Fm2101 - Biochemistry- Lecture 1

Front 1

Key characteristics of neurons

Back 1

Morphology-

- Axons and Dendrites

- Connections

- Synapses

Electrical properties

- Action Potential

Post mitotic

- Can't undergo cell division

Front 2

Cytoskeleton Component's

Back 2

~ Micro filaments (Actin)

~ Intermediate Filaments

~ Microtubules (Tubulin

Front 3

Function of Microfilaments

Back 3

Major cytoskeletal element @ synapses

Involved in growth of axons and dendrites during NS development

Front 4

Function of Intermediate Filaments - Neurofilaments

Back 4

Prominent in Axons

- Structural role

- No polarity

- No motor proteins

Front 5

Function of Microtubules

Back 5

Involved in Transport of molecules, Vesicles and Organelles

~ Unipolar in axons

~ Multipolar in dendrites

Front 6

Cytoskeleton - Monomers

Back 6

Globular (G) Actin

Tubulin (a/b)

Front 7

Cytoskeleton - Polymers

Back 7

Actin Filaments (F-Actin)

Microtubules

Both dynamic compared to Intermediate Filaments

Front 8

Microtubule Associated Proteins - MAP's

Back 8

Tau - Predominantly in Axons

~ binding regulated by phosphorylation

- ~ Hyperphosphorylation = pathogenic role in Alzheimers Disease

MAP2 - Only in Dendrites

MAP4

Front 9

Motor proteins

Back 9

Transport cargo along Microtubules and actin filaments

- Kinesis and Dyenins in microtubules

- Myosin in Actin Filaments

Front 10

Myosin role in Cytoskeleton

Back 10

Motor proteins in Actin filaments

Front 11

Kinesins and Dyenins role in cytoskeleton

Back 11

Motor proteins in Microtubules

Front 12

Dendritic Spine

Back 12

Knob-like protrusion from dendrites

Major sites of synapse formation in many neurons

Front 13

Neurites

Back 13

Axon/ Dendrite

Grows from cell body

Find targets in response to poitive/ negative guidance cues

Front 14

Actin role in microfilaments

Back 14

Synaptic plasticity

Dendritic outgrowth

Axon Guidance

Front 15

Molecules that guide axons and migrating cells during brain development

Back 15

Receptors- transmembrane

Soluble and/or membrane bound ligand

- produced by other neurons/ neuroglia

Attractive and repulsive Signals

Signals usually transmitted to actin or microtubule based cytoskeleton

- actin via Rho family via GTPases

Front 16

Defects in axon guidance

Back 16

Horizontal gaze palsy w/ Progressive scoliosis

~ V.rare autosomal recessive disorder caused by mutations in Robo3 axons in the pons and medulla

~ Abnormal decussation (midline disorder) of axons in pons and medulla

Congenital fibrosis of the extraocular muscles (Type 1)

~ Caused by mutations in KIF21A - coding for a kinesin Microtubules motor proteins

~ Bilateral blepharoptosis (drooping eyelids) and strabismus,

- - absence of fusion and binocular vision.

- - The eyes look down at rest, and cannot be elevated

- - Variable horizontal movement.

Front 17

Horizontal gaze palsy w/ Progressive scoliosis

Back 17

Horizontal gaze palsy w/ Progressive scoliosis

~ V.rare autosomal recessive disorder caused by mutations in Robo3 axons in the pons and medulla

~ Abnormal decussation (midline disorder) of axons in pons and medulla

Front 18

Congenital fibrosis of the extraocular muscles (Type 1)

Back 18

Congenital fibrosis of the extraocular muscles (Type 1)

~ Caused by mutations in KIF21A - coding for a kinesin Microtubules motor proteins

~ Bilateral blepharoptosis (drooping eyelids) and strabismus,

- - absence of fusion and binocular vision.

- - The eyes look down at rest, and cannot be elevated

- - Variable horizontal movement.

Front 19

ATPase powered pump

Back 19

Protein - Sodium Pottasium ATPase

3na+ out

2k+ in

Generates gradient

Front 20

Extracellukar/ intracellular ion concentrations

Back 20

Intra:Extra

Potassium - 140 : 5

Sodium - 5/15 : 145

Chloride- 4/30 : 110

Calcium- .0001: 1-2

Front 21

Typical membrane resting potential

Back 21

-70mV

Front 22

Action Potential

Back 22

Electrical impulse travels from cell body through to axon

Caused by voltage sensitive Na+ and K+ channels opening and closing briefly