Chapter Four:
Tissue: The Living Fabric
M.C. Shamier, MD
Shenzhou University
Histology
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Greek: ἱστός “tissue” and –λογία “the study of”.
The study of tissue or microscopic anatomy
Types of Tissue
Epithelial Tissue
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Epithelium is a sheet of cells covering a body surface or
lining a cavity
Different functions: protection, absorption, filtration,
excretion, secretion and sensory reception.
Name of epithelium:
-number of layers
-cell type
Epithelium Characteristics
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Closely packed cells
Polarity: apical surface and (attached) basal surface
Supported by underlying connective tissue
Innervated but avascular (nerves but no blood vessels)
High regenerative capacity
Simple vs Stratified
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Simple epithelia are mostly concerned with absorption,
secretion and filtration.
Stratified epithelia’s main function is protection
Cell Shape
Study!
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Description
Function
Location
For each of the types of epithelia, see table in book
Glandular epithelia
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Gland: one or more cells producing and secreting a
particular product (secretion) such as hormones or
digestive enzymes.
There are unicellular and multicellular glands
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Endocrine glands: for ‘le milieu intérieur’
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Thyroid gland, pituitary, testis and ovary
Exocrine glands: for ‘le milieu extérieur’
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Pancreas, salivary glands, liver, sweat glands
The goblet cell: unicellular exocrine gland
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Intestinal and respiratory tracts
Multicellular exocrine glands
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Composed of:
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a secretory unit
a duct
Connective Tissue
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Functions
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binding and support, protection, insulation, and transportation.
Ranges from avascular to highly vasculized
Composed mainly of ECM (extracellular matrix)
Four Types of Connective Tissue
Connective tissue proper
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Loose
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Adipose
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Reticular
Areolar
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fat: nutrient storage, protection,
insulation
lymph nodes, spleen, bone marrow
binds body parts together
Dense
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Regular
closely packed collagen, tendons and
ligaments
Irregular
thick irregularly arranged collagen,
dermis
Cartilage
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Hyaline cartilage: firm support, most abundant
Elastic cartilage: strength and exceptional stretchability
(ear)
Fibrocartilage: strong support, heavy pressure
(intervertebral discs)
Bone: description and functions
Blood: decription and functions
Study!
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Description
Function
Location
For each of the types of connective tissue, see table in
book
Nervous tissue
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The main component of the nervous system
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Central nervous system (Brain and spinal cord)
Peripheral nervous system
Two cell types
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Neurons: generate and conduct impulses
Supporting cells: not conductive
Nervous tissue: neurons (cellbody,
axon, dendrites)
Muscle tissue
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Skeletal muscle
Cardiac muscle
Smooth muscle
voluntary
heart walls
hollow organs
More arrangement in
muscle fibers
Epithelial membranes
a)
b)
c)
Cutaneous
Mucous
Serous
Tissue Damage
Pressure sores (decubitus)
Step 1: Inflammation
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5 components
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Dolor
Rubor
Calor
Tumor
Functio laesa
Pain
Redness
Heat
Swelling
Loss of function
Step 2: Organization
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Organization and restored blood supply
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The blood clot is replaced with granulation tissue
Epithelium begins to regenerate
Fibroblasts produce collagen fibers to bridge the gap
Debris is phagocytized (eaten by white blood cells)
Step 3: Regeneration and Fibrosis
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Regeneration and fibrosis
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The scab detaches
Fibrous tissue matures; epithelium thickens and begins to
resemble adjacent tissue
Results in a fully regenerated epithelium with underlying scar
tissue
End of Chapter Four