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Histology
The Study of Tissues
Chapter 5
 Cells are arranged in tissues that perform specialized
structural and functional roles
 Four Major Types of Tissue:
 Epithelial
 Connective
 Muscle
 Nervous
 General Characteristics
 Covers free body surfaces
 Major tissue of glands
 Anchored to connective tissue by basement membrane
 Lacks blood vessels
 Contains little intercellular material
 Replaced continuously
 Functions to protect, secrete, absorb and excrete
 Single layer of thin
flattened cells
 Functions in the
exchange of gases in
the lungs and lines
blood vessels and
various membranes
 Single layer of cube-
shaped cells
 Carries on secretion
and absorption in the
kidneys and various
glands
 Composed of elongated
cells whose nuclei are
located near the
basement membranes
 Lines the uterus and
digestive tract
 Often have absorbing
cells that possess
microvilli
 Contains goblet cells
that secrete mucus
 Appears stratified
because nuclei are
located at two or more
levels
 May have cilia that move
mucus or sex cells
 Lines tubes of
respiratory and
reproductive systems
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Composed of many layers
Protects underlying cells
Covers the skin
Lines the mouth, throat, vagina and anal canal
 Lines larger ducts of the mammary glands, sweat
glands, salivary glands and pancreas
 Protects
 Composed of two or three layers of cube-shaped cells
 Top layer of cells in
contains elongated
columns, bottom
layers are cubeshaped
 Found in male urethra
and vas deferens
 Also in parts of the
pharynx
 Tissue protects and
secretes
 Specialized to change under tension
 In the walls of various organs of the urinary system
 Composed of cells specialized to secrete substances
 Glands consist of one or more cells
 Exocrine glands secrete into ducts
 Endocrine glands secrete into tissues fluid or blood
 Exocrine glands classified according to the composition of
their secretions
 Merocrine glands secrete fluid without loss of cytoplasm
 Apocrine glands lose portions of cells during secretion
 Holocrine glands release cells filled with secretory products
 Serous cells secrete watery fluid with high enzyme content;
mucous cells secrete mucus.
 General Characteristics
 Connects, supports, protects, provides framework, fills
spaces, stores fat, produces blood cells, protects against
infection, helps repair damaged tissues.
 Located some distance apart
 Intercellular matrix consists of fibers and ground
substances
 Fibroblast
 Produces collagenous and elastic fibers
 Macrophages:
 Function as phagocytes
 Mast cells can release heparin and histamine located
near blood vessels
 Collagenous fibers
 Composed of collagen and have great tensile strength
 Dense Connective Tissue
 Tissue consisting mainly of collagenous fibers
 Elastic Fibers
 Composed of microfibrils embedded in elastin and are
elastic
 Reticular Fibers
 Very fine collagenous fibers
 Dense Connective
Tissue
 Reticular Fibers
 Forms thin
membranes between
organs
 Found beneath skin
and between muscles
 Specialized form of
loose connective
tissue that stores fat
 Found beneath
skin, certain
abdominal
membranes, around
kidneys, heart, and
joints
 Composed of strong
collagenous fibers
 Found in tendons,
ligaments, white
portions of the eyes
and deep layer of skin
 Provides framework
 Composed of fibers and gel-like ground substance
 Usually enclosed in a perichondrium
 Lacks direct blood supply and is slow to heal
 Major Types
 Hyaline
 Elastic
 fibrocartilage
 Contains mineral salts and
collagen
 Cells usually in concentric
circles around osteonic
canals and are
interconnected by
canaliculi
 Active tissue that heals
rapidly
 Transports substances and
helps maintain a stable
internal environment
 Composed of red cells,
white cells, and platelets
suspended in plasma
 Formed by special tissue
in the hallow parts of
certain bones
 Composed of phagocytic
cells that are widely
distributed throughout
body
 Defends the body against
invasion by
microorganisms
 General Characteristics
 Muscle tissue contract causing tissues around them to
move
 Work in pairs (Extension/Flexion)
 Three Types
 Skeletal
 Smooth
 Cardiac
 Muscles containing this
tissue usually are attached
to bones and controlled
by conscious effort
 Cells, or muscle fibers, are
long and threadlike
 Muscle fibers contract
when stimulated by nerve
action and then relax
immediately.
 In the walls
of hollow
internal
organs
 Usually, it’s
controlled by
involuntary
activity
 Found only in the heart
 Cells are joined by
intercalated disks and
form branched networks.
 Found in the brain, spinal cord, and peripheral nerves
 Neurons (nerve cells)
 Sense changes and respond with nerve impulses to other
neurons or body parts
 Coordinate, regulate, and integrate body activities
 Neuroglial Cells
 Some forms bind and support nervous tissue
 Other carry on phagocytosis
 Still others connect neurons to blood vessels
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Nerve Fiber
Cytoplasm
Nucleus
Neuroglial cell Nuclei
Cell Membrane