nervous tissue Flashcards
The Central Nervous System (CNS) includes:
a) The brain and spinal cord
The axon hillock is responsible for:
Generating an action potential.
The axon hillock is the site where action potentials are generated.
Schwann cells form myelin in the ?
PNS
The nodes of Ranvier
are gaps in the myelin sheath.
Myelin in the CNS is formed by?
Oligodendrocytes
Saltatory conduction refers to?
The leaping of an impulse from one node to another, speeding up transmission
Sensory neurons carry impulse ____ the CNS
“toward” the CNS
Bipolar carry impulses for the?
special senses. (sight, hearing, smell)
Bipolar have ___ processes, a single dendrite and an axon
two processes
Multipolar have ____ dendrities with ___ axon
multiple dentrites along 1 axon
T/F. Multipolar make up all motor neurons and interneurons found in the CNS. (99% of all neurons)
T
4 types of Neuroglia
- Microglia
- Astrocytes
- Oligodendrocytes
- Ependymal cells
What is Microglia?
are macrophages that can phagocytize microbes and clean up cellular debris
Astrocyte is the most____ of all glial cells
most abundant
Astrocytes
by connecting nuerons with blood vessels, they participate in the blood brain barrier and control the permeability of vessels
- from scar tissue, when nuerons are damaged in the CNS
- control potassium levels in the intersitial speces and clean up neurotransmitters
Oligodendrocytes provide ___ in the CNS that have A or B fibers
myelin
Ependymal cells line ____ and ____ of brain and spinal cord
canals and cavities.
What are the 2 types only found in the PNS
- Schwann cells
- Satallite cells
Ependymal cells help?
produce and move cerebrospinal fluid
What do satellite cells do?
wrap the cell bodies of neurons found din the PNS
help control the chemical environment of the cell.
Nervous tissue is composed of ___, the cells that create nerve impulses to send and receive messages, and ____ , a variey of support cells.
neurons, and neuroglial cells
Cell body is filled with?(soma)
perikaryon (granular cytoplasm)
contains nissl bodies, endoplamis and rbiosomes around nucleus
contain neurofibrils : intermediate filaments that form the cytoskeleton.
has no centrioles so cells are not mitotic.
The axon forms tracts in the ?
CNS and nerves in the PNS
