Chapter 13- Neural Tissue Flashcards
general makeup of neural tissue
many organs, composed of many tissues– CT, BV, neurons and neuroglia
two communication systems
nervous and endocrine
- coordinates all body systems
- accomplished by the transmission of signals (body to CNS) and (CNS to body)
- electrochemical signaling
- direct, fast, specific signaling
nervous system
- slow scale signaling
- long lasting signaling
- uses chemicals in the blood stream called horomones
endocrine system
2 divisions
central nervous system and peripheral nervous system
nervous system that involves brain and spinal chord
CNS
nervous system that involves cranial and spinal nerves
PNS
extension of CNS to communicate with appendicular limbs and body
PNS
- brain and spinal chord
- covered by meningies
- starts as hollow tube
- bathed in cerebrospinal fluid
- integration center
CNS
consists of cranial and spinal nerves hats contain both sensory and motor fibers
- connects CNS to muscles, glands, and all sensory receptors
- brings info to and from the CNS
PNS
sending things to the CNS
sensory fibers
sending things from CNS to organs
motor fibers
two types of peripheral nervous systems
afferent and efferent
part of peripheral nervous system that deals with sensory
afferent divison
part of peripheral nervous system that deals with motor
efferent division
two divisions of the efferent division of PNS
somatic division and autonomic division
efferent division of PNS that deals with conscious and voluntary
somatic
efferent division of PNS that deals with unconscious and involuntary
autonomic
general fxns of nervous system
receptors sensory integrative motor effector
makeup of nervous tissue
neurons and neuroglia
structural and functional units. excitable and amitotic. send signal from one part ot another. very specialized
neurons
accessory cells that act like CT. covers all things. support team of the neurons with diverse jobs
neuroglial cells
3 major structures of neuron
axon
dendrites
soma
cell body of neurons. mononucleate
soma
what soma consists of
nissl bodies, axon hillock, perikaryon, neurofibrils
part of the soma– involves ribosmees clusters, give grey color
Nissl bodies
part of the soma– connects soma to the axon
axon hillock
part of the soma– region around the nucleus
perikaryon
part of the soma– cytoskeleton that extend into dendrites/axons; gives shape
neurofibrils
- respond to neurotransmitters
- short branched, unmyelinated
- specialized for contact with other neurons
- conducts impulses towards the cell body
dendrites
only one per cell
- conducts nerve impulses away from the soma
- can give off collaterals
- many wrapped in myelin sheath
- dont have receptive surface
axon
branches off of the axon
collaterals
glial cells wrapped around the axon. help to increase speed of signal that is sent by
myelin sheath
structure end in the synaptic terminal
- produce neurotransmitters
- may contact: another neuron, muscle fibers, glands
axon
axoplasmic transport. movement of cellular materials through the axon– two types: anterograde and retrograde
axonal transport
type of axonal transport. moves material away from the soma; neurotransmitters, organelles, and nutrients
anterograde axonal transport
type of axonal transport. moves material toward the cell; degrade material to be recycled an extracellular substances
retrograde axonal transport
cytoplasm of an axon. consists of few organelles and cytoskeletal proteins that form cytoskeleton, maintain shape and generate axonal transport
axoplasm
purpose of cytoskeletal proteins found in the axoplasm
help to form cytoskeleton
- maintain shape
- generate axonal transport
plasma membrane of an axon. consists of collaterals, telodendria, synaptic terminal.
- have high concentration of ion channels – allow fir the influx of iions
axolemma
part of the axolemma– side branches
collaterals
part of axolemma– terminal extensions
telodentria
part of axolemma– contains synaptic vesicles where neuron contacts postsynaptic cell.
synaptic terminal
structural classification of neurons– based on number and morphology of dendrites
anaxonic
bipolar
unipolar
multipolar
small neurons, star looking, dont travel far, found in areas with lots of axons that dont need to communicate outside of the space. axons cannot be distinguished form dendrites. coordinate special sense
anaxonic
several small dendrites converge into one. dendrite and axon sperated by soma. unmyelinated. sensory neurons for specialized senses.
bipolar
also known as pseudo-unipolar. several sall dendrites converge into one large. dendrite and axon continuous—- soma doesn’t separate. usually unmyelinated. majority found in PNS. no receptive surface on the soma
unipolar
many dendrites extend from the soma. long axon. myelinated. majority = motor neurons in PNS. lots of inputs and 1 output
multipolar
have sensory function. cell body usually outside of CNS. have receptor end on dendrites or are associated with receptor cells in sense organs. carry impulses from peripheral body parts to the brain or spinal cord.
afferent neurons
afferent neurons 3 receptors
exteroceptors, propioceptors, interoceptors
type of afferent neuron receptor that deals with external stimuli– touch temperature, pressure, light, and chemicals
exteroceptors
type of afferent neuron receptor that deals with muscle and skeletal positions within space
propioceptors
type of afferent neuron receptor that deals with monitoring internal stimuli/systems– digestion, respiration, urinary
interoception
- only within the CNS
- classified based on effects (excitatory and inhibitory)
interneurons
have motor functions. cell body usually inside of the CNS. carry impulses from teh brain or the spinal cord to peripheral body parts
efferent neurons
types of efferent neurons
somatic and autonomic/visceral
type of efferent neuron that controls skeletal muscle
somatic efferent neurons
type of efferent neuron that deals with smooth muscle and glands
autonomic/ visceral efferent neurons
neuroglial cells in CNS
astrocytes, oligodendrocytes, ependymal cells, microglia
neuroglial cells in PNS
satellite and schwann cells
largest and most common neuroglial cells. star shaped . responsible for structure and repair, metabolsim, regulate ions and nutrition, guide neurons to target, and form blood barrier
astrocytes
type of neuroglial cell–like astrocytes, but smaller. responsible for forming myelin in the CNS, sequester debris
oligodendrocytes
type of neuroglial cells that is the smallest and least common. derived from myeloid cells. responsible for supporting neurons, function as phagocytes, and increase in number during injury or disease
microglia
type of neuroglial cell that is columnar/cubodial. have microvilli on luminal surface. joined by gap junctions. function: produce cerebrospinal fluid, form porous layer, and monitor CSF composition
ependymal
type of neuroglial cell found in the PNS. associated with the soma. assist with exchange of nutrients . isolates neuron form extraneous stimuli. no blood brain boundary. manages chemicals and nutrients going into the soma
satellite
type of neuroglial cell found in the PNS. produce myelin in PNS. encloses axons of longer peripheral nerves. functions: support neuron, prevent contact, myelinate large PNS axons
schwann Cells
myelin structures
myelin, neurilemma, nodes of ranvier
part of myelin structure– plasma membrane of the schwann cell wrapped around axon
myelin
part of myelin structure– part of schwann cell that contains cytoplasm– not part of the myelin
neurilemma
part of myelin structure– gaps in myelin sheath where changes of charge occur at nodes
nodes of ranvier
fxn of myelin
isolate axons and increase rate of action potetnial
ability to respond to stimuli
irritability
ability to transmit an impulse
excitability
an electrical impulse changing the permeability of a membrance
action potential
action potential moving down an axon
nerve impulse
when does nerve impulse travel faster?
axon is myelinated, has a larger diameter
characteristics of synapse
- function as a control/transmission point
- site of communication between sensory structure and neuron, neuron and effector, 2 neurons, and two cells with gap junction
2 types of synapses
electrical and chemical
type of synapse– gap junction cause the exchange of charged ions between two cells
electrical synapse
type of synapse– chemicals are released by one cell and travel to another
chemical synapse
way in which afferent fibers can branch as they enter a neuronal pool
convergence, divergence, serial processing, parallel processing, reverberation
type of neuronal pool– one neuron to another in a series
serial processing
type of neuronal pool– when impulse leaves a pool, it spreads into several outputs. allows impulse to be amplified. has collaterals to help proliferate and amplify impulse
divergence
type of neuronal pool– single nerve in pool may receive impulses from 2 or more incoming fibers. many fibers lead to same nerve to converge. allow for summation of impulses from different sources
convergence
type of neuronal pool– processing info from several neurons at once. one cell has collateral and proliferate signal down multiple paths
parallel processing
type of neuronal pool— positive feedback loop continues activity of circuit until something inhibits it
reverberation
structures of CNS
nuceli, center, and tracts
collection of neuron cell bodies– grey matter
nuceli
collection of neuron cell bodies working together
center
bundles of axons. white matter. signal produced by great matter going through axons in this…
tracts
PNS structures
ganglia and nerves
collection of neuron cell bodies
ganglia
bundles of axons
nerves