Anatomy IV Exam Flashcards
Which cranial nerve is part of CNS?
CN II
What are the components of the somatic nervous system?
Sensory (Afferent), Motor (Efferent)
VOLUNTARY + reflexes
Parietal lobe
receives sensory, initiates motor
Temporal lobe
hearing, speech, memory
Broca’s area
motor function of speech, temporal/frontal
Wernicke’s area
comprehend/interpret words, temporal
How many pairs of spinal nerves?
31 pairs: 8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
Where does the first cervical nerve exit?
above first vertebra
spinal ganglia
convergence of spinal nerve roots
Layers of CNS (out to in)
Dura mater
Arachnoid mater
Pia mater
What structure causes impingement of spinal nerves?
intervertebral discs (anteriorly to exiting nerves)
What composes the intervertebral disc and what’s its function?
annulus fibrosus exteriorly
nucleus pulposus in the center
connects vertebrae above and below
Herniated disc
nucleus pulposus push out of annulus fibrosus into nerve –> impingement
Sensory/Afferent nerves emerge from which nerve root?***
Dorsal nerve root
Motor/Efferent nerves emerge from which nerve root?***
Ventral nerve root
What happens to dorsal and ventral nerve roots coming out of spine?
sensory and motor nerve roots combine as one
Cerebral cortex function
higher-level thought process, large memory storage (coordinate w/other structures)
Subcortical area function
autonomic activities, emotional patterns
Involuntary reflex function
by spinal cord
afferent signals dont need to go to brain first –> immediately back out
What does the autonomic nervous system involve?
Parasympathetic
Sympathetic
Enteric
both PNS, CNS
sensory and motor neurons divided into?
visceral and somatic
What is contained in the dorsal horn?
interneurons receiving from somatic/visceral sensory neurons
What is contained in the ventral horn?
motor neurons
What are neurons highly sensitive to?
oxygen and glucose deprivation
What do motor neurons affect?
skeletal muscles
smooth muscles
endocrine/exocrine glands
Soma function
balance positive and negative impulses –> propagate single signal
Schwann cells
surround axons in PNS, produce myelin sheath (insulate signal conductor –> faster)
Multiple Sclerosis
loss of myelin from Schwann cell damage
function of enzymes at synapses
degrade NT
Interneuron function and function in reflex arc
integrative function: direct impulses
reflex: initial processing to produce immediate response bypassing brain
Grey matter***
neuronal cell bodies* capillaries* glial cells dendrites "processing centers"
Different kinds of tracts of white matter
= axons
- projection tracts: extend vertically between higher and lower brain structures
- commissural tracts: connect L/R cerebrum
- association tracts: connect diff regions in SAME hemisphere; link perceptual and memory centers
differences in white v grey matter in spinal cord and brain
brain: grey over white
spinal: white over gret
4 main classes of neurotransmitters and examples of each
amines: ACh
monoamines: catecholamines(EPI), serotonin
amino acids: GABA, glutamate
neuropeptides: beta endorphin, ACTH, oxytocin
Acetylcholine functions
primarily excitatory (skeletal)
but INHIBITORY in cardiac muscles
help regulate attention, arousal, memory
What is the primary NT in motor division of somatic nervous system
ACh
What NT receptor does nicotine stimulate?
ACh
What disease are associated w/ACh dysfunction?
Alzheimer's (low ACh) Myasthenia gravis (ACh receptor destruction)
NE
excitatory
regulate pulse, BP, mood
physical and mental arousal
EPI
excitatory
stress
elevated –> ADHD like
DA
usually inhibitory
signaling in voluntary mvmts
associated w/REWARD mechanism
Parkinson’s Disease pathology
decreased DA
What NT do drugs like cocaine, heroine, nicotine, opium and alcohol stimulate?
DA –> reward mechanism
Schizophrenia pathology
increased DA
Serotonin
inhibitory
inhibit pain pathways
significant in emotion, mood, anxiety
Decreased serotonin effects
depression, anger, suicidal, OCD
action of SSRIs
increase Serotonin
GABA
inhibitory
low level of GABA associated with what health problem?
anxiety-related disorders
Glutamate
excitatory
learning and memory
most common NT in CNS esp brain?
Glutamate
What happens w/excess of glutamate?
neuron toxicity (ALS)
What is an associated NT pathology of ALS?
excessive glutamate
endorphins
inhibitory
resembles opioid: reduce pain and stress, induce calmness, pleasure, serenity
“endogenous morphine”
endorphins
What NT allows animals to hibernate?
Endorphins
precentral gyrus
primary motor cortex (voluntary skeletal mvmt)
signal for R side mvmt originate L (vice versa)
central sulcus
between frontal and parietal lobe
also separates primary motor and primary somatosensory cortex
Voluntary motor pathway/Corticospinal tract
travel down axon from grey area of cortex –> cross over at lower MEDULLA –>
What spinal tract crosses over at lower medulla?
corticospinal
posterior column
the two are opposite directions
What spinal tract crosses over at the spinal cord?
spinothalamic
What information does the spinothalamic tract conduct?
pain and temperature
crude touch
What are the two sensory pathways?
spinothalamic tract
posterior column
What information does the posterior column conduct?
position and vibration
fine touch
What are the two motor pathways?
corticobulbar tract
corticospinal tract
Spinothalamic (sensory) tract pathway
crosses over at level of spinal cord where it enters and travels up to cortex
What happens in hemitransection of spinal cord?
affect pain/temp on contralateral side of lesion
affect position and vibration on ipsilateral side
Reflex arc pathway
muscle –> afferent sensory fiber –> posterior root ganglion –> posterior root –> posterior horn –> interneuron –> anterior horn –> root –> fiber –> muscle
craniosynostosis
suture line shut early, stop bone growth
pterion
where 4 suture lines come together, by temporal
prone to injury
What vessel is right under pterion?
middle meningeal artery - anterior branch
What is in the brainstem?
midbrain
pons
medulla
Telencephalon
cortex
basal ganglia
amygdala
hippocampus
Diencephalon
thalamus
hypothalamus
Mesencephalon
Midbrain
Metencephalon
pons
cerebellum
Myelencephalon
medulla
corpus callosum
tract between hemispheres
gyrus
peaks of brain convolutions
longitudinal fissue
divides L/R hemisphere
sulcus
troughs of brain (central, lateral)
pre/post central gyri
pre: motor
post: somatosensory
What is frontal lobe divided into?
prefrontal
pre-motor: modifies
motor: voluntary
What side of premotor cortex controls R movement?
L
proprioception (limb position) is in which lobe?
parietal
What’s stereognosis and what lobe is it in?
identify 3D object in hand
parietal
parietal lobe functions
sensory: touch, pain, proprioception
process/integrate environment info
L Temporal damage
remember what people said
R Temporal damage
recall music/pics
Which side of brain is Wernicke’s and Broca’s in 95% of people
L
Global aphasia
complete absence of language/communication
What is unaffected in Wernicke’s?
visual/auditory
ataxia
loss of muscle coordination, cerebellum
midbrain
regulates mvmt of eyes and head
origin or CN III, IV
corpora quadrigemina
Pons
relays between cerebrum + cerebellum
pneumotaxic center
Medulla
relays between brain + spinal cord
autonomic: BP, HR, Resp, vomit
Thalamus
relays sensory and movement info between cerebrum and spine
Limbic system structures
amygdala
hippocampus
mamillary bodies
cingulate gyrus
Limbic function
emotional response to situation
hippocampus
memory, learning
Layers of dura mater
periosteal
meningeal
Where is falx cerebelli and tentorium cerebelli
falx: sagittal
tentorium: horizontal
What is in subarachnoid space?
CSF, vasculature
Which layers of meninges does meningitis usually affect?
arachnoid, pia
Where is CSF formed and what’s the pathway?
choroid plexus: lateral–>3rd–>4th–>subarachnoid
Where is CSF reabsorbed to?
sagittal sinus (to blood) by arachnoid villi
Where is needle inserted in spinal tap?
between 3rd, 4th OR 4th, 5th
What part of brain does basilar artery supply?
posterior
What artery supplies anterior/middle portion of brain?
internal carotids
What types of neurons are in Autonomic Nervous system?
preganglionic: soma in CNS
postganglionic: outside
Where are sympathetic ANS preganglionic cell bodies located?
lower thoracic and lumbar on cord
parasymp: brain stem
Integration center of ANS
Hypothalamus (parasymp: ant)
limbic system
connect to hypothalamus
danger/stress signal
Reticular formation
sleep and consciousness
Where are parasympathetic ANS preganglionic cell bodies located?
brain stem (CN 3, 7 ,9 , 10) or sacral on cord
Vagus nerve is a part of which fibers?
parasympathetic fibers
Length of axons in parasympathetic and sympathetic
symp: postganglionic longer
para: pre longer
What are the Cholinergic receptors and where are they?
nicotinic: postgang of symp and parasymp.
muscarinic: parasymp.
What are the Adrenergic receptors and where are they?
alpha 1/2, beta 1/2
both in symp.
What neurons are between the spinal cord and target organ in PNS and SNS?
Preganglionic
Postganglionic (innervate target organ)
PREganglionic fibers of PNS and SNS: NT and where they synapse
ACh for both
SNS: paravertebral or prevertebral ganglia - short
PNS: by effector organ - long
where does paravertebral ganglia connect to?
abdominal and pelvic organs
where does preavertebral ganglia connect to?
myenteric plexus
POSTganglionic fibers of PNS and SNS: what NT?
SNS: EP/NE, ACh - long
PNS: ACh - short
What NT binds to muscarinic receptors?
ACh
Adrenal medulla
sympathetic ganglia
NO postganglia –> direct release into blood
(80%EPI/20%NE)
What receptor does the SNS’s ACh bind to and what does it affect?
muscarinic –> sweat glands
What receptor does the SNS’s NE/EPI bind to and what does it affect?
nicotinic –> smooth muscles and glands
PNS same except ACh
Action of NE binding to Alpha 1 receptor
smooth muscle contraction
vasoconstriction
Action of NE binding to Alpha 2 receptor
inhibits NE release
insulin secretion
promotes blood clotting
Action of NE binding to Beta 1 receptor
HEART
increases HR and strength
stimulates renin release from kidneys
Action of NE binding to Beta 2 receptor
LUNG
dilates blood vessels and bronchioles,
relax smooth muscle: digestion, urination, uterus
What receptor does DA act on in ANS
alpha/beta/Da receptor agonist
Da is a precursor of what NT
EPI
Da effect in peripheral NS at low and high doses
low: vasodilation - Inc GFR in KIDNEYS
high: vasoconstriction - HEART; NE release
Da effect in CNS
pleasure, motivation
Serotonin effect in CNS
feeling of well-being
Where is 90% Serotonin produced in and what is its function?
enterochromaffin cells of the GI tract
increase GI motility
Acute serotonin syndrome
Hyperthermia
Agitation
Increased reflexes
Tremor, sweating, dilated pupils, diarrhea
vasomotor tone
constriction/dilation to vessel to maintain BP
ANS reflex - Baroreceptor (aorta and carotid sinus)
carotid sinus (CN9) and aorta (CN10) sense BP rise –> afferent –> efferent –> vasodilation
Visceral reflex of BP changes
baroceptors –> heart rate adjustment
What target organs are only innervated by sympathetic fibers?
Adrenal medulla, arrector pili muscles, some sweat glands & many blood vessels
SLUDGE = Parasympathetic effects on visceral organs***
salivation, lacrimation, urination, defecation, GI functions, emesis
mydriasis v miosis
mydriasis: pupil dilation
miosis: constriction
what does pilocarpine drug do in glaucoma?
act via muscarinic receptor
promote outflow of vitreous fluid to reduce intraocular pressure
What the enteric nervous system do?
Glandular secretion, blood flow, peristalsis
What heart node does SNS, PNS target?
SNS: SA
PNS: AV
MoA of ADRENOGENIC ANTAGONIST & SYMPATHOLYTIC
Inhibiting transport into synapses
Reduce Release from nerve terminal
Alpha blockers
Beta blockers
Where does sperm mature and store?
head of epididymis
store in tail
cremaster muscle
elevates testes
skeletal muscle
dartos muscle
contracts to pull scrotum upwards based on temp
gives scrotum wrinkled appearance
smooth muscle
raphe
ride between two halves of scrotum, perineum, penis
spermatic cord
vascular, nerve, lymph supply of testes and vas deferens
function of septum
so testes don’t wrap around one another
optimal temperature for sperm development
3-4C below body
91-93F
Cremaster and dartos muscles
tunica vaginalis
parietal and visceral layers of testes
tunica albuginea
capsule of testes
where is tunica vaginialis derived from?*
peritoneum prior to descent of testes
where does spermatogenesis occur?
seminiferous tubules
begins at puberty
blood testis barrier*
sertoli cells connected by tight-junctions
isolate sperm from rest of body
transport developing cells
sertoli cells
“mother” cells
leydig cells
in interstitial tissue of septum between seminiferous tubules
secrete testosterone, stimulated by LH
promote spermatogenesis
ejaculatory duct is composed of:*
vas deferens and duct of seminal vesicle (60%; fructose*)
prostate produces what percent of semen?
30% alkaline fluid: neutralize acidic fluid and support sperm
What does bulbourethral (Cowper’s) glands produce?*
pre-ejaculate: lubricate, flush out, neutralize urethra
What branch of nervous system causes tumescence*
parasympathetic
Sensory nerve supply of penis
pudendal –> deep perineal –> doral n.
What compound is involved in tumescence and what happens?
Nitric oxide: increases arterial flow
vein pinched off
What branch of nervous system causes detumescence
sympathetic
Arteries of spinal cord
(2) spinal a.
(1) radicular a.
(branches of vertebral)
Venous drainage of spinal cord
spinal and radicular v. (valveless to anastamose) –> int/ext vertebral plexuses –> systemic segmental v. and drual v. sinuses
conus medullaris
where spinal cord terminates at 2nd lumbar vertebra
filum terminale
fibrous tissue that attaches coccyx to vertebral bodies, anchors
from dura mater
layers of dura mater
endosteal
meningeal
dural sinus in between
arachnoid mater
avascular
csf in subarachnoid space (continue to S2)
denticulate ligament
lig from pia to dura
pia
very vascularized
patellar reflex dermatome
L4
Achilles dermatome
S1
Unbilicus
T10
Groin
L1
Rectum dermatome
S4, 5
Lateral horn
in thoracic spine only
innervate visceral and pelvic organs (heart, lungs, abs)
divisions of dorsal column
Gracile Fasciculus (T6 and up) Fasciculus Cuneatus (below T6)
causes of dorsal column damage
Syphilis, alcoholism, Vit B deficiencies, DM
ipsilateral
Spinothalamic tract
contralateral damage
Spinocerebellar tract
does not deccusate
unconscious proprioception: aware body position
ipsilateral damage
corticospinal tract*
conscious control of skeletal muscles on OPPOSITE side
crosses over at medulla
tracts responsible for subconscious control of balance, muscle tone, limb position
Vestibulospinal
Tectospinal
Reticulospinal
Rubrospinal
UMN syndrome
spastic
increase deep tendon reflex
pos babinski sign
LMN syndrome
flaccid paralysis
absent deep reflex
has superficial reflex
Rubrospinal
Sends information to flexor and extensor muscles
Tectospinal tract
reflex movements of head in response to visual and auditory stimuli
Reticulospinal tract
Sends information to cause eye movements and activate respiratory muscles
Vestibulospinal tract
Sends information from inner ear to maintain head position
what does autonomic reflexes have that skeletal muscles (somatic reflexes) not have?
pre/postganglionic fiber
ALS
UM and LM signs
atrophy, hyperreflexia, spasticity
Polio
attack anterior horn - paralysis
Guillain-Barre
attacks myelin sheath
sensory and lower motor neuron loss
Brown-Sequard syndrome
incomplete spinal cord lesion
from blunt trauma
1. ipsilateral loss of proprioception, vibration, position sense and
tactile discrimination
2. contralateral loss of pain and temperature sensation
below the level of lesion
