Tissue Types Flashcards
What are the 4 tissue types in the body?
- Nervous
- Muscular
- Epithelial
- Connective
What are the 3 ways light can be?
Absorbed
Transmitted
Reflected
How many bones is the orbit made up of?
7
What are the 6 muscles of the eye?
- superior oblique
- superior rectus
- medial rectus
- lateral rectus
- inferior rectus
- inferior oblique
When light rays impinge on the surface of the eye, what does it encounter/hit ?
(photon) hits the tearfilm
What is the outer coat of the eye ?
Sclera (opaque)
What is the front of the eye modified to ?
Transport cornea
What is the corneoscleral junction?
Limbus
After traversing the anterior chamber , what happens to the light
It reaches the lens
How does light focus on the retina?
By the cornea and lens acting together
What is the choroid?
Its is between the retina and sclrera which contains the vascular blood supply to the retina
How are the transparent cornea and lens avascular?
Because they recieve nutrients from the aqueous humour which fills the anterior chamber.
What fills the posterior chamber?
Filled with jelly like vitreous humour
Where are the 2 groups of muscle in the eye?
Iris- which can alter the size of the pupil
Cilary body- change the shape of the lens during the process of accomadation.
What is the bulk of the tear film produced by?
Lacrimal Gland
What tissue makes up most of the retina?
Nervous tissue
What are the nerve cells known as?
Neurones
What structures are the nerve cells associated with in the eye?
cornea (sensory)
cilary (motor)
What are the 2 types of muscle tissue?
Skeletal muscle
smooth muscle
What is the structure of skeletal muscle?
attached to skeleton
striated in appearance
capable of generating a lot of force
What is the structure of smooth muscle?
often found in hollow organs
non-striated in appearance
capable of sustained activity
What are the 2 types of epithelial?
Covering epithelia
Glandular epithelia
What is covering epithelia?
line the free surfaces of the body.
What are the 4 functions of epithelia?
Protection via skin
absorption via digestive tract
filtering via kidney
sensation (taste smell)
What are the shape of epithelial cells?
Usually polyhedral (hexagonal) with strong attachments between adjacent cells
What can the surfaces of the epithelial cells be?
Smooth
-Covered with microvilli or cilia
What does the covering epithelial cell rest on?
Basement membrane
What is epithelial tissue?
Highly regenerative, avascular and can be inervated by both sensory and nerve fibres.
What are the 3 shapes of covering epithelia?
Squamous (flat)
Cuboidal
Columnar
What are the 8 basic types of covering epithelia?
simple squamous
simple cuboidal
simple columnar
pseudo stratified
stratified squamous
stratified cuboidal
stratified columnar
transitional
How many layers are the human cornea?
5
Good example of simple squamous epithelia
Corneal stroma and corneal endothelium
Good example of stratified squamous epithelia?
Corneal epithelihum as it protects from dirt, eyelids.
Where are stratified epithelia usually found?
areas subject to abrasion such as oesophagus and vagina
What is a specialised form of stratified epithelium?
keratinsed epithelium of the skin
What is a transitional epithelium?>
When the cell shape can change.
E.G bladder - epithelia is stretched when bladder is filled.
Why is single layered epithelia not good for protection?
as they are single and are good for areas where the exchange of substances is required.
Other general examples of simple squamous epithelia
lining of blood vessels
alveoli of the lungs
Examples of simple cuboidal
kidney
sebaceous gland
example of simple columnar
gall bladder
cilia
microvili
What is pseudo- stratified epithelium?
All cells sit on the basement membrane appearing startified as all cells are in different shape but is actually simple as they are all the same cells.
what is the adnexa of the eye?
. extra ocular muscle
. conjunctiva
. lacrimal gland
. eyelids
what is conjunctiva?
membrane lines back surface of eyelid and exposed bit of sclera.
stops near the limbus
Where is melanin found too?
in the epithelial cells for skin colour
also many epithelia lining the inside of the eye have melanin
What does the melanin in the eye do?s
serves to absorb stray light and improve image quality.
What are some e.gs of the smooth muscle in the eye?
iris and ciliary body
What are some of the e.g of the skeletal muscle in the eye?
eyelid muscles- e.g obicularis oculi
6 extraocular muscles
