A&P Exam 2

Practice Questions & General terms

Which of the following is NOT a function of nervous tissue?A. Rapid communication

Hormone secretion into blood

The part of the neuron that receives incoming signals is the

Dendrite

Which glial cell forms the myelin sheath in the CNS?

Oligodendrocyte

The Nissl bodies in neurons are composed of?

Rough ER and ribosomes

Which type of neuron has one axon and one dendrite?

Bipolar

The blood–brain barrier is primarily maintained by?

Astrocytes

Which glial cell lines the ventricles and produces CSF?

Ependymal cell

Saltatory conduction occurs in?

Myelinated axons

The resting membrane potential of a typical neuron is approximately?

–70 mV

Which ion is most responsible for depolarization during an action potential?

Na⁺

Which ion is most responsible for repolarization?

K⁺ efflux

The refractory period ensures?

Action potentials travel in one direction

Which of the following is a major inhibitory neurotransmitter in the CNS?

GABA

Which structure releases neurotransmitters

Synaptic knob

Which glial cell removes pathogens and debris in the CNS?

Microglia

Nodes of Ranvier are important because they?

Allow ion exchange for action potentials

A neuron that conducts impulses from receptors to the CNS is a?

Sensory neuron

Which of the following best describes graded potentials?

Decrease with distance

Myelin in the PNS is produced by?

Schwann cells

Which neurotransmitter is released at neuromuscular junctions?

Acetylcholine

Which of the following increases conduction velocity?

Presence of myelin

A synapse between a neuron and a muscle fiber is called a?

Neuromuscular junction

Which glial cell surrounds neuron cell bodies in the PNS?

Satellite cells

Which of the following is TRUE about action potentials?

 They are all-or-none

Which neurotransmitter is associated with reward pathways?

Dopamine

Which structure initiates the action potential?

Axon hillock

Which of the following is characteristic of unipolar neurons?

Found in sensory ganglia

Which glial cell helps regulate extracellular ion concentrations?

Astrocytes

Which of the following occurs at chemical synapses?

Neurotransmitter release

Which of the following increases the likelihood of generating an action

potential?

EPSPs

The resting membrane potential of most neurons is closest to?

 −70 mV

The primary ion responsible for establishing the resting membrane potential is?

K⁺

Which protein maintains the resting membrane potential by pumping ions

against their gradients?

Na⁺/K⁺ ATPase pump

During depolarization, the membrane potential becomes?

More positive

Threshold for triggering an action potential is typically?

−55 mV

Voltage-gated Na⁺ channels open in response to?

Depolarization

The rapid rise in membrane potential during an action potential is due to?

Na⁺ influx

Repolarization is primarily caused by?

Opening of K⁺ channels

The period during which a neuron cannot generate another action potential,

regardless of stimulus strength, is the?

Absolute refractory period

 Hyperpolarization occurs because?

K⁺ channels remain open too long

Which ion has the greatest influence on membrane potential due to its high

permeability at rest?

K⁺

The Nernst equation calculates?

Equilibrium potential for an ion

Saltatory conduction occurs in

 Myelinated axons

Myelin increases conduction velocity by

Increasing membrane resistance

Nodes of Ranvier contain high densities of?

Voltage-gated ion channels

Graded potentials differ from action potentials because graded potentials?

Can summate

Temporal summation occurs when?

One synapse stimulates repeatedly in rapid succession

Spatial summation occurs when?

Multiple synapses fire at the same time

Which event immediately follows Na⁺ channel inactivation?

Repolarization

 The relative refractory period occurs because

K⁺ channels are still open

 Action potentials propagate in one direction because

Na⁺ channels are inactivated behind the AP

Which ion movement is responsible for returning the membrane to resting

potential after hyperpolarization?

Na⁺/K⁺ pump activity

The amplitude of an action potential is determined by?

All-or-none principle

Which of the following increases conduction velocity?

Larger axon diameter

An inhibitory graded potential typically involves?

K⁺ efflux or Cl⁻ influx

 Depolarization to threshold is most likely when?

EPSPs summate

Which channel type is responsible for neurotransmitter release at the axon

terminal?

Voltage-gated Ca²⁺ channels

 The rising phase of the action potential ends when?

Na⁺ channels inactivate

Which of the following best describes graded potentials?

Decremental

Action potentials are generated at the axon hillock because?

It contains the highest density of voltage-gated Na⁺ channels

Which glial cell forms the myelin sheath in the CNS?

Oligodendrocytes

Which glial cell forms the myelin sheath in the PNS?

Schwann cells

Which glial cell regulates the blood–brain barrier?

Astrocytes

Which glial cell acts as the CNS immune cell?

Microglia

Which glial cell lines the ventricles?

Ependymal cells

Which glial cell surrounds neuronal cell bodies in ganglia?

Satellite cells

Which glial cell helps maintain extracellular ion balance in the CNS?

Astrocytes

Which glial cell is responsible for producing CSF?

Ependymal cells

Which glial cell provides metabolic support to neurons?

Astrocytes

Which term describes neurons with a single process that splits into peripheral and central branches?

Unipolar neurons

Which neuron type has two distinct processes: one dendrite and one axon?

Bipolar neurons

Which neuron type is most common in the CNS?

Multipolar neurons

Which term describes neurons that cannot be structurally distinguished between axons and dendrites?

Anaxonic neurons

Which functional class carries impulses toward the CNS?

Sensory neurons

Which functional class carries impulses away from the CNS?

Motor neurons

Which functional class connects sensory and motor neurons?

Interneurons

Which structural class is typical of olfactory receptor neurons?

Bipolar neurons

Which structural class is typical of dorsal root ganglion neurons?

Unipolar neurons

Which neuron type has multiple dendrites and a single axon?

Multipolar neurons

Which structure initiates action potentials?

Axon hillock

Which part receives most synaptic input?

Dendrites

Which structure releases neurotransmitters?

Axon terminal

Which structure speeds conduction of action potential?

Myelin

Which gap allows saltatory conduction?

Nodes of Ranvier

Which structure carries impulses away from the soma?

Axon

Which term describes a small, localized change in membrane voltage?

Graded Potential

Which term refers to the minimum membrane voltage needed to trigger an action potential?

Threshold Potential

Which term describes the rapid rise in membrane potential during an action

potential?

Depolarization

Which term describes the return of membrane potential toward resting levels after depolarization?

Repolarization

Which term describes the phase where the membrane becomes more negative than the resting potential?

Hyperpolarization

Which term describes the additive effect of multiple graded potentials?

Summation

Which term describes the period when a neuron cannot generate another action potential?

Refractory period (Absolute)

Which term describes action potential movement along an axon?

Propagation

Which term describes the jump-like conduction along myelinated axons?

Saltatory

 Which term describes the membrane potential of a neuron at rest? 

RMP (Resting Membrane Potential)

Which protein primarily composes thick filaments in muscle fibers?

Myosin

The functional unit of a muscle fiber is the?

Sarcomere

Which structure stores calcium ions in skeletal muscle cells?

Sarcoplasmic reticulum

The A band of a sarcomere contains?

Both actin and myosin

Which region shortens during muscle contraction?

 I band