Nervous system pt.3

Which of the following cause a postsynaptic transmission to stop?

-Diffusion of the neurotransmitter into the nearby extra-cellular fluid -Reuptake of the neurotransmitter by endocytosis -Degradation of the neurotransmitter in the synaptic cleft

relative refractory period

A new action potential is possible but only with a stronger than normal stimulus

Chemical Classes of Neurotransmitters

Acetylcholine, amines, amino acids, neuropeptides

Synapses

Area of communication where signals are transmitted between the two neurons that are communicating

Why is myelin important?

Assist in the regeneration of damaged fibers, speeds up signal conduction in the nerve fiber, it insulates the nerve fiber

involved in elevation of mood and the control of voluntary movement

Dopamine

True or false: receptors that bind the neurotransmitter at the postsynaptic cell membrane are voltage-gated.

False

Most common inhibitory neurotransmitter in the brain

GABA

In an action potential, which event directly follows repolarization?

Hyperpolarization of the membrane

Dopamine

Involved in elevation of mood and control of voluntary movement

Serotonin

Involved in sleepiness, alertness, thermoregulation, and mood

Acetylcholine

Located at the neuromuscular junctions; excites skeletal muscle, inhibits cardiac muscle

Why does depolarization occur?

More sodium ions diffuse into the cell, creating a positive charge.

absolute refractory period

No stimuli or any strength will generate a new action potential

ligand-gated channels

Respond to chemical stimuli

mechanically-gated channels

Respond to mechanical vibration, pressure, touch, and stretching stimuli

Norepinephrine

Sympathetic nervous system; dreaming, walking, and mood; excites cardiac muscle; can excite or inhibit smooth muscle and glands depending on location

The resting membrane potential is negative due to which of the following?

There are more negatively charged particles on the inside of the membrane than on the outside.

True or false: after the passage of the action potential, the sodium-potassium pump re-establishes the resting membrane potential.

True

True or false: if the postsynaptic membrane potential reaches threshold level, an action will be produced.

True

True or false: the area between the presynaptic nerve cell and the postsynaptic muscle cell is termed the synaptic cleft.

True

True or false: the sodium-potassium pump is involved in establishing the resting membrane potential.

True

excites skeletal muscle and inhibits cardiac muscle

acetylcholine

leak channels

alternate between open and closed randomly

When voltage-gated sodium channels are open, sodium flows _____________ the neuron making the inside of the cell more _______________.

into; positive

Which of the following will lower the speed of propagation of an action potential?

low temperature

GABA

most common inhibitory neurotransmitter

During the absolute refractory period which of the following is true?

no stimulus of any strength will trigger a new action potential

Involved in dreaming, waking, and mood. It also excites cardiac muscle

norepinephrine

Voltage-gated channels

respond to a direct changes in the membrane potential

involved in sleepiness, alertness, thermoregulation and mood

serotonin

Normally, sodium and potassium leakage channels differ because ___________________.

sodium ions diffuse through leakage channels into the cell, but potassium ions diffuse through leakage channels out of the cell

A synapse is:

space between adjacent neurons through which an impulse is transmitted

Which of the following factors will increase the speed of propagation?

temperature, myelination, axon diameter