exam 1 reveiw Flashcards
axon hillock
the cone-shaped part of a neuron where the axon connects to the soma
synaptic vesicles
small, membrane-bound organelles found in the presynaptic terminal of neurons
. The osmolality and osmotic pressure of the plasma
is detected by osmoreceptors in the
hypothalamus of
the brain and maintained within a normal range by the
action of antidiuretic hormone (ADH) released from the
posterior pituitary.
If a poison such as cyanide stopped the production of ATP,
which of the following transport processes would cease?
The movement of Na+ out of a cell
Which of these statements comparing a 0.5 m NaCl solution
and a 1.0 m glucose solution is true?
a. They have the same osmolality.
b. They have the same osmotic pressure.
c. They are isotonic to each other.
Which of these statements regarding an increase in blood
osmolality is true?
a. It can occur as a result of dehydration
In hyperkalemia, the resting membrane potential
unaffected
na k pump
sodium out potassium in
Which of these statements about carrier-mediated facilitated
diffusion is true?
It is used for cellular uptake of blood glucose
The resting membrane potential of a neuron or muscle
cell is
. somewhat less negative than the potassium equilibrium
potential.
Suppose that gated ion channels for Na+ or Ca2+ opened
in the plasma membrane of a muscle cell. The membrane
potential of that cell would
a. move toward the equilibrium potential for that ion.
b. become less negative than the resting membrane
potential.
c. move farther away from the potassium equilibrium
potential.
. Which of the following questions regarding second
messengers is false?
a. They are needed to mediate the action of nonpolar
regulatory molecules
How will the signaling of a neuron be affected if the voltage-
gated sodium channels open at a more negative membrane
potential?
Neurons become hyperexcitable, firing APs more easily.
What effect will opening more potassium leak channels
have on the excitability of a neuron?
Hyperpolarization, less excitable
- A sensory, or afferent, neuron is
pseudounipolar
and conducts impulses from sensory receptors into
the CNS.
- A motor, or efferent, neuron is
multipolar and conducts
impulses from the CNS to effector organs.
- Interneurons are located entirely
within the CNS.
Depolarization of an axon is produced by
inward diffusion of Na+
Repolarization of an axon during an action potential is
produced by
c. outward diffusion of K+.
As the strength of a depolarizing stimulus to an axon is
increased,
the frequency with which action potentials are produced
increases
Which of these is not a characteristic of synaptic potentials?
They are all-or-none in amplitude.
A drug that inactivates acetylcholinesterase
increases the ability of ACh to stimulate muscle contraction.
Postsynaptic inhibition is produced by
depolarization of the postsynaptic membrane.
Hyperpolarization of the postsynaptic membrane in response
to glycine or GABA is produced by the opening of
Cl− channels
