Module 1 Lab

Axon hillock

The conical (cone-shaped) region of a neuron's axon where it joins the cell body; typically the region where nerve signals is generated.

In the PNS, unmyelinated fibers are enveloped in Schwann cells

True

Bipolar neuron

a neuron with one axon and one dendrite attached to its soma

unipolar neuron

a neuron with one process extending from its cell body

Myelin sheath

covers the axon of some neurons and helps speed neural impulses

Schwann cells

form myelin sheath in PNS, insulate neurons and enhance the rate of transmission in the PNS

anaxonic neuron

many dendrites but no axon, help in visual processes

Astrocytes

multi-functioning cells involved with neurogenesis, scar formation, blood brain barrier maintenance most abundant CNS glial cells

ependymal cells

produce and circulate cerebrospinal fluid

Satellite cells

support cells in the PNS that surround neuronal cell bodies surround neuron cell bodies in PNS

Axon

the extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands (away from)

synaptic cleft

The narrow gap that separates the presynaptic neuron from the postsynaptic cell.

Soma of neuron

cell body, contains nucleus

Microgila

macrophages of the CNS

Synapse

the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

Why is myelin important?

- It speeds up signal conduction in the nerve fiber - It is formed to assist in the regeneration of damaged fibers - It insulates the nerve fiber

Place the following structures in the order that an electrical impulse would travel beginning with the postsynaptic membrane

1. Dendrites 2. Soma 3. Axon hillock 2. Axon 5. Presynaptic terminals

Node of ranvier

A gap between successive segments of the myelin sheath where the axon membrane is exposed.

Multipolar neuron

A neuron with a single axon and multiple dendrites; the most common type of neuron in the nervous system.

mulitpolar neuron

A neuron with a single axon and multiple dendrites; the most common type of neuron in the nervous system.

Which of the following characteristics is common to oligodendrocytes and Schwann cells?

Both provide myelination

Dendrites

Branchlike parts of a neuron that are specialized to receive information.

Which of the following parts of a neuron receives and processes information?

Cell body

Schwann cells are glial cells of the central nervous system

False

The Schwann cell's plasma membrane spirals repeatedly around the unmyelinated fiber as it does in a myelin sheath.

False

Oligodendrocytes

Form myelin sheath in CNS

Choose the correct statement about myelin

It is best not to give children under two years of age a low-fat diet because myelin formation requires lipids