ch 33

false

Acetylcholine is actively transported from the pre-synaptic membrane to the post-synaptic membrane

24Na+ and 16 K+

If a pump converts 8 ATP molecules to ADP and Pi, how many Na+ and K+ ions are transported across the membrane?

frequent pre-synaptic action potentials resulting in greater calcium influx and neurotransmitter release

Not every action potential is successfully transmitted by a postsynaptic neuron. Which of the following would increase the probability of the action potential transfer?

NA+ ions will bind to the pump but its conformation will not change, and movement of Na+ and K+ ions aganist the concentration gradient will stop.

You are conducting an experiment to test the role of ATP in NA+/K+ pump function. What do you predict wil happen when ATP is removed from the system?

oligodendrocyt

a support cell of the CNS that produces the myelin sheath

Schwann cells

a support cell of the peripheral nervous system that produces the myelin sheath

sensory neurons

afferent neurons that carry impulses from sensory receptors to the central nervous system

the resting membrane potential would not be reestablished

as maximum depolarization approaches, the sodium ion channels close. If you could experimentally prevent the ion channels from closing, what would be an expected response?

interneurons

association neurons that enable complex reflexes and higher functions such as learning and memory

utilizes only norepinephrine, innervates cardiac and smooth muscles and exocrine glands, can ecxcite or inhibit motor neurons, typically dual innervation of effector.

autonomic nervous system

Na+ moves into the cell, causing the intracellular space to become positive and the extracellular space to become negative

during an action potential charge, the relative charge across the membrane of an axon is reversed. Which ion makes the largest contribution to this change in potential and in what direction does the ion move?

Na+ moves into the cell, causing the intracellular space to become postive and extracellular space to become negative

during an action potential, the relative charge across the membranes of an axon is reversed. Which ion makes the largest contribution to this charge in potential, and in what direction does the ion move?

motor neurons

efferent neurons that carry impulses from the central nervous system to muscles and glands

chemical synapse: synaptic vesicles, neurotransmitters, voltage-gated calcium channels

identify the type of synapses found at the neuromuscular junction and the characteristics that define this type of synapse

dendrites, axons, muscle cells

in motor neurons, action potentials would result from neural signals received by the ___ which would travel down the ____ in order to stimulate ___

dendrites, axons, muscle cells

in motor neurons, action potentials would result from neural signals received by the _____ which would travel down ____ in order to stimulate ______

it will enable Na+ flux into the postsynaptic neuron in the absence of a presynaptic action potential

nicotine binds to aceytlcholine receptors at the synaptic cleft. Which is a likely effect of nicotine?

innervates skeletal muscle, always excites motor neurons, always single innervation of effector, utilizes acetylcholine

somatic nervous system

action potential stimulus, opening of sodium activation gates, movement of sodium ions into cell

steps involved in the depolarization of a neuron during an action potential in correct order

false (its active)

the action of the sodium-potassium pump is an example of passive transport

the sodium channels are closed, and the potassium channels are open

the action potential can move only in one direction because the recently depolarized are of the membrane is an absolute refractory period and cannot generate an action potential. What is occurring during the refractory period at the molecular level?

true

the initial charge outside the axon is positive

true

the initial charge outside the axon is positive.

potassium outside the cell, sodium inside the cell and ATP

the sodium potassium pump moves ions across a cellular membrane. What conditions need to be met for a single cycle of Na+/K+pump activity to occur?

There is a concentration gradient with more K+ in the intracellular space and more Na+ in the extracellular space

what conditions exist across a cell membrane due to action of the NA+ and K+ pump

the exterior of the cell has a net positive charge and the interior has a net negative charge

when the membrane of an axon is at resting potential, which of the following is true?

prior to the channels opening, a concentration gradient was established and now the ions move from high to low concentration

when the voltage-gated ion channels open, both sodium and potassium ions cross the membrane but in opposite directions? What is the ultimate cause of this occurrence?

More sodium ions diffuse into the cell than potassium ions diffuse out of it

why does depolarization occur?