Histology of the Eye and Visual Tracts (Dennis) Flashcards
What are tarsal glands?
What are sebaceous glands
What are lacrimal glands?
Special sebaceous, secretion results in evaporation of tears (blockage = chalazion) Eyelash gland (infection = stye) Produces tears
Where is the palpebral and bulbar conjunctiva?
Palpebral is on the lid, bulbar is on the outer surface of the eye itself
Label the chambers of the eye (also on anatomy drawing):
Ok
What is included in the fibrous tunic of the eye? What are they made of ?
Sclera - dense irregular
Cornea - two epithelium layers with connective tissue sandwiched in between
What is included in the vascular tunic/uvea of the eye? What are they made of?
Choroid - vascularized areolar connective tissue
Ciliary body - ciliary smooth muscle and ciliary processes covered with secretory epithelium
Iris - 2 layers of smooth muscle (dilator and sphincter pupilae) and connective tissue + central pupil
What is included in the retina of the eye? What are they made of?
Pigmented layer - pigmented epithelial cells
Neural layer - photoreceptors, bipolar neurons, ganglion and supporting Muller cells
Properties of the sclera and the cornea
Sclera has fibrous opaque layer
Cornea has 5 layers and is continuous with sclera
What is the corneal epithelium?
Layer 1 of cornea - nonkeratinized stratified squamous
What is the bowman’s membrane?
Layer 2. sandwiched between the anterior basement membrane and the corneal epithelium
What is the corneal stroma?
Layer 3 of the cornea. Avascular
What is the Descemet’s membrane?
Layer 4 of cornea. Sandwiched between the posterior basement membrane and the corneal endothelium, very thick
What is the corneal endothelium?
Layer 5. simple squamous facing the anterior chamber
Vascular coat of the eye includes ….
Choroid, ciliary body and iris
Choroid features:
Has an inner vascular layer called the choriocapillary
Bruch’s membrane (ECM layer)
Ciliary body features:
Has ciliary muscle (lens accommodation) and ciliary process (secretes aqueous humor, forms the suspensory ligaments of the lens)
Iris features:
Is a contractile diaphragm in front of the lens, has dilator (radial band) and sphincter (circular band) pupillae
Lens components
Transparent and avascular
Capsule - made of elastic ECM
Subcapsular lens epithelium - periphery cells migrate to make mature lens fiber cells
Lens fibers - has cystallins and lost all organelles
Describe accommodation
Adjustment of the eye for seeing objects at various distances.
Ciliary muscle controls the lens (via flattening or thickening) for near and far vision.
Flat lens - see further (sympathetic)
What is presbyopia?
Loss of lens elasticity with age