A tissue consists of structurally similar cells with similar functions that are present (along with their associated ECM components and tissue fluid) in the same location at the same time.
AMORPHOUS COMPONENTS
- ECM
- composed of glycosaminoglycans (GAG) and aggregates of GAGs and proteins
- do not exist in a structurally/morphologically distinct form
PARENCHYMA TISSUE
- tissue type that is essential for organ function
- usually the predominant tissue type in an organ
STROMAL TISSUE
- the tissue that holds the functional elements together in an organ
- could form the large framework of an organ
FIXATION
- initial procedure
- terminates cellular metabolism, prevents autolysis, immobilizes cellular and extracellular components within tissues, and also kills microorganisms
- preserves structure of cells, tissues, and organs
- must begin immediately after euthanasia
- use fixatives (aldehydes, alcohols, heavy metals)
- small molecules are not preserved but large ones are.
- The smaller the specimen the faster the fixative will penetrate the specimen and react with or alter components
ALDEHYDES
- formaldehyde (1 group)
- Glutaraldehyde (2 aldehyde groups)
- reacts with aa and cross link proteins and potein contianing macromolecules
- reacts with lipids
- Because glutaraldehyde has 2 aldehyde groups more proteins and protein containing macromolecules will be cross linked following fixation
- Glutaraldehyde used in TEM or SEM
Formaldehyde used in LM
ALCOHOL
- ethanol
- methanol
(contain acetic acid)
- Alter tertiary structure of proteins and denature proteins so they can't function
- Used in LM
HEAVY METALS
- osmium tetroxide
- reacts with lipids and proteins and cross links them
- preserves/ fixes lipids
- Used in TEM or SEM
FIXATION BY IMMERSION
- submerge the excised specimens in fixative
FIXATION BY VASCULAR PERFUSION
- introduce fixative into specimen via blood vessels prior to removing specimen from animal
DEHYDRATION
- initial procedure
- replace water with dehydrating agent to prepare specimen for infitration with embedding material (LM & TEM) or solvent/drying agent (SEM)
- Drying agents are: ethanol, other alcohols, acetone
SEM ADDITIONAL PROCEDURES
- infiltrate with solvent Freon after dehydration
- Critical point dried
- Coat with heavy metal like gold
INFILTRATION AND EMBEDDING
- additional procedure with specimens under LM or TEM
- Specimen is infiltrated with embedding material in order to replace alcohol with embedding medium
- Specimen is placed in small mold filled with embedding medium and allowed to solidify.
PARAFFIN WAX
- embedding media with LM
- Need organic solvents because it is not alcohol-miscible
- Use following dehydration and during initial infiltration
- place in small mold and allow molten paraggin to solidify as it cools in room temperature
- used for surgical and autopsy specimens as well as specimens prepared in histology labs of biological supply companies
- relatively inexpensive
GLYCOL METHACRYLATE (GMA)
- Embedding media at LM
- alcohol-miscible so no organic solvent needed
- can also use another plastic regin
- Place in a mold and refrigerate for 24-48 houts until GMA solidifies
- used for research specimens prepared in histology labs of some biological supply companies
- relatively expensive
EPOXY RESIN
- embedding material for TEM
- some are alcohol-miscible so no organic solvents needed
- Plastic resins that aren't alcohol miscible must use an intermediate solvent following dehydration and during initial infiltration with plastic resin
- Place in small mold and put in ove (40-60 celsius) for 24-48 hours until epoxy resin solidifies
- used for research specimens
- relatively expensive
SECTIONING
- cut with a microtome (LM) or a ultramicrotome (TEM)
- Section into thin slices using a metal or glass knife for LM or glass or diamond knife for TEM.
- Paraffin and GMA is cut using a microtome and allowed to dry on microscope slide
- Epoxy sections are cut with a ultramicrotome and allowed to dry on a metal grid of copper
STAINS FOR EXPOXY SECTIONS (TEM)
- use uranyl acetate and lead citrate
STAINS FOR LIGHT MICROSCOPY
- dye molecules are ionized and macromolecules and extracellular components in specimens are ionized so these groups will react with each other and give color
- Use anionic (acidic) dyes and Cationic (basic) dyes
- The greater the charge density the greater the intensity of staining
ANIONIC/ACIDIC DYES
- acid fuchsin
- aniline blue
- eosin
- Orange G
- anion have a negative charge and bind to positively charged groups (amino groups).
- acidophilia
- the protein containing cellular and tissue components that stain with anionic dyes are exhibiting acidophilic staining (pink or red)
CATIONIC/BASIC DYES
- Azure A (dark blue)
- Hematoxylin (dark blue or purple)
- Methyl green
- Methylene blue
- Nuclear fast red
- Pyronine (red)
- Toluidine
- basophilia- cation is positively charged and attaches to a negatively charged group like nucleic acids, complex acidic polysaccharides (glycosaminoglycans in amorphous components), and ionized carboxyl groups.
- Basophilic staining is blue to purple
PERIODIC ACID-SCHIFF (PAS)
- stains polysaccharides and carbohydrate containing macromolecules
VERHOEFF
- distinguish between elastic fibers and collagen fibers
GIEMSA AND WRIGT
- stains blood smears
SILVER-CONTAINING STAINS
- distinguish reticular fibers
- Distinguishes nerve cells and tissue
In Situ LOCALIZATION OF ENZYMES
- suitable substrate for the enzyme that will yield a colored precipitate at the site of the enzyme
In Sity LOCALIZATION OF SPECIFIC PROTEINS
- use antibodies that react selectively with that specific protein
- the antibodies have reporter molecules (flourescent dye) to allow visualization of the antibody
In Situ LOCALIZATION OF SPECIFIC MRNAs
- use DNA probes that react with the specific mRNA
- DNA probes have a reporter molecule to allow visualization of the probe after it binds to the mRNA
NUCLEAR COMPARTMENT
- contains the nuclear envelope (with nuclear pores)
- basophilic staining because of high content of nuclei acids
- chromatin
- nucleolus
- Nucleoplasm
NUCLEAR ENVELOPE
- TEM
- Two parallel membranes separated by a perinuclear space
- Has Nuclear pores (annuli) that allow passage of material between nuclear compartment and cytoplasmic compartment
- Fibrous nuclear lamina on inner surface of nuclear envelope that allows scaffolding for nuclear components like chromatin
CHROMATIN
- TEM
- has DNA, histones, and nonhistone proteins
- 2 types are euchromatin and heterochromatin
EUCHROMATIN
- dispersed or extended
- lightly stained because less phosphate groups
- actively involved in mRNA & tRNA synthesis
- Tanscriptionally active form of chromatin
HETEROCHROMATIN
- condensed or coiled
- Darkly stained because of the increase in phosphate
- not involved in mRNA & tRNA synthesis
- transcriptionally inactive form of chromatin
NUCLEOLUS
- TEM and LM
- Very basophilic and spherical
- Nucleolar Organizer Region (NOR)- chromosomal region that contains the gene sequences for ribosomal RNA
- The presence of the nucleolus and chromatin are indicative of the extent of production of ribosomes and how transcriptionally active the cell is.
- The more euchromatin and the more prominent the nucleolus the mmore extensive the transcriptional activity meaning there are more ribosomes.
NUCLEOPLASM
- gel in which chromatin and nucleolus are suspended
- TEM level
- Unstained regions
CYTOPLASMIC COMPARTMENT
- nuclear envelope to outer boundary/surface of cell
- acidophilic staining in most cells due to high protein content of cytoplasm
- organelles and inclusions
- cytoplasmic matrix
- structures are only visualized at TEM level
MITOCHONDRIA
- TEM
- rod shaped or elongated membrane bound structures in a longitudinal section
- spherical membrane bound structure in a transverse section
- outer membrane surrounds inner folded membrane of cristae
- exhibit acidophilic staining because of protein
- Iron hematoxylin stain allows mitochondria to be detected at the LM level
- major site of ATP production during aerobic respiration
- site of many other metabolic activities
RIBOSOMES
- TEM
- very small dark dots
- when in groups are called polyribosomes
- composed of ribosomal RNA molecules and ribosomal proteins
- Detectable at LM level with basophilic staining
- site of polypeptide synthesis
- Have free and attached ribosomes
FREE/UNATTACHED RIBOSOMES
- polypeptides are destined for internal use
- not packaged into membrane bound vesicles
- polypeptides are cytosolic enzymes, ribosomal proteins, cytoskeletal proteins, proteins found in mitochondria and peroxisomes
ATTACHED RIBOSOMES
- attached to ER
- Polypeptides are packaged into membrane bound vesicles
- destined for cell membranes
ENDOPLASMIC RETICULUM
- TEM
- a network or meshwork of membrane bound cisternae/flattened sacs, tubules, and or vesicles
- RER and SER are interconnected with each other and the nuclear envelope, golgi apparatus, and plasmalemma
ROUGH SURFACED ENDOPLASMIC RETICULUM/ ROUGH ER
- has ribosomes
- In translation newly synthesized polypeptide chains pass into the lumen of the cisternae where glycosylation of the polypeptide chains occur
- After translation the glycosylated polypeptide chains pass into the golgi
- Granular basophilic staining at LM level
- polypeptides are destined for cell membranes, lysosomes, secretory granules
SMOOTH SURFACED ENDOPLASMIC RETICULUM/ SMOOTH ER
- no ribosomes
- agranular light acidophilic staining at LM level (protein in ER)
- indicates lipid synthesis, HCL synthesis, calcium ion storage, detoxification or alteration of molecules to less toxic forms
GOLGI APPARATUS
- TEM
- aggregations of stached, membrane bound saccules or cisternae and associated smaller transport vesicles
- have connections with both RER and SER
- May be detected at LM level with DaGano silver method or its a clear region in basophilic cytoplasm (H&E) called negative Golgi image (neurocytes)
- processing and packaging glycosylated polypeptides
- plays a role in movement of glycosylated polypeptides, glycoproteins, and lipoproteins into different cytoplasmic subcompartments
- Destined for cell membranes, lysosomes, or secretory granules
LYSOSOMES
- expect to see in every cell
- TEM and LM (larger ones)
- located throughout cytoplasm
- Formed by golgi
- membrane bound vesicles with about 40 acid hydrolases (enzymes in acidic conditions)
- Found in cells that function in phagocytosis like macrophages, neutrophils, eosinophils
- Primary lysosomes are newly formed by the golgi
- Secondary lysosomes (phagosomes) are formed when primary lysosomes fuse with either phagocytic vesicles or endosomes. These are larger and break down the ingested materials
MODIFIED LYSOSOMES
- non-acid hydrolases and or other types of enzymes are present
ACID HYDROLASES
- function in intracellular or extracellular digestion
- digests materials brought into cells by phagocytosis or endocytosis/pinocytosis
- digests cellular organelles or entire cell
- digests extracellular matrix components following release of acid hydrolases from cell
SECRETORY GRANULES/SECRETORY VESICLES
- TEM or LM (larger ones)
- darkly stained
- formed by golgi
- membrane bound vesicles containing material destined for export from cell via sectrion
- stores large amounts of secretory products
- Acidophilic granules at LM level
- Localized in cytoplasm and its position is indicative of where the products will leave the cell.
PEROXISOMES/MICROBODIES
- TEM or LM with selective staining
- membrane bound vesicles containing about 20 oxidative enzymes
- found in most cells but even more are found in the liver and kidney
- similar to the appearance of lysosomes
OXIDATIVE ENZYMES
- beta oxidation enzymes, D-amino acid oxidase, catalase, urate oxidase, alcohol dehydrogenase, and various peroxidases
- beta oxidation of fatty acids
- alcohol metabolism
- breakdown of hydrogen peroxide generated in other enzymatic reactions
CYTOSKELETON
- found in most cells
- centrioles > microtubules > intermediate filaments > microfilaments
MICROTUBULES
- TEM and LM with special staining techniques
- long to very long hollow cylindrical structures
- composed of protein subunits, alpha and beta tubulin, arranged in repeating units
- helps maintain cell shape
- role in intracellular ransport
- found in axonal process of neurons and mitotic apparatus of cells undergoing cell division
CENTRIOLES
- TEM
- short cylindrical structures comprized of microtubules
- nine triplets of 3 fused tubulin containing microtubulelike structures
- associated with mitotic apparatus in dividing cells
MICROFILAMENTS
- TEM and LM with special stianing techniques
- long, solid filamentous structures
- composed primarily of actin but myosin is intimately associated
- associated with cell junctions
- contractile properties of cells
- characteristic of muscle cells with extensive contractile functions
INTERMEDIATE FILAMENTS
- TEM and LM with special staiing techniques
- long, solid filamentous structures
- one intermediate filament protein per cell type
- examples are desmin, cytokeratin/prekeratin
- associated with cell junctions
- internal support for cells
LIPID DROPLETS/FAT DROPLETS
- inclusions
- LM and TEM levels
- many smaller lipid droplets or one single large lipid droplet
- storage form of lipid materials like adipocytes/lipocytes and hepatocytes
GLYCOGEN GRANULES/GLYCOGEN STORAGE GRANULES
- inclusion
- TEM or LM with special stains
- darkly stained in TEM
- free cytoplasmic granules organized in clusters
- storage form of glucose (hepatocytes)
PIGMENT GRANULES
- inclusion
- LM and TEM levels
- melanin containing pigment granules associated with skin and eye
- type of pigment varies with cell type
CYTOPLASMIC MATRIX
- gel that occupies regions between organelles and inclusions and suspends them
- at TEM level it is lightly stained
- location of ions, monomers used to synthesize macromolecules, many soluble cytosolic enzymes
CELL SURFACE
- plasmalemma/plasma membrane
- superficial cytoplasm
- characterized by Cell surface features/ modification that are involved in holding cells together in groups or in intercellular communication
PLASMALEMMA/PLASMA MEMBRANE
- outer limiting membrane of cell
- TEM
- organized as a lipid bilaryer and outer glycocalyz
- functions in movement of materials in and out of cells
LIPID BILAYER
- TEM level as two dark lines separated by a clear region
- composed of phospholipids, cholesterol, and proteins
- contains transmembrane proteins/integral proteins, and peripheral proteins
TRANSMEMBRANE PROTEINS/INTEGRAL PROTINS
- glycoproteins (oligosaccharide chains)
- extend through the entire lipid bilayer
PERIPHERAL PROTEINS
- glycoproteins (oligosaccharide chains) or proteoglycans (protein-polysaccharide complexes)
- do not extend through the entire lipid bilayer
- located on the inner side or external side of the lipid bilayer
MEMBRANE PROTEINS
- glycoproteins and proteoglycans
- other functional roles like structural, enzymatic, active transport pumps, receptors, transmembrane channels, cellular adhesion/attachment
GLYCOCALYX
- cell coat
- fuzzy coat on extracellular/ external side of lipid bilayer
- consists of oligosaccharide side chains of transmembrane glycolipids and glycoproteins and polysaccharide chains of proteoglycans
- involved in cellular recognition and cellular adhesion
SUPERFICIAL CYTOPLASM
CELL CORTEX
CORTICAL CYTOPLASM
- cytoplasmic region immediately inside the plasmalemma
- more rigid then the rest of the cytoplasm
- contains cytoskeletal components (microfilaments, intermediate filaments, sometimes microtubules)
- contains ribosomes, ER, and cytoplasmic matrix/cytosol
- no larger organelles or inclusions
- contains pinocytotic vesicles (small), phagocytotic vesicles (large), endosomes (small), secretory granules (exocytosis)
MICROVILLI
- TEM (individual) and LM (numerous)
- forms brush border/striated border
- small finger-like projections from cell surface
- contains microfilaments and cytoplasmic matrix
- involved in absorption of solutes
- treatly increases surface area of cells available for uptake of solutes from lumen
STEREOCILIA
- TEM (individual) or LM (numerous)
- long finger-like projections from cell surface
- much longer than microvilli and cilia and may be branched
- contains microfilaments and cytoplasmic matrix
- involved in absorption and transduction of sensory stimuli
CILIA
- TEM (individual) and LM (numerous)
- long finger-like projections from cell surface
- contains MICROTUBULES and cytoplasmic matrix
- Microtubules are in a 9 pair plus 2 arrangement with the outer 9 pair joining the basal body to the base of the cilium
- move secretions and particulate matter past the cell
- comprise sensory structures
FLAGELLA
- larger and more complex then cilia
- 1 flagellum occurs per cell in vertebrates
- move the cell through the environment like sperm
INFOLDINGS
- TEM
- cell surface projects into the interior of the cell
- increases cell surface for exchange of materials (proximal and distal convoluted tubules of nephrons)
CELL JUNCTIONS
- TEM
- plasma membranes of adjacent cells are modified for various functions
- holds cells together
- allows cell to cell communication
- prevents movement of material sthrough extracellular space between cells
PERICELLULAR COMPARTMENT
- located immediately outside and adjacent to the cell surface
- contains extracellular matrix components, tissue fluid, and basal lamina
COLLAGENOUS FIBERS
- fibrous formed ECM components
- composed of collagen a glycoprotein
- appears acidophilic
- Large fibers detected at LM level
- Fibroblasts to Procollagen to microfibrils to fibrils to fibers
- parallel bundles of collagen fibrils
- microfibrils at TEM level
- fibroblasts are the predominant collagen forming cell type
- Procollagen is collagen polypeptides that organized in three and secrete microfibrils
ELASTIC FIBERS
- Fibrous/Formed ECM component
- Elastin is central core surrounded by fibrillin
- forms fine microfibrils
- appears acidophilic
- TEM and LM
- formed by several different cell types
GLYCOSAMINOGLYCANS (GAGs)
- amorphous ECM component
- large polysaccharides consisting of repeating disaccharide units
- has sulfated or carboxylic acid side chains
- made groups are hyaluronan/hyaluronic acid, chondroitin sulfate and dermatan sulfate, heparan sulfate and heparin, keratan sulfate
- negative charged groups show basophilic staining
PROTEINS AND GLYCOPROTEINS
- amorphous ECM components
- fibronectin, laminan, tenascin, osteopontin, entactin/Nidogen
PROTEOGLYCANS
- consist of GAGs assembled on a core protein to form very large molecules
- aggrecan, decorin, perlecan, syndecan, versican
PROTEOGLYCAN AGGREGATES
- proteoglycans assemble onto a hyaluronic acid molecule to form a complex supermolecule that have a larger volume than mitochondria
RECEPTORS FOR ECM COMPONENTS (INTEGRIN RECEPTORS)
- bind directly or indirectly to collagen, fibronectin, laminin
- hold ECM components (in the pericellular compartment) in close proximity to the cells
- transmembrane glycoproteins
- made of alpha integrin chain/subunits and beta integrin chain/subunit, cytoplasmic tail of beta subunit coupled to actin filaments via linker proteins
BASAL LAMINA/ EXTERNAL LAMINA
-TEM layer
- thin layer of ECM components
- modified cell junctions anchor it to cells
- composed of very fine meshwork of type IV collagen, several glycoproteins, and proteoglycans rich in heparan sulfate and chondroitin sulfate
- also contains type VII collagen
- basal lamina in epithelial tissue and secreted by epithelial cells
- external lamina in muscle cells and schwann cells of nervous tissue
DERIVATION OF EPITHELIAL TISSUE
- embryonic development
- somatic ectoderm and endoderm
- some from somatic mesoderm
DERIVATION OF SECRETORY EPITHELIAL TISSUE
- embryonic development
- from developing sheet epithelia that extend into the underlying adjacent tissue
- may be attached to epithelia or not.
HOW SECRETORY EPITHELIA EXIST
- as individual cells or small groups of cells integrated into sheet epithelia
- multicellular clusters in connective tissue
- extensive large multicellular clusters forming glands
APICAL DOMAIN/SURFACE
- free surface of tissue that is exposed to air filled spece or fluid filled space
- characterized by cilia, microvilli, or stereocilia
BASAL DOMAIN/SURFACE
- opposite the natural free surface
- adjacent to connective tissue and basement membrane
- characterized by basal infoldings
LATERAL DOMAIN/SURFACE
- in contact with adjacent epithelial cells
- characterized by cell junctions and infoldings
- where the cells actually come together
TRANSITIONAL SHEET EPITHELIUM
- periodic distention or stretching
- also called urothelium
- thickness of epithelium and shape of cells vary
APICAL, BASAL, LATERAL DOMAIN/SURFACE MODIFICATIONS OF CELLS OF SIMPLE OR PSEUDOSTRATIFIED SHEET EPITHELIUM
- Microviili- forms a bush border on apical
- Stereocilia- on apical
- Cilia/flagella- on apical
- infoldings- on basal, lateral , or apical
OCCLUDING JUNCTIONS
- Zonula Occludens/ZO
- plasmalemmas of adjacent cells are joined through adhesion of transmembrane proteins and associated proteins in superficial cytoplasm
- Belt like regions so there is no intercellular or extracellular space
- Occludins and claudins are the transmembrane proteins
- restricts the passage of materials through the intercellular/extracellular space between lateral domains of cells
ANCHORING JUNCTIONS/ ADHERING JUNCTIONS
- zonula adherans and macula adherens
ZONULA ADHERENS
- belt-like regions
- plasmalemmas of adjacent cells are joined together by E-cadherin
- adjacent cells are separated by a uniform space
- microfilaments associate with cytoplasmic face of plasmalemmas
MACULA ADHERENS
- spot-like regions
- plasmalemmas of adjacent cells join together
- dense material in intercellular space
- intermediate filaments are intimately associated with the cytoplasmic face of the plasmalemmas
CALCIUM DEPENDENT CELL-CELL ADHESION MOLECULES (CAMS)
- E-cadherin
- desmocollin
- desmoglein
- responsible for joining the plasmalemmas of adjacent cells
- cytoplasmic tail of glycoproteins i sassociated with linker proteins on cytoskeltal structures
COMMUNICATING JUNCTIONS
- Macula communicans
- spot like
- plasmalemmas of adjacent cells join together
- cells are separated by a narrow gap
- Connexins are the transmembrane proteins and produce structures called connexons
- connexons form continuous open channels between cells
- allows inorganic ions and small water soluble molecules to pass
- Facilitate intercellular communication
JUNCTIONAL COMPLEX
TERMINAL BAR
- occluding junctions and adhering junctions arrange on lateral cell surfaces
- ZO located at near apical edge of cells
- ZA located below ZO
- MA located below ZA
- creates a selective permeable barrier
- cells have to enter and exit the cell through the lateral or basal surfaces.
BASEMENT MEMBRANE
- basal surface of entire sheet epithelium
- At LM level when periodic acid Schiff reaction (PAS) staining occurs
- Thin basal lamina and thick reticular lamina
HEMIDESMOSOMES
- anchored basal lamina to the basal surface of epithelial cells
RETICULAR LAMINA/LAMINA RETICULARIS
- TEM
- closely packed reticular fibers (type III collagen) embedded in glycosaminoglycnas
EXOCRINE SECRETORY EPITHELIAL TISSUE
- releases secretory products on sheet epithelium
- exhibit polarization of intracellular components
- Exocrine glands- structures composed of exocrine secretory epithelial tissue
- widespread distribution in body
INTRINSIC EXOCRINE GLANDS
- exocrine glands exist as small parts of larger organs
- sweat glands of skin
- gastric glands of stomach
EXTRINSIC EXOCRINE GLANDS
- exist as the predominant tissue type of organs
- salivary glands
- exocrine portion of pancreas
ENDOCRINE SECRETORY EPITHELIAL TISSUE
INTERNAL SECRETING SECRETORY EPITHELIAL TISSUE
- separates from epitelial sheet
- cells release secretory product into the tissue fluid so it will diffuse into the connective tissue. Once there it enters the capillaries and is carried throughout the body in blood
- Endocrine glands are structures completely composed of endocrine secretory epithelial tissue
- more limited distribution in body
- Thyroid gland
- parathyroid gland
- endocrine portion of pancreas
INTRAEPITHELIA
- totally integrated into the sheet epithelium
- secretory product is released on the suface of the surrounding sheet epithelium
- most commonly the secretory units are unicellular
EXTRAEPITHELIAL
- secretory units don't exist in sheet epithelium
- secretory product is released onto the surface of sheet epithelium located away from from the secretory units
- always multicellular
- nonsecretory cells form ducts that connect the secretory units to the sheet epithelium
SEROUS SECRETING CELLS
- enzymatic proteins
- thin and watery
- basally located nuclei
- contains more euchromatin than haterochromatin and granular cytoplasm
MUCOUS-SECRETING CELLS
- secretory products are heavily glycosylated
- thick and viscous
- provides protection
- more heterochromatin than euchromatin
LIPOID SECRETING CELLS
- oily and provide lubrication
- centrally located nuclei
- more heterochromatin than euchromatin and cytoplasm that appears extracted
MEROCRIN/ECCRINE
- secretory granules released from apical surface via exocytosis
APOCRINE
- apical part of cell is pinched off as secretory product
HOLOCRINE
- entire cell is released as a secretory product
- secretion of oil by sebaceous glands of skin
DERIVATION OF BLOOD CELLS
- derived from the somatic mesoderm of the developing embryo
HOW BLOOD IS UNIQUE
- exists as a fluid
- restricted in location within the body
- functions in extravascular locations (exits blood vessels and migrates into other tissues)
ERYTHROCYTES/ RED BLOOD CELLS
- functions within blood vessels
- Resident cells of blood
- spherical biconcave discs
- anucleated in mammals
- cytoplasm exhibits acidophilic staining because of hemoglobin
- Few organelles are present
- Life span is 120 days
- carries 80-90% of oxygen in blood and a small amount of carbon dioxide
LEUCOCYTES// WHITE BLOOD CELLS
- 2 types are granulocytes and agranulocytes
- carry out functions in extravascular locations
- Transient cells of blood
GRANULOCYTES
- contain lobed nucleus
- numerous cytoplasmic granules
- neutrophils
- eosinophils
- basophils
AGRANULOCYTES
- non-lobed nucleus
- relatively few cytoplasmic granules
- lymphocytes
- monocytes
THROMBOCYTES/PLATELETS
- functions within blood vessels
- resident cells of blood
- small round or oval enucleated cytoplasmic cellular fragment
- occurs singly and in clusters
- dervied from megakaryocytes in bone marrow
- 2 different zones
BLOOD PLASMA
- makes up extracellular compartment (tissue fluid)
- consists of water, dissolved solutes (ions, nutrients, gases, metabolic waste products, hormones), and suspended macromolecules (proteins, lipoproteins, glycoproteins)
- not present in histological preparatioinis
- lumne of blood vessels are lightly acidophilic
SUSPENDED MACROMOLECULES
- include albumins, immunoglobulins, and other immune system proteins
- prothrombin, fibrinogen, and other clotting factors
- carrier molecules
- hormones
NEUTROPHILS
Polymorphonuclear Leucocytes
- spherical cells
- lobed nucleus (3-5)
- predominately heterochromatic (heterochromatin peripherally, euchromatin centrally)
- contains neutrophilic and azurophilic granules that are lightly stained
AZUROPHILIC GRANULES
- larger in size and fewer in number
- primary granules are modified lysosomes containing acid hydrolases and other enzymes including myeloperoxidase
- contains cationic proteins defensins
SPECIFIC GRANULES/NEUTROPHILIC GRANULES
- smaller in size and more numerous
- TEM barely visible at LM
- Secondary granules contain complement activators, bacteriostatic and bacteriocidal agents including type IV collagenase and phospholipase
TERTIARY GRANULES/TERTIARY SECRETORY GRANULES
- contain various enzymes
- one type has phospatases and the other has metalloproteinases
- short lived cells (10-12 hours)
- attracted by chemical factors, bacterial accumulations, tissue damage,and inflammation
- undergo autolysis
- can release contents of cytoplasmic granules extracellulary
HOW PHAGOCYTOSIS WORKS
- bacteria, dead cells, and other material sare ingested via phagocytosis or endocytosis/pinocytosis
- specific granules and then azurophilic granules fuse sequentially with phagosomes or endosomes to form secondary lysosomes
- Within secondary lysosomes, bateriostatic and bacteriocidal agents kill bacteria and acid hydrolases and other enzymes break down components of phagocytosed bacteria, cells and or other materials.
EOSINOPHILS
- spherical cells
- bilobed nucleus
- predominantely heterochromatic (peripherally), some euchromatic centrally
- cytoplasm has numerous large granules that exhibit acidophilic eosinophilic staining
- short lived (12-24 hours)
- exit via postcapillary venules into other tissues
- attracted by chemical factors to sites of allergic reactions, persistent parasitic infections, and tissue damage.
SPECIFIC GRANULES/ EOSINOPHILIC GRANULES
- large oval shaped granules
- contains a crystalloid body
- contains 4 major proteins: Major basic protein, eosinophil cationic protein, eosinophil- derived neurotoxin/EDN
- also contain histaminase, arylsulfatase, collagenase, and cathepsins
FUNCTION OF EOSINOPHIL
- endocytose materials broken down by acid hydrolases
- adher to large parasistic organisms and release contents of acidophilic granules extracellularly, major basic protein and other components destroy parasitic organisms, especially helminths
- release histaminase and arylsulfatase to inactivate specific vasoactive substances released by other blood cells or connective tissue cells
BASOPHILS
- spherical cells
- lobed nucleus (2-3)
- predominately heterochromatic with extensive peripheral heterochromatin and centrally located euchromatin
- cytoplasm contains one large granule and obscure the nucleus
- specific granules are the larger granules. They have heparin, heparan sulfate, histamine, and leukotrienes
- function in blood vascular tissue, but are able to function in extravascularlocations if needed.
- exhibits basophilic staining
BASOPHIL FUNCTION
- trigger vascular changes by exocytosing content of granules into extracellular spaces of blood
- the cell surface has receptors that bind to immunogloulin. The antigens bind to the cell surface and this triggers exocytosis of the specific granules and release of the vasoactive components into blood plasma.
HISTAMINE AND HEPARAN SULFATE
- causes vasodilation
- increases permeability of endothelium of postcapillary venules
LYMPHOCYTES
- spherical cells
- large spherical nucleus with indentation on one side
- predominately heterochromatic (peripheral) and euchromatic central
- basophilic cytoplasm
- thin rim of basophilic cytoplasm
- 3 types of lymphocytes: T cells, B cells, Natural killer cells
- T and B lymphocytes can be distinguished using SEM but not in LM
T LYMPHOCYTES/ T CELLS
- small cells with large nuclei
- thin rim of basophilic cytoplasm
- exits postcapillary venules
- migrate into and through other tissues
- long lived cells
- responsible for the cell mediated immune responses
FUNCTION OF T LYMPHOCYTES
- cytotoxic T cells kill or destroy virus infected cells and other foreign cells
- helper T cells function in cell-cell interactions
- suppress T cells downregulate immune responses
B LYMPHOCYTES/ B CELLS
- large nucleus
- basophilic cytoplasm
- responsible for antibody mediated immune responses
- differentiate into plasma cells that synthesize and secrete immunoglobulin/antibodies
NATURAL KILLER CELLS/LARGE GRANULAR LYMPHOCYTES
- eccentric nucleus
- large amount of basophilic cytoplasm
- kill virus infected cells and tumor cells
MONOCYTES
- spherical cells
- large eccentric nucleus
- indentation on side looks like bean shape.
- predominately heterochromatic (peripheral) and euchromatic (central)
- lightly basophilic stain
- small azurophilic granules
- migration from blood vascular tissue into various extravascular locations and subsequently differentiate into macrophages or related phagocytic cell types
GRANULOMERE/CHROMOMERE
- consists of organelle zone and membrane zone (TEM) in the platelets
- larger centrally located region
- stains more intensely basophilic with alpha granules for blood clotting, theta granules for ADp, ATP, serotonin, and histamine, and lamda granules that contain various hydrolases.
-contains membrane channels as calcium storage sites
HYALOMERE
- peripheral zone and structural zone of Platelets
- short lived
- stains less intensely basophilic
- contains plasmalemma, microtubules, and microfilaments
HOW TO REDUCE FLUID LOSS FROM DAMAGED BLOOD VESSELS
- platelets adhere to regions damaged endothelium
- ADP released from theta granule
- Serotonin released from theta granules causing vasoconstriction
- initiate events leading to formation of blood clot (release alpha granules causing enzymatic reactions and a blood clot.
PLEURIPOTENTIAL STEM CELL/HEMOCYTOBLAST
- as proliferation occurs new lineages develop.
- Myeloid pathway gives rise to erythrocytes, granulocytes, and monocytes
- lymphoid pathway gives rise to lymphocytes
- megakaryoblast - gives rise to megakaryocytes
- includes the liver, spleen, thymus, and bone marrow
POSTNATAL ORGANIZMS
- hemopoietic tissues are included in the thymus and bone.
- contains stem cells for all types of blood cells
- short lived
- stem cells are constantly proliferating to produce new cells that can undergo terminal cell differentiation
- during the early phases of cell division the nuclei of future blood cells is euchromatic and there are organelles but eventually it will be more heterochromatic and the cells will disappear.