Exam 1 andserson Flashcards
(108 cards)
1
Q
CNS
A
brain & spinal cord; structures arise directly from neural tube
2
Q
4 Cn carry parasym fibers
A
3,8,9,10
3
Q
PNS definition
A
made up of transmission pathways carrying info btwn CNS and ext./Int. environments
4
Q
PNS contents
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cranial nerves(12), spinal nerves (31), sensory receptors in skin and gut tube wall, in tendons, in skeletal muscles, and motor end plates btwn neurons and skeletal muscle fibers
5
Q
ANS
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-subdivision of PNS, entirely motor, innervates smooth muscle and glands. divided into symp and parasymp
6
Q
Nucleus
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aggregation of dendrites and nerve cell bodies in CNS
7
Q
Ganglion
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aggregation of dendrites and nerve cell bodies in the PNS
8
Q
Nerve
A
bundle of fibers (axons) in PNS
9
Q
Tract
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bundle of fibers (axons) in CNS
10
Q
Commissure
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Tract in the CNS that crosses from one side to other
11
Q
White matter
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areas of myelinated axons
12
Q
gray matter
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areas of unmyelinated axons, cell bodies & dendrites
13
Q
When does neural tube form?
A
during embryonic stage, end of 2nd week to 8th week ;
1. neural plate, then folds then tube
14
Q
Tripartite brain
A
Prosencephalon—> T and D
Mesencephalon–> Mesen
Rhomboencephalon–> Meten and myelen
15
Q
Anencephaly
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failure of the cranial end of the neural tube to close
16
Q
Holoprosencephaly
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failure of the prosencephalon to divide into 2 cerebral hemispheres- often results in facial deformities
17
Q
Spina Bifida-occulta
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Failure of the inferior neuropore to close, vetebral arches fail to develop in caudal area, spinal cord function is usually normal
18
Q
Spina Bifida-Cystica
A
sac-like cyst at caudal spine, spinal cord a/o meninges maybe in cyst, spinal cord function impaired, maybe lower extremity dysfunction, bladder and bowel funtion maybe impaired
19
Q
Meningocele
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a form of spina bifida cystica, only meninges found in sac, spinal cord function impaired, location and severity of malformation dictate signs and symptoms
20
Q
Meningomyelocele
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a form of spina bifida cystica, meninges and spnal cord in sac, always results in abnormal spinal cord growth, lower extremity paralysis, bowel and bladder disfunc., loss of lower limb sensation
21
Q
Myeloschisis
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a form of spina bifida cystica, failure of caudal neural folds to close, most severe of the defects
22
Q
Arnold-Chiari Deformity
A
inferior cerebellum and medulla are elongated and protrude into vertebral canal, medula and pons are small and deformed, hydrocephalus, malformation of lower cranial nerves-deafness, tongue, facial muscle, lateral eye movement weakness
23
Q
Epithalamus
A
Habenular neclei involved in emotional and visceral responses to odors,
24
Q
Thalamus
A
relay station for afferent and efferent info to/from cerebrum and other areas of brain, 80% of diencephalon, landmaks are optic recess, infundibular recess, pineal recess
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Hypothalamus
Mamillary bodies involved in olfactory reflexes and emotional responses to odors; supraoptic and paraventricular nuclei
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Diencephalon
epithalmus, thalamus and hypothalamus. Controls and integrates ANS, associated with visceral activity, intermediary btwn nervous and endocrine systems, controls normal body temp, maintains extracellular fluid volume
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Cerebellum definition
has cortex, connected to other parts of brain via large fiber tracts called peduncles.
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Cerebellum functions
coordinate skeletal muscle movements, maintain equilibrium and posture, synergic control of muscle activity
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Axon
part of neuron that carries info to another neuron or muscle cell, conducts action potential, membrane is axolemma, cytoplasm is axoplasm.; only part of neuron that is ever myelinated (myelin formed by schwann cells)
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Spinal nerve branches
2 division: dorsal primary ramus & ventral primary ramus; thoracolumbar have 2 small branches prior to primary What ramus and gray ramus communicans
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White ramus communicans
carries myelinated preganglionic fibers
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gray ramus communicans
carries unmyelinated postganglionic fibers back to spinal nerve
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Paravertebral ganglia
linked together into a long chain on either side of vertebral column in thoracolumbar region, site of cell bodies of postganglionic sympathetic nerves, site of synapse btwn preganglionic myelinated symp neurons & postgangnon-myelinated sypm neurons
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Splanchnic nerve
a nerve supplying viscera
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Prevertebral ganglion
typically found anterior to abdominal aorta, site of synapses btwn preganglionic myelinated sympathetic neurons & postganglionic non-myelinated neurons
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Physiological states of neuron
Resting: cell body potential aprox -65 mv
Excited: cell body more ++; approx -45 mv (this is due to influx of sodium ions)
Inhibited: cell body potential is more negative than at rest, -70 mv, (influx of chloride ion or efflux of potassium ion
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Acetylcholine secreted by: (major neurotransmitter)
pyramidal cells, some neurons in bsal ganglia, alpha motor neurons, preganglionic neurons in ANS, postganglionic neurons of parasymp system, some postganglionic neurons of the symp system. (usually excitatory)
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Acetylcholine targeted by: (major neurotransmitter)
nicotine, chantix, sarin, aricept (alzheimer's), botox, tensolin, biperiden
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Norepinephrine secreted by: (major neurotransmitter)
many neurons located in brain stem and hypothalamus, some neurons located in pons, most postganglionic neurons of symp system (can be excitatory or inhibitory)
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Dopamine secreted by: (major neurotransmitter)
most neurons originating in substantia nigra, usually inhibitory
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Norepinephrine targeted by: (major neurotransmitter)
amphetamines, cocaine, cymbalta, propranolol
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Dopamine targeted by: (major neurotransmitter)
Amphetamines, cocaine, levadopa (parkinsons), haldol (alzheimer's)
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Glycine (major neurotransmitter)
secreted by synapses in spinal cord. Always inhibitory; not a drug target
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GABA (major neurotransmitter)
Secreted by many areas in the spinal cord and cerebral cortex, always inhibitory, targeted by alcohol, barbiturates, valium, baclofen
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Glutamate (major neurotransmitter)
secreted by many sensory pathways entering the CNS, many areas of cerebral cortex, always excitatory, targeted by ketamine (anesthetic) namenda (alzheimer's), robitussin
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Dendrite characteristics
may extend out large distance, can recieve siganls from large spatial area; generally cannot transmit APs, they use electronic conduction instead, long with thin membranes
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Dendritic membranes
Ar thin, partially permeable to K and Cl, much of the potential lost due to leakage, gradual loss of potential as the depolarization spreads from site of initiation results in DECREMENTAL conduction
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electronic conduction
direct spread of electrical current by ion conduction in the dendritic fluids wo generating action potential
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Synaptic delay-Dendrite characteristics
refers to the time it takes to transmit a signal from a presynaptic neuron to postsynaptic neuron; depends on: time it takes to release neurotransmitter, time it takes for neurotransmitter to diffuse across cleft, how nt acts on postsynaptic membrane, time it takes for the receptor to inc. membrane permeability, time it takes for the inward diffusion of Na ions
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2 sources of blood supply to brain
Vertebral arteries & internal carotids
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Vertebral arteries
1 of 2 sources of blood to brain, 1st branches of subclavian, ascend thru transverse foramina of CV 1-6, pass foramen magnum, unite at caudal border of pons to form basilar artery
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Internal carotids
1 of 2 blood to brain, terminal branches of the common carotids, enter cranial cavity through carotid canal in temporal bone
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Circle of Willis
pentagonal shaped circle of arteries on ventral surface of the brain that unites the 2 vertebral and 2 internal carotid arteries
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Components of Circle of Willis
Posterior cerebral arteries (terminal branches of basilar); Posterior communicating arteries (connect post, cerebral to internal carotids) Internal carotids (give off anterior & middle cerebral aa), anterior cerebral aa (branches of ICA), anterior communicating (unpaired) connext 2 anterior
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Telencephalon components
cerebral hemispheres, olfactory bulb, basal nuclei (ganglia)
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Cerebral Hemispheres
80% of brain mass, gyri and sulci, left and right hemispheres (falx cerebri), superior to cerebellum (tentorium cerebelli)
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5 cerebral lobes
Occipital, parietal, frontal, temporal, insula
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Occipital lobe
vision, correlates visual images w visual memory, involved in conscious perception of vision, seperated from parietal lobe by parietooccipital sulcus
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Parietal Lobe
Somatesthetic interpretation (post central gyrus), understanding speech (auditory association cortex, wenickes area), formulating words, central sulcus is landmark separates motor cortex from sensory cortex
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Frontal Lobe
voluntary motor control (precentral gyrus), motivation, aggression, mood, personality, cognitive processes, brocas
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Temporal lobe
Receives/interprets olfactory and auditory sensation, storage of memory related to auditory and visual experiences
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insula
not observed from surface, involved w memory, psychic cortex: highest levels of brain function, absract thought, judgement
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Corpus Striatum
part of the basal ganglia of the brain, comprising the caudate and lentiform nuclei.
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caudate nucleus
large subconscious movements of skeletal muscle
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lentiform nucleus
1. putamen- large subconscious movements of skeletal muscle
| 2. globus pallidus-regulates muscle tone
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Types of cortical neurons
1. granular (stellate)-short axons, interneurons, both ecitatory (glutamate) and inhibitory(GABA)
2. Fusiform-smaller output neurons
3. pyramidal- large output neurons
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Primary motor areas: primary cortical area
direct connections w specific muscles
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Primary sensory areas: primary cortical area
detect specific sensations
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secondary motor areas primary cortical area
provides patterns of motor activity
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secondary sensory areas primary cortical area
analyze meanings of specific sensory signals
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Association areas definition
receive & analyze signals simultaneously from multiple motor and sensory cortices
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Parieto-occipitotemporal association area
prefrontal association area, limbic assoc. area, brocas and wernickes
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prefrontal assoc. area
receives pre analyzed sensory info (esp concerning spatial coordinates) necessary for planning movements, output passes through caudate portion of basal ganglia, carries 'thought' processes in the mind
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limbic association area
concerned w behavior, emotions, motivations
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brocas area
provides circuitry for word formation, works closely with wernickes, almost always dominant on eft side of brain
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Corpus callosum
major commissure btwn the 2 hemispheres, cutting results in: blocking info from wernickes area to nondominant motor cortex, prevention of the transfer of somatic and visual info from right hemisphere to wernikes, results in 2 entirely separate conscious portions of brain
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declarative memory
refers to memory of various details of an integrated thought. might include memory of: surrounding, time relationships, causes of experience, meaning of experience, deductions as result of experience
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Reflexive (skill) memory
associated w motor activities
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Short term memory
Exemplified by memory of a telephone number, lasts only as long as person thinks of number or facts (seconds)
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Intermediate long term memory
last minutes or weeks, may become long term memory if memory traces are activated enough
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long term memory
structural changes include inc in vesicle release sites for secretion of transmitter substance, inc in presynaptic terminals
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5 basic types of sensory receptors
1.mechanoreceptors 2. thermoreceptors 3. nociceptors 4. electromagnetic receptors 5. chemoreceptors
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mechanoreceptors
skin tactile sensibilities and deep tissue sensibilites. can be both free and encapsulated
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Expanded tip ending mechanoreceptors-skin tactile
merkels disc, other varients
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encapsulated ending mechanoreceptors-skin tactile
meissners corpuscles, kraus corpuscles
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mechanoreceptor deep tissue spray ending
ruffinis corpuscle
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mechanoreceptor deep tissue encapsulated
pacinian corpuscle and other varients
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mechanoreceptors not skin/deep tissue
hearing-sound receptors in cochlea
eqilibrium- vestibular receptors
arterial pressure- baroreceptors
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Nociceptors
free nerve endings responding to pain
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electromagnetic receptors
include rods and cones of the eye for vision
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chemoreceptors
taste, smell, arterial oxygen, osmolarity, blood CO2, blood glucose, amino acids, fatty acids
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thermoreceptors
cold and warm receptors
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differential sensitivity
a receptor characteristic-each type of receptor is highly sensitive to one type of stimulus and is almost unresponsive to other types
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modality
a receptor characteristic-refers to each of the principle types of sensation
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labeled line principle
a receptor characteristic-refers to the specificity of nerve fibers for transmitting only one modality of sensation
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adaptation
a receptor characteristic-all sensory receptors adapt either partially or completely to any constant stimulus after a period of time, some receptors adapt to a far greater extent than others
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Tonic receptors definition
Slow adapting, detect continuous stimulus strength, trasmit impulses as long as stimulus is present,
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types of tonic receptors
muscle spindles, golgi tendon organs, macula and vestibular receptors, baroreceptors, chemoreceptors
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phasic receptors
rapidly adapting, do not transmit continuous signal, stimulated only when stimulus strength changes, transmit information regarding rate of change
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Type A nerve type fiber
further subdivided into alpha, beta, gamma and delta. Large and medium sized myelinated fibers of spinal nerves
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Type C nerve fibers
small, unmyelinated fibers, conduct signals at low velocity, make up more than half of all sensory fibers in most peripheral nerves and all postganglionic autonomic fibers
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Group 1a nerve fibers
type A-alpha-fibers from annulospiral endings of muscle spindles
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Group 1b nerve fibers
type A-alpha-fibers from golgi tendon organ
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Group 2 nerve fibers
Type A-beta/gamma fibers from cutaneus tactile receptors and flower spray
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Group 3 nerve fibers
Type A delta fibers carry temp., crude touch, and pricking pain
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Group 4 nerve fibers
Type C fibers carry pain, itch, temp and crude touch
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spatial summation
increasing signal strength is transmitted by using progressively greater number of fibers. nerve endings from 1 fiber overlap those of the other pain fiber
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temporal summation
increase signal strength by increasing frequency of nerve impulses in each fiber
