Activity 12 - Neural Histology

Which term refers to the gaps between segments of myelin along an axon? •Initial segments •Internodes •Synapses •Nodes of Ranvier

Nodes of Ranvier

Cells called ____ form myelin sheaths in the peripheral nervous system, while cells called ____ form myelin sheaths in the central nervous system. •oligodendrocytes; microglia •Schwann cells; oligodendrocytes •Astrocytes; microglia •ependymal cells; astrocytes

Schwann cells; oligodendrocytes

The sensory & motor divisions of the peripheral nervous system are further split into which two subdivisions? •Proximal and distal •Somatic and visceral •Autonomic and voluntary •Spinal cord and brain

Somatic & visceral

Which term applies to the small swellings at the distal end of the axon of a neuron that contain synaptic vesicles? •Internodes •Synaptic knobs •Nodes of Ravier •Axon hillocks

Synaptic knobs

Neurons that have one axon & one dendrite, such as olfactory cells, certain neurons of the retina, & sensory neurons of the inner ear, are classified as which of the following? •Multipolar •Anaxonic •Unipolar •Bipolar

bipolar

The brain & spinal cord are components of the ____ nervous system, while the nerves & ganglia are components of the ____ nervous system.

central; peripheral

The knotlike swelling in a nerve where neuron cell bodies are found is called a(n) ____.

ganglion

Which division of the PNS carries signals from the CNS to glands & muscle cells? •Afferent •Endocrine •Sensory •Motor

motor

The autonomic nervous system is subdivided into the ____ division which tends to arouse the body for action & the ____ division which tends to have a calming effect.

sympathetic; parasympathetic

The axon hillock & initial segment play an important role in initiating a nerve signal. They are collectively called the ____ zone.

trigger

An axon lacking a myelin sheath is said to be ____

unmyelinated

Which factors influence the speed of nerve signal conduction? Select all that apply. •Size of soma •Diameter of axon •Presence of myelin •Type of neuron (multipolar vs. unipolar)

•Diameter of axon •Presence of myelin

Which types of glial cells are found in the CNS? Select all that apply. •Ependymal cells •Schwann cells •Oligodendrocytes •Satellite cells •Microglia •Astrocytes

•Ependymal cells •Oligodendrocytes •Microglia •Astrocytes

List the major cytoplasmic inclusions in a neuron. Select all that apply. •Melanin •Liquid droplets •Lipofuscin •Glycogen Granules •Synaptic vesicles

•Melanin •Liquid droplets •Lipofuscin •Glycogen Granules

Which two organ systems are primarily responsible for coordinating the other bodily systems so as to maintain homeostasis? Select two answers from the list below. •Cardiovascular system •Nervous system •Immune system •Endocrine system

•Nervous systema & endocrine system

Which are names for the cell body of a neuron? Choose all that apply. •Inclusion •Neurosoma •Soma •Ganglion •Astrocyte

•Neurosoma •Soma

Which are usually found inside the cell body (or soma) of a mature neuron? Check all that apply. •Nucleus •Rough endoplasmic reticulum •Synaptic vesicles •Mitochondria •Centrioles

•Nucleus •Rough endoplasmic reticulum •Mitochondria

Name the long neural process that generally conducts impulses away from the soma of the nerve cell.

Axon

Match the following terms with their description. Terms: •Axon hillock •Axoplasm •Axolemma •Axon collateral Definition: •Branch that originates from an axon •Plasma membrane of the axon •Cytoplasm of the axon •A mound located on one side of the soma from which the axon originates

Axon Hillock: A mound located on one side of the soma from which the axon originates Axoplasm: Cytoplasm of the axon Axolemma: Plasma membrane of the axon Axon collateral: Branch that originates from an axon

Categorize the six kinds of neuroglia according to whether they are found in the CNS or in the PNS. Astrocytes Ependymal cells Microglia Schwann cells Oligodendrocytes Satellite cells

CNS: Astrocytes Ependymal cells Microglia Oligodendrocytes PNS: Satellite cells Schwann cells

Sensory (afferent) neurons do which of the following? •Carry signals to glands •Carry signals to spinal cord and brain •Recieve incoming signals and initiate outgoing nerve signals •Carry signals to muscles

Carry signals to spinal cord & brain

Since neurons generally do not undergo mitosis after reaching maturity, which organelle do they lack? •Golgi apparatus •Ribosomes •Endoplasmic reticulum •Centrioles

Centrioles

____ are the processes of a neuron that usually receive signals from other neurons.

Dendrites

Neurons are classified structurally according to the number of processes extending from to soma. Match each classification to its description. Terms: •Multipolar neurons •Bipolar neurons •Unipolar neurons •Anaxonic neurons Description: •No axon; multiple dendrites •A single process •One axon; one dendrite •One axon; multiple dendrites

Multipolar neurons: One axon; multiple dendrites Bipolar neurons:One axon; one dendrite Unipolar neurons:A single process Anaxonic neurons:No axon; multiple dendrites

List the three functional classes of neurons. Select all that apply. •Motor neurons •Sensory neurons •Multipolar neurons •Unipolar neurons •Interneurons •Somatic neurons

Motor neurons Sensory neurons Interneurons

Neurons with numerous dendrites & a single axon are structurally classified as which of the following? •Unipolar •Anaxonic •Multipolar •Bipolar

Multipolar

Neurons are classified structurally according to the number of processes extending from the soma. Match each classification to its description. terms: •Multipolar neurons •Bipolar neurons •Unipolar neurons •Anaxonic neurons Description: No axon; multiple dendrites •No axon; multiple dendrites •A single process •One axon; one dendrite •One axon; multiple dendrites •

Multipolar neurons: Bipolar neurons Unipolar neurons Anaxonic neurons

Motor, or ____, neurons carry signals away from the CNS & they lead to effectors (muscle & gland cells.)

Efferent

Two organ systems are dedicated to internal coordination, communication, between the other systems, and maintaining the overall homeostasis of the body. They are the ____ system, which communicates by means of hormones, and the ____ system which send quick electrical and chemical messages from cell to cell.

Endocrine; nervous

Name the thin layer of fibrous connective tissue found around myelin in nerve fibers of the peripheral nervous system. •Axoplasm •Axolemma •Varicosity •Endoneurium

Endoneurium

Inclusions found in neurons include "wear-&-tear" granules that form when lysosomes degrade worn-out organelles & other products. What is the name of the golden-brown pigment that they contain? •Lipofuscin •Neurotransmitter •Melanin •Nissl bodies

Lipofuscin

Which term refers to the segment of an axon between the axon hillock & the first glial cell? •Initial segment •Terminal arborization •Trigger zone •Axon collateral

Initial segment

Which type of neuron lies within the CNS & carries out the integrative function of the nervous system? •Interneuron •Sensory •Autonomic •Motor

Interneuron

During axonal transport, motor proteins transport material as they crawl along microtubules. Match the type of axonal transport with its corresponding motor protein. Terms: •Kinesin •Dynein Description: •Retrograde transport •Anterograde transport

Kinesin: Anterograde transport Dynein: Retrograde transport

The myelin sheath is composed mostly of which of the following? •Carbohydrates •Lipids •Glycoproteins •Proteins

Lipids

List characteristics of neuroglia. •They blind neurons together and provide a supportive scaffold •Their main properties are excitability & conductivity •They protect the neurons & help them function •They are less numerous than neurons

They bind neurons together & provide a supportive scaffold. They protect the neurons & help them function.

What is the primary function of the myelin sheath? •To insulate the dendrites of a neuron •To increase the speed of signal conduction in the axon •To help keep neurons warm •To transmit nerve signals to adjacent cells

To increase the speed of signal conduction in the axon

True or false: Unmyelinated nerve fibers (axons) in the PNSare enveloped in Schwann cells.

True

Neurons with single process extending from the soma, such as the neurons that carry sensory signals to the spinal cord, are classified structurally as ____ neurons.

Unipolar

Neurons that have multiple dendrites but no axons, & which do not produce action potentials, are called ____ neurons.

anaxonic

Which terms refer to the passage of proteins, organelles & other materials along an axon? •Axonal transport •Secretion •Active transport •Synaptic signaling

axonal transport

Which type of glial cell aids in regeneration of damaged peripheral nerve fibers by forming a regeneration tube to help reestablish the former connection? •Schwann cells •Satellite cells •Oligodendrocytes •Ependymal cells

•Schwann cells

Which is true about a neuron with a large diameter, myelinated axon as compared to a neuron with a small diameter, unmyelinated axon? •Signal conduction will be slower •More neurotransmitter will be released •Signal conduction will be faster •Less neurotransmitter will be released

•Signal conduction will be faster

The visceral motor division of the PNS is also called the autonomic division. Which of the following are functions of this division? Select all that apply. •Stimulating or inhibiting digestion •Controlling gland secretion •Accelerating or decreasing heartbeat •Initializing contraction of skeletal muscles

•Stimulating or inhibiting digestion •Controlling gland secretion •Accelerating or decreasing heartbeat

In order for a peripheral nerve fiber to regenerate it must have which of the following? •The entire axon intact •At least part of the perikaryon intact •All dendrites intact •The soma & at least some neurilemma intact

•The soma & at least some neurilemma intact

Which statements are true about Schwann cells? Select all that apply. •They are only found in the CNS •They assist in the regeneration of damaged nerve fibers •They form the neurilemma •They form the myelin sheath in the PNS

•They assist in the regeneration of damaged nerve fibers •They form the neurilemma •They form the myelin sheath in the PNS