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182 Cards in this Set

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