Midterm 1 Flashcards
(235 cards)
1
Q
What is the main stain used?
A
H&e. Hematoxylin and eosin
2
Q
What colour does Hematoxylin stain?
A
Purple
3
Q
What colour does eosin stain?
A
Pink
4
Q
What charge does hematoxylin have? What cellular component does hematoxylin stain?
A
Positively charged. Stains the nucleus
5
Q
What structures are stained by Hematoxylin?
A
Basophilic
6
Q
What colour does eosin stain?
A
Pink.
7
Q
What charge does eosin have? Is it acidic or basic?
A
Negative charge. Acidic
8
Q
What cellular component does eosin stain? What structure does eosin stain?
A
Cytoplasm. Acidophillic
9
Q
What solution are tissues treated with inorder to preserve them?
A
Formaldehyde. And then different concentrations of alcohol. If it is a fat it could get dissolved by the alcohol resulting in clear cells
10
Q
Which cells lend to appear when stained with h&e?
A
Collagen
11
Q
Who is the father of modern medicine?
A
Sir William outer (1849 - 1919)
12
Q
What are the 2 classifications of disease?
A
Environmental agents & genetics
13
Q
List some examples of environmental agents that could result in disease?
A
Carcinogens, radiation, PCB s, drugs, STDs, hygiene,tetracycline
14
Q
List some examples of genetic diseases?
A
Downs syndromes, kleinfilter syndrome, arthritis, some cancers
15
Q
What are the 4 aspects of a disease process?
A
Etiology → pathogenesis → morphological changes → clinical manifestation
16
Q
What does ethology mean?
A
What is the cause of the disease
17
Q
What is pathogenesis?
A
The mechanism of development
18
Q
What are morphological changes?
A
The structural alterations induced in cells, tissues and organs of the
body e.g. macroscopic (gross specimen) and microscopic
19
Q
What are clinical manifestations?
A
The functional consequences of the morphological changes.
20
Q
What is an idiopathic disease?
A
The disease is without an evident cause. Eg auto immune diseases
21
Q
What is a secondary disease?
A
The disease represents a complication or manifestation of an underlying condition
e.g. Nephropathy in diabetic patients.
22
Q
What is an acute disease?
A
Conditions that have a rapid onset
e.g. Appendicitis, periapical abscess
23
Q
What is a chronic release?
A
Conditions of insidious onset & have a
prolonged course lasting for months or
years e.g. pyogenic granuloma
24
Q
What are symptoms?
A
What the patient perceives to be wrong
e.g. fatigue, anxiety
25
What are signs
What the clinician perceives to be wrong
e.g. a lump or skin rash
26
What is a diagnosis?
Recognition of a disease by the signs
and symptoms
27
What is treatment?
Methods used to manage disease process
e.g. antibiotics for bacterial infectio
28
What is a prognosis
Probable outcome or likely course of the disease
29
What is a complication?
The 2 effects of a disease
30
What is remission
The conversion from active disease to quiescence (inactive state/ dormancy)
31
What is relapse?
The reappearance of signs & symptoms
32
What is histopathology?
The investigation and diagnosis of disease from the examination of tissues.
E.g. tumors
33
What is cytology
The investigation and diagnosis of disease from the examination of isolated
cells. e.g. Smear from the oral cavity
34
What is hematology?
The study of disorders of the cellular and coagulable components of blood.
E.g. Hemophilia (deficiency of factor VIII)
35
What is chemical pathology?
The study and diagnosis of diseases from the chemical changes (biochemical
processes) in the tissues and body fluids
e.g. Analysis of blood and urine
Increased sugar levels in diabetic patients due to lack of insulin
36
What is microbiology
The study of infectious diseases and the organisms responsible for them.
e.g. mycobacterium tuberculosis
37
What is immunology?
The study of the specific defense mechanisms of the body
e.g. Studying antibody levels
38
What are genetics?
The study of abnormal chromosomes and genes
39
What is toxicology
The study of the effects of known or suspected poisons/drug abuse
40
What is forensic pathology
The application of pathology to legal purposes (e.g. the investigation of
death in suspicious circumstances)
41
What is the protoplasm?
It is a living substance of the cell that possesses all vital products
made up of inorganic and organic molecules. It includes
cytoplasm and nucleus.
42
What is the cytoplasm
It is the jellylike, semi fluid matrix present between
the cell membrane and nuclear membrane.
43
What are living cell inclusions in the cytoplasm called?
Calla organelles
44
What are non living cell inclusions called?
ergastic substances and cytoskeletal elements.
45
What is the cytoplasm without cellular organelles called
Cytosol
46
In animals where is ATP produced?
Mitochondria
47
In plants where is ATP produced?
Chloroplasts
48
Where is ATP produced in bacteria?
Plasma membrane
49
What is the structure of the mitochondria
It is a spherical or rod shaped cell organelle. It has
two membranes. The outer membrane is smooth.
The inner membrane produces finger like
infoldings called cristae.
50
What is the mitochondrial county filled with?
The mitochondrial cavity is filled with a homogenous
granular mitochondrial matrix. Matrix of mitochondria
has enzymes for Krebs cycle, ATP synthesis, protein
and fat synthesis and contains DNA, RNA and 70s
Ribosomes.
51
What is a common name for the mitochondria
Powerhouse of the cell
52
What are the functions of the mitochondria
Mitochondria synthesise and store the energy rich
molecules ATP (Adenosine triphosphate) during aerobic
respiration. So, they are called “Power houses of the
cell”
53
What structures have their own DNA and 70s ribosomes?
DNA & plasmids
54
What kind of organelles are DNAand plasmids known as?
Semiautonomous organelles
55
Who is the mitochondrial DNA invented from? How many genes does it have?
It is inherited from the mother. Has 37 genes
56
Which organelles aid in the cells
synthesis, transport and secrete its products
Nucleus, Er, ribosomes, Golgi apparatus
57
What is the endoplasmic reticulum?
Endoplasmic reticulum is a network of
membrane bound tubular structures in the
cytoplasm.
58
The Er is spread amongst which organelles?
This membranous system extends from
plasma membrane up to nuclear membrane or
plasma membrane to cytoplasm or nuclear
membrane to cytoplasm. Endoplasmic
reticulum keeps on changing.
59
What is the listernae?
This is the Er existing as flattered sacs with unbranched tubules and oval vesicles
60
What are the 2 types of er?
RER, SER
61
Which ribosomes doesthe RER have on is surface?
80 S
62
Does the SER have ribosomes on its surface?
No
63
What are the functions ofthe er?
- Helps in intracellular protein formation and
transportation
- Helps in the formation of nuclear membrane and
Golgi complex
64
What is the Golgi apparatus?
Golgi complex has a group of curved,
flattened plate like compartments called
cisternae (4-10).
They stacked one above the other like
pancakes. The cisternae produce a network
of tubules. These tubules end in spherical
enzyme filled vesicles
65
How many faces does the Golgi apparatus hate?
2. The cis face & trans face
66
How many faces does the Golgi apparatus hate?
2. The cis face ( forming face), trans face (mature face)
67
What is another common name for the Golgi apparatus
Packaging centers
68
What are the functions of the Golgi apparatus?
1- They pack enzymes, proteins, carbohydrates
etc.in their vesicles
2- They produce Lysosomes
69
What is the lysosome
These are small single membrane bound
vesicles filled with hydrolytic enzymes.
Lysosomes are produced from Golgi
complex
70
How many types of lysosomes are there?
4
71
What are the different types oflysosomes?
Primary, secondary, residual & autolysosomes
72
What are primary lysosomes?
Newly produced
Lysosomes from Golgi bodies
73
What are secondary lysosomes?
Phagolysosome):
These are formed by the union of phagosome
and primary lysosome. It is also called
digestive vacuole
74
What are residual lysosomes?
These are secondary
Lysosomes left with undigested material
which is thrown out by exocytosis
75
What are autolysosome
These are formed by the union of primary
lysosome and worn out cell organelles
76
What is the common name for lysosomes?
Suicidal bags
77
What are the functions of lysosomes?
• They are concerned with intracellular
digestion
• They destroy old and non functional cells
which bear them. (Autolysis). So they are
called suicidal bags
• They break worn-out cells, damaged cells
and cell organelles to component molecules
for building new cell organelles. So they are
called “ Recycling centers”
78
Describe the lysosomic membrane?
The Lysosomal membrane is lipoproteinic. It has
stabilizers like cholesterol, cortisone, cortisol,
vitamin E which give stability to the membrane. So,
the enzymes do not digest the membrane.
79
What are peroxysomes
Found both in plant and animal cells. They takes part in
photorespiration in plant cells along with chloroplast and mitochondria. They also bring about fat metabolism in cells. They participate in oxidation of substrates resulting in the formation of hydrogen peroxide
80
What are microbodies?
What Lysosomes and Peroxysomes are known as
81
What are vacuoles?
Vacuoles are single membrane bound sac
like vesicles present in cytoplasm.
The plant cells have large v
82
What is the function of vacuoles?
•Storage vacuoles: These function like reservoirs.
83
Which organelles organelles do not have any
membranous covering?
Ribosomes and Centrosome
84
What are ribosomes?
•These are granular, nonmembranous particles present
in the cytoplasm, mitochondria and plastid
85
What are ribosome attached?
Rough ER and nuclear
membrane.
86
Which ribosomes do prokaryotes have ?
70s (50s + 30s) ribosomes in
cytoplasm.
87
Which ribosomes do eukaryotes have?
Eukaryotes have 80s (60s+40s) ribosomes in
cytoplasm and 70s (50s+30s) ribosomes in mitochondria.
88
What is the Svedberg unit?
Components of cell after centrifugation,
sediment or settle down at different speeds depending
upon their mass and size. The coefficient of
sedimentation is represented in Svedberg unit and
depicted as S.
89
What is the func. Of protein factories of the call
These are the sites of polypeptide or
protein synthesis
90
What are the funds. Of thecentrosome?
•They form asters and organize the formation
of spindle fibres during cell division.
•They are involved in the formation of cilia,
flagella and axial filament in sperms.
91
Which cells have A Centro some?
Animal cells. Plant cells don't have
92
What are centrioles?
Cylindrical structures found in thecentrosome
93
What is the structure ofthe centrioles µtubules?
The centrioles are arranged at right angles to one
another. Each centriole is made up of a whorl of
nine triplets of microtubules.
• These microtubules run parallel to one another.
The adjacent microtubules are connected by
proteinaceous strands
94
What is the cilia & flagella?
are hair-like micro-tubular organelles
projecting from the cell surface into the extracellular medium
and are concerned with cell motility.
95
Example of unicellular organism that uses cilia to swim?
Paramaecium and Euglena
96
Which multicellular organisms use cilia?
epithelial tissues) have cilia.
They beat and create a current in the fluid in order to move in a given direction
e.g. in the wind pipe (trachea) to push out the mucus and dust particles.
Reproductive cells as spores and gametes bear one, two or many cilia or
flagella for movement.
97
Which protein are cilia & flagella of ade
Both are made up of contractile protein
tubulin in the form of microtubules.
98
What is the arrangement of microtibules?
The arrangement of the microtubules is
• 9 + 2, that is, two central microtubules
surrounded by nine peripheral ones.
99
Where do cilia and flagella arise from?
Basal bodies
100
Difference between cilia & flagella
• Cilia are shorter and more numerous on
cells
• Flagella are longer and fewer (usually 1-3)
on cells
101
What is the cytoskeleton?
a structure that helps cells maintain their shape and internal
organization, and it also provides mechanical support that enables cells to
carry out essential functions like division and movement
102
Which protein do microfilaments have?
Actin
103
What protein do microtubules have?
Tubulin
104
What is atrophy?
Decreased cell size ↓
105
What is hypertrophy?
This is an increase in cell size ↑ increase in the cell: nucleus ratio
106
Give an example of hypertrophy
Cardiomyopathy
107
What is hyperplasia?
Increase in cell number
108
What is metaplasia?
Change from round cells to columnar cells
109
What is an example of Barretts metaplasia
GERD
110
What does GERD stand for?
Gastroeosophageal reflux disease
111
What is apoptosis?
Uncontrolled cell death. Reversible
112
What occurs in coagulate necrosis?
Loss of cellular architecture and coagulation
113
What causes coagulative necrosis?
Un-natural cell death. Which can be caused by hypoxia and ischemia
114
What are some examples of coagulative necrosis?
Myocardial infarction & kidney infarction
115
What happens in caseous necrosis?
Langhans giant cell is seen. Horseshoe shaped. Cheese-like structure in lungs. Necrotic areas lose cellular arrangement & architecture
116
In which disease can we see caseous necrosis
Tuberculosis
117
What is cell injury?
Cell injury is defined as the functional and morphologic effects of a variety of stresses due to the etiologic agents a cell encounters, resulting in changes in its internal and external environment.
118
What are some causes of cell injury
Oxygen deprivation due to hypoxia, ischemia
119
What are some physical agents that can cause cell injury?
- Mechanical Trauma e.g. sport activities
- Extremes of temperature
Eg; Burns / Freezing cold
- Sudden changes in atmospheric pressures
Eg; Decompression sickness
- Radiation
Eg; solar/nuclear/ therapeutic
- Electric shock
120
What are some chemical agents & drugs that can cause cell injury?
Poisons e.g. cyanide and arsenical compounds
• Environmental and air pollutants e.g. carbon monoxide smoke
• Insecticides and herbicides
• Industrial and occupational hazards
e.g. Occupational: e.g. glutaraldehyde saturation in laboratories
• Social stimuli
e.g. alcohol, tobacco, narcotic drugs
• Medicinal drugs
e.g. Oral contraceptives cause pigmentation of gums.
121
What are some infectious agents that can cause call injury ?
Bacteria, fungi, viruses, parasites
122
Immunologic reactions and cell injury
Anaphylactic reaction (severe allergic reaction) to Proteins e.g. Inj. B Complex Drugs e.g. Inj. Penicillin
- Autoimmune diseases
Rheumatoid Arthritis
Hashimoto’s Thyroiditis causes hypothyroidism
In the oral cavity – delayed eruption, poor periodontal health & altered tooth morphology
123
Explain how genetic rearrangements can cause cell injury
Conditions like; downs syndrome, and sickle cell anemia can cause cell injury
124
Explain how genetic rearrangements can cause cell injury
Conditions like; downs syndrome, and sickle cell anemia can cause cell injury
125
Explain how genetic rearrangements can cause cell injury
Conditions like; downs syndrome, and sickle cell anemia can cause cell injury
126
Explain how nutritional imbalance can cause cell injury
Protein calorie malnutrition
– Rickets
– Obesity
– Atherosclerosis
Prolonged Vit D deficiency
Protein energy malnutrition
Vegetarians have to take dietary supplements order to meet their nutritional requirements
127
Which intracellular systems are vulnerable to cell injury?
- Cell membranes :
Maintenance of the integrity is important to carry out the process of exchange.
- Mitochondria: ATP depletion
- Endoplasmic Reticulum: Improper protein production
- DNA: Disrupts the integrity of the genetic apparatus
128
Which intracellular systems are vulnerable to cell injury?
- Cell membranes :
Maintenance of the integrity is important to carry out the process of exchange.
- Mitochondria: ATP depletion
- Endoplasmic Reticulum: Improper protein production
- DNA: Disrupts the integrity of the genetic apparatus
129
Which intracellular systems are vulnerable to cell injury?
- Cell membranes :
Maintenance of the integrity is important to carry out the process of exchange.
- Mitochondria: ATP depletion
- Endoplasmic Reticulum: Improper protein production
- DNA: Disrupts the integrity of the genetic apparatus
130
What happens it the cell membrane gets injured?
Altered cell membrane permeability
• Damaged membranes lead to loss of fluid and electrolyte imbalance
• This results in swollen Endoplasmic reticulum (ER) and mitochondria (MT)
131
What is atrophy?
Decrease in the size of the cell, tissue or organ
132
What is hypertrophy?
Increase in the size of the organ or tissue due to the increase in the size of the cell
133
What is hypertrophy?
Increase in the size of the organ or tissue due to the increase in the size of the cell
134
What is hyperplasia?
Increase in the size of the organ or tissue due to the increase in the number of the cell
135
What is metaplasia?
Reversible transformation of one cell type to another
136
What are some adaptive morphological changes that occur?
Atrophy, hypertrophy,hyperplasia, metaplasia
137
What are some reversible morphological changes?
Adaptive changes, cellular swelling, fatty change
138
What are some irreversible morphological changes)
Apoptosis & necrosis
139
What is apoptosis?
Apoptosis is defined as ‘programmed cell death’ or ‘cell suicide’.
• Active process
• It is not accompanied with inflammation.
• Example: Ageing
140
How is apoptosis in physiologic conditions?
- During embryogenesis, organogenesis, metamorphosis
-Shedding of the endometrium during menstruation.
- aging
141
Apoptosis in paledomons
-Cell death produced by a variety of injurious stimuli
e.g. radiation
- Cell injury in certain viral diseases
e.g. Destruction of lymphocytes in AIDS
142
What is necrosis?
• Necrosis is untimely death of the cells due to uncontrolled external stimuli.
• Pathological and passive process.
• Leads to tissue damage and inflammation.
143
What are the differences between apoptosis & necrosis
-Necrosis is increase in cell volume and apoptosis is tell shrinkage
-loss of plasma membrane integrity in necrosis andplasma membrane blabbing in apoptosis
- leakage of cellular contents in necrosis and formation of apoptotic,bodies in apoptosis
- Enzymatic digestion of the cell. Necrosis
- Denaturation of intracellular proteins. Necrosis
144
What are the types of necrosis?
Coagulate, liquefactive, fat ,caseous
145
What are some examples of coagulate necrosis?
Myocardial Infarction is an example of coagulative necrosis due to ischemia (loss of blood supply)
146
What is liquefactive necrosis?
Characterized by digestion of the dead cells by lysosomal enzymes,
resulting in transformation of the tissue into a liquid viscous mass.
e.g. Brain infarct (hypoxia) or fungal infections.
147
What is another name for caseous necrosis?
Cheese like
148
What is caseous necrosis?
Form of Coagulative necrosis associated with some bacterial infections such as Tuberculosis. Has white cheesy material
149
What is fat necrosis?
Fat necrosis occurs only in adipose (fat) tissue,
usually in association with pancreatitis, which
releases numerous pancreatic lipases and
proteinases.
• Liberated fatty acids + calcium become saponified to
form calcium soaps, which appear as chalky white
deposits in the fatty tissue.
Fat Necrosis
Chalky white deposits represent areas of fat necrosis with
calcium soap formation (saponification) in the pancreas
Pancreatitis is inflammation of the pancreas
150
Where does fat necrosis occur?
Fat necrosis occurs only in adipose (fat) tissue,
usually in association with pancreatiti
151
What is commonly observed in fat necrosis?
Liberated fatty acids + calcium become saponified to
form calcium soaps, which appear as chalky white
deposits
152
What is an example of physiologic hypertrophy?
Skeletal muscle hypertrophy in athletes
Hypertrophy of smooth muscles of the pregnant uterus
153
What is an example ofpathologic hypertrophy?
Left ventricular hypertrophy in longstanding hypertension.
154
What is an example ofpathologic hypertrophy?
Left ventricular hypertrophy in longstanding hypertension.
155
What are examples of physiologic hyperplasia?
– Increase in number of smooth muscles
in the uterus due to normal increase in estrogens during pregnancy.
– Increase in number of glands due to normal increase in estrogens and
prolactin in the lactating breast.
156
What is an example of pathologic hyperplasia?
wound healing
157
What is an example of physiologic atrophy?
Thymus gland undergoes atrophy in childhood.
The uterus decreases in size shortly after parturition/child birth
158
Example of pathologic atrophy?
Pathologic atrophy depends on the underlying cause and can be local or generalized.
159
Example of pathologic atrophy?
Pathologic atrophy depends on the underlying cause and can be local or generalized.
160
What are some types of atrophy?
' Disuse atrophy (fractures)
- pressure
- inadequate nutrition
- loss of nerve supply (polio)
161
What is dysplasia?
Disordered Cellular Development’, often preceded or accompanied with metaplasia and hyperplasia.
• Dysplastic changes often occur due to chronic irritation or prolonged inflammation.
Irreversible
162
What are the 3 forms of cellular response?
Subcellular alterations, Intracellular accumulations, Pathologic calcification
163
What are subcellular alterations
Subcellular alterations are seen in cells that are exposed to sublethal or
Chronic stimuli and may not appear damaged on light microscopy. Can only be seen with an electron microscope
164
What are intracellular accumulations?
Intracellular accumulations of several substances, including proteins, lipids
and carbohydrates is associated with metabolic derangements
165
What are pathologic calcifications
deposition of calcium in areas of cell
death or normal tissue. Can be seen in a light microscope
166
What are the 3 groups intracellular adaptations are divided into?
a. Accumulation of constituents of normal cell metabolism produced in
excess e.g. accumulations of lipids (fatty change, cholesterol deposits),
proteins and carbohydrates.
b. Accumulation of abnormal substances produced as a result of
abnormal metabolism.
c Accumulation of pigments e g endogenous & exogenous pigme
167
Explain accumulation of lipids
Accumulation of lipids (free fatty acids) in the liver as it is the site for fat
metabolism.
e.g. Obesity and Diabetes Mellitus
168
Accumulation cholesterol
Accumulation of cholesterol in macrophages, converting them into foamy
macrophages.
e.g. Artherosclerosis
169
Accumulation of proteins
e.g. Excessive reabsorption of proteins in the kidney
170
Accumulation of glycogen
Diabetes mellitus
171
What are pigments?
Pigments are colored substances present in most living beings including
humans. There are 2 broad categories of pigments; endogenous and
exogenous.
172
What are endogenous pigments
either normal constituents of cells or
accumulate under special circumstances e.g. melanin
173
What is melanin
Endogenous pigment.
• Melanin is produced by cells called melanocytes (cells
present in the basal cell layer of the epithelium)
• It is a brown-black, non-haemoglobin-derived pigment
normally present in the hair, skin and mucosa.
174
What is tyrosinase?
Tyrosinase is the enzyme required to convert tyrosine to
melanin.
• E.g. Oral melanosis, excessive melanin deposition due to
hyperactivity of melanocytes.
Albinism, no melanin production due to absence of enzyme.
175
What is a melanoma
This is a breach of melanocytes into the basement membrane and connective tissue
176
What is hyper and hypo- pigmentation
Hyperpigmentation:
Excessive Production
Hypopigmentation:
Decreased Production or complete
absence
177
What is hemosiderin
Iron containing pigment
• Derived from breakdown of hemoglobin
• During disturbances in iron metabolism
• Granular or crystalline yellow brown
pigment
• Often seen in macrophages in bone marrow,
spleen and liver (lots of red cells and RBC
breakdown); also in macrophages in areas of
recent hemorrhage
• E.g. Anemia, excessive dietary intake
178
When rbc's rupture what are the I ways iron can be stored?
Ferritin ( soluble), hemosidrin (insoluble)
179
What are exogenous pigments?
pigments introduced into the body from outside such
as by inhalation, ingestion or inoculation.
180
What are inhaled pigments?
• The most inhaled substances are carbon or coal dust.
• Lung is the most affected organ.
• Occupational hazard e.g. coal miners
181
Ingested pigments?
Chronic ingestion of certain metals may produce pigmentation.
• E.g. lead poisoning creating blue line in a tooth
182
Injected pigments
In the process of tattooing where the pigment is taken up by
macrophages and lies permanently in the connective tissue.
• E.g. India Ink
183
Pathological calcifications can be divided into 2 types
A) metastatic: in healthy normal live tissue
B. Dystrophic: in necrotic issue
184
Is the epithelium vascular?
No its vascular, it gets its nutrition from the underlying connective tissue
185
What structures does the epithelium cover?
➢ Exterior body surfaces (such as skin)
➢ Line internal closed cavities (Such as vascular system, Pericardial
cavity, pleural cavity and peritoneal cavity).
➢ Body tubes that communicate with the exterior (gastrointestinal tract,
respiratory, and genitourinary tracts).
186
What are 2 other functions of epithelial tissue?
Epithelium also forms the secretory portion (parenchyma) of glands and
their ducts (Glandular Epithelium).
3- Specialized epithelial cells function as receptors for the special senses
(smell, taste, hearing, and vision).
187
What are the 3 germ layers epithelium is derived from?
1- ECTODERM: Oral and nasal mucosa, cornea, epidermis of the skin &
glands of the skin & the mammary glands.
2- ENDODERM: lining of the respiratory and GIT.
3- MESODERM: Endothelial lining of the circulatory system and the
mesothelium of the body cavity
Echo →meso» ends
188
What is the germ layer for the oral mucosa?
Ectoderm
189
What are the special names?
1. Endothelial (lining of the circulatory system ).
2. Mesothelium (lining of the internal body cavity).
190
What are characteristics of epithelium?
1. It is avascular tissues taking its blood supply from underlying
connective tissues.
2. They are closely packed and adhere to one another by specialized cell junctions.
3. The cells exhibits functional polarity through apical, a lateral, and a
basal domains.
4. Their basal surface is attached to an underlying basement membrane
191
What are tight junctions?
Seals the gap between epithelial cells
192
What are adheren's junctions?
Connects actin filament bundle in one all to another
193
What are des mesomes?
Connects intermediate filaments in one cell to another
194
What are gap junctions?
Allows the passage of water soluble molecules from cell to cell
195
What are hemidesmosome?
Anchors intermediate filaments in a cell to ECM
196
What is the basement membrane divided into?
Basal Latina and reticular Latina
197
Basal Latina is further divided into what?
Lamina Lucida and Lamina Densa. it can only be seen with an electron microscope
198
What is the main component of the basal Lamina?
Type 4 collagen
199
Reticular Latina describe?
Reticular lamina is formed by reticular fibers , as the name
suggests. The reticular lamina is usually thicker than the basal
lamina.
200
What are the functions of epithelium
•Protection (covers the body- line body cavities and body tubes)
•Absorption (Glandular Epithelium)
•Secretion (Glandular Epithelium)
•Sensory (Heat, Touch, Taste buds, Vision, Smelling, Hearing)
201
What 2 categories can epithelium be classified into?
Shape & number
202
How is it classified according to shape
• Squamous (When the width of the cell is greater than its height.)
• Cuboidal (When the width, depth & height are approximately the same)
• Columnar (When the height of the cell approximately exceeds the width).
203
How is it classified according to number
1) Simple (When it is one cell layer thick)
2) Pseudostratified
3) Stratified (When it has two or more cell layer)
• Squamous
• Cuboidal
• Columnar
• Transitional
204
Function and location of squamous epithelial cells
Blood vessels, allows materials to pass through by diffusion
205
Function & location of cuboidal cells
Kidney tubules, secretes & absorbs
206
Simple columnar epithelium function & location
Digestive tract
207
Pseudostratified ciliates columnar epithelium
Upper respiratory tract, trachea
208
Stratified squamous epithelium
Vagina, esophagus, mouth
209
Stratified cuboidal
Sweat gland, salivary glands, mammary glands
210
Transitional epithelium
Urinary bladder
211
What are the structures of the flagella?
Axoneme, central microtubules, dynein arms,,
212
What is oral epithelium
Oral epithelium forms the surface of the oral
mucosa that forms a barrier between the oral
environment and the deeper tissues
213
What germ layer is the oral epithelium derived from
Embryonic ectoderm
214
What type of epithelium makes the oral epithelium
It is stratified squamous epithelium and may or
may not be keratinized
215
Difference between parakeratinized&orthokeratinized
Parakeratinized Epithelium
• Pyknotic nuclei and other organelles may
remain in the keratinized layer.
Ortho-keratinized Epithelium
The keratinized layer do not have any nuclei
or organelles
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Keratinocytes are divided into what layers
• Basal cell layer (stratum basale)
• Prickle cell layer (stratum spinosum )
• Granular cell layer (stratum granulosum)
• Keratin layer (stratum corneum)
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Describe stratum basale
The cells are cuboidal or low columnar and
form a single layer resting on the basal lamina.
The basal cells show the maximum mitotic
activity
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What is the stratum germinativum layer
Cells in the basal layer plus initial cells in the spinosum layer
219
Describe stratum spinosum
They are several polyhedron shaped cell layers
with short cytoplasmic processes
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Stratum granulosum
• Are flat of three to five cells layers
• This layer is prominent in keratinized epithelium (and
absent in nonkeratinized epithelium)
• These cells have keratohyaline granules in their
cytoplasm
• Keratohyaline granules help to form the matrix of the
keratin fibres found in the superficial layer
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Describe stratum corneum
• Cells of stratum corneum are flat, devoid of nuclei
and full of keratin filament
• These cells are continuously being desquamated and
are replaced by epithelial cells that migrate from the
underlying layers.
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What are Non Keratinocyte cells of the Oral Epithelium
• Melanocytes
• Langerhans cells
• Merkel cells
• Inflammatory cells
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Where do melanocytes arise from
Melanocytes arise embryologically from the neural
crest, they are present between basal cells .
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What pigment arises from melanocytes
Melanin
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Where is the pigmentation seen
Accumulation of melanin gives rise to pigmentation
of the mucosa that is seen clinically most in the
region of gingiva followed by the buccal mucosa,
hard palate and tongue.
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What are langerhans cells
it is a dendritic cell seen above the basal layer
and oral epithelium.
• They are derived from the bone marrow.
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What langerhan cells do?
They recognize and process antigenic material
that enters the epithelium from the external
environment and present it to the T lymphocytes.
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What are Merkle cells
The Merkel cells are situated in the basal cells of
the oral epithelium and epidermis.
The Merkel cells are sensory and respond to
touch.
These cells may arise from division of an
epithelial cell (Keratinocytes) as they have some
tonofilaments and an occasional desmosome
linking them to adjacent cells.
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What are inflammatory cells
• Inflammatory cells may be seen in the oral mucosa.
• These are mainly lymphocytes, sometimes neutrophils and mast
cells.
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• These appear to be transient and are regarded as normal
components of the nonkeratinocyte population of the oral
epithelium.
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What do Merkle cells respond to?
Touch
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Where do Merle cells arise from
These cells may arise from division of an
epithelial cell (Keratinocytes) as they have some
tonofilaments and an occasional desmosome
linking them to adjacent cells.
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What are some examplesof inflammatory cells?
These are mainly lymphocytes, sometimes neutrophils and mast
cells
233
What are glands?
Glands are derivatives of surface epithelium.
• Consists of one or more cells that make and secrete a particular
product
• Cells from mother epithelium invaginate into the connective tissue
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beneath and thus develops the gland
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How does an exocrine gland develops?
connection between the mother exithelium and fetus persists s
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How does an endocrine gland form
If the connection obliterates, endocrine gland forms.
