CHAPTER 5

Body Tissues and Membranes

What are tissues?

Cells are organized into groups and layers called TISSUES

Each tissue is composed of similar cells that are specialized to carry on a particular function◦Secretion◦Absorption◦Support

Tissue Types

Epithelial

Connective

Muscle

Nervous

Epithelial Tissue

Covering of all major body surfaces

Makes up glands

Always has one free surface and one that’s attached to connective tissue◦ Basement

Membrane

Free Surface

Basement Membrane

Connective Tissue

Epithelial Tissue

Lacks blood vessels◦ Nutrients diffuse

from capillaries of underlying tissue

Rapid rate of reproduction◦ Constantly

sloughed off

Tightly packed◦ Create good

barriers

Epithelial Terms

Shape◦Squamous-flat, thin cells◦Cuboidal-cube shaped cells◦Columnar-tall, elongated cells

Layers◦Simple-single layer◦Stratified-two/more layers

Types of Epithelial Tissue

Simple Squamous Epithelium◦ Single layer of “pancake” cells◦ Easy diffusion◦ Lung alveoli (air sacs), capillaries

Nucleus

Simple Cuboidal◦ Single layer of cube-shaped cells

Primarily secretory cells Ovaries, kidneys, salivary glands

Types of Epithelial Tissues

Centrallylocated nucleus

Types of Epithelial Tissue Simple Columnar

◦ Protection / Absorption◦ Microvilli

Increase surface area

◦ Digestive tract

Nuclei located on same level

Types of Epithelial TissuePseudostratified Columnar

◦Similar to S.C.◦Have cilia along edge

Line respiratory system

Note: hownuclei are attwo or more layers

Goblet cell:secretes mucus

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Types of Epithelial Tissue

Stratified Squamous◦ Many layers thick◦ New ones push old ones

up Epidermis

Stratified Cuboidal◦ 2 or 3 layers of

cuboidal cells

Stratified Columnar◦ 2 or 3 layers of columnar

cells

Types of Epithelial Tissue

Transitional Epithelium◦Responds to tension - stretches out◦Creates protective barriers◦Lining of bladder & ureters

Glandular Epithelium

Specialized to produce and secrete substances

Make up glands◦ Exocrine glands -

dump secretions into ducts

◦ Endocrine glands - dump secretions into bloodstream

Epithelial Tissue

-Cells readily divide

-Cells are continually replaced

-Cells are tightly packed -Classified by shape and number of layers

Connective Tissue

Most abundant type of tissue by weight

Functions:◦ Support◦ Stores fat◦ Produces blood

cells◦ Protection from

infection

Connective TissueCells spaced further apart than epithelia

Types of Fibers

Collagenous fibers - thick, made of collagen◦ Strong, slightly elastic,

flexible◦ Ligaments, tendons

Elastic fibers- made of elastin◦Branched, stretch easily

◦Vocal cords

Loose Connective Tissue

◦ Binds skin to underlying tissue

◦ Lies beneath most epithelial tissue

Adipose Tissue (FAT)

Form of loose connective tissue

◦ Protective cushion◦ Stores energy

Dense Connective Tissue

◦ Binds body parts together

◦ Make up tendons, ligaments

CartilageRigid

Protection, support

Ends of bones, nose, external ears, larynx, between vertebrae

BoneMost rigid

Functions:◦ Internal structure◦ Attachment for

muscles◦ Blood formation◦ Inorganic mineral

storage

Other Connective Tissues

Blood ◦ Transports

substances between cells and external environment

Muscle TissueContractile - tissue

can contract, becoming shorter and longer

◦ Causes body parts to move

3 types:◦ Skeletal muscle-

bones◦ Smooth muscle-

organs◦ Cardiac muscle-heart

only

Nervous Tissue

Found in brain, spinal cord, nerves

Neurons - basic nerve cells

Respond to changes in environment and send messages

Epithelial tissue

Smooth muscle