The 4 tissue types Flashcards
What are the 2 main types of glands?
Endocrine
Exocrine
What is an endocrine gland?
secretion into blood stream
What is an exocrine gland?
secretion into ducts
Modes of glandular secretion - exocrine?
Merocrine
Apocrine
Holocrine
How is merocrine secreted?
Via exocytosis
How is apocrine secreted?
tip of cell is shed as they accumulate in the apex of the cell then break off.
How is holocrine secreted?
whole cell ruptures
What are the types of glandular secretion?
Mucous -sticky
Serous- watery
Sebaceous- oily
How does mucous cell appear?
cells stain light
How does serous cells appear?
dark
How can exocrine glands be classified by structure?
their division into unicellular and multicellular
What is the lining of the eye inside?
pigmented by melanin
WHy is the inside of the eye pigmented by melanin?
serves to absorb stray light and improve image quality
What is a unicellular gland?
Goblet cell
What do goblet cells produce?
mucous
Where is mucous secreted into?
The lumen
Where are numerous amounts of goblet cells?
within the conjunctiva
What do conjunctival goblet cells form ?
The mucous layer of the tear film
Why is goblet cell important ?
It sticks the mucous layer in the tear film
What do the goblet cells do in the gut?
Protect and lubricate
What are multicellular glands?
consist of groups of secretory cells connected to the body surfaces by ducts.
What are simple multicellular glands?
have a single duct
What are compound multicellular ducts?
have several ducts
What is an example of a simple multicellular gland?
The meibomian gland of the eyelid
Whats the structure of the meibomian gland?
One duct with many secretory cells
What does the meibomian gland form?
The lipid layer of the tear film
What is a non-ocular example of simple multicellular gland?
those found at various points of the DIGESTIVE TRACT such as COLON
What is an example of compound multicelluar gland?
the lacrimal gland
What is a acinar compound gland?
lacrimal gland
What does the lacrimal gland secrete?
the aqueous layer of the tear film
What are the 4 basic types of connective tissue?
cartilage
blood
bone
connective tissue proper
What are the 3 things connective tissue made from?
ground substance
fibres
few cells
What are the 3 connective tissue FIBRES?
Collagen
Elastic
Reticular
What is the most abundant fibre and why?
Collagen because it counts for 30% dry weight as its the most thickest , with a high tensile strength and unstretchable
What is the elastic fibre?
Composed of elastin
stretch readily and return to their original form
What is reticular fibre?
very fine collagen fibres
What are the connective tissue proper CELLS?
Fibroblasts
What is the connective tissue proper GROUND SUBSTANCE?
background substance which consists of glycoproteins in which other elements of the connective tissue are suspended .
Why is a fibroblast a fundamental cell type of connective tissue proper?
as they secrete the fibres and the ground substance
They are often 2D and wide
What happens if fibroblasts become activated?
They make ground substances if injured
What is the stroma of the cornea made up from?
tightly packed collagen fibres
How does the fibroblast appear?
darker areas are fibroblasts which are usually sandwhiched between the collagen
What are the connective tissue proper cells?
plasma cells- which produce antibodies
macrophages- phagocytosis
mast cells- produce histamine
What is connective tissue divided into?
Loose - fibres loosely arranged
dense- fibres are densely arranged
What is loose aereolar connective tissue?
acts as packaging material
light and soft and most widely distrubuted
it traps fluid ( causing bruising)
An example of loose aereolar is?
stroma of the iris - allows to change shape of pupil
What is loose adipose connective tissue?
largely made up of fat cells (adipocytes)
What do loose adipose tissue appear as?
as white spaces due to all organelles being pushed to the sideand virtually the whole cell is occupied by fat droplet
What does fat serve as?
energy store
insulation- thermoregulation
protection (shock absorber)
Where is an obvious location for fat cells?
Under the skin
also surrounds the lacrimal gland
What area does the fat surround?
around the outside of the eye- it acts as a cushion
What are dense regular connective tissue?
compact tissue
regularly arranged collagen fibres as the main component
high tensile strength
A good example of dense regular tissue>
Tendon- which attached muscle to bone
What is dense irregular tissue?
less regularly arranged collagen fibres
How is dense irregular different to dense regular tissue?
As the collagen fibres are arranged in different directions there is strength in all different directions
An example of dense irregular tissue?
Skin
How is the collagen arranged in the corneal stroma?
dense regular which is what makes it transparent
How is collagen arranged in the sclera?
irregular which means its structure is opaque and not transparent.
What are other examples of goblet cells in structures?
trachea
ducts of salivary glands
