Department of Zoology
The Open University of Sri Lanka1
Content
 Learning Outcomes
 Introduction
 Epithelial tissues
 Connective tissue
 Muscular Tissue
 Nervous Tissue
 Classification of tissues
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Learning Outcomes
By the end of this session you should be able to:
 list the major functions of each of the four major animal
tissue types
 give the functions carried out by epithelial tissue types
and state their general location/s
 describe the basic features of connective tissue, and
explain how the cells of this tissue type enable
connective tissue to carry out its various tasks.
 distinguish among skeletal, cardiac, and smooth
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muscle tissues in terms of location, structure, and function
Introduction
 Multicellular (large) organisms function more
efficiently if cells become specialized for specific
functions.
 A tissue is composed of cells that function together in a
specialized activity.
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Introduction
 There are four types of tissues found in
an animal.
1. Epithelial tissue
2. Connective tissue
3. Muscle tissue
4. Nervous tissue
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1. Epithelial tissue
Forming tight covering and
protecting layers below
2. Connective tissue
Holding other tissues
together and are surrounded by
lots of nonliving material.
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3. Muscle tissue
Shortening and lengthening to
move other tissues.
4. Nervous tissue
Nucleus of
schwann cell
Dendrites
Layer of myelin
Allowing rapid flow of ions
in and out to conduct
signals
Nucleus
Axon
Cell body
Axon
Myelin sheath
Node of ranvier
Terminal knob
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1.Epithelial tissues
 Two types of epithelial tissues
1. Covering and lining epithelium ( outer layer of the
skin and some organs)
2. Glandular epithelium
( constitute the secreting portion of glands)
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Epithelial tissues
 There are three types of cells in epithelial tissues
1. Squamous – thin flat cells
2. Cuboidal – cells are roughly square
3.Columnar - elongated cells.
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Epithelial tissues
 Three types of cell layers exist in epithelium tissues
Epithelium
tissue
Simple
epithelium
Stratified
epithelium
Pseudo
epithelium
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Glandular epithelium
 Glands are made up of single or a mass of epithelial
cells.
 Two types of glands
1. Exocrine - Secrete their products in to ducts
Eg . Salivary glands and mammary glands
2. Endocrine - Secrete their products into blood
stream
Eg. Pancreas
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Glandular epithelium
Exocrine glands
Endocrine glands
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Functions of epithelial tissues
1. Provides physical protection
2. Controls permeability
3. Detects sensations (sight, smell , taste,
equilibrium)
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2. Connective tissue
 Most abundant and most widely distributed
tissue in the body.
 These tissues provide support for organs and the
body as a whole, protect and insulate internal
organs and compartmentalize structures such as
skeletal muscles, nerves.
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Connective tissue
 Connective tissue is made up of cells, ground
substances and fibers. Ground substances together
with fibers make matrix.
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Connective tissue
Connective tissues can be classified as;
A. Loose connective tissue (fibers are loosely woven)
B. Dense connective tissue
(few cells among a dense network of fibers with
little ground substances)
C. Cartilage (tough but flexible)
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Connective tissue
Blood tissue - (composed of blood cells, cell fragments
and blood plasma)
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Connective tissue
D. Bone tissue
(two types; compact and spongy)
compact – with osteons
spongy - no osteons
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3.Muscular Tissue
 Muscle cells are elongated and are called as
muscle fibers
 These cells have main properties
 Excitability ( ability to respond to stimuli)
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Muscular Tissue
 Contractibility (ability to contract)
 Extensibility (ability to be stretched without tearing)
 Elasticity (ability to return to its normal shape)
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Muscular Tissue
 Muscle tissue is classified into three types
(Cardiac, Skeletal and Smooth)
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Muscular Tissue
Skeletal muscles are known as striated muscles or
voluntary muscles.
These muscles are attached to bones by tendons and are
responsible for skeletal movements. Basic unit of a
skeletal muscle is a muscle fiber.
Blood vessel
Bone
Perimysium
Muscle fiber
Fascicle
Endomysium
Epimysium
Tendon
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Muscular Tissue
 Cardiac muscle is unique and found only in
the wall of the heart.
 Its fibers have cross striations .
 This muscle is involuntary.
Cardiac muscle
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Muscular Tissue
 Smooth muscle tissue is made up of thin elongated
muscle cells called smooth muscle fibers.
 These fibers are pointed at their ends and each has a
single , large oval nucleus.
 Each cell has many myofibrils which lie parallel to
one another in striated pattern , as in skeletal muscles.
Autonomic neurons
Nucleus
Muscle fibers
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Nervous Tissue
 Nervous tissue is found in the brain , spinal cord and
nerves and consists of only two principal kinds of cells ,
neurons and neuroglia.
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Nervous Tissue
 Cells of nervous tissue have three principal parts
1. Dendrites
2. Cell body
Dendrites
3. Axon
Nucleus
Nucleus of
schwann cell
Layer of myelin
Axon
Cell body
Axon
Myelin sheath
Node of ranvier
Terminal knob
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Nervous Tissue
 Neuroglial cells that do not transmit impulses but
instead support the activities of the neurons .
 Schwann cells, a type in the peripheral nervous
system only in mammals.
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Tendon
Squamous
Striated
Areolar
Ligament
Cuboidal
Smooth
Adipose
Columnar
Cardiac
Bone
Cilliated
Skeletal
Cartilage
Glandular
Fluid
Blood
Lymph
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Author- Mrs. W.A.Y. Chandrani
Web Content Developer – Chameera Kendaragama
Produced by The Open University of Sri Lanka
2014
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