Ch.11: Nervous System Flashcards
the master controlling and communicating system of the body
Nervous system
3 functions of the nervous system
Sensory input, integration, motor output
Consist of the brain and spinal cord the control center of the nervous system
Central nervous sytsem
part of the nervous system outside the CNS, consist of mainly nerves that extend from the brain and spinal cord
Periphery nervous system
spinal nerves
carry impulse to and from the spinal cord
Cranial nerves
carry impulses to and from the brain
A PNS functional division, consist of nerve fibers that convey impulses toward the CNS from sensory receptor s keeps the CNS informed of events goin on both inside and outside of the body
Sensory (afferent) division
Convey impulses from the skin, skeletal muscles and joints
Somatic sensory fibers
transmit impulses from the visceral organs
Visceral sensory
_________ of the PNS transmits impulses from the CNS to effector organs which are the muscles and glands
Motor(efferent) division
somatic nervous system characteristics
somatic motor nerve fibers
conduct impulses from the CNS to SKELETAL MUSCLES
VOLUNTARY
autonomic nervous system characteristics
visceral motor nerve fibers
regulate activity of smooth muscles, cardiac, glands
INVOLUNTARY
Autonomic nervous system is broken into two subdivisions which are
Sympathetic and Parasympathetic
The five types of Neuroglial cells
astrocytes, microglial cells, ependymal cells, oligondendrocytes, and schwann cells
Characteristics of Astrocytes
most abundant, blood brain barrier, control chemical environment around neurons, mop up leaked potassium ions, anchor
Characteristics of Microglial cells
Monitor health, sense injury migrate towards it, macrophage, eat up debris
Characteristics of Ependymal cells
“wrapping up garment” , line central cavities of the brain and spinal cord, cerebrospinal fluid
Characteristics of Oligodendrocytes
Myelin sheath in the CNS, does not have nucleus, cannot be repaired
Characteristics of Schwann cells
Myelin sheath in the PNS, does have a nucleus, can be repaired
Characteristics of neurons
conduct messages, extreme longevity, not able to divide, and high metabolic rate (oxygen)
Rough ER of the neuron cell body is called
Chromatophollic substance
Bundles of intermediate filaments
neurofibrils
Clusters of cell bodies in the CNS
nuclei
Clusters of cell bodies in the PNS
ganglia
Bundles of neuron processes
Tracts
main receptive or input region
dendrites
generates nerve impulses and transmits them
axon
plasma membrane of neuron cell body
axolemma
movement away from the cell body
Anterograde movement
movement toward the cell body
Retrograde movement
Protects and electrically insulates fibers
myelin sheath
Myelinated fibers conduct nerve impulses
rapidly
Nonmyelinated fibers conduct nerve impulses
slowly
dense collections of myelinated fibers
white matter
______ contains mostly nerve cell bodies and nonmyelinated fibers
Gray matter
Characteristics of multipolar neurons
one axon, many dendrites
most abundant in the CNS
most common
Characteristics of bipolar neurons
One axon and one dendrite
rare neurons
found in special sense organs, such as eye, olfactory
Characteristics of Unipolar neurons
myelinated, peripheral process,and central process
found mainly in the PNS
common in the dorsal root of ganglia of the spinal cord and sensory ganglia of cranial nerves
Sensory afferent neurons transmit implulses
from sensory receptors in the skin or internal organs toward or into the CNS
Motor efferent neurons carry impulses
away from the CNS to the effector organs(muscles and glands) of the body periphery
Interneurons or association neurons are
between motor and sensory neurons in neural pathways and shuttle signals through CNS pathways where integration occurs. MAKE UP 99% OF THE NEURONS OF THE BODY
When a neuron is adequately stimulated, an electrical impulse is generated and conducted along the length of its axon
Action potential
the measure of potential energy generated by separated charge measured in volts or millivolts
voltage
the hindrance to charge flow provided by substances through which the current must pass
Resistance
the flow of electrical charge from one point to another
Current
Open when the appropriate neurotransmitter binds
Chemically gated, ligand gated
Open and close in response to changes in the membrane potential
Voltage-gated channels
The resting membrane potentials measures to
-70 Mv
A decrease in membrane potential, the inside of the membrane becomes less negative and close to 0
depolarization
An increase in membrane potential, the inside of the membrane becomes more negative and moves further away from 0
Hyperpolarization
Order of Action potential
resting state on -70 Mv threshold hits -55Mv reaches depolarization Na+ floods in Action potential Hyperpolarization, away from Zero becomes more negative returns to resting state
_________ it either happens completely or doesn’t happen at all
all or none phenomenon
The period where the neuron cannot respond to another stimulus, no matter how strong, the Na+ channels begin to reset to their original resting state
Absolute refractory period
The period where most Na+ channels have returned to their resting state, some K+ channels are still open, an exceptionaly strong stimulus can reopen the Na+ channels that have already returned to their resting state and generate another AP
relative refractory period
AP propagation involving nonmyelinated axons, these channels are immediately adjacent to each other, relatively slow
Continuous conduction
Electrical signals appears to jump from gap to gap along the axon, relatively fast
saltatory conduction
________ auto immune disease, gradually destroys myelin sheath
Multiple sclerosis
Characteristics of GROUP A FIBERS
mostly somatic sensory and motor fibers
serves skin ,skeletal muscles, and joint
fastest, myelinated
Characteristics of GROUP B FIBERS
lightly myelinated
serves temp, pain, touch,pressure
average pace
Characteristics of GROUP C FIBERS
non myelinated
incapable of saltatory conduction
serves smooth muscles, cardiac muscles, glands
slowest
the __ & __ fiber groups include autonomic nervous system motor fibers serving the visceral organs, visceral sensory fibers and the smaller somatic sensory fibers
B and C
A junction that mediates information transfer from one neuron to the next or from a neuron to an effector cell
Synapse
Contain protein channels connexons, electrically coupled, provide a simple means of synchronizing, eye movements,embryonic nervous tissue
electrical synapse
Allow the release and reception of chemical neurotransmitters, synaptic vesicles, depends on release ,diffusion and receptor binding of neurotransmitter molecules undirectional communication between neurons
Chemical synapse
Chemical synapse process
- action potential arrives at axon terminal
- Ca+ enters axons
- Synaptic vesicles release neurotransmitters
- Neurotransmitters diffuse synaptic cleft and bind to receptors
- binding open ion channel, graded potential
- reuptake
“language of the nervous system”
neurotransmitters
Characteristics of Acetylcholine
most abundant
released by all neurons that stimulate skeletal muscles
destroyed Acetylcholinesterase
Characteristics of Dopamine
Feel good
deficiency: parkinsons disease
overactive: schizophrenia
Characteristics of Serotinin
sleep, appetite, mood, migraine
Histamine
acid secretion in the stomach, wakefullness, appetite control and learning, memory
substance p
mediator of pain signals
endorphins
act as natural opiates, reducing our perception of pain under stressful conditions
