Z332 midterm 1 Flashcards
Neo-cortex
most of cerebral cortex in mammals
6 layers
Neuronal migration
cns neurons originate from progenitor cells in ventricular zone, remain in neural tube structures, cerebral cortex neurons travel several mm
neural tube defects associated with
folic acid deficiency
spina bifida
failure of neural tube to close at posterior end, mental retardation
anencephaly
failure of neural tube to close at rostral end, most die
PNS develops from
neural crest cells
contains trigger zone where action potentials are initiated
axon initial segment (AIS)
synapse
junction between two neurons or neuron and effector cell; transmits nerve impulse
afferent neurons
sensory, carry nerve impulses toward CNS
efferent neurons
motor, cause effect, carry impulse away from CNS
interneuron
between neurons, integrate information
multipolar neurons
most common, found in CNS and autonomic ganglia, interneurons, motor neurons
bipolar neurons
one axon one dendrite, rare, special senses
unipolar neurons
sensory, PNS, trigger zone at junction of dendrites and axon
sciatic nerve
longest and thickest nerve, spinal cord to bottom of foot, over 1 meter long, formed by 5 spinal nerves (L4-S3)
anterograde transport
cell body to axon synapse, slow and fast, pre-peptide precursors
retrograde transport
recycling proteins and neurotransmitters, mitochondria, fast only
ALS
amyotrophic lateral sclerosis/ Lou Gehrig’s disease, progressive lethal degenerative disorder of motor neurons, paralysis of voluntary muscles
concus medullaris
end of spinal cord ~L1-L2
epidural space between
dura mater and bone
CSF in space between
arachnoid mater and pia mater
lumbar puncture in
subarachnoid space
lumbar puncture measures
CSF pressure
high CSF pressure
cerebral edema, subarachoid hemorrhage, meningeal inflammation, meningitis
low CSF pressure
subarachnoid blockage, leaks, dehydration
spinal cord smaller caudally because
less sensory and motor tracts
more white matter cranially because
more sensory tracts cranially, more motor tracts caudally
posterior/dorsal horn
afferent neurons, ascending
anterior/ventral horn
efferent neurons, descending
epineurium continuous with
dura mater
spinal nerves emerge through
intervertebral foramina
mixed nerves
all spinal nerves, sensory and motor info
cervical plexus
C1-C5; neck, thoracic cavity, diaphragm; phrenic nerve
brachial plexus
C5-T1; pectoral girdle and upper limb
nerves: musculocutaneous, axillary, median, ulnar, radial
lumbar plexus
T12-L4; pelvic girdle and lower limb
nerves: femoral, obtruator
sacral plexus
L4-S4, pelvic girdle and lower limb
nerves: sciatic, tibial, common fibular
components of relex
receptor, sensory neuron, integration center, motor neuron, effector
cranial nerves
olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, vestibulocochlear, glossopharyngeal, vagus, accessory, hypoglossal
Cranial nerve II
optic, vision/visual pathway
cranial nerve III
oculomotor, eye movement, 4 of 6 extrinsic eye muscles; control pupil diameter of iris
pupil constriction
circular muscles, parasympathetic innervation
pupil dilation
radial muscles, sympathetic innervation
Rest, Relax, aRousal, digest
parasympathetic
fight, fright, flight, fuck
sympathetic
reflex
stereotyped, involuntary unconscious response to stimuli
receptor, sensory neuron, integrating center, motor neuron, effector
pupillary reflex
sensory nerve = optic (II)
motor nerve = oculomotor (III)
4 of 6 extrinsic eye muscles for oculomotor
superior rectus, inferior rectus, medial rectus, inferior oblique
cranial nerve IV
trochlear, eye movement superior oblique
cranial nerve V
trigeminal, 3 branches: ophthalmic, maxillary, mandibular
ophthalmic branch of V
sensory of upper face (and cornea)
corneal reflex
sensory nerve = ophthalmic branch of trigeminal
motor = facial (VII)
maxillary branch of V
sensory to face (over mandible)
mandibular branch of V
sensory over mandible, tongue (tactile), muscles of mastication
cranial nerve VI
abducens, eye movement - lateral rectus
cranial nerve VII
facial; sensory: face and taste; motor: secretion of tears and saliva (parasympathetic), facial, scalp, and neck muscles
cranial nerve VIII
vestibulocochlear, hearing and balance
cranial nerve IX
glossopharyngeal; sensory: taste (posterior 1/3), blood pressure, CO2; motor: swallowing and speech
cranial nerve X
vagus; 75-80% of parasympathetic ANS; sensory: blood pressure, breathing rate and depth, touch in throat; motor: swallowing, coughing, voice production
gag reflex
sensory = glossophyrangeal motor = vagus
cranial nerve XI
accessory; mediated head movement and pectoral girdle
cranial nerve XII
hypoglossal; swallowing, tongue movement during speech,
acoustic startle response
sensory= bestibulocochlear motor = accessory (trapezius and sternocledomastoid)
somatic motor division does not have
ganglia
heavily myelated axons in ______ nervous system
somatic
sympathetic neurons release
norepinephrine ( and acetylcholine)
parasympathetic neurons release
acetylcholine
in autonomic, sensory inputs from
interoceptors (sensory receptors in viscera)
outputs of autonomic nervous system
limbic system, hypothalamus, spinal cord, brain stem, ganglia
effectors of autonomic nervous system
smooth muscle, cardiac muscle, glands, adipose tissue
ANS pathways have
2 neurons, preganglionic neuron and postganglionic neuron
craniosacral
parasympathetic nerves
thoracolumbar
sympathetic neurons
long preganglionic fibers, short postganglionic
parasympathetic
short preglandlionic fibers, long postganglionic
sympathetic
ganglia in parasympathetic
in visceral effectors
ganglia in sympathetic
near spinal cord
postganglionic synapse of sympathetic release
ACh and NE
postganglionic synapse of parasympathetic release
ACh
all preganglionic sympathetic and parasympathetic cells release
ACh
cholinergic
fibers that release ACh
adrenergic
fibers that release NE
location of preganglionic neurons in parasympathetic
nuclei of cranial nerves, lateral gray horn sacral segments
1 kind of ganglia in parasympathetic
terminal ganglia, post ganglionic fibers go to single effector
parasympathetic has specific and localized…
actions
location of preganglionic neurons in sympathetic
lateral horns of spinal cord, thoracic to lumbar
2 types of ganglia in sympathetic
sympathetic trunk ganglia (above diaphragm), prevertebral (collateral) ganglia (below diaphragm)
…both close to spinal cord
from T5 down most preganglionic fibers synapse…
in collateral ganglia
can affect entire body simultaneously
sympathetic responses
parasympathetic acts to…
conserve and store energy
SLUDD (salivation, lacrimation, urination, digestion, defecation)
sympathetic acts to…
prepare fora and maintain physical activity (exercise , excitement, embarrassment)
neurotransmitter action depends on
receptor it binds to
short vs. long lived effects
sympathetic = longer lived parasympathetic = short lived
areas affected by sympathetic/parasympathetic
parasympathetic = local sympathetic = whole body
synapse density sympathetic/parasympathetic
para = small, 1 pre 6 post sympathetic = large, 1 pre 32 post
autonomic tone
balance between sympathetic and parasympathetic, regulated by hypothalamus
in awakened state body maintains ____ tone
sympathetic ex: book vessel diameter
rest
more parasympathetic
stress response
more sympathetic
layer protecting brain
skin, periosteum, bone, dura mater, arachnoid mater, pia mater
dural sinuses
drain venous blood into internal jugular veins
no epidural space in skull
dura mater tight to skull (2 layer fused otherwise)
arachnoid villi
protrude through inner most layer of dura mater at dural sinuses, allows CSF to move form subarachoid space into dural sinuses
layer that is sheath for blood vessesl
pia mater
blood supply to brain
carotid arteries and vertebral arteries, through capillaries and to choroid plexuses to CSF
circle of willis
connects all major arteries to brain, redundancy
blood away from brain
dural sinuses drain into internal jugular veins
substances in blood must pass through…
endothelium of capillary, basal lamina, astrocyte feet
choroid plexuses (in all 4 ventricles)
produces CSF, blood-CSF barrier
where is CSF
ventricles, central canal of spinal cord, subarachnoid space
CSF flow
lateral ventricles, 3rd ventricle, 4th ventricle, central canal OR 4th ventricle, subarachnoid space, dural sinuses, jugular vein
hydrocephaly
blockage of CSF flow, big head, congenital birth defect
inner fish
brain stem
medulla oblongata
phylogentically old, vomiting, coughing, sneezing, hiccuping, swallowing, heart rate, respiratory
nucleus gracilis
medulla oblongata, relay nuclei and sensory/ascending somatic pathway, lower trunk and limbs
nucleus cuneatus
medulla oblongata, realy nuclei in sensory somatic pathway, upper trunk and limbs
pons
bridge, sensory and motor tracts, equilibrium, breathing rate
important structures in mesencephalon (midbrain)
superior and inferior collicului, substantia nigra, red nucleus
superior collicului
visual reflexes
inferior collicului
auditory reflexes
substantia nigra and red nucleus
control movement, substantia nigra is black from melanin (dopamine precursor)
Parkinson’s disease
degeneration of substantia nigra neurons = less dopamine
cerebellum
smooths and regulates skeletal muscles, posture and balance
major structures of diencephalon
epithalamus (pineal gland), thalamus, hypothalamus
pineal gland
releases melatonin in response to photic cues
thalamus
relays sensory info to cortex, maintains consciousness, relays motor info from cerebellum to basal nuclei; connection between inner fish brain and neocortex
thalamic nuclei
limbic system involved with emotion and memory, relays sensory info, integrates sensory info, visual and auditory info
lateral geniculate nucleus
receives visual info, thalamic nuclei
medial geniculate nucleus
relays auditory info, thalamic nuclei
hypothalamus
activity of ANS, eating and thirst, temp, circadian rhythms, hormones, oxytocin
association fibes
connect different parts of same hemisphere
commissural fibers
connect corresponding gray areas of two hemispheres
projection fibers
connect cerebral cortex with lower brain centers (ascending and descending )
basal nuclei
areas of gray matter deep within cerebrum
central sulcus
separates motor and sensory areas, motor comes before sensory
primary sensory cortex
touch, pressure, pain, vibration, temp
somatosensory association area of brain
relationship of body parts, memory of somatosensory experiences,
multimodal association area
meaning to info, store in memory, link with previous experiences, decide what actions to take
prefrontal cortex
most complex, personality, intellect, reasoning, judgment, concern, abstract though, linked to limbic system, inhibiting impulsive behavior
wernicke’s area
left parietal lobe, understanding language, damage causes aphasia, word salad, general interpretive area
primary motor cortex
controls voluntary contractions of specific muscle groups, response on opposite side of body, more area to muscles involved with skilled complex movement
premotor area
somatic motor association area, receives input from motor cortex and sensory association areas, complex and sequential learned motor activities
broca’s area
control speech, damage leads to non fluent aphasia, understand but difficulty speaking, in left hemisphere
imparts emotion to speech
right side of brain
left brain
dominant 90% of time, reading, writing, math, decision making, speech and language, analysis
right brain
senses, recognition
limbic system
establishes emotional states, links conscious intellectual functions to unconscious autonomic functions, memory storage and retrieval;
complex and basal, evolutionary and anatomically more proximal to inner fish
limbic system functional grouping
hypothalamus at center, between cerebrum and diencephalon?
limbic lobe/cortex
critical to insight, motivation, mood, judgement, communicated directly with prefrontal lobe
hippocampus
short term memory to long term
mammilary bodies
recognition memories, smell to memories
amygdala
fear and aggression, memory of emotional events, afraid and angry behaviors
Cranial nerve nuclei in medulla oblongata
VIII, IX, X, XI, XII
Cranial nerve nuclei in pons
V VI VII VIII
Cranial nerve nuclei in mesencephalon
III IV
