Cytology Flashcards
(215 cards)
1
Q
What is a Feulgen stain for? Color?
A
Nuclei (specifically DNA) stains red
2
Q
What is a H&E stain for?
A
Nuclei (DNA), nucleoli (RNA), and basophilic structures (RNA in rER & ribosomes) stain blue
Cytoplasm and acidophilic structures (cytoplasmic proteins) stain pink
3
Q
What is a hematoxylin stain for? Color?
A
Stains DNA (nuclei), RNA (nucleoli), and basophilic structures (ribosomes, rER) blue
4
Q
What is an eosin stain for? Color?
A
Stains the cytoplasm and acidophilic structures (cytoplasmic proteins) pink
5
Q
What is a Periodic-Acid Shift (PAS) stain for? Color?
A
Stains carbohydrates and carbohydrate-rich molecules red
Glycogen, starch, cellulose, mucin, collagen, cartilage-matrix, thyroid colloid
6
Q
What is a Silver Impregnation for?
A
Stains Golgi, reticulum, nerve fibers, and cell borders of the mesothelium
7
Q
What does Osmium Tetroxide stain?
A
Stains Golgi, myelin, and lipids
8
Q
What does Methyl Green stain?
A
DNA stains green
9
Q
What does Pyronin stain?
A
RNA stains red
10
Q
What does Phosphotungstic Acid Hematoxylin (PTAH) stain? Color?
A
Stains mitochondria, nuclei, and contractile elements of striated muscle blue/purple
11
Q
What is an artefact?
A
A flaw on a slide caused by a faulty technique
12
Q
What can be used as a “ruler” when viewing cells with a light microscope?
A
RBCs are approximately 7-8 um
13
Q
What are possible causes for an artefact?
A
- Postmortem degradation
- Shrinkage
- Precipitation
- Wrinkles & folds
- Nicks
- Technician handling
14
Q
Four common features of cells
A
- Surrounded by membrane
- Have nuclei (zero for RBCs)
- Contain organelles (membrane or non-membrane bound)
- Contain inclusions (nonliving material)
15
Q
Functions of the nucleus
A
- DNA replication (for cell division)
- DNA repair
- RNA transcription and processing
16
Q
What are the three major components of the nucleus?
A
Nuclear envelope, chromatin, and nucleolus
17
Q
Why is the evaluation of the morphology of the nucleus important?
A
Helps determine the health of the cell
Ex: tumor cell development
18
Q
What are the key features of the nuclear envelope?
A
Has two unit membranes (outer and inner) 10-30 nm apart that are separated by the perinuclear cisternae and are continous with one another at the nuclear pores
Has lamin proteins near inner membrane
19
Q
What is the perinuclear cisternae?
A
Space between the two unit membranes of the nuclear envelope (10-30 nm)
20
Q
What is the difference between the inner and outer membranes of the nuclear envelope?
A
Inner membrane faces nuclear matrix, associates with the chromatin and is supported by the nuclear lamina
Outer membrane faces the cytoplasm, is continuous with (shares biochemical/functional properties) rER, can have ribosomes attached
21
Q
Functions of the nuclear pores
A
Act as bidirectional gates between cytoplasm and nucleus
Allows small molecules to pass via diffusion (8-9 nm)
All proteins with a nuclear localization amino acid sequence are transported via active transport
22
Q
What is the nuclear localization AA sequence?
A
The amino acid sequence that allows proteins to pass through the nuclear pores via active transport
23
Q
Small proteins can pass through the nuclear pores via facilitated diffusion. T/F
A
False, proteins of all size need a nuclear localization AA sequence to pass via active transport
24
Q
Structure of the nuclear pore
A
Two octagonal rings (cytoplasmic and nuclear) made from 8 nucleoporin (nuclear pore proteins) subunits each that form central pore (70-80 nm)
Protein filaments extend from both rings, but form basket on nuclear side (allow reactions to occur)
25
If you were able to inject a dye into the perinuclear cisternae where could that dye be found if it were free to move in the cisterna?
Lumen of the rER (because outer leaflet is continuous with rER, dye could move into that region)
26
Why do we call the boundary of the nucleus a nuclear envelope instead of a nuclear membrane?
The nucleus is surrounded by two unit membranes separated by a perinuclear cisterna (space). Therefore it is called a nuclear envelope.
27
What structures associated with the nuclear envelope can be seen with the electron microscope?
- Inner nuclear membrane
- Outer nuclear membrane with associated ribosomes
- Perinuclear cisternae
- Nuclear pores
- Nuclear lamina
- Continuity of the outer nuclear membrane with the rER
28
Functions of the nuclear lamina
- Gives shape/stability to nuclear envelope
- Links chromatin and nuclear envelope
- Holds pores in nuclear envelope
- Dissolves/reforms nuclear envelope during cell division (via phosphorylation)
- Organizes the interphase nucleus
29
Location and structure of nuclear lamina
Between inner nuclear membrane and heterochromatin, made lamins A, B, C (intermediate filament proteins)
30
What does phosphorylation of the nuclear lamins cause?
Dissolves nuclear lamina during mitosis/cell division
31
What are envelopathies and laminopathies?
Mutations in the proteins of the nuclear membrane or lamins
32
Chromatin
Complex made of DNA, histone and non-histone proteins in the nucleus of eukaryotic cells
33
Heterochromatin
Condensed DNA of genes that are not being transcribed, can be constitutive (never transcribed) or facultative (transcription depends on cell type)
34
What does heterochromatin look like in a light microscope?
Appears as basophilic clumps
35
Euchromatin
Uncoiled / loosely packed DNA of genes that are being transcribed
Aka extended chromatin
36
Nucleosome
Looks like nucleosome beads on a DNA string, is the simplest arrangement of chromatin packing in the nucleus (11 nm wide)
DNA makes 1.75 turns around 8 proteins (four histone types in pairs, called nucleosome) connected by linker DNA
37
30 nm chromatin fibrils
Nucleosomes coil into threads/fibrils due to different histone types binding together
38
300 and 700 nm chromatin fibers
The coiled 30 nm fibrils are looped into 300 nm loops, which are further coiled into 700 nm helical loops (chromosomes of metaphase)
39
What packaging structure is seen with a light microscope in mitotic/meiotic cells during metaphase?
700 nm chromatin fibers of condensed chromosomes
40
What is the order and size of the packing structures of DNA in the nucleus?
```
Helical DNA (2 nm)
Nucleosome (11 nm)
30 nm chromatin fibrils
Chromatin fibers (300 and 700 nm loops)
Chromosomes (1400 nm)
```
41
Genotype
of chromosomes in somatic cells, species specific (humans = 46)
42
Karyotype
Standard map of the banding pattern of each chromosome during metaphase stage
43
Autosomes
Chromosomes that are not sex chromosomes (humans = 22)
44
Sex chromosomes
One pair per cell
| XX or XY
45
Barr body
The inactive X chromosome of females
Seen as drumstick
or heterochromatin clump next to nuclear envelope in light microscope, more obvious in WBCs
46
Chromatid
One copy of a chromosome formed by DNA replication still joined at the centromere to the other copy
47
Diploid
Cells with full complement of chromosomes (humans = 46)
48
Haploid
Having only one of each pair, like germ cells (23)
49
Polyploid
Having more than one complement of chromosomes
50
Aneuploidy
Any deviation in the normal number of chromosomes
51
What are examples of aneuploidy?
Trisomy - 3rd chromosome of one type (Down's syndrome, Klinefelter's syndrome)
Monosomy - absence of chromsome in pair (Turner's syndrome XO)
52
Nucleolus
Eccentric, not surrounded by membrane, 1-2 per cell (depends on species/activity of cell)
Site of rRNA transcription, has nucleolar organizing region
53
Location of the nucleolus
Eccentric circle of condensed DNA not surrounded by membrane
54
How many nucleoli are found in cells?
1-2 depending on species and activity of cell
55
Function of the nucleolus
Site of rRNA transcription primarily
| Also regulates the cell cycle with nucleostemin (protein contained in nucleolus that stops G1
56
Nucleolar Organizing Region (nuclear associated chromatin)
10 expanded chromosomes (pairs of 5) that contain genes that encode rRNA, also helps to reorganize the nucleoli after cell division
The DNA transcription loops of the NOR chromosomes form circle that is the nucleolus
57
Composition of the nucleolus
Lots of rRNA and protein (basophilic)
58
Areas of the nucleolus
- Fibrillar center - stains pale
- Pars fibrosa - dense fibrillar region
- Pars granulosa - granular compartment
59
Structure of the ribosome
Large subunit - 60S, catalyzes peptide bond formation, made of 28S, 5S, and 5.8S rRNA
Small subunit - 40S, binds mRNA and tRNA in cytoplasm, recruits large subunit, made of 18S
60
Formation of ribosomes
In nucleolus: Nucleolar organizing DNA is transcribed to form pre-rRNA, which associates with ribosomal proteins (forms ribonucleoproteins), pre-rRNA is cleaved into 28S, 18S, and 5.8S rRNAs
In nucleus: 28S and 5.8S combine with 5S rRNA (transcribed in nucleus) to form large ribosomal subunit, then ribosomal subunits are actively transported through nuclear pores into cytoplasm
In cytoplasm: Ribosomal subunits assemble into ribosomes/polysomes with mRNA
61
Translation of mRNA into proteins by ribosomes takes place in nucleus. T/F
False, translation takes place in the cytoplasm
62
Ribosomal subunits are transported out of the nucleus with simple diffusion. T/F
False, nuclear pores use active transport to move proteins in and out of the nucleus
63
All rRNA are transcribed in the nucleolus. T/F
False, the 5S rRNA is transcribed in the nucleus and assembles into the large subunit in nucleus
64
What events of the formation of ribosomes takes place in the nucleolus?
Transcription of pre-rRNAs, association of pre-rRNAs with ribosomal proteins, and cleavage of rRNAs into 28S, 18S, and 5.8S
65
What events of the formation of ribosomes takes place in the nucleus?
Assembly of the 5S, 28S, and 5.8S rRNA into the large ribosomal subunit and active transport of ribosomal subunits out of the nucleus through nuclear pores
66
What events of the formation of ribosomes takes place in the cytoplasm?
Assembly of the ribosomal subunits into the ribosome / polysomes in association with mRNA
67
Four key concepts of membranes
1. They are not homogenous
2. Membrane components are in constant dynamic flux
3. Membranes are asymmetric (outer and inner leaflet totally different)
4. The shape of the surface membrane is partly determined by the underlying cytoskeleton
68
What nuclear components can be seen with the light microscope?
Nuclear envelope, heterochromatin, and nucleolus
69
Structure of the unit membrane
Trilaminar structure (3 distinct layers) when viewed with EM (outer and inner leaflet electron dense)
70
What substance is responsible for half of the mass of membranes?
Lipids
71
What is the function of lipids in the membrane?
Responsible for membrane form and permeability
72
What is the most abundant type of lipid in the membrane?
Phospholipids
73
What is the second most abundant type of lipid in the membrane?
Cholesterol
74
What is the function of cholesterol in membranes?
Maintains the structural integrity
75
What is the third most abundant type of lipid in membranes?
Glycolipids
76
Where are glycolipids always found in membranes?
Outer leaflet
77
Order the three most common lipids found in membranes from most abundant to least abundant
Phospholipids > cholesterol > glycolipids
78
What is the function of proteins in membranes?
Give the membrane its specific functions
79
What type of molecules are permeable to the unit membrane? What type aren't?
Small hydrophobic (oxygen, CO2, nitrogen, and benzene) and small, uncharged, polar molecules (water, urea, glycerol) are permeable
Large, uncharged, polar molecules (glucose, sucrose) and ions (H+, HCO3-) are not permeable
80
How is the presence of membrane proteins indicated?
Using the freeze fracture technique
81
What are common specific functions of membrane proteins? (6)
Enzymes, channels, receptors, cell-cell recognition, intercellular junctions, bind to cytoskeleton/ECM
82
Where are carbohydrates located on the unit membrane?
Outer leaflet
83
What does the carbohydrate component of the membrane contribute to?
Glycocalyx
84
What is the function of the glycocalyx?
Cell recognition
85
What is the structure of the glycocalyx?
Made of glycolipids and glycoproteins coated in carbohydrates
86
Lipid raft
Floats in plasma membrane and groups proteins that need to interact together
Has a specialized membrane domain (longer phospholipid tails, so only proteins with long transmembrane domains can enter)
87
Cytoskeleton
Dynamic network of protein filaments that organizes cytoplasm and gives cell shape
Made of microfilaments, intermediate filaments, and microtubules
88
Functions of the cytoskeleton
- cell motility
- organelle and vesicle transport
- muscle contraction
- cell division
- endocytosis/phagocytosis
- provides mechanical strength
89
Order the components of the cytoskeleton from smallest to largest
Microfilament (7 nm) < intermediate filament (10 nm) < microtubule (25 nm)
90
What is the major cytoskeletal protein of most cells?
Actin
| 5-10% of total cell protein
91
What is the diameter of microfilaments?
7 nm
92
What are microfilaments composed of?
Actin
93
Protein found on the outer and inner leaflets of unit membranes are the same. T/F
False, the protein are very different since each side faces a different compartment of the body and thus has different reactions/functions
94
Which side of the cell membrane is similar to the inner leaflet of a organelle membrane?
The outer leaflet, since molecules outside of the cell are brought in and out of the organelle and need to interact
95
Which side of the cell membrane is similar to the outer leaflet of a organelle membrane?
The inner leaflet, since both are facing the cytoplasm
96
Structure of a microfilament (mf)
Polar G-actin proteins bind head to tail to form polar protofilaments
Two protofilaments twist into helix to form F-actin filaments
The F-actin filaments have a positive (barbed) and negative (pointed) end
Can branch
97
Protoplasm
Individual masses of cells containing nucleic acids, proteins, lipids, carbohydrates, salts
98
Inclusions
Cell constituents that may or may not be membrane bound
| Of end product nature (produced by organelles)
99
The plasmalemma is an organelle. T/F
True, the cell membrane is an organelle
100
What type of appearance does the cell membrane show in an EM?
Trilaminar appearance when cells have been treated with osmium tetroxide
101
How are peripheral proteins bound to the cell membrane?
Ionic interactions
102
Where are bound carbohydrates typically located?
Bound to membrane proteins and polar head groups of lipids typically on EC surface
103
What is the collective term for the coating of carbohydrates on the plasma membrane?
Glycocalyx
104
Actin filaments can branch. T/F
True
105
Function of a microfilament (mf)
- Cell-cell and cell-matrix adhesion
- Cell shape
- Stability and function of microvilli
- locomotion/contraction
- Endo/exocytosis
106
Functions of actin-binding proteins
- Branching (Arp 2/Arp3)
- Regulate filament dynamics (filament growth)
- Organize filaments into 2-D networks (bundling proteins) or 3-D gels (gel-forming proteins)
- Actin-motor proteins use ATP to move to plus end
107
Treadmilling
Microfilament based movement where actin is added to one end while taking away actin on the other
108
Intermediate filaments
Provides mechanical strength to cells that are subject to stress
Made up of a variety of proteins that are specific for the cell type
109
The ___ domain of intermediate filaments is similar while the ___ are different and allows different interactions to occur.
Alpha-helical rod, amino and carboxy terminals
110
___ are the most stable cytoskeletal component.
Intermediate filaments
111
Structure of intermediate filament
Has similar alpha-helical rods with different amino and carboxy terminals
Wound into coiled coil like rope, then staggered to make tetramer (basic subunit of IFs)
112
Microtubules (MTs)
Polar, hollow cylinders of 13 parallel protofilaments composed of dimers of alpha and beta tubulin subunits
Plus end grows rapidly, minus end is embedded in MTOC
113
Both microfilaments and microtubules are branching. T/F
False, only MFs are branching
114
Centrosome
An MTOC composed of a pair of centrioles at right angle with 50 gamma-tubulin rings acting as template for MT growth
115
Centriole structure
Composed of nine triplets of MT
116
Functions of microtubules
- Cell shape
- Organelle transport
- Chromosome separation during mitosis/meiosis
- Ciliary/flagellar movement
117
Many functions of microtubules are due to the property of ___.
Dynamic instability
118
Dynamic instability
The rapid conversion between growing and shrinking of microtubules
Beta-tubulin subunit is enzyme that catalyzes hydrolysis of GTP into GDP, destabilizing the MT
GTP means its growing, GDP means its shrinking
119
Microtubule-Associated Proteins (MAPs)
Bind to MTs, organize MTs in bundles, stabilize MTs from disassembly, mediate interactions with other cellular components, organize cytoplasm functionally, increase rate of nucleation, act as molecular motors
120
Microtubule motor proteins
Some MAPs use ATP to move in a single direction along the filament
121
Kinesin
MT motor protein directed towards plus end
122
Dynein
MT motor protein directed towards minus end
123
Kinesin is directed towards the ___ end of MTs while Dynein is directed towards the ___ end.
plus, minus
124
The cell cycle consists of ___ and ___.
Interphase, mitosis
125
Interphase is composed of what four aspects?
G1 Phase, G0, S phase, and G2
126
G1 Phase
Cell growth, cell monitors its environment and size
127
G0
Resting state, near end of G1
128
S Phase
Replication of DNA, duplication of centrioles
129
G2 Phase
Safety gap, cell makes sure DNA replication is complete
130
Prophase
- Chromatin starts to condense
- Disassembly of cytoplasmic MTs
- Beginning of mitotic spindle formation
131
Prometaphase
- Nuclear envelope breaks down
| - Chromosomes attach to spindle
132
Metaphase
-Chromosomes align on metaphase plate
133
Anaphase
- Kinetochores separate
| - Movement of chromatids to opposite poles
134
Telophase
- Separated chromatids arrive at poles
- Kinetochore MTs disappear
- Polar MTs elongate
- Nuclear envelope reforms
- Chromosomes decondense
135
Cytokinesis
Cytoplasmic division
136
The replication of the centrioles occurs during the ___.
S Phase of interphase
137
During ___, MTs origininating from the centrosome increase.
Prophase
138
When do cellular MTs increase their rate of disassembly?
Late prophase
139
Structure of mitotic spindle
Polar MTs overlap at midline of spindle, push poles apart
Kinetochore MTs attach to kinetochore at centromere
Astral MTs radiate in all directions from centrosome to position poles in cell and help separate the poles
140
What three MTs are part of the mitotic spindle?
Astral MTs, kinetochore MTs, and polar MTs
141
How does cytokinesis take place?
A ring of actin and myosin filaments contracts to split cell
142
For dynamic instability, ___ means the MT is growing, while ___ means the MT is shrinking.
GTP, GDP
143
Annulate lamellae
Stacks of parallel lamellae (cisternae) with many pores (like nuclear envelope)
Occur in rapidly dividing cells (germ cells)
144
Endoplasmic reticulum
Largest membraneous system in cell consisting of interconnected tubules and vesicles
Two interconnected components: rER and sER
145
Smooth endoplasmic reticulum
- Prominent in cells that specialize lipid metabolism (hepatocytes) and steroid synthesis (leydig)
- Synthesizes cholesterol and fatty acids and lipids
- Have enzymes for detox of lipid soluble drugs
- Sequesters calcium in cytosol (SR in skeletal m)
146
Which organelle is prominent in alcoholics or drug addicts?
sER
147
Rough endoplasmic reticulum
- Membrane contains ribosomes on cytoplasmic side
- Prominent in protein secreting cells (ergastoplasm)
- Adds post-translation modifications to newly synthesized protein destined for secretion, lysosomes, and plasma membrane (for stability)
148
Which organelle is prominent in cells that specialize in lipid metabolism and steroid synthesis?
sER
149
Which organelles is prominent in protein secreting cells?
rER, Golgi apparatus
150
Ribosomes are directed to the rER membrane by the ___ on the growing polypeptide chain.
Signal peptide
151
Golgi Apparatus
Functions in protein packaging, concentration, and sorting
Has functional polarity: convex (cis) surface receives secretory proteins from rER and concave (trans) side is where vesicles exit
152
Golgi apparatus compartments
1. cis face
2. medial
3. trans face
4. trans Golgi network (TGN)
153
Trans Golgi network (TGN)
Where sorting of proteins occurs (lysosomes, plasma membrane, and constitutive [continuous] or regulated secretion)
154
What are the 3 types of coated vesicles?
Clathrin-coated, coatomer-coated, and caveolae
155
Functions of clathrin-coated vesicles
Transport of newly synthesized proteins from TGN to lysosomes, granules for regulated secretion, and formation of vesicles in receptor-mediated endocytosis
156
Morphology of clathrin-coated vesicles
Clathrin triskelion (3-legged structure made of 3 large and 3 small polypeptide chains), associates to form polyhedral cage network around vesicle
157
Receptor-mediated endocytosis
Receptor coated pits containing clathrin invaginate to form clathrin-coated vesicles
Vesicles lose clathrin coat and fuse/mature into an endosome
158
Coatomer-coated vesicles
Covered with coatomer proteins I or II that transport to/away from Golgi
COP I - retrograde transport: from Golgi to rER (donating membrane back to ER)
COP II - anterograde transport: rER to Golgi
159
___ donates membrane back to the endoplasmic reticulum.
COP I
160
___ transport material to and from the Golgi.
Coatomer-coated vesicles
161
Caveolae
- Form due to lipid composition of membranes
- Made of caveolin
- Function in clathrin-independent endocytosis and transcytosis
- In walls of blood vessels and in smooth muscle, help to concentrate calcium
162
Pinocytosis
Ingestion of fluids and solutes via small
vesicles
Includes receptor-mediated endocytosis
163
Endosomes
Vesicles associated with endocytosis
164
What are the 2 types of endocytosis?
Pinocytosis and phagocytosis
165
Pinocytosis is a clathrin-dependent form of endocytosis. T/F
False, pinocytosis can be clathrin-independent (involves caveolin-coated vesicles) or clathrin-dependent (receptor-mediated endocytosis)
166
Receptor-mediated endocytosis is a clathrin-dependent form of pinocytosis. T/F
True
167
Phagocytosis
Ingestion of large particles in phagosomes, performed by specialized cells mostly from monocytes
168
Phagosomes
Vesicles formed by phagocytosis, fuse with lysosomes to degrade phagocytized particles
169
Phagocytosis process
Phagocytes have receptors (Fc receptors) that recognize the surface of the foreign substance and ingest it by zippering the membrane around it
170
Lysosomes
Contain acid hydrolases (enzymes) with internal pH of 4.7 (maintained by proton pump), degrades endocytosed material and cellular material
171
Lysosomal acid hydrolases are synthesized in the ___ and targeted to the lysosomal compartment with the addition of ___ to the lysosomal protein in the ___.
rER, mannose-6-phosphate (M6P), trans Golgi network (TGN)
172
COP I transports from ___ to ___, while COP II transports from ___ to ___.
Golgi, rER
| rER, Golgi
173
Exocytosis
Fusion of vesicles with plasma membrane
174
What are the two secretory pathways leading to exocytosis?
Constitutive pathway and regulated secretory pathway
175
Constitutive secretion
Continuous, unregulated delivery to membrane (collagen)
176
Regulated secretion
In specialized cells, stored near membrane, needs a signal for release, calcium dependent
177
Mitochondria can be visualized with a light microscope. T/F
True
178
Mitochondria components
1. Outer membrane
- -porins and receptors
2. Intermembrane space
- -like cytoplasm, has kinases and cytochrome c
3. inner membrane
- -cristae, ATP synthases, cardiolipin, cellular respiration enzymes, and special transport proteins
4. Matrix space
- -Matrix granules (bind cations), Krebs cycle enzymes, beta-oxidation enzymes, DNA, tRNA, ribosomes
179
The ___ of the mitochondria has the highest protein concentration than any membrane of the cell.
Inner membrane
180
The thin folds of inner membrane that project into the interior of the mitochondria are called ___.
Cristae
181
Cardiolipin
Phospholipoprotein that makes the inner membrane impermeable to ions
182
Mitochondrial production of ATP
Reactions of the matrix space
- -conversion of pyruvate and fatty acids into acetyl CoA
- -acetyl CoA enters the Krebs cycle and NADH and FADH2 are produced
Reactions on the inner membrane
- -electrons from NADH and FADH2 are passed down the respiratory or electron transport chain causing protons (H+) to be pumped across the membrane from the matrix into the intermembrane space generating an electrochemical proton gradient across the inner membrane
- -the gradient drives protons back through the ATP synthase complex causing ATP synthase to add a phosphate to ADP forming ATP
183
Mitochondria has their own DNA, ribosomes, tRNA, and mRNA. T/F
True
184
Mitochondria have ___ in the matrix space that bind cations and regulate / localize ion concentrations.
Matrix granules
185
Mitochondrial apoptosis
Release cytochrome c from the intermembrane space into the cytoplasm which activates proteolytic enzymes in the caspase cascade
186
In ___, mitochondria are used to produce heat.
Brown fat cells
187
Peroxisomes
- -Beta oxidation of fatty acids into acetyl CoA
- -Contain oxidative enzymes that produce H2O2
- -Catalase converts H2O2 into water and oxygen
- -detox in liver and kidney cells (in sER)
- -Needed for myelin formation
188
What differentiates organelles and inclusions?
Inclusions are generally inactive
189
Glycogen morphology
PAS stain
| EM - rosettes (glycogen granules covered by enzyme layer)
190
Glycogen location
All cells, but commonly liver and muscle
191
Lipid morphology
Light microscope - round, clear vacuoles
If fixed with osmium tetroxide - black sphere
EM - surrounded by mitochondria
192
Lipid location
Adipocytes abundant in liver and steroid secreting cells
193
Lipofuscin
Left over yellow-brown pigment from lysosomes
194
Lipofuscin location
In cells with long life span, nerve and cardiac muscle
195
The age pigment refers to ___.
Lipofuscin
196
Hemosiderin
Byproduct of hemoglobin
197
Hemosiderin location
In macrophages of spleen, bone marrow, and liver where old RBCs are degraded
198
Melanin
Inserted over top of nucleus, protects nuclei from UV radiation
Found in keratinocytes, pigment cells of retina, and some nerve cells of brain
199
Crystals
Precipitation found in steroid producing cells
| Leydig cells and Sertoli cells of testis
200
The least common form of inclusion is ___.
Crystals
201
Necrosis
Due to injury or disease processes, associated with inflammation and tissue deterioration
Cell swells, chromatin clump, organelles fuse, cell lyzes, macrophage phagocytizes
202
Apoptosis
Programmed cell death
Cell volume decreases, organelles remain intact and move to blebs in membrane, cell breaks into membrane bound globules that are phagocytized
203
Cell death: ___ occurs to single cells while ___ occurs to groups of neighboring cells.
Apoptosis, necrosis
204
In apoptosis, the cell size ___ while in necrosis the cell ___.
Decreases, swells
205
Only apoptosis has blebs in cell membrane, not necrosis. T/F
False, blebbing occurs in necrosis as well, but the organelles don't localize in the blebs to break up into membrane-bound globules
206
The mechanism of apoptosis utilizes caspases in both extrinsic and intrinsic pathways. T/F
True
207
Procaspase activation and caspase cascade
Signal (intracellular or extracellular) activates a procaspase, which activates other procaspases leading to amplification of active caspases, which digest key proteins leading to cell death
208
___ cause the caspase cascade in the extrinsic pathway of activation of apoptosis.
Lymphocytes
209
___ causes the caspase cascade in the intrinsic pathway of activation of apoptosis.
Cytochrome c
210
The caspase cascade is caused by cytochrome c in the ___ pathway of activation of apoptosis, while lymphocytes causes it in the ___ pathway.
Intrinsic, extrinsic
211
Biological processes where apoptosis play an essential role
```
Development:
--correct # and spacing of neurons
--middle ear space
--vaginal opening
--webs of fingers/toes
--correct cell #
Adults
--mammary glands and uterus before/after pregnancy
--uterus during menstrual cycle
--elimination of viral/transformed cells
--changes in liver after drug use
--size of organs after trauma
```
212
Ergastroplasm
Area of cytoplasm that is stained basophilic in protein secreting cells for the RNA-rich ribosomes
High concentration of rER
213
Zymogen granules
Pink stain (H&E) of secretory granules of enzymes located near lumen
214
What is the function of early endosomes?
Sorting of ligand-receptors of endocytosis
215
Early endosomes
A non-lysosomal compartment that maintains an acidic environment in which ligands are dissociated from receptors
