Anatomy and Physiology Chapter 12

Which of the choices below reflects the correct order of changes in membrane potential as a hypothetical neuron goes from: rest; to the peak of the action potential; through the refractory period; and then returns to rest? 0 mV; +40 mV; +10 mV; 0 mV -65 mV; +45 mV; +100 mV; -65 mV -65 mV; +45 mV; -70 mV; -65 mV +40 mV; -40 mV; -50 mV; +40 mV

-65 mV; +45 mV; -70 mV; -65 mV

Over time, long-term depression can lead to which of the following changes? A signaling cascade leading to the endocytosis of AMPA receptors from the postsynaptic synapse A signaling cascade leading to the insertion of AMPA receptors in the presynaptic synapse A signaling cascade leading to the endocytosis of AMPA receptors from the presynaptic synapse A signaling cascade leading to the insertion of AMPA receptors in the postsynaptic synapse

A signaling cascade leading to the endocytosis of AMPA receptors from the postsynaptic synapse

What is the most abundant type of glial cell in the central nervous system? Satellite cells Astrocytes Oligodendrocytes Neurons

Astrocytes

cerebral capillaries of the blood-brain barrier? Neurons Pericytes Astrocytes Endothelial cells

Astrocytes

Where is the action potential generated in a neuron? Axon terminal Synaptic cleft Axon hillock Cell body

Axon hillock

Where is a neurotransmitter located before it is released to another cell? Axon terminal Soma Nodes of Ranvier Dendrites

Axon terminal

Action potentials can: Travel directly across the synaptic cleft Be caused by neurotransmitter binding Trigger neurotransmitter release Both B and C

Both B and C

Which of the following is the first step in the transmission of signals at a chemical synapse? Calcium channels open Neurotransmitters bind to postsynaptic receptors Calcium comes into the presynaptic cell Neurotransmitters are released

Calcium channels open

One well-studied mechanism of LTD depends on the concentration of what ion? Magnesium ions flowing into the postsynaptic neuron Magnesium ions flowing into the presynaptic neuron Calcium ions flowing into the presynaptic neuron Calcium ions flowing into the postsynaptic neuron

Calcium ions flowing into the postsynaptic neuron

Which of the following structures are often highly branching and receive signals? Nodes of Ranvier Synapses Dendrites Axons

Dendrites

Synaptic vesicles ________ the membrane of the __________, releasing neurotransmitter. Fuse to; axon terminal Diffuse through; postsynaptic cell Are transported out of; presynaptic cell Diffuse through; axon terminal

Fuse to; axon terminal

Which of the following describes electrical synapses, but not chemical synapses? The action potential in the presynaptic cell results in the opening of calcium channels Gap junctions open to send the electrical signal directly to the next neuron Receptors bind to neurotransmitters Neurotransmitters are released from the presynaptic cell

Gap junctions open to send the electrical signal directly to the next neuron

Why is the sodium-potassium pump important to the action potential? It causes there to be more sodium outside and more potassium inside of cells, which drives the flow of ions during the action potential. It causes there to be more sodium inside and more potassium outside of cells, which drives the flow of ions during the action potential. It equalizes the concentrations of sodium and potassium on both sides of the membrane, readying the neuron to fire an action potential. It excites the Nodes of Ranvier, so that the action potential can be regenerated down the axon.

It causes there to be more sodium outside and more potassium inside of cells, which drives the flow of ions during the action potential.

When voltage-gated sodium channels open in a neuron, what happens to the membrane potential as a result? It depolarizes rapidly. It hyperpolarizes to threshold. It depolarizes to threshold. It hyperpolarizes rapidly.

It depolarizes rapidly.

How does the sodium-potassium pump contribute to the resting membrane potential? It establishes a gradient of potassium across the membrane; potassium ions then flow down the gradient, creating a charge across the membrane. It opens potassium and sodium channels, allowing these ions to equilibrate across the membrane until the resting potential is reached. It uses up energy that would otherwise be used to fire action potentials, maintaining the resting potential. It pushes potassium into the cell, creating a charge across the membrane.

It establishes a gradient of potassium across the membrane; potassium ions then flow down the gradient, creating a charge across the membrane.

N-Methyl-D-aspartate, or NMDA receptors, are usually inactivated by what ion? Potassium ions Magnesium ions Sodium ions Calcium ions

Magnesium ions

Which of the following statements is false? Oligodendrocytes phagocytize pathogens and debris. Schwann cells and oligodendrocytes perform similar functions. Glial cells outnumber neurons. Glial cells play a role in synaptic pruning.

Oligodendrocytes phagocytize pathogens and debris.

Why can potassium ions easily diffuse across the membrane of neurons at rest, unlike most other ions? -Potassium channels are the main type of ion channels that are open at rest, and most ions can't diffuse directly across cell membranes. -The potassium pump selectively diffuses it out. -The resting membrane potential selectively pushes potassium out. -Potassium is the only ion that has a concentration gradient across the membrane.

Potassium channels are the main type of ion channels that are open at rest, and most ions can't diffuse directly across cell membranes.

Which type of molecule is most likely to pass through the blood-brain barrier via simple diffusion? Incorrect answer: All of the above Small, lipid-soluble molecules Water-soluble molecules Large, lipid-insoluble molecules

Small, lipid-soluble molecules

Which of the following does not happen after a neurotransmitter binds to a postsynaptic receptor? The neurotransmitter may enter the postsynaptic cell. The neurotransmitter may be degraded The neurotransmitter may diffuse away from the synapse. The neurotransmitter may be recycled.

The neurotransmitter may enter the postsynaptic cell.

Which is true about how messages are typically transmitted at chemical synapses? The signaling molecule jumps electrically from the presynaptic cell to the postsynaptic cell. The signaling molecule is secreted directly into the postsynaptic cell from the presynaptic cell. The signaling molecule binds to receptors on the surface of the postsynaptic cell. Synaptic vesicles travel from the presynaptic cell to the postsynaptic cell.

The signaling molecule binds to receptors on the surface of the postsynaptic cell.

The peripheral nervous system does not transmit sensory information. Neurons are the only type of cell in the nervous system. The spinal cord is part of the central nervous system. The central nervous system only consists of the brain.

The spinal cord is part of the central nervous system.

Which of the following is usually true about a neuron at rest? There is relatively more negative charge outside the cell membrane. The resting potential is about +70 mV. There is relatively more negative charge inside the cell membrane. There is no difference in charge across the cell membrane.

There is relatively more negative charge inside the cell membrane.

Which of the following statements are false? The BBB protects the brain from toxins. Weak junctions between endothelial cells of the BBB allow passage of substances from the circulation to the brain. Dysregulation of BBB function is implicated in several neurologic diseases, including multiple sclerosis. Pericytes are located outside of the capillary walls and closely associate with endothelial cells.

Weak junctions between endothelial cells of the BBB allow passage of substances from the circulation to the brain.

Signals become intracellular when the ligand binds to the receptor and activates: protein kinase A phosphatases adenylate cyclase a second messenger

a second messenger

The nervous system regulates: voluntary movements all of the above unconscious processes reflexes

all of the above

Arginine vasopressin is: an endocrine signal all the above a hormone released by the pituitary gland

all the above

Arginine vasopressin is: released by the pituitary gland an endocrine signal a hormone all the above

all the above

Cyclic AMP (cAMP): is produced by adenylate cyclase is a second messenger all the above activates PKA

all the above

Endocrine signaling occurs between: Correct answer: endocrine cells and cells found in other organs remote body parts only cells in the circulatory system two adjacent cells

endocrine cells and cells found in other organs

Endocrine signaling occurs between: Incorrect answer: two adjacent cells only cells in the circulatory system endocrine cells and cells found in other organs remote body parts

endocrine cells and cells found in other organs

Endocrine signaling uses what to communicate? ion exchanges neurotransmitters large molecule carbohydrates hormones

hormones

Endocrine signaling uses what to communicate? neurotransmitters hormones large molecule carbohydrates ion exchanges

hormones

With LTP, a signaling cascade leads to the insertion of AMPA receptors in the postsynaptic synapse, resulting in: increased postsynaptic glutamate influx decreased postsynaptic calcium influx decreased presynaptic glutamate influx increased postsynaptic calcium influx

increased postsynaptic calcium influx

The intracellular signaling cascades amplify the external signal when: less second messenger is activated than the ligand binding to the receptor after PKA phosphorylates CREB the ligand repeatedly binds the receptor more second messenger is activated than the ligand binding to the receptor

more second messenger is activated than the ligand binding to the receptor

Bundles of axons are called: glia none of the above nerves ganglia

nerves

Long-term potentiation is a process by which: synapses between pre- and post-synaptic neurons are strengthened due to repeated postsynaptic action potential. synapses between pre- and post-synaptic neurons are strengthened due to repeated presynaptic action potentials. synapses between pre- and post-synaptic neurons are weakened due to repeated postsynaptic action potential. synapses between pre- and post-synaptic neurons are weakened due to repeated presynaptic action potentials.

synapses between pre- and post-synaptic neurons are strengthened due to repeated presynaptic action potentials.

synapses between pre- and post-synaptic neurons are not affected, but axonal transmission is slowed. synapses between pre- and post-synaptic neurons are strengthened. none of the above synapses between pre- and post-synaptic neurons are weakened.

synapses between pre- and post-synaptic neurons are weakened.