Connective tissue serves as supporting tissue in the body, composed of cells, fibers, and ground substance, with extracellular matrix as the major component. Key cell types include fibroblasts, macrophages, plasma cells, and adipocytes, while the main fiber types are collagen, reticular, and elastic fibers. Different types of connective tissue, such as loose, dense, adipose, and specialized tissues like bone and cartilage, fulfill various functions including support, protection, and energy storage.

1. CONNECTIVE TISSUE

2. • It’s the supporting tissue.
• It fills the intersticium, capsulate organs, connect organ
parts and maintain them in a relative position.

3. Structure
• connective tissue is formed by three classes of
components:
• Cells.
• Fibers.
• Ground substance.
• The major constituent of connective tissue is the
extracellular matrix .

4. Cells of connective tissue
• Fibroblasts: Secrete both fibers and ground substance
of the matrix.
• Macrophages: Phagocytosis(defense)
• Plasma Cells: Antibody secreting cells that develop
from B Lymphocytes.
• Mast Cells: Produce histamine that help dilate small
blood vessels in reaction to injury .
• Adipocytes: Fat cells that store triglycerides, support,
protect and insulate .
• Others esinophils, lymphocytes,

5. Extracellular Substance
Ground
substances
fibers

6. Connective tissue fibers
• Collagen fibers
• the dominant fiber type. The primary function of collagen fibers is
to add strength to the connective tissue.

7. • Reticular fibers
• very delicate branched fibers and form fine networks instead of
thick bundles.
• Only seen when using special stains e.g. silver stain.
• constitute a network around the parenchymal cells of organs
especially the hematopoietic(blood forming) organs (eg, spleen,
lymph nodes, red bone marrow.

8. • Elastic fibers
• Thinner than collagen fibers and made of protein elastin
• Branched fibers.
• allow stretch and recoil.

9. Ground substance
• is a highly hydrated, transparent, complex mixture
of macromolecules.
• It fills the space between cells and fibers of
connective tissue and acts as a lubricant and a
barrier to the penetration of invaders.
• e.g. Hyaluronic Acid, Chondroitin sulfate,
Dermatin sulfate, keratin sulfate, and adhesion
proteins

11. Types of connective tissue
C.T.
proper
Special
(adipose, bone
and cartilage)

12. proper
Fibrillar
Loose Dense
Reticular Elastic

13. Loose connective tissue(Areolar)
• consists of all 3 types of fibers, several types of cells, and semi-
fluid ground substance
• found in subcutaneous layer and mucous membranes, and around
blood vessels, nerves and organs
• It supports organs under low pressure and friction.

15. Dense C.T.
• contains more numerous and thicker fibers and far fewer
cells than loose CT
• Of 2 types, regular and irregular

16. dense regular Connective Tissue
• consists of bundles of collagen fibers and fibroblasts.
• The fibers are arranged in regular bundles.
• forms tendons, ligaments and Aponeuroses
• Function = provides strong attachment between various
structures.

19. Dense Irregular CT
• consists of randomly-arranged collagen fibers and a few
fibroblasts
• Found in fasciae, dermis of skin, joint capsules,
periostium.
• Function = provide strength

21. Reticular CT
• Consists of fine interlacing reticular fibers and reticular
cells
• It forms the structural framework(stroma) in which the
cells of the organ are suspended
• Found in liver, spleen and lymph nodes

23. Elastic connective tissue
• Contains elastic fibers.
• The elastic fibers usually branch , anastomose, and don’t
form bundles unlike the collagen fibers.
• Provide resilience e.g. ligamentum nuchae.

25. Adipose tissue
• consists of adipocytes; "signet ring" appearing fat cells
found separately or within loose connective tissue.
• it represents 15–20% of the body weight and 20–25%in
women.
• found in subcutaneous layer, around organs and in the
yellow marrow of long bones
• function = supports, protects and insulates, heating and
serves as an energy reserve.
• .

26. • There are 2 types of adipose tissue
• Unilocular Adipose Tissue
• Multilocular Adipose Tissue

27. Unilocular Adipose Tissue
• It is color varies from white to dark yellow (carotenoids
dissolved in fat droplets.
• represents all adipose tissue in adults is of this type.
• Its distribution is regulated by sex hormones and
adrenocortical hormones.

28. • cells are spherical and closely packed in adipose tissue.
• cell measures 50 and 150µm in diameter.
• cell appears as a thin ring of cytoplasm surrounding the
vacuole left by the dissolved lipid droplet and eccentric
and flattened nuclei (signet ring).
• The cytoplasm surrounds the nucleus contains a Golgi
complex, mitochondria, poorly developed cisternae of the
rough endoplasmic reticulum

30. • Unilocular adipose tissue is subdivided into incomplete
lobules by highly vascular connective tissue .
• Adipose tissue can synthsize and secrete leptin which
participates in the regulation of the amount of adipose
tissue in the body and in food ingestion.
•

32. Multilocular Adipose Tissue
• Also called brown fat ( due to both the large number of
blood capillaries and the numerous mitochondria).
• In humans it is important mainly in the first months of
postnatal life as heat producer and protects the newborn
against cold.

33. • cells are polygonal and smaller than cells of unilocular
adipose tissue and chatacterized by :.
• The cytoplasm contains a great number of lipid droplets of various
sizes
• spherical and central nucleus
• numerous mitochondria with abundant long cristae.