Connective Tissue
Connective Tissue
 Support and attachment for various organs,
fills body spaces giving body form and
maintenance
 Composed of 3 main elements – cells, fibers
and ground substance (fiber and ground
substance = extracellular matrix or ECM)
 Derived from the embryonic tissue,
mesenchyme
Classification
 Classified based on the nature of the matrix
 Ground substance – amorphous (unstructured)
material that fills the space between cells
 Fibers – 3 types
 Cells – 2 types
3 Types of Fibers
 Collagen fibers (white fivers in fresh tissue, pink on
slide) – strong, non-elastic with great tensile
strength and flexibility
 Elastic fibers (yellow fibers, dark purple on slide) –
thinner, not as strong as collagen fibers, randomly
coiled, wavy look
 Reticular fibers (dark purple on slide) – very thin,
fine fibers that branch extensively and form a
network
Reticular
Collagen
Fibroblasts
Elastic
Cell Types

Cells – 2 types

–blast cells – immature, actively mitotic cells, used to
build matrix

–cyte cells – mature, non-mitotic cells, maintain matrix
CT-Proper
Fibroblast
Fibrocyte
Cartilage
Chondroblast
Chondrocyte
Bone
Osteoblast
Osteocyte
Blood
Hemocytoblast
Various types
(erythrocyte, thrombocyte,
leukocyte)
Classification of Connective Tissue Subtypes
 Mesenchyme (Common embryonic tissue)
 Connective tissue Proper Loose –
 3 specific types: Areolar, Adipose, Reticular
 Connective tissue Proper Dense –
 3 specific types: Regular Dense, Irregular Dense, Elastic
 Cartilage –
 3 specific types: Hyaline Cartilage, Fibrocartilage, Elastic Cartilage
 Osseous (Bone) –
 2 specific types: Compact Bone, Spongy (cancellous) Bone
 Blood –
 Cell types: Erythrocytes (red blood cells), Leukocytes (white blood cells),
Thrombocytes (platelets)
Subtype: Mesenchyme
 Forms the undifferentiated “filling” of the early
embryo
 Forms CT between and within developing tissues
and organs
 In adults, only found in dental pulp
 Consists of mesenchymal cells with stem cell
properties (able to give rise to other cells)
Subtype: Loose CT Proper, Specific Type: Areolar

Loosely organized matrix with all 3 fiber types

Fibrocytes most common cells (flat or spindle shaped),
although mast cells and macrophages (immune cells)
present

Ground substance – semifluid

Functions: widespread flexible framework within and
between organs. Contain blood vessels that nourish
surrounding tissue and is site of immune reactions

Location: beneath epithelial tissues, around and within
muscles and nerves and in come serous membranes,
composes superficial fascia
Subtype: Loose CT Proper, Specific Type: Adipose

Cytoplasm and nucleus compressed to edge of cell
by large lipid droplet

Adipocytes (“signet cells”) filled with fat

Ground substance - very little

Fibers – none

Function: protective cushion and insulation
throughout body

Location: buttocks, breasts, surrounding kidneys,
eye sockets
Subtype: Loose CT Proper, Specific Type: Reticular
 Network of fine (reticular) fibers
 Ground substance – semifluid
 Cells - reticular cell (type of fibroblast that
produces reticular fibers)
 Function: provides supporting framework for
many vascular organs, hematopoietic tissue
and lymph nodes
 Location: spleen, bone marrow, lymph nodes
Subtype: Dense CT Proper, Specific Type: Regular

Closely packed collagen fiber bundles in parallel
arrangement

Ground substance - very little

Fibers - mostly parallel collagen fibers

Cells – Fibrocyte

Function: tensile strength

Location: Tendons, aponeurosis, ligaments. Forms
the deep fascia
Subtype: Dense CT Proper, Specific Type: Irregular

Bundles of collagen fibers (and a few elastic
fibers) randomly interwoven

Ground substance - very little

Cells – fibrocyte

Function – strength from many directions

Locations: most of skin dermis, sheaths around
nerves and tendons
Subtype: Dense CT Proper, Specific Type: Elastic

Bundles of parallel elastic fibers that branch and
unite with one another

Ground substance - very little

Fibers – elastic

Cells – fibrocyte

Function – great elasticity (flexibility)

Location: ligaments of vertebral column and walls
of large arteries
Subtype: Cartilage

Surrounded by a fibrous
membrane called the
perichondrium

Mature cells, called
chondrocytes, lie in
lacunae

Lack blood vessels

Cells derive nourishment
by diffusion from
capillaries in the
perichondrium
Subtype: Cartilage, Specific Type: Hyaline

Matrix - firm with an imperceptible fibers
(collagen) (i.e. fibers not routinely visible)

Most common type of cartilage

Cells - chondrocyte in lacunae (mature)

Function: provides smooth surface so tissues may
move easily over one another. Also provides
flexibility and support

Location: composes much of fetal skeleton prior
to ossification, covers ends of long bones in
adults, cartilaginous part of nasal septum, trachea
and costal cartilage
Subtype: Cartilage, Specific Type: Fibrocartilage

Alternating bundles of collagen fibers and rows of
chondrocytes, lack perichondrium

Matrix - semi-firm thick collagen fibers

Cells - chondrocyte in lacunae

Function: provide support and rigidity to
surrounding structures, strongest of the 3 types of
cartilage

Location: intervertebral discs, pubic symphysis,
meniscus of knee joint
Subtype: Cartilage, Specific Type: Elastic

More flexible and elastic than hyaline cartilage

Matrix - firm with obvious elastic fibers

Cells - chondrocyte in lacunae

Function: provide support to surrounding
structures and to define and shape area in which it
is present

Location: external ear (auricle), auditory tubes,
epiglottis
Subtype: Osseous (Bone)
 Hard, strong and lightweight
 Bone is continually modified and reconstructed
(remodeling)
Subtype: Osseous (Bone), Specific Type: Compact

Compact bone (Ground Bone and decalcified
bone slides)

Composed of functional units called osteons
(concentric circles with central canal)

Matrix - hard and calcified with many collagen
fibers

Cells - osteocytes in lacunae within matrix

Function: protection, support, and storage of
minerals

Location: skeleton
Subtype: Osseous (Bone), Specific Type: Spongy

Spongy (Cancellous) bone

Interior to and continuous with compact bone

Numerous trabeculae (branching bony plates) with
interconnecting spaces. The space are filled with
marrow

Matrix - hard and calcified with many collagen
fibers but lacks bone lamellas.

Cells - osteocytes in lacunae within matrix

Function – protection, support, storage of bone
marrow
Subtype: Blood

Make up of formed element (blood cells) and
plasma (fluid)

Matrix - plasma- fluid

Cells - Blood cells –erythrocytes (red blood cells),
leukocytes (white blood cells), thrombocytes
(platelets, cell fragments)

Fibers are only present during clotting

Function: transport of oxygen, waste, nutrients and
hormones, aids in regulation of body temp,
maintains homeostasis by buffering tissue
Nervous Tissue
Nervous System
 Transmit information
 Cells
 Neurons - nerve cell bodies (soma) with dendrite
and axon processes, major cell type
 Supporting cells - non-conducting support cells