Chapter 12

The events of an EPSP in order

-The excitatory neurotransmitter binds to the chemically gated cation channel -More Na+ enters the postsynaptic cell then K+ leaves -inside of a cell becomes more positive -The local current Na+ becomes weaker as it moves towards the axon hillock

Membrane pumps require ________ energy

A lot of

Action potentials are always propagated along an axon at the same _______ but ________ can vary depending on the strength of the stimulus

Amplitude; frequency

The nerve impulse causes ________ in the number of the calcium ions that enter the synaptic knob

An increase

A substance synthesized at the cell body must undergo ____________ transport to reach the synaptic knobs

Anterograde

Which glial cell occupies the space of dying neurons?

Astrocytes

________ are star shaped

Astrocytes

A synapse is a junction _________.

Between a neuron and another cell

Many excitatory neurotransmitters cause the opening of channels that allow for the flow of ______.

Both Na+ and K+

Which are components of the central nervous system?

Brain and spinal cord

The presence of __________ ions causes the synaptic vesicles to bind to the membrane, allowing neurotransmitters to be released

Calcium

The total length of the axon is called the __________ segment

Conductive

The main activity of the _______ is the propagation of an action potential along the axolemma

Conductive segment

Another way for the neurotransmitter to be removed from the synaptic cleft by _________ where there is uptake by surrounding glial cells

Diffusion

Glial cells __________ transmit electrical impulses

Do not

Creating and transmitting ___________ currents is central to the function of neuron physiology

Electrical

Synapses are classified as __________.

Electrical and chemical synapses

A difference in the number of charged particles between two sides of the membrane forms a(n) ______________

Electrical gradient

What are characteristics of neurons?

Excitability, extreme longevity, conductivity, secretion, amitotic

True or false: a neuromodulator is another name for a neurotransmitter

False

A larger axon transmits an impulse _______ than a smaller axon

Faster

A potential there is a temporary change in membrane potential which lasts only as long as the stimulus that causes it in can vary in size is called a ________ potential.

Graded potential

The electrical gradient in a resting neuron is such that the ________ of the cell is negative relative to the _________.

Inside/outside

Neuronal pools are made of _________

Interneurons

The myelin sheath is made of a high percentage of __________.

Lipids

The brain interprets the increased frequency of nerve signals as a _________ stimulus

More intense

If a neuron has many dendrites and a single axon, it is called a(n) ______ neuron.

Multipolar

___________ neurons are most common

Multipolar

Which pumps can you find in the plasma membrane?

Na+, K+, Ca2+

Which of the following membrane transporters are present throughout the membrane of a neuron?

Na+/K+ Pumps, Potassium leak channels, sodium leak channels

A cablelike bundle of axons in the peripheral nervous system is called a _________.

Nerve

What is the primary tissue of the nervous system?

Nervous Tissue

The ability to alter the response of neurons to neurotransmitters is known as _______.

Neuromodulation

Neuronal pools are also called _________

Neuronal pathways and neuronal circuits

Nervous tissue is composed of glial cells and _________.

Neurons

_______________ are released from neurons in response to conductive activity

Neurotransmitters

A nerve is part of the ___________ nervous system

Peripheral

Na+ and K+ leak channels and Na+/K+ pumps on the neuron are responsible for establishing and maintaining the _______ membrane __________.

Resting membrane potential

The function of a neuron is dependent on __________.

Resting membrane potentials changing

Removal of neurotransmitters from the synaptic cleft

Reuptake

Glial cells are ________ than neurons

Smaller

A damaged axon within the PNS can regenerate if ___________.

Some neurilemma remains

"An action potential either happens or it doesn't." This statement could also be called _________.

The all-or-none law

The two factors that affect PNS regeneration are _________.

The amount of damage and the distance between the injury site and the effector organ

The myelin sheath covers ____________.

The axon

In retrograde transport, substances are moved _________ the cell body.

Toward

True or false: Graded potentials vary in size depending on the stimulus

True

The measure of the difference in electrical charge between two areas is called a _________.

Voltage

If a subthreshold value is reached on an axon membrane, an action potential __________.

Will not occur.