Bio 203 Module 4

gap junctions

transmembrane integral proteins form pores in cells and neighboring cells can send signals directly through the pores

contact signals

direct signals through neighboring cells, one has a ligand, one has a receptor

local signals

paracrine or autocrine

paracrine signaling

a cell releases its ligand into the ECF, another cell’s receptor accepts it (don’t have to be touching, but must be near eachother)

autocrine signaling

a cell releases a ligand and a receptor on that same cell accepts it

endocrine signaling

ligand in the blood stream, cells from almost anywhere in the body can accept the signal through its receptor

neurotransmitter

chemicals secreted by neurons that diffuse across a small gap to the target cell

neruohormone

chemicals released by neurons into the blood for action at distant cells

chemical synaptic transmission

when the electrical signal from the action potential in the presynaptic neuron’s axon is converted into a chemical signal at the synapse

presynaptic cell

the cell (always a neuron) that releases a chemical or electrical signal into the synapse, later to be accepted by the post synaptic cell.

postsynaptic cell

the cell (can be a neuron, Muscle cell (smooth, cardiac or skeletal), cardiac cell, conducting system cell, or an endocrine cell) that accepts the signal from the presynaptic cell across the synaptic cleft or direct contact

Synaptic bouton

end of the presynaptic cell (axon terminal) - contains synaptic vessicles

Synaptic vesicle

a small, membrane-bound organelle in the axon terminal of a neuron that stores neurotransmitters and releases them into the synaptic cleft to transmit signals to other cells

Synaptic cleft

the tiny gap separating the presynaptic (sending) and postsynaptic (receiving) neurons at a chemical synapse

axon terminal

the end of the axon — the part where the neuron passes its signal on to the next cell

ligand/first messenger

endogenous ligand

ligand from inside the body

exogenous ligand

ligand from outside the body that made its way in somehow

amplification

cell creates a large response from a small stimulus

lipopholic signals

signals that diffuse through the membrane and bind to cytosolic or nuclear receptors. Respond very slowly, but have long lasting responses

cytosolic receptor

receptor in the cytosol

nuclear receptor

receptor in the nucleus

hydrophilic signals

signals that cannot enter that cell, so they bind to cell membrane receptors. Respond really quickly, fast response

Cell membrane receptors

receptors on the cell membrane that can send a message into the cell

receptor channel

ligand binds to binding site on the channel, causing it to either open or close

G protein-coupled receptor

receptor is transmembrane and weaves in and out of membrane, also has a g protein integrated into the membrane. ligand binds to receptor, which activates the g-protein

receptor enzyme

when a ligand binds to the receptor, it activates the intracellular portion, which is the enzyme. The receptor itself is an enzyme.

integrin receptor

activates internal structures that can alter components of the cell

agonist

can activate the channel

antagonist

bind to the channel but doesn’t activate the receptor, blocking other ligands from binding