TOPNOTCH MEDICAL BOARD PREP HISTOLOGY BY ALVIN VIBAR, MD
For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/
This handout is only valid for the Sept 2020 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.
SIMPLE EPITHELIUM
HISTOLOGY • Lined by single layer of cells
By Alvin Vibar, MD • According to cell shape:
Annotated by: Ryuichi Nakamura, MD o Simple squamous
§ Single layer of flat cells
TOPIC PAGE § Endothelium of blood vessels
§ Mesothelium of body cavities
Epithelium 130
§ Parietal layer of Bowman capsule
Skin 133
§ Alveoli of Lung
Connective Tissue and Bone 133
§ Corneal Endothelium
Muscle and Blood Vessels 136 § Well – adapted for exchange, lubrication and filtration
Respiratory System 137 purposes
Gastrointestinal System 138 o Simple cuboidal
Excretory System 142 § Single layer of cuboidal cells
Nervous System 143 § tubules of kidneys
Endocrine System 144 § GERMINAL EPITH of OVARY
Reproductive System 145 o Simple columnar
The Special Senses 145 § single layer of tall, columnar cells
§ lining epithelium of intestines
I. EPITHELIAL TISSUE
GUIDE QUESTION
Which of the following statements is CORRECT about the Epithelial
tissue?
A. It is highly vascular
B. It has abundant intercellular substance
C. It has regenerative capacity
D. All cells rest on the basement membrane
Simple Squamous Simple Cuboidal Simple Columnar
CHARACTERISTICS: Parietal Layer of Bowman
• Formed by epithelial cells Mescher AL. 2016. Junqueira’s Basic Histology Text and Atlas. 12th ed. McGraw Hill
• Cells are closely adherent to each other GUIDE QUESTIONS
• Cells are extremely cohesive The layer of cells that lines the outer surface of the lungs can be irritated
• AVASCULAR tissues by inhaled asbestos particles. Which of the following is the cell layer
• Provided with a Basement membrane or Basal lamina being described?
• Maybe derived from the three / 3 germ layers: A. Simple squamous – mesothelium
B. Simple squamous – endothelium
o Ectoderm C. Transitional epithelium
§ epidermis of skin, epithelium of cornea D. Simple cuboidal epithelium
§ skin (epidermis), lining of oral and anal canals, CNS and E. Simple columnar epithelium
neural crest derivatives
Asbestos Inhalation
o Mesoderm • Asbestos – A complex silicate in the form of needle-like fibers
§ lining epithelium of kidneys, male & female reproductive • Chronic exposure leads to fibrotic lesions initially occurring at the
tracts subpleural zone of the lower lung lobes.
§ connective tissues (bones, cartilages, muscles), CVS, blood, • Predisposes to mesotheliomas of the pleura and of the peritoneum –
lining of body cavities, Urogenital system may develop after a latent period of more than 20 years after chronic
o Endoderm industrial exposure; hence, it usually manifests in the elderly
12-132 Young B. et al. Wheater’s Basic Pathology. 5th ed. 2011
§ lining epithelium of gastro-intestinal tracts Dr. Nakamura
§ epithelium of GIT and respiratory system Corneal endothelium is an example of what type of Epithelium?
✔GUIDE QUESTION A. Transitional
B. Stratified
Bones, Muscles and Cartilages are derived from what germ layer?
A. Ectoderm C. Endoderm C. Pseudostratified
B. Epiderm D. Mesoderm D. Simple
Lining of Lens is an example of what type of Epithelium?
A. Stratified squamous
EPITHELIUM CLASSIFICATION - Covering or Gland B. Simple columnar
C. Simple squamous
D. Simple cuboidal
COVERING / SURFACE EPITHELIUM
The Lens
• – membranous layer that covers the external / internal surfaces • Composed of highly modified epithelial cells and anucleate fibers
of the body packed with proteins called crystallins
o Based on number of cell layer/s – 4 subtypes: • Derived from the ectodermal lens pit overlying the embryonic optic
1. Simple vesicle
2. Stratified • Anterior surface is lined with a single layer of cuboidal epithelial cells
12-413 Young B. Wheater’s Functional Histology. 6th ed. 2014
3. Pseudostratified Dr. Nakamura
4. Transitional Which of the following is a characteristic typical of Simple
epithelium?
✔GUIDE QUESTIONS A. All the cells border an open lumen
Type of epithelium wherein the number of cell layers varies B. All the cells function to prevent abrasion
according to the functional state of the organ: C. All the cells rest on a basal lamina
A. Simple C. Stratified D. All the cells are joined by zonula occludens
B. Transitional D. Pseudostratified E. All the cells have microvilli
Simple squamous epithelium is prevalent throughout the body and
organ systems. Which of the following is a primary function of this
type of epithelium?
A. Secretion
B. Lubrication
C. Absorption
D. Protection
E. Excretion
TOPNOTCH MEDICAL BOARD PREP HISTOLOGY BY ALVIN VIBAR, MD Page 130 of 148
For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/
This handout is only valid for the Sept 2020 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.
, TOPNOTCH MEDICAL BOARD PREP HISTOLOGY BY ALVIN VIBAR, MD
For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/
This handout is only valid for the Sept 2020 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.
PSEUDOSTRATIFIED EPITHELIUM
• Modification of simple epithelium
• All cells are in contact with the basal lamina but NOT all of them
reach the apical surface
• Cell shapes are variable
• False stratification
• Respiratory Epithelium:
o Pseudostratified Columnar Ciliated Epithelium with Goblet
Cells
GUIDE QUESTION
What organ system contains Transitional epithelium?
A. Cardiovascular C. Nervous
B. Gastrointestinal D. Urinary
TRANSITIONAL EPITHELIUM
Basement membrane
Mescher AL. 2016. Junqueira’s Basic Histology Text and Atlas. 12th ed. McGraw Hill • Modification of Stratified epithelium
• The number of cell layers varies with the functional state of the
STRATIFIED EPITHELIUM organ
• Stratified Epithelium • Uroepithelium
o Lined by several layers of cells o Lining epithelium of excretory passages of Urinary system
o Well adapted for protective / barrier purposes
• Stratified squamous
o Cornified: epidermis
o Non- cornified (shown in picture below): esophagus, vagina,
anal canal, cornea (external)
Young B et al. 2014.Wheater’s Functional Histology Text and Colour. Elsevier Ltd
Fantastic Rare Surface Epithelium and Where to Find Them:
Pseudostratified Columnar – Conducting respiratory passages (with
cilia), epididymis, vas deferens (with stereocilia)
Non-cornified Stratified Sq Respiratory Epithelium Stratified Cuboidal and Stratified Columnar – Excretory pancreatic
Eroschenko VP. 2013. diFiore’s Atlas of Histology with Functional Relations. Lippincott Williams & Wilkin ducts, salivary glands, sweat glands
GUIDE QUESTION Transitional epithelium – Urinary tract (renal calyces up to bladder);
dome-shaped when contracted, squamous when stretched
Respiratory epithelium is:
Microvilli or cilia?
A. Pseudostratified columnar ciliated with Goblet cell
If it’s for absorption, microvilli;
B. Pseudostratified columnar ciliated without Goblet cell
If it’s for movement, cilia.
C. Stratified squamous non-cornified Dr. Nakamura
D. Simple squamous
GLANDULAR EPITHELIUM
EXOCRINE GLANDS According to Structure
• May be unicellular or multicellular; 1. Unbranched simple tubular – e.g. Intestinal and rectal glands (Crypts of Lieberkuhn)
multicellular glands contain a secretory
portion and a ductal portion
• May be classified according to either
structure or discharge process
Unbranched simple tubular Intestinal epithelium
Eroschenko VP. 2013. diFiore’s Atlas of Histology with Functional Relations. Lippincott Williams & Wilkin
2. Branched simple tubular – e.g. Gastric glands
Branched simple tubular structure Gastric epithelium
Eroschenko VP. 2013. diFiore’s Atlas of Histology with Functional Relations. Lippincott Williams & Wilkin
TOPNOTCH MEDICAL BOARD PREP HISTOLOGY BY ALVIN VIBAR, MD Page 131 of 148
For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/
This handout is only valid for the Sept 2020 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.
, TOPNOTCH MEDICAL BOARD PREP HISTOLOGY BY ALVIN VIBAR, MD
For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/
This handout is only valid for the Sept 2020 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.
3. Coiled tubular – e.g. Sweat glands
Coiled tubular gland structure Sweat gland
Eroschenko VP. 2013. diFiore’s Atlas of Histology with Functional Relations. Lippincott Williams & Wilkin
4. Compound acinar – e.g. Mammary glands
Compound acinar gland structure Mammary gland
Eroschenko VP. 2013. diFiore’s Atlas of Histology with Functional Relations. Lippincott Williams & Wilkin
5. Compound tubuloacinar – e.g. Salivary glands
Compound tubuloacinar gland structure Salivary Gland
Eroschenko VP. 2013. diFiore’s Atlas of Histology with Functional Relations. Lippincott Williams & Wilkin
According to discharge process:
1. Merocrine – releases secretions by exocytosis without giving up any intracellular
components; e.g. sweat glands
2. Holocrine – cells themselves are the secretory product e.g. sebaceous glands
ENDOCRINE GLANDS
• No ducts; directly secrete products into
the bloodstream (highly vascularized)
• Found in the digestive tract as individual
enteroendocrine cells, in the pancreas as
pancreatic islets, and in the pituitary,
thyroid, and adrenal glands
Pancreatic islets
Eroschenko VP. 2013. diFiore’s Atlas of Histology with Functional Relations. Lippincott Williams & Wilkin
GUIDE QUESTIONS CLINICAL CORRELATE METAPLASIA
Type of epithelium well-adapted for exchange of substances METAPLASIA
between two sides: • Transformation of one tissue to another type
A. Simple C. Transitional • A stratified squamous epithelium may replace other
B. Pseudostratified D. Stratified epithelial types in areas of chronic irritation
Microvilli are essential components of epithelial cells of the small MALIGNANT AND BENIGN GROWTHS
intestine. Which of the following functions would be defective • CARCINOMA – a malignant neoplasm, an abnormal or
resulting from a lack of microvilli on epithelia? uncontrolled growth made up of epithelial cells; ARISE
A. Stretching D. Secretion FROM SURFACE EPITHELIA
B. Movement E. Absorption • Stratified squamous is most likely to undergo malignant
C. Protection
change producing SQUAMOUS CELL CARCINOMA
A 40 y/o man has a history of smoking. He complains of mucus • The glands of the body may also undergo neoplastic changes
accumulation and constant cough. A biopsy reveals that the epithelial • ADENOMA – a benign epithelial growth with glandular
lining of the tracheal lumen is stratified squamous epithelium. Which of morphology
the following terms describes the process of change to another
epithelial type?
• ADENOCARCINOMA – malignant growth; ARISE FROM
A. Metastasis C. Metaplasia GLANDS
B. Neoplasia D. Hyperplasia GUIDE QUESTION
Junctions are essential in maintaining the close association of the cells
within the epidermis. Which of the following junctions is important
in maintaining cell adherence in all layers of the epidermis?
A. Gap junctions C. Zonula occludens
B. Zonula adherens D. Macula adherens
TOPNOTCH MEDICAL BOARD PREP HISTOLOGY BY ALVIN VIBAR, MD Page 132 of 148
For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/
This handout is only valid for the Sept 2020 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.
For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/
This handout is only valid for the Sept 2020 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.
SIMPLE EPITHELIUM
HISTOLOGY • Lined by single layer of cells
By Alvin Vibar, MD • According to cell shape:
Annotated by: Ryuichi Nakamura, MD o Simple squamous
§ Single layer of flat cells
TOPIC PAGE § Endothelium of blood vessels
§ Mesothelium of body cavities
Epithelium 130
§ Parietal layer of Bowman capsule
Skin 133
§ Alveoli of Lung
Connective Tissue and Bone 133
§ Corneal Endothelium
Muscle and Blood Vessels 136 § Well – adapted for exchange, lubrication and filtration
Respiratory System 137 purposes
Gastrointestinal System 138 o Simple cuboidal
Excretory System 142 § Single layer of cuboidal cells
Nervous System 143 § tubules of kidneys
Endocrine System 144 § GERMINAL EPITH of OVARY
Reproductive System 145 o Simple columnar
The Special Senses 145 § single layer of tall, columnar cells
§ lining epithelium of intestines
I. EPITHELIAL TISSUE
GUIDE QUESTION
Which of the following statements is CORRECT about the Epithelial
tissue?
A. It is highly vascular
B. It has abundant intercellular substance
C. It has regenerative capacity
D. All cells rest on the basement membrane
Simple Squamous Simple Cuboidal Simple Columnar
CHARACTERISTICS: Parietal Layer of Bowman
• Formed by epithelial cells Mescher AL. 2016. Junqueira’s Basic Histology Text and Atlas. 12th ed. McGraw Hill
• Cells are closely adherent to each other GUIDE QUESTIONS
• Cells are extremely cohesive The layer of cells that lines the outer surface of the lungs can be irritated
• AVASCULAR tissues by inhaled asbestos particles. Which of the following is the cell layer
• Provided with a Basement membrane or Basal lamina being described?
• Maybe derived from the three / 3 germ layers: A. Simple squamous – mesothelium
B. Simple squamous – endothelium
o Ectoderm C. Transitional epithelium
§ epidermis of skin, epithelium of cornea D. Simple cuboidal epithelium
§ skin (epidermis), lining of oral and anal canals, CNS and E. Simple columnar epithelium
neural crest derivatives
Asbestos Inhalation
o Mesoderm • Asbestos – A complex silicate in the form of needle-like fibers
§ lining epithelium of kidneys, male & female reproductive • Chronic exposure leads to fibrotic lesions initially occurring at the
tracts subpleural zone of the lower lung lobes.
§ connective tissues (bones, cartilages, muscles), CVS, blood, • Predisposes to mesotheliomas of the pleura and of the peritoneum –
lining of body cavities, Urogenital system may develop after a latent period of more than 20 years after chronic
o Endoderm industrial exposure; hence, it usually manifests in the elderly
12-132 Young B. et al. Wheater’s Basic Pathology. 5th ed. 2011
§ lining epithelium of gastro-intestinal tracts Dr. Nakamura
§ epithelium of GIT and respiratory system Corneal endothelium is an example of what type of Epithelium?
✔GUIDE QUESTION A. Transitional
B. Stratified
Bones, Muscles and Cartilages are derived from what germ layer?
A. Ectoderm C. Endoderm C. Pseudostratified
B. Epiderm D. Mesoderm D. Simple
Lining of Lens is an example of what type of Epithelium?
A. Stratified squamous
EPITHELIUM CLASSIFICATION - Covering or Gland B. Simple columnar
C. Simple squamous
D. Simple cuboidal
COVERING / SURFACE EPITHELIUM
The Lens
• – membranous layer that covers the external / internal surfaces • Composed of highly modified epithelial cells and anucleate fibers
of the body packed with proteins called crystallins
o Based on number of cell layer/s – 4 subtypes: • Derived from the ectodermal lens pit overlying the embryonic optic
1. Simple vesicle
2. Stratified • Anterior surface is lined with a single layer of cuboidal epithelial cells
12-413 Young B. Wheater’s Functional Histology. 6th ed. 2014
3. Pseudostratified Dr. Nakamura
4. Transitional Which of the following is a characteristic typical of Simple
epithelium?
✔GUIDE QUESTIONS A. All the cells border an open lumen
Type of epithelium wherein the number of cell layers varies B. All the cells function to prevent abrasion
according to the functional state of the organ: C. All the cells rest on a basal lamina
A. Simple C. Stratified D. All the cells are joined by zonula occludens
B. Transitional D. Pseudostratified E. All the cells have microvilli
Simple squamous epithelium is prevalent throughout the body and
organ systems. Which of the following is a primary function of this
type of epithelium?
A. Secretion
B. Lubrication
C. Absorption
D. Protection
E. Excretion
TOPNOTCH MEDICAL BOARD PREP HISTOLOGY BY ALVIN VIBAR, MD Page 130 of 148
For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/
This handout is only valid for the Sept 2020 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.
, TOPNOTCH MEDICAL BOARD PREP HISTOLOGY BY ALVIN VIBAR, MD
For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/
This handout is only valid for the Sept 2020 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.
PSEUDOSTRATIFIED EPITHELIUM
• Modification of simple epithelium
• All cells are in contact with the basal lamina but NOT all of them
reach the apical surface
• Cell shapes are variable
• False stratification
• Respiratory Epithelium:
o Pseudostratified Columnar Ciliated Epithelium with Goblet
Cells
GUIDE QUESTION
What organ system contains Transitional epithelium?
A. Cardiovascular C. Nervous
B. Gastrointestinal D. Urinary
TRANSITIONAL EPITHELIUM
Basement membrane
Mescher AL. 2016. Junqueira’s Basic Histology Text and Atlas. 12th ed. McGraw Hill • Modification of Stratified epithelium
• The number of cell layers varies with the functional state of the
STRATIFIED EPITHELIUM organ
• Stratified Epithelium • Uroepithelium
o Lined by several layers of cells o Lining epithelium of excretory passages of Urinary system
o Well adapted for protective / barrier purposes
• Stratified squamous
o Cornified: epidermis
o Non- cornified (shown in picture below): esophagus, vagina,
anal canal, cornea (external)
Young B et al. 2014.Wheater’s Functional Histology Text and Colour. Elsevier Ltd
Fantastic Rare Surface Epithelium and Where to Find Them:
Pseudostratified Columnar – Conducting respiratory passages (with
cilia), epididymis, vas deferens (with stereocilia)
Non-cornified Stratified Sq Respiratory Epithelium Stratified Cuboidal and Stratified Columnar – Excretory pancreatic
Eroschenko VP. 2013. diFiore’s Atlas of Histology with Functional Relations. Lippincott Williams & Wilkin ducts, salivary glands, sweat glands
GUIDE QUESTION Transitional epithelium – Urinary tract (renal calyces up to bladder);
dome-shaped when contracted, squamous when stretched
Respiratory epithelium is:
Microvilli or cilia?
A. Pseudostratified columnar ciliated with Goblet cell
If it’s for absorption, microvilli;
B. Pseudostratified columnar ciliated without Goblet cell
If it’s for movement, cilia.
C. Stratified squamous non-cornified Dr. Nakamura
D. Simple squamous
GLANDULAR EPITHELIUM
EXOCRINE GLANDS According to Structure
• May be unicellular or multicellular; 1. Unbranched simple tubular – e.g. Intestinal and rectal glands (Crypts of Lieberkuhn)
multicellular glands contain a secretory
portion and a ductal portion
• May be classified according to either
structure or discharge process
Unbranched simple tubular Intestinal epithelium
Eroschenko VP. 2013. diFiore’s Atlas of Histology with Functional Relations. Lippincott Williams & Wilkin
2. Branched simple tubular – e.g. Gastric glands
Branched simple tubular structure Gastric epithelium
Eroschenko VP. 2013. diFiore’s Atlas of Histology with Functional Relations. Lippincott Williams & Wilkin
TOPNOTCH MEDICAL BOARD PREP HISTOLOGY BY ALVIN VIBAR, MD Page 131 of 148
For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/
This handout is only valid for the Sept 2020 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.
, TOPNOTCH MEDICAL BOARD PREP HISTOLOGY BY ALVIN VIBAR, MD
For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/
This handout is only valid for the Sept 2020 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.
3. Coiled tubular – e.g. Sweat glands
Coiled tubular gland structure Sweat gland
Eroschenko VP. 2013. diFiore’s Atlas of Histology with Functional Relations. Lippincott Williams & Wilkin
4. Compound acinar – e.g. Mammary glands
Compound acinar gland structure Mammary gland
Eroschenko VP. 2013. diFiore’s Atlas of Histology with Functional Relations. Lippincott Williams & Wilkin
5. Compound tubuloacinar – e.g. Salivary glands
Compound tubuloacinar gland structure Salivary Gland
Eroschenko VP. 2013. diFiore’s Atlas of Histology with Functional Relations. Lippincott Williams & Wilkin
According to discharge process:
1. Merocrine – releases secretions by exocytosis without giving up any intracellular
components; e.g. sweat glands
2. Holocrine – cells themselves are the secretory product e.g. sebaceous glands
ENDOCRINE GLANDS
• No ducts; directly secrete products into
the bloodstream (highly vascularized)
• Found in the digestive tract as individual
enteroendocrine cells, in the pancreas as
pancreatic islets, and in the pituitary,
thyroid, and adrenal glands
Pancreatic islets
Eroschenko VP. 2013. diFiore’s Atlas of Histology with Functional Relations. Lippincott Williams & Wilkin
GUIDE QUESTIONS CLINICAL CORRELATE METAPLASIA
Type of epithelium well-adapted for exchange of substances METAPLASIA
between two sides: • Transformation of one tissue to another type
A. Simple C. Transitional • A stratified squamous epithelium may replace other
B. Pseudostratified D. Stratified epithelial types in areas of chronic irritation
Microvilli are essential components of epithelial cells of the small MALIGNANT AND BENIGN GROWTHS
intestine. Which of the following functions would be defective • CARCINOMA – a malignant neoplasm, an abnormal or
resulting from a lack of microvilli on epithelia? uncontrolled growth made up of epithelial cells; ARISE
A. Stretching D. Secretion FROM SURFACE EPITHELIA
B. Movement E. Absorption • Stratified squamous is most likely to undergo malignant
C. Protection
change producing SQUAMOUS CELL CARCINOMA
A 40 y/o man has a history of smoking. He complains of mucus • The glands of the body may also undergo neoplastic changes
accumulation and constant cough. A biopsy reveals that the epithelial • ADENOMA – a benign epithelial growth with glandular
lining of the tracheal lumen is stratified squamous epithelium. Which of morphology
the following terms describes the process of change to another
epithelial type?
• ADENOCARCINOMA – malignant growth; ARISE FROM
A. Metastasis C. Metaplasia GLANDS
B. Neoplasia D. Hyperplasia GUIDE QUESTION
Junctions are essential in maintaining the close association of the cells
within the epidermis. Which of the following junctions is important
in maintaining cell adherence in all layers of the epidermis?
A. Gap junctions C. Zonula occludens
B. Zonula adherens D. Macula adherens
TOPNOTCH MEDICAL BOARD PREP HISTOLOGY BY ALVIN VIBAR, MD Page 132 of 148
For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/
This handout is only valid for the Sept 2020 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.
