OAP - Epithelium, Connective Tissue and Cell Junctions - Topic 2

Question 1

Define histology

Answer 1

• Histo = tissue
• Logos = study
The study of cells and tissues by
microscopy’

Question 2

Explain the general structure of

epithelial tissue

Answer 2

‘Layer or layers of cells that cover body
surfaces or line body cavities’
• Covering and lining external or internal body
surfaces
• Forms the secretory portion of glands

Question 3

Role of epithelium?

Answer 3

• Protection
• Absorption
• Secretion
• Filtration
• Excretion
• Sensory perception

Question 4

What are the layers in the epithelial tissue?

Answer 4

Simple
Stratified
Psuedostratified

Question 5

What are the different types of shapes of the epithelial cell?

Answer 5

Squamous
Cuboidal
Columnar
Transitional

Question 6

Describe the 3 layers in the epithelial tissue.

Answer 6

• Simple
- A single layer
• Stratified
-2 or more layers
• Pseudostratified
-A single layer, but looks like
multiple layers

Question 7

Describe the 4 different shapes of epithelial cells.

Answer 7

• Squamous
- Squashed, thin

• Cuboidal
-Same height and width all around (like a
square)

• Columnar
- much taller than they are wide

• Transitional
-change shape from cuboidal to squamous
and back, as tissues stretch and then
collapse (e.g. in the bladder)

Question 8

Adaptations can exist in certain epithelial cells

to help them function in a certain way, what are they?

Answer 8

• Microvilli
-Membrane projections that increase the surface
area of plasma membrane (for absorption)

• Cilia
-tiny hair like structures, that are motile and sweep
debris and mucus

• Keratin
-a protein that helps protect skin from heat,
microbes and chemicals

Question 9

What is connective tissue?

Answer 9

• Most abundant and widely
distributed tissue in the body
• The ‘space filling’ tissue

Question 10

What are the common structural

elements of connective tissue

Answer 10

Cells

Extracellular Matrix

Question 11

What are the Cell types found in connective

tissue?

Answer 11

• Fibroblasts

• Most abundant cell type
• Secrete fibres and ground substance

• Adipocytes

• White blood cells
-Involved in immunity

Question 12

What is the extracellular matrix made up of?

Answer 12

• Fibres

• Collagen fibres
• Elastic fibres
• Reticular fibres

• Ground substance
-Fluid or gel-like
-Binds everything together (fills the
space)
-The component of connective tissue
that lies between the cells and fibres

Question 13

What are dense and loose connective tissue?

Answer 13

Dense: Tissue packed together, organised, E.g. Aorta
Loose: Gaps, Not much Extracellular matrix to fill gaps, E.g. Elastic Structures

Question 14

Explain the difference between dense and loose connective tissue.

Answer 14

Dense: Packed better, More Collagen fibres
Loose: Less cells, Less Collagen Fibres

Question 15

List the different types of cell junctions

Answer 15

1. Tight junctions
2. Desmosomes
3. Gap junctions

Question 16

What is the structure of Tight Junctions?

Answer 16

• impermeable junction
• Forms continuous seals around the cells
• Formed by special integral membrane proteins

Question 17

What is the function of Tight Junction?

Answer 17

-Prevent molecules from passing between cells

Question 18

What is the structure of Desmosomes?

Answer 18

• Anchoring Junctions
• Bind adjacent cells to each other
• Formed by connecting linker proteins

Question 19

What is the function of Desmosomes?

Answer 19

Helps prevent cellular layers from tearing apart under mechanical stress

Question 20

What is the structure of Gap Junctions?

Answer 20

-Permeable
-Adjacent plasma membranes come into
close contact
-Channels (connexins) are made from integral proteins.

Question 21

What is the function of Gap Junctions?

Answer 21

• Allows adjacent cells to communicate with each other

- Allows passage of small ions from cell to cell