Flashcards in Histology Objectives Deck (42)
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Histology
study of tissues
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Extracellular Matrix
material outside of and between cells. in many tissues it includes various types of proteinaceous fibers (extracellular fibers) as well as amorphous protein/polysaccharide material called ground substance.
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Ground Substance
the protein/polysaccharide component "glue" of the extracellular matrix.
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Extracellular Fibers
component of the extracellular matrix (usually made of protein)
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Epithelial Tissue
(Compare the 4 basic tissues in regard to regenerative capacity, major subtypes, germ layer, type and quantity of intercellular material, and major functions)
1. Type/Quantity of Intercellular Material: essentially none
2. Regenerative Capacity: high
3. Major Types: membranous and glandular epithelium
4. Origin: endoderm, mesoderm, and ectoderm
5. Function: secrets and covers surfaces
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Muscle Tissue
(Compare the 4 basic tissues in regard to regenerative capacity, major subtypes, germ layer, type and quantity of intercellular material, and major functions)
1. Type/Quantity of Intercellular Material: a small amount of c.t. proper
2. Regenerative Capacity: low
3. Major Types: smooth, cardiac, and skeletal muscle tissue
4. Origin: mesoderm
5. Function: contracts (can create electrical impulses)
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Connective Tissue
(Compare the 4 basic tissues in regard to regenerative capacity, major subtypes, germ layer, type and quantity of intercellular material, and major functions)
1. Type/Quantity of Intercellular Material: abundant fibers and ground substance
2. Regenerative capacity: high
3. Major Types: c.t. proper, bone, blood, cartilage, adipose tissue, and Reticular connective tissue, Bone Marrow tissue, Primitive connective tissue
4. Origin: mesoderm
5. Function: joins (connects) other structures
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Nervous Tissue
(Compare the 4 basic tissues in regard to regenerative capacity, major subtypes, germ layer, type and quantity of intercellular material, and major functions)
1. Type/Quantity of Intercellular Matrix: essentially none
2. Regenerative Capacity: low
3. Major Types: not subdivided into types, but has two major cell types
4. Origin: ectoderm
5. Function: conducts impulses
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Gives the names of all 4 ways you can name a muscle cell
muscle cells, myofibers, muscle fibers, myocytes
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Skeletal Muscle Tissue
(differentiate the 3 types of muscle tissue in regard to: voluntary/involuntary, presence/absence of striations, cell shape, number and position of nuclei, and location in body)
1. under direct voluntary control of nervous system
2. alternating stacks of myofilaments in the myofibrils causes a differential cross-hatched or striated appearance
3. large cylindrically-shaped cells
4. several nuclei located near the peripheral aspects of the cytoplasm
5. located in the skeletal muscles
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Cardiac Muscle Tissue
(differentiate the 3 types of muscle tissue in regard to: voluntary/involuntary, presence/absence of striations, cell shape, number and position of nuclei, and location in body)
1. has inherent rhythmicity and thus is involuntary
2. striated
3. branched ( Y shaped) cells
4. centrally located nucleus
5. located in the contractile parts of the heart
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Smooth Muscle Tissue
(differentiate the 3 types of muscle tissue in regard to: voluntary/involuntary, presence/absence of striations, cell shape, number and position of nuclei, and location in body)
1. it is involuntary, has inherent rhythmicity and is under the influence of the autonomic nervous system
2. there are no striations
3. fusiform shaped
4. single, centrally located nuclei
5. located within the blood vessels, in the walls of visceral organs, at the base of hair follicles, and within the iris and ciliary body of the eye
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Membranous Epithelium
(differentiate on the basis of blood supply, presence of basement membrane, and general location in body)
1. avascular, aneural, and varies in thickness from one cell to several dozen cells thick
2. cells are separated by a basement membrane
3. covers the outer surfaces and the inner surfaces of the body
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Glandular Epithelium
(differentiate on the basis of blood supply, presence of basement membrane, and general location in body)
1. highly vascularized, innervated
2. lacks a basement membrane
3. located in glands
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Classify membranous epithelium into 6 categories on the basis of its thickness (one cell/more than one cell) and the shape of the surface cells (squamous, cuboidal, columnar)
One cell thick
1. simple squamous epithelium
2. simple cuboidal epithelium
3. simple columnar epithelium
More than one cell thick
4. stratified squamous epithelium
5. stratified cuboidal epithelium
6. stratified columnar epithelium
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Name and state the location of two types of membranous epithelium that do not fit the usual classification scheme. Indicate what is meant by "respiratory" epithelium.
1. Pseudostratified columnar epithelium: appears to be more than one cell thick because some cells are short and do not reach the surface (THEY ARE IN CONTACT WITH THE BASEMENT MEMBRANE SO ONLY ONE CELL LAYER THICK)
- located in the air conducting passageways of the respiratory system and is sometimes called "respiratory epithelium"
2. Transitional Epithelium: lines the urinary bladder, ureters, and part of the urethra
- appears to be composed of several layers of cuboidal cells but IN CONTACT WITH THE BASEMENT MEMBRANE SO ONLY ONE CELL THICK)
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Discuss the kinds and functions of modifications found in the surface cells of membranous epithelium.
1. Cilia- relatively long projections that the cells use to propel materials along the surface
2. Microvilli- specialized for absorption by increasing the surface area
3. Keratin- dense protein manufactured by the stratified squamous epithelium of the skin; it remains within the cells but imparts physical strength and resistance to desiccation (drying)
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Endocrine/Exocrine
(Define the following terms used to classify glandular epithelium)
Endocrine Glands: glands that lose all connections to the surface and secrete their products directly into the bloodstream; their secretory products are called hormones
Exocrine Glands: glands that maintain a surface or lumen connection by being physically located at the surface (goblet cells) or by having a duct that reaches a body surface (or lumen)
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Simple/Compound
(Define the following terms used to classify glandular epithelium)
Simple: non-branching of ducts
Compound: branching of ducts
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Eccrine (merocrine)
watery secretion, no structural parts of the secretory cells become part of the secretion
ex) some sweat glands, salivary glands, liver, pancreas
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Apocrine
parts of secretory cells are lost into (become part of) the secretion
ex) mammary glands and some sweat glands (stinky sweat)
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Holocrine
entire cells of the gland are lost into (become part of) the secretion
ex) sebaceous glands of skin, ceruminous glands of external acoustic meatus (wax and oil)
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Acinar
shape of their secretory units is spherical
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Tubular
shape of their secretory units is tubular
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Tubuloacinar
shape of their secretory units is both tubular and acinar
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Differentiate the development of endocrine vs. exocrine glands.
All glandular epithelium develops from membranous (surface) epithelium. Membranous epithelium that becomes glandular may remain on the surface, maintain a surface contact in the form of a duct, or may lose a surface contact all together. If it maintains surface contact = exocrine glands. If it loses surface contact = endocrine glands
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List 3 components found in all connective tissues.
Fibroblasts secrete three kinds of extracellular products and well as the ground substance of the matrix:
1. Collagenous fibers (composed of protein called collagen)
2. Elastic fibers (composed of protein called elastin)
3. Reticular fibers (composed of protein called reticulin)
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Classify c.t. proper on the basis of density, arrangement, and fiber composition.
1. Fiber Density (loose/dense) - tightly packed vs. considerable space around them
2. Fiber Arrangement (regular/irregular) - oriented in a relatively parallel manner or not parallel to each other
3. Fiber type present (collagenous fiber, elastic fibers, and reticular fibers) - if they don't have anything listed at all it's assumed they have all 3
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Name the subtypes of cartilage and state the predominant fiber type present in each
Fibrocartilage: dense collagenous fibers in the matrix impart strength and resistance to tearing and compression
-forms outer parts of intervertebral discs (between vertebrae)
Elastic cartilage: has significant numbers of elastic fibers in the matrix which impart flexibility
-found in the external ear and parts of larynx
Hyaline cartilage: has delicate collagenous ("reticular") fibers within its matrix
-found on the articular surfaces of bones (think of fried chicken and the shiny part on the joint, made so your bones don't rub together)
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