Chapter 5
Tissues
Intercellular Connections
• Individual cells connect to form tissues 3
ways:
– Tight junctions– Desmosome- adhesion between cells in
spots. Allows from some permeability.
– Gap junctions- cytoplasms of adjacent cells
are connected through transport proteins.
• Ions can pass freely through cells.
Intercellular Connections
Tissue Types
A tissue is a group of cells with a common
structure & function
The human body is composed of four main
tissue types:




1.
2. Connective
3.
4. Nerve
Epithelial Tissue
Epithelial Tissue
Characteristics

Always has a free (apical) surface
exposed to outside or open space.



Has a basement membrane to anchor
underlying tissue
Functions

Covers body surfaces



Protects
Absorbs


Excretes
Classified by Shape


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Squamous –
Cuboidal –
Columnar –
Classified by Shape
May occur in layers:
 Simple –
 Stratified – 2 or more layers
 Pseudostratified –


Example – simple cuboidal
Example – stratified columnar
Examples of Epithelial
Tissue
s
Simple Squamous- Thin, flattened cells.
Allow for diffusion and filtration. Line air sacs of
lungs and walls of capillaries.
Simple cuboidal-single layer of cube
shaped cells. Lines follicles of thyroid gland,
kidneys and ducts of certain glands.
Simple columnar- single layer of
elongated cells. Can contain cilia, used for protection
and absorption in digestive tract.
Stratified squamous- Layers of
squamous cells. Make up epidermis and line cavities
exposed to external environment.
Stratified columnar- Several layers of
columnar cells overlying cuboidal cells near the
basement membrane.
Pseudostratified ciliated
columnar- Appear stratified but are not. Often
contain cilia and goblet cells which secrete mucus.
Pseudostratified ciliated columnar
w/goblet cells- Line Respiratory passages to trap
unwanted particles
Transitional tissue- Changes in
response to change in tension. Line urinary bladder
and urethra.
Glandular Epithelium
• Specialized to secrete substances
•
• Those that secrete substances into ducts
that open onto a surface are
• Those that secrete into tissues or blood
are
Classifying Glands by Structure
• Simple• Compound- duct that does branch before
secretory portion.
Classifying Glands by Type of
Secretions
3 types:
•
•
•
•
• No loss of cytoplasm
in secretions
• Ex. – pancreas
Small portions of cells
in secretions
Ex. – mammary glands
Classifying by Secretions
• Secretions w/entire cells filled w/secretory
products; ex. – sebaceous (oil) glands
Connective Tissue
Functions





1. connects
2.
3. protects
4.
5. fills spaces
Functions





6. stores fat
7.
8. protects against infection
9.
10.helps repair damaged tissue
Characteristics



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1. Consists of cells in a matrix
(intercellular material)
2. Cells some distance apart
3.
4.
Types of Fibers:
1.
collagenous – composed of collagen
(protein); have great tensile strength;
slightly
elastic;
compose
bones,
tendons &
ligaments
Types of Fibers - continued

elastic – composed of elastin (protein);
very elastic but weaker; compose vocal
cords & air passages of lungs
Types of Fibers - continued


Reticular – composed of very fine
collagenous
fibers.
Types of Cells
1. Fixed cells – stay in one place &
have stable numbers; 2 types:

fibroblasts – large & star-shaped;
most prevalent
Types of Cells - continued

mast cells – may release heparin (for
blood clotting) &
histamines (promotes
allergic reactions &
inflammation);
usually located near
blood vessel walls
Types of Cells - continued
2. Wandering cells –

macrophages –
(Purple cells – macrophages,
Green cells – T-lymphocytes)
Examples of Connective
Tissue
Areolar tissue- binds the skin to
underlying organs and under epithelium to provide
bloodflow.
Adipose tissue- connective tissue
composed of fats, cushion joints and provide
insulation
Regular dense connectivestrong fibers bind body parts together. Found in
ligaments and tendons.
Irregular dense connectivedisorganized and strong. Found in the dermis
Hyaline cartilage- Most common, found
on ends of bones, nose cavity and supporting rings of
resp. system.
Fibrocartilage- tough tissue containing
collagenous fibers. Shock absorbers between
vertebrae.
Elastic cartilage- flexible cartilage make
up ears and larynx
Blood - platelets
Blood – red cells & white cell
Elastic connective
Reticular connective
Bone- A- central canal (contains blood vessels)
B- Canaliculi- minute tubes allow for movement
between cells.
Bone- D- Lamellae (layers of osetocytes), Costeocytes
Muscle & Nerve Tissue
Muscle Tissue
3 types:
 Skeletal

Smooth- lacks striations found in skeletal,
used for involuntary movements


Used for movement
Ex- move food through digestive tract
Cardiac-
3 Types of Muscle Tissue
Smooth muscle- B- nucleus
Skeletal muscle- A- striations, B- nucleus
Cardiac muscle
Nervous Tissue
• Found in the brain, spinal cord and
peripheral nerves.
• Cells called neurons
–
• Also include neuroglia cells (support cells)
– Support the function of the neurons
Nerve tissue – A- neuron, B- Axon, Cneuroglia