Test 1 Flashcards
6 Functions of the Nervous System
- Perception
- Special senses: taste, balance, hear, vision, smell
- Somatosensory: group of modalitiles of body state; PainTouchProprioceptionTemperature
- Visceral: modulate, monitor, motivate - Movement
- plan, initiate, coordinate - Life sustaining
- seek, homeostais - Cognition
- memory, learning - Emotinon
- fear, pleasure, attatchment, desire - Arousal
- biological rythms; sleep, conciousness
4 Components of CNS
- forebrain (cerebral hemispheres and diencephalon)
- brainstem (midbrain, pons, medulla)
- cerebellum
- spinal cord
Components of PNS
- Sensory nerves: from periphery/viscera to CNS
- Motor nerves: commands from CNS to muscles/viscera
Subdivisons:
- Somatic Motor system: sensory nerve/motor nerves to skeletal muscles
- Autonomic Motor System: motor commands to viscera and smooth muscle via sympathetic, parasymphathetic, and enteric system
3 Primordial tissues
- Endoderm: epithelial of GI, respiratory, and urinary
- Mesoderm: muscle, skeletal, CT, and cardiovascular tissue, urogenital/hematopoietic systems, some microglia
- Ectoderm: skin, neurons, macroglia, ependymal cells (line ventricles), and some microglia
-Ectoterm transforms into neuroectoderm-> tubes to become chambers
Development of Chambers from 3-> mature
Prosencephalon->
- telencephalon-> cerebral hemispheres
- diecnephalon-> thalamus/hypothalamus
Mesencephalon->
-mesencephalon -> midbrain
Rhombencephalon->
- metencephalon-> pons/cerebellym
- myencephalon-> medulla
Flexures of Development
Cephalic flexure: during 3 vent stage, remains as secondary primary axis-> cererum/brainstem different axis
Cervical flexure: 3 vent stage; straightens out
Pontine flexure: marks beginning of cerebellar differentiation in 5 vent stage
Neuron anatomy:
INPUT zone
Soma and Dendrites
-dendrites increase surface area for synapse
Neuron anatomy:
INTEGRATION (trigger) zone
Axon Hillock
-“initial segment”
Neuron anatomy:
CONDUCTING zone
Axon
- neurofillaments skeleton of axons
- mircotubules allow protein transport to dendrites and terminal endings
Neuron anatomy:
TRANSMITTING zone
Presynaptic Terminal
“axon terminal”
Neuron anatomy:
INSULATOR
Myelin
-in schwann cells, oligodendrytes
Neuron anatomy:
AP Renewal/REGENERATOR
Nodes of Ranvier
Neuron anatomy:
TRANSMITTER RELEASE
Presynaptic membrane
- in axon terminal
- NT made here
Neuron anatomy:
TRANSMITTER UPTAKE
Postsynaptic membrane
-NT uptook here
3 Neuron Classification classes
- Morphology: multip, bi, uni, pseudounipolar
- Function: sensory, motor, autonomic, interneuron
- Neurotransmitter: chemicals they produce/release
4 Morphologic Classification of Neurons
- Psuedounipolar: DRG, somatosensation
- Unipolar: rare
- Bipolar: special senses
- Multipolar: almost all neurons
3 Glial Cell Functions
- Neuron growth: Support neuron growth/repair after damage
- Neuronal activity: Insulate axons/stabalize extracell activity
- Form glial systems: Chemical signaling in CNS
2 Classes of Glial Cells
- Macroglia: (astrocytes, oligodendrocytes, Scwann cells, ependymal cells)
- Astro/Oligo: CNS to many cells
- Schwann: PNS, myelinate ONE neuron at ONE location
- Emepndymal: line ventricles - Microglia: (few in number)
- increase when infections invade NS
3 Qualifications of NeuroTransmitters
- Pres-synaptic manufactored
- Calciam mediated release
- Receptors on post-synaptic bind to it
Functions of 5 Cerbral Lobe
Frontal: cognition, voluntary motor (speech)
Parietal: somatosensation, taste, intermodal (multisens) integration
Occipatl: vision
Temporal: hearing, speech recognitino, smell, memory formation
Insula: taste, emotive pain (2 long gyri 3 short gyri)
–Limbic (not lobe): homesotasis, olfaction, memory, emotion
Cranial Nerve Locations in Brainstem
2: rostral to midbrain- in diencephalon 3-4: midrain 5: pons 6-8: pondumedular junction 9-12: rostral medulla
Divisons of Spinal Cord Termination
Cauda equina: L1-L2 when spinal cord ends; roots
Conus Medullaris: T12-L1; tapering of SC
Filum Terminale: fibrous cord of pia mater anchoring to coccyx
Additional Set nerves T1-L3: forming pregranglionic nerves for sympathetic NS
Gray vs. White Matter
Gray: cell bodies forming nuclei/ganglia light in stains mantel of the cortex basal ganglia, hippocampal formation, amygdala
White: axons forming pathways dark in stains subcortical axon pathways to cortex pathways in/out of cortex
Diencephalon Composition
white vs. grey
- Nuclei with small pathways in/out of gray clusters
- Bound by large white matter traveling in/out cerebral hemispheres
Brainstem Composition
white vs. grey
- Gray matter in small, lose clusters of nuclei-> sesnory/motor nuclei and centers for integrative functions
- White matter travels between nuclei along outer portions brainstem
Spinal Cord Composition
white vs. grey
- gray central location; motor and interneurons for reflexes, autonomi symp neurons, and sensorimotor functions
- White matter around spinal gray; sensory/motor pathways for trunk/limb control; autonomic control of viceral function
3 Types of Axons
compose white matter pathways
- Projection fibers: long distances to different neural centers
- Commisural: cross midline and synpase contralaterally
(decussate) - Association fibers: project ipsilaterally to cortical areas
Cerebral Cortex Names
regarding number of layers
Neocortex: 6 layers (most)
Paleocortex: less than 6
Archicortex: 3 layers
Functions of 6 Neocortex Layers
I/II: axons and synapses; integrate activity within column
III: cell bodies of neurons projecting to other cortex areas (association)
IV: input zone into cortex; synapse on cell bodies in IV
V: cortical neurons projecting to nuclei of brainstem/SC
VI: axons projecting to thalamus
Brodman Areas Function
BA 1-3: postcentral gyrus
BA 4: Primary motor cortex; discrete selective motor control
BA 5,7: somatosensory association
BA 4,6,8: motor
BA 39-40: receptive language; inferior parietal lobule
BA 44, 45: speech
BA 3a
Muscle spindle and GTO input determine length and force generated
BA 3b
Merkel and Ruffini processed in slow adapting columns
Meissner and Pacinian processed in rapid adapting columns
Pain
BA 1
Combine sensory info from BA 3b and 3rd VPL neurons
Texture analysis
BA 2
Combine infor from BA 3a, BA 3b, and 3rd VPL neurons
Integrate hand proprioception with touch modalities; analyze shape, orientation, slip
BA 5
Somatosens Association Cortex
Combine BA 3, BA 1, BA 2
Sense activity on both sides of bofy via commissural fibers
Projects to motor cortex; helps form body schemas to coordinate body regions with itself
BA 7
Somatosens Association cortex
Info from all BA 5 areas and Vision!
Contributes to body schema in space
4 Primary groups of Commisural Fibers
Coordinate activities between L and R hemispheres; share info, modulate, integrate
- Corpus callosum
- anterior commissure
- Posterior commisure
- Hippocampal commissure
Structures on Midbrain
Ventral: cerebral peduncles, intrapenduncular fossa, CN III
Dorsal: superior/inferior colliculi, CN4
Structures on Pons
Ventral: CN V, basis pons, cerebellar peduncles
Dorsal: floor of 4th ventricle
Pontomed junction: CN VI, VII, VIII
Structures on Medulla
Ventral: pyramids, olives, anterior medial fissure, CN 9-12
Dorsal: obex, 4th ventrical (rostral), gracilis/cuneate tubercles and fissures, posterior septum, intermediate septum
Location of ventricles
Lateral: corpus/hemispheres Interventricular foramen: dienceph/corpus callosu 3rd vent: dienceph Cerebral aqueduct: midbrain 4th ventricle: pons/rostral medulla
Tectum vs. Tegmentum
Tectum: roof of midbrain/ventricular system
Tegmentum: anterior to ventricular structures in cross section(floor)
Cervical SC Characteristics
Dorsal Column: gracilis and cuneate w/ intermediate dorsal septum
Lateral Column: thick
Ventral Horn: extend laterally (for hands)
Thoracic SC Characteristics
Dorsal Column: only one
Lateral Horn: small in intermediate gray
Ventral Horns: small and narrow
Lumbar SC Characteristics
Dorsal Column: only one
No Lateral horn
Central Horns: large and extend more ventral
Sacral SC Characteristics
Dorsal Column: only one
Round Cross section
Columns: small (minimal white)
V/DH: relatively large compared to white
3 Menninge Layers
- Dura: tough outer layer
- lines skull
- 2 layers: periosteal/meningeal together except at fissures-> venous sinuses
- creates: cerebral falx (central), cerebellar tentorium (transverse fissure), cerebellar flax, and diaphragma sllae
- has own blood supply - Arachnoid: loose thin middle layer
- Pia: adheres to brain surface
3 Potential Spaces from menninge layers
- Epidural space: meningeal artery; bleed between skull and dura
- Subdural space: between dura and arachnoid
- Subarachnoid space: vessels enter/exit brain-> natural space
Primary CSF holder; trabechula stabalize each position
Anterior Cerebral Artery Supply
Supplies:
- anteromedial surface (frontal to parietal)
- superior medial structures along longitudinal fissure
- anterior caudate nucleus/fornix
Loss Causes:
- contralat limb weak/sensory loss
- frontal lobe behavior abnormalities
Anterior Choroidal Artery Supply
Off Internal Carotid
- posterior internal capsule
- globulus pallidus
- putamen
Posterior Cerebral Artery Supply
Supplies:
- medial temporal and occipital
- medial inferior/posterior cortical regions
- midbrain
- thalamus
Loss Causes: contralateral hemianopsia -sensory loss -hemiparesis -reading probs -aphasia
Middle Cerebral Artery Supply
Supplies:
- lateral surfaces of frontal/parietal
- temporal superior gyrus
- branches supplie basal ganglia, internal capsule (lenticulostriate arteries)
- lateral expanse cortex (corona radiata), internal capsule, putamen, gloubulus pallidus
Loss Causes:
- contralateral facial/arm weakness and sensory loss
- aphasia
- visual deficit
Vertebral Artery Supply
- medulla
- give post/ant spinal which supply caudal medulla and spinal cord
Basilar Artery Supply
- pons
- short circumfrential- ventral pons
- long circumfrential-dorsal/lateral pons
Cerebellar Artery Supplies
Superior: midbrain, superior cerebellum, rostral lateral pons, superior cerebellar peduncles
Posterior Inferior: lateral medulla, inferior cerebellum
Anterior Inferior: caudal lateral pons, cerebellum
Veinous Sinus System
Superior saggital: longitudinal fissure -> confluence of sinus
Inferior Saggital: above corpus collosum-> jugular vein
Transverse sinus: in transverse fissure-> confluence-
Confluence of sinus: superior, straight, and occipital sinuses join-> left/right transverse sinus-> sigmoid-> internal jugular-> heart
Why is somatosensation important?
- tissue protection/correct errors
- touch of objects
- interacting with environment
- coordination of fine motor movements
Muscle Spindles
In parallel with muscle fiber
- senses stretch and codes for amount
- fast receptors Ia, slow II fibers
Golgi Tendon Organs
free nerve endings interwoven within collagen of the tendon
- 1b fibers
- crimp by tendon collagen to code muscle contraction force
PNS meninge layers
Epineurium=dura; around spinal nerve
Perineurium=arachnoid; around nerve fascicle
Endoneurium= pia; around nerve fiber
3 Anteriorlateral Tracts
- Spinothalamic: pain/temp localization
VMp-insula (affective), VPL-SI (sens), MD-cingulate (emotive) - Spinomesencephalic: pain modulation
PAG-raphe nuclei-RexedII (seratonin modulates) - Spinoreticular: emotive aspects of pain/ANS modulation
Reticular formation in pons/medulla to cortex
Parabrachial nucleus to amygdala (fear and emotion)