Intro to histology

Question 1

Outline the steps involved in tissue preparation

Answer 1

1)Fixation (preserving tissue) eg. Formalin (light) or glutaraldehyde (electron)
2)Dehydration (removing water with alcohol) and clearing (removing alcohol)
3)Embedding in a suitable medium such as paraffin
4)Sectioning into thin slices
5)Mounting on glass slides for ease of handling
6)Staining with various dyes so cells and tissues can be differentiated from each other

Question 2

Haematoxylin

Answer 2

base that binds to acidic components such as DNA staining them purple, these elements are basophilic

Question 3

Eosin

Answer 3

acid that binds to cytoplasmic constituents that have a basic pH staining them pink, these elements are acidophilic

Question 4

Masson’s trichrome

Answer 4

stains nuclei dark blue, stains muscle and cytoplasm red, stains collagen green

Question 5

Epithelial tissue- derived from where and what is the function?

Answer 5

Derived mainly from ectoderm but other embryonic layers too, covers surfaces, lines body cavities, or form solid glands such as salivary glands

Function-
Protection of underlying tissues
Transcellular transport
Secretion of mucous, hormones and enzymes from glands
Absorption of material from lumen
Selective permeability to control movement

Question 6

Muscular tissue- derived from where and what is the function?

Answer 6

Derived from ectoderm
posses contractile properties, muscles allow a person to move, speak and chew

Question 7

Nervous tissue- derived from where and what is the function?

Answer 7

Derived from ectoderm
responsible for coordinating and controlling many body activities, it receives stimuli and sends signals to the brain and spinal cord

Question 8

Connective tissue- derived from where and what is the function?

Answer 8

Derived from mesoderm, such as cartilage and bone
supports and protects and gloves structure to other tissues and organs in the body

Question 9

Simple epithelium

Answer 9

Consisting of only 1 layer of cells:
Squamous
Cuboidal
Columnar

Question 10

Stratified epithelium

Answer 10

Composed of 2 or more cell layers:
Squamous keratinised or non-keratinised
Cuboidal
Columnar

Question 11

Basement membrane

Answer 11

separates epithelia from underlying connective tissue, a thin acellular layer which provides support and attachment for the epithelial cells and acts as a selective diffusion barrier. Composed of a basal lamina and a reticular lamina. Basal lamina is secreted by the epithelial cells and consists of lamina lucida and lamina densa

Question 12

Tight junction

Answer 12

Prevents proteins passing through

Question 13

Adherens junction

Answer 13

Tightly binds cells together

Question 14

Desmosome

Answer 14

Additional strengthening of bonds

Question 15

Gap junction

Answer 15

Allow molecule movement

Question 16

Hemidesmosome

Answer 16

Bound to basal membrane