1. Histology
Dr. Nichols Coronado HS

2. Hierarchy of the body
CELLS: the smallest living building blocks in the body.
TISSUES: groups of similar cells that join together for a particular function
ORGANS: groups of tissues that join together for a particular function

3. Cells are the living building blocks of the body
Cells come in many shapes and sizes that relate to their functions.
Cells are ALIVE

4. Cells group together to form TISSUES
Which two tissues are the same? Why?

5. Cells + stuff the cells secrete (proteins)
Tissues
Cells or
Cells + stuff the cells secrete (proteins)
cell
Protein
fiber
fluid, gel,
mineral
outside cell

6. Four major tissue categories by function
Nervous tissue (for communication)
Muscle tissue (for contraction)
Epithelial tissue (to cover organs or line hollows)
Connective tissue (between other tissues, or strength)
Figure 4.1

7. 24 specific tissue types. How many in each category? Are any familiar?
MT= MUSCLE TISSUE
ET= EPITHELIAL TISSUE
CT= CONNECTIVE TISSUE
NT= NERVOUS TISSUE
*very uncommon, no images shown in class

8. How does the body make all these tissues?
egg +
You! As one cell!
sperm
THREE EMBRYONIC TISSUES
Ectoderm
Mesoderm
Endoderm
You divide and form many copies of one cell type
Differentiation
During your development, your cells change into three embryonic tissues

9. Where did your adult tissues come from? Make a chart!
Mesoderm
Endoderm
16-day-old embryo
(dorsal surface view)
Epithelial
Tissue (from all three)
Nervous tissue
(from ectoderm)
Muscle and connective
tissue (mostly from
mesoderm)
Ectoderm
Where did your adult tissues come from? Make a chart!
Major tissue type
Derived from which embryonic tissue(s)? CT ET MT NT

10. What are the FOUR main tissue groups?
What are the THREE
embryonic tissues? .
What are the FOUR main tissue groups?

11. Which is a normal liver and which is pathological?

12. Fatty Liver Disease
Normal Liver Histology
You have to learn “normal” first

13. How do you name the Epithelial tissues?
1. Ask “How many layers does it have”?
Figure 4.2a
Stratified
Simple
Apical surface
Basal surface
(a) Classification based on number of cell layers.

14. How do you name the Epithelial tissues?
2. Ask “What are the shapes of the cells”?
Figure 4.2b
Squamous
Cuboidal
Columnar
(b) Classification based on cell shape.
transitional

15. Put the two names together into Epithelial Tissues (8 kinds)
Simple squamous ET
Simple cuboidal ET
Simple columnar ET
Pseudostratified columnar ET
Stratified squamous ET
Stratified cuboidal ET
Stratified columnar ET
Transitional ET
Simple arrangement of cells
Stratified arrangement
of cells

16. Overview of Epithelial Tissues
For each of the following types of epithelia, you must learn
To recognize the tissue
Full tissue name
Cell names
Locations in the body
Functions in the body

17. SIMPLE SQUAMOUS EPITHELIAL TISSUE
Description: Single layer of flattened
cells
Air sacs of
lung tissue
Function: Thinness of cells allows
dffusion of particles through the cells.
Cells covering organs secrete a
slippery fluid
Nuclei of
squamous
epithelial
cells
Location:
air sacs of lungs; lining of heart, lining blood vessels, lining
body cavity (serosae).
Photomicrograph: Simple squamous epithelium
forming part of the alveolar (air sac) walls (125x).
Figure 4.3a

18. Simple Squamous Epithelial Tissue
Location here: lining air pockets in lungs
Other places: lining blood vessels, covering organs or lining cavities in the body.
Cells: squamous epithelial cells
Function: a thin cell for gas diffusion, a slippery smooth surface
LOOK FOR: a very thin layer of cells covering or lining something.

19. Simple Squamous epithelial tissue…………..
is called Endothelium when found lining of blood vessels and heart
is called Mesothelium when found lining the inside of the body wall

20. urine (b) SIMPLE CUBOIDAL EPITHELIAL TISSUE
Description: Single layer of
cubelike cells with large,
spherical central nuclei.
cuboidal
epithelial
cell
Function: Secretion and
Absorption (such a when
making urine.
urine
Basement
membrane
Location: ex. Kidney TUBES
Surrounding urine.
Connective
tissue
Photomicrograph: Simple cuboidal
epithelium in kidney tubules (430x).
Figure 4.3b

21. Thyroid hormone (b) SIMPLE COLUMNAR EPITHELIAL TISSUE
Description: Single layer of
cubelike cells with large,
spherical central nuclei.
Simple
cuboidal
epithelial
cells
Function: Secretion and
Absorption (such a when
making THYOID HORMONE.
Basement
membrane
Thyroid hormone
Location: covering ball of
Thyroid hormone in thyroid gland
Connective
tissue
Photomicrograph: Simple cuboidal
epithelium in kidney tubules (430x).
Figure 4.3b

22. Simple cuboidal epithelial tissue, wraps the thyroid hormone into small bags in the thyroid gland
Analogy:
As if shapes on the
Soccer balls were
cells, and inside the
ball is thyroid
hormone

23. Simple Cuboidal Epithelial Tissue
Locations : forming ducts in kidney and of forming follicles (bags) of thyroid hormone.
Cells: cuboidal epithelial cells
Function:
Absorbs and secretes fluids
LOOK FOR: a single layer of cube shaped cells making up part of an organ.

24. food (c) SIMPLE COLUMNAR EPITHELIAL TISSUE
Description: Single layer of tall cells
Most have microvilli. Some cells
may release mucous (Goblet cells).
Simple
columnar
epithelial
cell
food
Function: Absorption; secretion of
mucus, enzymes, and other substances;
Location: lines most of
the digestive tract (stomach to anal canal),
gallbladder, and excretory ducts of some
glands;
Basement
membrane
Photomicrograph: Simple columnar epithelium
of the stomach mucosa (860X).
Figure 4.3c

25. Simple Columnar Epithelial Tissue
Location here: lines intestine
Cells: columnar epithelial cells, (and goblet cells)
Function: absorbs nutrients (goblet cells release mucous)
Specializations: microvilli
LOOK FOR: a single layer of column shaped cells on a wavy surface.

26. (d) PSEUDOSTRATIFIED CILIATED COLUMNAR EPITHELIAL TISSUE
Description: Single layer of cells of
differing heights, some not reaching
the free surface; nuclei seen at
different levels; may contain mucus-
secreting cells and bear cilia.
Cilia
Mucus of
mucous cell
Pseudo-
stratified
epithelial
layer
Function: Secretion, particularly of
mucus; propulsion of mucus by
ciliary action.
Location: ciliated variety lines
the trachea, most of the upper
respiratory tract.
Basement
membrane
Photomicrograph: Pseudostratified ciliated
columnar epithelium lining the human trachea (570x).
Trachea
Figure 4.3d

27. Pseudostratified columnar epithelial tissue
Location: lines trachea (windpipe)
Cells: columnar epithelial cells, (and goblet cells)
Function: move mucous up throat with cilia (goblet cells make mucous)
Cell specializations: cilia
LOOK FOR: what looks like a double layer of column shaped cells with a fringed edge.

28. (e) NON KERATINIZED STRATIFIED SQUAMOUS EPITHELIAL TISSUE
Description: Thick membrane
composed of several cell layers;
Of a variety of shapes. Top layer
Of cells are SQUAMOUS.
Stratified
squamous
epithelium
Function: Protects underlying
tissues in areas subjected to abrasion.
Nuclei
Location: Nonkeratinized type forms
the moist linings of the esophagus,
mouth, and vagina;
Basement
membrane
Connective
tissue
Photomicrograph: Stratified squamous epithelium
lining the esophagus (285x).
Figure 4.3e

29. (e) KERATINIZED STRATIFIED SQUAMOUS EPITHELIAL TISSUE
Description: Thick membrane
composed of several cell layers;
Of a variety of shapes. Top layer
Of cells are SQUAMOUS. WITH LAYER
OF EXFOLIATING SKIN.
Stratified
squamous
epithelium
Function: Protects underlying
tissues in areas subjected to abrasion.
Location: keratinized variety
forms the epidermis of the skin, a dry
membrane.
Connective
tissue
Photomicrograph: Stratified squamous epithelium
lining the esophagus (285x).
Figure 4.3e

30. Stratified Squamous Epithelial Tissue
Location here: lining esophagus
Function: covering and lining entrances to body to resist pathogens and abrasion
Cells: squamous epithelial cells
Specializations: desmosomes, tight junctions, keratin
LOOK FOR: many layers of cells

31. Stratified Cuboidal Epithelial Tissue
Sweat gland
Cuboidal epithelial cells 31

32. Stratified Cuboidal Epithelial Tissue
Location here: forming sweat glands in skin
Function: secretes sweat onto skin surface
Cells: cuboidal epithelial cells (blue cubes) arranged in circle they become a sweat gland. (red circle)
LOOK FOR: the round sweat glands with more than one layer of cube shaped cells.

33. Stratified Columnar epithelial tissue
Cells: columnar epithelial cells
Location: lining pharynx, male urethra
NO IMAGE

34. (f) TRANSITIONAL EPITHELIAL TISSUE
Description: Resembles both
stratified squamous and stratified
cuboidal; basal cells cuboidal or
columnar; surface cells dome
shaped or squamouslike, depending
on degree of organ stretch.
Transitional
epithelium
Function: Stretches readily and
permits distension of urinary organ
by contained urine.
Location: Lines the ureters, urinary
bladder, and part of the urethra.
Basement
membrane
Connective
tissue
Photomicrograph: Transitional epithelium lining the urinary
bladder, relaxed state (360X); note the bulbous, or rounded,
appearance of the cells at the surface; these cells flatten and
become elongated when the bladder is filled with urine.
Figure 4.3f

35. Transitional Epithelial Tissue
Location here: lining bladder
Function: allows stretching, cells slide over each other as bladder expands, then slide back into place as bladder empties
Cells: transitional epithelial cells arranged in layers.
Transitional “between, known shapes” ….kind of round.
LOOK FOR: layers of roundish cells

36. Compound duct structure
CUBOIDAL EPITHELIAL CELLS form glands!
The glands release oil, milk, sweat, saliva.
What do you think the number of cells in the gland depends on?
Figure 4.5
Compound duct structure
(duct branches)
SALIVARY
GLANDS
Surface epithelium
Duct
Secretory epithelium
Simple duct structure
(duct does not branch)
SWEAT GLANDS

37. EXOCRINE GLANDS
EXOCRINE GLANDS
Merocrine
Glands:
Release product
By exocytosis
into duct
(example sweat)
Holocrine
glands

38. EXOCRINE GLANDS EXOCRINE GLANDS . Merocrine glands Holocrine Glands:
Whole cell breaks
down and releases
Product plus protein
And lipids of cell wall
Example: oil, milk
Secretory
vesicles

39. Secretory vesicles containing mucous (a) (b) UNUSUAL EXOCRINE GLAND:
A single Goblet cell uses exocytosis to MUCOUS into trachea and intestines
Secretory
vesicles
containing
mucous
(a)
(b)
Figure 4.4