BISC 306 Chapter 12- Nervous System

Use the Action Potential Transmission tab of the Membrane Potentials interactive to help you answer the question. What would happen to the action potential transmission if voltage‑gated sodium (Na+Na+) channels in the initial axon segment were abnormally far apart from one another?

The action potential would not propagate at all because the depolarization signal dissipates before the closest voltage‑gated Na+Na+ channels reach threshold.

Match each definition to the correct type of membrane potential. All of the definitions will be used. Resting membrane potential

The difference in charge across the membrane of an unstimulated cell

The Graded Potentials tab in the Membrane Potentials interactive allows you to alter a synapse, which affects the strength of the graded potentials that are generated. What actions can you take to maximize the graded potentials that are generated? click the Release sodium button add more excitatory ligand‑gated channels to the membrane click one Release neurotransmitter button multiple times add more sodium leak channels to the membrane

add more excitatory ligand‑gated channels to the membrane click one Release neurotransmitter button multiple times

Identify whether each term or phrase applies to an action potential, a graded potential, or both. Both (action and graded potential)

changes the cell membrane potential involves depolarization involved hyperpolarization

What is spatial summation?

combination of postsynaptic potentials due to the simultaneous stimulation of multiple synapses

Which of the statements are functions of neuroglia? electrically insulate axons of neurons remove cell waste and pathogens store and release neurotransmitters conduct afferent electrical signals

electrically insulate axons of neurons remove cell waste and pathogens

Use the Action Potential Propagation tab in the Membrane Potentials interactive to answer the question. Complete the statement to explain why an action potential will fail to propagate across a region of axon membrane where voltage‑gated sodium ion channels are not present. Without voltage‑gated sodium ion channels, localized repolarization to the resting potential does not take place. localized depolarization to threshold does not take place. receptors for excitatory neurotransmitters are not present. movement of sodium ions into the neuron is completely blocked.

localized depolarization to threshold does not take place.

Identify the autoimmune disorder associated with scarred and deteriorating myelin. multiple sclerosis muscular dystrophy type 1 diabetes epilepsy

multiple sclerosis

Match the descriptions to the types of neurons. Multipolar Bipolar Unipolar

multipolar neurons: three or more extensions come off of the cell body bipolar neurons: two extensions come off of the cell body unipolar neurons : one extension come off of the cell body

Which cells are part of nervous tissue? myofibrils mast cells neuroglia neurons

neurons neuroglia

In the Membrane Potentials interactive, excitatory neurotransmitter is represented by a blue square. What is the action of excitatory neurotransmitter?

opens a ligand‑gated sodium ion (Na+Na+) channel and allows Na+, Na+ to enter the postsynaptic neuron

What are the functions of the blood-brain barrier? prevents most of the toxins and microorganisms that might be circulating in the blood from entering the cerebrospinal fluid keeps the circulatory system's blood separate from the blood in the brain capillaries so nothing harmful can enter the brain slows blood flow through the brain's capillaries, allowing time for nutrient and waste exchange with the cerebrospinal fluid tightly controls the exchange of gases, nutrients, and waste between the blood and the brain's cerebrospinal fluid

prevents most of the toxins and microorganisms that might be circulating in the blood from entering the cerebrospinal fluid and tightly controls the exchange of gases, nutrients, and waste between the blood and the brain's cerebrospinal fluid

What is a membrane potential? the difference in charge across the cell membrane the difference in molecular concentrations across the cell membrane the number of molecules that cross the membrane in an hour the ability of a molecule to pass through a membrane

the difference in CHARGE across the cell membrane

Use the Action Potential tab of the Membrane Potentials interactive to help you answer the question. Depolarization of a region of a cell membrane occurs when the membrane potential becomes less negative than the resting value. Repolarization occurs when the membrane potential returns from the depolarized value to the resting value. Hyperpolarization occurs when the membrane potential becomes more negative than the resting value. Classify each type of channel according to the effect that opening the channel has on the membrane potential. Repolarization or hyperpolarization

voltage-gated potassium channels inhibitory ligand-gated channels

Use the Action Potential tab of the Membrane Potentials interactive to help you answer the question. Depolarization of a region of a cell membrane occurs when the membrane potential becomes less negative than the resting value. Repolarization occurs when the membrane potential returns from the depolarized value to the resting value. Hyperpolarization occurs when the membrane potential becomes more negative than the resting value. Classify each type of channel according to the effect that opening the channel has on the membrane potential. Depolarization

voltage-gated sodium channels excitatory ligand-gated channels

Place the steps for the mechanism of action of G protein‑linked receptors in order from the time a neurotransmitter binds the receptor to the generation of a physiological response. Neurotransmitter binds receptor to Physiological response

1) G protein is activated by GTP 2) The G protein binds to an effector protein 3) A second messenger is generated 4) Gene transcription is activated in the nucleus

Place the events of synaptic transmission in order. Action potential is generated in the presynaptic neuron. to Neurotransmitter effects are terminated.

1) The action potential arrives at the axon terminal 2) Voltage-gated Ca2+ channels int he axon terminal open, and Ca2+ flows inward down its concentration gradient 3) Cytosolic ca2+ stimulates synaptic vesicles to release neurotransmitter via exocytosis 4) Neurotransmitter diffuses across the synaptic cleft and binds to specific neurotransmitters receptors 5) Binding of neurotransmitter opens ion channels and causes a change in membrane potential.

Action potentials in neurons involve opening and closing of voltage‑gated Na+Na+ and K+K+ ion channels. Place the events of an action potential in order, starting and ending with a cell at its resting membrane potential. Resting state to Returning to resting state

1) a graded potential brings the membrane into threshold potential 2) fast Na+ and slow K + channels are activated 3) Na+ rushes into the cell causing membrane depolarization 4) K + channels fully open and Na+ channel inactivation Gates close 5) K + rushes out of the cell causing repolarization 6)K + channels close slowly resulting in hyperpolarization . Na+ channel gets reset

Which of the statements describes saltatory conduction? Conduction occurs exclusively at nodes of Ranvier. Voltage‑gated potassium channels open, depolarizing myelinated axons. Conduction occurs along unmyelinated axons, decreasing conduction velocity. Voltage‑gated sodium channels open, depolarizing unmyelinated axons.

Conduction occurs exclusively at nodes of Ranvier.

Identify each description as characteristic of the central nervous system (CNS) or the peripheral nervous system (PNS). Central nervous system

Consists of the brain and spinal cord. Integrates and interprets information.

Match each definition to the correct type of membrane potential. All of the definitions will be used. Graded Potential

Degree of depolarization is dependent strength of initial depolarizing stimulus

Match each definition to the correct type of membrane potential. All of the definitions will be used. Action Potential

Depolarization that occurs once the membrane potential meets the voltage threshold Degree of depolarization is independent of the strength of initial depolarizing stimulus

Classify each phrase as descriptive of either gray or white matter. White Matter

Myelinated Comprised of tracts of neuron axons Superficial layer of the spinal cord

Match each type of neuroglia to its function. Electrically insulateneurons Produce cerebrospinal fluid Phagocytize foreign matter Regulate chemical environment of neurons

Oligodendrocytes-Electrically insulateneurons Ependymal cell-Produce cerebrospinal fluid Microglial cells-Phagocytize foreign matter Astrocytes-Regulate chemical environment of neurons

Match each description to the appropriate refractory period. Relative Refractory Period

Potassium Channels begin to close Sodium channels finish resetting A stronger than normal stimulus is needed to initiate an action potential Hyperpolarization occurs

Identify the function of presynaptic and postsynaptic neurons at a given synapse.

Presynaptic neurons- transmit signals Postsynaptic neurons- receive signals

Identify each description as characteristic of the central nervous system (CNS) or the peripheral nervous system (PNS). Peripheral nervous system

Relays signals such as motor output. Includes motor neurons that innervate the leg muscles. Can receive information directly from the environment

Use the Action Potential tab in the Membrane Potentials Interactive to answer the question. How would an action potential be affected if there were no voltage‑gated potassium ion (K+)(K+) channels in the membrane of a neuron? Repolarization to the resting potential would take less time. Depolarization to the threshold point would take more time. Depolarization to the threshold point would take less time. Repolarization to the resting potential would take more time.

Repolarization to the resting potential would take more time.

Match each description to the appropriate refractory period. Absolute refractory period

Sodium influx occurs Depolarization occurs Another action potential cannot begin Potassium channels open Sodium Channels are inactive

Which statement describes how neurons use neurotransmitters to communicate with one another? Axons fuse with dendrites to produce a continuous cellular body that allows neurotransmitters to flow from one neuron to another. At synapses, axons release neurotransmitters that are recognized by proteins on dendrites. At synapses, dendrites release neurotransmitters that are recognized by proteins on axons. The axons of one neuron connect to the axons of another neuron to relay information through neurotransmitter release.

At synapses, axons release neurotransmitters that are recognized by proteins on dendrites.

Identify whether each term or phrase applies to an action potential, a graded potential, or both. A graded potential

Initiated by ligand-gated channels decremental potential

Identify whether each term or phrase applies to an action potential, a graded potential, or both. Action Potential

Initiated by voltage-gated potential All or none potential

Select the statement that describes signal transmission at an electrical synapse. Ions diffuse through gap junctions. Neurotransmitters diffuse through tight junctions. Neurotransmitters diffuse across a synaptic cleft. Ions diffuse through tight junctions.

Ions diffuse through gap junctions.

Which statement best describes the function of the nervous system? The nervous system signals muscle contraction but does not control gland secretion. The nervous system senses stimuli via efferent pathways and sends response signals. The nervous system consists of the brain and spinal cord, which are linked to each other by peripheral nerves. The nervous system senses stimuli, integrates information, and generates a response.

The nervous system senses stimuli, integrates information, and generates a response.

Classify each phrase as descriptive of either gray or white matter. Gray Matter

The primary location of synapse Unmyelinated constitutes the cerebral cortex

Select the statements that describe the distribution of ions across the membrane of a typical neuron. There is substantially less calcium outside the cell than inside the cell. There is substantially less chloride inside the cell than outside the cell. There is substantially less potassium inside the cell than outside the cell. There is substantially more sodium outside the cell than inside the cell.

There is substantially less chloride inside the cell than outside the cell. There is substantially more sodium outside the cell than inside the cell.