Lecture 2 - part 2 - Glandular epithelium and connective tissue Flashcards
What are the 2 types of gland
- Endocrine - secrete into blood stream
- Exocrine - secrete into ducts
Modes of glandular secretion
- Merocrine - secreted via exocytosis
- Apocrine - tip of cell sheds - breaks off
- Holocrine - whole cell ruptures
Types of glandular secretion
- Mucous - sticky - stains lightly
- Serous - watery - stains darkly
- Sebaceous - oily
What gland secretes mixed
Lacrimal gland
mucous and serous
What can glandular exocrine glands be split into
- Unicellular glands
- Multicellular glands
What is example of unicellular gland
Goblet cells
Which ocular tissue contains goblet cells and why?
Conjunctiva in the upper eyelid.
In the conjunctiva goblet cells are a source of mucin in tears and they also secrete different types of mucins onto the ocular surface.
Mucus binds aqueous and tear film in your eye + Secrete proteins
Role of goblet cells
Produce mucous
Where are goblet cells found
Conjunctiva
What forms the mucous part of tear film
Conjunctival goblet cells - cover posterior ( back )surface of eyelids and exposed surface of eye (limbus)
What do goblet cells have
triangular nucleus + large lumen
What are multicellular glands divided into
Simple ( one duct )
Compound ( several ducts ) - bundles of secretory cells
Each duct has secretory units - secrete substances into guts
What is example of simple multicellular gland
tarsal gland - found in upper and lower eyelids
They open onto the ocular surface via pores at the eyelid margin
What is example of multicellular compound gland
Lacrimal gland
what part of tear film does lacrimal glands secrete
Aqueous component - serous secretions
What part of tear film does tarsal gland produce
Lipid layer - oily
What is connective tissue
- Acellular
- Consists of:
- Ground subsntance
- Different types of fibres
- Small number of various types of cell
What are 4 types of connective tissue
- Cartilage
- Bone
- Blood
- Connective tissue proper
What is ground substance
background substance ( consisting mainly of glycoproteins and proteoglycans ), in which the other elements of connective tissue are suspended
What does ground substance do
Suspends fibres
What are the different types of fibres
collagen - thickest and strongest, unstrechable
elastic - thinner than collagen, recoils
reticular - thicker than elastic, thinner than collagen, type of collagen
What are the different types of cells in connective tissue
- Fibroblasts
- Plasma cells - produces antibodies
- Macrophages - phagocytosis
- Mast cells - inflammatory response
What are fibroblasts
- Secrete fibres and ground substance
- Thermal insulation,
- Energy store
- Protection against mechanical shock
- Often 2D and flat
Where are fibroblasts found
stroma of cornea - tightly packed collagen fibres
What fibres are secreted by fibroblasts
collagen
What is connective tissue divided into
Loose - fibres loosely arranged
and Dense - fibres densley arranged
Loose connective tissue
Aereolar
Adipose
Dense connective tissue
Regular - specific order, same diameter
Irregular - randomly arranged, varying diameters
Loose areolar connective tissue
Packaging material of body
soft and pliable
most widely distributed type of connective tissue
traps fluid
light, fluffy, air
loosely arranged - lots of air pockets - like cotton wool
Where in the eye do you find aereolar connective tissue and why
The stroma (body) of the iris allows it to change shape - pupil expands- contracts easily - iris changes size as muscles contract to alter size of pupil
Loose adipose connective tissue
Made up of fat cells - adipocytes - appear as white spaces as all organelles have been pushed to the side and whole cells occupied by fat droplet
What are the functions of adipose connective tissue?
Thermal insulation
Energy store
Protect against mechanical shock
What adipose connective tissue is associated with the eye?
Around outside of eye – surrounds lacrimal gland.
Dense regular connective tissue
- Compact
- Regulary arranged collagen fibres
- Strong
- Collagen fibres same size and same direction
what is an example of a dense regular connective tissue
The corneal stroma
Regularly arranged collagen - makes it transparent
Dense irregular connective tissue
- Less regularly arranged collagen fibres and keratin
- Different sizes and directions
what is an example of a dense irregular connective tissue
Sclera
Irregularly arranged - makes it opaque
Summary of connective tissue proper in eye
Loose..
Areolar: Iris
Adipose: Lacrimal gland
Dense....
Regular: Corneal Stroma
Irregular: Sclera
