Module 2. - cellular structure of the brain

Question 1

neurons are made of…

Answer 1

epithelial cells of neural plate

Question 2

the cytoskeleton consists of..

Answer 2

microtubules, intermediate filaments, microfilaments

Question 3

nissl substance

Answer 3

rER found in cell body and dendrites, but not axon of neurons

Question 4

ankG protein function

Answer 4

scaffolding protein, proximal axon, nodes

Question 5

Caspr protein function

Answer 5

transmembrane protein, member or neuroxin family, cell adhesion.

Question 6

MAP2 protein function

Answer 6

microtubule associated protein, absent in most astrocytes.

Question 7

mind the gate binding protein

Answer 7

secreted presynaptically, cel adhesion molecules - interact with molecules on surface of adjacent cell.

Question 8

NMDA receptor proteins are inserted into synaptic proteins because?

Answer 8

extra stored in plasmalemmal precursor vesicle (inserted to make bigger or change synapse)

Question 9

Labile cells

Answer 9

cells that undergo mitosis regularly and quickly.

Question 10

cytoskeleton function

Answer 10

internal framework
- shape
- anchoring 
- scaffolding 
stable structure, growth and development.

Question 11

microtubules in dendrites

Answer 11

20-28 diameter

hollow tube of protein tubulin that is made of dimers (alpha and beta). They are polarised (+/-) at both ends.

Question 12

tubulin dimers are added at what end to elongate the microtubule

Answer 12

positive end.

Question 13

process of myelination

Answer 13

neurolemmocyte starts to wrap around axon

its cytoplasm and plasma membrane begin to form layers

wrapping continues

layers of plasma membrane form the myelin sheath

its cytoplasm and nucleus is pushed to the periphery termed neurilemma.

Question 14

intraperiod of myelin

Answer 14

2 inner layers of the plasma membrane and ECS.

Question 15

major dense line in myelin

Answer 15

produced by fusion of cytoplasmic surfaces.

Question 16

axolemma of axon

Answer 16

specialised plasma membrane surrounding axoplasm.

Question 17

axoplasm

Answer 17

cytoplasm of axon.

Question 18

structure of myelin

Answer 18

outer collar - cajal band
inner collar - cytoplasm
periaxonal space - paranodal junctions.

Question 19

internodes are

Answer 19

myelin covered segments from one gap to the next - very stable.

Question 20

juxtaparanodal lies in-between

Answer 20

internode (outermost) and paranodal (innermost)

Question 21

concussion is a ______ force which results in a change in the way you ____ or behave

Answer 21

biomechanics; think.

Question 22

mechanoporation

Answer 22

disruption of cell membranes.

Question 23

neurometabolic cascade of concussion results in a ______ injury. this results in an ionic influx and therefore uncontrollable release of _____. therefore, Ca2+ levels low and impaired oxidation ________

Answer 23

chemical; glutamate; metabolism.

Question 24

Guillain-Barre Syndrome

Answer 24

autoimmune condition that causes acute inflammation of the peripheral nerves in which the myelin sheaths on the axons are destroyed, resulting in decreased nerve impulses, loss of reflex response, and sudden muscle weakness

Question 25

astrocytes influence neural response via ______ release (metabotropic and ionotropic). these receptors allow an influx of ____ ions which in turn activates _____ receptors which induce changes in membrane potential in order for maximal______ between neighbouring synapses.

Answer 25

glutamate; Ca2+; NMDA; synchronous.

Question 26

synchrony of synapses is achieved by glutamate being taken up by neighbouring _____ which diffuses through _____ junctions. subsequently, this releases _______ at a distant synapse and affect underlying neural activity.

Answer 26

astrocytes; gap; gliotransmitter.

Question 27

tripartite synapse

Answer 27

detect activity and influence other neurons.

Question 28

how are astrocytes able to modulate brain junction using examples and explaining structural features.

Answer 28

dominated by intermediate filaments, microtubules and gap junctions. distal feet attached to blood vessels in which communication is achieved via Ca2+ released as waves (Ca2+ binding protein) along astrocyte. release gliotransmitters via exocytosis.

Question 29

describe the tripartite synapses and why it is important

Answer 29

broken down into 3 parts; presynaptic, postsynaptic and astrocyte - ensheathed by an astrocyte, uptake of glutamate NT from the cleft and absorbed. this promotes and increase in Ca2+ within the astrocyte which modulates neural activity via a cascade of events.

Question 30

describe the role of astrocytes in control of blood flow in the brain and discuss why this is important

Answer 30

astrocytes contain end feet which attach to blood vessels - an increase in cognitive demand = increase blood flow, therefore active neurons need energy (glucose, oxygen). astrocytes ensheath synaptic contacts and process glutamate from the cleft via receptors. via signal cascades, Ca2+ is propagates the feet end (high connexin of the astrocyte and release vasoactive metabolites to promote vasodilation/constriction)