Department of Zoology The Open University of Sri Lanka 1

Content  Learning Outcomes  Introduction  Epithelial tissues  Connective tissue  Muscular Tissue  Nervous Tissue  Classification of tissues 2

3 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 muscle tissues in terms of location, structure, and function

 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. 4 Introduction

 There are four types of tissues found in an animal. 1. Epithelial tissue 2. Connective tissue 3. Muscle tissue 4. Nervous tissue 5 Introduction

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. 6

3. Muscle tissue Shortening and lengthening to move other tissues. 4. Nervous tissue Allowing rapid flow of ions in and out to conduct signals Nucleus of schwann cell Layer of myelin Axon Node of ranvier Terminal knob Myelin sheath Axon Cell body Nucleus Dendrites 7

 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) 8

 There are three types of cells in epithelial tissues 1.Squamous – thin flat cells 2.Cuboidal – cells are roughly square 3.Columnar - elongated cells. 9

 Three types of cell layers exist in epithelium tissues Epithelium tissue Simple epithelium Stratified epithelium Pseudo epithelium 10

 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 11 Glandular epithelium

Exocrine glands Endocrine glands 12 Glandular epithelium

Functions of epithelial tissues 1.Provides physical protection 2.Controls permeability 3.Detects sensations (sight, smell, taste, equilibrium) 13

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. 14

 Connective tissue is made up of cells, ground substances and fibers. Ground substances together with fibers make matrix. 15 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) 16 Connective tissue

Blood tissue - (composed of blood cells, cell fragments and blood plasma) 17 Connective tissue

D. Bone tissue (two types; compact and spongy) compact – with osteons spongy - no osteons 18 Connective tissue

3.Muscular Tissue  Muscle cells are elongated and are called as muscle fibers  These cells have main properties  Excitability ( ability to respond to stimuli) 19

 Contractibility (ability to contract)  Extensibility (ability to be stretched without tearing)  Elasticity (ability to return to its normal shape) 20 Muscular Tissue

 Muscle tissue is classified into three types (Cardiac, Skeletal and Smooth) 21 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. Bone Tendon Blood vessel Muscle fiber Fascicle Perimysium Epimysium Endomysium 22 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 23 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 24 Muscular Tissue

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. 25

 Cells of nervous tissue have three principal parts 1.Dendrites 2.Cell body 3.Axon Nucleus of schwann cell Layer of myelin Axon Node of ranvier Terminal knob Myelin sheath Axon Cell body Nucleus Dendrites 26 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. 27 Nervous Tissue

Squamous Cuboidal Columnar Cilliated Glandular Areolar Adipose Skeletal Fluid Striated Smooth Cardiac Tendon Ligament Bone Cartilage Blood Lymph 28

29 Author- Mrs. W.A.Y. Chandrani Web Content Developer – Chameera Kendaragama Produced by The Open University of Sri Lanka 2014