Retinal Anatomy & Physiology Flashcards
What is phototransduction?
when light energy is turned into an electrical signal
What is created when phototransduction occurs?
Energy and Heat
How do we cool down the retina when phototransduction is occurring?
Place it next to the choroid (heat sink)
What’s the #1 reason for choroidal detachment?
Hypotony
What’s the main neurotransmitter for vision?
Glutamate
What are the 4 functions of the mueller cell?
i. Forming the ILM and ELM
ii. Structural Support – found vertically in the retina
iii. Glucose support (energy into the cells)
iv. Picks up excess glutamate
What are the 2 types of glial cells?
Astrocytes and Microglial cells
Where are astrocytes found?
found in nerve fiber layer and ILM
Goes horizontally to support the retina
Where are microglial cells found? What are they activated to become?
- Found in the inner retina, latent
2. Activated to become macrophages when pathogens come into play
What are the 2 neurotransmitters?
Glutamate and acetylcholine
When it comes to blood supply, what supplies the retina?
Central Retinal Artery – supplies inner 2/3 of the retina
Choriocapillaris - outer 1/3 of retina
How is the retina blood supply controlled?
By Autoregulation - receptors tell BVs to constrict or dilate based on oxygen need
What is the choroid supplied by? What part of the nervous system controls it?
Short posterior ciliary arteries
- Controlled by sympathetic nervous system
Why does the retina live on starvation mode and have a very low blood supply?
- we want it to stay transparent
- decrease amount of free radicals (oxygen + blue light = FR)
What pigments are there to block the blue light and fight free radicals
Xanthophylls
Lipofuscin
Melanin - in RPE
WIT: Pigment that has the highest blue light filtering mechanism
Lutein
WIT: Pigment that blocks the oxygen
Zeaxanthin
In glaucoma, what cell is destroyed?
Ganglion Cell
What keeps the 9th layer semi-attached to the 10th layer?
i. IOP
ii. Thick vitreous (weight of the vitreous)
iii. Sodium Pumps
iv. Inner PR matrix
What part of the retina is the thickest?
Macula area
What are the 2 avascular portons of the retina?
- Ora Serrata
2. Foveola Region
How many capillary networks are found in the retina?
- Radial Peripapillary CN
- Superficial CN
- Deep CN
Where is the radial peripapillary CN found? What retinal changes are found there?
Found underneath the internal limiting (IL)
- CWS and flame hemorrhages from HTN are found here
Where is the superficial CN found? What retinal changes are found there?
Found in NFL and ganglion cell area
Possible flame hemorrhages found here
