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Flashcards in Neuroscience Deck (237)
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1

What are the developmental milestones in development?

- By 3 weeks there is eye formation

- 10 weeks = cerebral expansion + commissures

- 3 months = basic structures established 

- 5 months = myelination has begun

- 7 months = lobes cerebrum has formed

- 9 months = gyri + sulci formed

2

What are some critical periods in development?

- Abnormalities to CNS are dependent on time of infection

- 6th week = eye malformations occur, e.g. cataracts

- 9th week = deafness can occur, e.g. malformation of the organ of Corti

- 5th to 10th week = cardiac malformation occurs

- In general, CNS disorders occur in the 2nd trimester

- Risk of disorders falls after 16 weeks due to the fact that most of the structures of the CNS have developed by this time

3

How can increases in neural activity be detected by a lumbar puncture?

- Increases in neural activity results in the increase in the release of neurotransmitters + their associated breakdown products, this can be detected in the CSF by lumbar puncture 

4

What do more neurally active regions require? 

- More neurally active regions require more O2 + thus more blood, this is the basis of modern imaging techniques as they detect haemodynamic changes

5

What does an EEG give an indication of?

- EEG gives an indication of regional brain activity underlying electrodes

- Sensitive to activity in the temporal regions but less sensitive to those in the spatial regions 

- EEG is good at detecting signs of epilepsy

6

What are the two types of muscle fibres? 

- Slow twitch 

- Fast twitch, 2a = glycolytic and oxidative (intermediate), 2b = glycolytic (white)

7

What is a motor unit? 

- A motor unit is made up of a motor neuron + skeletal muscle fibres innervated by that motor neuron's axonal terminals

- Groups of motor units often work together to coordinate the contractions of a single muscle 

- Loss of innervation causes fibre atrophy

8

What are mitochondrial cytopathies?

- Mitochondrial cytopathies = heterogenous group of multisystem disorders which preferentially affect the muscle + nervous systems

- They are either caused by mutations in the maternally inherited mitochondrial genome, or by nuclear DNA mutations

9

What are dystrophies? 

- Dystrophies are genetically determined, destructive + mainly progressive disorders of muscle

- Many types, defects of proteins that confer stability to the sarcolemma are one group of causes

10

Membrane stain of dystrophin.

11

What are the 3 layers of the eye? What do they contain?

- Fibrous (outer) layer = cornea + sclera

- Vascular (middle) layer = iris, ciliary body and choroid

- Inner layer (retina) 

12

What is the humour called in the anterior and posterior chamber? How about the rest of the eye?

- Anterior and posterior chamber = aqueous humour (thin, transparent fluid, 99.9% water)

- Rest of the eye = vitreous humour (clear gel)

13

What is the fibrous layer comprised of? What do these do?

- Made up of cornea + sclera 

- Sclera = tough fibrous outer coat, made of collagen, 85% of layer

- Cornea = made of collagen, part of fibrous layer over pupil + iris so transparent 

14

What is the vascular layer comprised of? What do these do?

- Vascular layer comprised of choroid, ciliary body (ciliary muscle + ciliary processes) and iris

- Iris = coloured part of the eye. Controls the size of the pupil through dilator and sphincter papillae muscles 

- Ciliary body (ciliary muscle + ciliary processes) = controls size of lens and forms aqueous humour

- Choroid = connective tissue + blood vessels, blood supply to outer third of retina

15

When the ciliary muscles contract, what happens?

Ciliary muscle contracts, suspensory ligaments relax, this relaxes tension on lens + lens becomes more rounded 

16

What do the sphincter papillae and dilator papillae do? What are these innervated by? 

- Sphincter papillae = constricts the pupil = PARASYMPATHETIC (oculomotor CN)

- Dilator papillae = dilates the pupil = SYMPATHETIC 

 

17

What is in the inner layer?

- Retina

- Two parts: optic part (light sensitive) + nonvisual part (covers internal surface of ciliary body and iris)

- There are many layers to the retina
 

18

What are the layers of the retina? What is found within them?

- Pigmented layer

- Neural layer:

- Photoreceptors. RODS = function in dim light + are insensitive to colour. CONES = respond to bright light and sensitive to colour 

- Bipolar cells

- Ganglion cells = synapse in the lateral geniculate body

19

What are the layers through which a photon must travel through the eye?

- Tear film (3 layers: anterior lipid, middle aqueous and posterior mucous)

- Cornea (transmission + refraction) 

- Aqueous humour

- Lens

- Vitreous humour 

- Ganglion cell

- Amacrine cell

- Bipolar cell

- Horizontal cell

- Cone

- Rod

- Pigmented epithelium (absorption of excess photons) 

20

What are the two main different cell types in the CNS?

- Neurons

- Glial cells (provide support + protection for neurons = glue)

21

What are some different types of glial cells? 

- Oligodendrocytes

- Microglia

- Astrocytes

22

Picture of a neuron.

23

What are neurons used for? Where do they mainly develop?

- Specialised for intercellular electrical signalling via synapses

- Dendrites receives inputs (dendritic spines), transmit to cell body (soma)

- Action potentials propagate along axon

- Mainly develop during brain development 

24

Neurons communicate via synapses. What are the two types?

- Chemical (majority)

- Electrical (less abundant, enable synchronised electrical activity)

25

What are oligodendrocytes? 

- Myelinating cells of the CNS

- Myelin insulates axon segments, allows rapid conduction

- Myelin sheath interrupted by nodes of Ranvier = saltatory conduction

26

How are oligodendrocytes different from Schwann cells?

- Schwann cells = PNS, oligodendrocytes = CNS

27

What are microglia? 

- Resident immune cells of CNS

- Upon activation, become amoeboid + mobile

28

What are astrocytes? What are the 3 types?

- Most numerous cells in the CNS

- 3 types = radial glia, Bergmann glia + Müller cells

 

29

What are the two forms of astrocytes?

- Fibrous = white matter, contact blood vessels, pia + nodes of Ranvier

- Protoplasmic = grey matter, contact blood vessels + pia

30

What are the functions of astrocytes?

- Contribute to blood-brain barrier

- Structural - define brain micro-architecture

- Envelop synapses

- Homeostatic