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Human Neuroanatomy > Exam 1 > Flashcards

Exam 1 Flashcards

1
Q

Overview of the Nervous System

A
  • Sensory receptors (the afferent system) and motor neurons/effectors are part of the PNS
  • Sensory info feeds into the CNS, where info is processed and sent to the effectors
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2
Q

Cells of the Nervous system

A

-Neurons- main cell responsible for integration and relay of messages -Glia- support neurons

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3
Q

Neurons

A

-Cell body and dendrites receive input -Axon hillock= summation of APs, integrative -Axon= conductive -Terminal branches= output -Metabolically compartmentalized- proteins made in cell body and dendrites only *Specialized cells that conduct APs over long distances (quickly)

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4
Q

How do neurons vary?

A

-Number of dendrites -Branching pattern of dendrites -One axon, but vary in # of collaterals

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5
Q

What are the two types of neurons?

A

-Projection neurons (sensory, motor, tract) -10% pop -Take info from one place to another (large distances) -Largest and best studied -Local Interneurons -90% -Unmyelinated -Modify info within local/small area -Small, difficult to study

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6
Q

Pseudounipolar cells

A

-One cell body, axon that starts as one and then branches into 2 collaterals -Ex: sensory neurons

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7
Q

Multipolar cells

A

-multiple dendrites and an axon -Ex: motor neuron– synapses to muscle

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8
Q

Local Interneuron

A

-no myelin -Multipolar

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9
Q

Nissl Stain

A

-Shows ribosomes bound to ER and nucleolus (site of RNA synthesis 4 ribosomes -Doesn’t stain axon -Stains proximal dendrites and cell body

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10
Q

Neuronal Cytoskeleton

A

-Microtubule- Largest, hollow tube, support axons, laid end to end -Neurofilament- stable, middle size -Microfilament- actin, found in parts of neurons that rapidly change (dendrites)

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11
Q

Axoplasmic Transportation

A

-How materials are moved within the cell -Use molecular motors and microtubules -Various rates of transportation -Anterograde- cell body to synapse -Retrograde- synapse to cell body

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12
Q

Features of the synapse

A

-Synaptic vesicles/secretory granules present at presynapse–> Hold NTMs -Postsynaptic density- proteins connecting the two synapses -Glia surround the synapse -Mitochondria at synaptic button produce ATP

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13
Q

Dendritic Spines

A

-Dendrites have numerous spines to maximize surface area to receive synapses -Neurons receive thousands of synapses which summate to create an AP

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14
Q

Glial Cells

A

CNS- -Ependymal cells -Microglia -Astrocytes -Oligodendrocytes PNS -Schwann cells -Satellite cells

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15
Q

Ependymal cells

A

-Line the ventricular system -Fluid-filled part of CNS -Cilia face inward to keep CSF moving

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16
Q

Astrocytes

A

-Most numerous -Surround neurons -Protoplasmic in gray matter -Fibrillar in white matter -Control extracellular environment (K+) -Take up NTMs -Break down glucose and pass it down to neurons

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17
Q

Oligodendrocytes

A

-Myelinate in CNS only, more than one axon -Each axon requires more than one oligodendrocyte

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18
Q

Microglia

A

-Derived from immune system, not nervous system -Phagocytes–> clean up cells -Respond to Injury -Found in resting state

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19
Q

PNS Glia

A

-Schwann cells myelinate only 1 axon in PNS —-Need many schwann cells to myelinated the same axon -Satellite cells- Support cells around neurons in ganglia

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20
Q

Grey vs White Matter

A

-G: Little myelin, mostly cell bodies and dendrites -W: a lot of myelin and oligodendrocytes

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21
Q

Early Nervous System Development

A

-Develops from ectoderm (outermost germ layer) -Begins to form at day 19- ectoderm worlds due to thickening of the neural plate -Neural groove–> neural tube–> CNS cells -Neural folds–> neural crest cells–> PNS

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22
Q

Neural Crest Cells

A

-Migrate to diff places and make ganglia -Become: —Sensory ganglia (dorsal root ganglia) —Autonomic ganglia (sympathetic, para-) —Enteric ganglia of the digestive system —Arachnoid and Pia covering (CNS) —Schwann cells —Adrenal medulla

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23
Q

Ganglia

A

-A collection of nerve cell bodies in the PNS -Formed from neural crest cells

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24
Q

Neural Tube

A

-Cells become CNS structures —Cerebrum- cerebral cortex and deep nuclei —Diencephalon, Midbrain, Pons, Cerebellum, Medulla —Spinal cord —Glial Cells of CNS

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25
Q

Neural Tube at week 4

A

-3 primary brain vesicles form –Forebrain/Prosencephalon (rostral most) –Midbrain/Mesencephalon –Hindbrain/Rhombencephalon (caudal most)

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26
Q

Neural Tube at week 5

A
  • Forebrain splits to Telencephalon and Diencephalon
  • Midbrain/Mesencephalon

-Hindbrain splits to Metencephalon and myelencephalon

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27
Q

Telencephalon

A

-Outgrows all other parts of the brain–> becomes cerebrum —Expands and fold to increase surface area

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28
Q

Sulci and Fissures

A

-Small grooves/valleys= sulci -Larger, deeper grooves= fissures

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29
Q

Major Lobes in the Adult Brain

A

-Frontal lobe -Parietal lobe -Temporal lobe -Occipital lobe —-Central sulcus separates frontal and parietal —-Lateral fissure separates temporal from frontal and parietal

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30
Q

Major Divisions of the Adult Brain

A

-Cerebrum -Brainstem -Cerebellum -Spinal cord

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31
Q

Ventricular System of the Adult Brain

A

-Fluid filled space within vesicles -Choroid plexus-> produces CSF -Inside= lumen

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32
Q

Neural Tube Defects

A

-Occur when neural tube fails to close in development -Spina Bifida–> failure to fuse at caudal end —Meningocele–CNS coverings exposed to outside of body —Meningomyelocele– Menigies and neural components exposed to outside of body -Anencephaly-Failure of rostral neural tube to develop–> no brain formation **Caused by folic acid deficiency, high glucose levels, retinoid acid

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33
Q

Neural tube breakdown

A

-Prosencephalon–> Telencephalon + Diencephalon

—Tel–> Cerebrum, cerebral hemispheres (cortex, white matter, basal nuclei), lateral ventricles

—Diencephalon–> Thalamus, hypothalamus, epithalamus, 3rd Ventricle

  • Mesencephalon- Brain stem, midbrain, cerebral aqueduct
  • Rhombencephalon–> Metencephalon + Myelenchepalon

—Metencephalon- brainstem, pons, cerebellum, part of 4th V

—Myelencephalon- Brainstem, medulla oblongata, 4th V -Spinal cord + central canal

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34
Q

Cerebrospinal Fluid

A

-Fluid w/in neural tube -Produced by choroid plexus -Clear fluid; similar to interstitial fluid, but diff from plasma -Potassium, calcium, bicarbonate, and glucose levels tightly regulated–Brain not subject to variations seen in blood -Volume- 150ml; Daily Production= 500ml -Circulates in spaces within brain (ventricular system) and through subarachnoid space around brain

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35
Q

Choroid Plexus

A

-Specialized ependymal cells that extract fluid and solutes from plasma and filter it -Located in the Lateral Ventricles

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36
Q

Ventricular System Flow

A

Lateral Ventricles–> Foramen of Monro–> 3rd V–> cerebral aqueduct–> 4th ventricle–> foramen of Magendie and Luschka (L and R)–> Superior Sagittal Sinus–> Arachnoid granulations

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37
Q

Location of Ventricles

A

-Lateral Vs-> under cerebral cortex -3rd-> midline btwn L and R thalamus -Cerebral aqueduct-> midline of midbrain -4th-> btwn pons/upper medulla, cerebellum

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38
Q

Problems in CSF circulation

A

-Blockage of circulation -Damage of arachnoid granulations -Overproduction– rare *Hydrocephalus–Not as dangerous in children cuz bones haven’t fused *Chiari malformation–> CSF directed down central canal to spinal cord, compressing spinal cord tissue

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39
Q

Spinal Taps

A

-How CSF samples are obtained -Needle inserted through skin btwn L4 and L5 -Test 4 abnormal: pressure, protein, glucose, blood cells, immunoglobulin

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40
Q

Divisions of the cerebrum

A

-Cortex: Outermost grey matter; perception, thought, conciousness -Limbic system- white matter structures encircling ventricular system; learning, memory, emotion -Basal ganglia- deep grey matter; motor control

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41
Q

Association Fibers

A

-Connect cortical areas on the same side of the brain -White fiber bundle

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42
Q

Commissural Fibers

A

-Connect cortical areas on opposite sides of brain -White fiber bundle -Ex: corpus callous

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43
Q

Projection Fibers

A

-Connect cortex w subcortical structures and other brain areas -Ex: Internal capsule and corona radiata

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44
Q

Internal Capsule and Corona Radiata

A

-Long projection fibers btwn the cortex and inferior structures that make up an array of vertically directed axons– corona radiata -Internal capsule- fibers from the corona radiata funnel into this compact fiber bundle lateral to the thalamus and caudate nucleus

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45
Q

Hippocampus

A

-Temporal Lobe Structure -Related to inferior horn of lateral v’s -Involved in learning, memory, spatial localization

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46
Q

Amygdala

A

-Temporal lobe structure -Related to inferior horn of lateral v’s -Receives info from all sensory systems -Mediates intense emotions such as anger and fear

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47
Q

Basal Ganglia

A

-A collection of nuclei -Regulates starting, stopping, and amplitude of activities -Parts- Caudate nucleus, putamen, globes pallidus -Caudate associated w lateral wall of lateral ventricle

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48
Q

Basal Forebrain area

A

-Lies anterior and lateral to the hypothalamus on each side -Near front end of corpus callous

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49
Q

Thalamus

A

-Gateway to the cortex -Occupies a central position in the brain (btwn brainstem and cerebrum; R and L) *R and L sometimes (NOT ALWAYS) connected by interthalamic adhesion -On either side of 3rd V

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50
Q

Thalamic divisions

A

-Based off of fxn 1. Anterior nuclear group 2. Pulvinar 3. Medial geniculate nucleus 4. Lateral geniculate nucleus *Each group projects to a diff region of cortex for diff sensations (except smell)

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51
Q

Hypothalamus

A

-Central to the limbic system -Homeostasis (body temp, endocrine, behavioral reg) -Group of nuclei -Boundaries: optic chasm, anterior commissure, maxillary body, lamina terminals

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52
Q

Epithalamus

A

-Contains pineal gland (melatonin production, regulates circadian rhythms) -Habenula- pain and reward pathways -Posterior commissure (connect L and R sides of the midbrain)

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53
Q

Subthalamus

A

-Nucleus -Part of basal ganglia circuitry; internal structure

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54
Q

Laminar organization of the cortex

A

-Sheet-like, horizontal organization of the cortex -Difference in thickness of the layers= basis for brodmann areas

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55
Q

Development of the Cerebral Cortex

A

-Cells are born in the ventricular zone -cells differentiate into neurons and “climb” radial glia to cerebral surface -Newer cells= top layer, older on bottom -Adult cerebral cortex= 6 layers —-Layer 1= Pia matter

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56
Q

Vertical Organization of the Cerebral cortex

A

-The cortical column- built around pyramidal cells —Columns of cells oriented perpendicular to the surface of the cortex that are individual functional units *Columns encompassing all 6 layers will fire when receptive field is reached

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57
Q

Layer 5 of the cortex

A

-Location of pyramidal cells -Output to subcortical areas -Contains Betz cells -Projection fibers

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58
Q

Pyramidal cells

A

-Dictates whether that part of the cortex will send an output -Define boundaries of one cortical column -Long dendrites that extend to layer 1–> apical dendrites -Basal dendrites extend to bottom of layer 5 -Recurrent collaterals- project into layer 6 -Axon projects into subcortical areas

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59
Q

Layer 1 of the cortex

A

-Plexiform/molecular layer -Fibers parallel to the surface

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60
Q

Layers 2/3 of the cortex

A

-Small and medium pyramidal layers -Intracortical connections -Short and long association fibers -Commissural fibers —Stellate and pyramidal neurons with intracortical connections

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61
Q

Layer 4 of the cortex

A

-Inner granular layer -Stellate neurons receive INPUT from thalamic nuclei

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62
Q

Layer 6 of the cortex

A

-Fusiform/multiform layer -Cortical output to specific thalamic nuclei —-inputs and outputs to thalamus

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63
Q

Motor areas and sensory areas in regard to cortex layers

A
  • Motor areas have large layer 5, small layer 4 -Sensory areas have large layer 4, small layer 5
  • Association ares= in between
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64
Q

Brodmann’s areas

A

-Defined specific cortical areas based on their histology and functional correlates

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65
Q

Functional areas of the cerebral cortex

A

-Primary areas–> devoted to only 1 function —-Primary visual, auditory, motor, and somatosensory cortices —-Described w maps -Associated areas–> make sense of info —Interpretive, integrative, complex processing

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66
Q

Lateralization of the cerebral cortex

A

-Processes info related to opposite side of body -L: analytical, precise, organized, literal -R: creative, imaginative, conceptual, intuitive -Dominance: often, one side more strongly controls an activity -Ex: language predominates left side

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67
Q

Occipital Lobe

A

-The visual cortex–Brod area 17 —-Map of contralateral retina–points in visual space -Visual association cortex- Brod area 18/19 —Interpretation

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68
Q

Dorsal and Ventral Pathways of Visual cortex

A

-Where= dorsal, what=ventral -Feeds info away from occipital lobe to other brain areas (memory areas) -Damage leads to visual deficits/ “cortical blindness”

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69
Q

The primary auditory cortex and association area

A

-Temporal lobe; temporal lobe gyrus inside lateral fissure -Brodmans area 41/42 -Map of tones; sounds mix in both hemispheres -Association area- interprets pattern of sound —-BA 22

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70
Q

Wernicke’s Area

A

-reading mentally, interpreting speech -Dominant side= left *Part auditory cortex, part association cortex -Damage–> sensory aphasia-> inability to understand speech; fluid nonsensical speech

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71
Q

Visual Association Cortex

A

-Temporal Lobe -ID of stimuli we recognize -Agnosias= difficulty recognizing stimuli, naming categories of things *Ex: prosopagnosia= inability to recognize faces *Dominant= left

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72
Q

Primary Somatosensory Cortex and Association area

A

-Parietal lobe -PSC- Lies on the post central gyrus, BA 3,1,2 —-Map of contralateral body —-Somatic sensation (touch, pain, temp) -AA- Superior parietal lobule (BA 5+7) —-Interprets sensations in space

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73
Q

Sensory Homunculus

A

-Neurons of the primary somatosensory cortex are topographically arranged and receive sensory signals from diff parts of the body -Greater area= greater sensory acuity

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74
Q

Subdivisions of the Frontal Lobe

A

-Motor region -Prefrontal region

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75
Q

Motor Region of the Frontal Lobe

A

-2 final areas: –1. Primary motor cortex= BA 4 ———precentral gyrus; map of skeletal muscles (primary motor strip) –2. Premotor cortex (rostral to primary motor) ——–Designs motor plan; activaion and synchronization of groups of muscles

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76
Q

Motor Homonculus

A

-Neurons of the primary motor cortex are topographically arranged and execute commands to skeletal muscles in diff parts of the body

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77
Q

Broca’s area

A

-Adjacent to speech muscle area of primary motor cortex on DOMINANT SIDE (left) -Damage gives “expressive aphasia” or “non-fluent aphasia”–> defective grammar/difficulty producing speech

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78
Q

Parts of the Prefrontal Cortex

A

-Complex behavioral areas 1. Dorsolateral PFC 2. Orbitofrontal cortex 3. Anterior cingulate

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79
Q

Dorsolateral PFC

A

-Working memory –Ex: remembering a phone # -Associative memory–> learn to associate an action w/ reward -Executive fxn

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80
Q

Orbitofrontal Cortex

A

-Involved in social and emotional decision making –Risk vs reward -Damage– loss of inhibition/ change in behavior *Last part of the brain to reach maturity

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81
Q

Anterior cingulate

A

-Involved in motivation -If damaged–> Akinetic mutism (not motivated to speak)

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82
Q

Tasks for executive system impairment

A
  • Alternating sequences task —-Patient asked to draw a circle, then a triangle —Inability to disengage from stimulus —Preservation
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83
Q

Frontal vs. Parietal Association Cortex

A

-Posterior parietal cortex orients attention toward extra personal world (things around u/ ur body) -Prefrontal association cortex orients attention toward internal mental processes

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84
Q

Insular Cortex

A

-Feelings and self-awareness -How feelings are colored onto the body

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85
Q

4 types of organization w/in the brain

A
  1. Laminar/Horizontal 2.Cortical column/ Vertical 3. Functional (BAs) 4. Topographical (homunculi)
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86
Q

Peripheral Nerves

A

-Connect CNS to periphery

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87
Q

Spinal Nerves

A

-31 pairs of spinal nerves that connect peripheral structures to the spinal cord -Share similar organization; contain motor and sensory fibers -Cell bodies located in dorsal root ganglia -Mixed nerve–> sensory and motor mixed together

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88
Q

Cranial Nerves

A

-12 pairs that connect brain to periphery -Every cranial nerve is diff from the others -CN II is CNS tissue, formed from neural tube

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89
Q

Neuron Types in the PNS

A

-Sensory -Motor

90
Q

Sensory Neurons

A

-carry info from receptor into CNS -Axon= sensory axon or sensory fiber; pseudounipolar -Cell body located in PNS ; joins w others to form ganglion *No dendrites

91
Q

Types of Sensory Neurons

A

-Somatic sensory- Receive info from skin or skeletal muscle (axons= somatic sensory axons) -Visceral sensory-receive info from receptors in organs (axon visceral sensory axons)

92
Q

Motor Neurons

A

-carry info out of CNS, into PNS -Axon= motor axon or motor fiber; unipolar -Cell body located within gray matter of CNS -Many dendrites; synapse on target cells in periphery

93
Q

Types of Motor Neurons

A

-Somatic Motor- Carry info to skeletal muscle; release NTM onto it so muscle contracts -Autonomic motor/Visceral Motor- go to organs; chain of 2 neurons (1st= preganglionic, 2nd is postganglionic)

94
Q

Nerve types in the PNS

A

-Further classified according to which types axons are mixed within the nerve 1.Motor nerve 2. Cutaneous nerve 3. Splanchnic nerve

95
Q

Motor Nerve

A

-Nerve that enters muscle cells -Contains 2 axon types: —Somatic motor fibers (axon)= synapses on skeletal muscle cells —Somatic sensory fibers (axons)= collect info from sensory receptors in muscle and carry it back to the CNS

96
Q

Cutaneous Nerve

A

-Nerve that enters a patch of skin -2 axon types: —Somatic sensory fibers (axons)- collect info from sensory receptors in skin; carry back to CNS (touch info) —Autonomic motor fibers (axons)- synapse to smooth muscle or gland cells in skin

97
Q

Splanchnic Nerve

A

-Nerve that enters an organ -2 axon types: –Visceral sensory fibers (axons)- collect info from sensory receptors in organ and carry to CNS –> info helps CNS adjust conditions of organ –Autonomic motor fibers (axons)- Synapse on cardiac muscle cells, smooth muscle cells, or gland cells in organs to alter organ fan

98
Q

Innervate

A

-When an axon contacts a cell or structure in the body -4 motor axons–> synapses on skeletal muscles -4 sensory axons–> synapses

99
Q

Axons in the PNS

A

-Myelinated; produced by Schwann cells -Schwann cells also ensheath axon–> Hug axons w/o myelinating them

100
Q

Thickness of Myelin Sheath and Axon Diameter

A

-Proportional to each other -Increased myelin or axon diameter increases conduction speed -Diff fxnal classes of peripheral axons conduct APs at diff speeds -Ex: A and B fibers= myelinated, C is unmyelinated (pain, temp, mechanoreception)

101
Q

Structure of Peripheral Nerves

A

-Axons organized by specific connective tissue coverings —–Axons w or w/o myelin arranged into fascicles -Schwann cells -Blood vessels nourish cells *Axons could be sensory or motor, but look identical -Connective tissue layers –Around each axon= Endoneurium (deepest layer) –Around each fascicle– Perineurium –Around the entire nerve= Epineurium (tough outer coating)

102
Q

Fascicles

A

-Group of axons bundled together with collagen-rich connective tissue -Have a common fxn *Only in PNS

103
Q

Can one neuron be myelinated by oligodendrocytes and Schwann cells?

A

-Yes! -Part of axon may be in CNS–>myelinated by oligo -Part may be in PNS–> myelinated by Schwann

104
Q

Differentiation within the neural tube (Dorsal-Ventral)

A

-Cells divide into the ventricular zone and migrate from the ventricle within the wall -In SC–> dorsal alar plate (eventually dorsal root) and ventral basal plate develop (ventral root) -Sulcus limitans= the grove in the lateral wall of the neural tube delineating alar from basal plates

105
Q

Differentiation of the neural tube (Medial-Lateral)

A

-Hollow opening in center= ventricle -Ventricular layer= dividing cells -Mantle layer= neuroblasts —Cells migrate, differentiate -Marginal layer= axon growth

106
Q

Development of the Spinal Cord

A

-Central grey portion–> Dorsal and ventral horns -Central canal does not enlarge -White matter surrounds the grey

107
Q

Dorsal Root Entry Zone

A

-Medial DREZ= myelinated axons entering from dorsal root -Lateral DREZ= unmyelinated axons entering from the dorsal root

108
Q

Spinal Cord at Diff Levels

A

-The overall cross-sectional size of the SC decreases from cervical to sacral levels -Volume of white matter decreases from cervical to sacral levels **Shape of grey matter changes at each level —Greatest volumes of dorsal and ventral horn at limb attachment -Some areas have lateral horns

109
Q

Spinal Cord- White Matter

A

-Carry info up spinal cord (ascending tracts) OR -Down from brainstem or cerebrum–> descending tracts *No connective tissue separating tracts -Tracts are only sensory or motor, never both

110
Q

Spinal Cord-Grey Matter

A

-Organized into nuclear cell columns OR Rexed’s Laminae

111
Q

Rexed’s Laminae

A
  1. Marginal Zone 2-3- Substantia Gelatinosa 4- Nucleus Proprius 6-7-Column of Clark 9- Motor neurons *Different lamina are related to diff functional systems
112
Q

Dorsal and Ventral Ramus

A

-Mixed- sensory and motor -Names refer to location of body they go to —Dorsal branches to dorsal skin and muscle —Ventral branches to ventral skin and muscle

113
Q

Dorsal Roots and Rootlets

A

-Only sensory axons

114
Q

Ventral roots and rootlets

A

-Only motor axons

115
Q

Spinal Nerves are the first point where…

A

-First point where sensory and motor axons are bundled together

116
Q

Comparison- CNS vs PNS: Terms describing clusters of neuron cell bodies

A

-CNS: gray matter, nuclei, centers, horns -PNS: Ganglia *All supported by glia

117
Q

Comparison- CNS vs PNS: terms describing groups of axons

A

-CNS- white matter, tract, funiculi, fasiculi, fiber bundles (ex: corpus callosum) -PNS: Nerves, fascicle

118
Q

Meissner’s Corpuscles

A

-Just under skin surface -Sensitive to fine touch -Lead to stimulation of 1st order sensory neurons *Rapid adapting- fire quickly and stop firing quickly

119
Q

Pacinian Corpuscles

A

-Deep under surface of skin -Sensitive to pressure and vibration -Lead to stimulation of 1st order sensory neurons *Rapidly adapting- fire quickly and stop firing quickly

120
Q

Merkel Cells

A

-Located just under the surface -Sense of fine discriminative touch -Lead to stimulation of 1st order sensory neurons *Slow adapting

121
Q

Ruffini Endings

A

-Deep under skin -Provide touch directionality *Slow adapting

122
Q

Free Nerve Endings

A

-Stimulate 1st order sensory neurons -Sensations of pain and temp *not a receptor* -Channels in axon at peripheral terminus change conductance in response to heat or cold/ local chemicals *Localized in skin, connective tissues, and organs

123
Q

Sensory receptors of skeletal muscle

A

-1a fiber=muscle spindle —Detect stretch of mucle -1b fiber= tendon ending/ golgi tendon

124
Q

Hierarchy in somatosensory pathway

A

Stimulus–> receptor–> 1st order neuron in PNS (dorsal root gang)–> 2nd order neuron in CNS (SC or brainstem)–> 3rd order neuron in thalamus–> neuron in primary sensory cortex–> conscious perception of stimulus *reflexes occur at 2nd order neuron

125
Q

Divergence

A

-Ex; Somatosensory system; Muscle afferents -One input in CNS can be sent to many areas simultaneously -Info can be processed in multiple ways in multiple sensory pathways

126
Q

3 Major Spinal Somatosensory Pathways

A
  1. Dorsal Spinocerebellar Pathway 2. Dorsal Column/Medial Lemniscal Pathway 3. Anterolateral pathway (spinothalamic)
127
Q

Dorsal Spinocerebellar Pathway

A

-1a, 1b, Abeta afferents -Muscle length -Muscle contraction -Joint contraction *1st order neuron= Dorsal root gang cell *2nd= neuron in column of clark – dorsal spinal cerebellar tract in lateral funiculus (ipsilateral SC)–> *3rd: ipsilateral cerebellum

128
Q

Column of Clark

A

-Only present from C8 to L2

129
Q

Dorsal Column/ Medial Lemniscal Pathway

A

-1a, 1b, Abeta afferents -Fine touch, vibration, conscious proprioception -1st order- DRG sensory neuron *Dorsal column tract in SC* -2nd order- Gracile or cuneate nucleus (lower medulla) **CROSS THE MIDLINE TO OPPOSITE SIDE OF BRAINSTEM, medial lemniscus pathway in brainstem -3rd order- VPL nuc of thalamus *Sensory axons in this pathway travel in dorsal funicular of ipsilateral SC (don’t relay through dorsal horn nuc)

130
Q

Gracile Fasciculus and Cuneate Fasciculus

A

*Parts of the dorsal funiculus -Gracile= feet/lower body/ below T6 -Cuneate= arms/ upper body/above T6 T6= bottom of sternum

131
Q

VPL

A

-Relay nucleus of the Medial Lemniscus Pathway -Axons travel trough internal capsule and synapse in layer 4 of the primary somatosensory cortex

132
Q

Anterolateral System

A

-Adelta (sharp pain), C afferents (dull itching or burning) –Pain, temp, itch, crude touch 1. DRG sensory neuron (free nerve endings stimulated) 2. Marginal nucleus or nucleus proprius (dorsal horn of ipsilateral sc) **Cross midline, ascends to brain via anterolateral tract** 3. VPL nucleus of thalamus –> relays to somatosensory cortex

133
Q

Marginal Nucleus

A

-Alpha Delta fibers carrying sharp pain, some temp -Where dorsal root ganglion neurons synapase in the anterolateral pathway

134
Q

Reticular Formation

A

-Responsible for autonomic and limbic connections of pain —Arousal —Emotional component of pain

135
Q

Spinal Cord Sensory Pathways

A

-1st order neurons are DRG cells–> bring in info from mechanoreceptors and free nerve endings 2nd order neuron= CNS cells which relay to brain -If info is destined for cortex, 3rd order neuron= part of thalamus

136
Q

Spinal MOTOR pathways

A

-DONT USE TERMS 1ST ORDER, 2ND etc -Upper motor neurons and lower motor neurons -Axons form descending tracts traveling in white matter

137
Q

Lower Motor Neurons

A

-Cell bodies in ventral horn -Project to skeletal muscles

138
Q

Upper Motor Neurons

A

-Cell bodies and axons in CNS -Regulate LMNs

139
Q

Somatic motor neurons in the ventral horns

A

1.Alpha Motor Neurons 2.Gamma Motor Neurons -Project through motor nerves -Terminate on skeletal muscle at neuromuscular Jxn *Only source of skeletal muscle activity Axon damage= cells in motor unit cant contract Nerve damage= whole muscle cant contract

140
Q

Alpha Motor Neurons

A

-Large in diameter -Rapidly conducting cells -Cause skeletal muscle cells to contract

141
Q

Gamma Motor Neurons

A

-Smaller, slower conducting cells -Control tiny muscle cells within muscle spindle receptors -Modulate the sensitivity of MS receptors

142
Q

Motor Unit

A

-One alpha motor neuron and all the muscle cells it innervates –Small: innervates about 10 cells –Large: innervates 1000 cells= less fine control

143
Q

How Gamma and Alpha motor neurons work at a muscle spindle

A

-if only alpha motor neurons were activated, only extramural muscle would contract–> muscle spindle becomes slack and no APs fire–> cannot signal further length changes -When alpha and gamma coactivated–> extrafusal and intrafusal contract–> tension is maintained in muscle spindle and can signal changes in length

144
Q
A
145
Q
A

Choroid plexus

146
Q
A
147
Q
A
148
Q
A
149
Q
A
  • Red circle= subthalamus
  • Blue circle= epithalamus
150
Q
A

Blue- Dorsolateral PFC

Red-Orbitofrontal PFC

White- Anterior cingulate

151
Q
A
152
Q
A
153
Q
A
154
Q
A
  1. Spinocerebellar Pathway
  2. Dorsal Column/Medial Lemniscal Pathway
  3. Anterolateral Pathway
155
Q
A
156
Q
A
157
Q

The Meninges

A
  • Protective covering of the CNS
    1. Dura mater-tough outer membrane
    2. Arachnoid mater- Thin, transparent membrane covering superficial blood vessels in the cortex
    3. Pia Mater- layer adjacent to brain
  • Cannot be removed w/o tearing brain tissue
158
Q

Spaces within the Skull

A
  • Epidural space: between skull and dura
  • Occurs upon injury- not normally there
  • Subdural space: Btwn dura and arachnoid

–Not normally there

-Subarachnoid space- contains CSF

—Location of superior saggital sinus

159
Q

Where are blood vessels located within the brain?

A
  • W/in the dura (supply dura only)
  • Btwn arachnoid and pia

—Supply blood to brain

160
Q
A
  1. Yellow–> Cerebrum
  2. Green–> brainstem
  3. White–> Cerebellum
161
Q

What fissure separates the left and right hemispheres?

A

-Interhemispheric fissure

162
Q
A
  1. Red: Frontal lobe
  2. Blue dots= central sulcus
  3. Yellow: Parietal lobe
  4. White dots= Lateral fissure
  5. Black= temporal lobe
  6. Green= occipital lobe
163
Q

Where can the insular cortex be found?

A

-At lateral fissure, pull temporal lobe apart from frontal and parietal lobes

164
Q
  • Back?
  • Front/Stomach?
  • Coccyx?
  • Brain/head?
A
  • Back= dorsal/posterior
  • Front= ventral/anterior
  • Coccyx= caudal
  • Brain/head= rostral
165
Q
  1. Separating hemispheres?
  2. Separating dorsal and ventral planes
  3. Vertical separation
  4. Separating superior and inferior portions
A
  1. Sagittal (midsaggital if perfect split, parasaggital if unequal)
  2. Coronal/Frontal
  3. Transverse
  4. Horizontal
166
Q
A
  • Flax cerebri= btwn cerebral hemispheres
  • Tentorium cerebelli= btwn occipital lobe and cerebellum
167
Q
A
168
Q

What described the 90 degree angle that the brain and brainstem form?

A

-Mesencephalic Flexure

169
Q
A
  1. Red= lateral ventricles
  2. Clip= Septum pellucidum–>membrane separating left and right LVs
  3. Yellow- Foramen of monro
  4. Blue-> 3rd V
  5. White= cerebral aqueduct
  6. Black= 4th Ventricle
170
Q

What are the 3 drainage holes from 4th ventricle into subarachnoid space?

A
  1. Foramen of Magendie= midline
  2. Two foramen of Lushka- lateral
171
Q
A
  1. Superficial Gray matter
  2. White matter
  3. Deep greymatter
172
Q
A

Caudate, Putamen, and Globus Pallidus= Basal Ganglia *Grey matter

173
Q
A

Red cross= optic chiasm

Blue= Anterior perforated substance

—Ventral surface where BVs penetrated

174
Q
A

Blue circle- amygdala

Arrows= hippocampus

175
Q
A
  • Triangle= hypothalamus
  • Blue= Thalamus
  • Yellow= epithalamus
  • Green= subthalamus
176
Q
A

-interthalamic adhesion

*only some people have it

177
Q
A

White= pons

Yellow= floor of the hypothalamus

Red= optic chiasm

-Black hole below optic chiasm= pituitary stalk

178
Q
A

1.Parieto-Occipital fissure

179
Q
A
180
Q
A

Primary Motor Cortex/ Brodmann’s area 4/precentral gyrus

181
Q

Motor Homunculus

A
  • Tongue near insula
  • Toes/leg near interhemispheric fissure
182
Q
A

-Premotor cortex/BA 6/Part of superior and middle frontal gyri

183
Q
A
  • Broca’s area: BA 44 and 45
  • Motor speech
184
Q
A

-Prefrontal Cortex

185
Q
A
186
Q
A

-Primary somatosensory cortex/ BA 3,1,2/post-central gyrus

187
Q

Somatosensory Homunculus

A
  • Tongue, pharynx, intrabdominal–>insula area
  • Leg= intrahemispheric fissure
188
Q
A

Red=Somatosensory association cortex (BA 5and7)/ superior parietal lobule

-Blue= intraparietal fissure

189
Q
A

-Inferior parietal lobule

190
Q
A
191
Q
A
  • Primary visual (blue)- BA 17
  • Calcarine fissure (red)
  • Visual association cortex- White- BA 18 and 19

-

192
Q
A
193
Q
A
  • Primary Auditory Cortex (green)- BA 41 and 42
  • Auditory association cortex (yellow)- BA 22
194
Q
A

Red= Broca’s are- BA 45 and 44

Yellow=Wernicke’s area= BA 22

195
Q
A

-Parahippocampal gyrus

196
Q
A

Uncus

197
Q

Spinal Cord

A
  • Continuation of the brainstem
  • Bones of spine create a protective canal
198
Q
A
199
Q
A
  • Intervertebral disk-> cartilage btwn each pair of vertebral bodies
  • Vertebral canal= formed by alignment of vertebral foramina
  • Intervertebral foramen- formed on each side between every pair of vertebrae
200
Q

Organization of the spine

A
  • 7 cervical vertebrae
  • 12 thoracic vertebrae
  • 5 lumbar vertebrae
  • 1 sacrum (fusion of 5 sacral vertebrae)
  • 2-4 coccygeal vertebrae–> coccyx
  • Numbered

*Spines point posteriorly

*Bodies point anteriorly

-Spinal canal lies within the vertebral canal–> stops around L1/L2

201
Q

Meninges surrounding the spinal cord

A
  • Pia= adheres to SC
  • Arachnoid- external to pia, attached by fine fibers
  • Dura- surrounds arachnoid, extends out of the intervertebral foramina as dural sleeves
  • Epidural, subdural, and subarachnoid spaces similar to brain, but dura not attached to bone

*Fat gives padding btwn dural sac and bone

202
Q
A
  • Space= central canal
  • Grey matter is further divided into Rexed Laminae
203
Q
A
  • Rootlets merge into roots
  • Roots move laterally, run within dural sleeve
  • Spinal nerve and rami= mixed
  • Ventral ramus= supplies anterior muscles and skin

—Larger than dorsal

-Dorsal ramus= supplies posterior muscles and skin

204
Q
A
  1. White matter
  2. Grey matter
  3. Dorsal root
  4. Ventral root
  5. DRG
  6. Spinal nerve
  7. Anterior
  8. Posterior

Top arrow= dorsal ramus

Bottom arrow= ventral ramus

205
Q

Lumbar Cistern

A

-Pool of CSF that surrounds the rootlets of the cauda equina in the dural sac

206
Q

Why is a spinal tap performed at the L3/L4 or L4/L5 level?

A

-To reach the lumber cistern, needle isn’t likely to damage the cauda equina

207
Q

What structures are in the dural sac at the L3/L4/L5 level?

A
  • Cauda equina
  • Lumbar cistern
208
Q

Why are spinal taps not performed at the T12/L1 level?

S3/S4 level?

A

-Cannot be performed at T12/L1 cuz could damage the spinal cord

-S3/S4 would not work because dural sac ends b4 then

209
Q

What meningeal layers must the needle pass through to collect CSF?

A
  • Dura
  • Arachnoid

*Goes into subarachnoid space

210
Q
A

-Filum terminal= strand of pia mater; attached to bottom of dural sac

211
Q

Numbering of the spinal nerves

A

-Numbered according to the vertebrae where they exit

-Cervical spinal nerves exit above the same numbered vertebrae

—-Ex: C3 SN exits between C2 and C3

-Thoracic, Lumbar, and sacral SNs exit below same numbered vertebra

–Ex:T5 exits between T5 and T6

*C8= exiyd below C7 and above T1

**Spinal nerves= organized topographically

212
Q

Which levels of the spinal cord have the largest volume of grey matter? Why?

A

-Thoracic has the largest volume of grey matter because a lot of cell bodies are located there. Additionally, not as much white matter because not a lot of motor function occurs here.

213
Q

Which levels of the spinal cord have the largest amount of white mater? Why?

A

-Cervical and lumbar because they are important for sensory and motor functions within the arms and legs

*Overall, WM greatest at cervical and least at sacral

214
Q

Spinal Segments

A
  • Give rise to dorsal and ventral rootlets, and spinal nerves
  • For every spinal nerve, we can refer to its spinal segment
215
Q

Plexus

A

-A network of nerves undergoing the sorting process

–Nerves branching from the plexus redistribute to muscles and skin

  • Brachial plexus= Rostral end, formed from ventral rami C5-T1– Innervate muscles and skins in upper limbs
  • Lumbosacral plexus- Caudal end, formed from L1-S5 ventral rami- innervate muscles and skin of lower limbs and pelvis
216
Q

Organization of cell bodies in the ventral horn

A
  • Medial ventral horn= motor neurons for chest and back
  • Lateral VH= Motor neurons for arm and hands
217
Q

Is there a relationship btwn size of gray matter and the amount of info being processed?

A

-Increased grey= increased info processed

218
Q

Which levels of the SC process the most info? Why?

A

-L1-S5 and C5-T1 (brachial plexus and lumbosacral plexus) because they are processing touch and moving limbs

219
Q
A
220
Q

Which two named areas in the dorsal horn have the largest pop. of neurons? What are their Rexed Laminae?

A

-marginal zone (I) and nucleus proprious (IV)

221
Q

Which cell group in the ventral horn has the largest pop of neurons? Rexed Laminae of this group?

A

-Alpha motor neurons in the ventral horn (XI)

Human Neuroanatomy (5 decks)

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