Connective tissue

The term connective tissue is applied to a tissue which fills the interstices between more specialized elements; and serves to hold them together and support them.

CONNECTIVE TISSUE:

- GENERAL

- SKELETAL

GENERAL CONNECTIVE TISSUE:
CONNECTIVE TISSUE POSSESSING SPECIAL PROPERTIES:
- Mucoid (mucous) tissue	This kind of tissue is found in the umbilical cord. The most conspicuous component of mucoid tissue is a jelly like ground substance rich in hyaluronic acid.
- Adipose tissue	An aggregation of fat cells (adipocytes). Each fat cell contains a large droplet of fat that almost fills it.
- Pigment tissue	Pigment cells that are easily distinguished as they contain brown pigment (melanin) in their cytoplasm.
- Reticular tissue	Stellate cells that have long cytoplasmic extensions which join with those of other cells.
FIBROUS CONNECTIVE TISSUE:
- Dense connective tissue:	It contains many fibres and few cells.
1. regular	Bundles of fibres are arrenged parallel to one another in a very orderly manner.
2. irregular	Bundles of fibres interlace in various directions.
- Loose connective tissue	It contains many cells and few fibres.

FIBROUS CONNECTIVE TISSUE
CELLS:
- Fibroblasts	These are the most numerous cells of connective tissue. They produce intercellular substance. They are large and immovable.
- Histiocytes (macrophage cells)	They are small and movable. They have the ability to phagocytose unwanted material.
- Pigment cells	Cells that contain brown pigment melanin in their cytoplasm.
- Fat cells (adipocytes)	Cells that contain droplets of oil.
- Mast cells	Cells that release histamine. Release of histamine is associated with the production of allergic reactions.
- Plasma cells	Cells that produce antibodies.
- Lymphocytes	Cells that emigrate to connective tissue from the blood stream.
INTERCELLULAR SUBSTANCE
- Ground substance	Glycosaminoglycans and glycoproteins.
- Fibres:
1. collagen fibres	They are arranged in bundles. Collagen fibres are thick, they can resist considerable tensile forces (i.e. stretching) without significant increase in their length.
2. elastic fibres	They are thin.They run singly (not in bundles), branch and anastomose with other fibres.
3. Reticular fibres	These fibres are a variety of collagen fibre (type III).

SKELETAL CONNECTIVE TISSUE:
CARTILAGE:
- Hyaline cartilage	It represents transparent cartilage, the homogenous intercellular substance of which contains many collagenous fibres. In the zone of the young cartilage (just under the perichondrium) chondrocyters are flattened and are present singly. Towards the centre of a mass of hyaline cartilage the chondrocytes are large and are usually present in groups (isogenous groups).
- Elastic cartilage	It is similar in many ways to hyaline cartilage. The main difference is that the intercellular substance contains both collagen and elastic fibres. It is less transparent than hyaline cartilage.
- Fibrocartilage	It is not transparent. The cells are arranged in short rows.
BONE
DENTIN OF TOOTH
CEMENT OF TOOTH

Дата добавления: 2015-10-30