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321 Cards in this Set
- Front
- Back
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What are the two broad categories of glands?
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Endocrine and Exocrine
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Describe Endocrine Glands
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Synthesize and release hormones to be transported in the blood to target cells or released into ECF to exert paracrine or autocrine effects
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Describe Exocrine Glands
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Secrete product in epithelial-lined ducts. Secretions may be modified while in duct
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What is clinically significant about glands?
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Tumors (adenomas and adenocarcinomas) can develop from glands
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How are exocrine glands classified
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1. Type of Secretion
2. Mode of Secretion 3. Cell numbers |
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What are the four types of exocrine gland secretions mentioned in class?
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1. Mucous Glands
2. Serous Glands 3. Mixed Glands 4. Sebaceous Glands |
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What are two examples of mucous glands?
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Goblet Cells and the mucous cells of the stomach
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Describe Mucous glands
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Thick, protective secretions called mucin.
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Describe serous glands
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Watery secretions enriched with enzymes
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What are two examples of serous glands?
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Parotid gland and exocrine pancreas
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What are the 3 modes of secretion of exocrine glands discussed in class?
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1. Merocine
2. Apocrine 3. Holocrine |
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Describe merocine secretion
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Exocytosis, NO LOSS of PM/cytoplasm
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What is the most common mode of secretion in exocrine glands?
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Merocrine
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Describe apocrine glands
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Product is released along with apical cytoplasm/PM
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Give one example of an Apocrine gland
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Mammary glands (lactating) - release lipids in this fashion
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Describe holocrine glands
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The entire cell and its secretory product is released
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Give on example of a holocrine gland
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Sebaceous glands
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How are exocrine glands classified by cell number?
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1. Unicellular exocrine glands
2. Multicellular exocrine glands |
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Describe unicellular exocrine glands
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Individual secretory cells are found in the epithelium
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Give an example of a unicellular exocrine gland
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Goblet cell found in GI tube and respiratory airways
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Describe multicellular exocrine glands
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Organized into secretory sheets or tubules with with no ducts, or into secretory units and duct systems
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How are multicellular exocrine glands further classified?
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Shape of secretory units and nature of duct system
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What are the different shapes of secretory units?
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Acinus (alveolus)
Tubular Mixed |
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What are "simple branched" secretory units?
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Units that branch from a single duct
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How are multicellular exocrine glands classified by duct system?
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Simple or Compound
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What surrounds large multicellular glands?
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Collagenous capsule
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How are lubules formed within a large multicellular gland?
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Septa from the capsule extends into the gland, dividing it into lobes, and then continues to form lobules
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What are intralobular ducts?
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Ducts found within a lobule of an exocrine gland
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Where are intralobular ducts found?
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In the connective septa that separate lobules
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Into what do intralobules ducts drain?
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Interlobar (lobar) ducts
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What are myoepithelial cells (i.e. basket cells)?
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Contractile cells derived from epithelium. Contain actin and myosin
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What type of intermediate filament do epithelial-derived cells contain?
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Cytokeratin
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How are myoepithelial cells connected to epithelial cells?
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Desmosomes and gap junctions
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When myoepithelial cells contract, what happens?
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Secretion from gland
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How is the parotid gland classified?
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Compound acinar
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Is the parotid gland a mucous, serous, or mixed gland?
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Serous
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Name the clinical significance of the parotid gland
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Mumps parotitis
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How are the nuclei of the parotid gland cells oriented?
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Centrally and slightly toward the apical side
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How is the submandibular gland classified?
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Compound tubuloacinar
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Is the submandibular gland a mucous, serous or mixed gland?
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Mixed, primarily serous
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In the submandibular gland, what do serous demilune cells secrete?
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Lysozyme
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Where is the synthetic machinery of a goblet cell located?
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Its stem
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Regarding duct nomenclated, which is smaller, intercalated or striated ducts?
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Intercalated
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What kind of cells are found in an intercalated duct?
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Low cuboidal
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What do intercalated ducts drain into?
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Straited ducts
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What kind of cells are found in a striated duct?
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Cuboidal to columnar
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What gives striated ducts their striated apperance?
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Accumulation of mitochondria on the basal domain of the cells
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What to striated ducts join to form?
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Intralobular ducts
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What kind of cells are found in an intralobular duct?
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Cuboidal to columnar
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What do intralobular ducts join to form?
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Interlobular ducts
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What kind of cells are found in interlobular ducts?
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Pseudostratified columnar
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What do intralobular ducts join to form?
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Lobular ducts
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What kind of cells are found in lobular ducts?
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Stratified columnar
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What do lobular ducts join to form?
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the Main duct
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Define parenchyma as it pertains to exocrine glands
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The epithelial components of all branched exocrine glands (secretory acini and ducts)
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If you see a mix of mucous and serous cells on the practical, what kind of gland will it be?
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Tubuloacinar gland
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What secretes lactoferrin?
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Intercalated duct cells and some acinar cells
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What does lactoferrin do?
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Binds iron, which is essential for bacterial growth, thus lactoferrin retards bacterial growth
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How is the sublingual gland classified?
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comound tubuloacinar
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Is the sublingual gland a mucous, serous or mixed gland?
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Mixed, primarily mucous. Any serous cells present exist as demilunes
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What is a noted difference between intralobular ducts of the sublingual gland versus other salivary glands?
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In the sublingual gland, they are less developed.
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What is Sjogren Syndrome?
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An autoimmune disease characterized by dry eyes (keratoconjunctivitis sicca) and dry mouth (xerostomia). The parotid gland is enlarged in 50% of the cases. Patients have difficulty swallowing and cracked lips, etc.
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What are some general clinical significances of salivary diagnostics?
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Antibodies to HIV-1 and HIV-2 are present in saliva of infected patients. Also valuable for oral and breast cancers
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How is the pancreas classified in terms of exocrine gland?
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Compound acinar
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Name three distinguishing features of the pancreas discussed in class
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Islets of Langerhans
Centroacinar cells Absence of striated discs |
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What is the clinical relevance of the pancreas discussed in class?
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Pancreatitis (acute and chronic). Inflammation of the pancreas, often related to alcohol abuse
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Give an example of a simple branched acinar gland
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Sebaceous glands of the skin
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Give an example of a simple tubular gland
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Intestinal Glands
***NO DUCTS IN SIMPLE TUBULAR! |
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Are there ducts in simple tubular glands?
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NO!
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Give an example of a simple coiled tubular gland
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Sweat glands in skin
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Give an example of a simple branched tubular gland
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Glands of the stomach and duodenal
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Give an example of a compound acinar gland
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Pancreas, Parotid gland
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List the 5 functions of the skin discussed in class
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1. Protection (microbes, dehydration, etc)
2. Thermoregulation (sweating) 3. Reception (pain, pressure, touch, temp) 4. Absorption (UV rays) 5. Excretion (by sweat glands) 4. |
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Where is thick skin found?
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Palms and soles
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What is present in thin skin but NOT in thick skin?
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Hair follicles, arrector pili muscles, sebaceous glands
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Are there sweat glands in thick skin?
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YES
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What type of skin is more common, thin or thick?
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Thin
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How many major layers of the skin are there and what are they?
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TWO
1. Epidermis (superficial) 2. Dermis |
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What kind of epithelium is found in the epidermis?
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Stratified squamous keratinized epithelium
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What kind of cells are most common in the epidermis?
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Keratinocytes
*Skin renewal by mitotic activity at night, desquamate ~20-30 days |
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Name the three types of nonkeratinocytes in the epidermis
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Langerhans (Dendritic) Cells
Merkel Cells Melanocytes |
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What do Langerhans (Dendritic) cells function in?
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Defense system (antigen-presenting cells)
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Describe dendritic cells
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Have long, thin cytoplasmic processes which extend into the intercellular space. Contain Birbeck granules (vermiform granules)
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What are Birbeck granules?
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Tennis-racket in apperance, these cells are found in Langerhan's (dendritic) cells.
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What strata do dendritic cells reside?
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All, but mainly Spinosum. Also found in epithelium lining in oral cavity, esophagus, and vagina
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From what are dendritic cells derived?
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Precursors in the bone marrow which leave the bloodstream and take up residence in the epidermis where they differentiate into Langerhan's cells
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What are Merkel Cells?
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Cells that function in mechanoreceptors (tactile receptors)
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Where are Merkel cells found in the body?
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Fingertips, oral mucosa, base of hair follicles
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What strata are Merkel cells found in?
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Stratum basale
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How are Merkel cells attached to keratinocytes in the stratum basale?
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Via desmosomes
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What is the main function of melanocytes?
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Form umbrellas to protect DNA from UV damage. Synthesize a pigment, melanin
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What are the 5 strata of thick skin?
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Basale
Spinosum Granulosum Lucidum Corneum |
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Describe the stratum basale
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A single layer of cuboidal to low columnar basophilic cells with prominent nuclei
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How are the cells of the strautm basale held together?
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Desmosomes attach the cells to each other and to cells in the overlying stratum spinosum
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Is the stratum basale renewed (undergo mitosis)?
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YES
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How do cells of this layer attach to the BM?
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Hemidesmosomes
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Describe the stratum spinosum
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The thickest stratum w/living cells, containing interdigitating processes b/t cells giving it a railroad apperance. "Prickle Cell" Desmosomes help hold cytoplasmic processes together
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Does mitosis occur in the stratum spinosum?
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Yes, on the basal layer
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Describe the stratum granulosum
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Contains living cells, but in this layer they begin dying. Keratohyalin granules and membrane coating granules are released onto the cell surface
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Describe the stratum Lucidum
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A light staining layer, thin, follows the contour of stratum granulosum
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Name two things in the stratum lucidum that have not been present in any layer until now
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Keratin filaments and Eleidin
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What layers are keratin filaments found?
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Stratum Lucidum and Stratum Corneum
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Describe the stratum corneum
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A thick layer of flat, keratinized, dead cells. No desmosomes here
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Which layer forms a waterproofing substance?
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Stratum Granulosum. Exocytosis of lipid-rich substance forms sheets of waterproof material, which prevents diffusion of nutrients in extracellular space, thus starving superficial strata
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What are the strata of the thin skin?
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Corneum, spinosum, basale
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What constitutes the dermis?
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Consists of dense irregular collagenous CT
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What are the two layers of the dermis?
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Papillary Layer (superficial)
Reticular Layer |
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What is Vitiligo?
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A condition characterized by a decrease or complete loss of melanocytes due to formation of antibodies against melanocytes. Patients have patches of light and dark epidermis
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What is albinism?
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A condition where defective melanocytes do not synthesize melanin due to a defect or absence of tyrosinase.
People with albinism have light-colored hair, eyelashes, eyebrows, and a light/pale complexion. |
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What is the clinical significance of malignant melanoma?
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Heredity light skin mixed with excessive sunlight can predispose one to damaging effects of UV light, resulting in irregular nodules on the skin.
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Describe basal cell carcinoma
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Due to chronic sun exposure. Grows slowly and rarely metastasizes. Once diagnosed, it can be excised and treated.
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What is Ichthyosis?
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A genetic disorder apparent around time of birth, characterized by excessive production of keratin (hyperkeratosis). Fish-like scales on skin
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Describe the stratum corneum
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A thick layer of flat, keratinized, dead cells. No desmosomes here
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Which layer forms a waterproofing substance?
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Stratum Granulosum. Exocytosis of lipid-rich substance forms sheets of waterproof material, which prevents diffusion of nutrients in extracellular space, thus starving superficial strata
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What are the strata of the thin skin?
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Corneum, spinosum, basale
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What constitutes the dermis?
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Consists of dense irregular collagenous CT
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What are the two layers of the dermis?
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Papillary Layer (superficial)
Reticular Layer |
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What is Vitiligo?
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A condition characterized by a decrease or complete loss of melanocytes due to formation of antibodies against melanocytes. Patients have patches of light and dark epidermis
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What is albinism?
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A condition where defective melanocytes do not synthesize melanin due to a defect or absence of tyrosinase.
People with albinism have light-colored hair, eyelashes, eyebrows, and a light/pale complexion. |
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What is the clinical significance of malignant melanoma?
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Heredity light skin mixed with excessive sunlight can predispose one to damaging effects of UV light, resulting in irregular nodules on the skin.
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Describe basal cell carcinoma
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Due to chronic sun exposure. Grows slowly and rarely metastasizes. Once diagnosed, it can be excised and treated.
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What is Ichthyosis?
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A genetic disorder apparent around time of birth, characterized by excessive production of keratin (hyperkeratosis). Fish-like scales on skin
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Describe the papillary layer of the dermis
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Thin layer of loose CT, rich in capillary networks, consists of elactic and reticular fibers, Meissner corpuscles and Krause end bulbs
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What are meissner corpuscles and what layer are they found in?
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They are mechanorecptors, found in the papillary layer of the dermis. They are especially present in lips, externa genitals, and nipple.
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Describe the reticular layer of the dermis
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Dense irregular CT, type one collagen fibers, thick elastic fibers. Contains hair follicles, arrector pili muscles, sebaceous and sweat glands, Pacinian and Ruffini corpuscles.
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What are Pacinian corpuscles are what layer are they found in?
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Detect pressure and vibrations, found in the reticular layer of the dermis
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What are Ruffini corpuscles and what layer are they found in?
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Detect tensile forces, especially present in the soles of the feet. Found in the reticular layer of the dermis
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What is the Hypodermis?
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A superficial fascial layer of loose CT deep to the dermis
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Is the Hypodermis a layer of the skin?
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NO
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What are the four glands of the skin discussed in class?
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Eccrine sweat glands
Apocrine sweat glands Sebaceous glands Mammary glands |
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How are eccrine sweat glands classified?
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Simple coiled tubular glands
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Where are eccrine sweat glands located?
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Deep in the dermis or hypodermis, scattered throughout the skin
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What is a major function of eccrine sweat glands?
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Thermoregulation
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What is the mode of secretion of eccrine sweat glands?
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Merocrine (no loss of PM/cytoplasm)
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What innervates eccrine sweat glands?
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Postganglionic sympathetic fibers
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What aids in secretion of products in eccrine glands?
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Myoepithelial cells surround the secretory segments and contract, squeezing out the product.
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Where are apocrine sweat glands found?
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Axilla, Areola of Nipple, Anal Region
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What is the mode of secretion in apocrine sweat glands?
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Merocrine (product only)
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How are apocrine sweat glands innervated?
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Sympathetic NS
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Describe apocrine glands and their product
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These glands have are larger than eccrine glands, have a wide lumen, through which they secrete an odorless product, however upon secretion, bacteria metabolize it and produce that sweaty smell.
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Are apocrine glands sensitive to hormones?
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Yes, they become active during puberty
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What is the mode of secretion for sebaceous glands?
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Holocrine (entire cell + product is secreted)
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What do sebaceous glands produce?
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The oily secretions of the hair
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Where are sebaceous glands found?
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In the dermis and hypodermis throughout the body, more numerous in the face and scalp
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Are sebaceous glands influenced by hormones?
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Yes, active after puberty
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Describe the hair bulb
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Has a root containing the matrix and dermal papilla. Surrounded by internal and external root sheaths, and then gives rise to the hair shaft
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Describe the internal root sheath layers (3)
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Henle's Layer (outer)
Huxley's Layer (Middle) Cuticle (inner) |
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Describe the hair shaft
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Medulla (inner)
Cortex (middle) Cuticle (inner) |
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What is the eponychium?
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The proximal nail fold (cuticle) of the fingernail
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What is the nail plate?
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Where you put nail polish
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Which is more acidic, arteriole or venous blood?
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Venous blood (pH 7.35)
Arterial blood (pH 7.4) |
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What are the functions of blood?
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Transport O2 and CO2
Transport nutrients, hormones, waste products, other chemicals Regulation of body temp, pH, and osmolality of body fluids Hemostasis Immunity |
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What are the elements of blood?
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Plasma, Formed elements, blood elements, serum (plasma-fibrinogen)
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What are the formed elements?
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Erythrocytes, Leukocytes, Platelets (thrombocytes)
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What are the blood element layers in a centrifuged tube?
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Hematocrit, buffy coat, plasma
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What is plasma?
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A yellowish fluid (color due to bilirubin) composed of 90% water. The other 10% is various compounds (proteins, hormones, electrolytes, and dissolves gases)
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What are the various proteins found in plasma?
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Albumin, Globulins, Clotting proteins, Complement factor, lipoproteins
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What is the function of albumin?
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Important in maintaining the colloid osmotic pressure
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What happens to the blood plasma on a high fat diet?
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Becomes whitish due to increased chylomicrons
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What does LDL function in?
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Transport of cholesterol from liver to body cells
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What does HDL function in?
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Transport of cholesterol from tissues to liver and steroid synthesizing cells
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What is the most common protein found in plasma?
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Albumin
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Describe the shape of RBCs
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biconcave disk
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Why is the shape of RBCs optimal for their function?
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Increases the surface area to volume ratio thus facilitating gaseous exchange
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Describe the intracellular components of RBCs
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Lacks typical complement of organelles to make space for hemoglobin and endogenous pigment
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What happens if your albumin levels are too low?
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Water leaves the capillaries and results in edema. Can be severe!
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How numerous are RBCs in the blood?
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VERY! 4-6 million per cubic mm
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How long do RBCs "live" b/4 being replaced?
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~120 days. About 2 million are lost and replaced every second
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What are the two major transmembrane proteins in RBCs?
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Glycophorin and Band-3
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What is the function of the two major proteins in RBCs?
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Glycophorin = unknown
Band-3 = Transports (antiport) HCO3- and Cl- across the PM. Increases the CO2 carrying capacity of erythrocyte |
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What is the most common mode of exocrine gland secretion?
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Merocrine
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Describe the cytoskeleton of RBCs
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Contains Band 4.1, Ankyrin, and Adducin to help anchor components.
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What is Hereditary Spherocytosis?
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A condition entailing defective spectrin destabilizing the cytoskeletal scaffolding causing the cell to become spherical, thus destroying the cell's carrying capacity. These cells are removed by the spleen, and thus leads to anemia, jaundice and splenomegaly
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What is Erythroblastosis fetalis?
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Rh- mother gives birth to Rh+ baby, 1st is fine, but when blood mixes, mom produces antibodies against the Rh antigen, so the second Rh+ baby will be attacked by the antibodies (which can cross the placenta)
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What are the major antigens found on the external surface of the RBCs?
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A, B, and Rh
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Explain blood typing
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Having a particular antigen makes you positive for it. For example having the A antigen makes you type A blood. If both A and B are present, you're AB and if neither are, you're O.
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What are Howell-Jolly bodies?
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Small basophilic nuclear fragments in the cytoplasm of RBCs. Present in patients w/severe hemolytic anemia, dysfunctional spleens or after splenectomy
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What are reticulocytes?
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Immediate precursor to mature erythrocyte. Specks of basophilia in cytoplasm due to clusters of ribosomes
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What does an increase in reticulocyte numbers indicate?
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A greater demand for oxygen (hemorrhage, move to higher altitude)
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What is the frequency of Leukocytes in the blood compared to RBCs?
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Much less populous. 5,000-10,000 per cubic mm (compared to 4-6 million RBCs)
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What are the 5 types of leukocytes described in class?
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Lymphocytes, Monocytes, Neutrophils, eosinophils, basophils
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Of the 5 types of leukocytes, which have specific granules?
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Neutrophils, eosinophiles and basophils
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Which type of leukocyte is the most abundant?
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Neutrophil
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Which type of leukocyte is the second most abundant?
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Lymphocytes
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Which type of leukocyte is the rarest?
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Basophils
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Which type of leukocyte has elevated levels with bacterial infections?
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Neutrophils
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Which type of leukocyte has elevated levels with parasitic infections?
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Eosinophils
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Which type of leukocyte has elevated levels with viral infection?
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Lymphocytes
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Describe the apperance of lymphocytes
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Small (~same size as RBCs), prominant nucleus
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What are the different types of lymphocytes?
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B lymphocytes, T lymphocytes, NK cells
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Which type of leukocyte gives rise to macrophages?
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Monocytes
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Describe the apperance of monocytes
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large cells, with a large kidney-shaped nucleus. Blue-gray in color
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What is the major function of neutrophils?
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Phagocytosis.
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Describe the apperance of neutrophils
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lobated nuclei. The older, the more lobated it is!
Has three types of granules: Specific (secondary) are pink, Azurophilic (primary) represent lysosomes, and Tertiary granules which degrade collagen |
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What is the function of basophils?
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Contain histamine, heparin, and other materials - inflammation responses, etc.
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Describe the apperance of basophils
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S-shaped nucleus obscured by darkly stained basophilic specific granules
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Describe the apperance of eosinophils
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Bilobed nucleus, specific granules stain dark pink to red
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What are platelets?
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cellular fragments derived from larger precursor cell
Lack nucleus but do have some organelles |
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What are the two areas within platelets?
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Peripheral (Hyalomere) and Internal (granulomere)
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Describe the Peripheral (hyalomere) area of a platelet
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Contain microtubules-tubular system allows platelet to communicate with extracellular environment in which it lives
Can release and uptake various molecules |
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Describe the internal (granulomere) area of a platelet
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Contain mitochondria and granules
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What are the different granules of the internal area of a platelet?
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Lamda granule
Alpha granules Delta granules Serotonin |
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What is the funtion of the alpha granules of the internal area of the platelet?
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storing and releasing platelet derived growth factor and procoagulation factors
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What is the funtion of the lamda granules of the internal area of the platelet?
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Houses lysosomes
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What is the funtion of the delta granules of the internal area of the platelet?
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Contains various substances
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What does serotonin do in the platelets?
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Vasoconstrictor
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What does the suffix "-cytosis" denote?
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an increase in number of cells
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What does the suffix "-penia" denote?
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a reduction in the number of cells
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What is a Dohle Body?
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Represents RNA derived from ER, basophilic bodies. Seen in infection and some other conditions
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What are the 2 major components of the cardiovascular system (as far as vascular biology is concerned)?
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Blood vascular system and Lymphatic vascular system
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How many tunics (layers) are there in blood vessels?
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Three
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What are the different tunics of blood vessels?
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Tunica Intima (innermost)
Tunica Media Tunica Adventitia (outermost) |
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Describe the general (and familiar) path of blood
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RA to RV to Pulmonary Circulation to LA to LV to Aorta to ateries to arterioles to capillaries (gaseous exchange) to venules to veins to SVC/IVC to RA
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What is the major function of the lymphatic system?
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Removeal of the net loss of fluid out of microcirculation into the tissue space. Must occur at the same rate that it enters the tissue
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The throacic duct drains _______ while the right lymphatic duct drains ________
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Thoracic Duct = Most of body
R Lymph Duct = right upper extremity, right thoracic area, right face, and right neck |
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Describe the tunica intima
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Simple squamous endothelium resting on the basal lamina. Is adjacent to the subendothelial CT layer.
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Describe the subendothelial layer of the tunica intima
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Occasional smooth muscle cells, internal elastic lamina composed of elastin. Fenestrated for diffusion
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Describe the tunica media
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Very prominent, with concentric layers of smooth muscle cells, variable amounts of elastin, reticular fibers, and proteoglycans. External elastic lamina is comprised of fenestrated elastin
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Describe the tunica adventitia
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Outer coat of CT, type one collagen and elastic fibers. Contains vessels and nerves
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What is the vasa vasorum?
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Vessels of the vessels. blood supply to the vessels. In arteries, supply the tunica adventitia and outer parts of the media, while in veins, supply closer to the tunica intima (due to deoxy blood in veins)
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Are arteris or veins more densely innervated?
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Arteries
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What layer can you find the nerves?
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In arteris, nerve endingsare found in the tunica adventitia, while in veins nerves are found in the tunica media as well
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What kind of nerves supply the vessels?
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Primarily sympathetics, very few receive parasympathetics as well.
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What direction do the flattened cells of the endothelium run in blood vessels?
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Long axis in direction of blood vessel
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What is the signature feature of the endothelium cells of blood vessles?
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Weibel-Palade bodies
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What do Weibel-Palade bodies contain?
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Clotting factors, tissue plasminogen activator (breaks down clots), interleukin 8 P-selectin, and other things!
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Are these endothelium cells connected?
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Yes, by junctional complexes
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What are metarterioles?
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Vessels b/t arterioles and capillaries, composed of discontinuous layer of smooth muscle
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What is the function of metarterioles?
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helps to regulate blood flow into the capillary bed (if tissue is active, they dilate and allow more bloow flow to this area, and if they cx, then not as much blood is needed)
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What is an arteriovenous shunt?
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anastomose
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Describe the tunica intima in capillaries
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endothelium and basal lamina
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Describe the tunica media in capillaries
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Don't have true tunica media, Pericytes relate to the position of this layer
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Describe the tunica adventitia in capillaries
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Very thin
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What are the 3 types of capillaries?
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Continuous
Fenestrated Sinusoidal |
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Describe continuous capillaries
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Tight junction, lack pores, cells contain numerous pinocytotic vesicles
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Where are continuous capillaries found?
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Brain, muscle, CT, exocrine glands
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Describe fenestrated capillaries
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Contain fenestrae (pores) in the walls of endothelial cells (usually contain diaphragms to help regulate passage).
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Where are fenestrated capillaries?
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Areas of rapid exchange of substances b/t blood and tissues: kidney, both glomerulus (no diaphragm) and nonglomerular, endocrine glands, intestines
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Describe sinusoidal capillaries
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Discontinuous endothelial lining: large opneing b/t cells. Macrophages are associated with these vessels. Much larger than other kinds! Contain Pinocytotic vesicles to ferry things across. Several pinocytotic vesicles can join to together to form a large pore.
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Where are sinusoidal capillaries found?
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Areas of rapid exchange where entire cells can be exchanged (MASSIVE movement): red marrow, liver, spleen, adrenal cortex
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What are pericytes?
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Mesenchymal cells, contractile (blood flow regulation), send out extensions to surround the tunica intima.
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What are the two mechinisms for angiogenesis?
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Endothelial precursor cells (EPCs)
From pre-existing vessels |
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Which mechnism(s) of angiogensis does a tumor employ?
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Both (EPCs and pre-existing vessels)
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How do EPCs function?
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- Replace lost endothelial cells
- Re-endothelization of vascular implants - Neovascularization of ischemic organs, wounds, and tumors |
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What must take place in order for angiogenesis from pre-existing vessels to occur?
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Vasodilation/increased permeability
Degradation of basal lamina Migration and proliferation of endothelial cells Formation of endothelial capillary tube Elaboration of BL and recruitment of periendothelial cells (pericytes or sm cells) |
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How does vasodilation/increased permeability occur?
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- NO causes dilation
- Increased vascular permeablility induced by VEGF (Vascular endotheliual GF) of parent vessel |
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How does degradation of the basal lamina take place?
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Metalloproteinases of the parent vessel. Plasminogen activator causes loss of cell-to-cell contact
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How can endothelial cells migrate/proliferate?
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Since their contact has been disrupted by proangiogenic factors
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Would you want to promote or inhibit angiogenesis in the clinical case of myocardial ischemia?
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Promote
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Would you want to promote or inhibit angiogenesis in the clinical case of Hemangiomas?
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Inhibit
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Would you want to promote or inhibit angiogenesis in the clinical case of birth control?
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Inhibit
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Would you want to promote or inhibit angiogenesis in the clinical case of atherosclerotic plaque/neovascularization?
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Inhibit
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Would you want to promote or inhibit angiogenesis in the clinical case of reconstructive surgery/wound healing/fracture repair?
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Promote
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Would you want to promote or inhibit angiogenesis in the clinical case of cerebral ischemia?
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Promote
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Would you want to promote or inhibit angiogenesis in the clinical case of Rheumatoid arthritis?
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Inhibit
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Would you want to promote or inhibit angiogenesis in the clinical case of peripheral ischemia?
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Promote
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Would you want to promote or inhibit angiogenesis in the clinical case of ocular neovascularization?
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Inhibit
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Would you want to promote or inhibit angiogenesis in the clinical case of tumor growth/metastases?
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Inhibit
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Would you want to promote or inhibit angiogenesis in the clinical case of transplantation of islets of langerhans?
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Promote
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What are some important signals in proliferation/migration mechanisms?
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VEGF, Ang2, FGF-2
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What is the purpose of forming endothelial capillary tubes?
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To stabilize the newly formed cells of the new capillary
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What is the function of the Tie2 receptor?
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Binds to Ang1, which helps recruit paraendothelial cells (after formation of basal lamina).
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What is PDGF – platelet derived growth factor?
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Helps repair and form new blood vessels by recruiting sm cells
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Are blood vessels dynamic or static in terms of composition and structure of the walls?
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VERY DYNAMIC!
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What are the compensatory responses of a vessel to increased BP?
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Hypertrophy of sm
Collagen and elastin synthesis is enhanced |
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What are the compensatory responses of a vessel to decreased BP?
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sm atrophy and apoptosis
Degradation of collagen and elastin |
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What is the clinical significance of a heart Bypass using the great saphenous vein?
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We can take a vein from a low stress area, put it in a high stress area, and it will adjust and compensate to its environment.
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What are the three layers of the heart?
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Endocardium (tunica intima)
Myocardium (tunica media) Epicardium (tunica adventitia) |
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What are the layers of the Endocardium?
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1. Endothelium (simple squamous) and basal lamina
2. Subendothelial layer (elastic fibers, collagen fibers, sm cells) 3. Subendocardium (loose CT, small blood vessels, nerve fibers, Purkinje fibers (ventricals only!!)) |
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What are the various cardiocytes of the Myocardium?
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Contractile, myoendocrine, and specialized conductive
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What is the significance of the cardiac skeleton?
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It is the dense CT where cardiac muscle and valves are anchored. It alss isolates electrical activity of the atria and ventricles so conduction follows a specific pathway (ensures the atria and ventricles contract at proper times)
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Do the cusps of the AV valves contain blood vessels?
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No
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What are the three layers of cardiac valves?
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(a) Spongiosa – loose CT and endothelium
(b)Fibrosa – central core and denser irregular CT (c)Ventricularis – dense CT of elastic and collagen fibers and endothelium |
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What is the clinical significance of calcification of cardiac valves?
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Causees problems with closure, causing movement of blood when there should be none
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What is an Aschoff body?
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An area of inflammation in valves usually seen with rheumatic fever. Contains collagen fibers, T-lymphocytes, and swollen macrophages.
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Is is conduction generated in the heart muscle?
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specialized cardiac muscle cells maintain rhythmic activity of atrium and ventricle
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What is the conduction pathway in the heart?
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SA node to AV node to AV Bundle of His (All made of Purkinje cells) - (Common bundle, Right and left branches – terminal aspect of conduction pathway)
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What is the pacemaker of the heart?
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SA node
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Explain the decrease in resting HR as we age
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We lose up to 90% of our SA nodal cells by the age of 80
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Is the Bundle of His susceptible to damage in cases of sepsis or ishemia?
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Yes, as blood can get into the purkinje cells, which can lead to arrhythmia!
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Describe to size of the AV bundles
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Twice the diameter of cardiac muscle cells, fadter signal conduction
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How is it that infarcted myocardium has the potential to reconsititute and improve functioning?
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Cardiac stem cells
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What are Cardiomyoendocrine cells?
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Another type of specialized cell in the heart. Has a dark-staining nucleus and secretes hormones-atrionatriuretic protein, which allows the heart to control its blood volume and pressure
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What type of organ is the heart (in terms of the material covered in lecture?)
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An endocrine organ, as it secretes its own hormones
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What is the order of flow of lymph through lymphatic vessels (from smallest to largest)?
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Capillary-vessel-duct
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Define atherosclerosis
|
A form of arteriosclerosis characterized by fibrofatty lesions (atheromas) in the tunica intima. Lesions protrude into lumen, obstructing flow and weaken the tunica media.
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What are the consequences of atherosclerosis?
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Obstructued blood flow can lead to ischemia and/or infarction, weakened tunica media may lead to an aneurysm
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In athersclerosis, the tunic intima is thickened or thinned out?
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Thickened
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What happens to NO levels when the vessel wall is damaged and what is the consequence of the change?
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NO levels decrease, which allows for improved adhesion of leukocytes to vascular walls
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How do damaged endothelial cells help accelerate atherosclerosis?
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Can lead to the release of growth factors, adhesion molecules, cytokines due to damaged genes, thus improper expression
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How exactly, does the tunica intima become thickened in athersclerosis?
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Smooth muscle cells are recruited and migrate through fenestrations into the tunica intima where they proliferate.
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What are fatty streaks?
|
Pre-cursors to atherosclerotic lesions
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Are fatty streaks reversible?
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Yes
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Are atherosclerotic lesions reversible?
|
No, but certain changes in lifestyle can slow development
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Increased levels of what correlate with increased risk for ischemic heart disease (IHD) due to atherosclerosis?
|
Homocysteine
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Is LDL oxidized before or after it is engulfed by macrophages?
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Before. Cannot be engulfed otherwise. Thus, preventing the oxidation of LDLs could potentially prevent the formation of athersclerotic lesions
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What are foam cells?
|
Once oxidized, macrophages start phagocytosing the lipid material of LDLs; the lipid material washes out w/tissue preparation giving a “foamy” looking cytoplasm
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Can smooth muscle cells form foam cells?
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Yes, but most foam cells are macrophages
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How are smooth muscle cells recruited into the subendothelial compartmet?
|
Various growth factors and cytokines are released from platelets, endothelial cells, and macrophages
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How do smooth muscle cells differ b/t ones in their normal "home" (tunica media) and those that have been recruited into the subendothelial compartment?
|
Smooth muscle cells in tunica media have contractile phenotype, but once in intima, they change to become synthetic (make ECM) and proliferative (cells proliferate).
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What is a common consequence of atherosclerosis beneath the renal arteries?
|
Aortic Aneurysm
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Which coronary artery is termed the "Widowmaker" and why?
|
Anterior interventricular branch of the left coronary artery because it's the most common artery involved in producing a critical stenosis that results in a cardiac event (50% of cases). It supplies most of the left ventricle, about 2/3 of the interventricular septum, and surrounding Purkinje fibers.
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What are the 2nd and 2rd most common coronary arteries involved in stenosis and cardiac events?
|
2nd most = right coronary artery (30-40%)
3rd most = circumflex (15-20%) |
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What are the three layers of the heart muscle from innermost to outermost?
|
endomyocardium (inner), midmyocardium (middle), and epimyocardium (outer).
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Which layer of the heart tissue has the greatest demand for oxygen and why?
|
• The inner heart cells have a greater need for oxygen than the outer heart cells due to greater stresses placed on the inner heart wall, increasing oxygen consumption of those cells.
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Explain the wavefront phenomenon.
|
If you occlude an artery supplying a certain part of the heart wall, the first place you see ischemic damage/necrosis is the endomyocardium, next the midmyocardium may be involved, and lastly the outer wall may become involved if left long enough (with all three, it is the wave-front phenomenon of ischemic necrotic damage and considered transmural - destroyed entire thickness of myocardium)
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|
True or false: Vessels are the only site for aneurysims.
|
False - ventricles can too
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|
A hemorrhagic stroke is typically caused by a(n) ____
|
embolus
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A nonhemorrhagic stroke is typically caused by a(n) ____
|
thrombus
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|
Serous demilunes are found in what type of glands?
|
Mixed (mucous and serous) ONLY
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|
What is the hallmark microscopic feature of ischemic neurons?
|
The color change of cytoplasm from blue to RED
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|
How are lymphoid organs classified?
|
Primary (central) or Secondary (peripheral)
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|
Define a Primary (Central) Lymphoid organ
|
The site of development and maturation of lymphocytes into immunocompetent cells that will go out to "seed" secondary lymphoid organs.
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|
What are some examples of primary (central) lymphoid organs?
|
Fetal liver, bone marrow (both pre- and postnatal), Thymus.
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Define a secondary (peripheral) lymphoid organ
|
Site of formation of immunological defense against antigens or pathogens.
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|
Give some examples of secondary (peripheral) lymphoid organs
|
Lymph nodes, MALT, spleen, postnatal bone marrow
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|
What is MALT?
|
Mucosa-Associated Lymphoid Tissue. Includes GALT (Gut-assoc. lymphoid tissue), BALT (bronchus assoc. lymph. tissue) and the tonsils
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|
In general, what is lymphoid tissue?
|
A very cellular tissue with a lot of lymphocytes
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|
Where do B-lymphocytes originate?
|
Bone marrow
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Where do T-lymphocytes originate?
|
Thymus
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Where are stem cells for both B and T lymphocytes found?
|
Bone marrow
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