AP Ch 9 Flashcards
(know) axons carry impulses away from the neuron cell bodies and dendrites carry impulses to the neuron cell bodies
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___ carry impulses to the spinal cord and brain from all parts of the body. They are also called afferent neurons
sensory neurons
___ carry impulses away from the brain and spinal cord. They only conduct impulses to two kinds of tissue, muscle and glandular epithelial tissue. They are also called efferent neurons
motor neurons
___ conduct impulses from sensory neurons to motor neurons. They also connect with each other to form complex, central networks of nerve fibers. They are sometimes called Central or Connecting neurons
interneurons
The 3 main functions of glia
#1 hold functions neurons together and protect them #2 Regulation of neuron function #3 bring the various functions of nervous tissue together into a coordinated whole
___ attach to neurons and to small blood vessels, holding these structures close to each other
astrocytes
___ separates the blood tissue and nervous tissue to protect vital brain tissue from harmful chemicals that might be in the blood
Blood-brain barrier (BBB)
___ remain stationary, but in inflamed or degenerating brain tissue, they enlarge, move about, and acts as a microbe-eating scavengers. They surround the microbes, draw them into their cytoplasm, and digest them. They likewise help to clean up cell damage resulting from injury or disease
Microglia
___ holds nerve fibers together and produces the fatty myelin sheath that envelops nerve fibers located in the brain and spinal cord.
Oligodendrocytes
neurons with myelin-wrapped axons
myelinated fibers
gaps between adjacent Schwann cells
Nodes of Ranvier
The outer wrapped layer of a Schwann cell
neurilemma
a group of peripheral nerve fibers (axons) bundled together like the strands of a cable
nerve
groups of wrapped axons
fasicles
covers the whole nerve
epineurium
___ form the white matter of the brain and spinal cord
tracts
brain and spinal cord tissue composed of cell bodies and unmyelinated axons and dendrites
grey matter
nerve impulses
action potentials
basic type of neuron pathway
reflex arc
two-neuron arc consists of which neurons?
sensory and motor
three-neuron arcs consist of what neurons?
sensory, interneurons, and motor
a three-neuron arc reaction
withdrawal reflex
a group of nerve-cell bodies located in the PNS
ganglion
excitatory or inhibitory; regulates parasympathetic effectors; involved in memory
Acetylcholine (ACh)
Excitatory or inhibitory; regulates sympathetic effectors, involved in emotional responses
Norepinephrine (NE)
mostly inhibitory; regulates motor control; involved in emotions and moods
Dopamine
Mostly inhibitory; involved in sleep, emotions, and moods
serotonin
mostly inhibitory; involved in blocking pain
endorphins and enkephalins
signal from presynaptic to postsynaptic neuron
nitric oxide (NO)
What are the 4 major divisions of the brain
#1 brainstem #2 cerebellum #3 diencephalon #4 cerebrum
What are the 3 divisions the brainstem consists of
#1 medulla oblongata #2 pons #3 midbrain
What are the 3 divisions the Diencephalon consists of
#1 Hypothalamus #2 Thalamus #3 Pineal Gland
In the brainstem, small bits of gray matter mix closely and intricately with white matter to form the ___
reticular formation
What are the 4 functions of the Thalamus
#1 relays sensory information #2 associates sensations with emotions #3 regulates level of consciousness #4 participates in motor reflexes
(know) the outside of the cerebrum contains ridges called Convolutions or Gyri and groves called Sulci
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islands of grey matter whose functioning is essential for producing automatic movements and postures
basal nuclei or basal ganglia
Two-way conduction pathway between the spinal cord and higher brain centers; cardiac, respiratory, and vasomotor control center
Medulla oblongata
Two-way conduction pathway between areas of the brain and other regions of the body; influences respiration
Pons
Two-way conduction pathway; relay for visual and auditory impulses
Midbrain
Muscle coordination; maintenance of equilibrium and posture
cerebellum
regulation of body temperature, water balance, sleep-cycle control, appetite, and sexual arousal
hypothalamus
sensory relay station from various body areas to cerebral cortex; emotions and alerting or arousal mechanisms
thalamus
adjusts output of melatonin in response to changes in external light, to keep the body’s internal clock on time
pineal gland
sensory perception, emotions, willed movements, consciousness, and memory
cerebrum
conducts impulses up the spinal cord to the brain
ascending tract
conducts impulses down the spinal cord from the brain
descending tracts
tough, fluid-cushioned set of membranes
meninges
What are the 3 layers of spinal meninges
#1 dura mater (outer) #2 pia mater (inner) #3 arachnoid mater (between dura and pia)
fluid fills the subarachnoid spaces between the pia mater and arachnoid in the brain and spinal cord. This fluid is called ___
Cerebrospinal fluid (CSF)
CSF forms continually from fluid filtering out of the blood in a network of brain capillaries known as the ___ and into the ventricles
Choroid plexus
Conducts impulses from nose to brain. Main function: sense of smell
olfactory
conducts impulses from eye to brain. Main function: vision
optic
Conducts impulses from brain to eye muscles. Main function: eye movements
oculomotor
Conducts impulses from brain to external eye muscles. Main function: eye movements
trochlear and abducens
conducts impulses from skin and mucous membrane of head and from teeth to brain; also from brain to chewing muscles. Main function: sensations of face, scalp, and teeth; chewing movements.
trigeminal
Conducts impulses from taste buds of tongue to brain; from brain to face muscles. Main function: sense of taste; contraction of muscles of facial expression
facial
conducts impulses from ear to brain. Main function: hearing; sense of balance
vestibulocochlear
conducts impulses from throat and taste buds of tongue to brain; also from brain to throat muscles and salivary glands. Main functions: sensations of throat, taste, swallowing movements, secretion of saliva
glossopharyngeal
Conducts impulses from throat, larynx, and organs in thoracic and abdominal cavities to brain; also from brain to muscles of throat and to organs in thoracic and abdominal cavities. Main functions: sensations of throat and larynx and of thoracic and abdominal organs; swallowing, voice production, slowing of heartbeat, acceleration of peristalsis (gut movements)
vagus
conducts impulses from brain to certain shoulder and neck muscles. Main functions: shoulder movements; turning movements of head
accessory
conducts impulses from brain to muscles of tongue. Main function: tongue movements
hypoglossal
(know) nerve impulses are also called actin potentials because each one is a difference in charge (called electrical potential) that usually triggers an action by the cell— in this case, transmission of the impulse itself. If the traveling impulse encounters a section of membrane covered with insulating myelin, it simply jumps around the myelin to the next gap in the myelin sheath. Called saltatory conduction, this type of impulse travel is much faster than is possible in nonmyelinated sections
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located in several areas of CNS; PNS neuromuscular junction; ANS and visceral effectors
acetylcholine (ACh)
Located in several areas of the CNS; sympathetic division of the ANS
Norepinephrine (NE)
Located in the brain; ANS
dopamine
located in several areas of the CNS
serotonin
located in several areas of the CNS; retina; intestinal tract
endorphins and enkephalins
located in several regions of the nervous system
nitric oxide (NO)
the brainstem consists of : (3)
midbrain, pons, medulla
(know) functions of the cerebellum are to produce smooth coordinated movements, maintain equilibrium, and sustain normal postures
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(know) the hypothalamus is involved in the regulation of water balance, sleep cycles, and the control of appetite and many emotions involved in pleasure, fear, anger, sexual arousal, and pain
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(know) the pineal gland receives sensory information about the strength of light seen by the eyes and adjusts its output of the hormone melatonin.
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(know) melatonin is known as the “time keeping hormone” because it helps to keep the body’s clock “one time” with the daily, month, and seasonal cycles of sunlight and moonlight
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(know) major cerebral functions are consciousness, thinking, memory, sensations, emotions, and willed movements.
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