CS&B - Histology - Intro; Cell Structure Flashcards by Jason Worley

What are the three basic visualization methods of histology?

Light microscopy,

fluorescent microscopy,

electron microscopy

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What are three of the most common stains of light microscopy?

Hematoxylin and eosin (H&E);

periodic acid-Schiff (PAS);

Masson’s trichrome

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What is the most common stain of light microscopy?

Hematoxylin and eosin (H&E)

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What are the two principal colors of hematoxylin and eosin staining?

Blue and pink

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What color is hematoxylin?

What color is eosin?

Blue-ish

pink-ish

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In hematoxylin and eosin (H&E) staining, what are some structures that will be stained blue?

The nucleus;

keratohyalin granules and calcified material

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In hematoxylin and eosin (H&E) staining, what are some structures that will be stained pink?

Cytoplasm, collagen, lewy bodies, and mallory bodies

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The blue-pink differences in structures stained with H&E are largely due to what characteristic of the tissue being stained?

The relative pH

(acidic - nuclear components;

basic - proteins)

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Hematoxylin and eosin staining is a common stain in what modality of histology?

Light microscopy

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What is the periodic acid-Shiff (PAS) stain used for in light microscopy?

Staining specific cellular compartments, carbohydrates

(Note: the histology in the image is counterstained with hematoxylin)

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What stain is often used as a counter-stain with PAS to illustrate the nuclei?

Hematoxylin

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What are three substances often visualized with a periodic acid-Schiff (PAS) stain?

What color are they stained?

Mucins, glycogen, glycocalyx;

pink or magenta

(Note: the histology in the image is counterstained with hematoxylin)

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Which stain is especially good for connective tissue and collagen visualization?

Masson’s trichrome

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What science is the 3D interpretation of 2D cross sections of materials or tissues?

Sterology

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What is the most common histological stain?

What stain is useful for visualizing the nucleus in blue and surrounding cytoplasm/collagen in pink?

What stain is useful in visualizing cellular compartments and carbohydrates?

What stain is useful in visualizing muscle fibers as red, collagen as blue, cytoplasm as pink, and the nucleus as dark brown?

Hematoxylin & eosin (H&E);

hematoxylin & eosin (H&E);

periodic acid-Schiff (PAS);

Masson’s trichrome

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For what structures is the hematoxylin & eosin (H&E) stain useful? What colors are these structures stained?

The nucleus (blue) surrounding cytoplasm/collagen (pink)

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For what structures is the periodic acid-Schiff (PAS) stain useful? What colors are these structures stained?

Cellular compartments and carbohydrates (magenta)

(Note: Hematoxylin is often used as a counterstain when PAS is used)

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For what structures is the Masson’s trichrome stain useful? What colors are these structures stained?

Muscle fibers (red),

collagen (blue),

cytoplasm (pink),

the nucleus (dark brown)

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For what structures is the hematoxylin & eosin (H&E) stain useful? What colors are these structures stained?

For what structures is the periodic acid-Schiff (PAS) stain useful? What colors are these structures stained?

For what structures is the Masson’s trichrome stain useful? What colors are these structures stained?

The nucleus (blue) surrounding cytoplasm/collagen (pink)

Cellular compartments and carbohydrates (magenta)

Muscle fibers (red), collagen (blue), cytoplasm (pink), the nucleus (dark brown)

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What histological stain is used in this image?

Hematoxylin & eosin (H&E)

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What histological stain(s) is(are) used in this image?

Periodic acid-Schiff

(with hematoxylin counterstain)

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What histological stain is used in these images?

Masson’s trichrome

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What color are erythrocytes in H&E staining?

Intensely red

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What study involves the interpretation of these 2D images to understand their 3D orientation and structure?

Sterology

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What are the three main portions of the cell?

Cell membrane; nucleus; cytoplasm

What are the three main portions of the nucleus?

The **nuclear envelope** (and pores); **chromatin** (eu- and hetero-); the **nucleolus**

Are there lipids, proteins, and/or carbohydrates in the cell membrane?

All three

What are three common types of inclusions found in the cytoplasm?

**Fat** droplets; **glycogen** granules; **lipofuscin** granules

What is a common type of protein found in the cytosol?

Enzymes | (hundreds and hundreds of types)

What are the three main contributors to the cytoplasm?

Cytosol, organelles, and inclusions

What is the external surface of the cell membrane called? What is the internal surface of the cell membrane called?

E-face P-face

What two lipid types are found in high concentrations in lipid rafts?

Cholesterol; glycosphingolipids

What is the function of lipid rafts in cell membranes?

To stabilize protein clusters and keep them in close proximity to one another (this allows for efficient inter-protein interactions)

What structure stabilizes protein clusters within the cell membrane and allows for close, more efficient inter-protein interactions?

Lipid rafts

Where are glycolipids found in the cell membrane?

The E-face

What purpose does cholesterol serve in the lipid membrane?

Increased rigidity / stiffness

What are the three main colors of the Masson's trichrome stain?

Red (keratin/muscle); pink (cytoplasm); blue or green (collagen)

On which surface of the cell membrane is spectrin found?

The P-face (protoplasmic)

On which surface of the cell membrane are the ECM proteins found?

The E-face (exoplasmic)

What term describes the bilipid cell membrane characteristic in which the associated lipids have hydrophobic *and* hydrophilic sections?

Amphipathic

What are the three main types of lipid found in the plasma membrane?

Phospholipids; cholesterol; glycolipids

How many main types of phospholipid are found in the lipid membrane?

Name the three phospholipid types found on the P-face of the plasma membrane.

Phosphatidylserine (PS) phosphatidylethanolamine (PE) phosphatidylinositol (PI)

Name the two phospholipid types found on the E-face of the plasma membrane.

Phosphatidylcholine (PC); sphingomyelin (SPH)

What are the two types of cell membrane protein?

Integral and peripheral

Transmembrane and lipid-anchored proteins of the cell membrane are ________ proteins.

Integral

How do bilipid membranes appear on electron microscopy?

As trilaminar layers (dark outer layers with a central light area)

The term glycocalyx encompasses what two types of structure?

Glycolipids and glycoproteins

What are some structures making up the dark layers of the plasma membrane as seen on electron microscopy?

Phospholipid heads; integral proteins; glycolipids

What are some structures making up the light layer of the plasma membrane as seen on electron microscopy?

Phospholipid tails; integral proteins; cholesterol

True/False. The E-face and P-face layers of the plasma membrane each have the same types of phospholipid in similar concentrations?

**False** *(the E-face has different phospholipids from the P-face)*

What modality must be used to directly visualize the cell membrane?

Electron microscopy

Sphingomyelin is abundant on which surface of the cell membrane?

The E-face

Which enzyme breaks down sphingomyelin? Where is this enzyme located?

Acid sphyngomyelinase; the P-face

Acid sphingomyelinase breaks down sphingomyelin inside what structures?

Lysosomes

Sphingomyelin is found in high concentrations on which surface of the plasma membrane? Acid sphingomyelinase is found in on which surface of the plasma membrane?

E-face; P-face

Is pinocytosis clathrin-dependent or -independent?

Clathrin-independent

Is phagocytosis clathrin-dependent or -independent?

Clathrin-independet

Is receptor-mediated endocytosis clathrin-dependent or -independent?

Clathrin-dependent

Which of the following is(are) clathrin-dependent? Which is(are) actin-dependent? **Pinocytosis** **Phagocytosis** **Receptor-mediated endocytosis**

Receptor-mediated endocytosis; Phagocytosis

What is unique about phagocytosis when compared to pinocytosis and receptor-mediated endocytosis?

It is actin-dependent

What is unique about receptor-mediated endocytosis when compared to pinocytosis and phagocytosis?

It is clathrin-dependent

Retrograde vesicular transport from the golgi apparatus to the ER is associated with what surface protein?

COP - I | (1)

Anterograde vesicular transport from the ER to the golgi apparatus is associated with what surface protein?

COP - II | (2)

What is V-snare? What is T-snare?

A vesicle-specific membrane protein; a target membrane -specific protein

What are some examples of non-membranous organelles?

Ribosomes; proteasomes; cytoskeleton

Ribosomes are present on which side of the RER cisternae (interior or exterior)?

The cytoplasmic (exterior) side

Cytochrome P₄₅₀ is present in large concentrations in what organelle of hepatocytes?

The SER

Which organelle of myocytes is used for calcium sequestration?

The smooth endoplasmic reticulum (a.k.a. the sarcoplasmic reticulum)

What family of enzymes is involved in phase I detoxification in the hepatocyte SER? What family of enzymes is involved in phase II detoxification in the hepatocyte SER?

Cytochrome P₄₅₀; UDP - glucuronosyltransferases

In what organ is the highest concentration of SER in the body?

The liver

Which side of the Golgi apparatus faces the RER and receives vesicles from it?

The *cis* face (convex)

Which side of the Golgi apparatus releases vesicles and faces the plasma membrane?

The *trans* side (concave)

In what direction do proteins enter the Golgi apparatus (from the RER) and leave it?

RER --\> cis Golgi apparatus --\> trans Golgi apparatus

What enzyme is added to synthesized proteins in the RER and cis Golgi apparatus to mark these proteins as future lysosomal enzymes?

Mannose-6-phosphate

What is the importance of mannose-6-phosphate? Where is it added to select proteins?

It marks lysosomal proteins; the RER and cis Golgi apparatus

What protein controls vesicle movement from the cis Golgi apparatus to the trans Golgi apparatus? What protein controls vesicle movement from the trans Golgi apparatus to the cis Golgi apparatus?

COP-II (anterograde); COP-I (retrograde)

What are four locations to which the Golgi apparatus sends synthesized products?

Lysosomes, secretory granules, plasma membrane, back to the RER

Where do both sulfation of certain tyrosine residues and addition of sialic acid to sugars occur?

The trans Golgi apparatus

Besides COP-I and COP-II, what other protein is important in Golgi apparatus vesicle formation? ## Footnote *(Hint: this protein is often involved in vesicles heading to lysosomes or the cell membrane)*

Clathrin

Which of the four locations to which the Golgi apparatus sends vesicles (the cell membrane, lysosomes, secretory granules, and the RER) receive **clathrin-coated vesicles** from the Golgi apparatus?

Lysosomes; secretory granules

What factor decides the relative abundance of mitochondria in a cell?

The energy demands of the cell

What types of nucleic acid are present in the mitochondrial matrix?

DNA, tRNA, mRNA, rRNA

What percentage of the proteins of the mitochondria are coded for by mitochondrial DNA?

\< 1%

The 'elementary particles' visualized on the matrix-side of the mitochondrial cristae refer to what structures?

ATP synthase

Where is mitochondrial DNA (and associated RNA and ribosomes) within the mitochondria?

The mitochondrial matrix

Why would mitochondria be found in the cell periphery near the inner leaflet of the plasma membrane?

The membrane active transport requires huge amounts of ATP

The enzymes of the electron transport chain are found in what structure?

The inner mitochondrial membrane

What is the order of endosome formation after pinocytosis or receptor-mediated endocytosis?

Early endosome --\> late endosome --\> lysosome ## Footnote *(early becomes late, then fuses with a lysosome)*

At what stage do vesicles of pinocytosis and receptor-mediated endocytosis enter the following pathway: **Early endosome --\> late endosome --\> lysosome** At what stage do vesicles of phagocytosis enter the above pathway? At what stage do vesicles of autophagy enter the above pathway?

Early endosome; late endosome; lysosome

What is a primary lysosome? What is a secondary lysosome?

A lysosome that has nothing to digest; a lysosome that has fused with with a late endosome or phagosome or cytoplasmic organelle

What are residual lysosomal bodies? Of what are they typically full?

The non-digestible remains of whatever was initially in the lysosome to be digested; lipofuscin

What term refers to the lysosomal digestion of materials brought into the cell via endocytosis? What term refers to the lysosomal digestion of old cellular organelles?

Heterophagy; autophagy

What membrane-bound organelles are the site of intracellular digestion? What membrane-bound organelles break down fatty acids and contains both myeloperoxidase and catalase? What non-membrane-bound organelles destroy ubiquinated proteins?

Lysosomes; peroxisomes; proteasomes

Via what two methods are intracellular proteins destroyed?

**Lysosomes** (autophagy); **proteasomes** (following ubiquination)

What two substances are often found in intracellular inclusions as a form of energy storage?

**Glycogen** (clumped granules); **lipids** (spherical, single monolayer droplets)

What is the most common pigment of the body? What pigment is common in old cells? What pigment is related to the phagocytosis of RBCs and hemoglobin?

Melanin; lipofuscin; hemosiderin

Melanin, lipofuscin, and hemosiderin all appear somewhat similarly in histology. They be differentiated according to what?

The type of tissue in which they are found

What is the term for the images produced by microscopy?

Micrographs

What type of electron microscope created this image? ## Footnote *(Note: the electrons did not go through the structure)*

Scanning electron microscope

What type of electron microscope created this image? ## Footnote *(Note: the electrons did go through the structure)*

Transmission electron microscope

What cellular structure(s) is(are) responsible for cell polarity, intracellular vesicular movement, and organelle placement/anchoring?

The cytoskeleton

What cellular structure (broadly speaking) is responsible for cellular shape, cell motility, and cellular adhesion?

The cytoskeleton

How big are each type of cytoskeleton (on average, in nm)?

Microfilaments - **7 nm** Intermediate filaments - **8-12 nm** Microtubules - **25 nm**

What are some functions of microfilaments?

Cytoplasmic transport, cellular motility, cell shape, microvili support (microfilaments are basically just actin)

From where do microtubules radiate throughout the cell?

The centrioles and axonemes

Describe where microfilaments are found in highest concentrations in the cell.

Cell wall, microvili

Describe where intermediate filaments are found in highest concentrations in the cell.

Throughout the cytoplasm

What type of cytoskeleton maintains nuclear shape?

Intermediate filaments

Describe where microtubules are found in highest concentrations in the cell.

Radiating throughout the cytoplasm from centrioles and axonemes

Which type of cytoskeleton is the most stable?

Intermediate filaments

Describe the general cytoskeleton.

Which type of cytoskeleton is responsible for chromosomal movement during mitosis? Which type of cytoskeleton is responsible for cellular cleavage during mitosis?

Microtubules; microfilaments

Describe some microfilament organizational patterns that have different roles in the cell.

Is actin a globular or filamentous protein?

Both; it is filamentous when polymerized, but the polymer is made of small, globular monomers

What does it mean that actin is polar?

It has a plus end and a minus end

What are a few examples of the many types of intermediate filaments?

Myosin, spectrin, vimentin, lamin

What cytoskeletal component gives microvili projections their form? What cytoskeletal component makes up the terminal web that anchor the microvili?

Microfilaments (and some myosin connecting them); intermediate filaments

What is another name for the intermediate filament anchoring the base of microvili in place?

The terminal web

What intracellular intermediate cytoskeletal protein is especially relevant to the P-face of erythrocytes?

Spectrin

How does intracellular spectrin maintain cell membrane integrity?

It **forms tetramers** and anchors **actin**

In erthrocytes, what protein anchors the spectrin-actin complex to the cellular membrane?

Ankyrin

What protein carries vesicles down towards the plus end of microtubules? What protein carries vesicles down towards the minus end of microtubules?

Kinesin; dynein

The plus end of a microtubules is closer to the centriole or cell periphery? The minus end of a microtubules is closer to the centriole or cell periphery?

Periphery; centriole

Which globular tubulin monomer is on the plus end of a microtubule filament? Which globular tubulin monomer is on the minus end of a microtubule filament?

What intermediate protein is especially present in lymphocytes? What intermediate protein is especially present in all types of muscle? What intermediate protein is especially present in astrocytes?

Vimentin; desmin; GFAP

What intermediate protein is especially important to connective tissue? What intermediate protein is especially important to epithelial cells? What intermediate protein is especially important to neurons?

Vimentin; cytokeratin; neurofilament

What intermediate protein is especially important to nuclear membranes? What intermediate protein is especially important to some Schwann cells? What intermediate protein is especially important to erythrocyte cell membranes?

Lamins A, B, and C; GFAP; spectrin

What cytoskeletal structure provides the basis of the mitotic spindle? What cytoskeletal structure provides the basis of the cellular cilia? What cytoskeletal structure provides the basis of the cellular flagella?

Microtubules; microtubules; microtubules

What two structures make up a single centrosome?

The centrioles | (at right-angles to one another)

Where is the centrosome typically located? What are some other locations?

Near the nucleus

What is a nucleosome?

A single histone unit and its associated double-stranded DNA

The nucleolus is largest and most well-developed in what type of cells?

Highly transcriptionally active cells

Which of the following cell structures would stain with a basic dye after treatment with RNAse? Chromatin Nucleolus SER RER Golgi

**Chromatin** (the basic dye is binding to the acidic structure)

Is hematoxylin basic or acidic?

Basic | (it binds acidic structures)

What gives the nucleolus its deep blue color when stained with hematoxylin?

High concentration of ribosomes (RNA)

Which of the following would stain blue when stained with hematoxylin and eosin? Chromatin Nucleolus RER All three

**All three**

Which of the following would stain the **deepest** blue when stained with hematoxylin and eosin **after** treating the cell with RNAse? Chromatin Nucleolus RER All three

**Chromatin** (the ribosomes and other RNA types of the RER and nucleolus have been degraded)

Which protein is responsible for cilia and flagellar movement?

Axonemal dynein

Addition of what chemical structure to dynein causes cilia or flagellar movement?

**Phosphate** | (from ATP)

Does axonemal dynein interact with the outer, inner or both microtubules found in cilia or flagella?

Outer

What three subunit proteins make up the ankyrin protein?

Band-3, ankyrin, band-4

Describe the axonemal arrangement of cilia and flagella.

**Axoneme**: **9** microtubule **pairs** surrounding **two** central microtubule filaments (with inner and outer dynein arms)

Alpha-tubulin binds to what structure in the centriole?

Gamma-tubulin

As what are the individual tubulin filaments in a microtubule referred?

Protofilaments

One microtubule is made up of how many tubulin protofilaments? One mature ciliar/flagellar axoneme is made up of how many microtubules?

13; 20 (9 pairs m. surrounding 2 central m.)

A centrosome is made of two perpendicular centrioles. How many microtubules make up one centriole?

9 triplets (27 total m.)

How many tubulin protofilaments would be found in one centrosome?

702 (13 protofilaments / microtubule x 3 microtubules / triplet x 9 triplets / centriole x 2 centrioles / centrosome)

What happens to the centriole during the beginning of cell division?

It replicates

This is an electron micrograph of the cross-section of what structure?

The axoneme of a flagellum or cilium

Which microtubule of any axonemal pair has the complete 13 protofilaments? Which one is not complete and shares some of the complete one's protofilaments?

A; B

Which microtubule of an axonemal pair has attached inner and outer dynein? Which microtubule of an axonemal pair has attached radial spokes?

A; A

What is the name of the specialized centriole at the base of a ciliar or flagellar axoneme?

The basal body

The basal body of a flagellum or cilium is made of how many microtubules? A centriole is made of how many microtubules?

9 triplets; 9 triplets

How will a transcriptionally active cell's chromatin appear?

Large areas of euchromatin

Chromatin is made of what structure(s)?

DNA and proteins

What is the site of ribosomal synthesis? What is the site of ribosomal assembly?

The nucleolus; the nucleolus

The outer membrane of the nuclear envelope is continuous with what structure?

The RER

How thick are euchromatin strands? How thick are heterochromatin strands?

11 nm; 30 nm

What is the name of the DNA between nucleosomes?

Linker DNA

Chromatids are connected at what point?

The centromere

A cell with a dark, splotchy nucleus is likely transcriptionally \_\_\_\_\_\_\_. A cell with a light, clear nucleus is likely transcriptionally \_\_\_\_\_\_\_.

Inactive (+heterochromatin); active (+euchromatin)

What is indicated by **G** in this electron micrograph of a nucleous? What happens here?

Granular material; initial ribosomal assembly

What is indicated by **F** in this electron micrograph of a nucleous? What happens here? What is contained here?

Fibrillar material; sites of active transcription; rRNA

What is indicated by **FC** in this electron micrograph of a nucleous? What is contained here?

Fibrillar centers; the DNA sequences for the rRNA genes, transcription factors

Where is DNA synthesized? Where is RNA synthesized? Where is protein synthesized?

The nucleus The nucleus The cytosol

What lies between the inner and outer nuclear membranes? This space is continuous with what?

The perinuclear cisternal space; the RER cisternal space

The square lattice / meshwork that supports the inner nuclear membrane is known as what? (of what is it composed?)

The nuclear lamina (made of lamin A and lamin B - types of intermediate filament)

Active transport in and out of the nucleus occurs at what sites? What makes up these sites?

Nuclear pores; nucleoporins protein complexes

What targets proteins for transport into the nucleus? What targets proteins for transport out of the nucleus?

Nuclear localization signal; nuclear export signal