Cell Histology Week 1 Flashcards
What is histology?
Study of tissues in the body and how these tissues are arranged to make organs
What are the 4 basic tissues and what are their functions?
Epithelia- Barrier/ line surfaces
Connective- Packing, supporting and connecting
Muscle- Contractility
Nerve - Irritability and conduction
Unaided eye vs Microscope
What is the smallest an object can be for the human eye to detect?
How much does the light microscope improve vision?
The human eye cannot detect objects smaller than 0.2 mm or 200 micrometers.
The light microscope enhances object visibility by 1000x
What are the steps for tissue preparation for Microscopy?
- Fixation
- Dehydration
3.Embedding
4.Sectioning - Removal of paraffin
- Rehydration
7.Staining
8.Mounting on glass slide - Viewing Tissue
Fixation is when _______ are placed in _____ that preserve by _______ and ________.
small tissue samples are placed in a solution of chemicals that preserve by cross linking proteins and eliminating degrading enzymes
Dehydration is when _______ is used to ___________ from _________
Alcohol is used to remove all water from the tissue sample
Embedding occurs when the _________ tissue sample is placed in _________ and allowed to ________.
Paraffin-infiltrated tissue sample is placed in melted paraffin and allowed to harden
Trimming/Sectioning of the ___________ is done to expose the _____________ for _______ on the _______.
Paraffin block, tissue sample for sectioning on the microtome
Describe a longitudinal section
Through the length of the sample, similar to sagittal (will appear as a line)
Describe a cross section
Through the width of the sample, similar to transverse; think tree trunks (will appear as a circle for cylindrical objects)
Describe an oblique section
Angled cuts of the sample that are diagonal (Will appear as an oval for cylindrical objects)
Why is staining required?
Staining is done because most extracellular material and cells are colorless.
Most dyes behave like _____ and ______. They form _________ with _________ in ________.
Most dyes behave like acids and bases. They form salt linkages with molecules in tissue
What are the basic dyes?
Toluidine blue, methylene blue, Hematoxylin
What are the acidic dyes?
Eosin , fuchsin
Basic dyes react with __________ molecules which can also be called _______. Are these molecules ionic (+) or anionic(-)
Acidic molecules, basophilic, anionic
Acidic dyes react with ________ molecules which can also be called ___________.Are these molecules ionic (+) or anionic(-)
Basic molecules, acidophilic, ionic
In H&E staining, hematoxylin will stain basic molecules in the mitochondria or acidic molecules in the nucleus?
Hematoxylin is a basic dye. It attracts acidic molecules in the nucleus. Basic dyes prefer anionic molecules
the negatively charged phosphate backbones of DNA within the chromatin, which bind to the positively charged hematoxylin dye complex, causing the nucleus to stain blue.
In H&E staining, which dye will stain the basic molecules in the mitochondria?
Eosin! Mitochondria has basic molecules which are also ioninc. Eosin is an acidic dye that attracts basic molecules such as mitochondria.
What color will the cytoplasm show up as on an H&E stain?
The cytoplasm will be pink meaning that it is stained by eosin. Eosin is an acidic dye that attracts basic molecules indicating that the cytoplasm is acidophilic.
Luxol Blue and Hematoxylin stains which tissue best?
Nerve Cells
Trichrome staining displays results of ____________ staining as well as __________ which appears ________.
H&E Staining, connective tissue , greenish blue
Which staining is best for connective tissue?
Trichrome Staining
Heavy metal staining is best for __________
Showing the cell body and nucelus.
Golgi Stain involves _____ and _________. It is best for visualizing the __________.
Potassium dichomate and silver nitrate, dendrite pattern
Gold, Luxol Blue and Cresyl Violet are best for showing _________.
Nerve cell structure from the cell body, to the nucleus and the dendrites.
Cells with a lot of ________ and _______ cannot participate in H&E staining because ______.
What color will they appear in an H&E stain?
Cells with lots of fat and mucus cannot participate in H&E staining because they will be washed away during the dehydration step involving alcohol when preparing the sample.
White
Sudan black can be used to stain _______ and _______ but NOT ___________.
Lipid and myelin but NOT mucus
What stain is used for mucus?
PAS or Periodic Acid Schiff Reaction
Immunostaining involves using an __________ which is a ________ and using _________ with_______ to tag the cell.
Antigen which is a body marker and using the correlated antibody with flurorphore to tag the cell
PAS reaction is good for ________________.
Mucus, microvilli , basement membrane, glycogen granules.
Shrinkage of a sample can result because of _________________.
Fixation, Dehydration and Embedding
Shrinkage of a sample, wrinkles in tissue, residual stain can result to the presence of _________.
Artificial spaces in tissue (wasted space because tissues are too close to each other)
Hepatocytes are found in the_______.
Liver
Purkinje cells are ______ found in the ________.
nerve cells, brain
Transmission electron microscopes and Scanning electron microscopes both use an __________ to display images.
Electrobeam
Transmission electron microscopes have ______ resolution and allows magnification up to ______ times.
Do we see multiple cells, 1 cell or a small portion of the cell on TEM’s?
High at 400,000x resolution
We see a small portion of the cell
Scanning electron microscopy only shows the _____________. Inside of organs are viewed by ___________. The resolution is ________.
surface view with 3D view of structures of that view, freezing and fracturing tissue to expose internal surfaces. The resolution is 10 nm.
What is the difference between TEM and Scanning Electron Microscopy? What is the similarity?
TEM and SEM both use electron beams to scan a cell. TEM allows you to look THROUGH the cell while SEM allows you to look at the surface view of a cell with 3D projections of things on that view.
Cells are surrounded by a ________.
Plasma Membrane
The nucleus is a ___________ compartment that contains ________.
Membranous, genetic information
What are the 2 functions of the nucleus?
Cellular Recognition and production of ribosomal subunits in the nucleolus
The __________ faces the cytoplasm. It has _____________ and is continuous with the _________.
Outer nuclear membrane, ribosomes , RER at certain sites.
Ribosome - continuous with RER
The ___________ faces the nuclear material and is supported on its ______ by __________.
inner nuclear membrane, inner surface, nuclear lamina
What are the 2 functions of the inner nuclear membrane?
Stability to nucleus and attachment site for chromosomes
Mutations in nuclear lamina can cause ___________.
Muscular Dystrophy
Molecules larger than 9nm are transported into nucleus by ____________
an active process that it mediated by receptors
_______ and ________ can cross the water-filled channels of the ________ by __________ to enter the nucleus.
Ions and water-soluble molecules, Nuclear Pore Complex, simple diffusion
A nucleosome is _______________. It is the basic subunit of ___________.
DNA sequence wrapped around a core of histone proteins. It is the basic subunit of chromatin packed in the cell nucleus.
Heterochromatin is __________ chromatin. Does it have active transcription?
How does it appear on a TEM?
condensed, tightly wrapped. It does NOT have active transcription
Heterochromatin will appear as dark stains in the nucleus of a TEM.
Euchromatin is ________. Does it have active transcription?
How does it appear on a TEM?
open conformation of chromatin. It does have active transcription
Euchromatin will appear as a lighter, less dense stains.