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Erstellt / Aktualisiert 09.02.2020 / 01.03.2020
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0 Exakte Antworten 0 Text Antworten 41 Multiple Choice Antworten
Fenster schliessen
  1. The direct impact of the electrogenic action of the sodium-potassium pump on the value of the resting membrane potential is:
a) Equal to zero as the resting potential is totally set by the passive transport

b) Crucial because electrogenicity of sodium-potassium pumps is the basic mechanism of the resting membrane potential

c) To contribute to approximately 5-10% of the value of the resting membrane potential

d) Not known

e) Is maximum at the equilibrium potential for chloride ions

Fenster schliessen
  1. When a negatively charged ion (anion) crosses the membrane from inside to outside of the membrane, the value of the membrane potential will:
a) Not be affected at all

b) Depolarize

c) Hyperpolarize

d) First hyperpolarize and then depolarize

e) First depolarize and then hyperpolarize

Fenster schliessen
  1. A robust excess of extracellular potassium concentration ([K]out) is known to lead to the cardiac arrest. Indicate most important cause of this effect:
a) A large increase in [K]out leads to membrane hyperpolarization

b) A large increase in [K]out leads to excessive activation of sodium potassium pumps

c) A large increase in [K]out leads to membrane depolarization which induces sodium channel inactivation and thereby membrane refraction

d) A large increase in [K]out causes depolarization and very frequent generation of action potentials which, in turn, dismantles ion concentration gradients

e) A large increase in [K]out causes structural instability of the ionic channels

Fenster schliessen
  1. Indicate the fastest mechanism of communication between two cells
a) Transmission in the chemical glutaminergic synapse

b) Transmission in the chemical GABAergic synapse

c) Release of modulators affecting the second messengers

d) Transmission in the electrical synapse

e) Covalent bonding with the extracellular matrix proteins

Fenster schliessen
  1. Nicotinic Acetylcholine receptors are:
a) anionoselective

b) cationoselective

c) selective for both anions and cations but to a different extent

d) inwardly rectifying

e) activated by intracellular nucleotides

Fenster schliessen
  1. Indicate the name of the disorder characterized by the following symptoms: muscle fatigability, deficit of acetylcholine receptors at the muscular endplates :
a) myothonia

b) fast channel myasthenic syndrom

c) myasthenia gravis

d) intoxication with strychnine

e) Alzheimer disease

Fenster schliessen
  1. In myothonia congenita the skeletal muscle fibers are:
a) Damaged because of the autoimmune action against the epitopes localized on their surface

b) Excessively excitable

c) Showing severe deficit in the excitability

d) Aberrantly innervated

e) Characterized by reduced number of acetylcholine receptors at the endplates

Fenster schliessen
  1. Indicate the type of channel responsible for a slow depolarization of the diastolic potential in the sino-atrial node
a) Voltage-gated sodium channel

b) Chloride channel

c) Inward rectifier potassium channel

d) Hyperpolarization-activated, cyclic nucleotide gated channel

e) Delayed rectifier potassium channels