Physiology Flashcards
What is the conjunctiva?
A mucous membrane covering the sclera and inside of the eyelids
What part of the eye provides the majority of the focusing power?
The cornea
Describe how the lens of the eye changes shape
When focusing, the ciliary muscles contract
How does the ciliary fibres interact with the lens?
via attachment by Zonule fibres
What is the cornea made out of?
Collagen (continuous with the sclera)
What is the aqueous humour?
Transparent gel like fluid which fills the anterior part of the eye between the lens and the cornea
What is the purpose of the aqueous humour?
Maintains intraocular pressure (IOP), nourishes and removes debris from anterior portion of the eye
How does the aqueous humour return to the bloodstream?
via. the trabecular meshwork in the superior anterior section of the eye
What is glaucoma?
when the trabecular meshwork degenerates so the IOP increases as the aq. humour cannot be drained
What is the sclera made from?
Type I collagen
What is the choroid?
The vascularised connective tissue layer, contains melanin
What are the 2 humours in the eye?
The aq. humour (in the anterior) and virtuous humour (filling up the posterior part of the eye
True or false: the photo-receptors are the last of the neuronal layers to be hit with light (e.g. are at the back)
True
What is the first layer of the retina?
Retinal Pigment Epithelium, single layer of cuboidal pigment cells that are tightly attached to each other providing part of the outer blood–retinal barrier. The RPE cells contain melanin, used too ‘soak up’ stray photons so they can’t interact and discrease resolution
What is the second layer of the retina?
The photoreceptor layer that contains the rods and cones
What is the third layer of the retina?
External limiting membrane, junction between the processes of the muller cells and the photoreceptor cells
What is the fourth layer of the retina?
Outer nuclear layer, contains the nuclei and cell bodies of the photoreceptors
What is the fifth layer of the retina?
Outer plexiform layer, composed of the synapses of the photoreceptor cells with the biopolar cells and the horizontal cells
What is the sixth layer of the retina?
Inner nuclear layer, consists of nuclei and cell bodies of muller cells, bipolar cells and amacrine cells
What is the seventh layer of the retina?
Inner plexiform layer, site of synapses between bipoolar and ganglion cells, action site for amacrine cells
What is the eight layer of the retina?
Ganglion cell layer, where the ganglion cell bodies are