Midterm 1 Flashcards
(386 cards)
1
Q
What is neuroanatomy?
A
The study of the anatomy and organization of the central nervous system(s) of animals
2
Q
What are 2 examples of species that exhibit radial symmetry?
A
a) Hydra (cnidarian)
b) Sea star (echinoderm)
3
Q
What are 2 examples of species that exhibit bilateral symmetry?
A
Humans and drosophila
4
Q
What is the reference point that distinguishes dorsal and ventral called?
A
Cephalic flexure
5
Q
Describe neurons.
A
They convey information through electrical and chemical signals. They are the oldest and longest cells. It is the functional unit of behaviour. There is limited ability to be replaced
6
Q
Describe glia.
A
They provide a support system for neurons. They have a variety of types and functions. Their presence is crucial for neurons.
7
Q
Describe dendrite structure.
A
Tapered extension(s) of the cell body. Complex (branching)
8
Q
Describe the major organelles of dendrites.
A
Cytoskeleton and mitochondria
9
Q
What is the primary function of dendrites?
A
They are the primary site of reception
10
Q
Describe soma structure.
A
1 or more processes, generally 1 axon and many dendrites
11
Q
What are the major organelles of the soma?
A
Nucleus, ER and Golgi apparatus, Cytoskeleton, Mitochondria
12
Q
What are the primary functions of the soma?
A
Synthesis of macromolecules and integration of electrical signals
13
Q
Describe the structure of axons.
A
Single, cylindrical processes.
May have myelin.
14
Q
What are the major organelles of the axon?
A
Cytoskeleton, mitochondria, and transport vesicles
15
Q
What is the primary function of the axon?
A
Conduction of the action potential
16
Q
Describe the structure of the axon terminal.
A
Vesicle-filled opposed to another neuron
17
Q
What are the major organelles of the axon terminal?
A
Mitochondria and synaptic vesicles
18
Q
What is the primary function of the axon terminal?
A
Neurotransmission
19
Q
Which types of neurons have dendrites branching off of the axon?
A
Unipolar, pseudo-unipolar, and bipolar
20
Q
Which type of neurons have dendrites branching off the cell body?
A
Multipolar
21
Q
What is Golgi staining? Which chemicals does it use?
A
Silver staining technique for use under light microscope. Potassium dichromate and silver nitrate. Stains a limited number of cells at random
22
Q
What is immunohistochemistry?
A
Localization of proteins (antigens) using antibodies to specific proteins
23
Q
Which immunohistochemistry antibodies are used for neurons?
A
NeuN, MAP2, synaptophysin, PSD95
24
Q
Which immunohistochemistryantibodies are used for astrocytes?
A
GFAP (Glial fibrillary acidic protein)
25
What are the two detection methods for immunohistochemistry?
Chromogen and fluorescence
26
What is used for chromogen-based detection in immunohistochemistry?
Alkaline phosphate, horseradish peroxidase
27
What is used for fluorescence-based detection in immunohistochemistry?
FTIC, TRITC, Alexa Fluors
28
How does neuron filling work?
Via injection or axonal transport
Targeted filling of neurons of interest
Take advantage of polarity and transport mechanisms within the cell
29
What are some examples for neuron filling?
Biotin derivatives, GFP, lucifer yellow, viruses (pseudo-rabies/herpes)
30
What are some methods for loading in neuron filling?
Microinjection
Whole-cell patch clamping (in-vitro)
Electroporation
31
What are the defining features for glial cells?
Function to support neurons and are not electrically excitable
32
What are the 5 major types of glial cells? Where are each found?
```
Schwann cells (PNS)
Oligodendrocytes (CNS)
Astroglia (CNS)
Microglia (CNS)
Ependymal cells (CNS)
```
33
What is the ratio of glia needed per neuron?
1:1
34
Describe Schwann cells and their function.
Metabolic support. Wrap around individual axons in PNS to form the myelin sheath for electrical insulation. PNS axon regeneration.
35
Describe oligodendrocytes.
Myelinating cells of the CNS. Multiple processes allow one oligodendrocyte to surround multiple axons.
36
Describe astrocytes.
The most abundant glial cell in the CNS (75%). Mechanical support of neurons (scaffolding).
Metabolic support (glycogen) by communicating with blood vessels.
Regulation of extracellular fluid (K+, neurotransmitters).
Contact with CNS blood vessels.
Reactive astrocytes following injury/insult.
37
What % of glial cells is made up by microglia?
10-15%
38
Describe microglia.
Smallest glial cells.
Major role in CNS response to injury.
Survey for damage/disease.
Activated by inflammation, then transform to phagocytic macrophages
39
Describe ependymal cells.
They line the ventricular system of brain and central canal of spinal cord. Ciliated to aid movement of CSF. Where stem cells are born.
40
What kind of cell produces CSF and what is it called?
Ependymal cells. Choroid plexus.
41
What are gliomas?
Tumours in glial cells - 30% of all brain and CNS tumours.
| More specifically, one type is the astrocytoma.
42
What are some signs/symptoms of gliomas?
Headache, vomiting, seizures, personality changes, cranial nerve disorders, vision loss, pain, weakness, or numbness in extremities
43
What are 3 properties of ion channels?
Ion-specific, open/close in response to certain stimuli, and passive movement of ions down electrochemical gradients across membrane
44
What are the 3 types of ion channels?
Ligand-gated: open in response to binding of ligand (neurotransmitter)
Voltage-gated: open and close in response to changes in membrane potential (voltage)
Mechanical/stretch gated
45
What type of membrane do neurons have?
Semipermeable, polarized
46
What does the resting membrane potential range between?
-70 to -90 mV
47
How is the resting membrane potential generated?
The neuron has a semi-permeable, selective membrane (for K+ and Cl-) which is relatively impermeable to Na+.
K+ equilibrates based on electrochemical gradient (Ek).
RMP of most cells is about -70mV
48
When does the Na+/K+ ATPase kick in?
Over long-term (thousands of APs). Only required following sustained activity
49
What does the Na+/K+ ATPase do?
Actively transports 2K+ into cell and 3Na+ out of cell.
| Hydrolyzes ATP
50
How does the Na+/K+ ATPase affect water?
During AP, cells swell with water following Na+. The pump removes water by pumping out sodium.
51
Where does action potential propogation begin?
Propagation begins at the axon hillock
52
What are the 4 important properties of action potentials?
Threshold
All-or-none event
Conduction without decay
AP is followed by a refractory period
53
How are action potentials propagated over long distances?
Voltage-gated ion channels
54
What are the 4 phases of action potentials?
Threshold.
Depolarization: Open Vg Na+ channels.
Repolarization: Close Vg Na+ channels, Open Vg K+ channels.
Hyperpolarization Vg K+ still open.
55
What is the absolute refractory period?
Cell cannot respond to further stimulation.
| Inactivation of Na+ channels.
56
What is the relative refractory period?
Cell can respond, but requires a greater than normal excitation
57
What is the purpose of refractory periods?
Ensure APs only propagate in one direction
58
How does propagation work in unmyelinated axons?
Propagation is continuous. High number of Vg Na+ channels along entire length of axon.
Slow, about 1m/sec.
Conduction velocity is determined by axon diameter
59
How does propagation work in myelinated axons?
Propagation 'jumps' from one node to the next (i.e., saltatory conduction).
Vg Na+ channels at Nodes of Ranvier.
Fast, up to 100m/sec.
Conduction velocity determined by diameter of axon and myelin.
60
What are the three elements of the synapse?
Presynaptic ending, synaptic cleft, and postsynaptic element
61
What are the steps in synaptic transmission?
1. Production of neurotransmitters
2. Packing of neurotransmitters
3. Release of neurotransmitters
4. Binding to receptors
5. Termination of neurotransmitter action
62
What are the main types of neurotransmitters?
Small amines, amino acids, or neuropeptides
63
How are small molecule NTs synthesized?
Synthesized in the axon terminal by enzymes
64
Describe the synthesis of peptide NTs?
Peptide NTs are synthesized in the cell body and transported to the presynaptic endings.
Often synthesized as a larger precursor peptide
65
What are the major NTs in the small amine group?
Acetylcholine
Catecholamine (dopamine, norepinephrine)
Serotonin
Histamine
66
What are the major NTs in the amino acid group?
Glutamate
GABA
Glycine
67
What are the major NTs in the neuropeptide group?
```
Angiotensin II
Corticotrophin-releasing factor (CRF)
Endorphin
Enkephalin
Substance P
```
68
Describe small vesicles.
40nm in diameter
Contain small molecular transmitters
Located near the presynaptic membrane
69
Describe large vesicles.
>100nm in diameter
| Contain neuropeptide transmitters and sometimes small molecule transmitters
70
Describe how the release of neurotransmitters occurs.
1. Action potential arrives; triggers entry of Ca2+.
2. In response to Ca2+, synaptic vesicles fuse with membrane, release neurotransmitter.
3. Ion channels open when neurotransmitter binds, causes change in postsynaptic cell potential.
71
How do small vesicle NTs bind to receptors?
Diffuse rapidly across synaptic cleft, rapid binding to receptor
72
How do large vesicle NTs bind to receptors?
Slower release, more distance receptors, overall slower response
73
What is an example of rapid synaptic transmission?
Acetylcholine at nicotinic receptors
74
How does rapid synaptic transmission work?
NT binds to ligand-gated ion channels (Ionotropic).
Alters permeability of the postsynaptic membrane by opening or closing the channel.
Selectivity of the ion channel determines the postsynaptic effects.
75
What is an example of slow synaptic transmission?
Acetylcholine at muscarinic receptors
76
Describe slow synaptic transmission.
NT binds G-protein coupled receptor (metabotropic).
Binding of NT causes release of G-protein subunit which leads to altered concentrations of second messengers (prolonged effect).
2nd messenger binds to ion channel to alter permeability
77
What are four mechanisms for neurotransmitter termination?
Reuptake by presynaptic membrane or neighbouring glial cells.
Enzymatic inactivation.
Uptake by postsynaptic terminal.
Diffusion out of synaptic cleft.
78
What are some neurotransmitters that use reuptake to terminate action?
Serotonin, norepinephrine, dopamine
79
What is an example of enzymatic activation?
Acetylcholine by acetylcholinesterase (AChE)
80
What are gap junctions made up of?
Numerous connexons
81
What are the advantages of electrical synapses?
No delay in transmitting electrical information.
Useful for neurons that need to fire synchronously (i.e., respiration).
No need to synthesize vesicles or NTs.
82
What are the disadvantages of electrical synapses?
Loss of functional individuality - one cell's depolarization results in all cells depolarizing.
I.e., loss of "control"
83
What are the 3 germ layers? What do they form?
Endoderm - gut, liver, lungs.
Mesoderm - skeleton, muscle, kidney, heart
Ectoderm - skin and nervous system
84
How does the CNS form?
Induction of the ectoderm by the mesoderm to form neuroectoderm.
Neural plate -> neural tube.
Neural tube gives rise to brain and spinal cord (rostral and caudal respectively).
85
How does the PNS form?
From many diverse sources.
Neural crest cells.
Neural tube: preganglionic autonomic nerves and motor neurons.
Mesoderm: meninges and connective tissue surrounding peripheral nerves.
86
When does primary neurulation occur?
3rd-4th week of development
87
How does primary neurulation start?
Notochord (mesoderm) induces overlying ectoderm to differentiate into neuroectoderm
88
What is neurulation?
Induction of ectoderm to differentiate by mesoderm.
Development of the neural tube, running the length of the embryo.
Flat neural plate begins to fold forming paired neural folds.
Folds fuse together beginning in neck area and continues in both directions to form neural tube.
Cells on edge of neural plate form neural crest cells.
89
What is spina bifida?
Incomplete closure of caudal end of neural tube.
| Range in severity of defect.
90
What are the 3 types of spina bifida?
Occulta: -5% of population; incomplete closure of vertebrae.
Meningocele: pocket of CSF.
Myelomeningocele: most severe; spinal cord and meninges in sac-like cavity on back.
91
What is encephalocele?
Sac-like protrusion of brain and surrounding membranes
92
What is anencephaly?
Incomplete closure of the rostral end of the neural tube. Lack of telencephalon.
93
What are the 3 zones of the early neural tube? What is found in each of these regions?
Ventricular zone: Neural progenitor cells, neuroblasts and glioblasts.
Intermediate/Mantle zone: accumulation of neurons and glial cells; gray matter.
Marginal zone: cell poor neuronal and glia processes, white matter.
94
What is the sulcus limitans?
A division of the sensory and motor aspects of the spinal cord.
95
Where is the sensory portion of the spinal cord?
Dorsal portion -> alar plate
96
Where is the motor portion of the spinal cord?
Ventral portion -> basal plate
97
How do the spinal cord projections develop? From which aspect of the neural tube?
Motor neurons from basal plate send projections to muscle.
DRG sends projections both centrally and peripherally.
Caudal neural tube.
98
What are the 3 primary vesicles during early brain development?
Prosencephalon, mesencephalon, rhombencephalon
99
Which aspect of the neural tube develops into the brain?
The rostral end
100
What are the 5 secondary vesicles?
```
Telencephalon
Diencephalon
Mesencephalon
Metencephalon
Myelencephalon
```
101
Which vesicle grows at a greater rate than the others?
Telencephalon
102
What does the primary sulci form?
GW14-26
103
What is the corona radiata?
Radiating fibres that started in cortex and project to the thalamus and spinal cord
104
Where does proliferation of neural progenitors occur?
Ventricular zones
105
How do most neurons produced in the ventricular zone migrate?
Radially via somal translocation guided by radial glial cells
106
Which neuronal progenitors use tangential migration?
Medial and lateral ganglionic eminence.
| Inhibitory cortical interneurons.
107
When do the two important regressive events in brain development occur?
Neuronal populations lost prenatally.
| Glial populations lost postnatally.
108
Why does apoptosis occur in the nervous system prenatally?
Up to 70% of neurons are lost in some cortical areas.
May be a mechanism for correcting errors.
Eliminates transient cell populations (i.e. marginal zone and subplate)
109
Why does apoptosis occur in the nervous system postnatally?
Loss of excess oligodendrocytes during myelination
110
Describe synaptic exuberance and pruning.
Massive production of synaptic connections followed by the loss of up to 50% of synapses.
Largely postnatal, over months or years.
Mechanisms: neurotrophic support, afferent input
111
Why can't we remember life as a baby?
Hippocampal neurogenesis.
Excessive 'rewiring' of connections ('plasticity').
Hippocampus is still growing during childhood
112
Where do neural crest cells develop from? Why are they special?
They develop from cells on lateral aspect of neural plate.
Highly proliferative.
Differentiate into a number of neural and non-neural tissues.
Migrate throughout the embryo.
113
What are the two types of neural crest cells?
Cranial and trunk
114
What is the role of the dorsal root ganglion? What does it synapse with?
Provides sensory information from the body.
| Synapse with sensory neurons within dorsal horn.
115
How many neurons are involved in the 2 neuron system?
Preganglionic and postganglionic
116
Describe the preganglionic and postganglionic neurons of the sympathetic nervous system.
Preganglionic: Basal plate (motor) at thoracic and lumbar level.
Postganglionic: Neural crest derived neurons with cell bodies in sympathetic chain ganglia (close to spinal cord).
117
What is the exception of the pre- and postganglionic neurons in the SNS?
Chromaffin cells of adrenal medulla, neural crest derived
118
Describe the preganglionic and postganglionic neurons of the parasympathetic nervous system.
Preganglionic: Basal plate (motor) of brain stem and sacral level
Postganglionic: Neural crest derived neurons with cell bodies close to the organs of innervation
119
What are neurocristopathies?
A diverse class of pathologies involving cells derived from the neural crest
120
What is Waardenburg Syndrome?
A neurocristopathy involving pigment cells
121
What is neurofibromatosis?
A neurocristopathy involving masses of neurons/glia
122
What is cleft lip/palate?
A neurocristopathy involving cartilege/bone
123
What is unique about the Leopard gecko?
Can regenerate a functional tail following tail loss
124
What happens after axon transection in the PNS?
Wallerian degeneration occurs proximal to cut, Schwann cell proliferation, and increased RNA synthesis in neuron.
Schwann cells don't allow for scars
125
Where does adult neurogenesis occur?
Ependymal cells in the subgranular zone of the hippocampus and the subventricular zone of lateral ventricles
126
What happens after axon transection in the CNS?
Wallerian degeneration occurs proximal to cut. Astrocytes and oligodendrocytes actively impede regeneration.
127
What are glial scars?
Reactive astrocytes secrete chondroitin sulfate proteoglycans (CSPGs)
128
What are the 2 major connective tracts between hemispheres?
Corpus callosum and anterior commissure
129
Which brain areas does the corpus callosum connect?
Most cortical areas
130
Which brain areas does the anterior commissure connect?
Connection between temporal lobe cortical regions
131
What are sulci?
Depressions or grooves
| Deep sulci are called fissures
132
What are gyri?
Ridge or fold between two sulci
133
What are important features of sulci and gyri?
Increase the surface area of cortex/cerebrum
| Provide important landmarks
134
What are the 4 major sulci?
Lateral surface: central sulcus (of Rolando) and lateral sulcus/Sylvian fissure
Medial surface: parieto occipital sulcus and cingulate sulcus
135
How are gyri named?
Gyri are named in relation to the sulci they are beside
Example: precentral gyrus vs. postcentral gyrus, superior, middle, and inferior frontal gyrus
Correspond to functional areas
136
What are the 5 lobes of the cerebrum?
Frontal, parietal, occipital, temporal, and limbic
137
What functional areas are found in the frontal lobe?
Motor functions: precentral gyrus contain primary motor cortex.
Broca's area: production of written and spoken language
138
What functional areas are found in the parietal lobe?
Somatosensory information: postcentral gyrus contains primary somatosensory cortex
139
What functional areas are found in the occipital lobe?
Vision: contains primary visual and association cortices
140
What functional areas are found in the temporal lobe?
Superior temporal gyrus: primary auditory cortex.
| Wernicke's area: comprehension of language
141
Which structures make up the limbic system?
Telencephalon/cerebral structures: cingulate gyrus and parahippocampal gyrus, hippocampus, amygdala
Diencephalon structures: thalamus, hypothalamus
142
What is the role of the limbic system?
Role in emotional responses and memory
143
What nuclei make up the limbic system?
Amygdala and hippocampus
144
Which structures make the basal ganglia?
Globus pallidus, caudate, and putamen
145
Which structures make up the diencephalon?
Thalamus and hypothalamus
146
What is the role of the basal ganglia?
Roles in eye movement, motivation, and working memory
147
What is the internal capsule?
Fibres interconnecting cerebral cortex to thalamus and basal ganglia
148
What is the role of the thalamus?
Gatekeeper to the cortex.
| All sensory information (except olfactory) passes through thalamus
149
What is the role of the hypothalamus?
Autonomic nervous and neuroendocrine control
150
What is the role of the pineal gland (or epithalamus)?
It is an endocrine gland that produces melatonin
151
What does the brainstem consist of?
Midbrain and hindbrain (pons and medulla)
152
What are the main functions of the brainstem?
Attachment for most cranial nerves (cranial nerve reflexes), long tract functions, and ascending reticular activating system (for consciousness)
153
How is the cerebellum longitudinally divided?
The vermis splits the two cerebellar hemispheres
154
What are the 3 lobes of the cerebellum?
The anterior, posterior, and flocculonodular
155
What is the oldest lobe of the cerebellum?
The flocculonodular lobe
156
What are the functions of the cerebellum?
Coordination of trunk and limb movements and eye movements
157
What are the three layers of the meninges (from outermost to innermost)?
Dura mater, arachnoid mater, pia mater
158
What is the purpose of the meninges?
Provide mechanical support of the CNS
159
Which space surrounding the spinal cord is filled with cerebrospinal fluid?
The subarachnoid space
160
Describe dura mater?
Thick, touch, collagenous membrane. Fused with the endosteum (inner periosteum) of the skull. Adheres to underlying arachnoid.
161
What are the two dural septa/folds?
Falx cerebri and tentorium cerebelli
162
Are there spaces on either side of the dural membrane?
Not usually, but there are a few exceptions
163
Where are the two potential spaces around the dural membrane?
Epidural: between cranium and outer dural space.
Subdural: within innermost dural layer, near arachnoid border
164
What are the venous sinues contiained within the dura mater?
Superior saggital sinus, left and right transverse sinuses, and straight sinus
165
Describe the arachnoid mater?
Thin, avascular membrane in direct contact with dura mater
166
What is arachnoid trabecula?
Small strands of collagenous connective tissue within subarachnoid space, which give arachnoid mater its spider web-like appearance
167
What is arachnoid villi?
Small protrusion through dura mater into venous sinuses which allow for reabsorption of CSF into the venous system
168
What are subarachnoid cisterns? List the 4 major cisterns.
Large pockets of subarachnoid space filled with CSF.
| Interpeduncular, pontine, quadrigeminal, and cisterna magna
169
Describe pia mater.
"Tender" mater. Thin, connective tissue layer in direct contact with surface of CNS. Contact with arachnoid trabecula on either side. Cerebral arteries and veins are surrounded by pia before entering/exiting the brain (known as perivascular space)
170
Describe the three important differences in the meninges at the level of the spinal cord.
1. Vertebral canal contains an epidural space between the periosteum and dura.
2. Pia mater gives rise to longitudinal denticulate ligaments which are spinal cord anchors.
3. Lumbar cistern at caudal end of spinal cord.
171
Describe the lateral ventricles.
2 paired, C-shaped structures. 5 parts: frontal, occiptal and temporal horns, body, and atrium
172
Which structures border the thalamus and hypothalamus?
Third ventricle
173
Where is the fourth ventricle located? What does it communicate with?
Located in the hindbrain "space" between cerebellum and pons/medulla. Communication with subarachnoid space via 3 apertures (recess).
174
What structure produces CSF? Where is it found?
Lines lateral ventricles, passes through IV-foramen and roof of 3rd ventricle. Separate strand in 4th ventricle. Component of BBB
175
Describe the choroid plexus.
Specialized area where ependymal cells and pia mater are in direct contact. Specialized ependymal cells form the choroid epithelium with apical surface tight junctions.
176
Describe the surface area of the choroid plexus.
Increased surface area through folding. Total surface area is greater than 200cm^2.
177
How fast is the choroid plexus formed?
350 uL/minute
500 mL/day
Relatively constant
178
What is hydrocephalus?
"Water on the brain".
CSF is constantly produced.
Excess CSF production. Blockage of circulation. Deficient CSF reabsorption.
Causes enlargement of ventricle and compression of brain tissue.
179
What are the symptoms of hydrocephalus?
Headache, vomiting, nausea, papilledema, sleepiness, coma
180
How do you treat hydrocephalus?
Placement of shunt
181
Why is brain circulation important?
Neurons lack the ability to store energy and oxygen.
Brain uses about 15% of normal cardiac output.
Consumes 25% of the body's oxygen.
Loss of consciousness after just 10 seconds without perfusion.
182
Describe the internal carotid arteries.
Branch of common carotid arteries. Bifurcates into middle and anterior cerebral arteries. Blood supply for most of the cerebrum.
183
Describe the vertebral arteries.
Branch of subclavian arteries. Fuse at pontomedullary junction to form basilar artery. Branches form posterior cerebral artery and multiple cerebellar arteries. Blood supply for brainstem, parts of cerebrum and spinal cord.
184
Describe the Circle of Willis. What is it made up of?
Connection between internal carotid and vertebral-basilar arterial systems.
Posterior communicating artery: ICA to PCA
Anterior communicating artery: connects ACA branches
185
What happens if a major vessel within or proximal to the circle of Willis becomes occluded?
The communicating arteries allow for perfusion of distal tissue (also known as collateral perfusion). Most effective when occlusion occurs slowly over time.
186
Which areas does the ACA supply?
Medial surface of frontal and parietal cortices, corpus callosum
187
Which areas does the PCA supply?
Temporal cortex and some occipital cortex
188
Describe the MCA.
60-80% of blood flow from internal carotid artery. Upper division: frontal and parietal cortices
Lower division: temporal and occipital cortices
189
Describe the AChA.
Branch of the internal carotid artery.
| Blood supply of optic tract, choroid plexus of inferior lateral ventricle, thalamus, and hippocampus
190
Describe the perforating (ganglionic) branches.
Small branches off of ACA, MCA, or PCA.
| Blood supply of basal ganglia, internal capsule, and diencephalon.
191
Which branches are often compromised during stroke?
Perforating (ganglionic) branches
192
Describe the PChA.
Branches of the posterior cerebral artery. Supply choroid plexus of lateral and 4th ventricle.
193
Describe the AChA.
Branch of the internal carotid artery.
| Blood supply of optic tract, choroid plexus of inferior lateral ventricle, thalamus, and hippocampus
194
Describe the perforating (ganglionic) branches.
Small branches off of ACA, MCA, or PCA.
| Blood supply of basal ganglia, internal capsule, and diencephalon.
195
Which branches are often compromised during stroke?
Perforating (ganglionic) branches
196
Describe the PChA.
Branches of the posterior cerebral artery. Supply choroid plexus of lateral and 4th ventricle.
197
Which artery supplies blood to the midbrain?
Posterior cerebral artery
198
Which arteries supply blood to the pons?
AICA, SCA, along with multiple pontine arteries
199
Which arteries supply blood to the medulla?
PICA, along with anterior and posterior spinal arteries
200
Which arteries supply blood to the cerebellum?
3 cerebellar arteries: AICA, PICA, and SCA
201
How many sets of veins drain the brain? What are they called?
2: superficial and deep veins
202
Where are the superficial veins, and where do they drain to?
Lie on the surface of cerebral hemispheres and drain to superior sagittal sinus
203
Where are the deep veins, and where do they drain to?
The deep veins drain structures in the walls of the ventricles. They converge on internal cerebral veins and drain to the straight sinus
204
Which sinuses drain into the transverse sinuses?
Sagittal and straight sinuses
205
Where does the transverse sinus drain to?
Transverse sinus -> Sigmoid sinus -> Internal jugular vein
206
Which types of vascular problems are more common?
Arterial problems
207
What is the normal blood flow per minute to the brain?
55mL/100g brain per minute
208
Which 3 major mechanisms regulate blood flow to the brain?
Autoregulation: blood vessels constrict/relax to maintain constant flow.
Local responses: for example, Glu release from neurons which binds to astrocyte receptors and releases vasodilators to locally increase blood flow.
Autonomic control: may play a role in longer term adaptations but is the least important.
209
What is an angiography?
Injection of a radiopaque dye into the artery of interest, followed by radiographic imaging every 1-2 seconds. Identifies vascular pathologies such as aneurysms
210
What are the 3 types of strokes?
Ischemic stroke: sudden blockage of blood flow; damage can be limited to affected areas by early treatment.
Transient ischemic attack (TIA)/mini-stroke.
Hemorrhagic stroke: arterial rupture often of small perforating arteries.
211
Where are aneurysms most often formed?
At or near arterial branch points
212
What are the consequences of aneurysms?
Compression of brain tissue.
| Rupture = subarachnoid hemorrhage
213
What is the most common cause of neurological deficits?
Cerebrovascular accident/stroke that leads to a reduction of blood flow and neuronal malfunction or death
214
What is the arachnoid barrier?
The outermost layer of the BBB that prevents diffusion into subarachnoid space from outside the CNS
215
What is the intracerebral capillary?
A capillary that separates extracellular space of CNS from that of the rest of the body
216
What is the choroid epithelium?
The innermost layer of the blood brain barrier that regulates the composition of CSF/flow of components to/from plasma
217
What are circumventricular organs?
Locations where the cerebral capillaries are fenestrated and allow for relatively free communication
218
Where are CVOs located?
Around the 3rd and 4th ventricles
219
What are the two types of CVOs?
Sensory organs and secretory organs
220
What are the three sensory circumventricular organs? What are their functions?
Area postrema: monitors blood for toxins, induces vomiting
Vascular organ of the lamina terminalis (OVLT): regulation of fluid balance
Subfornical organ: fluid regulation
221
What are the secretory circumventricular organs? What are their functions?
Median eminence of hypothalamus and posterior pituitary: neuroendocrine role.
Pineal gland/epithalamus: secretion of melatonin
222
What is the role of primary sensory afferents?
Receive information about sensory input (touch, position, etc.)
223
Where are the cell bodies of primary sensory afferents?
In the sensory ganglia (i.e., dorsal root ganglion)
224
How do the primary sensory afferents run within the body?
The receptive ending, cell body, and central terminals all run on the same side of the body (IPSILATERAL)
225
Where are the lower motor efferent neuron cell bodies found?
In the CNS (specifically, the ventral horn)
226
What is the homunculus?
A distorted map of the body within the somatosensory cortex. A distorted body map is also seen in the motor cortex (or precentral gyrus) with an emphasis on face and hands
227
Where do UMNs originate?
The precentral gyrus
228
How do somatosensory pathways to cerebral cortex travel?
Pathways to the cerebral cortex cross the midline before reaching the thalamus so they reach the opposite cerebral hemisphere (CONTRALATERAL). The pathways stay on the same side from the cerebral hemisphere to the cerebellum
229
What is the homunculus?
A distorted map of the body within the somatosensory cortex
230
How do UMNs and LMNs interact?
UMNs from cerebrum influence the activity of LMNs
231
How do the UMNs of the corticospinal tract travel?
They cross the midline between the cerebral cortex and limbs to influence the CONTRALATERAL muscle
232
What is the corona radiata?
UMNs of the corticospinal tract
233
What does the corona radiata become as it goes through the thalamus?
The internal capsule
234
Where does the spinal cord travel?
From the brain stem to vertebral level L1/L2 where it ends at the conus medullaris
235
How many cervical segments of the spinal cord are there?
5
236
How many thoracic segments of the spinal cord are there?
12
237
How many lumbar segments of the spinal cord are there?
5
238
How many sacral segments of the spinal cord are there?
5
239
How many coccygeal segments of the spinal cord are there?
1
240
What is the cauda equina?
Collection of nerve roots (L3-S5) caudal to the conus medullaris
241
What are the 3 major pathways of the spinal cord?
Ascending sensory, descending motor, and reflex arcs
242
What is the function of the spinal cord?
Home to all lower motor neurons.
| Receives majority of sensory information.
243
What are dermatomes?
Functional areas supplied by spinal segment
244
What are somites?
During development, nearby mesoderm segments become somites. Spinal segments retain connectivity with nearby somite. These somites differentiate into cartilage, muscle, bone, skin, etc.
245
What are the 2 spinal enlargements and where are they located?
Cervical (C5-T1) and Lumbosacral (L1-S2)
246
What is the purpose of the lumbosacral enlargement?
Expansion in grey matter needed to innervate arms and legs (anterior horn)
247
What is the purpose of the cervical enlargement?
More white matter in higher spinal cord = more sensory/motor information passing through (funiculi)
248
What happens at the ventral (anterior) horn?
Ventral rootlets leave -> coalesce to form ventral root
249
What happens at the dorsal (posterior) horn?
Projections in dorsal root ganglion (cell bodies) -> divide into dorsal rootlets and enter cord
250
What are spinal nerves?
Coalescence of ventral and dorsal roots from a given spinal segment
251
Where is nerve root compression most common?
Lower cervical and lower lumbar regions
252
What are the symptoms of nerve root compression?
Pain in muscle innervated by spinal nerves affected.
Paraesthesia (numbness or tingling) in affected dermatome(s).
Loss of cutaneous sensory information.
Motor weakness.
Possible loss of spinal reflex (segment dependent)
253
What are treatments for nerve root compression?
Pain management, traction, surgery
254
What are the 5 sulci of the spinal cord?
Dorsal median sulcus.
Dorsal intermediate sulcus (cervical and upper thoracic).
Dorsolateral sulcus (entry of dorsal roots).
Ventrolateral sulcus (exit of ventral roots).
Ventral medial fissure (location of anterior spinal artery).
255
What are funiculi?
Regional divisions of spinal cord white matter that contain ascending and descending nerve tracts
256
What fasciculi comprise the dorsal funiculus?
Gracile (dorsomedial) and cuneate (dorsolateral)
257
What are the 3 funiculi?
Dorsal, lateral, and ventral
258
What is the function of the posterior horn (PH)? Which structures are found in it?
Sensory processing.
Lissauer's tract: entry of some DRG fibres.
Substantia gelatinosa: at superficial zone of PH; synapses of sensory afferents
259
What does the intermediate gray contain?
Interneurons and tract cells, and some autonomic motor neurons (preganglionic)
260
What does the anterior horn (AH) contain?
Motor neurons. All LMN cell bodies are here
261
How can gray matter be divided?
By cell type and function.
262
Which spinal cord regions are associated with which Rexed laminae?
Dorsal horn: I-VI
Intermediate gray: VII
Ventral horn: VII-IX
Central canal: X
263
How is the dorsal horn organized?
Sensory axons separate based upon their classifications and enter the dorsal horn via 2 separate streams
264
Describe the medial stream of the dorsal horn. Which Rexed laminae is it associated with?
Large, unmyelinated fibres. Touch and position.
Type I and II mechanoreceptors.
Rexed laminae II-VI
265
Describe the lateral stream of the dorsal horn. Which rexed laminae is it associated with?
Small fibres. Pain and temperature.
Adelta and C nociceptors, thermoreceptors, mechanoreceptors, and visceral afferents.
RL I-V
266
How is the ventral horn organized?
```
Topographically.
Each column supplies a group of muscles with a similar function.
Medial = trunk
Midregion = proximal limbs (arms)
Lateral = distal limbs (legs)
Extensors are anterior to flexors
```
267
Where are long, ascending fibres of the spinal cord travelling?
Spinal cord to thalamus, cerebellum, and brainstem
268
Where are long, descending fibres of the spinal cord travelling?
Cerebral cortex and brainstem to the spinal cord
269
Where do local propriospinal fibres travel and what are they important for?
Shorter fibres that interconnect different segments of spinal cord. Particularly important for spinal reflexes
270
What are reflexes?
Involuntary, stereotyped responses to sensory inputs
271
What does a reflex arc involve?
A receptor, associated afferent neuron and an ipsilateral efferent neuron. Many involve one or more interneurons.
272
Can upstream CNS signaling play a role in reflexes?
Yes
273
How many neurons does a descending spinal tract contain?
2
274
How many neurons does an ascending spinal tract contain?
3
275
What are the major tracts of focus?
Ascending: Posterior (dorsal) column-medial lemniscal (DCML) and spinothalamic tract.
Descending: lateral corticospinal tract
276
Describe the 1st order neuron of ascending tracts.
Primary sensory afferent.
The neuron that is in contact with or contains the receptive field.
Cell body is always contained within the dorsal root ganglia.
277
Describe the 2nd order neuron of ascending tracts.
Projection neuron with cell body inside the spinal cord or brainstem.
Receives sensory information from incoming primary afferent.
Projects to contralateral thalamus or ipsilateral cerebellum.
278
Describe the 3rd order neuron of ascending tracts.
Projection neuron with cell body located in thalamic nuclei.
| Axon projects to the somatosensory cortex (postcentral gyrus)
279
What information does the DCML pathway primarily contain?
Touch and positional information
280
Describe the primary afferents of the DCML pathway.
Large diameter alpha fibres.
Posterior column is divided at cervical/thoracic levels: Fasciculus gracilis (lower body) and fasciculus cuneatus (upper body).
Synapse in nucleus gracilis or cuneatus in caudal medulla
281
Describe the secondary afferents of the DCML pathway.
Secondary axons decussate in medulla, forming the medial lemniscus.
Synapse in ventral posterolateral (VPL) nucleus of the thalamus.
282
Describe the tertiary afferents of the DCML pathway.
Tertiary axons project to somatosensory cortex that is ipsilateral to the thalamus.
283
What information does the spinothalamic pathway primarily contain?
Pain and temperature
284
Describe the primary afferents of the spinothalamic tract.
Small diameter C and delta fibres. Synapse in ipsilateral dorsal (posterior) horn
285
Describe the secondary afferents of the spinothalamic tract.
Decussate at all levels of the spinal cord and travel through lateral funiculus.
Synapse in contralateral VPL.
286
Describe the tertiary afferents of the spinothalamic tract.
Project to somatosensory cortex and other cortical regions
287
What is the role of the cerebellar tracts?
Role to compare the movements that are being made to the movements the CNS thinks it should be making and correcting as needed. Requires proprioceptive information from spinal cord
288
What are the 2 main cerebellar pathways? What information do they carry?
Spinocerebellar: ipsilateral info about legs
Cuneocerebellar: ipsilateral info about arms
289
What neurons are contained within the 2 neuron descending tracts?
UMNs: Cell body within motor cortex (precentral gyrus).
LMNs: Cell body in spinal cord, and axons project to target organ/muscle.
Involves both somatic and autonomic control
290
Describe the UMNs of the lateral corticospinal tract.
Cell bodies in precentral gyrus and surrounding tissues. Bypass the thalamus via internal capsule and cerebral peduncles.
Decussate in pyramids.
Travel through lateral funiculus to synapse on contralateral LMN
291
Describe the LMNs of the lateral corticospinal tract.
Cell body in ventral horn of spinal cord. FIbres project to ipsilateral muscle
292
Describe the reticulospinal tract.
Two branches: pontine and medullary.
| Involvement in locomotion and posture control.
293
Describe the tectospinal/olivospinal tract.
Orientation of head towards source of visual or auditory stimuli
294
Describe the vestibulospinal tract's function.
Centre of gravity/posture
295
What is the function of the raphespinal tract?
Pain modulation
296
Describe what happens in UMN disease.
Initial period of spinal shock -> flaccid paralysis and areflexia.
Followed by hyperreflexia (loss of descending inhibition.
E.g.: Babinski's sign = dorsiflexion of big toe and fanning of others in response to stimulus along bottom of foot
297
What happens in LMN disease?
Flaccid paralysis, areflexia, and muscle wasting (atrophy)
298
What are the consequences of a C1-C5 lesion?
UMN signs (hyperreflexia) to all 4 limbs
299
What are the consequences of a C6-T2 lesion?
UMN signs (hyperreflexia) to legs; LMN signs (areflexia) to arms
300
What are the consequences of a T3-L3 lesion?
UMN signs (hyperreflexia) to legs; normal arms
301
What are the consequences of a L4-S2 lesion?
LMN signs (areflexia) to legs; normal arms
302
How can one test if spinal cord damage is unilateral or bilateral?
Test pain on both sides
303
Which functions do the sensory (afferent) cranial nerves play a role in?
```
General somatic (pain, temperature and touch).
General visceral/autonomic (parasympathetic.
Special sensory (taste, balance, and hearing).
```
304
What functions do the motor (efferent) cranial nerves contribute to?
```
General somatic (muscles of orbit and tongue).
General visceral/autonomic (parasympathetic).
Special visceral/brachial (brachial arch musculature of face, jaw, palate, larynx, pharynx)
```
305
Are any cranial nerves associated with the sympathetic nervous sytem?
No
306
Where are sensory brainstem nuclei located?
More laterally
307
Where are motor brainstem nuclei located?
More medial
308
Where are visceral brainstem nuclei located?
Near sulcus limitans
309
How are cranial nerves associated with brainstem nuclei?
Brainstem cranial nerve nuclei are associated with one or more cranial nerves.
If the nerve carries both sensory and motor information, it will have more than one nucleus.
All nuclei supply ipsilateral nerves EXCEPT nerve IV (trochlear)
310
Where is the olfactory nerve located?
Begins in olfactory epithelium inside nasal cavity. Project directly to olfactory bulb (an outgrowth of the telencephalon).
Does NOT project to thalamus.
311
What kind of cells make up the olfactory nerve?
Bipolar receptor cells with long unmyelinated axons.
| Group into small bundles called olfactory fila.
312
What is unique about olfactory receptors?
They are replaced throughout life
313
Where do olfactory tract fibres from olfactory bulb project to?
Primary olfactory cortex (piriform and periamygdaloid cortices) of temporal cortex.
Amygdala.
Olfactory tubercle.
314
How is the thalamus involved in olfactory processing?
Thalamus is involved in projections from piriform cortex to olfactory association cortex (orbitofrontal).
Combines with gustatory information.
315
What is anosmia caused by?
Conductive or sensorineural deficits in olfaction
316
What cells contribute to the optic nerve?
Photoreceptors (rods and cones)
Bipolar cells
Ganglion cells (axons form optic nerve)
317
Where does decussation of optic nerve occur?
Partial decussation of optic nerve occurs in optic chiasm where axons of nasal half cross the midline
318
Where does the optic tract travel to?
Lateral geniculate nucleus (LGN) of the thalamus
319
Where does the optic radiation project to?
The ipsilateral primary visual cortex (calcarine sulcus)
320
What happens when the optic nerve is damaged?
Damage affects ipsilateral eye
321
What is the consequence of optic chiasm damage?
Damage affects crossing fibres. Damage affects half of visual field (left field of left eye, right field of right eye)
322
What is the consequence of right optic tract damage?
Damage affects left visual field of both eyes
323
What are the two branches of the vestibulocochlear nerve? What functions do they contribute to?
Vestibular: proprioception and head position
Cochlear: hearing
324
Describe the utricle and saccule.
Static labyrinth.
| Linear acceleration.
325
Describe the semicircular canals. How many are there?
Kinetic labyrinth.
Angular acceleration.
3
326
Where does the vestibular nerve project to?
Vestibular nuclei and some direct projections to the cerebellum
327
Where does the vestibular nuclei have projections to?
Thalamus -> parietal cortex.
Vestibulospinal tracts (medial and lateral) to cerebellum.
Brainstem nuclei of cranial nerves III, IV, and VI (vestibulo-ocular reflex that matches head and eye movements)
328
How do sound waves produce activity in the ear?
Transduction of sound waves from outer ear -> middle ear -> movement of inner ear fluid.
Bending of hair cells in Organ of Corti (=cochlear nerve).
Inner hair cells: principle source of sound information.
Outer hair cells: control of sensitivity.
329
How is auditory information distributed within the CNS?
Bilaterally
330
What are the 5 motor cranial nerves?
Oculomotor (III), Trochlear (IV), Abducens (VI), Accessory (XI), and Hypoglossal (XII)
331
What are the 3 ocular motor cranial nerves?
Oculomotor (III), Trochlear (IV), and Abducens (VI)
332
Generally, which muscles do the ocular motor nerves innervate?
The 4 recti and 2 oblique muscles controlling eye movements.
Levator of upper eyelid.
Sphincter of the pupil and the ciliary muscle.
333
Where is the oculomotor nucleus located?
The rostral midbrain
334
Which muscles does the oculomotor nucleus innervate?
Ipsilateral: inferior rectus, inferior oblique, medial rectus
Contralateral: superior rectus
335
Where is the Edinger-Westphal nucleus? What does it innervate?
Rostral midbrain.
| These parasympathetic fibres innervate the ciliary and sphincter pupillae muscles
336
Where is the trochlear nucleus located? Which muscle does it supply?
Supplies the contralateral superior oblique
337
Where does the trochlear nerve exit?
Via the dorsal surface of the brainstem
338
Where is the abducens nucleus located?
Caudal pons
339
What muscle does the abducens nucleus innervate?
The lateral rectus
340
What action does the abducens nerve contribute to?
Abduction of the eye
341
Where is the accessory nucleus located?
Upper portion of cervical spinal cord
342
What does the spinal accessory nerve innervate?
Ipsilateral sternocleidomastoid (SCM) and trapezius
343
What actions does the spinal accessory nerve contribute to?
Shrugging shoulder and turning head to contralateral side
344
Where is the hypoglossal nucleus?
Along midline of medulla
345
Which muscles does the hypoglossal nerve innervate?
Extrinsic and intrinsic muscle of tongue
346
How do the corticobulbar fibres from primary motor cortex contribute to hypoglossal nerve action?
Fine movements like articulation
347
What actions of the hypoglossal nerve does the reticular formation contribute to?
Eating and swallowing
348
What is the result of supranuclear hypoglossal nerve damage?
Transient weakness of contralateral muscle.
| Tongue deviates away from side of damage (crossed projection)
349
What is the result of damage directly to the hypoglossal nerve or nucleus?
Weakness and atrophy of the ipsilateral muscle.
| Tongue deviates toward side of damage.
350
What are the 4 mixed cranial nerves?
Trigeminal (V)
Facial (VII)
Glossopharyngeal (IX)
Vagus (X)
351
How many branches and zones are there for the trigeminal nerve?
3 and 3: ophthalmic, maxillary, and mandibular
352
What parts does the sensory territory of the trigeminal nerve include?
The face, mucous membranes, teeth, dura mater, and intracranial blood vessels
353
How many motor/sensory nuclei does the trigeminal nerve have?
1 motor nucleus and 3 sensory nuclei
354
Which branch of the trigeminal nerve contains motor innervation?
The mandibular branch
355
Which muscles are innervated by the trigeminal nerve?
Muscles of mastication, tensor tympani, tensor palati, mylohyoid and diagastric muscle
356
What are the three sensory nuclei of the trigeminal nerve?
Mesencephalic, pontine (principle) and spinal trigeminal
357
Describe the mesencephalic nucleus.
Sensory nucleus of trigeminal nerve.
Only CNS nucleus to contain unipolar sensory neurons.
Peripheral process receives proprioceptive fibres from muscles of mastication.
Central process to supratrigeminal nucleus is associated with motor control (jaw)
358
Describe the pontine (principle) nucleus.
Sensory nucleus of trigeminal nerve.
| Discriminative tactile and proprioceptive information from face and oronasal cavity
359
Describe the spinal trigeminal nucleus as it is associated with the trigeminal nerve.
Sensory afferents from mouth.
| Nociceptive and thermal information from all 3 branches - face
360
What are the nuclei associated with CN VII?
Facial motor nucleus, superior salivatory nucleus, and solitary nucleus
361
Describe the facial motor nucleus.
Motor innervation to muscles involved in facial expressions and the stapedius (middle ear).
Nerve loops around abducens nucleus before leaving brainstem
362
Describe the superior salivatory nucleus.
Associated with the facial nerve.
| Parasympathetic outflow to secretory glands in eyes, nose, and mouth
363
Describe the solitary nucleus as associated with the facial nerve.
Associated with the facial nerve.
| Sensory input from anterior 2/3 of tongue and palate (gustatory)
364
What supranuclear innervations is there associated with the facial nerve?
All cell bodies receive corticobulbar innervation from contralateral motor cortex.
Muscles of upper face also receive ipsilateral innervation (for paired activities like wrinkling forehead)
365
What is the result of supranuclear facial nerve lesions?
Contralateral motor weakness of lower face
366
What is the result of nuclear facial nerve lesions?
Complete facial (and abducens) paralysis on side of lesion
367
What is the result of lesions directly to the facial nerve?
Complete facial paralysis on side of lesion.
| Unable to raise eyebrow, close the eye or retract lip
368
What are the four main functions of the glossopharyngeal nerve?
1. Primarily a sensory nerve carrying information from the viscera (ex. carotid sinus and carotid body)
2. Somatic sensory innervation (ex. pharyngeal muscles, outer ear, and posterior 1/3 of tongue)
3. Parasympathetic innervation (ex. parotid gland)
4. Motor innervation (ex. stylopharyngeus - swallowing and speaking)
369
What are the 4 glossopharyngeal nuclei?
Solitary nucleus, spinal trigeminal nucleus, inferior salivary nucleus, and nucleus ambiguus
370
What input does the solitary nucleus receive from the glossopharyngeal nerve?
Visceral sensory input from taste buds (posterior 1/3 of tongue), carotid body, carotid sinus and mucous membranes
371
What input does the spinal trigeminal nucleus receive from the glossopharyngeal nerve?
Pain from pharynx and posterior 1/3 of tongue.
| Somatic sensory input from outer ear
372
What is the function of the inferior salivary nucleus in relation to the glossopharyngeal nerve?
Parasympathetic innervation of the parotid gland (salivary gland)
373
What is the function of the nucleus ambiguus in relation to the glossopharyngeal nerve?
Branchial/special visceral efferent innervation of stylopharyngeus
374
What is the most widely distributed cranial nerve?
CN X (vagus nerve)
375
What are the functions of the vagus nerve?
Primary parasympathetic nerve to thoracic and abdominal viscera.
Sensory afferents and motor efferents to and from thoracic and abdominal viscera (visceral reflexes)
376
What are the vagus nerve nuclei?
Dorsal motor nucleus
Nucleus ambiguus
Solitary nucleus
Spinal trigeminal nucleus
377
What is the function of the dorsal motor nucleus in relation to the vagus nerve?
Preganglionic parasympathetic neurons that innervate viscera
378
What is the function of the nucleus ambiguus in relation to the vagus nerve?
Preganglionic parasympathetic innervation of heart and other thoracic organs.
Branchial motor innervation of larynx and pharynx (gag reflex)
379
What information does the solitary nucleus receive from the vagus nerve?
Special sensory innervation from taste buds of epiglottis and esophagus.
Visceral sensory information from thoracic and abdominal viscera, larynx, and pharynx.
380
Where does the spinal trigeminal nucleus receive information from in relation to the vagus nerve?
Larynx, esophagus, and pharynx
381
Which cranial nerves contribute to taste?
VII (facial), IX (glossopharyngeal) and X (vagus)
382
Where does the optic nerve go to in the thalamus?
The lateral geniculate nucleus (LGN)
383
Where does the vestibulocochlear nerve go to in the thalamus?
The medial geniculate nucleus (MGN)
384
Where does the olfactory nerve go to in the thalamus?
The dorsomedial nucleus and then to VPM to mix with taste input
385
Which cranial nerves go to the VPM?
Trigeminal, glossopharyngeal, and vagus (and olfactory eventually)
386
In general, which nuclei of the thalamus are associated with sensation from the body and face, respectively?
```
Body = VPL
Face = VPM
```
