Cell Physiology Flashcards
Permits current flow and electrical coupling between myocardial cells?
Gap junctions
Galactose is a competitive inhibitor of glucose transport. In what carrier mediated characteristic?
Competition
D-glucose is transported by facilitated diffusion , but the L-isomer is not.
In what carrier mediated characteristic?
Steriospecificity
Glucose transport in muscle and adipose cells in downhill and is carrier mediated. In what type of transport?
Facilitated diffusion
Na-K-2Cl in the renal thick ascending limb.
In what type of transport?
Co-transport / Symport
Na-Glucose cotransport:
Glucose is transported ____________,
Na is transported ______________.
Uphill, Downhill
(glUcose: Uphill)
Na-Ca counter-transport : Energy is derived from the _______.
Derived from the downhill movement of Na.
What is the osmolarity of a 1M NaCl solution?
2 Osm/L
Osmolarity= g x C
Osmolarity = 2 Osm / mol x 1M
Osmolarity = 2 Osm/L
At resting potential, the activation gates are ______ and thus the Na channels are ________?
Closed, Closed
True or False.
The activation gate of Na channel in nerve is opened by depolarization.
True
True or False.
The inactivation gate of Na channel in nerve is closed by depolarization.
True
True or False.
If either the activation or inactivation on the gate of Na channel in nerve is closed, the channel is closed and impermeable to Na.
True
Small channels lined with negatively charged groups will be selective for _______ and exclude ___________.
Small Cation, Large solutes and anions.
(Small Negative Cat)
Nerve membrane at rest is far more permeable to what solute?
K+ than Na+
What is the resting membrane potential of the nerve?
-70mv
What is the calculated K equilibrium potential ?
-85mV
What is the calculated Na equilibrium potential ?
+65 mV
Characteristic shared by simple and facilitated diffusion of glucose?
Occurs down an electrochemical gradient
Occurs during the upstroke of the nerve action potential?
Net inward current and the cell interior becomes less negative.
True or False.
Depolarization is caused by an inward current and in most muscle types, inward current is carried by Na+
True
Correct temporal sequence for events at the neuromuscular junction ? (3)
- Uptake of Ca into the presynaptic terminal
- Release of Acetylcholine
- Depolarization of the muscle end plate
Characteristic shared by skeletal muscle and smooth muscle?
Elevation of intracellular Ca for excitation - contraction coupling.
Solute responsible dor tetanus?
Calcium
A 42 yo Male with myasthenia gravis improves with acetylcholinesterase inhibitor. Basis of improvement?
Levels of ACh at the muscle end plates increases.
Effect of myelinating the nerve in the conduction velocity of action potentials?
Increased conduction velocity.
Transport of D and L glucose proceeds at the same rate down an electrochemical gradient. In what transport process?
Simple Diffusion
According to BRS, only two types of transport occur downhill - simple diffusion & facilitated. If there is no stereospecificity for the D- or L-isomer ,o nce can conclude that the transport is not a carrier mediated. In real life, this is through simple diffusion.
Doubles the permeability of a solute in a lipid bilayer?
Doubling the oil/ water partition coefficient of the solute
Effect of local anesthetic blocking Na+ channels in nerves?
Decrease the rate of rise of the upstroke of the action potential.
Channels opened by acetylcholine at the muscle end-plate ?
Na and K channels and depolarization to a value halfway between the Na and K equilibrium potentials.
Defines inhibitory postsynaptic potential?
Hyper-polarizes the postsynaptic membrane by opening a-channels.
Result of the inhibition of Na K ATPase.
Effect on intracellular calcium?
Increased intracellular Ca concentration
Abolishing the Na gradient across the cell membrane will affect which glucose intestinal transport process?
Cotransport
Occurs before depolarization of the T tubules in the skeletal muscle?
Depolarization of the sarcolemmal membrane.
Inhibitory neurotransmitter in the CNS?
GABA
B- Brain
What process that Indirectly use ATP in the intestinal cells?
Absorption of glucose by intestinal epithelial cells, occurs by secondary active transport.
Causes rigor in skeletal muscles?
A decrease in ATP level
Disease with degeneration of dopaminergic neurons?
Parkinson disease
Transport process blocked by the drug class PPI.
Primary Active Transport