Tissues
Chapter 3
Types of tissues
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Tissues – group of cells that have specialized
structural and functional roles
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All tissues in the same type will have similar
functions
4 Types of tissue
Epithelial, Connective, Muscle, Nervous
Epithelial tissues
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They are the exposed tissues in the body
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Always have one surface open
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They are found throughout the body
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covering organs, inner lining of body cavities, and lines
hollow organs
Examples of where it would be?
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These are very tightly packed cells, so there is
little material in between them
Epithelial tissues
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Epithelial tissues lack blood vessels
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Nutrients are able to diffuse from the underlying
connective tissues
Epithelial cells divide the fastest of any tissue
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How do they get nutrients?
Why would that be?
Functions of epithelial tissues:
Main: be a protective barrier
 Secondary: secretion, absorption, and sensory
reception
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Epithelial tissues
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When studying the types of epithelial tissues, remember:
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Simple Squamous Epithelium
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Simple = Single layer, stratified = multiple layers
Squamous = flattened, cuboidal = cube, columnar = column
Single layer, flattened cells
Fit tightly together (ex. Floor tiles)
Easily damaged
Very effective at sites of diffusion
Where would we find these?
Lines air sacs in lungs, lines inside of blood vessels
Pictures
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Simple squamous
Epithelial tissues
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Simple Cuboidal Epithelium
Small cube shaped, single layer
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Covers some glands (function = secretion)
Simple Columnar Epithelium
Column shape, single layer
Create a very thick layer
 function = protection
 Usually secretes mucus
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Pictures
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Simple cuboidal
simple columnar
Epithelial tissues
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Pseudostratified Columnar Epithelium
Single layer but looks like multiple
Have cilia
 Line respiratory system – Why?
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Stratified Squamous Epithelium
Many layers, flattened cells, cells underneath
replicate quickly
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Forms outer layer of skin
Pictures
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Pseudostratified
Stratified squamous
Epithelial tissues
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Stratified Cuboidal Epithelium
Two or three layers, cube shape
Also covers some glands
 Provide more protection than single layer
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Stratified Columnar Epithelium
Several layers, column shaped
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Found in reproductive tract
There are other types but we won’t cover those
Pictures
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Stratified cubiodal
stratified columnar
Epithelial Tissues
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Review:
Pages 86-90
Pictures of each type on pages 88 – 89
When studying the types of epithelial tissues,
remember:
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Simple = Single layer, stratified = multiple layers
Squamous = flattened, cuboidal = cube, columnar = column
There are 7 types that we talked about
Assignment
1.
2.
3.
4.
How are Simple Squamous Epithelium like
floor tiles?
Why would Simple Columnar Epithelium
secrete mucus?
How does Pseudostratified Columnar
Epithelium having cilia help its function?
Rename the following types of epithelium:
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Single layer cube cells
Multilayered flat cells
Multilayered cells that are taller than they are wide
Connective Tissues
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What is connective tissue?
The most general type of tissues
 This is a group of tissues that is very diverse
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They also serve several functions:
Provide support, provide protection, serve as a
framework, fill spaces, store fat, produce blood
cells, protect against infections, and help repair
tissue damage
Connective Tissues
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In general connective tissues:
Have a rich blood supply, this gives them plenty
of nutrients
Are farther apart than epithelial cells
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Why would this be?
Not as necessary for protection
Can divide – but not all of them are able to.
Contain three different types of fibers
Have six different types of tissues
Connective Tissues
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The three types of connective tissue fibers are:
1. Collagenous Fibers – thick threads of the
protein collagen
Flexible but not elastic
Have great tensile strength – useful in areas that
hold structures together
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where would this be?
Ligaments and tendons
Connective Tissue Fibers
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2. Elastic Fibers – Thin branching fibers of
the protein elastin
Not as strong as collagen but able to stretch.
Common in body parts that need the ability to
quickly stretch frequently (ex: vocal cords)
***The under layers of skin contain both of the
above types***
3. Reticular Fibers – thin, branching
collagenous fibers
Connective Tissue Types
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1. Loose Connective Tissue
Forms delicate, thin membranes throughout the
body.
The cells of this tissue are a good distance apart
The area between cells contains many
collagenous and elastic fibers
Where would this be found?
It lies underneath most layers of epithelium and
attaches the skin to underline tissue
Connective Tissue Types
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2. Adipose Tissue
Another name for this is … fat tissue
Found in many areas around the body including:
Under the skin, around the kidneys, around
heart, behind eyeballs, in abdominal region
What would this be used for?
Used to cushion some joints and organs, as well
as insulate the body, and store excess fat
Connective Tissue Types
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3. Dense connective tissue
Consists of many tightly packed collagenous
fibers, and a few elastic fibers
Would this tissue be strong or weak?
Strong
Used to connect structures together
Where would this be found?
Ligaments and tendons are the most common
areas
Connective Tissue Types
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4. Cartilage
Rigid connective tissue, used mainly for support
Found all over the body (joints, ears, nose, etc.)
Does not have a direct blood supply
How does this affect how cartilage is repaired?
3 types of cartilage
Hyaline cartilage – found in nose, trachea, some joints
 Elastic cartilage – framework for external ear, larynx
 Fibrocartilage – toughest, found in spine, and knees
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Connective Tissue
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5. Bone
Most rigid connective tissue
This is due to the mineral deposits between cells
Very well supplied with blood, therefore it heals much
quicker than cartilage
Where is this located?
All throughout the body in bones
What are the functions?
Support, protection, production of blood cells, storage
of minerals
Connective Tissue
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6. Blood
Functions: transports substances, exchange of
gases, help maintain homeostasis
Found all throughout the body within the blood
vessels
Composed of:
Red blood cells
 White blood cells
 Platelets
 Plasma
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Connective Tissue
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Review
Most general category of tissues, many uses
Table 5.4 on page 109
Collagen Fibers – used for?
Elastic Fibers – used for?
Reticular Fibers – used for?
Six types of tissues:
Loose, Adipose, Dense, Cartilage, Bone, Blood
Muscle Tissue
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Not as diverse as a group
Muscle tissues are contractile
What does that mean to you?
The cells are elongated and they can shorten
As each cell shortens, it shortens the tissue, thus
moving the body part
Three types of muscle tissue
Pictures --- Pg. 110 – 111
Table 5.5 on pg. 112
Muscle Tissue
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1. Skeletal Muscle Tissue
This is the kind that most people think of.
Found in muscles that attach to bones
These enable use to talk, throw, walk, etc.
Controlled by conscious effort (voluntary)
Have striations
Striations – alternating light and dark regions
Muscle Tissue
Muscle Tissue
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2. Smooth Muscle Tissue
Lacks striations – therefore it looks smooth
Shorter than skeletal muscle
Found in the walls of hollow organs
Examples: stomach, intestines, bladder, etc.
Cannot be stimulated by conscious effort
(involuntary)
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Example: movement of food through the digestive
system
Muscle Tissue
Muscle Tissue
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3. Cardiac Muscle Tissue
Striated – but differently than skeletal muscle
Found only in the heart (cardiac = heart)
This tissue forms most of the heart
Voluntary or involuntary?
Cells are connected by intercolated disks
This allows for all cells to fire at once
 Why would this be important?
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Muscle Tissue
Nervous Tissue
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Where are they found?
Nerves, brain, spinal cord
Functions:
Transport messages throughout the body, to and
from the brain
Stimulate muscles for movement
Coordinate other bodily functions
Assignment
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Pg 114
RE 2, 14, 16, 20, 22
 CT 4
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