Nervous System Flashcards
The nervous system is responsible for controlling most body functions, enabling organisms to ___ and ___ to stimuli from their ___ and ___ environments
receive, respond, external, internal
Signals from the nervous system travel ____, reaching in excess of ______m/s, and in some cases, which results in transmission of information much more rapidly than through the ___ ____
quickly, 100, endocrine system
The nervous system is composed of both ___ and ____. These cells work together to form the major organs of the nervous system, which include the ___ and ___ ____, as well as complex sensory organs such as the ___ and ____. In turn these organs can be grouped into the ____ and ____.
neurons, neuroglia, brain, spinal cord, eye, ear, PNS, CNS
Myelin is produced by glial cells known as ___ in the CNS and by ___ _____ in the PNS.
oligodendrocytes, schwann cells
Maintain the integrity of BBB, regulate nutrient and dissolved gas concentrations, absorb and recycle neurotransmitters
astrocytes
myelinate CNS axons as well as provide structural framework for the CNS
oligodendrocytes
remove cellular debris and pathogens
microglia
line the brain ventricles and aid in the production, circulation and monitoring of CSF
ependymal cells
Surround the neuron cell bodies in the ganglia
satellite cells
enclose axons in the PNS and aid in the myelination of some peripheral axons
schwann cells
The Na/K+ pump pumps ___ Na+ ____ of the cell for every ___ K+ it transports ___ to the cell. This uneven exchange results in a ____ _____ environment. Furthermore, the cell membrane is more permeable to ___ than to ____. This allows some of the K+ that was pumped into the cell to move back out through ___ ___, making the internal environment even more negative
3, out, 2, into, negative, internal, K+, Na+, facilitated diffusion
When depolarization reaches the ____ ___, then ___ ___ __ located into the nerve cell membrane open and an ___ ___ begins when ____ rushes into the cell. This causes the next portion of the ___ toward the terminal to be depolarized and so on until it reaches the ___ ___. At the terminal, a final _____ ____ ____ is opened and __ triggers the ___ of synaptic vesicles containing neurotransmitters
threshold potential, voltage-gated ion channels, action potential, Na+, axon, synaptic terminal, voltage-gated Ca channel, Ca2+, exocytosis
After the signal has been propagated through a segment of the axon, the high voltage there causes ______ ___ ___ to open, allowing K+ to flow ___ of the cell. Meanwhile, the voltage gated Na+ channels _____, and the Na+/K+ pump begins to pump Na+ ___ again. This is called ____.
voltage-gated K+ channels, out, close, out, repolarization
The neuron’s voltage shoots past the ___ __ and becomes even more negative inside than normal due to the K+ still being free to ___ the cell. This is called ______. this results in a ___ ____, where new APs cannot be generated. This period allows the neuron time to _____ ____ and also helps ensure the action potential only moves in the ___ direction, towards the terminal
resting potential, leave, hyperpolarization, refractory period, regenerate neurotransmitter, forward
The action potential itself can be described as an ______ response. The stimulus intensity is coded by the ___ of the action potentials and not by their ____
all-or-none, frequency, magnitude
The greater the ___ of the axon, and the more heavily it is ___, the faster the impulses travel. Myelin increases the __ ___ by insulating segments of the axon such that the membrane is permeable to ___ only in the ___ ___ ___. In this way, the action potential ___ from node to node
diameter, myelinated, conduction velocity, ions, nodes of ranvier, hops
Neurons that communicate with cells in muscles or glands
effector cells
Neurotransmitter can undergo ____ by ______ ____, where it may be reused or degraded, it may be degraded by ___ located in the synapse, or it may simply ____ out of the synapse
reuptake, uptake carriers, enzymes, diffuse
Drug that blocks the postsynaptic nicotinic ACh receptors such as those on muscles, leading to muscle relaxation and paralysis by blocking the ability to constrict muscles
curare
Drug that prevents the release of ACh from the presynaptic membrane and also results in paralysis
botulinum toxin
drugs used as nerve gases and in the insecticide parathion; inhibit the activity of ACh enzyme respomnsible for degrading ACh released in synapse; results in no coordinated muscular contractions
anticholinesterases
neurons that carry sensory information about the external or internal environment to the brain and spinal cord
afferent neurons
neurons that carry motor commands from the brain or spinal cord to various parts of the body
efferent neurons
neurons that participate only in local circuits, linking sensory and motor neurons in the brain and spinal cord; cell bodies and nerve terminals are in the same location
interneurons
bundles of axons covered with connective tissue
nerves
plexus
network of nerve fibers
clusters of neuronal cell bodies in the periphery
ganglia
clusters of neuronal cell bodies in the CNS
nuclei
The brain’s functions including interpreting __ ___, forming __ ___, and __ ___. The brain consists of an outer portion of cell bodies called the ___ ___ and an inner portion of myelinated axons called the ___ __.
sensory information, motor plans, cognitive function, grey matter, white matter
The forebrain or ____, consists of the ___ and ____.
prosencephalon, telencephalon, diencephalon
A major component of the telencephalon is the __ __, which is the highly convoluted ___ ___ that can be seen on the ___ of the brain. The cortex processes and _____ sensory inputs and motor responses and is important for __ and ___ thought. The ___ ___ is the center for reception and integration of olfactory input
cerebral cortex, grey matter, surface, integrates, memory, creative, olfactory bulb
The diencephalon contains the __ and ____. The former is a relay and _____ center for the spinal cord and __ ____. The latter controls ____ functions such as hunger, thirst, __ __, water balance, ____ ___ and ____ regulation. It also plays an important role in the control of the ___ system
thalamus, hypothalamus, integration, cerebral cortex, visceral, sex drive, blood pressure, temperature, endocrine
The midbrain or the _____ is a relay center for visual and ___ impulses, It also plays an important role in ___ control
mesencephalon, auditory, motor
The hindbrain or the ____ is the posterior part of the brain and consists of the ___, ___, and ____.
cerebellum, pons, medulla
Helps to modulate motor impulses initiated by the cerebral cortex and is important in the maintenance of balance, hand-eye coordination, and the timing of rapid movements
cerebellum
Acts as a relay center to allow the cortex to communicate with the cerebellum
pons
controls vital functions like breathing, heart rate, and gastrointestinal activity
medulla
The midbrain pons and medulla
brainstem
The spinal cord is an elongated extension of the brain that acts as the ____ for sensory information to the brain and ___ information from the brain. The spinal cord can integrate ___ motor responses such as ___ by itself.
channel, motor, simple, reflexes
A cross section of the spinal cord reveals an outer __ ___ area containing motor and ___ ____, and an inner gray matter area containing __ ___ bodies.
white matter, sensory axons, nerve cell
Sensory information enters the spinal cord through the ___ ___. The cell bodies of those sensory neurons are located in the __ ___ ______. All motor information exist the spinal cord through the __ ___. For simple reflexes like the ____ reflex, sensory fibers synpase direct on ___ ___ ___ ____. Other reflexes include ___ between the sensory and motor fibers that allow for some processing in the spinal cord
dorsal horn, dorsal root ganglia, ventral horn, knee-jerk, ventral horn motor fibers, interneurons
The somatic nervous system innervates ___ __ and is responsible for __ __ as well as __ ___ (pathways that control motor reflexes)
skeletal muscles, voluntary movement, reflex arcs
The autonomic nervous system, aka the __ ___ ___, regulates the body’s ___ _____ without the aid of conscious control. The autonomic innervation of the body includes both ___ and __ fibers.
involuntary nervous system, internal environment, sensory, motor
The ANS innervates __ and ___ muscle. The latter is located in areas like the __ ___, the ___ __, bladder, and ____, so the ANS is important in ___ ___ control, ___ ____, _____, respiration and reproduction.
cardiac, smooth, digestive tract, blood vessels, bronchi, blood pressure, gastrointestinal motility, excretion
The _____ division of the ANS readies the body for action in an emergency situation; increases blood pressure and ___ ____, increases blood flow to skeletal muscles and decreases gut motility. Dilates _____ to increase gas exchange, uses ____ as its primary neurotransmitter
sympathetic, heart rate, bronchioles, norepinephrine
The _____ division of the ANS acts to conserve energy and restore the body to __ ___ levels after exertion. It acts to lower heart rate and increase ___ __. The ____ ___ is a parasympathetic nerve that innervates many of the __ and __ ____. It uses ___ as its primary neurotransmitter
parasympathetic, resting activity, gut motility, vagus nerve, thoracic, abdominal, acetylcholine
A thick, opaque layer covering the eye which is also known as the white of the eye.
sclera
underneath the sclera, helps supply retina with blood and reduces reflection in the eye
choroid layer
Innermost layer of the eye
retina
cells in the retina that sense light
photoreceptors
in front of the light; bends and focuses light rays
cornea
opening in the eye behind the cornea
pupil
pigmented muscular part of the eye that controls pupil dilation by responding to light
iris
behind the pupil; focuses the images onto the retina
lens
controls the shape and focal length of the lens
cillary muscles
Photoreceptors transduce light into ____ ___. _____ respond to high intensity lumination and are sensitive to ___. ____ detect low intensity lumination and are important in ___ ___. Both contain various ___ that absorb specific ____ of light. Cones contain __ pigments that absorb __, ___ and ___ wavelengths. _____, the rod pigment, only absorbs a ____ wavelength.
action potentials, Cones, colour, rods, night vision, pigments, wavelength, 3, red, green, blue, rhodpsin, single
Axons of the ganglion cells bundle to form the ___ ___, which conducts visual information to the brain. The point at which the optic nerve exists the eye is called the ___ __ because ___ are not present there.
optic nerve, blind spot, photoreceptors
A small area above the blind spot densely packed with cones and important for high-acuity vision
fovea
a jelly like material that helps the eye maintain its shape and optical properties
vitreous humor
a more watery substance that fills the space between the lens and the cornea
aqueous humor
occurs when the image is focused in front of the retina
nearsightedness/myopia
occurs when the image is focused behind the retina
hyperopia /farsightedness
caused by an irregularly shaped cornea
astigmatism
develop when the lens becomes opaque and light cannot enter the eye; blindness results
cataracts
an increase in the pressure in the eye because of blocking of the outflow of the aqueous humor, which results in optic nerve damage
glaucoma
The ear transduces energy ___ ____ into impulses perceived by the brain as sound. Sound waves pass through __ regions as they enter the ear.
pressure waves, 3
First, sound waves enter the ___ ___ which consists of the ___ (external ear) and the __ ___. At the end of the auditory canal is the __ ___ (eardrum) of the middle ear, which vibrates at the same ___ of the incoming sound. Next, the ____, (___, ___ and _____) of the middle ear amplify the stimulus and transmit it through the ___ ___. This leads to the ___ ___ inner ear.
outer ear, auricle, auditory canal, tympanic membrane, frequency, ossicles, malleus, incus, stapes, oval window, fluid filled
The inner ear consists of the ___ and the ___ ___, which is involved in maintaining equilibrium. Vibration of the ossicles exerts pressure on the fluid in the ____, stimulating ___ ___ in the __ ___ to transduce the pressure into action potentials, which travel via the ____ ____ to the brain for processing
cochlea, vestibular apparatus, cochlea, hair cells, basilar membrane, cochlear nerve
