Lecture 14 Flashcards
Epithelial, muscle, and nervous tissue cells characteristics
- little ECM
- intermediate filaments and cell-cell junctions provide strength
Connective tissue characteristics
- few cells
- have lots of extracellular matrix (ECM) that provides strength
Epithelial cells are organized into ___
sheets
the (epithelial) sheets can be rolled up into ____
tubes
tight junction
seals neighbouring cells together
adherens junction
joins actin bundle in one cell to a similar bundle in neighbouring cell
desmosome
joins intermediate filaments in one cell to those in a neighbour
gap junction
forms channels that allow small, intracellular, water-soluble molecs - including inorganic ions and metabolites to pass from cell to cell
hemidesmosome
anchors intermediate filaments in a cell to the basal lamina
plants only have ________ equivalent: plasmo_____
gap junction
desmata
Plasma membrane proteins anchor to what?
to cytoskeletal on the inside
Tight junctions form seals between cells which does what?
stops diffusion across the epithelial sheet
tight junctions allow ____ in the plasma membrane to diffue freely but NOT ______
lipids
membrane proteins
Epithelia are ________
functionally polarized
Tight junctions allow the ____ and _____ membranes to be different in function and composition
apical
basolateral
transcytosis
polarized transport of proteins from one side of the epithelium to the other
aherens junctions and desmosomes both use what to link the cytoskeleton of epithelial cells to their neighbours?
cadherins
hemidesmosomes link the cytoskeleton of epithelial cells to the _______ using ________
basal lamina
integrins
cadherin family
- transmembrane proteins - in the plasma membrane
- bind to an identical cadherin in the next cell
transmembrane proteins binding to identical cadherin in the next cell - interaction needs _____
calcium (Ca2+)
in adherens junctions, cadherins link to ______
actin filamets
adhesion belt
continuous band of adherens junctions
what link the cytoskeleton of epithelial cells to their neighbours? (and both use what?)
adherens junctions and desmosomes
they use cadherins
Desmosomes do what?
link intermediate filaments in each cell together across the epithelium
IFs provide protection against _____
stretching (epithelial and muscle cells)
desmosomes are abundant in what kind of tissue?
tissues under high shear stress - i.e. heart muscle
Desmosomes in adjacent muscle cells are linked to ______________
desmin intermediate filaments
Desmin is expressed in: (3)
- cardiac muscle
- skeletal muscle
- smooth mucle
desmin mutations cause: (2)
- muscular dystrophy
- cardiac myopathy
integrins in basal plasma membrane bind to:
laminin in the basal lamina
What difference are the membrane proteins in hemi-desmosomes and desmosomes?
integrins in hemi-desmosomes
cadherins in desmosomes
integrins in focal adhesions link to ________
actin filaments
integrin in hemi-desmosomes link to _________
keratin IFs
Epithelial cells express ______
E-cadherin
Muscle cells express ________
N-cadherin
What is the relation between cancer cells and cadherin expression?
cancer cells often no longer express the speciifc cadherins that would normally keep a cell in its correct place
85% of cancers start in ________ (And what are they called?)
epithelial tissues - these are carcinomas
Connexon channels allow ________ of inorganic ____ and small ___________
direct transfer
ions
water-soluble molecules (<1000 daltons)
Plasmodesmata
the plant equivalent of gap junctions
Large molecules can pass through _______ such as ___ and regulatory ____
plasmodesmata
proteins
mRNAs
