Epithelia

Question 1

What is epithelial tissue?

Answer 1

Lines the external and internal body surfaces. Endothelium is specialist epithelium and lines internal cavities such as the lumen of blood vessels

Question 2

Basal lamina

Answer 2

Foundation to all epithelia. Meshwork made from laminin, type 4 collagen, entacin and perlecan. strong and flexible. Combines with the reticular lamina, which is made of type 3 collagen to form the basement membrane.

Question 3

Basement membrane

Answer 3

Anchors epithelial cells to the connective tissue below, mechanical barrier that creates new blood cells

Question 4

What does the epithelial tissue connect to

Answer 4

Forms a sheet like structure by connecting to neighbouring epithelial cells and the basal lamina

Question 5

Epithelial cells specialised structure= tight junctions

Answer 5

Seal adjacent cells that prevent extracellular substances from moving between them. Also provides cell polarity as the substances cant diffuse from one side of the cell to the other ie glucose

Question 6

Epithelial cells specialised structure= anchoring junctions

Answer 6

Anchor cells to each other and basal lamina. They are categorised by the cytoskeletal filament they interact with. The intermediate and actin filaments run through the cytoplasm, meaning that multiple anchoring junctions help maintain the sheet like structure of the epithelium

Question 7

Epithelial cells specialised structure= actin filament attachments

Answer 7

For actin filament attachments

1) Adherens junction connect cell-cell
2) Focal adhesions connect cell-basal lamina.

For intermediate filament attachment

1) Desmosomes attach cell-cell
2) Hemidesmosomes connect cell-basal lamina.

Question 8

Epithelial cells specialised structure= channel forming junctions (gap junctions)

Answer 8

Allow diffusion and communication between cells. They form channels between adjacent epithelium cells, allowing water soluble ions to move between cells.

Question 9

Stratified squamous

Answer 9

Can either be keratinised or not. It is located at barriers e.g. lumen of blood vessels, mouth, upper throat, oesophagus. It provides protection from the external environment, prevents desiccation and is a covering and lining

Question 10

Simple columnar

Answer 10

It is in the GI tract and bile duct, contains microvilli to increase the surface area for absorption. Made of cytoskeleton proteins. Its roles our absorption (intestine) and sensation (taste buds, olfactory epithelium), protection and secretion.

Question 11

Simple squamous

Answer 11

Located in the capillaries, alveoli, abdominal and pleural cavities. Has roles in absorption, filtration and is a minimal barrier to diffusion. Very thin so small distance for diffusion

Question 12

Simple cuboidal

Answer 12

Located in the glandular epithelium (glands and ducts, kidney tubules, covering of ovaries). Roles in secretion as it covers glands

Question 13

Pseudostratified columnar

Answer 13

Located in the upper respiratory tract, trachea. Roles in absorption and protection, contains cilia

Question 14

Transitional epithelium

Answer 14

Stretchable layer of the bladder

Question 15

Nuclei stain

Answer 15

Haematoxylin (blue/purple)

Question 16

Cytoplasm stain

Answer 16

eosin (pink)

Question 17

Nerve cell stain

Answer 17

Golgi stain