Multicellular organisms Flashcards
(36 cards)
tight junction
stitches the cell plasma membranes together. Like a coffee filter, makes an impermeable membrane to bigger solutes.
gap junction
like a hallway. lets materials pass through the hall between the two cells. can be used to couple neighboring cells, pass excitement–like in cardiac and smooth muscle
demosome
like a staple, a point connection between cells. anchoring two cells together, very strong because attaching cytoskeletons together. ex. heart and skin
hemidesmosome
not a cell-to-cell junction. attaches a cells cytoskeleton to the extracellular matrix
epithelial tissue
held together in continuous sheets–epithelium.
epithelium
continuous sheets of epithelial tissue. anchored to a thin mat of basement membrane
cutaneous membrane
covers body surfaces. stratified because it is acting as a protective barrier
serous membranes
cover organs and body cavities. for organs that move a lot, like the heart
mucous membranes
line the lumen of hollow organs that are open to the external environment. like the stomach and intestines
simple epithelial membranes
stratified for the transport of materials. epithelial cells have structural and functional polarity
basolateral side
where you have an underlying basement membrane. thin sheet of extracellular material that the cell is anchored to
apical membrane
lumenal membrane. facing the inside of the tube or hollow organ. inside of things=lumen
metabotropic receptors use second messenger pathways
Ca2+, cAMP, cGMP, IP3 and DAG
Ca2+
Ca2+–>calmodulum–>kinases
cGMP
guanylate cyclase–>cGMP–>protein kinase G
cAMP
adenlylate cyclase–>cAMP–>protein kinase A
IP3 and DAG
Phospholipase C–>PIP2–>IP3 and DAG–> Ca2+ release and activation of protein kinase C
benefits of metabotropic receptors
prolonged action, amplify primary message. Each G-protein can activate multiple adenylate cyclase=more cAMP= more kinase activation. Gives a much stronger response because multiple events are happening
Hydrophilic chemical messengers
can be synthesized in advance because they can just be stored in vesicles. no need to synthesize on demand. Release via exocytosis. Dissolve in the ECF, bind to transmembrane receptors on the surface of target cell.
Hydrophobic chemical messengers
signal cells must be synthesized on demand (can’t be packaged). released via simple diffusion directly across lipid bilayer. transported bound to carrier proteins within the bloodstream. Bind to intracellular receptors, molecules can just diffuse across the plasma membrane without any help
Intracellular receptors act as
transcription factors.
Activated intracellular receptors
hormone-receptor complex can translocate to the nucleus, make mRNA, translate the protein, then you have a physiological change
hydrophilic vs hydrophobic chemical messengers
hydrophilic faster, hydrophobic slower
fastest vs slowest chemical messenger pathway
ionotropic–>metabotropic–>hydrophillic–>hydrophobic
