Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Neural Biology 1 > eye development 1 > Flashcards

eye development 1 Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What is the most key thing during development (embryology )?

A

during week three you get -Gastrulation - where you have cells which have potential to differentiate into any tissue in your body, becoming partly differentiated .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does gastrulation do ?

A

split into 3 germ layers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 3 germ layers ?

A

Outer ectoderm
middle mesoderm
inner endoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the cells like in the germ layers ?

A

are no longer pluri-potent ‘stem cells’ capable of generating any cell type in the body, but have now become committed to producing only a restricted set of cells & tissues (known as their ‘derivatives’).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the outer ectoderm ?

A

a columnar epithelial cell

-produce outer epithelia and your CNS and PNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the middle mesoderm ?

A

fibroblast-like cells and fibres

-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the middle mesoderm ?

A

fibroblast-like cells and fibres

  • have more of a connective tissue like structure
  • form muscles to bones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the inner endoderm ?

A

cuboidal epithelial cells

  • form inner epithelial cells i.e lining the gastrointensital tract and respiratory tract
  • also some of those epithelial derived organs such as your liver
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the majority of our bodies made up of ?

A

mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the eye derived from ?

A

ectoderm and mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the adult eye structure ?

A

Spherical, 3-layered, fluid-filled capsule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the 3 layers of eye?

A

Inner Layer: Retina (optical, ciliary) + Lens
= Epithelia: from Neural- & Surface- Ectoderm
-lens also surface ectoderm -

Middle Layer: Choroid, Ciliary Body, Iris
= Connective (vascular), Muscle: from Mesoderm

Outer Layer: Sclera, Cornea, Eyelids, Muscle
= Connective tissues: from Mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the inner layer derived from of the eye ?

A

ectoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the middle and outer layer derived from of the eye ?

A

mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does the eye develop firstly ?

A

it is derived from your ectoderm as they give the groundwork/basic structure- such as neural sensory bit, retina , lens etc then mesoderm comes after and fills around it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How is the eye developed ?

A

inside out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the first appearance of the eye ?

A

Inside the eye - (1) Early Embryonic developers, weeks 4-5
Retina (+ Optic Nerve) from the Brain!
Lens, Primary Vitreous + Hyaloid blood vessels (mesoderm bit)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the 2nd first appearance of the eye ?

A

OUTSIDE REGION - (2) Later Embryonic developers, weeks 6-8

Chambers, Coats, Adnexa, EOMs, Orbit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the 3rd first appearance of the eye ?

A

INSIDE - (3) Late developers, Fetal period - 8 weeks

Ciliary body & Iris ( formed at fetal period )

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the retina in the body ?

A

a sensory organ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Where is the retina derived from ?

A

CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What happens if you damage neurones in you PNS?

A

they can regenerate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What happens if you damage neurones in you PNS?

A

they can regenerate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What happens if you lose or damage a neurone in your CNS?

A

it cannot regenerate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What happens during development if you have a disease/ genetic abnormality?

A

it will affect your brain

  • which means embryo is non-viable therefore won’t develop. (aborted)
    i. e with retina - cause vision problem severely -
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the central region called ?

A

nectoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What does the ectoderm do ?

A

has 3 distinct regions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What do the 3 distinct regions do ?

A

they create 3 tissue types derived from the ectoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What do the external regions of the ectoderm form?

A

they form the surface ectoderm- all of outer epithelia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What do the central region form?

A

becomes neural plate

-which forms CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are the tiny regions between surface ectoderm and neural plate?

A

they form as the neural crest and then goes onto form PNS and melanocytes in your skin and uvea

32
Q

How is the notochord made ?

A

triggered through a process of maturation of mesoderm

  • forms notochord
  • then notochord starts releasing growth factors which then stimulates this central region of ectoderm To develop and perforate into neural plate
  • then the concentration decreases as you go externally from notochord
  • then triggers the 2 small region to become neural crest cells
33
Q

What do the cells are not influenced by the notochord become?

A

surface ectoderm

34
Q

What happens at 17 and 18th day ?

A

the surface ectoderm and neural crest start to migrate upwards away from notochord

  • then have neural plate invigilating (a duo) going down toward notochord
  • this forms the neural groove
35
Q

What happens day 20?

A

neural groove comes up and tried to close the loop

  • surface ectoderm pinches of and forms a single sheet across the top
  • they then becomes these green cells (shown on diagram) which are future neural crest ells -these pinch off and migrate to mesoderm
  • leaves neural plate to pinch off becoming cylinder running al long the axis of our developing organism - which then forms our neural tube
36
Q

What else happens in day 20 ?

A

maturation of mesoderm - somites being formed - which forms vertebrael column
-mesoderm differentiates into bones and muscles in tissues surrounding.

37
Q

What happens by day 24?

A
  • turned from cylindrical structure- looking more like an embryo
  • loads of folds going on
  • have optic primordial being formed
38
Q

What is the optic primordium ?

A

where the eye is formed In the embryo

39
Q

Formation of the Neural Tube & Crest: the origins of the Nervous System SUMMARY

A

(1) Neurectoderm of the Neural Plate
Invaginates to form the Neural Groove, flanked by
(2) The Neural Folds
These move together, unite & fuse to form
(3) The Neural Tube: which
Gives rise to the CNS = Brain & Spinal Cord
Including Retina + Optic Nerve
(4) Some Fold cells migrate laterally either side of the Tube =
(5) The Neural Crest: which gives rise to/ go on toFORM
The PNS: Sensory + Autonomic Ganglia & Peripheral Nerves (& Schwann Cells)
And contributes to some ocular tissues, including the melanocytes (pigmented) of the uveal tract

40
Q

So what is the result of this ?

A

neural tube being formed

41
Q

What does the neural tube do

?

A

precursor to CNS, spinal cord , our brain and retina

  • neural part of your eye
  • this then kicks off earl
42
Q

What happens in week 3 ?

A

gastrulation

43
Q

What happens in week 5 ?

A

folding to form embryo eventually

-thats when we get the first outshoot of retina optic nerve

44
Q

What happens before neural tube forms ?

A

still got neural groove

-at forebrain region- we have 2 optic grooves and these occur at day 22

45
Q

What happens at day 22 ?

A 
optic grooves (sulk) appear in the lower wall of forebrain vesicle 
-this then goes onto form the neural tube
46
Q

What happens in day 24?

A

The sulci Evaginate (balloon outwards) forming the Optic Vesicles attached to the Forebrain by an Optic Stalk
(–the same time neural tube is closing we have optic grooves growing and expanding and become a vesicle )

47
Q

What happens in day 30 ?

A

Day 30: The Outer face of Optic Vesicles (the ‘Retinal Discs’) thicken & contact the Surface Ectoderm
-mesoderm migrate out of the way, and these optic vesicle grow until they become in contact with our surface ectoderm - when they make contact this region at the forefront of optic vesicle start to thicken- known as retinal disc- which is the tissue which later becomes the retina

48
Q

What happens in day 31?

A

Day 31: The retinal discs Invaginate (move inwards) forming the bi-layered Optic Cups & the Optic Stalks begin to narrow

49
Q

What is lens placoude?

A

as the retinal disc forms, the surface ectoderm starts to thicken

50
Q

What does the the outer layer of the Optic Cup develops in to ?

A

the Retinal Pigment Epithelium (RPE), the inner (retinal disc) layer becomes the Neural Retina, & the Optic Stalk develops into the Optic Nerve

51
Q

W

A

this region where you develop retina

  • binds to forebrain part of your neural. tube- which starts to narrow and pinch together
  • this region will come close but not become separate
  • this is because it is the fore runner for your optic store / optic nerve
52
Q

What happens where you’re retinal disc is?

A

it is invagination and migrate its way into filling and forming into a cup

  • now this is the retina on the sides of that area- which are going to become your retinal pigment epithelial
  • so got your cup , neural retina inside, outside have part of your retina which is the retinal pigment epithelium - this region forms the future optic nerve
53
Q

What occurs with invagination region?

A

the retina forms

54
Q

What are the 2 layers of the optic cup separated by ?

A

an ‘intra-retinal’ space,

55
Q

What is the intra retinal space ?

A

which is continuous with the central cavity of the Optic Stalk leading to the forebrain ventricles. Hyaloid blood vessels enter the Optic Cup via a ventral slit (the Optic or Choriodal Fissure) to supply the cells in the developing retina & lens.

  • continous with the ventricle of you forebrain - it contains your fluid in their which feeds these cells
  • retinal pigment epithelium and photoreceptors interdigitate
  • they try get the intra retinal place as minimalas possible - eventually the intra retinal space will be cut off from the ventricles of the brain.
56
Q

What happens when we get closure from intra retinal space ?

A
  • need another supply of nutrients in this region so have growth of blood vessels from our mesoderm
  • have hyoid artery and vein growing up along outside of optic stalk and come through choroidal fissure and how into the centre of the developing cup not intra retinal space but inside the cup itself
  • they go onto form hyloid vascloture inside your optic cup and feed developing lens
57
Q

What happens by 37th day ?

A

once blood vessels grown in - our tissue andengulf developing blood vessels and fuse on the other side to complete seal the cup

  • out choroidal fissure cloys trapping hyloidd vessels inside the developing optic nerve in optic stalk and in vitreous cavity
  • choroidal fissure starts to close around the developing g hyloid vascolutre at 37 day’s
  • optic cup is formed now
58
Q

What is the CNS development : sequence of events?

A

1 -Cell Genesis by Mitosis in Ventricular Zone
Neurons & Glial Cells
now creates a thicker layer of tissue- cells migrate into retina and away from ventricular space (where the cells go through mitosis ) away from sub retinal space and migrate up.

(2) Cell Movement & Migration
Forming cell layers
^ from number 1
(3) Cellular Differentiation
-now cells differentiate
Acquire processes (axons), molecular identity
-form different layers of retina
-first cone photoreceptor and retinal ganglion cells and last cell to be developed would be muller cell.
(4) Cell Death, Apoptosis
Many neurons die during synaptogenesis (connection formation)

59
Q

What is the development of the retina ?

A
  1. Neurogenesis, Migration & Differentiation
    - Neurons born in Outer Neuroblastic Layer at the Ventricular Zone next to Intra-Retinal Space
    - Post-mitotic neurons Migrate to Inner Neuroblastic Layer & Differentiate (e.g. acquire dendrites/axons)
    - First born (from ~day 33): cones & ganglion cells with axons entering Optic Stalk from ~day 42
    - Later born: rods & interneurons (including bipolar, horizontal & amacrine cells)
60
Q

What interdigitate ?

A

retinal pigment epithelium and photoreceptors .

  • they start to interact
  • they try get the intra retinal place as minimalas possible - eventually the intra retinal space will be cut off from the ventricles of the brain.
  • although they are interacting with eachother
61
Q

What is retinal detachemenmtn ?

A

neural retina detaches from the retinal pigment epithelium below it and the intra retinal space is open up again

62
Q

What is the opening at the optic cup on the side ?

A

choroidal fissure

63
Q

What happens after cells differentiate ?

A

they start to take on the characteristics of that cell type
-for example your retinal ganglion cells will start to send out axons
-these axons will start shooting to optic nerve for development
-

64
Q

What happens with neurones that haven’t become part of the network ?

A

they go through cell apoptosis

65
Q

What is the end point ?

A

you end up with the 3 layered retina

  • RPE
  • Outer nuclear layer : (ONL) have photoreceptors : rods and cones
  • Inner nuclear Laye (INL): Interneurones
  • Ganglion cell layer (GCL) : nerve fibre layer
66
Q

What are the ganglion cells doing?

A

shooting axons back up the optic stalk

-send axons back up before we have complete closure of choroidal fissure

67
Q

What happens as ganglion cells mature and they axons are reached the optic disc and sent back through the optic nerve ?

A

get increased density of optic nerve fibres§

68
Q

What else is getting invaginated ?

A

lens primordium/lens placode- which leads to the development of lens

69
Q

How does lens primodium form?

A

Appears start of Embryonic Week 5 (day 30)
Thickening in Surface Ectoderm = Lens Placode (near Retinal Disc of the evaginating Optic Vesicle)

  • Lens Placode invaginates, forming the Lens Pit, which then pinches off from the Surface Ectoderm (day 33) to form Lens Vesicle (inside the moth of the Optic Cup)
  • Placode Induction: was thought to be mediated by retinal disc contact, but now know to occur earlier via factors secreted by Heart Mesoderm
-Lens Maintenance: 
does require contact 
with the retinal disc, 
because lens degenerates
 otherwise
70
Q

What are one of the growth factors of this lens vesicle being formed ?

A

heart mesoderm

71
Q

What is the optic lens vesicle. like ?

A

it is polarised
-during development already has posterior and an anterior face
posterior face - region which faces developing retina
-anterior face- still faces the surface ectoderm

72
Q

What is the first step to develop our lens?

A

posterior face epithelial cells start to elongate and create primary lens fibres.

  • these elongate to day 33 to 47
  • fill space inside lens vesicle
73
Q

What are lens fibres?

A

Lens fibres. These elongate to fill the space inside the lens vesicle.
Once the lens is solid, these primary lens fibres loose their nuclei (to increase transparency and reduce scatter).

74
Q

What happens once fibres developed?

A

primary lens fibres lose all cellular structures and nuclei, create shell
-lose cellular components

75
Q

What happens after the primary lens fibre is lost everything ?

A

you get secondary lens fibres which are your epithelial cells form anterior surface which elongate backwards

  • they create more layers to the lens
  • remain nucleated
76
Q

What is primary vitreous with the TVL?

A
  • THIS IS a developing lens- avascular
  • needs to be fed
  • hyloid vessels come into choroidal fissure and grow into the middle of optic cup - forming primary vitreous
  • start to grow and form a cup around developing lens
  • Develops from mesenchyme & is ‘vascular’ (with a few connective tissue cells & fibres): consists of the hyaloid vessels & tunica vascularis lentis (TVL) on posterior lens face
77
Q

Which of the following statements is true?:

  • The retina develops from an outgrowth from the brain
  • Developing neurons that die from apoptosis do so during their migration from the ventricular zone
  • The choroidal fissure usually closes in week 37 of gestation
  • Primary lens fibres elongate from the anterior face of the embryonic lens vesicle
A

-The retina develops from an outgrowth from the brain

Neural Biology 1 (58 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions