Module 1/2 - Structure and development of the nervous system and cells of the nervous system

Question 1

Why do we have a nervous system?

Answer 1

To react to in response to stimuli around us

Question 2

Difference between invertebrate and vertebrate brains

Answer 2

Ventral nerve cord compared with a dorsal cord in vertebrates

Question 3

Divisions of the brain

Answer 3

Spinal cord - spinal cord
Hindbrain - Pons, Medulla
Midbrain - Tectum, Tegmentum
Forebrain - Diencephalon (Thalamus, Hypothalamus) and Telencephalon (Cortex, Olfactory bulb)

Question 4

Three layers of cells

Answer 4

Endoderm, mesoderm, ectoderm

Question 5

Endoderm

Answer 5

The lining of the organs, and tracts (innermost layer)

Question 6

Mesoderm

Answer 6

Forms bones and cartilage (the middle layer between the endoderm and ectoderm)

Question 7

Ectoderm

Answer 7

Outermost layer (skin, hair, nails) and the nervous system

Question 8

The neural tube: what is it formed from and what happens with the nervous systems?

Answer 8

Formed by the folding of the neural plate

CNS is formed from the walls of the tubes and PNS is formed from the neural crest

Question 9

Spina Bifida: what is it, what is the treatment, and what may influence its occurrence?

Answer 9

The failure of the posterior neural tube to close

Supplementing the diet with folic acid reduces the likelihood of it happening by 90%

Antiepilepsy and antibipolar drugs may interfere with embryo metabolism and influence Spina Bifida

Question 10

Ventricles: what are they in the brain and what do they do?

Answer 10

Four cavities filled with cerebrospinal fluid

They act as a cushion for the brain, remove waste and maintain chemical stability

Question 11

The spinal cord: what are the things near it and what do they do, what does the spinal cord do, what do the dorsal roots mostly contain, and what do the ventral roots mostly contain?

Answer 11

Protected by the spinal column and surrounded by meninges and cerebrospinal fluid

The spinal cord transmits messages from the brain to the periphery and acts as the primary channel for messages from the skin, joints, and muscles to the brain

Dorsal contains sensory and afferent neurons

Ventral contains motor and efferent neurons

Question 12

Parts of the spinal cord

Answer 12

Dorsal root ganglion, dorsal root, ventral root, grey matter (neuron cell bodies), white matter (myelinated axons), central canal, and anterior commissure

Question 13

Brainstem: what is it and what does it contain?

Answer 13

The oldest part of the brain which acts as a decision matrix and controls vital processes

Midbrain (controlling movement and sensory input (eyes, ears)), and some parts of the Hindbrain (Pons and Medulla)

Question 14

Pons: where is it located and what does it do?

Answer 14

Swells out from the ventral surface of the brain stem and is important in the relay between the cortex and cerebellum

Question 15

Medulla: where is it located and what does it do?

Answer 15

The bottom part of the brain, below the Pons and the cerebellum.

Important in blood pressure and ventilation control.

Question 16

Hydrocephalus: what is it and what does it do?

Answer 16

Brain stem damage, may cause damage to the Medulla and therefore respiratory arrest

Question 17

Cerebellum

Answer 17

A part of the brain you can live without. It affects motor functions and it has extensive connections to the cerebellum and spinal cord (at least as many as both hemispheres)

Affected by alcohol and Ataxias. Those suffering from Ataxias may be perceived as drunk because motor issues occur in either situation

Question 18

Cerebral cortex: what is it, what does it do, and what are the key facts about its evolution?

Answer 18

The layer above the cerebrum (including both hemispheres) which controls voluntary actions, cognition, and perception awareness.

• Mammals have a more complex 6-layer structure (neocortex)
• Number of neurons related to ‘intelligence’
• Although they may have different sizes, they’ll have the same general structure

Question 19

The four lobes of the cerebral cortex

Answer 19

Frontal - at the front
Parietal - to the right of the frontal, above temporal
Occipital - to the right of temporal, below parietal
Temporal - above the spinal cord, left of cerebellum

Question 20

The frontal lobe: what does it do?

Answer 20

Control actions, motor, speech control, and emotion

Question 21

The Parietal lobe: what does it do?

Answer 21

Sensory and language

Question 22

The Occipital lobe: what does it do?

Answer 22

Memory, sensory, language

Question 23

The Temporal lobe: what does it do?

Answer 23

Visual

Question 24

Golgi and the reticular theory

Answer 24

Golgi discovered a silver stain allowing neurons to be viewed, his findings led him to believe that neurons fused together

Question 25

Cajal and the neuron doctrine

Answer 25

Using Gogli’s stain, he concluded that neurons were distinct cells that communicated by contact and they only sent information to other neurons

Question 26

Confocal microscopy

Answer 26

The basic principle of confocal microscopy is that the illumination and detection optics are focused on the same diffraction-limited spot, which is moved over the sample to build the complete image on the detector

Question 27

Why do neurons not fall apart despite not having connective tissue?

Answer 27

Neurons are supported by a cell type known as glia

Glia are cells that can divide unlike neurons have the primary job of supporting the nervous system but may also have their own role in signalling

Question 28

Astrocytes: what are they?

Answer 28

Star-shaped cells that are the main type of glia which fill the space between neurons and regulate the composition of extracellular fluid

Can also play an important role in the differentiation and proliferation (increase) of neurons

Question 29

Oligodendrocytes: what do they do?

Answer 29

Myelinate axons on neurons in the CNS

Question 30

Schwann cells: what do they do?

Answer 30

Myelinate cells in the PNS

Question 31

Microglia: what are they and what do they do?

Answer 31

Type of migrating glial cells that act as brain scavengers with phagocytic/immune function

Question 32

Ependymal cells: what are they and what do they do?

Answer 32

They have cilia and their structure resembles epithelial cells with an important role in the production of cerebrospinal fluid

Question 33

Axons features: physiological, organelles, structural, specialisations, and myelination?

Answer 33

Propagate information, synaptic vesicles, long and untapered and branch at 90°, terminal, and often

Question 34

Dendrite features: physiological, organelles, structural, specialisations, and myelination?

Answer 34

Receive information, soma (containing the cytosol), short and tapered and branched, dendritic spines, and none

Question 35

Cystolic organelles

Answer 35

Dendritic organelles:
* Peroxisomes, mitochondria
* Ribosomes
* Vacuolar apparatus (secretory/endocytic pathway):
ER endoplasmic reticulum, secretory vesicles, Golgi complex, endosomes

Axon organelles:
* Synaptic vesicles
* Mitochondria
* Smooth ER

Question 36

Membrane differences between axons and dendrites

Answer 36

Dendrites:
Ca²⁺ channels
GPCRs
Ligand-gated ion channels

Axons:
Na⁺ and k⁺ channels along the axon
Ca²⁺ channels (terminal)
GCPRs (terminal)

Question 37

How does axon/dendrite targetting work?

Answer 37

Mechanism unclear

Question 38

The role of the neuronal cytoskeleton

Answer 38

• Structural support – shape and calibre of axons and dendrites
• Transport cargo to and from axons and dendrites
• Tethering of components at the membrane surface

Question 39

Microtubules in the neuron: what do they do, what are their key features, and what does the moving?

Answer 39

Run longitudinally down axons and dendrites, aiding structural and Transport

• Big, 20 nm wide, tubulin polymers
• Polymerisation/Depolymerisation – shape change

Microtubule Associated Proteins e.g. MAP-2, Tau, Kinesin (moves down towards the terminal axon) & Dynein (moves back up from the axon to the dendrites)

Question 40

Neurofilaments in the neuron: what do they do and what are their key features?

Answer 40

Mechanical strength

10 nm wide filamentous protein threads

Question 41

Microfilaments in the neuron: what do they do and what are their key features?

Answer 41

Mediate shape change

• 5 nm wide, actin polymers
• Tethered to membrane

Question 42

Types of neurons

Answer 42

Sensory (afferent; somatic or visceral) neurons originate from sensory receptors to the ‘processor’

Motor (efferent; somatic or visceral) neurons conduct signals that originated in the CNS

Interneurons are between sensory and motor neurons

Question 43

Decussation

Answer 43

Two things crossing over in an X shape (ie eyesight)

Question 44

What treatments are there for Alzheimer’s disease

Answer 44

• Small molecule drugs which act as acetylcholinesterase inhibitors (donepezil, galantamine)
• Preventing excessive glutamate transmission (N-methyl-D-aspartate (NMDA) receptor blockers)

Question 45

What are the differences in brains with Alzheimer’s and without it: β amyloid, tau, microglia activation, and synaptic function/density?

Answer 45

β amyloid - increases
Tau - increases
Microglia - increased activation
Synaptic function/density - decreases

Question 46

Lecanemab: what is it, what can it be treated for and how may it do this?

Answer 46

A monoclonal antibody obtained by a mouse antibody

Treating AD

Preventing excessive β amyloid deposition