BIOL 2124 – Exam 3

What is the anatomical division of the nervous system located within the cranial and vertebral cavities, namely the brain and spinal cord? [Reading 15]

Central nervous system (CNS)

What is the anatomical division of the nervous system that is largely outside the cranial and vertebral cavities? [Reading 15]

Peripheral nervous system (PNS)

What type of neural tissue cells are responsible for the maintenance of the tissue, and largely responsible for supporting neurons? [Reading 15]

Glial cells

What type of neural tissue cells are primarily responsible for generating and propagating electrical signals in, within, and out of the nervous system? [Reading 15]

Neuron

What is the portion of the neuron that contains a nucleus and is considered the cell body? [Reading 15]

Soma

What is the portion of the neuron that is an extension of the cell body? [Reading 15]

Process

What is the single process of the neuron that carries an electrical signal (action potential) away from the cell body toward the target cell? [Reading 15]

Axon

What is one of many branchlike processes that extends from the neuron cell body and functions as a contact for incoming signals (synapses) from other neurons or sensory cells? [Reading 15]

Dendrite

What is the term for regions of the nervous system containing cell bodies of neurons with few or no myelinated axons? [Reading 15]

Gray matter

What is the term for regions of the nervous system containing mostly myelinated axons, making the tissue appear white because of the high lipid content of myelin? [Reading 15]

White matter

What is the term for the lipid-rich insulating substance surrounding the axons of many neurons, allowing for faster transmission of electrical signals? [Reading 15]

Myelin

What is the term for a localized collection of neuron cell bodies in the CNS? [Reading 15]

Nucleus

What is the term for a cluster of neuron cell bodies in the PNS? [Reading 15]

Ganglion

What is the term for a bundle of axons, or fibers, in the central nervous system (CNS) having the same function and point of origin? [Reading 15]

Tract

What is the term for a cord-like bundle of axons, or fibers, in the peripheral nervous system that transmits sensory input and response output to and from the central nervous system? [Reading 15]

Nerve

What is the nervous system function that receives information from the environment and translates it into the electrical signals of nervous tissue? [Reading 15]

Sensation

What is the nervous system function that causes a target tissue (muscle or gland) to produce an event as a consequence to stimuli? [Reading 15]

Response

What is the nervous system function that combines sensory perceptions and higher cognitive functions (memories, learning, emotion, etc.) to produce a response? [Reading 15]

Integration

What is the term for an event in the external or internal environment that registers as activity in a sensory neuron? [Reading 15]

Stimulus

What type of response is governed by the somatic nervous system? [Reading 15]

Voluntary

What type of response is governed by the automatic nervous system? [Reading 15]

Involuntary

Which functional division of the nervous system is concerned with conscious perception, voluntary movement, and skeletal muscle reflexes? [Reading 15]

Somatic nervous system (SNS)

Which functional division of the nervous system is responsible for homeostatic reflexes that coordinate control of cardiac and smooth muscle, as well as glandular tissue? [Reading 15]

Autonomic nervous system (ANS)

What is the neural tissue associated with the digestive system that is responsible for nervous control through autonomic connections? [Reading 15]

Enteric nervous system (ENS)

What is the narrow junction across which a chemical signal passes from one neuron to the next, initiating a new electrical signal in the target cell? [Reading 15]

Synapse

What is the tapering of the neuron cell body that gives rise to the axon? [Reading 15]

Axon hillock

What is the cytoplasm of the axon, which is different in composition than the cytoplasm of the neuronal cell body? [Reading 15]

Axoplasm

What is the term for the first part of the axon as it emerges from the axon hillock, where electrical signals known as action potentials are generated? [Reading 15]

Initial segment

What is the insulating substance made from glial cells that wraps axons? [Reading 15]

Myelin

What is the gap between two myelinated regions of an axon, allowing for strengthening of the electrical signal as it propagates down the axon? [Reading 15]

Node of Ranvier

What is the single stretch of the axon insulated by myelin and bounded by nodes of Ranvier at either end (except for the first, which is after the initial segment, and the last, which is followed by the axon terminal? [Reading 15]

Axon segment

What is the end of the axon, where there are usually several branches extending toward the target cell? [Reading 15]

Axon terminal

Which shape of a neuron has only one process that includes both the axon and dendrite? [Reading 15]

Unipolar

True unipolar cells are only found in invertebrate animals. What is a more appropriate term for the shape of neuron found in humans? [Reading 15]

Pseudo-unipolar

What cells have the following characteristics?

• Dendrites receive sensory information, sometimes directly from the stimulus itself

• Exclusively sensory

• Cell bodies are always found in ganglia

• Axons project from the dendrite endings, pass the cell body, and into the central nervous system

[Reading 15]

Unipolar cells

Which shape of a neuron with two processes extending from the neuron cell body (the axon and one dendrite)? [Reading 15]

Bipolar

Which cell is uncommon and found mainly in the olfactory epithelium (where smell stimuli is sensed), and as part of the retina? [Reading 15]

Bipolar cells

What is the shape of a neuron that has multiple processes (the axon and two or more dendrites)? [Reading 15]

Multipolar

What is the glial cell type of the central nervous system (CNS) that provides support for neurons and maintains the blood-brain barrier? [Reading 15]

Astrocytes

Which glial cell type supports neurons by maintaining the concentration of chemicals in the extracellular space, removing excess signaling molecules, reacting to tissue damage, and contributing to the blood-brain barrier? [Reading 15]

Astrocytes

What is the physiological barrier between the circulatory system and the central nervous system (CNS) that establishes a restriction on what substances can cross from circulating blood into the central nervous system? [Reading 15]

Blood-brain barrier

What is the glial cell type in the central nervous system (CNS) that provides the myelin insulation for axons in tracts? [Reading 15]

Oligodendrocytes

What is the glial cell type in the central nervous system (CNS) that serves as the resident component of the immune system? [Reading 15]

Microglia

What is the glial cell type of the central nervous system (CNS) that filters blood to make cerebrospinal fluid (CSF)? [Reading 15]

Ependymal cells

What is the circulatory medium within the central nervous system (CNS) that is produced by ependymal cells in the choroid plexus filtering the blood? [Reading 15]

Cerebrospinal fluid (CFS)

What is one of the four central cavities within the brain, lined with ependymal cells, where cerebrospinal fluid (CSF) is produced and circulates? [Reading 15]

Ventricle

What is the specialized structure in the ventricles where ependymal cells come in contact with blood vessels and filter and absorb components of the blood to produce cerebrospinal fluid? [Reading 15]

Choroid plexus

What is the glial cell type in the peripheral nervous system (PNS) that provides support for neurons in the ganglia? [Reading 15]

Satellite cells

What is the glial cell type in the peripheral nervous system (PNS) that provides the myelin insulation for axons in nerves? [Reading 15]

Schwann cells

What are the glial cell types of the central nervous system? [Reading 15]

Astrocyte, oligodendrocyte, microglia, and ependymal cells

What are the glial cell types of the peripheral nervous system? [Reading 15]

Satellite cells and Schwann cells

What is the lipid-rich layer of insulation that surrounds an axon, formed by oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system, and facilitates the transmission of electrical signals? [Reading 15]

Myelin sheath

Where are the nucleus and cytoplasm of the Schwann cell located on the edge of? [Reading 15]

Myelin sheath

What type of sensory receptor is capable of transducing temperature stimuli into neuron action potentials? [Reading 15]

Thermoreceptor

What is the change in the membrane potential that varies in size, depending on the size of the stimulus that elicits it? [Reading 15]

Graded potential

What is the term for the membrane potential at which an action potential is initiated? [Reading 15]

Threshold

What is accepted as threshold? [Reading 15]

-55 mV

What is the change in voltage of a cell membrane in response to a stimulus that results in transmission of an electrical signal, unique to neurons and muscle fibers? [Reading 15]

Action potential

What is the movement of an action potential along the length of an axon, from the axon hillock to the axon terminals? [Reading 15]

Propagation

What is the chemical signal that is released from the synaptic end bulb of a neuron to cause a change in the target cell? [Reading 15]

Neurotransmitter

What is the region of the central nervous system (CNS) in the brain that acts as a relay for sensory pathways or information? [Reading 15]

Thalamus

What is the outermost layer of gray matter in the brain, where conscious perception takes place? [Reading 15]

Cerebral cortex

Where does the thalamus send sensory information to? [Reading 15]

Cerebral cortex

What is the first neuron in the motor command pathway with its cell body in the cerebral cortex that synapses on the lower motor neuron in the spinal cord? [Reading 15]

Upper motor neuron

What is the region of the cerebral cortex responsible for generating motor commands, where the upper motor neuron cell body is located? [Reading 15]

Precentral gyrus of the frontal cortex

What is the second neuron in the motor command pathway that is directly connected to the skeletal muscle? [Reading 15]

Lower motor neuron

What is the cell membrane that regulates the movement of ions so that an electrical signal can be generated? [Reading 16]

Excitable membrane

Are charged particles hydrophobic or hydrophilic? [Reading 16]

Hydrophilic

Is the phospholipid bilayer hydrophobic or hydrophilic? [Reading 16]

Hydrophobic

What proteins do charged particles utilize to get through the phospholipid bilayer? [Reading 16]

Channel proteins

Is the concentration of Na+ higher inside or outside the cell? [Reading 16]

Outside

Is the concentration of K+ higher inside or outside the cell? [Reading 16]

Inside

In which direction does the sodium/potassium pump move sodium ions (Na+)? [Reading 16]

Outside

In which direction does the sodium/potassium pump move sodium ions (K+)? [Reading 16]

Inside

What are pores that allow specific charged particles to cross the membrane in response to an existing gradient? [Reading 16]

Ion channels

Which channel opens because a signaling molecule binds to the extracellular region of the channel? [Reading 16]

Ligand-gated channel

Which channel opens because of a physical distortion of the cell membrane? [Reading 16]

Mechanically-gated channel

Which channel responds to changes in the electrical properties of the membrane in which it is embedded, or membrane potentials? [Reading 16]

Voltage-gated channel

Which channel is randomly gated, with an intrinsic rate of switching between the open and closed states, contributing to the resting transmembrane voltage of the excitable membrane? [Reading 16]

Leak channel

What is the term for the distribution of charge across the cell membrane, based on the charges of ions? [Reading 16]

Membrane potential

When a channel opens for Na+ in the membrane, the concentration gradient will cause ions to rush into the cell. Will this cause the membrane potential to become more positive or negative? [Reading 16]

Positive

What is the resting membrane potential? [Reading 16]

-70 mV

What is the term for the change in the cell membrane potential from rest toward zero? [Reading 16]

Depolarization

As the membrane potential reaches +30mV, other voltage-gated channels open in the membrane specific to the potassium ion. K+ begins to leave the cell. Will this cause the membrane potential to become more positive or negative? [Reading 16]

Negative

What is the term for the return of the membrane potential to its normally negative voltage at the end of the action potential? [Reading 16]

Repolarization

What is the term for the brief dip in the membrane potential below the normal resting voltage as a result of the K+ channels’ delay in closing? [Reading 16]

Hyperpolarization

What causes a ligand-gated Na+ channel to open? [Reading 16]

Neurotransmitter

What causes a mechanically-gated Na+ channel to open? [Reading 16]

Physical stimulus

The ligand-gated Na+ channels depolarize the cell membrane from -70 mV to -55 mV, at which point which channels open? [Reading 16]

Votage-gated channels

What is the part of the voltage-gated Na+ channel that opens when the membrane voltage reaches threshold? [Reading 16]

Activation gate

What is the part of the voltage-gated Na+ channel that closes when the membrane potential reaches +30 mV? [Reading 16]

Inactivation gate

What is the time after the initiation of an action potential when another action potential cannot be generated under normal circumstances? [Reading 16]

Refractory period

What is the time when another action potential cannot be generated because the voltage-gated Na+ channel is inactivated? [Reading 16]

Absolute refractory period

What is the time during the refractory period when a new action potential can only be initiated by a stronger stimulus than the current action potential because the voltage-gated K+ channels are not closed? [Reading 16]

Relative refractory period

What is the slow propagation of an action potential along an unmyelinated axon owing to voltage-gated Na+ channels located along the entire length of the cell membrane? [Reading 16]

Continuous conduction

What is the quick propagation of an action potential along a myelinated axon owing to voltage-gated Na+ channels being present only at the nodes of Ranvier? [Reading 16]

Saltatory conduction

What is the graded potential from the dendrites of a unipolar cell which generates the action potential in the initial segment of that cell’s axon? [Reading 17]

Generator potential

What is the graded potential in a specialized sensory cell that directly causes the release of neurotransmitters at synapses with sensory neurons, without an intervening action potential? [Reading 17]

Receptor potential

What is the graded potential in the postsynaptic membrane caused by the binding of a neurotransmitter to protein receptors, located in the dendrites and cell bodies of a neuron that synapse with other cells? [Reading 17]

Postsynaptic potential (PSP)

What is the graded potential in the postsynaptic membrane that is the result of depolarization, causes the membrane potential to move toward threshold, and makes an action potential more likely to occur? [Reading 17]

Excitatory postsynaptic potential (EPSP)