Epithelial cells

Question 1

What are haemopoietic cells?

Answer 1

Blood cells, tissue-resident immune cells, and cells derived from bone marrow.

Question 2

What are neural cells?

Answer 2

Cells that constitute the nervous system: Neurones (transmit electrical signals), and glial cells (provides neurone support and insulation - Schwann cell).

Question 3

What are contractile tissues?

Answer 3

Skeletal muscle, cardiac muscle, smooth muscle.- Tissue with the ability to contract.

Question 4

What are connective tissue cells?

Answer 4

Fibroblasts (many tissues), chondrocytes (cartilage), osteocytes (bones)- Connects, bind and supports tissue cells.

Question 5

What are epithelial cells?

Answer 5

Cells forming continuous layers, layers line surfaces and separate tissues compartments- variety of alternative function- Secretion, selective absorption, protection, transcellular transport and sensing.

Question 6

What are squamous epithelial cells?

Answer 6

Flattened, plate shape, abundant cytoplasm and small round circular nucleus.

Question 7

What are columnar cells?

Answer 7

Arranged in columns; approximately 3000 microvilli per cell (maximises surface area for absorption). Simple columnar epithelial cells secrete molecules- enterocytes assist in molecular degradation in gut.

Question 8

What are cuboidal cells?

Answer 8

Cuboidal: Cube-like (lines nephrons, ovaries and ducts)- main function is secretion.

Question 9

What are stratified epithelium?

Answer 9

Multiple layers of cells

Question 10

What are pseudo-stratified epithelium?

Answer 10

T​his epithelium appears to be multi-layered, but on close examination, the surface cells havecontactwith the basal lamina. e.g. airway (trachea and bronchi) epithelium, various ducts in the urinary and reproductive tracts.

Question 11

What is epithelial cell polarity?

Answer 11

Different regions of the cell surface being different with discretely organised cellular contents. The discrete domains (formed by junctions) causes membrane polarity.

Question 12

What is a lateral membrane?

Answer 12

Membrane is situated between two surfaces, membranes of adjacent membrane oppose each other

Question 13

Why is polarity important?

Answer 13

Important for secretion of fluid, and solute transport

Directional flow and ion/cotransporter proteins

Question 14

What are tight junctions?

Answer 14

Belt around apical lateral membrane (membranes of two adjacent cells accumulate together to form a barrier). Binding action prevents molecules from passing in between the cells.

Question 15

What are adherens junctions?

Answer 15

Controls formation of other junctions. Junction holds adjacent epithelial cells together.

Question 16

What are desmosomes?

Answer 16

Cell-cell anchoring junctions- provide mechanical stability as a result of strong cellular adhesives.

Question 17

What are gap-junctions?

Answer 17

Allows various molecules and ions to pass between cells. Composed of two aligned connexons. Gap junctions allow for electrical communication between cells, and passage of second messengers.

Question 18

What is exocrine secretion?

Answer 18

Exocrine secretion is the secretion of molecules within the duct or lumen

Question 19

What is endocrine secretion?

Answer 19

Secretion directly into the blood

Question 20

Which membrane do exocrine cells release secretions through?

Answer 20

Apical membrane

Question 21

Which membrane do endocrine cells releases secretions into?

Answer 21

Basal membrane

Question 22

What is constitutive secretion?

Answer 22

Secretory vesicles as they formed move directly to the plasma membrane, releasing their contents immediately

Question 23

What is stimulated secretion?

Answer 23

Stored in cytoplasm within secretory vesicles, fusing with membrane upon stimulation

Question 24

Which cells are produced within the small intestine?

Answer 24

Stem cells are present within the crypt of Lieberkuhn , replacing cells lost from the villus tip

Question 25

How does hyperproliferation occur?

Answer 25

Cell production > cell loss, cells accumulate into a thick layer known as corns

Question 26

What conditions cause hyper proliferation?

Answer 26

Frequent abrasions and pressure

Question 27

Which virus causes hyper proliferation?

Answer 27

The papilloma virus, controls stratified squamous epithelium