Histology

1
Histology

• Chapter 3

2
Histology

• The study of tissues
• Tissues
• Groups of cells of common origin and function.
• Tissue types
• Epithelialcover body surfaces or a line a body
  cavity.
• Connectiveconnect, bind, support.
• Muscularcontractile tissues
• Nervousinitiates and transmits impulses

3
Epithelial Tissues

• Line body surfaces and cavities.
• Classification
• Layering Simple vs. Stratified
• Cell shape Squamous vs. Cuboidal vs. Columnar
• Rest on a basement membrane
• Layer of glycoprotein plus collagenous and
  reticular fibers

4
Simple Squamous Epithelium

• Simple
• All cell rest on the basement membrane
• Squamous
• Cells are flattened, usually with a protruding
  nucleus
• Examples
• Inner lining of blood vessels.
• Lining of pulmonary alveoli
• Lining of visceral organs and the body cavity.

Serosa of small intestine
5
Simple Squamous Epithelium Laboratory
ObservationsVan De Graff and Crawley
Photographic Atlas of Anatomy and Physiology
Morton Publishing
Aorta Cross section. Simple squamous epithelium
lines the blood vessel lumen. Note flattened
cells and protruding nuclei.
Pulmonary Alveoli Cells making up alveolar wall
are a single layer thick and some nuclei can be
seen protruding into the alveoli.
6
Simple Cuboidal Epithelium

• Cuboidal
• Cells are about as tall as deep as wide
• Round nuclei
• Cells are actually 6-sided
• Example
• Kidney tubules

7
Simple Cuboidal EpitheliumLaboratory
Observations
http//bioweb.wku.edu/faculty/Hoyt/Biol324old/
http//home.primus.com.au/royellis/ct5.jpg
Kidney Tubule sections. Note perfectly round
nuclei and cells as tall as they are wide.
Lumen
Nucleus
Basement Membrane
8
Simple Columnar Epithelium

• Columnar
• Cells taller than wide or deep
• Nuclei elongate in the direction of cell
  elongation
• Example
• Small intestine epithelium

9
Simple Columnar EpitheliumLaboratory
Observations
ttp//www.lab.anhb.uwa.edu.au/mb140/CorePages/Vasc
ular/Images/jej20he.jpg
h
histology.class.kmu.edu.tw/image/
photo02/skin/006-na1g.jpg
Small intestine Cells and nuclei elongate in same
plane Basement membrane
10
Pseudostratified Columnar Epithelium Laboratory
Observations

• Pseudostratified
• Nuclei appear to be at different levels
• In fact, all nuclei reach the basement membrane
• Note cilia and goblet cells
• Examples
• Trachea
• Bronchus

11
Stratified Squamous Epithelium

• Stratified
• Multilayered
• Only the lower-most layer of cells reaches the
  basement membrane
• Squamous
• The top layer of cells is flattened in the same
  plane as the tissue surface
• Nuclei, when present flattened in the same plane
  as the cell
• Examples
• Epidermis of skin
• Epithelial lining of the esophagus
• Epithelial lining of vagina

12
Stratified Squamous EpitheliumLaboratory
Observations
http//wwwpath.usuf2.usuhs.mil/surg_path/nlhist/pi
ctures/nl0026a.gif
http//histology.class.kmu.edu.tw/image/photo02/sk
in/014-na1g.jpg
Skin Basement Membrane Note flattening of cells
and nuclei near tissue surface.
Esophagus
13
Laboratory ObservationsEpithelial Tissues

• Simple Squamous
• Aorta cs (inner lining)
• Lung (alveoli)
• Simple Cuboidal
• Kidney (tubules)
• Simple Columnar
• Small intestine (inner epithelium)
• Uterine (fallopian) tube (ciliated inner
  epithelium)

• Pseudostratified
• Trachea (inner epithelium)
• Stratified Squamous
• Skin
• Esophagus

14
Connective Tissue

• Binds and supports other tissues and organs.
• Classification
• Fibrous Connective Tissue
• Loose Connective Tissue
• Abundant matrix (loose and flexible)
• Cells (e.g., fibroblasts)
• Fibers (collagenous, elastic, reticular)
• Dense connective tissue
• Fibers abundant (collagenous, elastic reticular)
• Cells (e.g., fibroblasts)
• Matrix (loose and flexible)
• Supportive Connective Tissue
• Cartilage
• Matrix (semisolid)
• Cells (e.g., chondrocytes) within lacunae
• Fibers (all 3 types)
• Bone
• Matrix with calcium phosphate deposition
• Cells (e.g., osteocytes) within lacunae

15
Fibrous Connective TissueLoose Connective
(Areolar) Tissue

• Collagenous and elastic fibers distributed in
  nonoriented manner
• Cells fibroblasts and mast cells (produce
  heparin)
• Attaches skin to muscles and surrounds blood
  vessels and nerves
• Provides flexibility and strength in any direction

16
Fibrous Connective TissueLoose Connective
(Adipose) Tissue

• Adipose
• Loose connective tissue with adipose cells
  modified for fat storage
• Energy storage, insulation, anchors and cushions
  organs, contributes to breast structure in
  females.

17
Fibrous Connective TissueDense Regular
Connective Tissue

• Tightly packed collagenous fibers run parallel to
  direction of force
• Tendons and ligaments

http//www.lab.anhb.uwa.edu.au/mb140/CorePages/Con
nective/Images/skm40vg.jpg
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Supportive Connective TissueHyaline Cartilage

• Homogeneous matrix
• Fine collagenous fibers not visible
• Lined by perichondrium
• Costal cartilages, articular surfaces of bones,
  trachea, larynx

http//www.sunyniagara.cc.ny.us/val/hyaline1.html
19
Supportive Connective TissueCompact Bone

• Structure
• Osteocytes confined to lacunae
• Lacunae interconnected by canaliculi
• Central canal contains blood supply
• Lamellae surround central canal

20
Fluid Connective TissueBlood

• Cellular Component
• Formed elements
• Erythrocytes
• Leucocytes
• Thrombocytes
• Matrix
• Liquid plasma

21
Nervous Tissue

• Neuron is the basic structural unit.

22
Muscular Tissue

• Three types
• Smooth
• Cardiac
• Skeletal

23
Laboratory ObservationsConnective Tissues

• Connective Tissue
• Loose (areolar)
• Dense Regular (white fibrous)
• Adipose tissue
• Hyaline cartilage
• Identify lacuna, chondocyte
• Bone
• Identify lamella, central canal, lacuna,
  osteocyte

• The histology of blood, muscular tissue, and
  nervous tissue will be studied when those systems
  are studied in later chapters.

24
Glands

• Exocrine
• Maintain contact with a body surface by way of a
  duct.
• Release a secretion to a body surface.
• Sweat glands, mammary glands, pancreatic acini.
• Endocrine
• Lost contact with a body surfaceno ducts.
• Release secretion to blood.
• Thyroid gland, islet cells of pancreas.

25
Serous vs. Mucous Exocrine Secretions

• Serous glands
• Thin, watery secretions
• Sweat glands
• Pancreatic acini

• Mucous glands
• Thick, viscous secretions
• Tongue
• Roof of mouth
• Respiratory passages

26
Membranes

• Cutaneous
• The skin
• Mucous membrane (mucosa)
• Lines passageways that open to the exterior
• Digestive tract and respiratory passageways
• Goblet cells secrete mucus that traps foreign
  particles, and protects from chemical and
  physical abrasion.
• Serous membrane
• Lines body cavities and outer surfaces of some
  organs (e.g., stomach)
• Secretes watery (serous) fluid derived from blood.

Mucous membrane
27
Histology Review

• A group of cells with similar origin and function
  is called a(n) ____________.
• _________ is a tissue that lines kidney tubules.
  Its cells are in a single layer and they are
  about as tall as wide as deep.
• In _____________ all cells reach the basement
  membrane but the nuclei are at different levels.
  The tissue appears stratified but it is not.
  Many cilia line the outer surface of these cells.
  This tissue is found in the ____________.
• __________ is a form of fibrous connective tissue
  modified for fat storage.
• Lacunae and chondrocytes are a feature of this
  tissue __________.
• A connective tissue surrounding the outside of a
  bone is ____________.
• _____________ is an example of a mucous membrane.
  The cells that secrete mucus are called
  ______________.
• Identify the tissues in the following slides

28
Tissue Identification
a.
b.
http//upper.usm.k12.wi.us/academics/faculty/rheun
http//upper.usm.k12.wi.us/academics/faculty/rheun
c.
d.
http//kentsimmons.uwinnipeg.ca/cm1504/15lab42006/
http//virtual.yosemite.cc.ca.us/randerson/Lynn's
20Bioslides/117.jpg
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Answers

• Tissue
• Simple cuboidal epithelium
• Pseudstratified columnar epithelium/ trachea
• Adipose tissue
• Cartilage
• Periosteum
• Digestive tract (etc.)/ goblet cells.

• Slides
• Simple columnar epithelium
• Pseudostratified columnar epithelium
• Dense regular connective tissue
• Hyaline cartilage