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.
The nucleolus appears as a _________ on a TEM.
Large, dense black circle.
The nucleolus is basophilic or acidophilic? What color will it stain with H&E?
Basophilic, it will stain blue
The nucleolus is the site of __________ synthesis and initial ______________.
ribosomal RNA (rRNA) and initial ribosome assembly
Ribosomal RNA appears as __________ while the RNA polymerase required to assemble the rRNA appears __________
Strings exuding from the central DNA strand
Small dots ON the DNA strand
What is rRNA?
The major component of ribosomes.
Ribosomes are assembled in the _______________ and transported to the ____________ where they serve as _______________.
nucleolus, cytoplasm, the site for protein synthesis.
The nucleus is basophilic or acidophilic?
Basophilic
What is the difference between the cytoplasm and the cytosol?
The cytoplasm is everything in the cell membrane but outside the nucleus. The cytosol is the actual intracellular fluid.
Cytoplasm is essentially cytosol + organelles
Ribosomes are membranous. True or False?
False
Ribosomes read the _________ and translates it into _______ which form ________.
mRNA , amino acids , proteins
Ribosomes can be free or bound to the ________.
RER
The ER is made of _________ and ________ formed by a ______________.
intercommunicating channels , sacs and cisternae, continuous membrane
What is inside the sacs and cisternae?
Fluid
Is the SER or RER continuous with the outer nuclear membrane?
RER
What are polyribosomes and where are they located?
Polyribosomes are ribosomes associated with the cytosol and RER. They are ribosomes associated with mRNA.
How does a polyribosome appear on a TEM?
A swirl pattern with small dots near the rest of the RER
What are the functions of the RER?
Protein synthesis
What is the fate of the proteins that are produced by the RER?
- They can remain in the cell
- They can be incorporated into membranes
- They can enter the nucleus
- They can be secreted/exported from the cell.
What is an important modification of eukaryotic proteins required for recognition signals?
Glycosylation
What is glycosylation and where does it occur?
Glycosylation is the addition of sugar residue trees of GLYCAN to the asparagine residue of eukaryotic proteins to be used as recognition signals.
There are 2 types of glycosylation.
N-linked which begins in the ER.
O-linked which begins in the gOlgi body
What is constitutive secretion? What is an example of a constitutive secretor?
Cell is secreting 24/7.
Hepatocytes
What is regulated secretion? What is an example?
Cell secrets when signaled.
Pancreatic Acinar Cells, plasma cells-antibodies
What is the difference in structure of constitutive and regulated secretors?
There is a difference in how the RER is organized and where it is located in the cel.
Secretory granules are located ___________. Content of the granule is stored in __________- until ___________.
Apically. Contents are stored in the granules until needed.
What are the 4 functions of the SER?
- Synthesis and breakdown of glycogen
- Detoxification of drugs/metabolic wastes
- Synthesis of lipoproteins, cholesterol, bile and salts
- Synthesis of steroid hormones.
- Uptake and release of calcium in muscle cells
Glycogen is broken down in __________ by the __________.
the liver, SER
The uptake and release of calcium in muscle cells is controlled by the __________.
SER
Describe the structure of the golgi body
Stacks of membrane-bound disc shaped envelopes called cisternae. It has a cis face for receiving and a trans face for exporting.
Is the golgi body membranous?
Yes
What happens to proteins produced by the ER?
Proteins produced by the ER that are properly folded will move via small vesicles to the Golgi Complex.
The golgi body functions to ___________ and __________ as well as ___________.
make post translational modification of proteins
Synthesize lipoproteins
O-linked glycosylation.
Lipoproteins are produced by the __________.
Golgi body
N-Linked glycosylation is the addition of a _________ to a ___________ of an ____________. This occurs in the _______.
Glycan , nitrogen molecule of an asparagine amino acid.
RER
O-linked glycosylation is the addition of a ___________ to a __________ of an _________. This occurs in the __________.
Glycan, oxygen molecule of amino acid
Golgi body
Which glycosylation is more common?
N-linked
The mitochondria is surrounded by a __________ with _________.
double membrane, internal cristae
What are the 3 functions of the mitochondria?
Energy production and beta-oxidation of long chain fatty acids and steroid hormone synthesis
Where does beta-oxidation of long chain fatty acids occur?
Matrix of mitochondria and perioxisomes
Where does steroid hormone synthesis occur?
It occurs at the mitochondria. They are at the site at which the side chain on the cholesterol is cleaved.
What enzyme system performs the steroid hormone synthesis and where is it located?
The desmolase system is located on the inner mitochondrial membrane
What is the precursor to progesterone, aldosterone and testosterone?
Pregnenolone
The _________ and _________ are involved in the storage and release of calcium to regulate _______.
SER and mitochondria
apoptosis
Mitochondrial _______ and ________ give rise to the concept that mitochondria were evolved from __________.
ribosomes and DNA
bacteria that were symbiotic with cells
Lysosomes are membrane bound organelles. True or False
True
Lysosomes contain ________ making them ________. They also have __________.
Hydrolytic enzymes, acidic
Electron-dense heterogeneous contents
What maintains the acidic interior of a lysosome?
Proton pump
Lysosomes function to _______________.
digest ingested material and aged/damaged organelles
What is heterophagy and which organelle is responsible for it?
Phagocytosis and degradation of bacteria via a neutrophil through the lysosome.
What is autophagy and which organelle is responsible for it?
Destruction of aged/damaged organelles via lysosome
Which organelle is responsible for the break down of bone during bone remodeling?
Lysosomes
What cells are responsible for breaking down bone?
Osteoclasts
Primary lysosomes ________.
Secrete hydrolytic enzymes into special microenvironments. (Osteoclasts)
Secondary lysosomes _________
Perform phagocytosis of bacteria or debris
Lysosome storage disease can be caused by ___________.
a mutation in the gene that encodes for lysosomes or an accumulation of the substrates for lysosomal digestion.
Fabry Disease. What organelles is it associated with?
Abnormal storage of lipids , Lysosome
Gaucher’s Disease.What organelles is it associated with?
Skeletal disfigurement, Lysosome
Mannodidosis. What organelles is it associated with?
Causes problems in many organs and tissue, lysosyme
MLD, What organelles is it associated with?
Affects CNS , Lysosome
MPS. What organelles is it associated with?
Affects bone, cartilage, tendons, corneas, skin and connective tissue, Lysosome
Neimann Pick, What organelles is it associated with?
Enlargement of spleen or liver, Lysosome
Pompe Disease.
Glycogen accumulates in lysosomes causing damage to muscle and nerve cells
Peroxisomes are membrane bound. True or false?
True
Peroxisomes contain ________. They function to ______________ and ______________
degrade hydrogen peroxide
Lipid metabolism including beta oxidation of fatty acids
Peroxisomes are or are not made in association with the Golgi Complex?
NOT
What feature on a TEM indicates a peroxisome?
Crystalloid core. Looks like large dark line or circle in the peroxisome
What disease is caused by the absence of peroxisomal enzymes? Is it fatal?
Zellweger’s/ Cerebrohepatorenal Syndrome
What is Zellweger’s Syndrome?
Due to the absence of peroxisomal enzymes, there is reduced degradation of cytotoxic hydrogen peroxide and accumulation of VLCFA’s causes neuronal membrane injury and demyelination.
What are key features of Zellweger’s Syndrome?
Skeletal muscle weakness, inability to nurse properly, neurological disorders, seizures, large liver, kidney cyst
The cytoskeleton is unique to _____________. It fits inside the ___________- and made of ______________.
Eukaryotic cells
cytoplasm
microtubules, microfilaments , intermediate filaments
Glycogen is a ________. It is mostly located in ________. It will stain _____ on a PAS.
Storage molecule for glucose
Liver and striated muscle cells
Red
Lipids are abundant in some cells which can be used as ____ and ______. Are they membranous?
energy storage and steroid hormone formation
No
What are inclusions (3) ?
Glycogen, lipids, and secretory granules
The plasma membrane is a ________ with _________, ______,______ with ____________ linked ____ to ________.
lipid bilayer
Phospholipids
Proteins
Carbs
Oligosaccharide chains covalently linked to phospholipids and proteins
The phospholipid head faces the ______ and is __________. The tails face _______ and are _________.
ECM and cytoplasm, Hydrophilic
Each other, Hydrophobic
What are the 4 functions of the plasma membrane?
Physical Barrier
Selective permeability
Electrochemical gradient
Communication
What is the glycocalyx and how does it form?
The glycocalyx is the cell sugar goat that forms by carbohydrates attaching to proteins to make glycoproteins.
What is the function of the glycocalyx?
Metabolism, cell recognition, cell association ,receptor sites for hormones
