Studied by 5 people
what are the 3 layers of the basement membrane and what tissues are they made of?
basal lamina- lamina lucida, lamina densa - epithelial cells reticular lamina - connective tissue cells
lamina propria
connective tissue found under basement membrane
what are the layers that make up the mucosal layer?
epithelium, lamina propria, muscularis mucosae
does epithelial tissue or connective tissue have direct blood supply?
epithelial do not, while most connective do
can epithelial cells undergo cell division?
yes they do undergo cell division
is extracellular matrix associated only with connective tissue?
no it's present in multiple cells
what is extracellular matrix made of?
fibers and ground substance
what are the 3 types of fibers in extracellular matrix?
elastic fibers, collagen fibers, reticular fibers
what are the 3 structural categories of collagen fibers and where do the collagen types fall?
FIbrillar collagens - types I,II,III network/sheet-forming collagens - type IV linking/anchoring collagens- type VII
what type of collagen is located in the basal lamina?
anchoring/linking collagens
which nutrient is required for synthesis of collagen?
vitamin C
what type of collagen is found in reticular fibers?
type III
how does elastin differ from collagen?
its more diverse - it's made of amino acids
how far can an elastic/collagen fiber stretch beyond its resting length?
elastic can stretch 50%, fibrillar can stretch 5-10%
genetic mutations in collagen or elastin lead to which diseases?
blue sclera, osteogenesis imperfecta bleeding gums, loss of teeth, rupture of blood vessels, skin wounds fail to heal, weakened bones
alpha1-antitripsin deficiency affects which type of protein fiber?
elastin- body degrades elastin prematurely due to excess elastase activity lung disease common
which large protein molecules are found in the ground substance of ECM?
glycosaminoglycans (GAGs), proteoglycans, glycoproteins, water
what are proteoglycans made of?
hyaluronic acid and sulfated glycosaminoglycans GAGs bristles on a protein brush core
what are the most common GAGs?
what impacts does the negative structure of GAGs have on its function?
negative charges repel each other and are slippery to slide past each other
what is the difference between a proteoglycan monomer and aggregate?
proteoglycan monomer is singular bottle brush structure, aggregate is many monomers on a hyaluronic acid backbone attached to cell surface
what are the functions of proteoglycans within the ECM?
they resist compression and are hydrophilic to attract positively charged ions and water for rehydration
what are the 3 binding domains for adhesive glycoproteins?
fibronectin, laminin,
what is the main adhesive protein in connective tissue?
fibronectin
what is the main adhesive protein in epithelial tissue?
laminin
how does the ECM prevent or slow down infections?
what is extracellular fluid? how does its composition compare to that of blood plasma?
body fluid that is not contained in cells blood plasma
what are the 5 types of cell junctions discussed in lecture?
gap junctions, desmosomes, tight junctions, hemidesmosomes, adherens junction
which type of cell junction is generally found holding epithelial cells together?
tight junction
which cell junction anchors bundles of actin myofilaments between cells? which cell junction anchors intermediate filaments between cells?
adherens junction
which is the difference between a desmosome and a hemi-desmosome?
hemi-desmosome is desmosome sewed in half, hemi-desmosome anchors intermediate filaments to basal lamina while desmosome joins intermediate filaments to each other
which cell junction is involved in passage of ions or small molecules between adjacent cells?
gap junction
what are the 4 types of cell adhesion molecules discussed in lecture?
cadherin, selectin, integrin, immunoglobulin superfamily
which type of cell junctions contain cadherin proteins?
adherens junction
what do integrins bind to for cell-cell or cell-ECM interactions?
cell-cell bind integrin, cell-ECM bind collagen fibers or fibronectin
improper function of which cell adhesion molecule is involved in cancer and pemphigus?
cadherin- activity loss lead to epithelial tumors, pemphigus is autoimmune disrupting cadherin adhesion
improper function of which cell adhesion molecule is involved leukocyte adhesion deficiency?
integrins - they can't migrate, so they can't bind to anything
which type of cell adhesion molecule is overexpressed during asthma and rheumatoid arthritis?
ICAM-1 in asthma, integrin LFA-1/ICAM-2 in rheumatoid arthritis
what does selectin do?
allow cells to transiently interact with other cells bind specific sugars (sugar code)
how are cell adhesion molecules involved in the 4 steps of extravasion?
1- selectin on leukocyte binds to its ligand causing rolling of leukocyte 2- activation of integrin on leukocyte 3- integrin can bind to its ligand 4- diapedesis occurs- movement of leukocyte through endothelial layer
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