Lab: Tissues and Layers

Question 1

How many types of tissues are there in the human body? What are they?

Answer 1

Everything in the body is one of four types of tissue: epithelium (sheets of attached cells), connective tissue (including bone, cartilage and blood), muscle (smooth, skeletal and cardiac), and nervous tissue.

Muscle and nervous tissue always occur within (surrounded by) connective tissue.

Question 2

What are the general layer names?

Answer 2

Mucosa, submucosa, muscularis, serosa/adventitia

Question 3

What are the sublayers of the mucosa layer in the GI system?

Answer 3

epithelium, lamina propria, muscularis mucosae

Question 4

What are the sublayers of the muscularis layer?

Answer 4

inner circular layer and outer longitudinal layer

Question 5

What are the names of layers in blood vessels?

Answer 5

mucosa- tunica intima
muscularis- tunica media
adventitia- tunica adventitia

Question 6

Euchromatin

Answer 6

relatively uncoiled (usually during transcription) it is relatively lightly staining

Question 7

Heterochromatin

Answer 7

Tightly packed, and therefore dense staining chromatin

Question 8

Why is the nuclear membrane usually visible while the cell membrane is usually not visible?

Answer 8

Heterochromatin tends to be concentrated along the nuclear membrane, giving it a distinct purple outline that allows you to see the the nucleus clearly in just about every nucleated cell.

Question 9

hematoxylin and eosin (H&E) dyes

Answer 9

Anything with a net negative charge in the tissue section will stain with hematoxylin and is said to be basophilic. Anything with a net positive charge will stain with eosin and is termed acidophilic or eosinophilic. Thus, the H&E stain reflects, to a first approximation, the acid/base properties of the material.

Ex:
-DNA/RNA, ribosomes, and RER will stain purple
-mitochondria, proteins, cytoplasm, and collagen will stain red/pink

Question 10

periodic acid-Schiff (PAS) stain

Answer 10

stains for glycoproteins (most importantly, mucins and a cell’s glycocalyx).

Question 11

artefacts

Answer 11

things that appear in the section as a result of the preparation technique that do not indicate anything about the in vivo state of the specimen

ex: cut surfaces, differential shrinkage of tissue, incomplete perfusion, folds, tears, dust, etc.

Question 12

What is a layer?

Answer 12

A layer is a region of predominately one type of tissue, oriented parallel to the lumenal surface at varying depths

Question 13

What is mesothelium?

Answer 13

The simple epithelium of the serosa of the GI system