Epithelial Cells 1

Question 1

Nucleolus Function

Answer 1

Site of rRNA synthesis

Question 2

Nuclear Envelope Function

Answer 2

Is continuous with the ER and is involved in packaging and processing proteins

Question 3

What is the nuclear lamina?

Answer 3

Specialized type of cytoskeleton formed on the internal surface of the nuclear envelope. Involved in assembly and disassembly of envelope during cell division.

Question 4

SER function

Answer 4

It is more tubular and lacks ribosomes. Main function is lipid metabolism (steroid synthesis). It is also a site of storage of Ca2+

Question 5

Golgi Function

Answer 5

Modifying, sorting, and packaging macromolecules. Made of cis, medial and trans with trans facing periphery.

Question 6

Peroxisomes function

Answer 6

Contain enzymes for lipid and oxygen metabolism e.g. catalases and peroxidases (toxic).

Question 7

Cytokseleton Filament Types

Answer 7

• microtubules
• intermediate filaments
• microfilaments

Question 8

Microtubules Info and Function

Answer 8

• Polymers of alpha and beta tubulin
• Approximately 20nm diameter
• Involved in cell shape and acts as tracks for the movement of organelles and cytoplasmic components within the cell.
  Motor proteins are needed for this movement.
• major component of cilia and flagella.
• form part of spindle fibres

Question 9

Intermediate filament info

Answer 9

• `10-15nm diameter
• give mechanical strength to cells
• desmosomes are connected via IFs
• Different cell types have different IFs.
  Nuclear Lamins are intermediate filaments which form a network on the internal surface of the nuclear envelope.

Question 10

Microfilament Info and Fucntion

Answer 10

• polymers of actin associate with adhesion belts in epithelia and with other plasma membrane proteins.
• involved in cell shape and movement
• usually bundles near the cell periphery
• has a helical structure

Question 11

Main Cell Types

Answer 11

• epithelial cells
• mesenchymal cells
• haematopoietic cells
• neural cells (neurones of clial cells)

Question 12

Tissue definition

Answer 12

a group of cells whose type, organisation and architecture and integral to its function
- Tissue = Cells + Extracellular Matric + FLuid

Question 13

Extracellular Matrix Definition

Answer 13

The insoluble material that yo will find extracellularly (collagen, elastn, proteoglycan)

Question 14

Junction Types

Answer 14

• Tight Juncton
• Adhesion Belts
• Desmosome
• Gap Junction

Question 15

Tight Junction Info

Answer 15

• zonula occludens (belt)
• more elaborate the network, the tighter the seal
• these junctions seal the paracellular pathways as well as segregate the membranes of different cells to stop the proteins which diffuse through.
• Has ‘kiss’ points

Question 16

Adhesion Belt Info

Answer 16

• zonula adherens
• formed just basal to the apical tight junction
• Cadherins bind to similar molecules on the adjacent cell and cluster to form these junctions. Actin cytoskeleton is closely associated.
• other junctions form after this one has. Therefore it is the master junction

Question 17

Desmosome Info

Answer 17

• Macular Adherens
• Cadherins bind membranes from the cytoplasmic plaque while keratin filaments anchor this
• doted around the lateral membranes of cells.
• very abundant in the epidermis

Question 18

Gap Junction

Answer 18

• macula communicans
• made of cluster of pores which are formed by membrane proteins.
• allow the passage of ions and small molecules between the cells. .- can be opened and close by electrical activity and calcium concentration `