Histology Flashcards
Histology
study of healthy tissue
Pathology
study of unhealthy tissue
What are major components of a tissue?
cells, fibres, and matrix
What are the four different types of tissues?
epithelial, connective, muscle and nervous tissue
Epithelial tissue
tissue that covers and lines organ and organisms; found on the surface
Connective tissue
tissue that connects and supports; not found on the surface
Muscle tissue
tissue that contracts and produces movement
Nervous tissue
tissue that responds to stimuli and conducts impulses for communication of information
Three ways to classify epithelia cells
number of cell layers, shape of cells, and function of cells
Two categories based on number of cell layers
simple epithelia + stratified epithelia
Simple epithelia
comprised of a single layer of cells
Stratified epithelia
comprised of two or more layers of cells
Three categories based on shape of cells
squamous epithelia + cuboidal epithelia + columnar epithelia
Squamous epithelia
flat shape
Cuboidal epithelia
cubed shape
Columnar epithelia
elongated shape
Two categories based on function of cells
transitional epithelia + germinal epithelia
Transitional epithelia
specialized to deal with stretch and serves as a barrier for toxicity
Germinal epithelia
lines the reproductive organs and specialized to produce gametes
Three types of fibres found in connective tissue
collagen + reticular fibres + elastin
Five types of cells found in connective tissue
fibroblasts + macrophages + mast cells + adipose cells + blood cells
Fibroblasts
synthesize fibres and matrix
Macrophages
ingest bacteria and dead cells
Mast cells
secrete heparin and histamine
Adipose cells
store fat and act as packing material
Three categories of connective tissue
loose, dense, and specialized
Loose
more ground substance, less fibres
Dense
less ground substance, more fibres
Specialized
provide structure, strength and support tissue
Three types of loose connective tissue
areolar, adipose, and reticular
Two types of dense connective tissue
irregular and regular
Three types of specialized connective tissue
cartilage, bone, and blood
Three categories of fibres in cartilage
hyaline, elastic, and fibrous
Areolar Fibres
- fibres are so far apart that they have room for the matrix in between
- strong enough to bind tissue, and soft enough to provide flexibility and cushioning
- cells obtain nutrients and expel waste here
- holds organs in place and attaches epithelial tissues to other underlying tissues
- found in gastrointestinal tract and blood vessels
Reticular Fibres
- main structural part of tissues
- forms a soft framework, and acts as a scaffold for cells
- found in lymphatic tissue and bone marrow
Adipose Fibres
- consists of adipocytes
- stores energy in the form of fat
- cushions and insulates the body
- found in subcutaneous tissue, mesentery, and bone marrow
Irregular Dense Connective tissue
- loose arrangement of fibres
- moderately viscous fluid matrix
- impact resistant, provides mechanical support
- found in joint capsules, muscles, and dermis of the skin
Regular Dense Connective Tissue
- fibres form main element and are composed of collagen
- rows of fibroblasts that generate fibres
- found in tendons and ligaments
Function of the Integument
- protects the body from mechanical injury & loss of fluid
- excretes waste and acts as a barrier against toxins
Structure of Integument
- epidermis and dermis
Intrinsic Aging Factors
genetics, hormones
Extrinsic Aging Factors
UV rays, diet, pollution, stress
How is tissue processed?
Fixation -> Paraffin Processing and Embedding -> Tissue sectioning -> Tissue staining -> Image analysis -> data & stats analysis
What were the tissue samples observed in the histology lab?
Mouse’s lungs, intestine, liver and appendix
What were the two stains used to stain the tissue? What colour did they turn?
Hematoxylin which stained DNA blue, and eosin which stained the rest of the cell components pink.
What is xylene used for?
To remove the paraffin/dissolve the wax from the slide
What is fixation?
Process in which cell structure is preserved
What is paraffin processing and embedding used for?
method used to study sections of tissues
What portions of the paraffin method did we perform in the histology lab?
embedding in paraffin, cleaning & staining, and preparation of permanent mounts
What reagent is used for the dehydration process of the paraffin method?
isopropyl alcohol (IPA)
What mounting medium was used in the histology lab?
Permount
What tissues will be used in the histology lab?
mouse skin, rat skin
What cutting apparatus is used for tissue sectioning in the paraffin method?
Microtome
