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Brain anatomy
Nervous system
222
Physiology
Undergraduate 1
11/25/2014

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Term
Ganglia
Definition
collection of neuron cell bodies found in peripheral nervous system
Term
nucleus
Definition
collection of neuron cell bodies with a common function found in central nervous system
Term
what are the 3 basic components of a homeostatic system?
Definition
receptor, control center or integration center, effector
Term
negative feedback
Definition
receptor stimulation stimulates a response that changes the environment at the receptor. An effector negates the original stimulus
Term
positive feedback
Definition
an initial stiumuls produces a response that exagggerates or enhances the change in the original conditions
Term
how is the nervous system organized?
Definition
[image]
Term
what is the role of a neuron?
Definition
transfer impulses from place to place and process information
Term
what is the role of neuroglia?
Definition
maintain physical structure of nural tissue, repair neural tissue framework after injury, perform phagocytosis, provide nutrients to neurons, regulate the composition of the interstitial fluid surrounding neurons. - most abundant
Term
what are the 6 types of neuroglial cells?
Definition
1. Oligodendrocytes
2. ependymal cells
3. microglia
4. astrocytes
5. schwann cells
6. satellite cells
Term
oligodendrocytes
Definition
form myelin in brain and spinal cord
Term
ependymal cells
Definition
line cavities of brain and spinal cord; secrete and circulate cerebrospinal fluid
Term
microglia
Definition
phagocytize and destroy microorganisms, foreign matter, and dead nervous tissue
Term
astrocytes
Definition
maintain the blood-brain barrier, provide structural support withing reural tissue, regulate ion, nutrient, and gas concentrations
Term
schwann cells
Definition
form a sheath around peripheral axons, from neurilemma around all PNS nerve fibers and myelin around most of them; aid in regeneration of damaged nerve fibers
Term
satellite cells
Definition
surround somas of neurons in the ganglia, rovide electrical insulation and regulate environment of neurons.
Term
what are the 3 physiological properties of neurons that allow them to communicate with other cells?
Definition
1. excitability- polarized and able to reverse polarity
2. conductivity- ability for excitement (reversal of polarity) to move along the membrane
3. secretion- ability to secrete neurotransmitters into and across synapse.
Term
what are the 3 functional classes of neurons and where are they found?
Definition
1. sensory neurons- UNIPOLAR neurons whose cell bodies are located in the PNS. Some somatic sensory, some visceral sensory, send to CNS.
2. Interneurons- completely within CNS- from one cell to another (association)
3. motor neurons- conduct impulses from CNS to muscle or gland - PNS EFFERENT
Term
what is the most abundant functional neuron in the body?
Definition
Interneurons
Term
what does a typical multipolar neuron look like?
Definition
[image]
Term
what is the myelin sheath?
Definition
the outer layer of the schwann cell
Term
what is perikaryon?
Definition
the cytoplasm surrounding the nucleus.
Term
what is a neurofibril?
Definition
bundles of neurofilaments that extend into the dentrites and axon, providing internal support-manufacture cytoskeleton parts and proteins
Term
what part of the neuron binds to neurotransmitters?
Definition
cell bodies and dendrites
Term
what kind of cell produces myelin in the CNS?
Definition
oligodendrocytes- processes of oligodendrocytes wrap many different axons
Term
what kind of cell produces myelin in the PNS?
Definition
Schwann cells- cell envelopes axon, continues wrapping around
Term
what are the 3 other main structural classes of neurons besides multipolar?
Definition
anaxonic (no axons, only dendrites)
unipolar, bipolar.
Term
relate the 3 structural groupings to the 3 functional groupings: sensory, association, and motor.
Definition
sensory- bipolar, unipolar (all of somatic sensory, most of visceral)
sensory, interneurons, motor- multipolar
Term
what are the 3 classes of sensory receptors?
Definition
exteroceptors- sense stimuli external to body
interoceptors- stimuli inside the body
proprioceptors- sense potision and movements of body or its parts.
Term
ID 5 classes of sensory receptors based on sensitivity
Definition
Thermoreceptors
Photoreceptors
Nociceptors
Chemoreceptors
Mechanoreceptors
Term
Nociceptors
Definition
pain receptors- sense tissue injury or situations that threaten to damage tissue
Term
chemoreceptors-
Definition
respond to chemicals- odors, tatstes, bodily fluid composition
Term
mechanoreceptors
Definition
respond to stimuli that distorts their plasma membranes caused by vibration, touch, pressure, stretch, or tension. Hearing, balance, skin, viscera, joints.
Term
what are the 4 kinds of info transmitted by sensory receptors?
Definition
1. modality- brain can ID basic type of info
2. location- whwere the info is coming from
3. intensity- determined by how many receptors are sending info and how fast messages are being received
4. duration- if messages keep coming from same receptros, stimuli is ongoing.
Term
what is meant by the term adaptation in regard to a receptor?
Definition
a reduction in sensitivity in the presence of a constant stimulus. (if no response to message receptor sends, the receptors will send messages more slowly)
Term
what is somatic pain?
Definition
comes from the skin and deep tissues- the brain can accurately assess the pain source.
Term
what is visceral pain?
Definition
comes from internal organs and/or blood vessels- brain is unable to determine precise location.
Term
what is referred pain?
Definition
the sensation of pain in a part of the body other than its actual source. visceral pain that the brain thinks is on the surface of the body.
Term
what is phantom pain?
Definition
an axon whose receptor has been severed (amputation) can still fire messages to CNS if stimulated enough.
Term
what are the 5 primary taste sensations?
Definition
Salty, sweet, bitter, sour, and umami (amino acids like aspartic and glutamic acids
Term
what cell structure is adapted both for sensing stimulation and for initiating and conducting the nerve impulse?
Definition
Cell membrane aka phospholipid bilayer
Term
what is membrane potential?
Definition
the actual measured difference in electrical charge between the outside and inside of a nerve cell membrane.
Term
what is resting potential, and what is the average value for a resting potential?
Definition
the membrane potential present in a nerve cell which is resting (not undergoing an action potential or nerve impulse) Average value is -70 Millivolts.
Term
Describe the distribution of the major ions inside and outside a resting nerve cell's membrane and explain what causes this particular distribution.
Definition
more sodium (Na+) outside
-relatively few sodium channels in membrane
-sodium potassium pump pumps it out
more potassium inside
-when potassium leaks out, positive outer membrane repels it back in
-negatively charged proteins attract K
More chloride (Cl-) on outside
-no channel to allow it in
-sodium attracts
Term
Define stimulus
Definition
something which changes the membrane potential
Term
define local potential
Definition
small change in membrane potential produced by ions moving through ligand regulated or mechanically regulated gates on dendrites or cell body
Term
ligand regulated channel
Definition
one which is chemically regulated
Term
define the term threshold potential and state an average value for a threshold potential
Definition
the point at which the local (graded) depolarization at the axon hillock is large enough to open voltage-gated sodium and potassium channels
-55 mv
Term
chemical gradient
Definition
concentration gradient across the plasma membrane
Term
electrical gradient
Definition
created by the attraction between opposite charges, or the repulsion between like charges
Term
electrochemical gradient
Definition
chemical and electrical gradients combined = potential energy
Term
diagram typical action potential
Definition
[image]
Term
in which direction are positive ions diffusing during the resting phase?
Definition
into and out of the cell
Term
which ions tend to diffuse into the cell? (resting)
Definition
sodium
Term
which ions tend to diffuse out of the cell? (resting)
Definition
potassium
Term
what types of ion chnnels are being used by any diffusion that hapens during this phase? (resting)
Definition
non-gated
Term
During the change to threshold, is the inside of the membrane becoming more positive or more negative?
Definition
more positive
Term
in which direction must positive ions be diffusing FASTER than at rest? (change to threshold)
Definition
into the cell
Term
which ions must be diffusing faster than at rest? (change to threshold)
Definition
sodium
Term
which type of ion channel must have opened to trigger this change? (change to threshold)
Definition
chemically-gated (sodium specific)
Term
when diffusion (simple) is the mechanism of movement, which factor is involved in actually making the ions move? (change to threshold)
Definition
the kinetic energy of the ions themselves.
Term
During action potential, is the inside of the memrane becoming more positive or more negative?
Definition
more positive
Term
in which direction must positive ions be diffusing faster than during change to threshold? (action potential)
Definition
into the cell
Term
which ion must be diffusing faster than during change to threshold? (action potential)
Definition
sodium
Term
which type of ion channel must have opened to trigger this change? (action potential)
Definition
voltage-gated (sodium specific)
Term
during the repolarization phase, is the inside of the membrane becoming more positive or more negative?
Definition
more negative
Term
in which direction must positive ions be diffusing faster than at rest? (repolarization)
Definition
out of the cell
Term
which ion must be diffusing faster than at rest? (repolarization)
Definition
potassium
Term
which type of ion channel must have opened to trigger this change? (repolarization)
Definition
voltage-gated (potassium specific)
Term
which types of ion channels apparently return to a closed position either prior to or during this phase? (repolarization)
Definition
voltage-gated (sodium) and voltage-gated (potassium)
Term
Which type of ion channel apparently returns to a closed position to trigger after-hyperpolarization phase?
Definition
voltage-gated (sodium)
Term
which types of ion channels open during this phase? (after-hyperpolarization)
Definition
non-gated, voltage-gated potassium
Term
the membrane continues to be (relatively) refractory during this phase. how is the membrane different than it was at rest? (after-hyperpolarization)
Definition
resting potential is not quite right, some sodium that was outside the cell prior to depolarization phase is now inside, some potassium that was inside the cell prior to repolarization is now outside.
Term
what mechanism that is functional during this phase is capable of returning sodium and/or potassium distribution patterns to a normal resting state? (after-hyperpolarization)
Definition
sodium/potassium pump
Term
excitatory stimulus
Definition
any stimulus which causes the nerve cell mambrane potential to become more positive
Term
inhibitory stimulus
Definition
any stimulus which causes the nerve cell membrane potential to become more negative
Term
when an excitatory stimulus is applied to a nerve cell membrane and an action potential results, does the initial action potential occur along the entire nerve cell membrane all at once or only at the site of stimulation?
Definition
only at the site of stimulation (axon hillocks)- then the action potential at that site triggers an action potential at an adjacent site and continues along the membrane.
Term
what are 2 features of neuron anatomy that influence the speed of a nerve impulse?
Definition
presence of myelin- greatly speeds nerve impulse
diamerter of axon 0 the bigger the diameter, the faster.
Term
subtrheshold
Definition
excitatory stimulus that changes the membrane potential but not up to -55mv. (local potential only)
Term
threshold
Definition
excitatory stimulus t0 -55mv (action potential)
Term
suprathreshold
Definition
excitatory stimulus above -55mv (Action potential)
Term
gap junction
Definition
transmembrane portein tunnels connecting cytoplasm of one cell to cytoplasm of another.
Term
what is the significance of synaptic delay in terms of the speed of a given nerve circuit?
Definition
the more synapses, the slower the circuit.
Term
what is neural integration?
Definition
the ability of neurons to process, store, and recall information and make decisions.
neural integration is based on the postsynaptic potentials produced by neurotransmitters received in chemical synaptic transmission. The more synapses is has, the greater its information processing abilities.
Term
How do chemical synapses be influenced?
Definition
there is a point when everything is outside of the cell. this allows control over our responses.
Term
which neurotransmitter is associated with the excitation of skeletal muscle?
Definition
acetylcholine
Term
which neurotransmitter is associated with the excitation of cardiac muscle?
Definition
norepinephrine
Term
which neurotransmitter is associated with the inhibition of cardiac muscle?
Definition
acetylcholine
Term
what is the major excitatory transmitter in the brain?
Definition
glutamate
Term
what is the major inhibitory neurotransmitter in the brain?
Definition
gamma-aminobutyric acid (GABA)
Term
what is a neurotransmitter associated with pain transmission?
Definition
substance p
Term
2 neurotransmitters that relieve or suppress pain
Definition
enkephalins, beta endorphins
Term
what is the major excitatory transmitter in the brain?
Definition
glutamate
Term
what is the major inhibitory neurotransmitter in the brain?
Definition
gamma-aminobutyric acid (GABA)
Term
what is a neurotransmitter associated with pain transmission?
Definition
substance p
Term
2 neurotransmitters that relieve or suppress pain
Definition
enkephalins, beta endorphins
Term
what is a neuromodulator?
Definition
alters the rate of neurotransmitter release (exocytosis) changes postynaptpic cell's response to neurotransmitters.
Term
example of chemical neuromodulator
Definition
dopamine, endorphins
Term
example of gaseous neuromodulator
Definition
nitric oxide, carbon monoxide (some organic)
Term
how can a neurotransmitter have both excitatory and an inhibitory effects in some circumstances?
Definition
the effects of the neurotransmitters are determined by the receptors receiving them. IF receptor causes positive ions to be let in, excitatory. IF receptor causes negative ions to be let in, inhibitory.
Term
If you were going from the outside of the head to the surface of the brain, which layers would you pass?
Definition
epidermis, dermis, subcutaneous, connective, muscle, connective, periosteum, compact, spongy, compact, periosteum, epidural space, dura, subdural space, arachnoid, subarachnoid, pia, cerebral cortex.
Term
Central spinal fluid- location, volue, formation and reabsorption, and functions
Definition
subarachnoid space, appr. 150mL at any moment, choroid plexuses produce and maintain CSF, at a rate of about 500mL a day. Entire volume of CCSF is replaced every 8 hrs. Surrounds exposed surfaces of CNS, acts as a showck absorber and as a diffuion medium for dissolved gases, nutrients, chemical messengers, and wastes. Also BUOYANCY and protection.
Term
how is cerebrospinal fluid sampled?
Definition
lumbar puncture, aka spinal tap needle is inserted into the subarachnoid space in the lumbar region inferior to the tip of the conus medullaris.
Term
what is the conus medullaris?
Definition
tapered, conical portion of the spinal cord. Inferior to the lumbar enlargement.
Term
What do ependymal cells do?
Definition
line the cavities of the brain and spinal cord, secrete and circulate CSF.
Term
what is the brain barrier system?
Definition
a system which strictly regulates what substances can get from the bloodstream tinto the tissue fluid of the brain.
Term
what is the blood-brain barrier?
Definition
found at blood capillaries throughout the brain tissue. consists of tight junctions between the endothelial cells that from the capillary walls taht completely seal off gaps between them.
Term
what is the blood-CSF barrier?
Definition
at choroid plexuses, tight junctions between ependymal cells.
Term
how can the brain barrier system be a disadvantage?
Definition
can be an obstacle to the delivery of medicaations such as antibiotics and cancer drugs, which complicates the treatment of brain diseases.
Term
what is white matter?
Definition
groups of myelinated axons. areas in which electrical messages are going somewhere.
Term
what is gray matter?
Definition
neuronal cell bodies, dendrites, unmyelinated axons, axon terminals, and neuroglia. messages are being received, integrated, and transferred on to other cells.
Term
where is gray matter found?
Definition
surface of the cerebrum and cerebellum. also, many nuclei, found deep within the brain tissue. places where messages are going from one nerve cell to another.
Term
what is the pattern of gray and white matter in the spinal cord?
Definition
reversed from the brain: -gray matter is most internal, butterfly shape. White matter surrounds the gray.
Term
what are the 3 categories of white matter fibers?
Definition
association tracts- conduct impulses between gyri in the same hemisphere
commissural tracts- corresponding place on one hemisphere to corresponding place on the other hemisphere.
projection fibers (tracts)- superior to inferior, vice versa- to and from diencephalon, brainstem, cerebellum, and spinal cord.
Term
what is the general function of association areas of the cerebral cortex?
Definition
interpret incoming data and/or coordinate a motor response.
Term
what do the somatosensory asssociation areas monitor?
Definition
activity in the right and left primary sensory cortex. smell, sight, hearing all have their own areas.
Term
where is the primary somatosensory cortex?
Definition
in the post-central gyrus.
Term
where is the primary motor association area?
Definition
pre-central gyrus
Term
what does the somatic motor association area responsible for?
Definition
coordinating learned movements. the motor association areas can direct which neurons in the primary motor cortex will fire.
Term
what are integrative centers?
Definition
areas of the cortex which receive information from many different association areas, direct complex motor activities, and perform analytical functions. integrative centers concerned with complex processes such as speech, writing, mathematical computation, or understanding spatial relationships tend to be restricted to either the right or left hemisphere.
Term
describe the medulla
Definition
continuation of spinal cord, forms inferior part of the brain stem.
Term
what is contained in the medulla?
Definition
ALL ascending (sensory) tracts and descending (motor) tracts that connect the spinal cord with the brain.
cardiovascular center which regulates the rate and force of the heartbeat and diameter of blood vessels
breathing center which adjusts the basic rhythm of breathing.
centers for vomiting, coughing, sneezing, swallowing, and hiccupping.
Term
where are the nuclei for cranial nerves 8-12 found?
Definition
medulla
Term
where can neurons which communicate with the cerebellum to ensure precise voluntary movements, maintain equilibrium, and posture be found?
Definition
medulla
Term
describe the pons
Definition
means bridge- located superior to the medulla and anterior to the cerebellum
has white matter tracts which connect the spinal cord with the brain and parts of the brain with each other.
nuclei for cranial nerves 5-8
two additional centers that regulate breathing.
Term
describe the cerebral peduncles
Definition
primarily just conductin pathways for ascending information going to the thalamus, and descending information from the primary motor cortex.
Term
describe the corpora quadrigemina
Definition
largely gray matter, the 2 superior colliculi are reflex centers for movement of the eyes, head, and neck in response to mainly visual stimuli; the two inferior colliculi are reflex centers from movement of the head and trunk in response to auditory stimuli.
Term
describe the pineal gland
Definition
physiological role is not completely understood, is an endocrine gland which secretes melatonin; more melatonin is secreted during darkness and is thought to promote sleep and contribute to setting the bodies biological clock. also a role in reproductive function.
Term
describe the cerebellum
Definition
contains important reflex centers for muscle tone and equilibrium/balance.
voluntary muscle activity is initiated by the cerebrum, but coordinated in the cerebellum.
makes possible all skilled motor activity.
Term
describe the hypothalamus
Definition
small but very important area of the brain, mainly composed of nuclei whose neurons control many body activityies and are major regulators of homeostasis.
Term
where is the autonomic nervous system controlled?
Definition
in the hypothalamus. regulates visceral activities such as urination, movement of food through the digestive tract, heart rate
Term
what part of the brain produces several hormones and numerous releasing factors for pituitary hormones?
Definition
hypothalamus
Term
what part of the brain plays a role in regulating expression of the more intense emotional responses?
Definition
hypothalamus
Term
what part of the brain regulates patterns of eating and drinking, temperature, and plays a role in circadian rhythms and states of consciousness?
Definition
hypothalamus
Term
what part of the brain acts as a synapse and relay center for the cerebrum, like a filter and doesn't send all sensory input to the cerebrum
Definition
thalamus
Term
what part of the brain has a crude perception of painful, thermal, and pressure sensations?
Definition
thalamus. Precise localization would depend on impulses reaching the cerebral cortex, however.
Term
*what part of the brain relays motor information from the cerebellum and brain stem?
Definition
Thalamus
Term
what part of the brain plays a role in certain emotions, arousal, cognition, awareness, learning, and memory?
Definition
thalamus
Term
what is the brain stem?
Definition
the part of the brain between the spinal cord and the diencephalon. it consists of three structurally and functionally connected regions: the medulla oblongata, the pons, and the midbrain.
Term
what is the reticular formation?
Definition
a net-like region of interspersed gray and white matter extending through the brain stem.
Term
what is the diencephalon?
Definition
contains the thalamus, hypothalamus, epithalamus, and subthalamus and extends from the brain stem to the cerebrum, surrounding the third ventricle.
Term
what is the reticular activating system?
Definition
part of the reticular formation which send a continuous stream of impulses to the cerebral cortex, which keeps the cortex alert and conscious and enhances its excitability.
-all main ascending sensory tracts synaps with the RA, which keeps them active and enhances their arousing effect on the cerebrum.
Term
functions of RAS
Definition
acts like a filter for the flood of sensory input, filtering out repetitive, familiar, or weak signals.
Term
what would happen if the RAS was severely injured?
Definition
permanent unconsciousness, or an irreversible coma.
Term
functions of cerebrum
Definition
higher brain functions, like interpretation of sensory input, initiating voluntary muscular movements, memory, and integrating information for reasoning.
Term
where are the primary motor areas of the cerebral cortex?
Definition
frontal lobes, anterior to the central sulcus and in its anterior wall
Term
where is Broca's area and what does it do?
Definition
anterior to the primary motor cortex, regulates patterns of breathing and vocalization needed for normal speech.
Term
what part of the brain contains all of the following: thalamus, hypothalamus, optic chiasma, infundibulum, posterior pituitary, mammillary bodies, and pineal gland?
Definition
diencephalon
Term
what is the infundibulum?
Definition
attachment for the pituitary gland.
Term
what effects do changing activity levels in the reticular formation have?
Definition
decreased activity results in sleep, increased activity results in wakefulness.
Term
what type of information is being processed in Wernicke's area?
Definition
receives information from all sensory association areas, integrates sensory information and coordinates access to complex visual and auditory memories.
Term
what is the function of the left hemisphere?
Definition
important for reasoning, math, and science skills, spoken, written, and sign language; processes that require linear thinking.
Term
what is the function of the right hemisphere?
Definition
musical and artistic awareness, spatial and pattern perception, recognition of faces, discriminating smells, and the emotional content of language; processes that require what is called serial thinking.
Term
what is the falx cerebrei?
Definition
the double layer of meninges in the medial longitudinal fissue
Term
what is the tentorium?
Definition
double layer of meninges in the transverse fissure.
Term
what are the 3 major regions of the brainstem?
Definition
medulla oblongata, pons varolii, cerebrellum
Term
what are the 2 major regions of the midbrain?
Definition
corporal quadrigemina, cerebral peduncles
Term
what are the 3 major regions of the diencephalon?
Definition
thalamus, hypothalamus, pineal gland
Term
what brain region is the pituitary gland attached to?
Definition
hypothalamus
Term
name of the small cavity around the intermediate mass of the thalamus which contains CSF
Definition
third ventricle
Term
name of the small cavity between the cerebellum and the medulla which contains CSF
Definition
fourth ventricle
Term
name of the vacities on either side of the septum pellucidum which contains CSF
Definition
lateral ventricles
Term
what is the name of the membrane which links the fornix and the corpus callosum?
Definition
septum pellucidum
Term
what is the band of tissue below the corpus callosum?
Definition
fornix
Term
what is the involuntary brain center that plays a critical role in coordination of skeletal muscle activity?
Definition
Cerebellum
Term
brain center that is primary location of such characteristics as reason, willpower, memory, emotions, and motivation
Definition
frontal lobe
Term
brain region that includes nonvital centers for actions such as vomiting, sneezing, coughing, and swallowing
Definition
medulla oblongata
Term
primary motor area of cerebrum
Definition
frontal lobe
Term
involuntary brain center that includes control centers for sleep, hunger, satiation, and a vareity of intense emotional responses
Definition
hypothalamus
Term
brain region that includes vital centers for involuntary control of heart function, respiratory function, and vasomotor activity
Definition
medulla oblongata
Term
brain center that regulates body temperature via control of vasomotor activity, sweating and shivering
Definition
hypothalamus
Term
brain center that functions as the master gland of the endocrine system
Definition
pituitary gland
Term
primary visual area of cerebrum
Definition
occipital
Term
brain center that acts as a primary organizational control center for all information entering the cerebrum
Definition
thalamus
Term
brain center that includes involuntary centers critical to maintenance of muscle tone, equilibrium and posture
Definition
cerebellum
Term
speech is centered in this lobe of the cerebrum
Definition
frontal lobe, often left
Term
primary general sensory area of cerebrum
Definition
primary somatosensory cortex, post central gyrus, parietal lobe
Term
only part of the brain the average person has learned conscious control of
Definition
cerebrum
Term
what is the importance of the fact taht the surface of the cerebral hemispheres is highly convoluted?
Definition
the gyri and sulci increase the surface area of the cerebral cortex to allow more complex interaction between neurons.
Term
what is the importance of the corpus callosum?
Definition
it is the primary nerve pathway connecting the right and left cerebral hemispheres, allowing for communication
Term
what is the importance of the ventricles of the brain?
Definition
production and circulation of CSF, helps prevent brain from rolling- keep in an upright position
Term
what functions are taking place in the gray matter of the spinal cord?
Definition
integration of sensory and motor functions- neurons communicating via synapses
Term
what functions are taking place in the white matter of the spinal cord?
Definition
electricity/nerve impulses are going somewhere. Like a highway
Term
what functions are taking place at the spinal nerve?
Definition
contains the axons of sensory (toward CNS) and motor (away from CNS) neurons; nerve impulses.
Term
what functions are taking place in the anterior ventral root?
Definition
contains axons of soamtic motor and visceral motor neurons, carrying away from CNS
Term
what functions are taking place in the posterior dorsal root?
Definition
carrying sensory info to the spinal cord
Term
what functions are taking place at the posterior dorsal root ganglion?
Definition
contains cell bodies of unipolar sensory neurons whose axons carry info to the spinal cord.
Term
after the spinal nerve enters the intervertabral foramen, it splits into ___________ and ____________
Definition
anterior and posterior ventral roots.
Term
what are 4 characteristics of a nerve circuit that would make it qualify as a reflex?
Definition
1. requires stimulation
2. quick
3. involuntary
4. stereotyped
Term
how does a simple stretch reflex like the knee-jerk reflex differ from the typical disynaptic flexor?
Definition
only the sensory neuron and motor neuron are involved.
Term
how would a sensory neiuron initiate a nerve pathway to the brain that would result in sensory awareness?
Definition
axon collateral: sensory neuron will have an axon collateral which ascends the spinal cord to the cerebral cortex.
Term
how many neurons does it typically take for a nerve impulse to travel from a receptor to the cerebral cortex?
Definition
3: sensory from receptor to spinal cord, interneuron to thalamus, interneuron to primary somatosensory cortex (post-central gyri)
Term
contrast the term neuron with the term nerve
Definition
a neuron is a single cells and is found in both PNS and SNS; a nerve is composed of multiple neurons' axons, and is covered by 3 layers, contain blood vessels, and in PNS.
Term
where are tracts found?
Definition
white matter
Term
Are spinal nerves sensory, motor, or mixed in terms of their function?
Definition
mixed
Term
what are the 5 categories of spinal nerves, and how many of each type?
Definition
1. cervical 8 pairs
2. thoracic 12 pairs
3. lumbar 5 pairs
4. sacral 5 pairs
5. coccygeal 1 pair

31 total pairs.
Term
what is a plexus?
Definition
a branching network of intersecting and intermingling spinal nerves.
Term
what are the 5 plexuses?
Definition
1. cervical plexus- from cervical vert
2. brachial plexus- head down arm
3. lumbar plexus- from lumbar vert
4. sacral plexus- from sacral vert
5. coccygeal plexus- from coccygeal vert
Term
where does the phrenic nerve originate and where do its nerve fibers go?
Definition
cervical plexus, to diaphragm
Term
where does the sciatic nerve originate, and where do its motor fibers go?
Definition
sacral plexus, many muscles of the leg
Term
what is a dermatome, as it relates to spinal nerves?
Definition
the spcific bilateral region of the skin surface monitored by a single pair of spinal nerves.
Term
how many cranial nerves are there?
Definition
12
Term
what are the 12 cranial nerves?
(On Occasion Our Trusty Truck Acts Funny--Very Good Vehicle Any How.)
for each, state primarily sensory, motor, or mixed, and its general function
(Some Say Marry Money, But My Brothers Say Bad Business, Marry Money.)
Definition
I. olfactory- sensory-smell
II. optic-sensory-vision
III. oculomotor-motor-eye & eyelid muscles
IV. trochlear-motor-eye & eyelid muscles
V. trigeminal-mixed- sensory to mouth and front of face, motor- muscles for chewing
VI. abducens-motor-eye movements
VII. facial-mixed-sensory mostly taste motor- tear and saliva secretion, facial expression
VIII.vestibulocochlear- sensory-hearing, balance
IX. glossopharyngeal-mixed-sensory taste, motor saliva secretion
X. vagus-mixed-sensory info from all organs in viscera motor-for all organs in viscera
XI. accessory-motor-swallowing, movement of food
XII. hypoglossal- mostly motor, tongue
Term
what overall effect does the Parasympathetic Nervous system have on the body?
Definition
SLUDD-salivation, lacrimation, urination, digestion, defecation. Feed & Breed or rest & digest.
Term
what overall effect does the sympathetic nervous system have on the body?
Definition
prepares the body for heightened levels of somatic activity- fight or flight.
Term
what is dual innervation?
Definition
receiveing nerve fibers from both SNS and PSNS.
Term
where do sympathetic nervous system pathways leave the CNS?
Definition
thoracolumbar- from LATERAL GRAY HORN of spinal cord in T1-T12, L1&L2 region
Term
where do parasympathetic nerve pathways leave the CNS?
Definition
the nuclei of 4 pairs of cranial nerves found in brainstem- Occulomotor(III), facial (VII), glossopharyngeal(IX), and vagus(X)
Term
where are any synapses found in PSNS?
Definition
GANGLIA! close to effectors.
Term
where are any synapses found in SNS?
Definition
GANGLIA!! prevertebral and paravertebral
Term
what is the sympathetic trunk?
Definition
chains of sympathetic ganglia which run adjacent to the spinal cord.
Term
what is the central control of autonomic function?
Definition
hypothalamus- can be influenced by many other parts of the brain, but the hypo decides whether PNS or SNS response required.
Term
compare autonomic motor pathways and somatic motor pathways
Definition
Somatic- go to skeletal via one neuron between CNS and effector cell
Autonomic- go to smooth and cardiac muscles and glands via 2 neurons and one ganglion.
Term
what is the solar plexus?
Definition
the major sympathetic precertebral ganglia.
Term
an example of cooperative sympathetic and parasympathetic
Definition
Iris of eye; 2 layers of smooth muscle: circular smooth muscle controlled by parasympathetic contract to make pupil smaller--radial smooth muscled controlled by sympathetic dilates pupil when contracted.
Term
places in the body which only have sympathetic nervous stimulation
Definition
adrenal medulla-epinephrine
piloerector muscle and sweat glands
kidney
most blood vessels
--SNS is always sending certain level of signals to smooth muscle in blood vessels. To constrict, increase signal rate. to dilate, decrease signal rate.
Term
what are cholinergic neurons?
Definition
those which release acetylcholine
ALL pre-ganglionic
ALL parasympathetic postgangionic
A few sympathetic postganglionic neurons (to sweat glands, hair follicle muscles, adipose tissue, and some blood vessels.)
Term
what are adrenergic neurons?
Definition
those which release norepinephrine
-MOST sympathetic postganglionic neurons.
Term
the next cell down the line from a cholinergic neuron will have _________ receptors in its cell membrane.
Definition
cholinergic
Term
what are the 2 types of cholinergic receptors
Definition
Nicotinic (alpha)- ALL postganglions- ALWAYS excitatory.
Muscarinic (beta- could be excitatory or inhibitory
Term
what does an alpha receptor do?
Definition
ALMOST always leade to excitation of the effector.
Term
what does a beta receptor do?
Definition
either excitation or inhibition of the effector.
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