WK 2 - Histology

Question 1

Which stain is used the most?

Answer 1

Haematoxylin and Eosin stains.
Haematoxylin - affinity for blue nucleus
Eosin - stains proteins pink

Question 2

What are the four basic tissue types?

Answer 2

• Epithelium
• Connective tissue
• Muscle
• Nervous tissue

Question 3

Organs contain more than one tissue type. True or False?

Answer 3

True.

Question 4

What are the three embryological layers?

Answer 4

Ecto, endo and mesoderm.

Question 5

Which layer derives epithelium?

Answer 5

Epithelium can be derived from any one of the three germ layers.

Question 6

What does ectoderm layers form?

Answer 6

They form skin and associated glands and line oral, nasal and anal passages.

Question 7

What does the mesoderm layer form?

Answer 7

Epithelial lining of cardiovascular system and lining in thoracic and abdominal cavities along with tubules, ducts and accessory glands of urogenital systems.

Question 8

What does the endoderm layer form?

Answer 8

Epithelia of the gut, respiratory, urinary, liver, gall bladder and pancreas.

Question 9

How are the epithelium types classified?

Answer 9

If they are a single layer - simple or pseudostratified or if they are multi layer - stratified or transitional.

Question 10

What are the epithelial cell types?

Answer 10

• Squamous
• Cuboidal
• Columnar

Question 11

What are simple squamous epithelium properties?

Answer 11

• Flattened surface cell shape
• Function as frictionless surface and have selective gaseous and fluid exchange
• Located in blood and lymphatic vessels as well as alveolar, pleural and peritoneal cavities.

Question 12

What are simple cuboidal properties?

Answer 12

• Shaped like cube
• Function in secretions, absorption, act as conduit and protection
• Located in renal tubules and ducts and ovarian surfaces

Question 13

What are simple columnar properties?

Answer 13

• Arranged in columns and generally same height and nuclei on the same level
• They function for absorption, secretion, protection and transportation.
• They line the GIT, exocrine glands, uterine tubes and endometrium.
• Elongated nucleus and ‘holes’ are goblet cells which secrete mucous

Question 14

What are pseudostratified columnar properties?

Answer 14

• Appears multi layered and has an attachment to basement membrane and nuclei appear at different levels.
• They function for protection and movement of substances.
• Located in cell lining in upper respiratory tract and excretory passage and in male reproduction tract. Mostly in trachea and large bronchi.

Question 15

What are stratified squamous properties?

Answer 15

• Can be both keratinised or non-keratinised.
• They function to provide resistance to wear and tear and form physiological barrier.
• Located in skin, oral cavity, oesophagus and vaginal lining.

Question 16

Transitional epithelium properties?

Answer 16

• Multilayered and allows tissues to stretch. When relaxed they are several cell layers but when stretched they are only 2 or 3 layer thick.
• They function for protection and are capable of distension
• Located in cell lining, uterus, bladder and portion of ureter.

Question 17

What are cell surface specialisation?

Answer 17

Surface specialisation offers a range of function for tissues.

Question 18

What are the functions of keratin, microvilli, cilia and goblet cells?

Answer 18

Keratin - used as water proof barrier and protects underlying tissue cells.
Microvilli - mainly for absorption and increase SA. They also protect surface of the cells
Cilia - move substances over the cell surfaces and are located in upper respiratory tract.
Goblet cells - secrete mucosa and are found mainly in respiratory and GIT.

Question 19

What are the functions of cell to cell adhesion?

Answer 19

• Join together and external structures
• There junctions = tight, adherence, desmosomes, communication junctions and hemidesmosomes. Communicating junctions allow for communication and movement of certain molecules and ions between cells. Hemidesmosomes assist in joining the cell to basement membrane.

Question 20

What are the types of adherence junctions and functions?

Answer 20

• Adherence junction = Zonula adherens
  They provide attachment to strip of contractile filaments rich in actin and enable cells to change shapes.
• Desmosomes = Macula adherens
  Intracellularly and attaches to cytoskeleton elements and extracellularly adhesion proteins attached which enables cell-cell adhesion.