Cell Physio (review test) Flashcards

1
Q

Shared characteristics of simple and facilitated diffusion of glucose

A

Both types occur down an electrochemical gradient

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2
Q

During upstoke of the nerve action potential

A

There is net inward current and the cell interior becomes less negative

  • Te inward current is carried by sodium
  • movement of positive charge into the cell
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3
Q

Solution A and B are separated by a semipermeable membrane that is permeable to K but not to Cl. Solution A is 100 mM KCL and solution B is 1 mM KCL. what will happen?

A

K will diffuse from solution A to solution B until a membrane potential evelops with solution A negative with respect to solution B

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4
Q

The correct temporal sequence for events a the neuromuscular junction is

A

Uptake of ca into the presynaptic terminal; release of ACh; deoplarization of the muscle end plate

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5
Q

Characteristic component shared by skeletal and smooth muscle

A

Elevation of intracellular calcium for excitation-contraction coupling

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6
Q

Repeated stimulation of a skeletal muscle fiber fauses a sustained contraction. Accumulation of which solute in intracellular fluid is responsible for tetanus

A

Calcium

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7
Q

Soluions A and B are separated by a membrane that is permeable to calcium and impermeable to Cl. Solution A contains 10 mM CaCl2 ans solution B contains 1 mM CaCl2. Assuming that 2.3 RT/F = 60mV, Ca will be at electrochemical equilibrium when

A

solution A is -30mV

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8
Q

A 42 y/o man with myasthenia gravis notes increased muscle strength when he is treated with AChE inhibitor. The basis for his improvement is increased

A

levels of ACh at the muscle end plate

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9
Q

In a hospital error, a 60 year old woman is infused with large volumes of a solution that causes lysis of her RBC. The solution was most likely

A

300mM urea

  • 150mM NaCL and 300mM mannitol are isotonic
  • 350mM mannitol and 150mM CaCl2 are hypertonic
  • 300 MM urea is hypotonicc
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10
Q

During a nerve action potential, a tmulus is deliered as indicated by the attow shown in the following figure. In response to the stimulus, a second action potential _____

A

will not occur

  • because the stimulus was delivered during the absolute refractory portion
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11
Q

Solution A and B are separated by a membrane that is permeable to urea. Solution A is 10MM urea, and soluton B is 5 mM urea. if the concentration of urea in solution A is doubled, the flux of urea across the membrane wall will

A

Triple

  • Flux is proportional to the concentration dfference across the membrane
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12
Q

A muscle cell has an intracellular [Na] od 14 mM and extracellular [Na] of 140 mM. Assuming that 2.3 RT/F = 60 mV, what would the membrane potential be if the muscle cell membrane were permeable to Na?

A

+60

  • Nernst equation
  • ENa = 2.3RT/zF Log Ce/Ci = 60 mV log 140/14 =60
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13
Q

at which labeled poiny on the action potential is K+ closest to electochemical equilibrium?

A

5

  • the hyperpolarizing afterpotential represents the period durimg K permeability is the highest and the membrane potential is clsoest to the K equilibrium potential
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14
Q

What process is responsible for the change in membrane potential that occurs between poin1 and point 3

A

Movement of na into the cell

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15
Q

What process is responsible for the change in membrane potential that occurs between point 3 and point 4

A

Movement of K out of the cell

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16
Q

The velocity of conduction of action potential along a nere will be increased by

A

myelinating the nerve

17
Q

Solutions A and B are separated by a semipermeable membrane. Solution A contains 1 mM sucrose and 1mM urea. Solution B contains 1 mM sucrose. the reflection coefficient for urea is zero. for sucrose is one. What will happen

A

Solution A is hyperosmotic with respect to solution B, and the solutions are isotonic

*

18
Q

transport of D and L glucose proceeds at the same rate down the elctrochemical gradient by which of the following processes

A

facilitate diffusion

19
Q

how can we double permeability of a solute in a lipid bilayer

A

doubling the oil/water partition coefficient of the solute

20
Q

A newly developed local anesthetic blocks sodium channels in nerves. Which of the following effects on the action potential would it be expected to produce?

A

Decrease the rate of rise of the upstroke of the action potential

21
Q

At the muscle end plate, ACh causes opening of the

A

Na and K channels and depolarization to a value halfway between sodium and K equilibrium potentials

22
Q

An inhibitory postsynaptic potential

A

hyperpolarizes the postynaptic membrane by opening Cl channels

23
Q

Which of the followinf would occur as a result of the inhibition of Na, K, ATPase?

A

increased intracellular calcium concentration

24
Q

Temporal sequence for excitation-contraction coupling in skeletal muscle?

A

Action potential in the muscle membrane; depolarization of the T tubules; release of calcium from the SR

25
Which of the following transport processes is involved if transport of glucose from the intestinal lumen into a small intestinal cell is inhibited by abolishing the usual Na gradient across the cell membrane?
Cotransport
26
In skeletal muscle, which of the following events occurs before depolarization of the T tubules in the mechanism of excitation contraction coupling?
Depolarization of the sarcolemma membrane
27
Which of the following is an inhibitory neurotransmitter in the CNS
GABA
28
ATP is used indirectly for which of the following processes
Absorption of glucose by intestinal epithelial cells
29
Causes rigor in the skeletal muscle?
A decrease in ATP level
30
Degeneration of dopaminergic neurons has been implicated in \_\_\_\_
Parkinson disease
31
Assuming complete dissociation of all solutes, which of the ff would be hyperosmotic to 1mM NaCl? * A. 1mM glucose * B. 1.5 mM glucose * C. 1 mM CaCl2 * D. 1 mM sucrose * E. 1mM KCl`
1mM CaCl2
32
A new drug is developed that blocks the transporter for H+ secretion in the gastric parietal cells. Which of the following transport processes is being inhibited?
Primary active transport
33
A 56 y/o woman with severe muscle weakness is hospitalized. The only abdnormality in her labratory values is an elevated serum K concentraion. the elevatedserum K causes muscle weakness because
Na channels are closed by depolarization
34
In contraction of GI smooth muscle, this event occurs after bindinf of calcium to calmodulin
Increased myosin-light-chain kinase
35
In an experimental preparation ofa nerve axon, membrane potential (Em), K equilibrium potential and K conductance can be measured. Which combination of values will create the largest outflow current flow
E