HISTOLOGY 1.6.: CONNECTIVE AND SUPPORTIVE TISSUES
CLASSIFICATION OF CONNECTIVE AND SUPPORTIVE TISSUES
I. Embryonic connective and supportive tissue
• Mesenchyme
• Gelatinous connective tissue
• Chordoid tissue
II. Adult connective and supportive tissues
Adult connective tissues
1. Loose connective tissue
2. Dense irregular connective tissue
3. Dense regular connective tissues
Collagen
Elastic
4. Reticular connective tissue
5. Adipose tissue
White adipose tissue
Brown adipose tissue
Adult supportive tissues (see later)
Embryonic connective tissues
Mesenhyme
Three-dimesional network of irregular-shaped cells + abundant ground
substance (no fibers).
Function: gives rise to various types of adult connective tissue
Occurrence:
• Body of embryo
• In the adult
around blood vessels
Embryonic connective tissues
Gelatinous connective tissue
Tissue components:
Stellate fibroblasts,
amorphous ground substance
collagen fibrils
Cross-section of the
umbilical cord
Occurrence in adult:
Omasal laminae
Bovine glans penis
Core of rooster comb
Embryonic supportive tissue
Chordoid tissue
1
2
3
1. Cross-section fo an embryo. The arrow points at the notochord
2. Cross-section of the notochord
3. The chordoid tissue in a young notochord composed of large polygonal cells
ADULT CONNECTIVE TISSUES:
Loose connective tissue
The most widely distributed type of CT
Present around blood vessels and nerves, between muscle bundles,
beneath epithelia, in pia mater and arachnoidea
Functions:
support, dampening
tissue repair, defence activities
Tissue components:
free and fixed cells (dominating, see before)
collagen, elastic and reticular fibers
ground substance
ADULT CONNECTIVE TISSUES
Dense irregular connective tissue
Collagen fibers are the most abundant tissue components arranged
in bundles crossing each other at various angles.
From among cell types fibroblasts and fibrocytes predominate.
Occurrence:
aponeuroses, muscular fascia, capsules of organs,
dermis, pericardium.
ADULT CONNECTIVE TISSUES:
Dense regular connective tissue
The fibers are arranged in the same plane and direction
Occurs in collagen tendons and elastic ligaments
Collagen tendon longitudinal section. Arrows point at
elongated nuclei of tendocytes. H.E. staining
Elastic ligament longitudinal
section. Resorcin-fuchsin
staining
Elastic ligaments:
Ligamentum flavum (see above)
Ligamentum nuchae
Elastic fasciae of abdominal
musculature of herbivores
ADULT CONNECTIVE TISSUE
Reticular connective tissue:
forms the stroma fo all lymphatic organs (spleen,lymph node,
hemal node, tonsils, etc.)
Tissue components:
Stellate reticular cells + complex three-dimensional network
of reticular fibers
ADULT CONNECTIVE TISSUES
Adipose tissues:
Specialized to multiple functions
White adipose tissue: unilocular adipocytes + collagen and reticular fibers
Functions:
thermal and mechanical insulation,
dampening (digital pads)
stored energy source
hormone-production (leptin)
ADULT CONNECTIVE TISSUES
Brown adipose tissue: multilocular adipocytes (lot of
mitochondria) + collagen and reticular fibers
Function: non-shivering thermogenesis
Occurrence: in newborns,
rodents and hibernating animals
(axillary and neck region,
interscapular fat, thoracic aorta,
mediastinum, mesenteries,
vena cava dorsal to kidney)