Nervous System Flashcards
the __________ function is rapid communication by electrical and chemical signals
nervous system
it functions for coordination (integration) of many activities through the conduction of impulses from the receptors (sensory input - afferent) to the effectors (motor output - efferent)
nervous system
it helps maintain homeostasis and mental activity including consciousness, thinking, memory, and emotions
nervous system
what are the five functions of the nervous system
receiving sensory input
integrating information
controlling motor output
establishing and maintaining mental activity
maintaining homeostasis
sensory input
afferent
motor output
efferent
explain how the efferent and afferent work
sensory receptor —[sensory input]—> brain and spinal cord (CNS - Integration) —[motor output] PNS—> effector cells
what are the functional units of the nervous system
neurons or nerve cells
it is a cell that communicates either with one another or with muscles and glands
neurons or nerve cells
a neuron sends messages by conveying a __________
these signals result from the movement of charged ions across the cell membrane
neural impulse
part of the neuron that is the enlarged and rounded part that contains the nucleus, mitochondria that supply ATP, ribosomes that manufacture protein, and other organelles
cell body
parts of the neuron that are short, branched extensions that transmit information toward the cell body
dendrites
the number of dendrites may range from one to thousands, and each can __________ __________ from many other neurons
receive input
part of the neuron that is also called the nerve fiber, conducts nerve impulses away from the cell body
it is a long extension that is finely branched at its tip
axon
the __________, composed of fatty material, coats sections of the axon speeding up nerve impulse conduction
myelin sheath
these are gaps in the myelin sheath coating on the neural axon
nodes of ranvier
it is the propagation of neural impulse along myelinated axons from one node of ranvier to the next node, increasing the conduction velocity of the neural impulses
saltatory conduction
what are the major supporting cells in the nervous system
these cells help hold the nervous tissues together
neuroglia/neuroglial cells
neuroglial cells that are located at the brain and spinal cord, star shaped cells containing microfilaments giving them considerable strength to support neurons
astrocytes
processes of __________ wrapped around capillaries isolate the neurons from various potentially harmful substances in the blood maintaining selective permeability
astrocytes
neuroglial cells that are located at the brain and spinal cord, these cells function as phagocytes, removing microbes and damaged nervous tissues
microglia
neuroglial cells that line the brain ventricles and central canal of the spinal cord
produce and assist in the circulation of CSF
ependymal cells
the __________ protects and nourishes the brain and spinal cord
cerebrospinal fluid
neuroglial cells that are responsible for forming and maintaining the myelin sheath around the neural axons of the brain and spinal cord
a single __________ myelinate several axons
oligodendrocytes
neuroglial cells that form the myelin sheath around the axons of nerves outside the brain and spinal cord
several __________ myelinate a single axon
schwann cells
neuroglial cells that are flat and surround the cell bodies of neurons outside the brain and spinal cord providing structural support
satellite cells
neuroglial cells that regulate exchanges of materials between cell bodies and the interstitial fluid
satellite cells
the ability of a neuron to respond to a stimulus and convert it to a nerve impulse
irritability
the transmission of a nerve impulse along a neuron from one end to the other occurs as a result of electrical changes across the membrane of the neuron
irritability
also known as a nerve impulse or nerve signals, a pulse like wave of voltage that passes on through a neuron that influences other neurons
action potentials
the ability of the neuron to transmit the impulse to other neurons, muscles, or glands
conductivity
when a nerve impulse reaches the end of an axon, the axon releases chemicals called __________ stored at its synaptic vesicles
neurotransmitters
a __________ is a specialized junction at which a signal from one neuron’s axon flows with another neuron or an effector organ such as muscle or gland
chemical synapse
part of the synapse that is the space between 2 communicating nerve cells
synaptic cleft
part of the synapse that consists of the end of an axon
presynaptic terminal
part of the synapse that contains many small sacs, or vesicles, that hold neurotransmitter molecules
presynaptic terminal
part of the synapse that is the receptor containing membrane of the postsynaptic cell opposed to the presynaptic terminal
postsynaptic membrane
__________ cells are typically other neurons, muscles, or glands
postsynaptic cells
chemical signals that travel from a “sending” cell to a “receiving” cell
these substances may be excitatory or inhibitory
neurotransmitters
nervous tissue that consists of neuron cell bodies and dendrites, along with the synapses by which they communicate with other cells
information processing occurs in the __________
gray matter
nervous tissue that consists of myelinated axons transmitting information throughout the nervous system
white matter
nervous tissue that forms the nerve tracts or conduction pathways of the brain and spinal cord which propagate impulses
white matter
outside the brain and spinal cord, the bundles of axons and their connective tissue sheaths are called __________
nerves
which of the two nervous tissues is more important
gray matter
contains the brain and spinal cord
central nervous system
contains the 12 cranial nerves and the 31 spinal nerves
peripheral nervous system
division of the PNS that communicates with internal organs and glands
autonomic nervous system
division of the PNS that communicates with sense organs and voluntary muscles
somatic nervous system
division of the autonomic nervous system that is responsible for arousing and fight or flight
also called as E division or emergency division
sympathetic division
division of the autonomic nervous system that is responsible for calming, rest or digest, or feed or breed
also called as D division or defecation division
parasympathetic division
the __________ consists of the brain and spinal cord, which act as the integrating and command centers of the nervous system
central nervous system
the __________ is the largest and the most complex mass of nerve tissue in the body
it functions to exert centralized control over the other organs of the body
brain
the __________ acts on the rest of the body both by generating patterns of muscle activity and by driving the secretion of chemicals called hormones
brain
what are the three brain subdivisions
forebrain
midbrain
hindbrain
it is the largest part of the hindbrain
its neurons refine motor messages and coordinate muscle movements for posture and balance subconsciously
cerebellum
region of the hindbrain that is the pathway for ascending and descending nerve tracts
medulla oblongata
this region not only regulates blood vessel diameter, breathing, blood pressure, and heart rate, but it also contains reflex centers for vomiting, coughing, sneezing, defecating, swallowing, and hiccupping
medulla oblongata
part of the hindbrain which means “bridge”, connects the forebrain with medulla oblongata and cerebellum enabling relaying of information
pons
it is made up of the midbrain and parts of the hindbrain (medulla oblongata and pons)
brainstem
it is part of the midbrain that is a stalk-like lower portion of the brain that regulates essential survival functions such as breathing and heartbeat
it connects the spinal cord to the brain
brainstem
it is nuclei scattered throughout the brainstem; controls brainstem activities, including motor control, pain perception, rhythmic activities, and the sleep wake cycle (Circadian rhythm)
reticular formation
part of the forebrain that controls the activities of the lower parts of the brain
cerebrum
it contains the cortex enabling it to perform higher functions like interpreting touch, vision and hearing, as well as speech, reasoning, emotions, learning, and fine control of movement
cerebrum
it controls the qualities of what we consider the “mind” that is personality, intelligence, learning, perception, and emotion
cerebrum
it connects the brainstem to the cerebrum; has many relay and homeostatic functions
diencephalon
they are the elevated ridges in the cerebrum
gyri (gyrus)
they are the shallow grooves in the cerebrum
sulci (sulcus)
what are the two hemispheres of the cerebrum that gather and process information
left hemisphere and right hemisphere
what is the most important brain subdivision and why is it important
hindbrain; controls the respiratory centers
which hemisphere is responsible for speech, language skills, mathematical ability, and reasoning
left hemisphere
which hemisphere is responsible for spatial, intuitive, musical, and artistic abilities
right hemisphere
each hemisphere controls the opposite side of the body
decussation
it is a very large fiber tract the connects the cerebral hemispheres
corpus callosum
the cerebral hemispheres work together, interconnected by a thick band of nerve fibers called the __________ __________
corpus callosum
what are the three parts of the cerebrum
cerebral cortex
limbic system
basal nuclei
it is the outer layer of the cerebrum that consists of gray matter that processes information
cerebral cortex
lobe responsible for the primary motor area that allows the conscious movement of the skeletal muscles
frontal lobe
lobe where the body’s sensory receptors are localized and interpreted
it allows recognition of pain, coldness, and light touch
parietal lobe
the auditory and olfactory lobe
temporal lobe
the visual area lobe
occipital lobe
part of the diencephalon that is a mass of gray matter located between the midbrain and cerebrum
it also influences mood and movement
thalamus
this central relay station processes incoming sensory information and sends it to the appropriate part of the cerebrum
thalamus
small area inferior to the thalamus
it contains nerve tracts and nuclei
subthalamus
the __________ __________ are associated with the basal ganglia and are involved in controlling motor functions
subthalamic nuclei
small area superior and posterior to the thalamus
it contains nuclei responding to olfactory stimulation and contains the pineal gland for sleep wake cycle and other biorhythms
epithalamus
the pineal gland secretes __________ that regulates RAS (sleep-wake cycle)
melatonin
neural and hormonal signals from the ___________ regulate body temperature, heartbeat, water balance, blood pressure, along with hunger, thirst, sleep, and sexual arousal
hypothalamus
this part of the diencephalon functions for mood, motivation, and emotion
it also interacts with the reticular activating system coordinating the sleep wake cycle
hypothalamus
it is the major communication link between the brain and the peripheral nervous system to the head
it integrates incoming information and produces responses through the reflex mechanisms
spinal cord
the spinal cord tapers to form a cone like region called the __________ __________
conus medullaris
the numerous roots of spinal nerves extending from the conus medullaris resemble a horse’s tail and is called the __________ __________
cauda equina
the spinal cord __________ __________ consists of neuron cell bodies, dendrites, and unmyelinated axons
gray matter
the __________ gray horns contain somatic motor nuclei, which are clusters of cell bodies of somatic motor neurons that provide nerve impulses for contraction of skeletal muscles
ventral
the __________ gray horns contain cell bodies and axons of interneurons as well as axons of incoming sensory neurons
dorsal
the __________ gray horns contain autonomic motor nuclei, which are clusters of cell bodies of autonomic motor neurons that regulate the activity of cardiac muscle, smooth muscle, and glands
lateral
the spinal cord __________ __________ consists of myelinated axons, which form nerve tracts
white matter
the __________ columns carry both ascending information about pain and temperature, and descending motor information
ventral
the __________ columns carry ascending sensory information from somatic mechanoreceptors
dorsal
the __________ columns include axons that travel from the cerebral cortex to contact spinal motor neurons
these pathways are also referred to as the cortico-spinal tracts
lateral
the __________ are layered membranes that jacket the central nervous system
meninges
what are the three layers of the meninges (from superficial to deep)
dura mater
arachnoid mater
pia mater
innermost membrane, closely adhering to the surface of the brain and spinal cord; well supplied with blood vessels that carry food and oxygen
pia mater
middle membrane, made up of fibrous and elastic connective tissues; separated to the pia mater by the cerebrospinal fluid
arachnoid mater
the interval between the arachnoid mater and the pia mater
it is occupied by delicate connective tissue and the intercommunicating channels containing cerebrospinal fluid
subarachnoid space
outermost membrane; thick and tough linings
dura mater
it is a hollow tube or cavity formed by the CNS
the brain and the spinal cord contain fluid filled cavities
ventricles
the __________ are a communicating network of cavities that produce and is filled with CSF
ventricles
large cavity in each cerebral hemisphere, 1st and 2nd ventricles
lateral ventricles
a smaller midline cavity of the diencephalon between two halves of the thalamus
third ventricle
inferior of the pons and superior of the medulla oblongata at the base of the cerebellum
it is continuous with the central canal of the spinal cord
fourth ventricle
it is the build up of fluid in the ventricles deep within the brain
CNS was not drained properly
hydrocephalus
it is a clear, colorless fluid found in CNS either intracerebrally in the ventricular system of the brain (making up 20%) or extracerebrally in the subarachnoid space (making up 80%)
cerebrospinal fluid
it bathes and cushions the brain and the spinal cord
this fluid insulates the CNS from injury
cerebrospinal fluid
it nourishes the brain and removes metabolites as well as regulates intracranial pressure
the total volume of __________ __________ is approximately 150 mL and it is produced at a rate of 450 mL per day
cerebrospinal fluid
the cerebrospinal fluid replaces itself __________ times a day
three times
it is a plexus of cells that produces the cerebrospinal fluid in the ventricles of the brain
it consists of modified ependymal cells
choroid plexus
80-90% of the CSF is produced by __________ __________ within the lateral ventricles, with the remainder produced by similar cells in the third and fourth ventricles
ependymal cells
the __________ lines the brain’s capillaries and helps protect the brain from harmful chemicals
it consists mainly of tight junctions that seal together the endothelial cells of brain blood capillaries and a thick basement membrane that surrounds the capillaries
blood-brain barrier
it is a beta blocker that lowers heart rate and prevents tremors and migraines
propranolol
the ___________ consists of all nervous tissue outside the CNS
peripheral nervous system
it includes nerves (cranial and spinal), sensory receptors, ganglion (collection of neuron cell bodies and clusters of gray matter outside the CNS that act as relay stations) and plexus (a branching network of intersecting afferent and efferent nerves outside the CNS innervating the same are of the body for sensory and motor functions)
peripheral nervous system
it is an enclosed cable like bundles of axon nerve fibers and their sheaths (Schwann cells) in the PNS
nerve
it connects the CNS to sensory receptors, muscles and glands
it provides a common pathway for the electrochemical nerve impulses
nerve
each axon in the PNS within the nerve is an extension of an individual neuron along with other supportive cells such as the __________ that coats the myelin sheat
Schwann cells
what are the three connective tissue layers of the nerve
endoneurium
perineurium
epineurium
these nerves emerge directly from the brain an carry impulses to and from the brain
cranial nerves
these nerves control movements of the eyes, face, neck, and mouth along with the senses of taste and hearing
they have sensory, somatic motor, and autonomic motor functions
cranial nerves
spinal nerves from C1 to C4 innervating superficial neck structures and muscles, skin of the neck and posterior portion of the head
cervical plexus
spinal nerves from C5 to T1 supply the skin and muscles of the body’s upper limbs
brachial plexus
overlapping spinal nerves of the __________ from L1 to L4 and __________ from L4 to S4, supplying the skin and musculature of the lower limb
lumbar plexus
sacral plexus
from spinal nerve S5 and coccygeal nerve, supplying motor innervation to the muscles of the pelvic floor and sensory innervation of the skin over the coccyx
for bladder and bowel control of muscles, external genitalia sensation
coccygeal plexus
spinal nerves responsible for head movement and diaphragm movement
C1 to C4
spinal nerves responsible for neck and shoulder movement
C4 to C6
spinal nerves responsible for upper limb movement
C5 to T2
spinal nerves responsible for rib movement in breathing, vertebral column movement, and tone in postural back muscles
T1 to T12
spinal nerves responsible for hip movement
T11 to L3
spinal nerves responsible for lower limb movement
L2 to S3
these nerves are the paths of communication between the spinal cord and specific regions of the body
they carry impulses to and from the spinal cord to the appropriate glands or muscles
spinal nerves
the __________ of the spinal nerve contains outgoing, efferent fibers that carry information destined to control motor or glandular function
ventral root
the __________ of the spinal nerve contains incoming, afferent fibers that carry sensory information from the sensory receptors
dorsal root
a cluster of sensory neuron cell bodies function as a relay station located at the dorsal root of a spinal nerve
dorsal root ganglion or spinal ganglion
how many pairs of spinal nerves are there
31 pairs
enumerate all the spinal nerves
cervical nerves - 8 pairs
thoracic nerves - 12 pairs
lumbar nerves - 5 pairs
sacral nerves - 5 pairs
coccygeal nerves - 1 pair
the __________ division consists of nerve fibers that convey impulses to the central nervous system from sensory receptors located in various parts of the body
sensory or afferent division
the __________ division carries impulses from the CNS to the effector organs, the muscles and glands
motor or efferent division
the __________ allows conscious or voluntary control on skeletal muscles; otherwise known as the voluntary nervous system
somatic nervous system
the __________ regulates events that are automatic or involuntary, such as the activity of the smooth and cardiac muscles and glands
autonomic nervous system
otherwise known as the involuntary nervous system
it is responsible for the control of visceral functions: cardiovascular, respiratory, digestive, urinary, reproductive, and response to stress
autonomic nervous system
what are the two efferent divisions
somatic and autonomic nervous system
what are the two divisions of the autonomic nervous system
sympathetic and parasympathetic nervous system
the __________ is activated during stress and emergencies
neurons of the __________ slow digestion and boost blood flow toward vital organs like the heart, brain, and muscles necessary for “fight or flight”
sympathetic nervous system
the __________ returns body systems to normal; heart rate and respiration slow and digestion resumes for “rest and digest”
parasympathetic nervous system
what is the largest nerve in the body
sciatic nerve
