Exam 1 Flashcards
(200 cards)
1
Q
What is histology?
A
A branch of anatomy that deals with the minute structure of animal + plant tissues as discernible with the microscope
2
Q
Fixation
A
Tissue samples placed in solutions of chemicals that will preserve the cell and tissue structure
3
Q
Dehydration
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Tissue is placed in a cassette, transferred through a series of concentrated alcohol to remove the water from the specimen
4
Q
Clearing
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An organic solution, that is miscible w/alcohol + paraffin, is used to remove the alcohol from the dehydrating step
5
Q
Infiltration
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Sample + cassette are placed in paraffin wax until it becomes infiltrated with the substance
6
Q
Embedding
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Sample is placed into a mold containing melted paraffin and cooled so it can harden
7
Q
Trimming
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Paraffin block is trimmed to expose the tissue for sectioning utilizing an instrument (microtome) to shave off thin sheets to be placed on a slide
8
Q
Mounting
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Slide is stained and the preserved by adding a glass coverslip
9
Q
Hematoxylin
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Basic dye that binds to acidic components. Has a positive charge. Stains negative structures blue
10
Q
Eosin
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Acidic dye, binds to basic components. Has a negative charge. Stains positive structures pink to red
11
Q
Collagen stains ____ color with the eosin dye
A
Pink
12
Q
Cell nuclei stain _______ with hematoxylin
A
Purple
13
Q
Giemsa-Wright Stain
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Stains red blood cells red. Stains white blood cells purple
14
Q
Silver stain
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Stains fungi + reticular fibers of the lymph nodes
15
Q
Periodic acid schiff (PAS) stains
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Stain carbohydrates, glycogen, and mucus deep red
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Q
Toluidine blue
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Stains mast cells purple and everything else blue
17
Q
Tissue composition
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Cells and extracellular matrix
18
Q
Organ composition
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Parenchyma and stroma
19
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Parenchyma
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Cells that perform the function of the organ
20
Q
Stroma
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Supporting tissue
21
Q
Functions of epithelium
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Covering of external surfaces, lining of internal surfaces, protection, absorption, secretion, sensation, and contraction
22
Q
Two kinds of epithelium
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Cover + lining epithelium and glandular epithelium
23
Q
Epithelium structure consists of?
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Basement membrane, connections between cells, and specialized apical structures
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Basement membrane
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Consists of the basal laminate and the reticular lamina
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Basal lamina
Connects directly to the epithelial tissues. Lamina lucida (loose) layer. Lamina densa (dense) layer
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What is the protein in the lamina lucida?
Laminin
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What is the protein in the lamina densa?
Type IV collagen + perlecan
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Reticular lamina
Connects the basal lamina to the underlying connective tissue
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What is the reticular lamina made up of?
Reticular fibers, anchoring fibrils, and anchoring plaques
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Functions of the basal lamina
Structure, organization, and filtration
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Intercellular junctions
Present in most tissues but more prominent in epithelial tissue
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What are the intercellular junctions?
Tight junctions, adherens junction, desmosomes, gap junctions, and hemidesosomes
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Tight junctions (zonula occludens)
Most apical junction. Forms bands that completely encircle each cell. Zonula occludens will fuse the membranes of adjacent cells to seal off the intercellular space.
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What are the proteins in tight junctions?
Claudins and occludins
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Belt desmosomes (zona adherens)
Forms a band that encircles each cell. A thick filament in the cytoplasm insert into attachment plaques
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What are the proteins in belt desmosomes?
Cadherin and catenin
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Spot desmosomes (macula adherens)
Spot adhesion between cells. Cytokeratin filaments insert into plaques in cell membrane. Provide strong attachment point between cells
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What is the protein in spot desmosomes?
Cadherins
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What are the proteins in the attachment plaques of the spot desmosomes?
Desmoplakin + plakoglobin
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Hemidesmosome
Uses integrins to attache to the epithelial cells to basal lamina
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Gap junctions (communicating junctions)
Occur anywhere along lateral surface of cells. Allows ions + other small molecules to pass through to facilitate cellular communication
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What is the protein in gap junctions?
Connexons
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Tight junction major functions
Seals adjacent cells to one another, controlling passage of molecules between them, separates apical and basolateral membrane domains
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Adherens junction major function
Provide points linking the cytoskeletons of adjacent cells, strengthens + stabilizes nearby tight junctions
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Desmosomes major functions
Provides points of strong intermediate filament coupling between adjacent cells, strengthening the tissue
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Hemidesmosome major functions
Anchors cytoskeleton to the basal lamina
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Gap junction major functions
Allows direct transfer of small molecules and ions from one cell to another
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Microvilli
Have a central core of actin filaments. Uniform in length and densely packed. Also called brush border
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What is the purpose of microvilli?
Increase the surface area for absorption or secretion
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Stereocilia
Long, non-motile projections that are similar to microvilli in structure. Found in parts of the male reproductive system + inner ear
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What is the function of stereocilia?
Assist with absorption
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Cilia
Long and wide projections. Perform a rapid beating pattern that moves fluid + suspended matter in one direction along epithelium
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Squamous cells
Flat. Width > height
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Cubodial cells
Square, round. Width = height
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Columnar cells
Tall and slender. Width < height
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Endothelium
A layer of simple squamous epithelia that lines the blood vessels, lymph vessels, the inner surface of the cornea, heart, lungs, nerves and muscles
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Mesothelium
Layer of simple squamous epithelia that lines large body cavities and secretes a lubricant film called serous fluid
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Simple squamous
Lining of vessels (endothelium), serous lining of cavities, pericardium, pleura, peritoneum (mesothelium)
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Simple squamous function
Facilitates the movement of visceral, active transport by pinocytosis, secretion of biologically active molecules
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Simple cubodial
Covering the ovary and thyroid
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Simple cuboidal function
Covering and secretion
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Simple columnar
Lining of the intestine + gallbladder
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Simple columnar function
Protection, lubrication, absorption, and secretion
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Stratified squamous keratinized
Epidermis
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Stratified squamous keratinized function
Protection and prevents water loss
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Stratified squamous nonkeratinized
Found in mouth, esophagus, larynx, vagina, and anal canal
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Stratified squamous nonkeratinized functions
Protection, secretion, and prevents water loss
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Stratified cuboidal
Sweat glands and developing ovarian follicles
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Stratified cuboidal functions
Protection and secretion
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Stratified transitional
Bladder, ureters, and renal calyces
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Stratified transitional functions
Protection and distensibility
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Stratified columnar
Makes up the conjuctiva
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Stratified columnar function
Protection
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Pseudostratified
Layers of cells with nuclei at different levels. Not all cells reach the apical surface but all cells adhere to basal surface
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Pseudostratified cells
Line the trachea, bronchi, and nasal cavity
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Pseudostratified cell function
Protection, secretion, cilia-mediated transport of particles trapped in mucus out of the air passages
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Unicellular glands
Found in simple columnar, simple cubodial, and Pseudostratified epithelia. Most commonly goblet cells
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Goblet cells
Secrete lubricating mucus and aids in the function of the organs they are found in
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Exocrine glands
Remain connected with the surface epithelium forming tubular ducts that lead to another organ/body surface, where secretion is used
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Endocrine glands
Lose the connection to their original epithelium and lack ducts
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Where are endocrine glands found?
Capillaries (thin walled blood vessels)
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Types of exocrine secretion
Merocrine, apocrine, and holocrine
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Merocrine
Secretion that releases products (usually containing proteins) by vessels at the apical end of the cell
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Apocrine
Secretion involves the loss of membrane-enclosed apical cytoplasm
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What is an example of apocrine glands?
Mammary glands
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Holocrine
Secretion is produced by the disintegration of the secretory cells themselves as they complete their terminal differentiation
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What is an example of holocrine glands?
Sebaceous glands of hair follicles
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Serous secretion
Excretes proteins that are mostly NOT glycosylated. Stain intensely with basophilic/acidophilic stains
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Examples of serous secretion
Acini of the pancreas and the parotid salivary gland
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Mucous secretion
Excretes heavily glyosylated proteins (mucins). Stain poorly with eosin/hematoxylin, but stains well with PAS
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Example of mucous secretion
Goblet cells
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Myoepithelial cells
Contractile cells at the basal end of secretory cells. Bonded to the basal lamina. Contains both actin and myosin filaments to perform contraction + propel secretory products from the duct into the duct system
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Metaplasia
The process of one type of epithelial tissue undergoing a transformation to another type of tissue. Reversible process
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Anaplasia
The formation of a cancerous growth. Lose all identifiable/specialized features
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Four types of tissue
Epithelium, connective tissue, muscle, and nerve
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What are tissues composed of?
Cells and extracellular matrix
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Functions of tissue
Support, packing, storage, transport, repair, and defense
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What is the extracellular matrix?
The major component of most types of connective tissue
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Types of specialized connective tissue
Adipose tissue, hematopoietic tissue, and lymphoid tissue
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Types of supporting connective tissue
Cartilage and bone
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Connective tissue proper
Surrounds delicate vessels, scaffolds lymph nodes, connects bones, and supports skin
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What does connective tissue develop from?
A precursor tissue called mesenchyme
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What is mesenchyme?
An undifferentiated tissue present only in early embryonic life. Gives rise to all connective tissue piles vessels and smooth muscles
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What makes up the extracellular matrix?
Protein fibers and ground substance
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What are the protein fibers in ECM?
Collagen fibers, elastic fibers, and reticular fibers
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What makes up the ground substance in ECM?
Glycosaminoglycans, proteoglycans, and glycoproteins
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Collagen fibers
Flexible, non-extensible. Made of polypeptide chains
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Elastic fibers
Stretchy. Made of elastic and fibrillin
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Reticular fibers
Fine, delicate fibers found in *most notably* immune organs
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Type 1 collagen function
Resistance to tension
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Type 1 collagen locations
Skin, bones, tendons, and organ capsules
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Type II collagen function
Resistance to pressure
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Type II collagen location
Cartilage
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Type III collagen function
Delicate, flexible structural support
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Type III collagen location
Lymph nodes, spleen, bone marrow, basement membrane
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Collagen synthesis
Tropocollagen is synthesized by fibroblasts + released into extracellular space where it is polymerized to form collagen fibrils
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Chondroblasts
Build collagen
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Osteoblasts
Build bones
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Odontoblasts
Builds teeth
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Structure of elastic fibers
Composed of an elastin core (amorphous) surrounded by microfibrils (composed of fibrillin)
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Where are elastic fibers found?
Ligamentum flava, ligamentum nuchae, and large arteries
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Glycosaminoglycans (GAGs)
Chains of disaccharides
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Hyaluronic acid
Type of GAG that does NOT need a core protein
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All other GAGs
Short and ALWAYS bound to a core protein
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Proteoglycans
Consist of a protein core with a bunch of attached GAGs. Contain more carbohydrate than protein
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Glycoproteins
Globular proteins with attached carbohydrates. Contain more protein than carbohydrates
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Fibronectin
Present throughout connective tissue. Mediates normal cell adhesions and migration
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Laminin
Present in basal lamina. Helps epithelial cells stick to basal lamina. Important in cell differentiation and migration
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Types of fixed (intrinsic) cells
Fibroblasts + fibrocytes, mesenchymal cells, adipocyte, and fixed macrophages
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Fixed cells function
Production and maintenance of ECM
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Free (extrinsic) cells
Free macrophages, mast cells, plasma cells, and leukocytes
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Free cells function
Tissue reaction to injury or invasion of microorganisms
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Fibroblasts
Spindle-shaped. Most common in connective tissue. Make collagen, elastin, and ground substance
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Adipocytes
Store lipid. Incapable of division. Appears as a large empty space
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Mesenchymal cells
Undifferentiated cells. Stellate shape. Near blood vessels
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Fixed macrophages
Irregular shape with dark indented eccentric nucleus. Strongly acidophilic. Derived from monocytes. Actively mobile + leave the blood stream to enter connective tissues. Involved in phagocytosis
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Plasma cells
Oval basophilic cells with eccentric nucleus that has a “cartwheel” appearance. Derived from B lymphocytes. Present in respiratory + GI tracts
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Mast cells
Found near blood vessels in skin + mucosal linings. Vesicles with granules that contain histamine, heparin, and other chemicals that cause vasodilation + anticoagulant properties
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Granulocytes
Neutrophils, eosinophils, and basophils
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Agranulocytes
Lymphocytes and monocytes
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4 types of connective tissue proper
Loose areolar, loose reticular, dense regular, and dense irregular
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Dense regular function
Resists stretching forces in ONE direction
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Dense regular location
Tendons and ligaments
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Dense irregular function
Resists stretching forces in multiple directions
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Dense irregular location
Dermis and organ capsules
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Loose areolar function
Provides delicate support and cushioning
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Loose areolar location
Under epithelium and around blood vessels
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Loose reticular function
Provides a flexible structural framework
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Loose reticular locations
Lymph nodes, spleen, and bone marrow
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Dense regular appearance
Thick, pink collagen bundles all parallel to each other
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Dense irregular appearnace
Thick, pink collagen bundles running in different directions
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Loose areolar appearance
Lots of ground substance with scattered cells and thin fibers
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Loose reticular appearance
Delicate network of fine type III collagen (reticular) fibers
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Metabolic activity of bone? Blood supply of bone? Does bone heal?
Highly active; good blood supply; yes
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Metabolic activity of cartilage? Blood supply of cartilage? Does cartilage heal?
No activity; no blood supply; does not heal
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Chondroblasts
Cells that will differentiate into chondrocytes
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Chondrocytes
Mature cartilage cells that lie in lacunae
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What is collagen extracellular matrix composed of?
Collagen fibers, elastic fibers, GAGs, and proteoglycans
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Perichondrium
Covers the surface of the hyaline + elastic cartilage. Layer of dense connective tissue with fibroblast and type I collagen. No blood vessels
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Hyaline cartilage is made of ______
Type II collagen fibers
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Elastic cartilage is made of ______
Type II collagen fibers + elastic fibers
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Fibrocartilage is made of ________
Type I collagen fibers
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Hyaline cartilage function
Supports soft tissue, lines joints, and growth of bones
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Hyaline cartilage location
Lines articular surfaces if the joints, large respiratory passages, and epiphyseal plates
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What type of cartilage is the most abundant?
Hyaline cartilage
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Chondromas
Benign tumors from cartilage cells
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Chondrosacrcomas
Malignant tumors from cartilage cells
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Elastic cartilage location
Pliable and flexible ares. Pina of the ear, external auditory canal, auditory (eustachian) tube, epiglottis, and larynx
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Fibrocartilage location
Areas subject to pulling forces. Intervertebral discs, pubic symphysis, + attachment for tendons and ligaments
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Fibrocartilage function
Provides cushioning, tensile strength, and resistance to tearing and compression
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Elastic cartilage function
Provides flexible shape and support of soft tissues
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Interstitial cartilage growth
Growth within the cartilage. Chondrocytes divide and secrete matrix
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Appositional cartilage growth
Growth along the outside of the cartilage. Chrondroblasts secrete matrix and differentiate into chondrocytes
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Epiphyseal (growth) plate
A layer of hyaline cartilage that lets the diaphysis of the bone to grow in length
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Epiphyseal line
When bone stops growing in length the hyaline cartilage of the epiphyseal plate is replaced by bone
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Compact (lamellar) bone
Tightly compacted osseous material
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Spongy (trabecular) bone
Looks like a sponge or lattice
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Cells within the bone
Osteoblasts, osteocytes, and osteaclasts
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Osteoblasts
Produce organic part of bone matrix. Make bone
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Osteocytes
Maintenance of bone matrix. Their death results in reabsorption of bone matrix
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What promotes bone formation?
Testosterone, estrogen, growth hormone, weight-bearing exercise, and muscle use
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Osteoclasts
Reabsorb osteoclasts adjacent to bone. Have multiple nuclei. Act as lysosomes
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Immature (primary or woven) bone
First bone laid down during development. Formed quickly. Unorganized
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Mature (secondary or lamellar) bone
Arranged into ostensibly. Organized
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What are the parts of the Haversian system?
Osteons, lacunae + canals, lamellae, and canals in the bone
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Osteons
Components of compact bone tissue arranged in concentric structural units. Form in the same direction as the stress lines
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What do Osteons provide?
Protection, support, and stress of body weight
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Lacunae and canals
The bone matrix is calcified trapping osteocytes in lacunae. Osteocytes maintain the calcified matrix and receive nutrients from central canals + canaliculi
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Concentric lamellae
Rings of calcified extracellular matrix around the Haversian canals
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Interstitial lamellae
The areas between osteons
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Volkamnn’s (perforating) canals
Horizontal canals for blood vessels, lymphatics, and nerves. Connects the periosteum to the medullary cavity
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Haversian (central) canals
Vertical canals for blood vessels, lymphatics, and nerves
193
Piezoelectric effect
The property of some materials to convert mechanical energy to electrical current
194
Periosteum
Lines the outer surface of compact bone. Contains an outer layer of dense connective tissue. Internal layer includes osteoblasts + mesenchymal cells
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Endosteum
Covers the internal surface of the cell including the small trabeculae + haversian canals
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Osteogenesis
Bone development
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Intramembranous ossification
Osteoblasts differentiate directly from mesenchyme and begin secreting osteoid
198
Intramembranous ossification process
1. Mesenchyme condenses
2. Ossification centers form
3. Mesenchyme becomes osteoblasts
4. Osteoids are produced
5. Osteoids are calcified
6. Neighboring ossification centers merge together to form woven bone
7. Periosteum starts to form
8. Lamellar, compact bone + spongy bone layers form
199
Endochondral ossification
Preexisting matrix of hyaline cartilage is eroded + invaded by osteoblasts, which then begin osteoid production
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Endochondral ossification process
1. Cartilage model is formed in-utero
2. Bone collar forms which suffocate cartilage cells
3. Blood cells bring in osteoprogenitor cells
4. Primary ossification centers form from osteoprogenitor in diaphysis
5. Lamellar bone forms in shaft
6. Secondary ossification centers develop at birth in epiphysis of bones
7. Epiphyseal plates stay open /grow until a person is fully grown
