Neurophysiology Flashcards
(109 cards)
Define glycocalyx.
is a glycoprotein and glycolipid pericellular matrix that surrounds the neuron, constituting a protective barrier
How is spontaneous movement of molecules and ions across a membrane possible?
passive transport down a concentration gradient
both in regard to particulate concentration and voltage - > electrochemical
Lipid bilayer is permeable to?
small polar molecules that are not ionized,
gases O2, CO2
water molecules,
steroid hormones
Lipid bilayer is not permeable to?
ions,
hydrophilic molecules and
macromolecules
Simple diffusion happens through what or where?
lipid bilayer or protein channels
specific water channels for the rapid water movement
Aquaporins
Describe facilitated diffusion
facilitated by carrier proteins
usually when molecules are too big to diffuse through the usual channels
Name the gross division for protein channels.
leak channels and gated channels
Name the channel type that requires a signal molecule for activation.
ligand-gated channels
triggered by ligands like acetylcholine, GABA, cAMP, ATP
Name the channel type that requires a mechanical signal.
stretch-activated channels
e.g. stretch receptors in muscles, sound receptors
Name the channel type that requires a change in electric-potential to react.
voltage-gated channels
e.g. Na-/K-channels of nerve and muscle cells
The difference between primary and secondary active transport?
In primary- the energy is required directly.
In secondary- the energy is derived secondarily from energy stored in the concentration gradients of ions.
Name a primary active transporter.
Na+/K+ ATPase transporter, or „pump“
Ca 2+ pump in skeletal muscles: elimination of Ca after contraction
Name the 2 types of secondary active transport.
shared carrier proteins - counter-transport, in which the two substrates cross the membrane in opposite directions (antiport)
and cotransport, in which they cross in the same direction (symport)
Name a secondary active transporter.
sodium-glucose linked transporter, SGLT in enterocytes
What type of transport is vesicular transport?
active transport
Give 2 examples of direct intercellular communication.
gap-junctions (common in smooth- and cardiac mm.)
nanotubes
Give 6 examples of indirect intercellular communication.
Cytokines Hormones Neurohormones Neurotransmitters Paracrines Pheromones
What are paracrines?
a form of cell signaling in which a cell produces a signal to induce changes in nearby cells
What are cytokines?
regulatory peptides such as interferon, interleukin, and growth factors, which are secreted by certain cells of the immune system and have an effect on other cells.
Normal membrane resting potential?
-70- 90 mV
some sources say -50- 75 mV
Define membrane potential.
Unequal distribution of ions on the outer and inner surface of plasma membrane and the difference in electric potential caused by this
Define action potential.
the rapid and propagating change of the resting membrane potential associated with the passage of an impulse along the membrane of a muscle or nerve cell.
what, in excitatory cells, opens in response to action potential
sodium- and potassium- gated ion channels