The Central Nervous System Flashcards

1
Q

What stains are used for nerve tissue?

A

H&E
Nissl Stain
Osmium
Luxol Fast Blue
Silver Staining
Golgi Stain

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2
Q

Basic Neuron Structures

A

multipolar, bipolar, pseudounipolar

dendrites

cell body

axon

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3
Q

Neuron Configurations

A
  • Motor
    • multipolar
  • Sensory
    • Bipolar
    • pseudounipolar
  • Integrative
    • pyramidal
    • interneurons
    • Purkinje cell
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4
Q

Neuron Cell Body (Perikaryon)

A

“trophic center” - supports the process

contains nucleus with well developed nucleolus

nucleus is generally euchromatic → DNA is not compacted due to high transcriptional activity

Highly developed RER → nissl bodies

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5
Q

Axon

A

Constant diameter

generally do not branch

May be very long

Bidirectional transport

Specific motor proteins → Kinesin (anterograde → body to axon), Dynein (retrograde, axon to body)

Axon hillock → part of signal generation, stains more lightly b/c clear of organelles

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6
Q

Basic Neuron Histology

A
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7
Q

Dendrites

A

Small, branching processes important for neural plasticity → learning, adaptation, memory

contains actin filaments

receive and process signals

multiple synapses

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8
Q

Dendrite Histology

A
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9
Q

Synapses

A

(example of chemical synapse) Neurotransmitter release promotes ion uptake in postsynaptic membrane

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10
Q

Neurotransmitter

A

ACh and NE discovered first

can be excitatory or inhibitory

usually amines, amino acids, or small peptides

degraded in synaptic cleft, or taken up by exocytosis (prevent prolonged stimulation)

may act as paracrine hormones outside the. nervous system

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11
Q

Nervous System Organization

A
  • Functional
    • sensory
    • motor
  • Anatomical
    • central
    • peripheral
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12
Q

Nervous System: Functional Division: Sensory Nervous System

A
  • Some CNS and PNS components → includes all axons that transmit impulses from a peripheral structure to the CNS
  • Somatic sensory → transmits input from skin, fascia, joints, and skeletal muscle
  • Visceral sensory → transmit input from stomach and intestines (viscera)
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13
Q

Nervous System: Functional Division: Motor Nervous System

A
  • Some CNS and PNS components → includes all axons that transmit from the CNS to a muscle or gland
  • Somatic motor (somatic nervous system) → voluntary control of muscles (skeletal)
  • Autonomic motor (autonomic nervous system) → involuntary control of smooth muscle, cardiac muscle, and glands
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14
Q

Nervous System: Anatomical Division: Central Nervous System

A

Brain

Spinal Cord

Overall “command center”, processing and integrating information

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15
Q

Nervous System: Anatomical Division: Peripheral Nervous System

A

Ganglion (ganglia)

Peripheral nerves (axons of nerves)

Receives and projects information to and from the CNS; mediates some reflexes

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16
Q

Where is grey matter found in the brain?

A

cortex

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17
Q

Where is white matter found in the brain?

A

Medulla → nerve fibers and glial cells

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18
Q

Where is grey matter found in the spinal cord?

A

Medulla

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19
Q

Where is white matter found in the spinal cord?

A

Cortex

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20
Q

Where is the dorsal horn of the spinal cord?

A

Back (top)

gray matter

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21
Q

Where is the ventral horn found in the spinal cord?

A

Front (bottom)

gray matter

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22
Q

What are the three CT layers in the CNS?

A

Dura mater

arachnoid → subarachnoid space

pia mater (looser CT)

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23
Q

Tract

A

bundle of nerve fibers

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24
Q

Nuclei

A

prominate in spinal cord

aggregates of cell bodies

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25
Q

Glial Cells

A

Supporting Cells

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26
Q

Oligodendrocytes

A

cells that make myelin sheath

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27
Q

Types of Supporting Cells

A

Astrocytes

Microglia

Satellite Cells

Myelin Sheath → Oligodendrocytes,, Schwann Cells

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28
Q

Astrocytes

A

important for support of processes

form part of the blood brain barrier

express glial fibrillary acidic protein (GFAP)

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29
Q

The Blood-Brain Barrier

A

lipid soluble things can cross

bind to basement membrane of cells and form walls of capillaries

regulate tight junctions

30
Q

Microglia

A

Clean up

resident macrophages of the CNS

remove dead or dying neurons

31
Q

Oligodendrocytes

A

wrap processes around fibers to produce myelin sheath

insulates process to speed signal transduction

32
Q

Cerebral Hemisphere

A
  • Contralater control
    • right (hemisphere) controls things on left (Body)
    • left (hemisphere) controls things on right (body)
  • connected by neuron processes covered in fatty myelin sheath
  • white matter
    • cerebral white matter (associated with cortex)
    • corpus callosum (connects hemispheres)
    • internal capsule (connect cortex with brain stem)
33
Q

Fluid in the Brain

A

contained in spaces called ventricles

four cerebroventricles (associated with cerebrum)

chorid plexus makes cerebral spinal fluid

34
Q

Ventricles

A

First and Second ventricles are separated by the septum pellucidum

fourth is continuous with the central canal of the spinal cord

Lined with simple cuboidal epithelium (ependymal cells)

CSF enters venous blood through superior sagittal sinus

35
Q

How does cerebrospinal fluid (CSF) move around?

A

CSF drains into the dural venous sinuses → as blood drains from superior cerebral veins to area known as confluence of the sinuses

as blood flows, CSF flows into it

superior sagittal sinus

36
Q

Cerebrospinal Fluid (CSF)

A
  • Protects the brain (cushioning)
    • easy movement between spaces distributes fluid to avoid pressure changes
    • blockage increases pressure (damages neurons)
  • Removal of metabolic waste
    • drains from around CNS tissue into blood
  • Produced in choroid Plexus
    • choroid fissure in lateral ventricle
    • roof of 3rd and 4th ventricles
    • ependymal cells specialized for secretion
    • meningeal blood vessels (fluid production)
37
Q

Choroid plexus

A

simple cuboidal epithelium

loose lateral borders for fluid movement

38
Q

Choroid plexus histology

A
39
Q

Cerebrum

A
  • majority of brain in mammals
  • Highly convoluted surface
    • ridges - gyri/gyrus
    • grooves - sulci/sulcus
    • increase surface area which increases amount of cortex
    • relatively flat in chicken
  • Each hemisphere has 5 lobes
40
Q

What are the 5 lobes of the cerebrum?

A

Frontal (most rostral)

Parietal (separated from frontal by central sulcus)

Temporal (below parietal)

Occipital (at the back)

Insula (under frontal, parietal, temporal)

41
Q

Cerebral cortex (neocortex)

A

3 functional components: Motor, Sensory Association

42
Q

What is association?

A

receive sensory input and process

develop response

predict consequences

all 4 lobes

not well developed in cats and dogs, but present

43
Q

Association in the Lobes

A
  • Cognitive
    • Parietal
    • Occipital
  • General Alertness, Intelligence, and Temperament
    • Frontal Lobe
  • Learning and Memory
    • Temporal
44
Q

Motor in the Lobes

A

Humans - anterior to central sulcus

Other mammals - rostral to central sulcus

Pyramidal system - corticospinal fibers that travel through base of medulla oblongata → structures in base are cells medullary pyramids → travel to somatic motor neurons in the spinal cord

45
Q

Sensory in the Lobes

A

throughout the cortex

46
Q

What are the 6 layers of the Cerebrum in the cortex?

A
  1. molecular layer → no neurons, stain more lightly, next to pia mater
  2. external granular layer → no pyramidal cells
  3. External pyramidal cell layer → contains pyramidal cells
  4. internal granular layer → no pyramidal cells
  5. ganglionic layer (internal pyramidal layer) → contains pyramidal cells
  6. multiform (polymorphic) cell layer →. no pyramidal cells, close to white matter (closest to medulla), widely varied appearance
47
Q

Cerebrum Histology

A
48
Q

Pyramidal Cell Histology

A
49
Q

Diencephalon

A
  • Thalamus
    • major relay station for sensory information
  • Hypothalamus
    • endocrine organ that controls homeostasis and reproduction
  • Epithalamus
    • Endocrine organ that senses light
    • controls sleep/wake cycles through melatonin
    • seasonal breeding (estrus in sheep)
50
Q

Cerebellum

A
  • Second largest region (10% of mass)
    • contains half of all neurons
    • small convolutions call folia
  • purkinje cells
  • controls movement through connections to the brainstem and the cerebrum
  • coordination of muscle groups
  • control of stance and gait
  • regulation of muscle tone
51
Q

Purkinje Cells

A

Large with extensive dendritic tree

receive input from up to 200,000 neurons

includes proprioceptive, visual, tactile, balance, and auditory sensory information

52
Q

What happens if there is damage to the cerebellum?

A

interferes with performance of motor tasks

does not produce paralysis

53
Q

What are the 3 layers of the cerebellum in cortex?

A
  1. Molecular layer
  2. Purkinje Cel layer
  3. granule layer
  4. white matter (medulla)
54
Q

Cerebellum Histology

A
55
Q

Stellate vs. Basket Cell Histology

A
56
Q

Medulla Histology

A
57
Q

Medulla Oblongata

A
  • Continuous with spinal cord
  • Three major groups of nuclei
    • part of reticular formation (autonomic)
      • cardiovascular center
      • respiratory center
    • cranial nerves
    • relay stations from sensory and motor pathways
58
Q

Spinal Cord Anatomy

A
  • Continuation of Medulla Oblongata
  • In adult mammals, extends to lumbar vertebrae (½)
  • End is tapered section (conus medullaris)
    • amount of gray matter is highest at this point
    • decreases ascending to medulla oblongata
  • arachnoids and pia mater extend to sacrum to anchor the spinal cord
    • area is known as filum terminale
  • surrounded by bone meninges, and CSF
    • between meninges and bone is epidural space filled with loose CT, fat, and blood vessels
59
Q

Distribution of white/gray matter through spinal cord?

A

More white matter towards top

more gray matter towards bottom

60
Q

Spinal Cord Histology

A
61
Q

Central Canal Histology

A

contains CSF

lined with simple cuboidal epithelium (ependymal cells)

62
Q

Ventral horns of the spinal cord histology

A

Motor Neurons

63
Q

Dorsal Horns of the Spinal Cord

A

Sensory Neurons

64
Q

Meninges

A

Dura Mater

Arachnoid Mater

Pia Mater

65
Q

Meninges: Dura Mater

A

“tough mother”

tough fibrous layer

dense CT

outer layer connects to skull

66
Q

Meninges: Arachnoid Mater

A

loose covering over subarachnoid space

villi project through dura to sinus

CSF from 4th vesicle is found in subarachnoid space

large blood vessels in space (send capillaries and blood vessels through brain)

67
Q

Meninges: Pia Mater

A

Thin covering

adheres to CNS surface

small blood vessels that traverse into brain

68
Q

Dura Mater Histology

A
69
Q

Arachnoid Histology

A
70
Q

Pia Mater Histology

A