Histology

Question 1

What are the two interacting components of tissues

Answer 1

Cells and Extracellular Matrix

Question 2

What is the proper sequence of tissue preparation?

Answer 2

I. Fixation
II. Dehydration
III. Clearing
IV. Infiltration(Impregnation)/Embedding
V. Trimming/Sectioning
VI. Staining
VII. Mounting & Labelling

Question 3

Give some histological stains and their reactions

Answer 3

Hematoxylin (basic) and Eosin (acidic)
- Blue: Nuclei
- Pale Pink: Cytoplasm

Periodic Acid Schiff (PAS)
- Red/Magenta: PAS-Positive substances
- Blue: Nuclei

Masson’s Trichrome
- Red: Muscle, RBC, Keratin
- Dark Blue: Nuclei
- Blue: Collagen and Mucus

Weigert’s Stain
- Dark blue: Elastic fibers

Wright Stain
- Purple/Blue: Nuclei
- Bluish Gray: Cytoplasm
- Red/Pink: RBC

Question 4

What are artifacts and what are its different types?

Answer 4

Artifacts are distortions that are not features of the living tissue caused by errors in techniques and procedure during slide preparations.

Types:
1. Minor Shrinkage (due to fixative, dehydration, or heat in embedding)
2. Wrinkles or Folds
3. Foreign Body artifact
4. Irregular distribution of stains
5. Sectioning artifacts (tears, scratches, etc.)

Question 5

What are the major kinds of microscopes?

Answer 5

Light Microscope and Electron Microscope

Question 6

What are the planes of section?

Answer 6

Longitudinal section, Transverse section, Tangential section, Oblique section

Question 7

A type of tissue that covers the surfaces of the body, lines cavities and organs, and forms glands. It serves protective, absorptive, secretory, and sensory functions.

Answer 7

Epithelial tissue

Question 8

A type of epithelium consisting of single layer of cells

Answer 8

Simple

Question 9

A single layer of flat cells that allows for diffusion and filtration. Found in air sacs of lungs, lining blood vessels, and serous membranes.

Answer 9

Simple Squamous Epithelium

Question 10

Multiple layers of flat cells. Outer layers are squamous, providing protection. Found in skin, oral cavity, esophagus, and vagina.

Answer 10

Stratified Squamous Epithelium

Question 11

Single layer of cube-shaped cells. Functions in secretion and absorption. Found in kidney tubules, thyroid follicles, and salivary glands.

Answer 11

Simple Cuboidal Epithelium

Question 12

Single layer of tall, rectangular cells. May have cilia or microvilli. Functions in absorption and secretion. Found in the digestive tract and uterine tubes.

Answer 12

Simple Columnar Epithelium

Question 13

Appears stratified but is actually a single layer of cells with varying heights. Often ciliated. Lines the respiratory tract and parts of the male reproductive system.

Answer 13

Pseudostratified Columnar Epithelium

Question 14

Stratified epithelium that can change shape to accommodate stretching. Found in the urinary bladder and parts of the ureters.

Answer 14

Transitional Epithelium

Question 15

Epithelial cells specialized for secretion. Can be exocrine (secrete onto surfaces through ducts) or endocrine (secrete hormones into the blood).

Answer 15

Glandular Epithelium

Question 16

What is the difference between Exocrine and Endocrine Glands?

Answer 16

Exocrine gland releases its secretions through ducts onto body surfaces or into body cavities. Examples include sweat glands, salivary glands, and mammary glands.

Endocrine gland releases hormones directly into the bloodstream. Examples include the thyroid gland, adrenal glands, and pituitary gland.

Question 17

Differentiate microvilli from cilia

Answer 17

Microvilli are tiny, finger-like projections on the apical surface of certain epithelial cells, increasing surface area for absorption. It is composed mainly of microfilaments. Common in the small intestine.

Cilia are hair-like projections on the surface of some epithelial cells that move in coordinated waves. Composed of microtubules. Found in the respiratory tract to move mucus and debris.

Question 18

Differentiate Serous Gland, Mucous glands, and Holocrine glands.

Answer 18

Serous - Exocrine glands that produce a watery, enzyme-rich secretion. Common in salivary and pancreatic glands.

Mucous - Exocrine glands that secrete a thick, viscous fluid rich in glycoproteins. Found in the respiratory and digestive tracts.

Holocrine - Glands that accumulate their secretions within the cell and then rupture, releasing the entire cell and its contents. Example: sebaceous (oil) glands

Question 19

Cell junctions that mechanically link adjacent cells, providing strength and preventing separation. Common in tissues subjected to mechanical stress.

Answer 19

Desmosomes

Question 20

Small channels connecting adjacent cells, allowing for direct cell-to-cell communication and passage of ions and small molecules.

Answer 20

Gap Junctions