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1.) At the resting membrane potential, which statement is closest to being corre

ID: 3474336 • Letter: 1

Question

1.) At the resting membrane potential, which statement is closest to being correct:

     A.) Potassium ion channels are open, and there is a net loss of potassium ion due to

           diffusion down its concentration gradient from inside the cell to outside.

     B.) Potassium ion channels are open, and there is a net increase in intracellular

           potassium ion concentration because the ions are positively charged, and are

           attracted into the cell by the negative resting membrane potential.

     C.) The diffusion and electrostatic forces are equal and opposite, so potassium ion is

           in equilibrium (approximately).

     D.) Potassium ion channels are closed, so there is no ion movement across the cell

           membrane.

Activity 2

2.) In the patellar reflex the muscle spindle activates the ________ cell. It generates

      a(n) ________   _________ in response to the stimulus ________.

     A.) motor, action potential, pressure

     B.) sensory, receptor potential, stretch

     C.) motor, action potential, stretch

     D.) sensory, receptor potential, pressure

     E.) motor, action potential, contraction

Explanation / Answer

Answer 1: The correct anwer will be:

B.) Potassium ion channels are open, and there is a net increase in intracellular potassium ion concentration because the ions are positively charged, and are attracted into the cell by the negative resting membrane potential.

This is because at resting membrane potential, potassium ions are more permeable to the membrane than sodium ions, and thus they move inside the cell through voltage gated channel down their concentration gradient.

Answer 2:

The correct answer is :

D.) sensory, receptor potential, pressure

Patellar reflex is also called knee jerk reflex. as the name suggests, when pressure is applied on knee, or patellar bone, sensory nerves get activated in the spinal cord and sends the signal to the associated motor nerve directly. this is a monosynaptic relflex arc where sensoy nerves sends direct signal to motor neuron, without any interneuron in between. When receptor potential is generated in the motor neuron, muscles contract in reaction.