Neuro anatomy Flashcards
What are the 3 divisions of the neuro system?
CNS, PNS, and ANS
Were does the germ layer of come from?
Embryonic ectoderm
What divides the central neural canal?
Sulcus limitans
What is the sensory area of the neural canale?
Alar plate
What is the motor area of the neural plate?
Basal plate
Is alar plate ventral or dorsal? Basal plate?
Alar: dorsal
Basal: ventral
What forms the autonomic ganglia, dorsal root ganglia, and adrenal medulla?
Neural crest
What are the 3 primary vesicles of the brain?
Prosencephalon
Mesencephalon
Rhombencepahlon
What are the secondary vesicles of the brain?
Telencephalon
Diencephalon
Mesencephalon
Metencephalon
Meyencephalon
What is the forebrain?
Telencephalon
Diencephalon
What is the midbrain?
Mesencephalon
What is hind brain?
Metencephalon
Myelencephalon
What parts are the anatomic brain?
Cerebelum and brainstem
What parts are the clinical brain?
Forebranin, midbrain, and hindbrain
What anatomical parts does the metencephalon contain?
Pons and cerebellum
What anatomical parts does the myelencephalon contain?
The medulla oblongata
Where is the lateral ventricle?
Telencephalon
Where is the third ventricle?
Diencephalon
Where is the mesencephalic aquaduct?
Mesencephalon
Where is the fourth ventricle?
Goes through metencephalon and myelincephalon
Metencephalon: foramina of Luschka
Meyelincephalon: foramina of Magendie
In the spinal cord, what does white matter originate from?
Marginal layer
In the spinal cord, what does grey matter originate from?
Mantle layer
In the spinal cord, what does the ependymal cells originate from?
Germinal layer
What is a large bundle of white matter called in the brain stem?
Funiculus
What is a small bundle of white matter called in the brain stem?
Fascicules
What are the sensory classifications?
GSA
SSA
GVA
SVA
GP
SP
What are the motor classifications?
GVE
SVE
GSE
What does the S and V mean in the classifications?
Somatic = Body structures
Visceral = Organ structures
What structures does the myelencepahlon have (including CN)?
Olive, pyramids, trapezoid body, and CN 6-12
What are the boundaries of the myelencephalon?
Rostral limit - trapezoid body
Caudal limit - first cervical spinal nerve
What is the trapezoid responsible for?
Auditory system
What are the pyramids responsible for?
Pyramidal motor system
What is the olive responsible for?
extrapyramidal motor system
What are the dorsal anatomical landmarks of the meyencephalon
Fasciculus gracilis: proprioception from pelvic
Fasciculus cuneatus: proprioception from thoracic
What is the caudal end of the 4th ventricle and the midpoint of the myelencephalon?
Obex
What is the sulcus limitans in the brain stem?
Where wall of 4th ventricle meets the floor
What are the boundaries of the metencephalon?
The transverse fibers of the pons
What cranial nerves are in the pons (metencephalic)?
V
What does the cerebellum do?
Coordinates motor activity with sensory information
What connects the cerebellum to the metencephalic?
Cerebellar puduncles (3 pairs - lateral, dorsal, and medial)
What is the rostral and caudal limits of the mesencephalon?
Diencephalon and metencephalon
What is on the ventral surface of the mesencephalic?
Crus cerebri - descending pyramidal motor pathway
Interpeduncular fossa - space between left and right crus cerebri
What cranial nerves are in the mesencephalic?
III and IV
What is on the dorsal surface of the mesencephalic?
Corpora quadrigemina (colliculus)
-Rostral colliculus: Visual reflexes
-Caudal colliculus: Auditory reflexes
What is the dorsal part of the mesencephalic?
Tectum
What is the ventral part of the mesecephalic?
Tegmentum
What are the 5 divisions of the diencephalon?
Thalmus
epithalmus
metathalmus
subthalmus
hypothalmus
What are the boundaries of the diencephalon?
Optic nerves
Mammillary bodies
What is the site of synapse for autonomic and emotions?
Mammillary bodies
What is the site of attachment for the pituitary gland?
Tuber cinereum
What cranial nerves are in the diencephalon?
II
What are where is the regulator of melatonin and circadian rythmn?
Pinneal body in epithalmus
What is the site of synapse in the auditory pathway?
Medial geniculate body - metathalmus
What part of the brain has olfactory bulb?
Telencephalon
What cranial nerves are in the telencephalon?
Olfactory
What are ridges and grooves of the cerebrum?
Gyrus and sulcus
What are the sulcus from medial to lateral on dorsal side of the spinal cord?
Dorsal median sulcus
Intermediate sulcus
Dorsolateral sulcus
What is the depression on the ventral side of the spinal cord?
Ventral median fissure
The spinal cord is shorter than the vertebral column, what is the site of termination for canine, equine, bovine, and feline?
Canine L5
Equine S1-2
Bovine L6
Feline L6
What is the end of the spinal cord called?
Conus medullaris
What are the fibers going off the conus medullaris called?
Cauda equina (tail of horse)
What is an example of a spinal reflex?
Leg kick
What is an example of a brainstem reflex
Blink reflex
What is a pathway with only one synapse?
Monosynaptic (rare)
How are signals sent through multiple spinal cord segments?
Interconnections via the interneuron
What is the purpose of the skin twitch test?
Can move along vertebrae and perform test, once area is reached without twitch, can confidently say there is a lesion around that vertebrae
What is the difference between conscious proprioception and subconscious proprioception?
Conscious: At rest
Subconscious: Moving
Describe fascicules gracilis pathway
Pelvic limb (DOG PAW FLIP ONE)
1st neuron: Dorsal root ganglion and ascends fascicules gracilis ipsilaterally
2nd neuron: Nucleus gracilis, ascends contralateral
3rd neuron: Ventral caudal lateral nucleus (VCL) of the thalamus and goes to sensory cortex
Describe dorsal spinocerebral tract
1st neuron - dorsal root ganglion
2nd neuron - Clark’s neuron and ascend ipsilateral and enter through caudal cerebellar peduncles, and end is cerebellum
Describe ventral spinocerebral tract
1st neuron - dorsal root ganglion
2nd neuron - immediately crosses contralaterally then enters rostral cerebellar peduncle and crosses contralaterally again
What is the clinical conscious deficit?
Knuckling
What is the clinical unconscious deficit?
Wide stance, wobbly, limbs swing out while moving
Describe the fasciculus cuneatus pathway
1st neuron - dorsal root ganglia and ascends ipsilaterally
2nd neuron - medial cuneate nucleus and crosses contralateral
3rd neuron - ventral caudal lateral nucleus and ascends to sensory cortex
Describe the cuneocerebellar tract
1st neuron - dorsal root ganglia and ascends ipsilateral
2nd neuron - lateral cuneate nucleus and enters cerebellar caudal peduncle
Describe the rostral spinocerebellar tract
1st neuron - dorsal root ganglia
2nd neuron - dorsal grey column and ascends ipsilateral and enters caudal AND rostral peduncle
Describe the spinal reflex arc
Monosynaptic or polysynaptic
Stimuli in, stimuli out
Describe the spinothalamic tract
Relay of nociception
1st neuron: dorsal root ganglia
2nd neuron: dorsal grey horn
axons cross contralateral
3rd neuron: within ventral caudal lateral nucleus then to sensory cortex
Describe the cranial reflex arc
Reflex of nociception in the head
1st neuron: trigeminal ganglion
2nd neuron: EITHER pontine sensory nucleus (mechanical) OR spinal nucleus of trigeminal nerve (thermo)
3rd neuron: Motor neuron of appropriate cranial nerve
Describe the quintothalamic tract
Relay of nociception to higher centers
1st neuron: trigeminal ganglion
2nd neuron: EITHER pontine sensory nucleus (mechanical) OR spinal nucleus of trigeminal nerve (thermal)
ALSO they go immediately contralateral
3rd neuron: Go to the ventral caudal lateral nucleus and then to sensory cortex
What are Lower motor neurons?
Neurons that make muscles contract
What are upper motor neurons?
Neurons that regulate lower motor neurons
Contained within CNS
What is the cortical motor system?
Pyramidal motor system
Highly skilled motor activity
What is the non-cortical motor system?
Extrapyramidal motor system
Stereotype of subconscious motor activity
What are the white matter structures of the upper motor system?
Corona radiata
Internal capsule
Crus cerebri
Longitudinal fibers of the pons
Pyramids
Axons
What are the tracts of the pyramidal system?
Corticonuclear system: cranial nerves 3-7 and 9-12 from pyrimidal to brainstem
Corticospinal system: from pyrimidal to spinal cord
>Lateral tract corticospinal: 75% will cross at pyramidal decussation
>Ventral corticospinal: 25% do not cross
What is the function of the cerebellum in the pyramidal motor system?
Smooth, coordinated functions
What way does the cerebellum send the smooth, coordinated functions (long word)
Coricopontocerebellar: Pyrimidal motor cortex to pontine nucleus for synapse at the pons. Then pass contralateral through peduncles into cerebellum
What is the area within the telencephalon with a large quantity of extrapyramidal motor nuclei?
Corpus striatum
What are the components of the lentiform nucleus? (gray matter)
Putamen nucleus
Pallidum nucleus
What is the most important extrapyramidal center in animals?
Rubrospinal tract (in later funiculus of the spinal cord)
What facilitates extensor muscles of the extrapyramidal system in the metencephalon
Pontine reticulospinal tract
What inhibits extensor muscles of the extrapyramidal system in the meyelencephalon?
Medullary reticulospinal tract
What are the 3 tracts that output the extrapyramidal signals (and their location) ***
Rubrospinal tract: Mesencephalic
Pontine reticulospinal: Metencephalic
Medullary reticulospinal: Myelencyphalic
What are the GSE neurons to extrafusal fibers?
Regular skeletal muscle fiber - alpha motor neurons
What are the GSE neurons to intrafusal fibers?
Modified skeletal muscle fiber - Gamma motor neurons
What are the 3 classification groups for cranial LMN neurons?
GSE - voluntary skeletal muscle
SVE - skeletal muscle of branchial arch origin
GVE - cardiac, glands, smooth muscle
Classification of cranial nerves! SSMMBMBSBBMM
Six sexy mommy milkers brought me boobs sex butts by milking me
What are the 4 GSE cranial nerves and nucleus location?
III - rostral colliculus
IV - caudal colliculus
VI - caudal cerebellar peduncle
XII - obex
In GSE of cranial nerves what do they innervate?
Extraocular muscles and lingual muscles
In SVE of cranial nerves what do they innervate?
skeletal muscle of branchial arch
In GVE of cranial nerves what do they innervate?
Visceral motor system, autonomic motor system
What are the cranial nerves of SVE plus their origin?
V - rostral cerebellar peduncle
VII - between trapezoid and olive
IX - nucleus ambiguus
X
XI
Important!!
GVE cranial nerve nuclei and their nerves form the ________
Autonomic nervous system
What are the generalized targets for parasympathetic and sympathetic innervation?
Smooth muscle, cardiac muscle, and glandular tissue
What is the function of the autonomic nervous system?
To respond to external stimuli
What controls the autonomic nervous system?
Rostral hypothalamus - parasympathetic
Caudal hypothalamus - sympathetic
How many neurons are used in the autonomic nervous system compared to the somatic nervous system?
2 fibers to targe vs 1 fiber to target
IMPORTANT!!
Preganglionic sympathetic fibers are
Postganglionic sympathetic fibers are
Preganglionic parasympathetic fibers are
Postganglionic parasympathetic fibers are
short
long
long
short
What are parasympathetic nuclei of cranial nerves?
III - edinger westfal
VII - lacrimal and rostral salivatory
IX - Caudal salivatory
X - dorsal vagal nucleus
