Principles of Histology II

Question 1

Define cell differentiation

Answer 1

Process of a change a cell undergoes to achieve its mature functional form

Question 2

Outline the three ways cells can be classified.

Answer 2

• FUNCTIONAL
• SHAPE/SIZE
• ORGANISATION

Question 3

How can functional cells be further classified?

Answer 3

• Cells that move
• Cells that communicate
• Cells that form barriers
• Cells that secrete

Question 4

Give three examples of motile cells

Answer 4

• Sperm
• Macrophages - move towards pathogens
• Muscle cells

Question 5

What are barrier cells, with an example?

Answer 5

• Cells that form barrier between structures or environments
• EXAMPLE: epithelial cells
• Will often have features such as cilia

Question 6

Give examples of secretory cells and how they can be distinguished

Answer 6

• Goblet cells in respiratory epithelium
• Distinguished based on how and what they secrete, based on their location

Question 7

Give examples of communication cells

Answer 7

NEURONS - communication betwen receptors and the CNS

Question 8

What are cell tissues?

Answer 8

• Collection of cells and the extracellular material surrounding cells

Question 9

What are the four types of tissue?

Answer 9

• Epithelium
• Muscle tissue
• Nervous tissue
• Connective tissue

Question 10

Describe the general structure of the epithelium.

Answer 10

• Composed mostly of cells with minimal extracellular material between cells
• Non-vascular - nutrients reach cells by diffusion through basal lamina

Question 11

How can epithelial cells be classified?

Answer 11

• Number of layers: Simple (1 layer), Stratified (2 layers or more), Pseudostratified (single but looks stratified)
• Cell shape: Squamous, cuboidal, columnar, transitional

Question 12

What is the purpose of the epithelium?

Answer 12

• Protect underlying structures
• Act as a barrier
• Secrete and absorb substances
• Permit passage e.g of O2 into bloodstream for respiratory epithelium

Question 13

Define connective tissue

Answer 13

• Supports other cells
• Synthesise and secrete extracellular matrix

Question 14

What do the following cell type endings tell you about the cell?
- blast
- cyte
- clast

Answer 14

BLAST - Tissue forming cells
CYTE - Maintenance cells
CLAST - Tissue absorbing cells

Question 15

What are three components of extracellular matrix?

Answer 15

• FLUID - lost during processing of slides
• Ground substance - gel-like material that contains cells
• Protein fibres

Question 16

What are the three types of protein fibres in the extracellular matrix?

Answer 16

• COLLAGEN - Secreted by fibroblasts, flexible but inelastic, TYPE 1 - found in tendons, ligaments, skin and bone, TYPE 2 - found in cartilage
• RETICULAR - made up of Type 3 collagen fibres, thin and short
• ELASTIC - formed from elastin, makes tissue elastic

Question 17

Give some types of connective tissue.

Answer 17

• Loose
• Dense - can be regular or irregular
• Specialised
• Embryonic

Question 18

What are three types of muscle tissue?

Answer 18

SKELETAL
CARDIAC
SMOOTH

Question 19

What are glands?

Answer 19

• Secretory structures that develop from infolding or outfolding of epithelium in the embryo

Question 20

What are the two types of glands and how can they be distinguished?

Answer 20

• Exocrine glands - secrete substances into a ductal system
• Endocrine glands - secrete substances directly into the bloodstream

Question 21

Describe plasma.

Answer 21

• Plasma - 90% water and 10% proteins/ions
• Platelets - anuclear cells involved in clotting
• WBCs - granulocytes (cells ending in -phil), agranulocytes (cells ending iin -cyte)
• RBCs - 7 micrometers in diameter