Introduction to Histology

Question 1

Name the four tissue types.

Answer 1

epithelium, connective tissue, muscle, and nerve

Question 2

epithelium

Answer 2

all cells are in close contact with each other

line all organs of the body, not just the surfaces but also the inside

every blood vessel is lined by epithelium that is only one cell layer thick

Question 3

connective tissue

Answer 3

defined by cells separated by some kind of intracellular matrix

tendon or ligament - bundles of collagen fibers, fibroblasts are squished flat inbetween collagen cables

loose or dense connective tissue - loose connective tissue is more cellular, whereas dense connective tissue is packed with collagen

Question 4

hematoxilyn and eosin stain (H&E)

Answer 4

hematoxilyn - basic die that stains acid such as DNA, RNA, etc.

eosin - acidic dye that stains basic structures like most proteins

this counterstain mix is the most commonly used

Question 5

Mallory’s connective tissue stain

Answer 5

collagen and reticular fibers tain blue, elastic fibers yellow or pink, nuclei, fibrin, and neuroglial fibrils red

Question 6

Masson’s trichrome method

Answer 6

nuclei stain dark blue, cytoplasm and neuroglial fibers red, and collagen green

Question 7

periodic acid-schiff method (PAS)

Answer 7

used to demonstrate structures rich in glycan polymers or oligomers, depends on the selective oxidation by periodic acid of cis 1,2,-glycols and 2,2-amino alcohols to aldehydes, stains aldehydes reddish purple

Question 8

phosphotungstic acid hematoxylin (PTAH)

Answer 8

ideal stain for the demonstration of astroglial fibers, which stain blue as do striated muscle fibers and mitochondria

collagen, reticular fibers and ground substance of bone and cartilage stain varying shades of yellow to brownish red, coarse elastic fibers stain purple, nuclei are blue

Question 9

wright’s stain

Answer 9

differential stain for blood cells, erythrocytes appear red or pink, nuclei deep blue or purple, basophilic granules deep purple, eosinophilic granules red to red-orange, neutrophilic granules reddish-brown to lilac, platelets violet to purple, and lymphocyte cytoplasm pale blue

Question 10

Verhoeff stain

Answer 10

good stain for connective tissue, collagen stains bright red, muscle and cytoplasm yellow, nuclei blue, and elastin a dark brown-black