Chapt 13. Anatomy Nervous Tissue

center

collection of neural cell bodies in the CNS

tract

group of cell axons in central nervous system

column

groups of tracts in central nervous system

nerve

bundle of axons in peripheral nervous system

ganglion

is a bundle of cell bodies in the peripheral nervous system

two branches off of the peripheral nervous system

afferent and efferent

afferent

communication towards the central nervous system

what nerve fibers does the afferent division include

sensory

what nerve fibers does the efferent division include

motor

efferent

communication away from the central nervous system

two branches off of efferent pathways

somatic nervous system and autonomic nervous system

somatic nervous system is

voluntary motor and deals with skeletal muscle

autonomic nervous system is

visceral motor involuntary and deals with smooth muscle, glands, and cardiac muscle

the two branches of off autonomic nervous system

sympathetic and parasympathetic

what does sympathetic

mobilizes body

what does parasympathetic

conserves energy

neuroglia within the CNS

ependymal cells, microglia, astrocytes, oligodendrocytes

ependyml cells

lines cavities with cerebrospinal fluid and is often ciliated

microglia cells

phagocytic immune cells

astrocytes

provide structural support, regulate interstitial fluid, maintain brain blood barrier, repair damaged tissue

oligodendrocytes

provide structural support, myelinate axons

PNS nueroglia

satellite cells, schwann cells

satellite cells

surround neuronal cell bodies and isolate neurons from other stimuli and regulate the exchange of nutrients and waste products with interstitial fluid

schwann cells

forms myelin sheath around axon in pns

nuclei

bunch of cell bodies in central nervous system

what do the dendrites do

convey signals

what do axons do

conduct impulses from cell body to axon terminal

nodes of ranvier

separate internodes and allows electrical signal to travel quicker

epineurium

dense connective tissue that surrounds nerve

perineurium

connective tissue that surrounds the nerve fascicle

endoneurium

connective tissue that surrounds nerve fiber

anaxonic neuron

dendrites and axons cannot be distinguished

bipolar neuron

2 processes that are separated by the cell body

pseudounipolar neuron

1 process with the body positioned to the side

multipolar neuron

more than two processes. Single axons and multiple dendrites

cell body connects to all of the branching projections

wallerian degeneration

carried out by Schwann cells that break down, clear, and restore damaged nerves.

adult neurogenesis

new neurons are generated by stem cells in the brain

neuromuscular junction

neuron to muscle

neuroglandular junction

neuron to gland

synapse

junction that mediates information between a neuron and another cell

presynaptic neuron to post-synaptic neuron

neuron to neuron

what type of transmission can synapses do

electrical, chemical, and mixed

interneurons

only within the CNS and account for 99% of all neurons in the body; they process sensory info and then decide which motor neurons to relay a message to

different functional classifications of neurons

sensory (afferent), motor (efferent), and interneurons

sensory neurons are mostly

unipolar neurons

motor neurons are mostly

multipolar

interneurons are mostly

multipolar

sensory neurons do what

transmit sensory signals to the CNS

motor neurons do what

send signals away from the CNS; they trigger movement, either involuntary or voluntary

neural pool

interconnected neurons

neural circuit

the way the neural pool is organized

divergence

signal is taken and amplified

convergence

the circuit provides input to a single source

serial processing

signal is step-by-step transmission in a linear sequence

parallel processing

process signal at same time through different pathways

reverberation

positive feedback circuit

output neuron sends the signal back