Anatomy Ch. 11 Nervous Tissue Questions

The part of the nervous system that controls smooth muscle, cardiac muscle and glands is the...

Autonomic nervous system, ANS. This contrasts with the somatic nervous system, which controls thought and movement. Divided into sympathetic and parasympathetic.

during repolarization of the plasma membrane,

K+ diffuses out of the cell.

the resting membrane potential results when the tendency for:

K+ to diffuse out of the cell is balanced by its attraction to opposite charges inside the cell

In a chemical synapse,

action potentials in the presynaptic terminal cause voltage-gated Ca+2 channels to open; neurotransmitters can cause ligand-gated Na+ channels to open; neurotransmitters can be broken down by enzymes; neurotransmitters can be taken up by the presynaptic terminal.

action potentials are conducted more rapidly:

along axons that have Nodes of Ranvier

leak ion channels

are responsible for the ion permeability of the resting plasma membrane

Neurotransmitter substances are stored in vesicles located in specialized portions of the:

axon

cells found in the choroid plexuses that secrete cerebrospinal fluid are:

ependymal cells

clusters of neuron cell bodies within the peripheral nervous system are:

ganglia

Decreasing extracellular concentration of K+ affects the resting membrane potential by causing:

hyperpolarization

If the permeability of the plasma membrane to K+ increases, the resting membrane potential difference:

increases. This is called hyperpolarization

summation

is caused by combining two or more graded potentials; occurs at the trigger zone of the postsynaptic neuron; results in an action potential if it reaches the threshold potential; can occur when two action potentials arrive in close succession at a single presynaptic terminal.

The absolute refractory period

limits how many action potentials can be produced during a given period of time; prevents an action potential from starting another action potential at the same point on the plasma membrane.

The *major* function of the sodium-potassium pump is to:

maintain the concentration gradients of Na+ and K+ across the plasma membrane

hyperpolarization

membrane potential becomes more negative

neuroglia that are phagocytic within the CNS are:

microglia

concerning concentration differences across the plasma membrane, there is:

more K+ inside the cell than outside, and more Na+ outside than inside

ion movement through the plasma membrane

movement of Na+ out of cell requires ATP, the diffusion of Na+ into the cell is inhibited when Ca+2 binds to proteins in the ion channels; specific ion channels regulate the diffusion of Na+ through the plasma membrane.

Motor neurons and interneurons are...

multipolar neurons

gray matter contains primarily:

neuron cell bodies

compared with the inside of the resting plasma membrane, the outside surface of the membrane is

positively charged

A subthreshold stimulus

produces a graded potential.

An inhibitory presynaptic neuron can affect a postsynaptic neuron by:

producing an IPSP in the postsynaptic neuron, hyperpolarizing the plasma membrane of the postsynaptic neuron; cause K+ to diffuse out the postsynaptic neuron; cause Cl- to diffuse into the postsynaptic neuron

graded potentials:

spread over the plasma membrane in decremental fashion; are not propagated for long distances; are confined to a small region of the plasma membrane; can summate

in convergent pathways,

the response of the postsynaptic neuron depends on the summation of EPSPs and IPSPs.

during depolarization of an action potential, the permeability of the membrane:

to Na+ is greatly increased