Quiz 7 - Nervous Tissue Flashcards
overview of nervous system
- control and adjust the activities of other organs
- relatively swift and brief responses
two parts of nervous system
central nervous system and peripheral nervous system
CNS
- brain and spinal cord
- integration, processing and command center
PNS
- nerves
- carries messages to and from CNS
two different types of functions
afferent/sensory division or efferent/motor divison
afferent/sensory division
nerve fibers that carry information from sense organs TO the CNS
efferent/motor division
nerve fibers that carry information FROM the CNS
where does efferent/motor division send information to
somatic nervous system and autonomic nervous system
somatic nervous system
(voluntary) - skeletal muscles
autonomic nervous system
(involuntary) - cardiac and smooth muscles, glands
parasympathetic
“rest and digest” system
sympathetic
“fight or flight” system
neurons
nerve cells - specialized to transmit electrical impulses
cell body
contains nucleus, mitochondria, ribosomes and other organelles
- metabolic center of cell
- contains large nucleus and nucleolus
dendrites
stimulated by environment changes or the activities of other cells
- processes conduct impulses TO the cell body
- receives information from other neurons
axon
conducts nerve impulses (action potential) toward synaptic terminals
axon hillock
tapering section of cell body from which axon arises; generates action potentials (electrical signal)
conducting region
carries electrical signals in one direction toward synaptic terminals
synaptic terminals
secrete neurotransmitters (chemical messengers) to another neuron or effector
neuralgia of CNS
“nerve glue”
- general functions: support, insulate and protecting neurons
- smaller than neurons - helper cells for neurons
ependymal cells
- line the central cavities of the brain and spinal cord
- usually assist in monitoring composition of and circulating cerebrospinal fluid
cerebrospinal fluid (CSF)
fluid circulated in the nervous system that transport dissolved gases, nutrients, wastes, etc.
- acts as ‘cushion’
astrocytes
- most abundant, versatile and highly branched glial cells
- cling to neurons and capillaries
things astrocytes do
- maintain the blood brain barrier
- create 3-D framework for CNS
- repair damaged neural tissue
- guiding neuron development
- controlling interstitial environment
microglia
- small with spiny processes
- phagocytes that remove cell debris, wastes and pathogens
oligodendrocytes
produce insulating myelin sheath around nerve fibers in CNS
myelin
- fatty material that protects and insulates nerves
- speeds up transmission rate of nerve impulses
- makes nerves appear white
neuroglia of the PNS
satellite cells
schwann cells
nodes of ranvier
satellite cells
surround ganglia (cell bodies), regulate exchange of nutrient and waste products between neuron cell body and extracellular fluid (ECF)
schwann cells
cells that form myelin sheath (neurolemma) around peripheral axons
nodes of ranvier
gaps in myelin sheath along axon
- impulses travel faster when fibers have a myelin sheath
- allows impulses to “jump” from node to node
white matter
cell bodies and unmyelinated fibers
gray matter
mylinated fibers
differences between neuroglia and neurons
- glia cannot transmit nerve impulses like neurons
- glia retain ability to divide (unlike neurons)
- most brain tumors are gliomas
- there are more glia than neurons (5x as much as neurons)
