I. NERVOUS SYSTEM
A. Central nervous system
1.___________________________________
2.____________________________________
B. Peripheral nervous system:receptors & nerves that connect brain & spinal cord
to rest of body
1.______________________________
a. Voluntary control
1.) Peripheral nerves that communicate with __________________________ &
;
_____________________________; concerned with changes in
external environment
2.____________________________
a._______________________ functions automatically; peripheral nerves that
communicate with visceral organs and monitor changes in _______________
environment
1.) Smpathetic system ---FIGHT OR FLIGHT
2.) Prasympathetic system --returns us to homeostasis
C. Functions of nervous system
1. Sensory: detects changes in ____________________ & __________________
conditions
2. Integrative: brings sensations together; decisions made
3. Motor: action taken
D. Nervous tissue: made of neurons and neuroglia
1. neuron = nerve cell: Fig. 10.1 and 10.3
a. Cell body contains:
1.) Nucleus & _____________________; but, NO MITOSIS OCCURS (why?)
2.) Mitochondria, Golgi apparatus, lysosomes,
3.) Nissle bodies (chromatophilic substance) clumps of _______________________________; (protein synthesis);
4.) Cytoskeleton -- microtubules, microfilaments, neurofilaments
a.) Microtubules -- _________________; form tracks in axon,
organelles move along these tracts.
5.) Microfilaments --________________; under the membrane, anchored to membrane.
6.) Neurofilaments -- main support system; network of threads that go into cell processes.
b. Dendrites
1.) transmit nerve impulses toward cell body
2.) dendritic spines == form __________ with other neurons.
c. Axon == ________________________________; carries impulses away
from cell body.
1.) axon hillock == thickened area of cell body where axon originates;
2.) axoplasm, axolemma, collaterals (branches of axons), specialized
endings known as axon terminals; ends of axons, END KNOBS
d. Sheaths of Axons in PNS �Fig. 10.4 a, b, c
1.)____________________________________ -- provides insulation; a
lipid rich plasma membrane
2.)____________________________________ == cellular sheath
3.) NODES OF RANVIER -- gaps between Schwaan Cell
4.) Neurilemma == ____________________________ -- the guide for
regenerating axons; made from bulk of Schwann cell which is outside myelin
e. Classification of neurons (sketch each type beside the definition) Fig. 10.6
1.) Multipolar
2.) Bipolar:
3.) Unipolar:
f. Types of neurons
1.)_________________________ == afferent == toward; detects changes
inside & outside body; transmits impulses about changes to processing
centers in brain & spinal cord. _______________
2.)_________________________________ -- integrative function; gather
info, integrate it, act on it; form memory, thoughts
3.)__________________________________-- efferent = away from; sends
impulses to muscles & lands causing a response ____________________
g. Mechanisms for transport in the NEURON
1.) Axoplasmic flow == transports axoplasm & protein from cell body to
___________________
a.) HOW FAST? ________________
b.) HOW? _________________
c.) WHY & WHEN DOES THIS OCCUR?
d.) When axons regenerate
e.) To renew axoplasm
2.) Axonal transport
a.) Faster -- 400 mm/day to or from cell body
b.) Uses microtubules that form stationary tracks; organelles move
on tracks; _____________________
h. Function of neurons:
1.) Afferent --_______________________
2.) Efferent _________________________
3.) Association
2. Neuroglia:Fig. 10.8 glial cells == neuroglia == _______________
Provide structural support; glial cells in CNS --- more numerous than neurons
a. Types of glial cells
1.) Oligodendrocytes -- smaller than astrocytes; found in ____________;
wraps membrane around neurons in brain & spinal cord == forms the
MYELIN SHEATH
2.) Astrocytes --STAR SHAPED -- between blood vessels & ___________
a.) forms _______________________________________
b.) structural support
c.) seals off damaged tissue
d.) forms __________________________________ to fill up spaces
after injury
e.) probably helps with nutrition
3.) Ependymal cells ___________________________________________
forms membrane 1 cell thick; lines ventricles (spaces in brain) &
central canal of cord.
4.) Microglia -- tiny brain _________________________________respond during injury; ________________after an injury; phagocytize bacteria & junk.
b. GLIAL CELLS IN PNS that form myelin sheath == ____________________
E. Terms: (Fig 11.24)
1. Epineurium -- connnective tissue _________________ an entire ___________________
2. Perineurium -- connective tissue ________________________ of
_____________________
3. Endoneurium -- connective tissue around ______________________________.
4. Ganglia -- groups of nerve __________________________________________
outside CNS
5. Nuclei or centers -- groups of nerve __________________________________
inside CNS
6.Tracts == _______________________ of axons inside the CNS
F. Neural Function:
1.__________________________--sensory neuron takes messages from visual,
auditory, olfactory, & touch receptors
2. __________________________ -- by sensory neuron to CNS
3. __________________________ -- correct response determined here
G. Motor neurons transmit to EFFECTORS == response == muscles & glands are the
main effectors
H.____________________________- == junction between 2 neurons or a neuron &
an effector
I. Reflex action -- simplest example of a NEURAL RESPONSE *****************
J. Receptors:
1. Sense organs == ______________________________________________________________
2. Sensory receptors in skin
3. Muscle spindles & golgi tendon organs -- sensitive to change in _____________
4. NOTE THAT ALL MESSAGES FROM RECEPTORS ARE THE SAME. The CNS "KNOWS" the message by knowing WHICH neuron delivered it.
K. Regeneration of nerve fibers FIG. 10.10
1. Learn steps of nerve regeneration; read "Regeneration of Nerve Fibers" in text.
2. Sketch:
L. Transmission along neurons: FIG. 10.10, 10.11, 10.12, 10.13, & 10.14
1. ELECTROCHEMICAL--depends on change in ___________ DISTRIBUTION
2. Neuron has a RESTING POTENTIAL == MEMBRANE POTENTIAL ==
difference in potential between both sides of membrane == an imbalance in electric
charge across plasma membrane.
3. WHAT ACCOUNTS FOR DIFFERENCES IN CHARGE?
1.) Large protein anions
2.) Outward diffusion of K+ ----> K+ leaks out, but Na+ does NOT leak in
Sketch:
4. RESULTS: potential difference of -70millivolts
M. Neural Impulse == _________________________________________
1. Neuron contains -- Na+ K+ pump
2. Passive ion channels
3. Voltage activated ion channels == gates can open/close, open/close
4. Sketch:
1). RESTING/DEPOLARIZATION/REPOLARIZATION
a.) Absolute Refractory Period -- the millisecond that the neuron is depolarized
we cannot transmit another impulse no matter how great the stimulus.
b.) Relative refractory period -- occurs while resting condition is being reestablished; in this case, a very strong impulse can stimulate the neuron
5. CAN A NERVE FIBER BE STIMULATED CONTINUOUSLY?
N. Continuous conduction of an impulse occurs on ___________________ neurons
O. Saltatory conduction FIG. 10.16; read section under "Impulse Condution"
1. occurs in _____________________ neurons;
2. Myelin acts as an insulator around an axon; the impulse jumps from node to
node to node to node to node.
3. Saltatory conduction is ___________X faster & uses less energy.
4. Why?-- only nodes depolarize, so fewer ______________________________;
cell does not have to work as hard to reestablish resting conditions.
P. ALL OR NONE LAW -- if stimulus is _______________________________,
neuron will fire.
1. If this is true, how can one response be greater than another?
a.The intensity of the response depends on the ____________________ of
_______________ stimulated and their ____________________________- of discharge.
Q. The synapse FIG. 10.17 & 10.18
1. Presynaptic neurons, post synaptic neurons and the synapse
2. Synaptic potentials
R. Neurotransmitters
1.Acetylcholine
2. Monoamines
3. Amino acids
4. Peptides
a. Enkephalins
b. Substance P
S. Neurotransmitters � action Table 10.6
1. Made in cytoplasm of synaptic knobs
2. Stored in synaptic vesicles
3. AP increases permeability of synaptic knob to calcium ions (channels open)
4. Calcium ions diffuse in; synaptic vesicles fuse with presynaptic membrane;
release neurotransmitter by exocytosis
5. How is the duration of the signal kept short?
T. Neuropeptides
1. Enkephalins, painful stress and opiate receptors
2. Beta endorphin � pain reliever
3. Substance P � pain transmitter
U. Impulse processing and neuronal poolsFIG. 10.20
1.Facilitation
2.Convergence
3.Divergence
V. How drugs control/or destroy:
1. Stop the chemical reactions that create neurotransmitters.
a. Ecstasy -->effects serotonin and midbrain dopamine systems resulting in the progressive degeneration of nerve terminals.
2. Empty neurotransmitters from the vesicles where they're stored and protected from breakdown by enzymes.
a. amphetamine -->increase release of dopamine
b. monoamine oxidase (MAO) -breaks down dopamine in synapse
1.) reserpine - prevents reuptake of dopamine -->MAO breaks down dopamine --depression
2.) deprenyl - inhibits MAO -->dopamine remains in synapse
3. Block neurotransmitters from entering and leaving vesicles
a. Opiates (morphine) - inhibit the release of substance P
4. Bind to receptors in place of neurotransmitters -
a. LSD ---replaces serotonin --> hallucinates
b. caffeine --->replaces adenosine --> facilitates
5. Prevent neurotransmitters from returning to their sending neuron (reuptake) -
6. Interfer with second messengers, the chemical and electrical changes that take place in a receiving neuron.