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182 Cards in this Set
- Front
- Back
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What is tissue?
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A functional collection of cells with a specific role.
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What is a distinguishing feature of epithelium?
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They are close together.
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Is connective tissue closely or widely apposed?
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It is more widely separated.
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What are two types of epithelium?
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Surface and glandular
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Where is glandular eptihelium?
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Glands and ducts.
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What does surface epithelia cover?
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It covers the external surface of our body. It lines the body cavities, tubes, and blood vessels of heart.
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What does surface epithelium rest on?
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The basement membrane.
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What is the basement membrane?
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A layer of noncellular material
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When one draws the epithelium, it is necessary to draw the basement membrane?
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Yes.
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What are the two surfaces of epithelium called?
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Apical surface and basal surface.
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Is epithelium vascular?
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No, it is avascular.
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Where does epithelium get its nutrients if its avascular?
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It gets them from the capillaries in the underlying connective tissue.
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The number of cells is simple or ______?
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Stratified.
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The shape of cells is squamous, _____, or _____?
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Cuboidal or columnar.
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What determines how epithelia are classified?
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The shape and number.
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What do they look like in squamous cells?
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Fried eggs.
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Cuboidal epithelium look like what?
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They have equal length and height.
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Where is the nuclei in cuboidal epithelium located?
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They are located in the center.
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The position and shape of the nucleus is then an important characteristic to determine what?
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The cell shape.
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What are columnar cells?
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They are tall cells.
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Where are columnar nuclei found?
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They are found at the base of the cell most likely rather than the apex.
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Where are squamous cells principally?
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They are in the blood vessels of the heart.
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What is it called rather than epithelium when lining the blood vessels of the heart?
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It is called endothelium.
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What is the mesothelium?
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This is the lining of most body cavities.
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Where are cuboidal cells found?
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They are found in kidney tubules.
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What do goblet cells do?
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They secrete mucus
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What is the primary function of simple stratified epithelium?
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It's primary function is to provide protection.
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What are the two kinds of simple stratified epithelium?
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They have non-keratinized and keratinized.
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Is non-keratinized more wet or dry than keratinized?
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More wet, due to various secretions.
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What is the oral and esophagus region covered by?
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Non-keratinized squamous stratified.
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Describe the surface cells in keratinized squamous stratified?
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They are dead, flattened cells.
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How do they have so much keratin, it looks like so much?
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It's because they've lost their nuclei, and have just keratin mainly.
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What gets sloughed off in our skin?
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The apical surface of flattened, keratinized squamous stratified.
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Cuboidal and columnar are two more types of what?
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Stratified epithelium.
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Are cuboidal and columnar one or two cell layers thick?
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Two cell layers thick.
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Where are cuboidal and columnar found?
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They are found in ducts of certain glands.
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What is pseudo-stratified epithelium?
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It means it looks stratified, but it isn't.
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Why are they actually not stratified if they look it then?
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Because all the cells rest on the basement membrane.
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What is an example of a pseudo-stratified cell?
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An example are the ciliated cells interspersed with goblet cells in the trachea and bronchi.
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Where is the second type of pseudo-stratified found?
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They are found in the male reproductive tract, like in the ductus epididymous
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What is transition epithelia?
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It is stratified, usually with 4 - 6 layers, and it is found in the lining of the urinary bladder and urethras.
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What is transition epithelia specialized to do?
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It is specialized to be stretched.
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What is the principle feature of transitional epithelium?
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It is large and dome shaped.
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How many nuclei do transitional epithelium have?
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One or sometimes two.
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What is transitional epithelium full of?
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Actin filaments.
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When the bladder distends, the epithelium stretches out, and it looks like there are fewer cell layers, and these surface cells become what?
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Flattened.
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When distended, what does transitional epithelium look like then?
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Squamous epithelium.
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So how many simple?
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3 simple
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How many stratified?
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3 stratified
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What is the term used by us to describe basement membrane?
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Basal lamina.
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How many layers does the basal lamina have?
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It has two layers.
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What is the dense layer of basal lamina called?
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It is called lamina densa.
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What is the light layer called?
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Lamina rara.
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What is the reticular lamina?
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It is underneath the basal lamina and is comprised of collagen fibers mostly.
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What molecules make up the basal lamina?
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Collagen type IV, heparin sulfate proteoglycan, and laminin
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What does collagen type IV mostly make?
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It mostly makes fibrils, but there is a meshwork, like a screen door.
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What physical property does this afford for the lamina densa?
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It gives the lamina desna its strength.
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What is another major molecular constituent of collagen type IV?
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Proteoglycans, which are large molecules with a protein core, with then sugar groups attached to the protein core.
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What does heparin sulfate proteoglycan do?
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It is largely responsible for the permeability of the basal lamina.
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So, the basal lamina is permeable?
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Yes, it has to be able to pass nutrients released from capillaries to the connective tissue.
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What is laminin?
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It is a glycoprotein.
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What does laminin do?
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It has different domains, which bind to collagen type IV and to integrin receptors in the epithelial cell membrane.
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So what does it do then?
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It gives epithelial cells the ability to attach to the basal lamina.
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What is a junctional complex?
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There are 3 junctions here in characteristic sequence, from surface to basal cell, with most at the apex.
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What is the first one, nearest the surface?
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The zonula occludens, or tight junction.
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What is right below the zonula occludens, and what is this structure also known as?
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It is the macula adherens, which is also known as the desmosome.
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What does the zonula occludens do?
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It occludes, or blocks the space between adjacent cells.
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What is the protein that is localized in the zonula occludens called, that joins cells together?
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Claudin membrane protein.
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The apical surface is considered to be anything above or below the zonula occludens?
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Anything above it.
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What is the junction below the zonula occludens called?
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The zonula adherens.
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What does the zonula adherens do?
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It is a continuous belt of adjacent cells, and it has the function of attaching cells together.
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What does the zonula adherens have attached to it and embedded into the cytoplasm?
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Actin filaments.
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What is E-cadherin?
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It is a member of the cadherin family of adhesion molecules, and these are called adherins because they are calcium dependent adhesion molecules.
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What does E-cadherin bind to?
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Other E-cadherins from the adjacent epithelial cell.
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How does actin come into play here?
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Actin is what attaches eventually to the E-cadherin and binds it to the cell with serious strength.
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What is the macula adherens?
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It is the strongest form of attachment.
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What causes cells to be joined together so tightly in macula adherens?
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Desmocollins and desmogleins.
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What are desmocollins and desmogleins?
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They are members of the adherin family but are given special names.
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What is the analogy for them?
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They are like spot welding cells together.
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Let's say they're spot welded, how do they embed into the epithelia?
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They insert proteins in the cytoplasmic plaque, and then the intermediate filaments insert into the cytoplasmic plaque.
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So to summarize, zonula occludens does what?
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Blocks of space between cells
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What let's things through?
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Adherin junctions
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What is key of epithelia being able to serve their function?
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Desmosomes or the macula adherens.
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What is an early sign of cancer?
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When tumors grow, they split from one another. These junctions dissolve in one early step in metastasis.
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What is the functional complex near the apical surface, which serves a new function to let certain things through?
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Gap junctions.
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What is the role of gap junctions?
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They allow adjacent cells in the epithelium to communicate with one another.
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How do cells communicate through gap junctions?
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There are membrane proteins in the region of these junctions.
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What is the name of what these proteins form?
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They form a connexon.
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What can pass through them?
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Ions, inorganic ions, and small molecules.
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Can glucose pass from cell to cell?
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Yes.
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What else can they share via this?
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Potassium, sodium.
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What does this make cells?
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It makes them electrically coupled.
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Do connexons have any strength?
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No, very little. It's like putting on straw into another and letter fluid pass through.
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What are microvilli?
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They are fingerlike projections on the apical surface of many cells, predominantly lining the small intestine.
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What do striations in a light micrograph of the small intestine show?
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They are actually the microvilii.
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Do kidney cells have microvilli?
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Yes.
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What are kidney cells with microvilii called as a result?
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The brush border.
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What does having microvilli do physiologically?
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It allows for more surface area.
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Intestinal epithelium is what cell type?
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Columnar
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What are the long things in the core of the filaments that run the length of the microvilii?
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They are actin filaments.
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What is the terminal web?
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It is a region underlying the microvilli with numerous kinds of filaments.
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What does this web span?
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The apical cytoplasm, which allows connections between actin filaments and microvillus to occur and anchor one another.
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Are these actin cores rigid or loose?
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They are very rigid, and dont allow much bending.
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In EM's there is a fuzzy surface associated with the extracellular space further out than even the microvilli, so what is that?
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It refers to the sugar coating of the membrane.
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What are stereocilia?
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They are very long microvilli.
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What do they share with microvilli?
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They share an internal core of actin filaments.
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How much larger are cilia than microvilli?
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They are about 3 times longer.
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In an EM graphic view of 2 cilia, you see microtubules running the length of the cilia, and at the base of the cilia are whats called _____?
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A basal body.
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What is the internal structure of cilia?
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An internal core of 9 doublet microtubules arrounded around 2 center microtubules, yielding the 9+2 arrangement.
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What is this core called?
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This is called the axoneme.
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What does the basal body consist of?
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9 triplet microtubules.
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What is the structure of the basal body the same as?
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The structure of the centriole
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Centriole become what?
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They migrate to the apical surface and become procentrioles and then a basal body, which initiates the polymerization of microtubules to make axoneme.
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What is an important function of cilia?
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They bend
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Where are cilia prominant?
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The respiratory tract
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What allows them to move?
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There are two little arms projecting off each doublet.
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What are these arms made of?
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Dynein.
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What does dynein do?
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It attaches one doublet together, like how myosin acts in muscle contraction.
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Does water regulate pH?
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Yes.
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What does CO2 come from?
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Partly from oxidation of food.
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What are three buffer systems in the body?
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Bicarbonate, phosphate and hemoglobin.
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Are the kidneys involved in a buffer system, and if yes, what do they excrete as a result?
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Ammonium ions and phosphate.
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Is water polar?
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Yes, very.
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Is water a good solvent?
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Yes, it is.
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What is water a good solvent for?
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It is a good solvent for polar and hydrophilic molecules.
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Does water have a high heat of evaporation?
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Yes.
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Does water have a high dielectric constant?
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Yes it does.
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What type of structure does water have? Tetrahedral
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So oxygen is positive or negative? Negative
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Which makes the hydrogens in water what?
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Partially positive.
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What is hydrogen bonding in water?
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It is due to the partial charges of hydrogen and oxygen in water that allows it to create electrostatic interactions between other waters (and other molecules that will interact)
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Does hydrogen bonding do anything important?
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This is what gives water its unique properties.
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In ice, is the water closer or farther than in liquid water?
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They are farther apart in ice, and closer in water. This is what gives them a crystalline structure.
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Does this impart a change in physical property for water as an ice?
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Yes, this is why water as ice is less dense.
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Are hydrogen bonds longer than covalent bonds?
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Yes they are.
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Do you find hydrogen bonds in nucleic acids?
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Yes you do. The two helices are held together by hydrogen bonds.
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Do you find them in sugars?
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Yes.
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Why do you find them in sugars?
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Sugars have lots of hydroxyl groups, and they interact with water, and water will help break them up.
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Is cellulose hydrogen bonded together?
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Yes
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Does this impart any physical properties to them?
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Yes, this is why they have such a great deal of strength
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What do hydrophobic forces do to water, like if you immersed water with a hydrocarbon, what happens to water?
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The hydrocarbons can't hydrogen bond, so it disrupts the structure of water.
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What is this referred to as?
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Hydrophobic interactions.
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What are amphipathic molecules?
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They are mixtures of hydrophobic and hydrophilic structures
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What is an example of an amphipathic molecule?
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Detergent or fatty acids.
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What is the structure of a detergent?
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Long hydrocarbon chains and a long polar end
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The polar end in detergent may be what?
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It may be a sulfate or have an amino end.
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How are bases held together in nucleic acids?
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They are held together by hydrophobic forces.
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Are lipids soluble in water?
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No.
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What do lipids form when needing to be transported through water then?
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Lipoproteins
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What are lipoproteins?
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They are structured with lipids in the middle and proteins on the exterior. Hydrophobic in the middle, and hydrophilic on the outside.
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What is the force between two two things electrostatically based upon?
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It is based upon the charge, the distance between them, and the factor called the dielectric constant.
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Does a vacuum or water have a higher dielectric constant?
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Water has a dielectric constant of 80. A vacuum is 1.
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What are VdW's forces?
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They are forces that occur as molecules get closer together.
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Are VdW's strong or weak?
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Weak
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Then what's the point?
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Lots of them put together makes a sizeable difference, rather than having none at all.
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What is an acid?
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Proton donor.
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What is a base?
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Proton acceptor
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HA is what?
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Acid
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A:- is what?
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Base
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What does pK equal?
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It equals the negative log of K
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Is the dissociation constant a constant?
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No, it depends on whether or not the pK is 6.8 or 7.2, and it changes as a result.
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What is an easy way to remember how kD relates to strength of an acid?
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The greater the kD, the greater the degree of dissociation, and the stronger the acid.
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What is a buffered solution?
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One that resists changes in pH.
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What is our bodies pH?
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7.4
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What does a buffer contain?
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An acid and it's conjugate base.
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Is a pure acid or salt a buffer, ever?
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No.
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When you first change pH in a titration curve, will it change quickly or slowly?
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Quickly
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When does it slow down?
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When it reaches the buffered region.
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The steepest part of the curve correlates to what in a titration curve?
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It correlates to the half-titration point.
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What is the relationship to pH and pKa?
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pH equals pKa
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What is a polyprotic acid?
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It's an acid that can donate more than one proton.
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If something has a pK of about 3, what is it probably?
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It probably is a carboxyl group.
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What is the isoelectric point?
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It's the point where it wont move an electric charge.
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What is a phosphate buffer?
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It's a very common buffer, with 3 dissociable groups.
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What are it's 3 pKa's?
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2, 6.8, and 11.8
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Is phosphate in the urine?
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Yes
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What does the HH equation allow you to do?
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Describe a buffer system, and it relates the pH of the buffer to the pK of the buffer.
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How is the pH of a buffer related to the pK of a buffer?
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They are determined by the ratio of conjugate base to the acid.
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What is the law of electroneutrality?
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It says if you have a solution, it has to be electrically neutral.
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When you have 1 millimole of acid, and you convert that acid to conjugate base, how much conjugate base do you have?
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1 millimole.
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How many acidic groups are in an amino acid?
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At least 2 acidic groups.
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What is the pK of an amino group?
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9-10
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So, if you have an acid, and are titrating it, with an amino group and a carboxyl group, what will pop off first?
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The carboxyl group, because it has a lower pK.
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