Exam 4: Principles of Neural and Hormonal Communication

When EPSPs occurring simultaneously from two different presynaptic inputs add together or sum to bring the postsynaptic cell to threshold, it is called ____________________.

The Na? and K? channels that open and close during an action potential are voltage-gated channels.

Which of the following is not a graded potential?

The neuronal relationship where a single presynaptic cell branches to terminate on many other cells is called ____________________.

MATCHING Indicate the direction that the force in question tends to move the involved ion under the stated conditions by writing the appropriate letter in the blank, using the following answer code: -electrical gradient for K⁺ at the peak of an action potential

Neurotransmitters are small, ____________________-acting molecules.

Which class(s) of hormone(s) is not stored in the secretory cell after being synthesized?

Indicate whether the characteristics below apply to the endocrine system or the nervous system by writing the appropriate letter in the blank using the following answer code: -Speed of response is long (minutes to days or longer).

Select the incorrect statement about the postreceptor events of hydrophilic hormones.

Indicate the solubility characteristics of each of the classes of hormones by writing the appropriate letter in the blank using the following answer code: -steroids

Spatial summation occurs in a postsynaptic neuron

The specific site upon which a hormone exerts its effect is referred to as a(n) ____________________ cell.

Only hormones that are not bound to plasma proteins are biologically active.

Temporal summation takes place when

Which of the following statements concerning the absolute refractory period is inaccurate?

____________________ is the most common second messenger.

The accompanying figure relates to neurotransmitter secretion. Match the steps highlighted in the figure (steps 1-5) with the statements using the letter key below. -Neurotransmitter binds to receptors

A high percentage of sodium and potassium ions move during each action potential.

Which of the following statements concerning propagation of action potentials is incorrect?

The following question refers to comparative concentrations, permeabilities, and potentials under various circumstances. Indicate the relationship between the two items listed in each situation by filling the appropriate letter in the blank using the following answer code: -A. permeability of a resting nerve cell membrane to K⁺ B. permeability of a resting nerve cell membrane to Na⁺