A&P Ch. 10

Opioids relieve pain by blocking the release of

The afferent division of the PNS _____________.

Neuroglia perform all of these functions except __________.

The neuroglial cells that participate in maintaining the blood-brain barrier are the

The ________ nervous system is composed of the brain and spinal cord.

The ________ nervous system controls the skeletal muscles.

The efferent division of the peripheral nervous system innervates: skeletal muscle cells heart muscle cells glandular cells smooth muscle cells All of the answers are correct.

The axon hillock connects the axon with the __________.

Most CNS neurons fall into which structural category?

The most abundant class of neuron in the central nervous system is

Clusters of RER and free ribosomes in neurons are called

Branches that may occur along an axon are called

Axons terminate in a series of fine extensions known as

Neurons that have one axon and one dendrite, with the soma in between, are called

________ neurons are small and have no anatomical features that distinguish dendrites from axons.

Most CNS neurons lack centrioles. This observation explains: why CNS neurons cannot divide to regenerate damaged tissue. why CNS neurons grow such long axons. the ability of neurons to generate an action potential. the ability of neurons to produce a resting potential. the ability of neurons to communicate with each other.

The largest and most numerous of the glial cells in the central nervous system are the

Functions of astrocytes include all of the following, except: maintaining the blood-brain barrier. conducting action potentials. forming a three-dimensional framework for the CNS. guiding neuron development. responding to neural tissue damage.

The function of the astrocytes in the CNS includes which of the following? guiding neuron development adjusting the composition of the interstitial fluid maintaining the blood-brain barrier repairing damaged neural tissue All of the answers are correct.

________ line the brain ventricles and spinal canal.

The site of intercellular communication between a neuron and another cell is the

Sensory neurons of the PNS are

Small, wandering cells that engulf cell debris and pathogens in the CNS are called

The neurilemma of axons in the peripheral nervous system is formed by

Glial cells that surround the neurons in ganglia are

Many medications introduced into the bloodstream cannot directly affect the neurons of the CNS because: astrocytes form a capsule around neurons. the endothelium of CNS capillaries forms a blood-brain barrier. oligodendrocytes form a continuous myelin sheath around the axons. the neurolemma is impermeable to most molecules. ependymal cells restrict the flow of interstitial fluid between the capillaries and the neurons.

Extensive damage to oligodendrocytes in the CNS could result in: loss of the structural framework of the brain. loss of sensation and motor control. decreased production of cerebrospinal fluid. inability to produce scar tissue at the site of an injury. a breakdown of the blood-brain barrier.

Damage to ependymal cells would most likely affect the: transport of neurotransmitters within axons. formation of ganglia. repair of axons. formation of cerebrospinal fluid. formation of myelin sheaths.

In the peripheral nervous system, Schwann cells participate in the repair of damaged nerves by: forming a cellular cord that directs axonal regrowth. producing new axons. regenerating cell bodies for the neurons. clearing away cellular debris. producing more satellite cells that fuse to form new axons.

After a stroke, what type of glial cell accumulates within the affected brain region?

In a neuron, sodium and potassium concentrations are maintained by the sodium-potassium exchange pump such that __________. both sodium and potassium concentrations are higher outside the cell compared to inside. the sodium concentration is higher inside the cell than outside the cell and the potassium concentration is higher outside the cell than inside the cell. the concentration of sodium outside the cell is equal to the concentration of potassium inside the cell. the sodium concentration is higher outside the cell than inside the cell and the potassium concentration is higher inside the cell than outside the cell.

The sodium-potassium exchange pump transports potassium and sodium ions in which direction(s)? Sodium ions are transported into the cell. Potassium ions are transported out of the cell. Sodium ions are transported out of the cell. Potassium ions are transported into the cell. Sodium and potassium ions are both transported out of the cell. Sodium and potassium ions are both transported into the cell.

Leak channels allow the movement of potassium and sodium ions by what type of membrane transport?

The electrochemical gradient for potassium ions when the transmembrane potential is at the resting potential (-70 mV) is caused by what? a chemical gradient going out of the cell and an electrical gradient going into the cell chemical and electrical gradients both going into the cell chemical and electrical gradients both going out of the cell a chemical gradient going into the cell and an electrical gradient going out of the cell

Which type of ion channel is always open?

At the normal resting potential of a typical neuron, its sodium-potassium exchange pump transports: 3 intracellular sodium ions for 1 extracellular potassium ion. 3 extracellular sodium ions for 2 intracellular potassium ions. 2 intracellular sodium ions for 1 extracellular potassium ion. 1 intracellular sodium ion for 2 extracellular potassium ions. 3 intracellular sodium ions for 2 extracellular potassium ions.

Opening of sodium channels in the axon membrane causes

Voltage-gated channels are present: on the surface of dendrites. at the motor end plate. on the soma of neurons. along the perikaryon of neurons. in the membrane that covers axons.

The sodium-potassium ion exchange pump: must reestablish ion concentrations after each action potential. transports sodium ions into the cell during depolarization. depends on a hydrogen gradient for energy. moves sodium and potassium opposite to the direction of their electrochemical gradients. transports potassium ions out of the cell during repolarization.

________ open or close in response to binding specific molecules.

________ channels open or close in response to physical distortion of the membrane surface.

If the sodium-potassium pumps in the plasma membrane fail to function, all of the following occur, except: the neuron will slowly depolarize. the intracellular concentration of sodium ions will increase. the inside of the membrane will have a resting potential that is more positive than normal. the membrane will slowly lose its capacity to generate action potentials. the intracellular concentration of potassium ions will increase.

Graded potentials: produce an effect that spreads actively across the membrane surface. are often all-or-none. produce an effect that increases with distance from the point of stimulation. may be either a depolarization or a hyperpolarization. cause repolarization.

Voltage-gated sodium channels have both an activation gate and a(n) ________ gate.

If acetylcholine (ACh) causes inhibition of a postsynaptic neuron, to what type of membrane channel did the ACh bind? voltage-regulated sodium channel chemically-regulated sodium channel mechanically-regulated channel chemically-regulated potassium channel voltage-regulated calcium channel

If the axolemma becomes more permeable to potassium ion: sodium ions will enter the cell to replace the lost potassium ions a stronger stimulus will be required to cause an action potential the membrane will depolarize to +30 mV the inside of the membrane will have a positive charge the membrane will depolarize to threshold

What happens just after an axon is depolarized to threshold? Some sodium channels open. All sodium channels open. Some potassium channels open. All potassium channels open.

During repolarization of a neuron: both sodium and potassium ions move into the cell. potassium ions move into the cell. sodium ions move into the cell. sodium ions move out of the cell. potassium ions move out of the cell.

the depolarization necessary to cause an action potential is a

Rapid impulse conduction from "node" to "node" is called

A neuron that receives neurotransmitter from another neuron is called

Which type of synapse is most common in the nervous system?

The ion that triggers the release of acetylcholine into the synaptic cleft is

Cholinergic synapses release the neurotransmitter

If the chemically-gated sodium channels in the postsynaptic membrane were completely blocked,: the presynaptic neuron would release a different neurotransmitter. release of neurotransmitter would stop. smaller action potentials would result. the presynaptic membrane would be unable to reach threshold. synaptic transmission would fail.

Which of the following is not a possible drug effect on synaptic function? prevent neurotransmitter inactivation interfere with neurotransmitter reuptake block neurotransmitter binding to receptors change the type of receptor found in the postsynaptic membrane interfere with neurotransmitter synthesis

Which of the following is a recognized class of opioid neuromodulators? endorphins enkephalins endomorphins dynorphins All of the answers are correct.

Active neurons need ATP to support which of the following? the movement of materials to the soma by axoplasmic transport the recovery from action potentials the synthesis of neurotransmitter molecules the movement of materials from the soma by axoplasmic transport All of the answers are correct.

Presynaptic facilitation by serotonin is caused by: blockage of calcium channels in the presynaptic membrane. increased extracellular concentration of potassium ion. temporal summation. calcium channels in the presynaptic membrane remaining open longer. increased extracellular concentration of sodium ion.