week 1 Flashcards
what are glia cells and their function
glia cells are support cells
they help support/protect/insulate neurons
what part of the eye had the most nerve tissues
the retina
3 types of muscle tissue and their characteristics
skeletal muscles - attached to skeleton, striated and generates a lot of force
smooth muscle - lines hollow organs, non striated and capable of sustained activity
cardiac muscle - heart, striated branched fibres and myogenic
what are the 6 extra ocular muscles
superior oblique
inferior oblique
superior rectus
lateral rectus
medial rectus
inferior rectus
what is the function and composition of connective tissue
connective tissue: binds and supports, protects, insulated and stores reserves of elements (H2O, NaCl, fat)
made of ground substance and fibres (extra cellular matrix) and cells
what is the function and composition of ground substance
function: unstructured material that fills the space between cells
composition: interstitial fluid, cell adhesion proteins and proteoglycans and glycoproteins
what are fibres, the 3 types and their characteristics
fibres are strands of proteins
- collagen fibres: thickest, strongest, most abundant and 30% of body’s dry weight of protein
- reticular fibres: forms fuzzy nets to cradle other tissues and very fine collagen fibres
- elastic fibres: thinnest, elastin, stretch readily and return back to og and ideal for supporting moving structures
what are fibroblasts
they secrete fibres and ground substance
almost always 2D - flat and wide
can be seen in stroma of cornea (dark patches between lighter areas of tightly packed collagen fibres)
what are the main classes of connective tissue
specialist connective tissue
connective tissue proper
what are a few differences between loose areolar tissues proper and loose adipose connective tissue
loose areolar: packages material for body, soft, pliable, widely distributed, traps fluid (causes bruising), stores nutrients
loose adipose: nutrient storage, made of adipocytes, white space, organelles pushed to the side and found under skin (for shock absorption and insulation)
what is the function of loose adipose and areolar tissues in the eye
loose aereolar: stroma of iris which helps change shape to control pupil size
loose adipose: fills most of the orbital cavity that’s surrounds most eyeballs, nerves and blood vessels.
surrounds lacrimal glands
what are some differences between dense regular and irregular connective tissue
dense regular: highly fibrous, closely packed bundles of collagen fibres, high tensile strength (binding bones together) and transparent
dense irregular: thicker and irregularly arranged, strength in all directions, useful for skin and certain internal organs
what is keratoconus
it is a condition caused by disorganised lamellae (misshapen cornea)
where are dense regular and irregular tissues function within the eyes
regular: found in the corneal stroma: arranged in 250 sheets (lamellae), parallel to corneal surface, fibres in each lamellae oriented same direction at 90 degrees to adjacent lamellae
irregular: found in sclera and maintains overall eye shape (offers resistance to variety of internal + external forces
what are some functions of epithelial tissue
protection
absorption
excretion
secretion
cleansing
lubrication
what is covering epithelial tissue
lines surfaces of outer body and inner organs. forms tight junctions between adjacent cells and highly innervated by sensory/motor nerve fibres
what are the 3 types of epithelial tissues based on primary shapes and places they are found
squamous - flat and used as a protective layer and found in the cornea
cuboidal - cuboid shaped and found in the kidney
columnar - column likes lines found in the gallbladder
what are the two types of epithelial classes based on number of layers and their characteristics
1- Simple: one layer, useful for substance exchange, basal surface of cornea and allows nutrients in and waste out
2- Stratified: multiple layers, protection, found in areas subject to abrasion and usually squamous (corneal epithelium)
what are the two types of stratified?
pseudo-stratified: stratified appearance but are actually simple and resting on a base membrane (trachea)
transitional: shape isn’t constant, round when organ is relaxed and flatten when distended (bladder)
what is keratinised epithelia
for example in the skin which is composed of dead squamous cells filled with keratin which replaces normal cytoplasm of calls
form white cysts called milia when trapped deposits
what is the use of melanin in the eye
absorbs stray light and improves image quality and mostly foudn in the choroid and retina
what are the 3 main types of cellular composition
serous - watery substance containing proteins (saliva)
mucous - thick and sticky substance (larynx)
sebaceous - oily substance (armpit sweat)
what are the 3 layers of the tear film and what glands produce them
mucous - goblet cells
serous - lacrimal
sebaceous- meibomian
what are exocrine glands
secrete product onto the epithelial surface through a series of connecting cells which form a duct (sweat onto skin)
