Week 1- Neuroanatomy Review Flashcards
PART 1: DEFINITIONS AND CNS HISTOLOGY
PART 1: DEFINITIONS AND CNS HISTOLOGY
- What makes up the CNS?
- What makes up the PNS?
- Brain and Spinal Cord
- EVERYTHING ELSE
Brain Orientation (above brainstem):
- Dorsal=_____
- Ventral=______
- Rostral=_______
- Caudal=________
- Dorsal=Top
- Ventral=Bottom
- Rostral=Front
- Caudal=Back
Brain Orientation (below brainstem w/ cerebellum):
- Dorsal=_____
- Ventral=______
- Rostral=_______
- Caudal=________
- Dorsal=Back
- Ventral=Front
- Rostral=Top
- Caudal=Bottom
Describe the 3 planes.
- Horizontal- divides into top and bottom
- Coronal- divides into front and back
- Sagittal- divides into L and R
What is the functional unit of the brain?
Neuron
What are the (5) parts of the Neuron?
- Soma
- Dendrites
- Axon Hillock
- Axon (myelin sheath and Nodes of Ranvier)
- Terminal Branches
What is the job of the dendrites?
Receive information from neighboring neurons.
What is the job of the soma?
Takes info from dendrites and organize it.
What is the job of the axon hillock?
Gateway to the axon, decides whether or not it wants to propagate signal (AP).
What is the job of the axon?
Myelin sheath crucial to act as insulator/conductor for the signal (increasing speed). AP jumps between Nodes of Ranvier.
What are the glial cells function?
Support cells to our neurons that help make them what they are.
What are the (4) types of glial cells?
- Oligodendrocytes
- Astrocytes
- Ependymal Cells
- Microglia
What is the job of the oligodendrocytes?
Create myelin (PNS equivalent=Schwann cells)
What is the job of the astrocytes?
Support cells, remove waste, regulate intracellular CA2+ levels
What is the job of the ependymal cells?
Lines ventricle walls, produces CSF
What is the job of the microglia?
Remove foreign bodies (Macrophages of CNS)
What is the biggest difference between oligodendrocytes and Schwann cells?
One oligodendrocyte can produce myelin at multiple cells along an axon and at multiple axons. One Schwann cell creates one area of myelinization.
Describe the (4) steps of Neural Communication.
- ) Presynaptic AP leads to opening of NT channels on axon terminal.
- ) Vesicles containing NTs release into synaptic cleft.
- ) NT binds with postsynaptic protein receptor.
- ) Receptors open, allowing NTs to enter post synaptic neuron and propagate another AP to travel down postsynaptic axon.
Action Potential:
- RMP=___mV
- Graded Potential can be up to ___mV
- Depolarization adds ______ charges which ______ the neuron.
- Hyperpolarization adds ______ charges which ______ the nueron.
- -70mV
- 15mV (either + or -)
- positive, EXCITE
- negative, INHIBIT
The action potential is a ____________ principle and will occur at ____mV.
- all or nothing
- -55mV
Signal Conductions depends on what (3) things?
- Fiber diameter
- Presence of myelin
- Thickness of myelin
-List the Fiber Types by Conduction Velocity and Fiber Diameter in order of speed (fastest to slowest).
Conduction Velocity:
-Aα, Aβ, Aγ, Aδ, B, C
Fiber Diameter:
-Ia, Ib, II, III, IV
PART 2: PERIPHERAL NERVOUS SYSTEM
PART 2: PERIPHERAL NERVOUS SYSTEM
The PNS is divided into what 2 parts? Explain each.
Somatic Nervous System:
- VOLUNTARY movement that has both a sensory (afferent) and motor (efferent) portion.
- Involves Spinal and Cranial nerves.
Autonomic Nervous System:
-INVOLUNTARY control of autonomic processes via sympathetic (arousing) and parasympathetic (calming) divisions.
The Somatic Nervous System is compossed of Cranial and Spinal Nerves which can be classified in what (3) ways?
- Motor
- Sensory
- Mixed
How many spinal nerves do we have?
31
- (8) Cervical
- (12) Thoracic
- (5) Lumbar
- (5) Sacral
- (1) Coccygeal
- What is the NMJ?
- What is the driving NT?
- Synapse between motor neuron and skeletal muscle fibers.
- ACh
What is a Motor Unit?
-A motor neuron and the skeletal muscle fibers innervated by its terminals.
The Autonomic Nervous System controls involuntary functions mediated by the activity of what (3) things?
- Smooth muscle fibers
- Cardiac muscle fibers
- Glands
The Autonomic Nervous System is controlled by what (4) structures?
- Limbic system
- Hypothalamus
- Brainstem/Reticular Formation
- Spinal Cord (T1-L2, S1-S3)
- Sympathetic = __________
- Parasympathetic = ___________
-Are sympathetic or parasympathetic responses longer lasting?
- fight or flight
- rest and digest
-sympathetic
- When a reflex arc consists of only two neurons, one sensory neuron, and one motor neuron, it is defined as ________ reflex.
- When one or more interneurons connect afferent (sensory) and efferent (motor) signals, it is defined as _________ reflex.
- monosynaptic
- polysynaptic
Which type of reflex provides rapid feedback on motor control?
Monosynaptic reflexes
Normally, the descending drive from the cortex on reflexes is __________.
inhibitory
PART 3: MENINGES, BLOOD SUPPLY, AND CSF
PART 3: MENINGES, BLOOD SUPPLY, AND CSF
What are Meninges?
3 layers that surround the brain and spinal cord that primarily function to protect and provide structural support.
What are the (3) layers and (3) spaces of the meninges from outside in?
- Epidural Space
- Dura Mater
- Subdural Space
- Arachnoid Mater
- Subarachnoid Space
- Pia Mater
- What is found in the subdural space?
- What is found in the subarachnoid space?
- bridging veins and interstitial fluid
- CSF
CNS Blood Supply:
- Our posterior circulation comes from the ________ artery.
- Our anterior circulation comes from __________ → _________
- Vertebral Artery
- Common Carotid Artery → Internal Carotid Artery
What are the branches of the Internal Carotid Arteries that provide Anterior Blood Supply?
- Opthalmic Arteries
- Posterior Communicating Artery
- Anterior Choroidal Arteries
- Anterior Cerebral Arteries (Anterior communicating and Recurrent artery of Heubner)
- Middle Cerebral Arteries (Lenticulostriate arteries)
The Anterior Blood Supply has nothing to do with the ________, only really supplies the _______.
- brainstem
- cortex
The Posterior Blood Supply comes from branches of the _______ and _________ arteries.
- Vertebral
- Basilar
What are the branches of the Vertebral Artery?
- Anterior Spinal Arteries
- Posterior Inferior Cerebellar Arteries
- Posterior Spinal Arteries
What are the branches of the Basilar Artery?
- Anterior Inferior Cerebellar Arteries
- Labyrinthine Arteries
- Pontine Arteries
- Superior Cerebellar Arteries
- Posterior Cerebral Arteries
The Posterior Blood Supply is where the _________ structures get their blood supply from.
Brainstem and Cerebellum
- What is the purpose of the Circle of Willis?
- What (4) structures make up the Circle of Willis?
-Provides opportunities for collateral blood flow, protecting from ischemia.
- Anterior Communicating Artery
- Anterior Cerebral Arteries
- Posterior Communicating Arteries
- Posterior Cerebral Arteries
A complete full-caliber ring is present in only __% of individuals.
34%
Anterior Cerebral Artery:
- The ACA travels in the ________ fissure above the ____________.
- It supplies the medial aspects of the _______ and _________ lobes.
- Deeper branches of the ACA go to the __________ and _______ regions.
- longitudinal, corpus callosum
- frontal and parietal
- basal nucleus and limbic regions
Medial Cerebral Artery:
- Supplies lateral ______, ________, and ______ lobes.
- Supplies medial and lateral _______ lobe.
- Also supplies ______ and subcortical structures such as what?
- lateral frontal, parietal, and occipital lobe
- medial and lateral temporal lobe
- insula; basal ganglia, internal capsule, limbic structures
- __________ arteries are tiny branches that come off of the MCA and are highly susceptible to what?
- What structures do they supply?
- Lenticulostriate Arteries, HTN
- Internal Capsule, Basal Ganglia
Posterior Cerebral Artery:
- What cortical structures are supplied by the PCA?
- What subcortical structures are supplied by the PCA?
- Medial and inferior Occipital Lobe, Inferior Temporal Lobe
- Midbrain, Subthalamus, Thalamus
What are the (4) largest branches that provide brainstem circulation?
- Posterior Inferior Cerebellar Artery (PICA)
- Anterior Inferior Cerebellar Artery (AICA)
- Superior Cerebellar Artery (SCA)
- Posterior Cerebral Artery (PCA)
- There is __ anterior spinal artery(ies) and __ posterior spinal artery(ies) that supply the spinal cord.
- The _________ spinal artery provides 2/3 of the vascularization of the spinal cord.
- 1, 2
- anterior
CSF is derived from blood plasma and is created in the ________ plexus by ________ cells.
- choroid
- ependymal cells
What are the (4) functions of the CSF?
- Buoyancy
- Protection
- Homeostasis
- Waste Clearance
- What is the normal total volume of CSF?
- What is the CSF production rate?
- 150cc
- 20cc/hour
What are the ventricles from top to bottom?
- Lateral Ventricles (anterior, posterior, inferior horn)
- Third Ventricle
- Cerebral Aqueduct
- Fourth Ventricle
- Central Canal (spinal cord)
PART 4: CEREBRUM AND BRAINSTEM
PART 4: CEREBRUM AND BRAINSTEM
What are the (4) lobes of the cerebrum?
- Frontal
- Parietal
- Temporal
- Occipital
What are the functions of the frontal lobe?
- Higher executive function including emotional regulation, planning, reasoning, attention, and problem solving.
- Primary and Supplementary Motor Regions
- Supplementary Speech Regions
What are the functions of the parietal lobe?
- Primary and Supplementary Somatosensory Regions
- Perceptual Integration (non-dominant)
- Visual Processing Regions (“where?”)
- Supplementary Speech Regions (dominant)
What are the functions of the temporal lobe?
- Primary Auditory Center
- Visual Processing Regions (“what?”)
- Memory
What are the functions of the occipital lobe?
-Primary Visual Center
All lobes have a _______ cortex.
Primary
- Frontal=Motor
- Parietal=Somatosensory
- Temporal=Auditory
- Occipital=Visual
___________ is a somatotopic arrangement of primary motor and sensory strips in the brain.
Homunculus
Association cortices can be divided into _______ or _________.
unimodal or heteromodal
___________ association cortexes are modality specific while ________ are higher-order mental functions.
- Unimodal
- Heteromodal
What are (4) unimodal association cortices?
- Motor Association Cortex (premotor and supplemental motor areas)
- Somatosensory Association Cortex
- Visual Association Cortex
- Auditory Association Cortex
Which hemisphere of the brain provides:
- Analytical thought
- Logic, reasoning
- Language centers
Which hemisphere of the brain provides:
- Perceptual integration
- Imagination
- Insight
- Intuition
- Creativity
- Emotional drive
- Left
- Right
What are the (3) parts of the brainstem?
- Midbrain
- Pons
- Medulla
What are some important structures of the midbrain and their functions?
- Superior colliculi- Receives info from environment and uses the info to initiate an appropriate behavioral response.
- Inferior colliculi- Role in hearing, where all auditory pathways travel through and converge.
- Red Nucleus- Motor function and coordination.
- Raphe Nucleus- Serotonin producing station.
- Ventral Tegmentum Area- Dopamine producing station.
- Pons is a “bridge” between the _________ and brainstem/cortex and acts as a relay station via the superior, middle, and inferior cerebellar __________.
- The pons makes up the floor of the ____ ventricle.
- cerebellum, peduncles
- 4th
The medulla plays an important role in __________ and ____________ function.
cardiovascular and respiratory
Where do 90% of corticospinal tracts cross in the medulla?
Pyramidal decussation
- Nucleus cutaneous function?
- Nucleus gracilis function?
- Receives sensory input about position and movement (proprioception) from the upper limb.
- Participates in the sensation of fine touch and proprioception of the lower body.
Cranial Nerve nuclei lie within the __________.
brainstem
Cranial Nerves and their function?
- I (Olfactory) = Smell
- II (Optic) = Visual Acuity, color discrimination, field cuts, pupillary response to light accommodation (II and III)
- III (Oculomotor) = Extra-ocular movement: elevation, depression, adduction, Pupillary response to light accommodation (II and III)
- IV (Trochlear) = Extra-ocular movement: Depression/intorsion
- V (Trigeminal) = Facial sensation, muscles of mastication, Corneal Reflex (V and VII)
- VI (Abducens) = Extra-ocular movement: abduction
- VII (Facial) = Muscles of facial expressions, secretomotor fibers to lacrimal and salivary glands, Corneal Reflex (V and VII)
- VIII (Vestibulocochlear) = Hearing, Vestibulo-Ocular Reflex (VOR)
- IX (Glossopharyngeal) = Palatal activation, Gag Reflex (IX and X)
- X (Vagus) = Visceral afferents, Gag Reflex (IX and X)
- XI (Spinal Accessory) = SCM and UTrap activation
- XII (Hypoglossal) = Tongue muscles
The ________________ maintains an alert conscious state in the forebrain via RAS. It works with CN nuclei and spinal cord to modulate important motor, reflex, and autonomic functions.
Reticular Formation
Does the reticular formation receive afferent or efferent input?
both afferent and efferent
PART 5: ASCENDING AND DESCENDING TRACTS, BASAL GANGLIA, CEREBELLUM
PART 5: ASCENDING AND DESCENDING TRACTS, BASAL GANGLIA, CEREBELLUM
What are the (6) ascending tracts?
- Dorsal Column/Medial Lemniscus
- Trigeminothalamic
- Spinothalamic
- Trigeminothalamic
- Spinoreticular
- Spinomesencephalic
Dorsal Column/Medial Lemniscus:
- The DCML contains the ______ tract (LE) and _______ tract (UE).
- What are the functions of this tract?
- What is the pathway of this tract?
- Where does it cross?
- gracile tract (LE) and cuneate tract (UE)
- light touch, discrimination, proprioception, kinesthesia, vibration
- Spinal Cord → VPL thalamus → Primary Somatosensory Cortex
- caudal medulla
Trigeminothalamic System:
- What are the functions of this tract?
- What is the pathway of this tract?
- Where does it cross?
- light touch, discrimination, proprioception, kinesthesia, vibration of face
- Spinal Cord → VPM thalamus → Primary Somatosensory Cortex
- medulla
Why do we not have facial sensation loss if we have a spinal cord stroke?
The trigeminothalamic tract enters at the level of the pons and is not at the level of the spine.
What are the (4) tracts of the anterolateral system?
- Spinothalamic
- Trigeminothalamic
- Spinoreticular
- Spinomesencephalic
The anterolateral system has what functions?
-pain, temperature, crude touch
- Spinothalimic = pain, temp, crude touch from ______.
- Trigeminothalamic = pain, temp, crude touch from _____.
- body
- face
The __________ tract involves the emotional and arousal aspects of pain.
spinoreticular
The ______________ tract is the central modulation of pain.
spinomesencephalic
What is the pathway of the anterolateral system?
-Spinal Cord → VPL thalamus → Primary Somatosensory Cortex
What structure is significantly important as a relay and processing station mainly for sensory info, but also motor inputs from the cerebellum and basal ganglia, limbic inputs, and reticular inputs?
Thalamus
What are the (4) Motor Subsystems?
- Segmental Circuits (spinal cord and brainstem)
- Descending Pathways (cortex and brainstem)
- Basal Ganglia
- Cerebellum
What are the (5) descending tracts?
- Corticospinal (lateral and anterior)
- Rubrospinal
- Vestibulospinal
- Tectospinal
- Reticulospinal
Corticospinal Tract:
- 90% of the corticospinal tract is the ________ corticospinal tract.
- Where does this tract cross?
- What is its function?
- lateral corticospinal tract
- crosses at the pyramidal decussation
- motor function of contralateral extremities
Corticospinal Tract:
- 10% of the corticospinal tract is the _________ corticospinal tract.
- Where does this tract cross?
- What is its function?
- anterior corticospinal tract
- does not cross
- motor function of BILATERAL axial and girdle muscles
Why is it important that the anterior corticospinal tract has bilateral function of axial and girdle muscles.
If you have a stroke on one side, axial and girdle muscles will be spared due to bilateral innervation.
Rubrospinal Tract:
- Where does this tract originate?
- Where does this tract cross?
- What is its function?
- red nucleus of midbrain
- midbrain
- motor function and tone regulation of contralateral extremities, particularly FLEXOR muscle groups
Vestibulospinal Tract:
- Function of the Medial VST?
- Function of the Lateral VST?
- Medial VST = positioning of head/neck
- Lateral VST = trunk control/balance
Tectospinal Tract:
- Where does this tract cross?
- What is its function?
- midbrain
- coordination of head and eye movements
Reticulospinal Tract:
- Where does this tract originate?
- Function of the Medial (Pontine) RST?
- Function of the Lateral (Medullary) RST?
- reticular formation
- Medial RST = axial and extensor motor neurons, postural support
- Lateral RST = flexor motor neurons
The basal ganglia is a group of structures deep in the cortex that include what (4) primary structures.
- caudate nucleus
- putamen
- striatum
- globus pallidus
What is the main function of the basal ganglia?
- Regulation of upper motor neuronal circuits.
- INITIATION and EXECUTION of movement, prevention of unwanted movement.
What are the additional roles of the basal ganglia?
- Goal-directed behavior loop
- Social behavior loop
- Emotion loop
The Cerebellum is separated into R/L hemispheres by the _________.
-vermis
What are the 3 lobes of the cerebellum?
- Anterior Lobe / Spinocerebellum
- Posterior Lobe / Cerebrocerebellum
- Flocculonodular Lobe / Vestibulocerebellum
What are the main functions of the cerebellum?
- Coordination (limb, trunk, occulomotor)
- Movement planning, control, and feedback
- Motor Learning
- Postural Control/Balance
- VOR Suppression
- Muscle Tone
PART 6: LIMBIC SYSTEM, VISUAL SYSTEM, VESTIBULAR SYSTEM
PART 6: LIMBIC SYSTEM, VISUAL SYSTEM, VESTIBULAR SYSTEM
What is the main thing the limbic system does?
Regulate emotion and memory.
Limbic system H.O.M.E pneumonic meaning and structures involved.
- H= Homeostasis (Hypothalamus)
- O= Olfaction (Olfactory Cortex)
- M= Memory (Hippocampal Formation)
- E= Emotion and Drives (Amygdala)
Hypothalamus functions H.E.A.L pneumatic.
- H= HOMEOSTASIS
- E= Endocrine control via pituitary gland
- A= Autonomic Control
- L= Limbic Mechanisms
What CN conveys visual information to the cortex?
CN II
What CN is responsible for pupillary response to light reflex?
CN II and III
What CNs are involved in extra-ocular eye movements and what movements do they do?
- CN III= up, down, medially; eyelid elevation
- CN IV= down and in
- CN VI= laterally
What are the (3) primary functions of the vestibular system?
- Stabilize visual images on the fovea of the retina during head movement to allow for clear vision
- Maintain postural stability, especially during movement of head
- Provide information for spatial orientation
What are the (3) key reflexes of the vestibular nuclei and their functions?
- Vestibulo-ocular reflex (VOR) = ability to keep eyes forward as head moves
- Vestibuospinal reflex (VSR) = in charge of anti-gravity muscles for postural adjustments
- Vestibulocollic reflex (VCR) = control head/neck relationship to the rest of the body
What are the (4) components of the central vestibular system?
- Vestibular Nuclei
- Vestibular Tracts
- Vestibulocerebellum
- Vestibular Cortex
What are the (3) regions of the vestibular cortex and their functions?
- Parieto-Insular Vestibular Cortex (PIVC) = recieves input from cerebellum and labyrinth, vestibular nuclei via the thalamus
- Medial Superior Temporal Region = visuo-vestibular integration and self-motion perception
- Ventral Intraparietal Region = Multisensory spatial coding; proprioceptive, auditory, visual, tactile
