Cells and Tissues of the Nervous System Flashcards
Outline the five histological layers of the cornea
- Stratified squamous, non-keratinised epithelium
- Bowmann’s membrane (basement)
- Stroma
- Descment’s Layer
- Endothelium - simple squamous
What is the stroma of the cornea made of?
Avascular connective tissue
How is the cornea transparent?
- Regular arrangement of storm
- Avascular
- Liquid components are transparent
Why is the cornea considered an immune privileged site?
Avascularity means less likely to be rejected
What is the ciliary body?
A muscular network that suspends the lens in place
What does the ciliary body consist of?
- Trabecular network of muscle that holds the lens in place
- Schlemm’s canal, the aqueous humour outflow
What are the important layers of the retina?
- Pigment epithelial layer
- Rods and cones layer
- Nerve fibre layer
What is the choroid?
Made up of fenestrated good vessels of varying diameter supplying the outer layers of the retina with blood through diffusion
Where does the inner retina gets its blood supply from?
The central retinal artery
What is the lens of the eye?
The transparent, biconvex crystalline structure that can change its shape to accommodate vision.
What pathology does the avasculairty of the lens dispose it to?
Glaucoma (opacification)
What are the functions of the lacrimal apparatus?
- Keep cornea moist
- Wash away foreign bodies
- Lyse pathogens
- Smooth the surface of the cornea for optimal light refraction
How is the tear film exposed in a clinical setting?
Fluorescein dye
Describe the innervation resulting in secretion of tears
Parasympathetic (CN VII) secretes tear into conjunctival sac
Describe the layers and distribution of the tear film
- Mucinous layer (30%)
- Aqueous layer (69%)
- Oily layer (<1%) (most superficial)
