Flashcards in Nervous Tissue CH 11 Deck (41):
Functions of the nervous system
1.Sensory input (PNS)
2. Integration (CNS)
3.Motor output (PNS)
Peripheral Nervous System (PNS)
Not including the CNS (brain and spinal cord)
Consists or spinal and cranial nreves
PNS functional subunits
Sensory "carrying towards"
1. Somatic sensory fibers: convey impulses from skin, muscles and joints
2. Visceral sensory fibers: transmit from visceral organs (in ventral body cavity)
Motor "carrying away"
1.Somatic NS: voluntary, controls skeletal muscles
2. Autonomic NS: involuntary, controls heart pumping digestion ect.
Neuroglia (or glial cells)
6 cells that make us neurons:
Neuroglia of the CNS
Neuroglia of the PNS
Most abundant & versatile
Making exchanges between capillaries and neurons
Mopping up leaked K+
Recycling released neurotransmitters
Type of macrophage
Phagocytize microorganisms and neural debres
Line CNS cavities
Cilia helps circulate CSF
Form myelin sheaths around CNS fibers
unknown function may be similar to astrocytes
Vital for regeneration of peripheral nerve fibers.
Form myelin sheath
Similar to oligodendrocytes
Receptive, input region
Each neuron has many dentrites
Motor neurons, off the cell body
Short, tapering, diffusley branching extentions
Each neuron has one axon
long axon = nerve fiber
cone shaped initial region of the axon
Extend from axon at right angles
knoblike distal ends of axon terminal branches
White, fatty fibers (protein-lipiod)
Protects, electronically insulates and increases speed on nerve impulse
Only on axons not dendrites.
Myelinated regions of the CNS, primary fiber tracts.
Unmyrlinated fibers and contains mostly nerve cell bodies.
Nodes of Ranvier
Gaps in myelin sheath
Neuron structural classifications
3 or more processes (1 axon the rest dendrites)
Major type in CNS
(1 axon 1 dendrite)
retina and olfactory mucosa
Single short process
emerges from cell body
divides T-like into proximal and distal branches
Found in PNS ganglia
lie between sensory and motor
Nerve impulse, conduction impulse that travels down the axon.
Potential energy generated by separated charge.
Flow of electrical charge from one point to another
The hindrance to charge flow provided by substance it passes through
2 membrane ion channels
1. Chemically gated
2. Voltage gated
Chemically gate ion channels
Open when neurotransmitter binds
Voltage gated ion channels
Open and close in response to changes in membrane potential.
Resting membrane potemtial
The potential difference in a resting neuron
Generating resting membrane potential depends on:
1. Differences in K+ and Na+ concentrations in and out of the cell.
2. Differences in permeability of plasma membrane to those ions.
Change in membrane potential can produce:
1. Graded potentials:Incoming signals over short distances
2. Action potentials: long dostance signals of axons
Decrease in membrane potential