chapt 12 vocab

12.2c anterograde transport

movement of materials from cell body toward synaptic knobs

12.2c retrograde transport

movement of materials from synaptic knobs toward cell body

12.2c fast axonal transport

• occurs at about 400 milimeters per day

• movement along microtubules

• substances can be moved either direction (anterograde/retrograde)

12.2c slow axonal transport

• occurs 0.1-3 mm a day

• results from flow of the axoplasm

• moves only 1 direction (anterograde)

ex: enzymes, cytoskeletal components, & new axoplasm

12.3 synapse

specific location where a neuron is functionally connected to another neuron/effector

12.3 chemical synapse

• composed of presynaptic neuron (signal producer) & postsynaptic neuron (signal receiver)

• uses neurotransmitters

• has a synaptic delay

12.3 electrical synapse

• composed of presynaptic neuron (signal producer) & postsynaptic neuron (signal receiver) that are physically bound together

• gap junctions present

• no synaptic delay

• located in regions of brain & eyes

12.4a glial cells

supports neurons with their functions

no electrical signals

12.4b astrocyte functions

• helps form blood brain barrier

• regulates instertital fluid

• provides structural support & organization to the CNS

• assists with neuronal development

• alters synaptic activity

• replicates to occupy space of dying neurons

12.4b ependymal cell functions

• lines ventricles of brain & central canal of spinal cord

• assists in productions & circulation of CSF

12.4b microglial cell funcitons

• phagocitizes microorganisms & potentially harmful substances

• phagocytizes unnecessary synapses between neurons

12.4b oligodendrocyte functions

• myelinates & insulates CNS axons

• allows faster propagation of action potentials along axons in CNS

12.4b glial cells of CNS

1. astrocyte

2. microglial cells

3. ependymal cells

4. oliodendrocyte

12.4b glial cells of PNS

1. satellite cells

2. neurolemmocytes

12.4b satellite cell functions

1. insulates PNS cell bodies

2. regulates nutrient & waste exchange for bodies in ganglia

12.4b neurolemmocyte functions

• myelinates & insules PNS axons

• allows faster propagation of action postentials along an axon in the PNS

12.6a pumps

• maintain concentration gradient by moving substances across plasma membrane (up)

• active transport (uses ATP)

12.6a channels

• maintains concent. gradient by moving substances across plasma membrane by facilitated diffusion (no atp)

• moves down

12.6a leak channels (passive)

• always open

• allows continuous diffusion of a specific ion

12.6a chemically gated channels

• typically closed

• temporarily open in response to binding of a neurotransmitter

• when open only allow a specific type of ion to diffuse across p.m.

12.6a voltage gated channels

• typically closed

• temporarily open in response to changes in voltage at plasma membrane

• when open only allows specific type of ion to diffuse across p.m.

12.6a modality gated channels

• function in sensory receptors

• located on dendritic endings of sensory neurons

  • detect changes in external/internal environment

• open/close in response to a specific type of sensory stimulus (change in temp, pressure, light)

12.6a 3 stages of voltage gated Na+ channels

1. resting state

2. activation state

3. inactivation state

12.6a 3 stages of voltage gated Na+ channels

resting state

• inactivation gate is open

• activation gate is closed

• closed activation prevents entry on Na+

12.6a 3 stages of voltage gated Na+ channels

activation state

• both inactivation gate & activation gate are open

• Na+ moves into cell through open channel

12.6a 3 stages of voltage gated Na+ channels

inactivation state

• inactivation is temporarily closed

• activation gate is open

• closed inactivation prevents entry of Na