Lecture 1 - Histology Principles and Techniques Flashcards
Four Basic Tissue Types
Epithelial
Connective
Muscle
Nervous
Epithelial Tissue
Either a sheet of cells lining inner or outer surface of an organ
Or it can form glands
Connective Tissue
Connects to two tissue types
different functions by location
Ratio of cell and extracellular matrix is based on function of the tissue
Muscle Cells
Specialized for contractility
Nervous Tissue
Specialized for transmission of signals
Light Microscopy
Looking at a piece of tissue through a microscope. Low resolution
Must apply a stain for color
Electron Microscopy (TEM)
Very thin tissue samples
Shine a beam of light of electrons is passed through the tissue and absorbed on photographic plate. Higher Resolution
Scanning Electron Micrograph
Used to look at the surface of something. Uses same process of using electrons
Finger Like Projections
Microvilli
Histology Preparation Methods - and what they do
Smear - is a swipe of cells and smeared across the slide. Stained then examined
Sectional Method- prepare a thin slice of tissue for investigation
Steps involved in Sectional Microscope Preparation
Fixation - stabilized so it wont deteriorate from being dead. (Ex. formalin, Bouin’s, gluteraldehyde)
Embedding - embed in rigid media (wax plastic or gel)
Sectioning - Deli cut a slice off
Mounting- adhere to the glass slide
Staining - give contrast to some elements
How Large is a RBC
7.5microns
so you can use this as a ruler for other things around the body
Plane of Section (3 types)
The way you slice the sample.
Oblique - anything cut off of the vertical
Coronal/longitudinal/sagittal - is a vertical cut
Transverse - is a horizontal cross section
The Three Types of Stains
Acid base
Specialized Stains
Metallic Stains - for structural elements
Hematoxylin
Stains Acidic Parts Dark Purple
So it is a basic stain
DNA Acidic
Eosin
Is a acidic stain that will stain basic things. stains things pink or orange
ex// cytoplasm, histones, RBC (hemoglobin)
Basophilic
Refers to cell or tissue components that have affinity for basic stains
Acidophilic or Eosinophilic
Refers to cell or tissue components that have affinity for acidic stain
Hematoxylin and Eosin Stain (HandE)
Used to stain Acid and basic components. Good to look at morphology
PAS - Periodic Acid-Schiff Stain
Used to demonstrate structure rich in carbohydrates
Carbohydrate = pink or magenta
ex// microvilli
Trichrome Stain
Specialized Stain to Asses extracellular matrix
differentiates fibrous components
collagen, mucin = blue
Elastic Stain
Looks at the connective tissue element elastin
Elastic Fibers appear black or brown
Silver Stain
Used to demonstrate structural fibers
Reticular Fibers Stain Black
Myelin Stain
Stains the fatty sheath over the nerve axons
Immunohistochemistry
Takes advantage of antibodies association to antigen.
So we are labeling a specific portion of the cell
