chapter 11 part 3

Question 1

Structural classification of neurons–

Answer 1

based on number of dendrites

Question 2

Multipolar neurons

Answer 2

most neurons in CNS; motor neurons.

Question 3

Bipolar neurons

Answer 3

sensory in retina of the eye and nasal cavity.

Question 4

Pseudo- unipolar neurons

Answer 4

single process that divides into two
branches. Part that extends to the periphery has dendrite-like
sensory receptors.

Question 5

Anaxonic neurons

Answer 5

no axons, only dendrites; found in brain and retina
where they only communicate using graded potentials.

Question 6

GLIAL CELLS OF THE C N S: ASTROCYTES

Answer 6

• Star-shaped with processes that form feet that
  cover the surfaces of neurons, blood vessels, and
  the pia mater. Lots of microfilaments for support.
• Regulate extracellular brain fluid composition.
• Produce chemicals that promote tight junctions to
  form blood-brain barrier to regulate what
  substances reach the CNS from the blood.
• Reactive astrocytosis in which CNS injury sites
  are walled-off to limit spread of inflammation.
• Release chemicals to promote development of
  synapses and help regulate synaptic activity.

Question 7

GLIAL CELLS OF THE C N S: EPENDYMAL CELLS
YESS

Answer 7

• Line brain ventricles and spinal cord central canal. Specialized versions of ependymal form choroid plexuses.
• Choroid plexus within certain regions of ventricles. Secrete cerebrospinal fluid. Cilia help move fluid thru the cavities to the brain. Have long processes on basal
  surface that extend within the brain tissue, may have astrocyte-like functions

Question 8

GLIAL CELLS OF THE C N S: MICROGLIA

Answer 8

• Microglia: specialized CNS
  macrophages.
• Respond to inflammation, phagocytize necrotic tissue,
  microorganisms, and foreign substances that invade the CNS.

Question 9

GLIAL CELLS OF THE C N S: OLIGODENDROCYTES

Answer 9

Oligodendrocytes: form insulating myelin sheaths by
wrapping cytoplasmic extensions around axons. A
single oligodendrocyte can form myelin sheaths around
portions of several axons.

Question 10

Schwann cells

Answer 10

Glial cell of the PNS
wrap around portion of
only one axon to form myelin sheath.
Outer layer of the wrap is the
neurilemma that contains most of the
cytoplasm, nucleus and organelles. Cell
membrane primarily phospholipid.

Question 11

Satellite cells:

Answer 11

Glial cell of the PNS
surround neuron cell bodies in sensory and autonomic ganglia
* provide support, nutrients, and
protection from heavy-metal poisons.

Question 12

the two Glial cells of the PNS

Answer 12

Schwann cell and satellite cell

Question 13

Myelinated axons.

Answer 13

• Myelin protects and insulates axons from one another,
  speeds transmission, functions in repair of axons.
• Not continuous; gaps called nodes of Ranvier.
• White matter
• Degeneration of myelin sheaths occurs in multiple
  sclerosis and some cases of diabetes mellitus.

Question 14

Unmyelinated axons:

Answer 14

rest in invaginations of Schwann
cells or oligodendrocytes. Not wrapped around the axon;
gray matter.