Lecture 1 Flashcards
What two chemical solvents that can be used to remove alcohol from a specimen?
Xylene and limonene
In what four locations are neurons found?
- Brain 2. Spinal Cord 3. Nerves 4. Ganglia
How does smoking change the epithelial layer and surface modification of a trachea?
The epithelial layer transforms from being pseudostratified to stratified. The surface is modified from being ciliated to non-ciliated epithelium
What are the two standard reference stains? What part of the cell is colored by each stain?
Hematoxylin and Eosin. Hematoxylin stains the Nuclei blue/purple; Eosin stains the cytoplasm and connective tissues pink/orange, and RBC bright red. Mnemonic: Henry (boy so blue/purple) loves Nancy (nuclei); Emily (girl so pink/orange) loves Chris (cytoplasm) and Christina (connective tissue)
What are the four primary tissue classes?
Epithelial, Connective, Muscle, Nervous Mnemonic: Everyone Can Make Nachos (Credit: Rafael Brandao)
What does embedding mean in histotechnology?
Suspending specimens in molds filled with liquid wax. Once the wax cools and solidifies the “embedded” specimens are removed from the molds and used for sectioning, the next step in histotechnology
What glue is used to protect and preserve stained specimens during coverslipping?
Epoxy
What are the seven (7) steps of histotechnology?
- Grossing; Fixation 2. Processing 3. Embedding 4. Sectioning 5. Staining 6. Coverslipping 7. Diagnosis Mnemonic: George Fixed Patricia’s Engine So She Could Drive (Credit: Ben Baranes)
What color is a raw image from an electron microscope (EM)?
Grayscale
What type of blade is used to section specimens in an ultramicrotome?
A diamond blade
How is a cross-section related to a longitudinal section?
A cross-section is perpendicular to the longitudinal section.
What is the main difference between Histologists and Pathologists?
Histologists do not Diagnose
In microscopy, what is visible light focused with? What are electrons focused with?
Glass lenses focus visible light. Magnets focus electrons
What is the usual thickness of a section cut with a microtome?
4 to 5 microns (.004 mm to .005 mm)
What are connective tissue cells suspended in?
Extracellular matrix (very abundantly, more matrix than cells)
What is metaplasia?
Normal or abnormal change in tissue
What characteristics of the extracellular matrix help to distinguish the four(4) tissue classes?
- Proportion of water 2. Types of fibrous protein 3. Composition of ground substance
What metal is used to stain sections for use in an electron microscope?
Lead
What is the ground substance in the extra cellular matrix (ECM)?
Material between cells other than water and fibrous proteins
What are the three surface modifications found on epithelial tissues?
- Cilia 2. Microvilli 3. Keratinization
What is an example of a specialized connective tissue?
Adipose tissue, hematopoietic tissue
What is the extracellular matrix?
Material between cells such as water, fibrous proteins and ground substance.
After sections are picked up on a microscope slide, what chemical solvent is used to remove the wax ribbon from the specimen?
Xylene
In what direction does the tracheal cilia sweep mucus?
Healthy tracheal cilia sweeps mucus up the trachea. Mucus sliding down the trachea could cause wheezing and coughing
Why are fixed specimens moved through a graded series of alcohols?
To remove water
Which type of nerve tissue cell is more abundant?
Glial cells
What are the four (4) different shapes of Epithelial tissue?
- Squamous 2. Cuboidal 3. Columnar 4. Transitional
Which one of the four tissue types has the most ECM? Which one the least?
Connective tissue has the most. Epithelial the least
How does electron beam wavelength affect image resolution?
Shorter wavelength produces higher resolution images
What tool/machine is utilized to perform sectioning of specimens to be viewed under a light microscope?
The microtome
Electrons shoot _________ a specimen in a Transmission EM, while in a Scanning EM the electrons _______ off of the specimen.
thru; bounce
Approximately how many different cells types are in the body?
200
What are specimens embedded in for sectioning with an ultramicrotome?
Epoxy and/or other hard plastics
What are two examples of supporting connective tissue?
Cartilage, Bone
How do neurons receive, integrate, store and transmit information?
By releasing neurotransmitter chemicals from the tips of axons to be received by receptors on other cells
What is the initial step of gross processing (grossing)?
Cutting fresh specimens into small pieces to facilitate penetration of fixatives
How thick are sections when used in electron microscopes?
.01 micron or less
What does a continuously cut section resemble?
A ribbon
What is differentiation?
Unspecialized tissues, as in an embryo, change into specialized mature tissues
What is the difference between Hypertrophy and Hyperplasia?
Hypertrophy is the increase in size of cells. Hyperplasia is the increase in the number of cells
What is the average thickness of a Red Blood Cell? Average cell in the human body?
RBC is around 8 microns; Average cell is 60 to 100 microns
Which of the three muscle types is/are striated?
Skeletal and Cardiac. Smooth muscle is not striated
What are the two types of Nerve Tissue cells?
Neurons and glial cells
What is the major function of muscles?
To exert physical force
How does the layer of cells help to distinguish simple epithelial tissue from stratified epithelial tissue?
One layer of cells is simple epithelial tissue Two or more layers of cells is stratified epithelial tissue
What are the four types of connective tissues?
- Embryonic CT 2. CT Proper 3. Specialized CT 4. Supporting CT
What is neoplasia?
Growth of abnormal tissue (hyperplasia) into a tumor. Can be both benign and malignant
Why is a section of specimen transferred to float in a warm water bath?
To smooth out wrinkles
What is the advantage of epithelial cells having microvilli?
Increased surface area
How do muscles respond to stimuli?
By contracting
What can xylene and/or limonene solvents be replaced with?
Mixtures of heated paraffin and other waxes
Why are aldehydes used to preserve a specimen?
Aldehydes (gluteraldehyde or formaldehyde) react with nitrogen in proteins to form stable bridges between adjacent proteins. These bridges stiffen a specimen for easier cutting.
