Anatomy & PhysiologyChapter 3 – Part 3

Tissues

Body Tissues

• Tissues– Groups of cells with similar structure and

function– 4 primary types:

• Epithelium• Connective• Nervous• Muscle

Epithelial Tissues

• Found in different areas:– Body Coverings– Body Linings– Glandular Tissue

• Functions:– Protection– Absorption– Filtration– Secretion

Epithelial Tissues

• Epithelium Characteristics:– Cells fit closely together– Have no blood supply of their own

Classification of Epithelium

• Number of Cell Layers:– Simple = one layer– Stratified = more than

one layer

• Shape of Cells:– Squamous = flattened– Cuboidal = cube

shaped– Columnar = column

like

Classification of Epithelium

Connective Tissue

• Includes the most abundant tissues

• Functions:– Binds body tissues together– Supports the body– Provides protection

Connective Tissue

• Extracellular Matrix:– Non-living material that surrounds living cells– Two main elements:

• Ground substance = mostly water along with proteins and polysaccharides

• Fibers

Muscle Tissue

• Function is to produce movement

• Three types:– Skeletal Muscle– Cardiac Muscle– Smooth Muscle

Nervous Tissue

• Comprised of neurons and nerve support cells

• Function is to send impulses to other areas of the body

Tissue Repair

• Regeneration– Replacement of destroyed tissue by the same

kind of cells

• Fibrosis– Repair by dense fibrous connective tissue

(scar tissue)

Events in Tissue Repair

• Capillaries become very permeable

• Regeneration of surface epithelium

Regeneration of Tissues

• Tissues that regenerate easily:– Epithelial– Fibrous Connective– Bone

• Tissues that regenerate poorly:– Skeletal Muscle

• Tissues that are replace largely with scar tissue:– Cardiac Muscle– Nervous tissue within the brain and spinal cord

Developmental Aspects of Tissues

• With old age there is a decrease in mass and viability in most tissues.

Developmental Aspects of Tissues

• Some cells lose their ability to divide when they are fully mature.– This is called AMITOTIC– For example: heart muscle and nervous tissue– However, if these tissues are injured, the lost cells

cannot be replaced by the same type of cells but by scar tissue.

• If a cell multiplies wildly, the abnormal cell mass is known as NEOPLASM.– May be benign or malignant (cancerous)

Simple Epithelium

• Simple Squamous– GD: Single layer of flat

cells– Location: Lines body

cavities– Location: Lines lungs

and capillaries

Simple Epithelium

• Simple Cuboidal– GD: Single layer of

cube-like cells– Location: Covers the

ovaries

Simple Epithelium

• Simple Columnar– GD: Single layer of tall

cells– GD: Includes GOBLET

CELLS – produce mucus for secretion

– Location: Lines the digestive tract

Simple Epithelium

• Pseudostratified– GD: Single layer, but

some cells are shorter than others

– Location: Found in the respiratory tract – has cilia

Stratified Epithelium

• Stratified Squamous– GD: Several layers of

flat cells– Location:

• Skin• Mouth• Esophagus

Stratified Epithelium

• Transitional Epithelium– GD: Shape of cells

depends upon the amount of stretching

– Location: Lines organs of the urinary system to help stretch the bladder

Glandular Epithelium

• Gland = one or more cells that secretes a particular product

• Two major gland types:– Endocrine Glands

• Ductless• Secretions hormones directly into the blood

– Exocrine Glands• Have ducts• Include sweat and oil glands

Connective Tissue Types

• Dense Connective– Made up of collagen

fibers– Examples: tendons

and ligaments

Connective Tissue Types

• Adipose– Made of areolar tissue

with fat globules– Functions:

• Insulates the body• Protects organs• Serves as a site of fuel

storage

Connective Tissue Types

• Areolar– Most widely distributed

connective tissue– Soft tissue– Contains all fiber types

Connective Tissue Types

• Hyaline Cartilage– Most common

cartilage– Entire fetal skeleton is

hyaline cartilage

Connective Tissue Types

• Elastic Cartilage– Made of elastic fibers– Provides elasticity– Example: supports the external ear

Connective Tissue Types

• Fibrocartilage– Highly compressible– Example: forms

cushion-like discs between vertebrae

Connective Tissue Types

• Bone– Composed of a hard

matrix of calcium salts– Used to protect and

support the body

Connective Tissue Types

• Blood– Blood cells are

surrounded by fluid matrix

– Functions as the transport vehicle for materials

Connective Tissue Types

• Reticular– Delicate network of

interwoven fibers– Forms internal support

for the lymph nodes, spleen, and bone marrow

Muscle Tissue Types

• Skeletal Muscle– GD: Can be controlled

voluntarily– GD: Cells are striated– GD: Cells have more

than one nucleus– Location: Attached to

the bones– Function: Movement

Muscle Tissue Types

• Smooth Muscle– GD: Involuntary– GD: No visible

striations– GD: One nucleus per

cell– Location: Surrounds

hollow organs– Function: movement

Muscle Tissue Types

Cardiac Muscle– GD: Cells are striated– GD: One nucleus per

cell– GD: Involuntary– Location: ONLY in the

HEART– Function: pump blood