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376 Cards in this Set
- Front
- Back
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define epithelium
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epithelium consists of sheets of aggregated cells of similar type that cover or line the external or internal surfaces of the body
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what does epithelium rest on ?
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basement membrane
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what can basement membrane be stained with?
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PAS technique or silver salt
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what does the basement membrane consist of?
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Lamida lucida
lamida densa subbasal lamina |
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what is the lamida lucida?
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clear, low density, next to epithelium
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what is the lamida densa?
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electron dense, these two laminae are synthesized by the and are composed of mainly proteoglycans and a special kind of collagen.
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what is subbasal lamina?
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reticular fibers. Connects the lamina densa to the subepithelial CT.
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what is the function of the basement membrane?
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protection, absorption, secretion, and diffusion.
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what is classification of epithelium based on?
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number of layers and shape of cells
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define simple epithelium
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single layer of cells resting on the basement membrane
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define stratified epithelium
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two or more layers of cells with only the basal cell layer resting on the basement membrane
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what are the three shapes of cells
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squamous, cuboidal, and columnar
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what do squamous cells look like?
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thin, flat, scale-like. Sperical or oval nucleus- gives slightly elevated buldging appearance.
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where is simple squamous epithelium found?
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blood vessels, pleural and peritoneal cavities, pulmonary alveoli, and glomerular capsule.
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what do cuboidal cells look like?
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cube shaped with a centrally placed nucleus
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where is simple cuboidal epithelium found?
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thyroid gland, collecting ducts of the kidney
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what do columnar cells look like?
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tall, narrow. Nucleus is oval and located near the base of the cell.
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where are simple cuboidal cells found?
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stomach, small intestine, and gall bladder.
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describe pseudostratified columnar epithelium.
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composed of a single layer of cells, but because of the different cell shape and nuclei location at different levels, it gives the impression that there is more than one layer.
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where is pseudostatified columnar epithelium found?
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trachea and bronchi (ciliated form)
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where is stratified squamous epithelium found?
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skin (keratinized form) and cornea (non-keratinized)
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where is stratified cuboidal epithelium found?
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lining of the excretory ducts of glands
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where are stratified columnar cells found?
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in parotid and mandibular gland ducts
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where is transitional epithelium found?
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lines certain hollow organs capable of distension. eg urinary bladder and urethra
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glands consists of what three things?
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1.glandular or secretory epithelium
2. duct system (parenchyma) 3. supportive framework (stroma) |
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define endocrine
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ductless gland, their secretions are released into intercellular fluid and transported to the site of action via blood
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define exocrine
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a system with ducts can either be simple or compound
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what are the 6 types of simple glands?
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simple straight tubular
simple coiled tubular simple branched tubular simple alveolar or acinar gland simple branched acinar or alveolar simple tubulo-acinar gland |
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what are the 3 types of compound glands?
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compound tubular
compound alveolar compound tubulo-alveolar |
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where are simple straight tubular glands found?
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large intestine
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where are simple coiled tubular glands found?
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sweat glands
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where are simple branched tubular glands found?
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stomach
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where are simple alveolar or acinar glands found?
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sebaceous gland
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where are simple branched acinar glands found?
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large sebaceous gland
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where are simple tubulo-acinar glands found ?
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minor salivary gland of oral cavity
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where are compound alveolar glands found?
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parotid gland
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where are compound tubulo-alveolar glands found?
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pancreas
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what type of secretion do serous glands produce?
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thin watery secretions
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what type of nuclei do serous glands have?
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spherical either in the center or in the lower half of their apical cytoplasm
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what does apical mean?
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pertaining to the apex
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what is contained in the apical cytoplasm of serous glands?
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zygomen granules: small secretory granules
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where are serous glands found?
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parotid salivary gland
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what type of secretion do mucus glands produce?
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thick viscous mucin
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what is the function of the mucus gland secretion?
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protective covering
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what type of nuclei do mucus glands have?
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flattened displaced toward the basal part of the cell
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what does basal mean?
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situated toward the base, in physiology, pertaining to the lowest possible level.
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which glands (mucus or serous) stain lightly?
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mucus, they stain lighty with H&E because of mucin
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what does acini mean?
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the smallest lobule of a compound gland
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what gland contains both serous and mucous acini?
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seromucous or mixed
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in seromucus glands, how are the cells arranged?
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serous glands are located over the mucous acini as serous demilunes
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where are seromucus glands found in the body?
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mandibular salivary gland
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how is the secretory product of merocrine cells released?
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secretory granules are discharged by exocytosis
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what is the most common mode release of secretory products of glands?
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merocrine.
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what is the mode of release of secretory products of apocrine glands?
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membrane bound granule together with a rim of cytoplasm and plasmalemma is released from the apex of the cell.
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what are two examples of aporcrine glands?
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sweat and mammary glands
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what is the mode of release of secretory products of halocrine glands?
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entire cell is released as the secretory product
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where are halocrine glands found?
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sebaceous glands
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what is the mode of release of secretory products of cytocrine cells?
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the secretory material from one cell is transferred to the cytoplasm of another cell.
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what is an example of cytocrine secretion?
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transfer of melanin pigment from teh melanocytes into the ketatinocytes
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where are myoepithelial cells located?
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between secretory cells and basement membrane
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when contracted what do the myoepithelial cells do?
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force the secretory product into the duct system
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connective tissue is composed of what three things?
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cells, fibers, and amorphous ground substance.
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what are the 10 types of cells found in CT?
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mesenchymal, fibroblasts, reticular, adipocytes, pericytes, mast, plasma, macrophage, pigment, and leukocytes
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what are the three types of fibers found in CT?
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collagen, elastic, and reticular
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what is found in amophous ground substance?
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proteoglycans, glycosaminoglycans, and interstitial fluid
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what do mesenchymal cells look like?
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irregularly shaped, multiple processes
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where are mesenchymal cells located?
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around blood vessels
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what is the function of mesenchymal cells?
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they are pluripotent
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what is the function of fibroblast cells?
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synthesis of fibers and intercellular ground substance
Wound repair. |
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what is the difference between fibroblast and myofibroblast?
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myofibroblast contains actin
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what is the function of myofibroblast?
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wound repair with contraction
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what do reticular cells look like, what do their nuclei look like?
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stellate (star) shaped
sperical nucleus basophillic (blue) cytoplasm |
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what is the function of reticular cells?
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to produce reticular fibers
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what do uniocular adipocyte cells look like?
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one fat drop with a peripheral nuclei
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what is the function of uniocular adipocytes?
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not active
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what do multiocular adipocytes look like?
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many fat drops, central nucleus
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what is the function of mutiocular adipocytes?
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very active, increase mitochondria concentration
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what is the shape of pericytes?
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elongated
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what do pericytes contain?
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actin and myosin
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what is the function of pericytes ?
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pluripotent, healing process
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where are pericytes located?
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endothelium of small blood vessels
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what do mast cells look like ?
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large, spherical, or ovoid
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what is unique about mast cells, in terms of staining?
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they are metachromatic. Stain with toluidine blue, they stain RED
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what do mast cells contain?
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numerous secretory granules in the cytoplasm
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what do mast cells produce?
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heparin and histamine
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where are mast cells found?
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in loose CT around blood vessels
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what do plasma cells look like, what about their nuclei?
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sperical or ovoid, eccentric cart-wheel like nucleus
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what does eccentric mean?
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located elsewhere than the center
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how does the cytoplasm stain in plasma cells?
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basophillic (blue)
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what is the function of plasma cells, what do they produce?
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B-lymphocytes/ Antibodies
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where are plasma cells located?
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lymphatic tissue and lamina propria of GIT
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what do macrophages look like?
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large ovoid or sperical
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what do macrophages contain?
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cytoplasmic vacuoles and numerous lysosomes
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what is the function of macrophages?
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phagocytosis
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where are macrophages located?
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migrate across blood vessel walls to CT
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where are pigment cells found?
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uterine carnucles, dermis, choroid iris
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what are three examples of leucocytes?
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lympocytes
monocytes granulocytes |
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where are leucocytes found?
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migrate through the walls of capillaries to CT
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where are collagen fibers found?
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tendon, ligament, and organ capsule
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where are collagen fibers most abundant?
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in mature CT
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what are collagen fibers composed of?
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the fibrous protein: collagen
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what is collagen like physically?
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strong, flexible, but inelastic
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what kind of arrangement do collagen fibers have?
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wavy
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fresh collagen fibers are what color?
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white
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what are collagen fibers stained red with?
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Van Gieson's Method
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what are collagen fibers stained red with?
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Masson's Trichrome stain
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reticular fibers form what kind of networks?
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delicate, flexible networks
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where are reticular networks found?
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around capillaries, muscle fibers, and nerves
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reticular fibers form the framework for?
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liver, endocrine, and lymphatic organs
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what can reticular fibers be stained with?
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silver impregnation or PAS reagent
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what are reticular fibers actually?
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individual collagen fibrils (type III) coated with proteoglycans and glycoproteins
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where are elastic fibers located?
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aorta, muscular arteries, nuchal ligament, pinna of ear, and lungs.
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how do elastic fibers usually occur?
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as individual, branching or coiled fibers
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when stained with H&E what color do elastic fibers present themselves as?
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light pink
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what else can elastic fibers be stained with?
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orcein and resorcin-fuchsin
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what are elastic fibers composed of?
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elastin protein, covered by glycoprotein (fibrillin)
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where is hyaluronic acid found?
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vitreous body of eye and in synovial fluid
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where is chondroitin sulphate found?
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in cartilage, bone, and large blood vessels.
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where is dermatin sulphate found?
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in tendons and ligaments
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where is keratin sulphate found ?
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in cartilage and bones
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where is heparin sulphate found?
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in arteries and lungs
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what are the 5 major types of Glycosaminogylcans?
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Hyaluronic acid
chondroitin sulphate dermatin sulphate keratin sulphate heparin sulfate |
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how are proteoglycans formed?
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by covalently linking GAG's to a protein core. .
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what are the two types of embryonic connective tissue
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mesenchymal and mucous or gelatinous CT
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what is mesenchymal CT composed of?
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mesenchymal cells and amorphous fluid-filled ground substance
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where is mucous or gelatinous CT found?
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in umbilical cord in the embryo and papilllae of omasal laminae and retiular fold and bovine glans penis.
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what is mucous or gelatinous CT composed of?
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stellate fibroblasts and viscous, gel like amorphous ground substance with collagen fibers
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What are the 5 types of adult CT?
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1. Loose or areolar
2. dense 3. elastic 4. reticular 5. adipose |
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where is loose or areolar CT found?
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beneath the epithelium (lamina propria, hypodermia), around blood vessels and nerves and in serous membranes
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what predominates in loose or areolar CT?
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ground substance
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what does loose or areolar CT consist of?
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fine collagenous, reticular, and elastic fibers
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what is dense CT consist of?
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thick collagenous fibers and few fibroblast cells
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where is dense irregular CT found?
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capsules of the organs, deep layer of dermis
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dense regular CT is found where?
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tendons, ligaments, and aponerosis
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Elastic tissue is characterized how?
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by numerous regularly or irregularly arranged elastic fibers.
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where is elastic tissue found?
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nuchal ligament and vocal ligament
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what is reticular tissue composed of?
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numerous reticular cells and a network of reticular fibers
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where is reticular tissue found?
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spleen, lymph node and liver
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adipose tissue is composed of?
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adipocytes with loose CT of mesenteries
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where is adipose tissue located?
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around blood vessels and nerves
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what are the two types of adipose tissue?
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white and brown
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What does cartilage consist of?
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cartilage cells (chondroblasts and chondrocytes) and matrix. LACKS BLOOD VESSELS
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what is the shape of the chondroblast cell and nucleus?
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cell is oval shaped with a sperical nucleus and basophillic cytoplasm
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what do the chondroblast cells form?
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the matri of the cartilage and are found in the growing cartilage.
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where are chondrocytes located?
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in a lacuna
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what is the shape of the chondrocyte nucleus? how does its cytoplasm stain?
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spherical nucleus
basophillic cytoplasm |
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what is the cartilage matrix composed of?
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fibers and ground substance containing proteoglycans and GAGs and the adhesive molecules (chondronectin and fibronectin)
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what does the cartilage matrix show?
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marked metachromasia
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where is hyaline cartilage found?
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articular sufaces of the bones, nose, and trachea
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how do chondrocytes occur in hyaline cartilage?
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singly in a lacuna or in clusters called an isogenous group
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what type of fibers doe the ground substance of hyaline cartilage contain?
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type II collagen fibers, which have the same refractive index as ground substance
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the ground substance of hyaline cartilage is divided into dark and light territory, why?
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dark territory= high concentration of sulphated GAGs and pale stained interterritorial matrix.
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what is hyaline cartilage surrounded by?
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perichondrium
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what is the outer fibrous layer of the perichondrium composed of?
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collagen fibers and fibroblasts and in inner cellular or chondrogenic layer (chondroblast)
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where is elastic cartilage found?
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pinna and epiglottis
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elastic cartilage is similar to hyaline cartilage with the exception that elastic contains?
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a large amount of elastic fibers which are embedded in the ground substance
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where is fibrocartilage found?
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intervertebral discs and menisci
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what is fibrocartilage characterized by?
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presence of prominent type I collagen fibers in the matrix
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fibrocartilage resembles dense irregular tissue with the exception of?
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fibrocartilage contains chondrocytes
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what is the major thing that fibrocartilage is lacking?
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perichondrium, however, it is surrounded by collagen fibers
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what is bone tissue composed of?
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intercellular calcified material (bone matrix) and three cell types (osteoblasts, osteocytes, and osteoclasts)
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what do osteoblast cells look like? where are they located?
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varies from columnar to squamous in shape and are located on the surface of bone.
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where is the osteoblast nucleus located, what does its cytoplasm look like?
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located at the basal region of the intensly basophillic cytoplasm
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what do osteoblasts secrete?
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osteoid (organic matter of bony matrix) which is later calcified by the depostion of calcium salts
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what are osteocytes derived from?
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osteoblasts
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where are osteocytes located, what are they surrounded by?
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lies in lacuna, surrounded by calcified interstitial matrix
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how do osteocytes make contact with one another?
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their long processes extend into the canaliculi within the matrix and make contact with each other
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what is the osteoclast nucleus like?
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large and multinucleated
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where is the osteoclast cell located?
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in the area of bone reporption or remodeling
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what does the osteoclast cell look like?
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has a ruffled border created by extensive infolding of the cell membrane
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what do osteoclasts secrete?
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acid and lysosomal enzymes for bone resorption
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what does bone matrix consist of ?
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organic and inorganic matter
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what does organic matter of bone matrix consist of?
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sulphated GAGs, glycoprotein, and type I collagen fibers coursing in spiral direction
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what does inorganic matter of bone matrix consist of?
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calcium and phosphorous- mainly but, bicaronate, citrate, magnesium, potassium, and sodium are also found
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what do the calcium and phophorous form in bone matrix?
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hydroxyapatitie crystals deposited as slender needles within the collagen network
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what are the three parts of the bone?
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epiphysis, diaphysis, and epiphyseal cartilage
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periosteum consists of what two layers?
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fibrous and osteogenic layers
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where is periosteum absent?
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on articulating surfaces, and at sites where tendons and ligaments insert on bone
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Sharpeys fibers connect what to what?
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collagen fibers from the fibrous layer of the periosteum, tendons and ligaments are embedded in the bone matrix as perforating (Sharpey's) fibers
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where is endosteum located?
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lines the marrow cavity
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what does endosteum consist of?
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a single layer of squamous cells, osteoblasts and osteocytes
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where is compact bone and spongy bone located?
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compact- forms the outer shell of the diaphysis and epiphyses, whereas spongy bone occurs in the interior of the epiphyses
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what does spongy bone consist of?
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delicate bony plates and spicules which run in various directions
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compact bone consists of what?
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osteons or haversian systems, outer and inner cirumferential lamellae and interstitial lamellae
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each osteon consists of what?
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a central canal surrounded by concentric lamellae
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the central canal consists of what?
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blood vessels, nerves, loose CT
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what do concentric lamellae consist of?
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collagen fibers arranged concentrically around the central canal
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lacunae are found where?
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lacunae containing osteocytes are found between the lamellae
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each osten is surrounded by?
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a cementing substance that consists of mineralized matrix with a few collagen fibers.
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the central canals are connected by?
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perforating canals
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intramembraneous ossification occurs where?
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skull except for the base of the skull
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intracartilagenous or endochondral ossification occurs where?
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appendicular skeleton, vertebral colomn, and bones of the base of the skull.
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muscle cells have what property?
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contractibility and produces organized movement on contraction.
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what are the muscle cells called?
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myocytes (muscle fibers or myofibers)
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what is the cytoplasm called in muscles?
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sacroplasm (stains red)
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how does the sacroplasm stain?
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eosinophillic because of numerous myofilaments
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what are the 3 types of muscles?
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skeletal
cardiac smooth |
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what does skeletal muscles look like?
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striated, elongated cells that range from 10-110 um in dimater and 50 cm in length
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what type of nuclei do skeletal muscles have?
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multiple oval nuclei located peripherally
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where are skeletal muscles found?
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attached to the bones of the skeleton
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each skeletal muscle contains what?
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myofibrils aligned in longitudinal direction
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myofibrils are composed of?
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thick and thin filaments
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thick filaments consist primarily of?
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myosin
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thin filaments are composed of?
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actin, troponin, and tropomyosin
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where are skeletal myofibrils derived from?
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prenatal fusion of many mononuclear myoblasts.
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thick and thin filaments overlap where?
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in the darker A band (anisotrophic)
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thin myofilaments only are located where?
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lighter I band (isotrophic)
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what is responsible for striation?
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alternating light and dark bands
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each I band is bissected by a dark transverse line, being the?
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Z line
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The A band shows a lighter zone in the center, the ___ band, which is besected by the ____ line.
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H band
M line |
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the smallest unit of contractile apparatus in skeletal muscle is the ?
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sacromere, in between two adjacent z lines
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the sacroplasm contains what 4 things?
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smooth ER
glycogen mitochodria myoglobin |
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what is the sacroplasm covered by?
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sacrolemma (cell membrane)
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each muscle fiber is surrounded by?
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endomysium (basal lamina and reticular fibers)
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A fascile is?
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a bundle of muscle fibers
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a fascile is surrounded by?
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perimysium (dense irregular CT)
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the muscle at the gross anatomical level is surrounded by ?
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epimysium (dense irregular CT)
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what is the shape of satellite cells, what do their nuclei look like, and where are they located?
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spindle-shaped
heterochromatin nuclei located adjacent to myocytes |
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what do satellite cells represent?
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inactive myoBLASTS
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what is the function of the inactive myoblasts which are represented by satellite cells?
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they can be activated upon injury to initiate some regeneration of muscle fibers.
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red muscle fibers are?
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slow twitch
smaller rich in myoglobin and mitochondria |
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white muscle fibers are?
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fast twitch
larger few mitochondria |
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what do cardiac muscles look like?
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striated
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are skeletal muscles voluntary?
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yes
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are cardiac muscles voluntary?
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no
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are smooth muscles voluntary?
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no
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what do cardiac myocytes do?
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branch and anastomose
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what does cardiac muscle nuclei look like?
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single nucleus is located at the center of the cell
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what does the sacroplasm of cardiac muscle look like?
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acidophillic (red)
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what are present at junctions of adjacent cells in cardiac muscle and are linked mechanically and electrically?
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intercalated disc
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what do intercalted discs produce throughout the heart?
|
syncitium
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what surrounds each cardiac muscle fiber ?
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a network of fine reticular and collagenous fibers
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is the myofibril arrangement of cardiac muscle more similar to smooth or skeletal muscle?
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skeletal
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what are the specialized impulse conducting fibers of cardiac muscle called?
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purkinje fibers
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what do purkinje fiber nuclei look like?
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centrally located nucleus surrounded by granular (rich in glycogen) sacroplasm.
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how are the myofibrils arranged in purkinje fibers?
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fewer than other muscles and are located in the peripheral portion.
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what do smooth muscle cells look like?
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elongated, spindle-shaped
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what do smooth muscle nuclei look like?
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single centrally placed nucleus
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what does the sacroplasm of smooth muscle look like?
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stains acidophillic
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individual myocytes of smooth muscle are surrounded by ____ produced by myocytes rather than by fibroblasts?
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a fine network of reticular fibers
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the sacroplasm of smooth muscle contains numerous___ myofilaments whereas____ myofilaments are sparse.
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numerous thin myofilaments
sparse thick myofilaments |
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the thin myofilaments of smooth muscle contain what two things?
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actin and tropomyosin
LACKS TROPONIN |
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thick myofilaments of smooth muscle are composed of?
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myosin
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are thick and thin filaments arranged in a highly ordered pattern as in skeletal muscles?
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no
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what in the sacroplasm of smooth muscles serve as anchor sites for myofilaments?
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dense bodies
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what in the sacroplasm of smooth muscles further link the dense bodies into a meshwork array?
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intermediate filaments
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what are present in the cell membrane of smooth muscles and play a role in calcium transport?
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vesicles
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where is cardiac muscle found?
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in the walls of the heart
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what does smooth muscles look like?
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non-striated
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where is smooth muscle found int eh body?
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most of the viscera, walls of the GIT, uterus, urinary bladder, etc.
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what is the nervous system responsible for?
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regulates the animals ability to respond appropriately to changes in its environment
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what are the components of the nervous system?
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neurons and supportive cells- neuorglia
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The CNS includes the
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brain and spinal cord
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the PNS includes the
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cranial and spinal nerves
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the autonomic nervous system innervates the
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visceral organs
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the layers that surround the CNS and the roots of the PNS are the
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meninges
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what are perikaryon's
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nerve cell bodies
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what are neuronal processes?
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axon and dendrites
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what kind of neurons have one axon and several dendrites?
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multipolar
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what kind of neurons have one axon and one dendrite
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bipolar cells
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what kind of neuorns have one process (axon) and bifurcates into a central and peripheral branches?
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unipolar
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where are unipolar neurons found?
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sensory ganglia
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where are bipolar neurons found?
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retina
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what does nervous nuclei look like when not in autonomic ganglia?
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centrally placed
ovoid or spherical relatively euchromatic prominent nucleolus |
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what may be evident in the nucleolus of nervous cells?
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sex chromatin (Barr body) may be evident in the vicinity of the nucleolus in cats and rodents
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where is the nucleus located in autonomic ganglia?
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eccentrically placed nucleus
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what aka pseduopolar neuron?
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unipolar neurons
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what kind of cytoplasmic substances are present in neural cells ?
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Nissl substance
microtubules prominet golgi complex numerous mitochondria lipofuscian pigments |
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what is Nissl substance ?
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aggregation of rER and ribosomes
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what is the role of neurofilaments?
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cytoskeleton
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what is the rold or microtubules in neural cells?
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rapid transport of membrane bound organelles
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what is the role of the prominent golgi complex in neural cells?
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secretes neurotransmitter and hormones
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why are there lipofuscian pigments
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they are residue of lysosomal activity
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what are highly branched processes designed to receive numerous synaptic contacts from other neurons ?
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dendrites
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what do dendrites contain in their cytoplasm?
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NO GOLGI BODIES
nissl substance neurofilaments microtubules mitochondria and lipofuscin pigment |
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what are the synaptic sites like of dendrites?
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thick band of electron-dense material associated with plasmalemma
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what does the dense material of synaptic sites consist of?
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proteins- receptor channels, enzymes, etc.
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what is the dense material of synaptic sites responsible for?
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postsynaptic activity
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what are gemmules? do all neurons have them?
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dendritic spines, not all some neurons have them
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what do gemmules consist of ?
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a membrane sac containing dense material
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what is the axon?
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a relatively long cytoplasmic process, originates from the axon hillock of the cell body and ends in terminal branches
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what are the terminal branches of axons called?
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telodendrites
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what is the cytoplasm of axons devoid of?
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chromatophillic substance
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what are the terminal branches of axons called?
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terminal bulbs
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where are neurotransmitter molecules packaged and stored?
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within a synaptic vesicle
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where are neurotransmitter molecules released from?
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terminal bulb of axon
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in addition to synaptic vesicles, terminal branches may contain what other things?
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secretory vesicles that store neuromodulators and neurohormones
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what are neuromodulators?
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agents that augment neurotransmitter effect
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what are neurohormones
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oxytocin and vasopressin in hypothalamic neurons
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define a synapse
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the sites wehre contract occurs between two neurons or between neurons and other effector cells (muscle and gland cells)
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where are synapses formed?
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by presynaptic terminal (telodendron), synaptic cleft (intercellular space), and post synaptic terminal on dendrites (gemmules)
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what is a telodendron?
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presynaptic terminal
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what is intercellular space?
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synpatic cleft
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what is gemmule?
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post synaptic terminal on dendrite
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what are the 3 types of synapse?
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axo-somatic
axo-dendritic axo-axonic |
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what is an axo-somatic synapse?
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axon with nerve cell body
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what is an axo-dendritic synapse?
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axon with dendrite
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what is an axo-axonic synapse?
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axon with axon
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what is the function of neurogilial cells?
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provide structural and functional support
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what are the four neuroglial cells in the CNS?
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astrocytes
oligodendrocytes microglial cells ependymal cells |
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where are the neuroglial cells derived from in the CNS?
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microglial- mesoderm
other 3- neural ectoderm |
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what are the neuroglial cells in the PNS?
|
neurolemmocytes- schwann cells
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where are neurolemmocytes derived from?
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neural crest
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what is the function of neurolemmocytes?
|
myelinate axons and become satellite cell in ganglia
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what do astrocytes look like ?
|
star-shaped with multiple radiating processes that contain glial filaments
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what do the glial filaments of astrocytes stain with?
|
silver stain
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what is the function of astrocytes?
|
to provide structural support by binding neurons to capillaries and to the pia mater
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what are astrocytes like in white matter?
|
their processes are long, slender and moderately branched- termed FIBROUS ASTROCYTES
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where are fibrous astrocytes located?
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in white matter
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what are astrocytes like in grey matter?
|
processes are shorter and highly branched- termed PROTPLASMIC ASTROCYTES
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where are protoplasmic astrocytes located?
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grey matter
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what are astrocyte feet and their function?
|
astrocyte processes terminate in an expansion called feet which cover the endothelium of blood vessels with the brain and spinal cord and form the BBB. Helps to maintain the electrolye balance in the CNS.
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what are oligodendrocytes?
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glial cells that have few small processes that wrap around axons in CNS, producing a myelin sheath which provides electrical insulation
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what are neurolemmocytes
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or schwann cells wrapped around axons of the PNS- produce myelin sheath.
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what are nodes of ranvier
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where the myelin sheath is interrupted at the juncture of adjacent neurolemmocytes, formining uninsulated sites called N.O.R.
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what is internode?
|
the myelin sheath between nodes of ranvier
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what do microglial cells look like?
|
small, elongated cells with elongated chromatophillic nucleus and short irregular processes.
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what is the function of microglial cells?
|
phagocytic cells
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where are microglial cells derived from?
|
bone marrow. and neural ectoderm
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what do ependymal cells look like?
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ciliated, cuboidal or columnar cells
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what do ependymal cells line?
|
ventricles of the brain and central canal of the spinal cord
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what do ependymal cells do physically?
|
facilitate the movement of cerebrospinal fluid
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what is derived from ependymal cells?
|
choroid plexus
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what do ependymal cells produce?
|
CSF
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|
a nerve fiber consists of an axon enveloped by neurolemmocytes and surrounded by a thin layer of connective tissue fibers called the______
|
endoneurium
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nerve fibers are organized into fasciles enveloped by collagenous CT called _____
|
perineurium
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|
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the multiple fasciles of a nerve are bound together by CT called
|
epineurium
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what are the nerve fibers of the PNS?
|
afferent and efferent
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|
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what are ganglia?
|
aggregations of nerve cell bodies along the course of peripheral nerves, supported by CT
|
|
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sensory ganglia are associated with what two ganglia?
|
cranial ganglia- assoc. with CR. nerves
spinal ganglia- dorsal root of spinal nerve |
|
|
what type of neurons do sensory ganglia have?
|
unipolar with a single axon which bifrucates into central and peripheral branches
|
|
|
each cell body of sensory ganglia is tightly encapsulated by?
|
ganglionic gliocytes (satellite cells)
|
|
|
what are autonomic ganglia?
|
accumulations of multipolar nerve cell bodies along the course of autonomic nerves.
|
|
|
what is characteristic of autonomic ganglia?
|
eccentric nuclei, marginally distributed Nissl granules and are loosely encapsulated by ganglionic gliocytes (satellite cells)
|
|
|
what is tightly encapsulated by ganglionic gliocytes, loosely?
|
tightly- sensory ganglia
loosely- autonomic ganglia |
|
|
exteroreceptors are afferent terminations where?
|
body surface
|
|
|
enteroreceptors are afferent terminations where?
|
viscera
|
|
|
proprioceptors are afferent terminations where?
|
musculoskeletal structures
|
|
|
what the three types of stimuli for afferent receptors?
|
mechanoreceptors
chemoreceptors thermoreceptors |
|
|
what are two examples of nonencapsulated afferent receptors?
|
free nerve ending
tactile corpuscles |
|
|
what are 5 examples of encapsulated afferent receptors?
|
Meissners
Lamellar (paccinian) bulbous (Krause's) or genital neurotendinous spicules neuromuscular spicules |
|
|
what are afferent terminations also known as?
|
receptors
|
|
|
what are efferent terminations also known as?
|
neuromuscular synapse
|
|
|
what do neuromuscular synapses consist of?
|
presynaptic neuronal end plate overlying a postsynaptic muscle sole plate in the mid region of the muscle fiber
|
|
|
how is a motor end plate formed?
|
by very short branches within a circumscribed zone (plate) at the end of one terminal branch of an efferent neuron.
|
|
|
where does each motor end plate lie?
|
in the corresponding trough of the muscle sole plate
|
|
|
how large is the neuromuscular gap?
|
40-50 nm
|
|
|
what does motor end plate cytoplasm contain?
|
many mitochondria and synaptic vesicles that contain acetylcholine
|
|
|
what happens to the acetylcholine at motor end plates?
|
AcH releases at active sites, diffuses across the neuromuscular gap and binds to postsynaptic receptor site, leading to muscle fiber depolarization.
|
|
|
what is in grey matter of spinal cord
|
nerve cell bodies
|
|
|
what type of neurons are in the ventral grey horn?
|
efferent neurons
|
|
|
what type of neurons are in the dorsal grey matter (horn) of the spinal cord?
|
interneurons
|
|
|
what type of neurons are in the lateral grey matter (horn) of the spinal cord?
|
sympathetic neurons
|
|
|
what are the 3 white matter processes?
|
dorsal, ventral, and lateral funiculi. Ascending and descending tracts.
|
|
|
what is the central canal of the spinal cord lined by?
|
ependymal cells
|
|
|
how is the white matter of the spinal cord seperated dorsally and medially?
|
dorally- dorsal median septum
ventrally- ventral median fissure |
|
|
what does the cerebral cortex present?
|
gyri and sulci
|
|
|
what are the 6 histological layers from superficial to deep present in the grey matter of the cerebral cortex?
|
molecular layer
external granular layer external pyramidal layer internal granular layer internal pyramidal layer fusiform layer |
|
|
what is the molecular layer of the cc composed of?
|
processes of stellate or pyramidial neurons (neuropil), arranged tangentially
|
|
|
what are neuropil?
|
pyramidal neurons
|
|
|
what is the external granular layer of cc composed of?
|
small pyramidial neurons
|
|
|
what is the external pyramidal layer composed of?
|
small and medium pyramidal neurons
|
|
|
what is the internal granular layer of the cc composed of?
|
small steallate neuorns
|
|
|
what is the internal pyramidal layer composed of?
|
medium to large pyramidal neuons that send axons to the white matter.
|
|
|
what is the fusiform layer of the cc composed of?
|
many spindle shaped neurons
|
|
|
what is the white matter of the cerebral cortex composed of?
|
nerve fibers going to and coming from the cortex.
|
|
|
how are the grey and white matter arranged in the cerebellum?
|
outer grey and inner white matters are arranged in a highly folded structure- FOLIA
|
|
|
what are the three layers of the cerebellar cortex?
|
outer molecular layer
inner granular layer intermediate purkinje cell layer |
|
|
what is the outer molecular layer of the cerebellum composed of?
|
neuropil arranged horizontally
|
|
|
what is the inner granular layer of the cerebellum composed of?
|
densely packed small neurons with intensely stained nuclei
|
|
|
what is the intermediate purkinge cell layer of the cerebellum composed of?
|
a single layer of piriform cells, which send their ramified dendrites into the molecular layer, and the axons into the white matter.
|
|
|
what is white matter composed of in the cerebellum cortex?
|
nerve fibers
|
|
|
what are the meniges and spaces from outside to inside?
|
epidural space
dura mater subdural space aracnoid subarachnoid space pia mater |
|
|
what are the leptomeninges?
|
arachnoid and pia mater, collectively.
|
|
|
CSF is produced where?
|
choroid plexuses in ventricles, exits through the lateral apeture and enters the subarachnoid space.
|
|
|
what is the purpose of CSF?
|
provides physical protection for the brain and spinal cord.
|
