Connective Tissue Flashcards
Functions of connective tissue.
major structure, connectivity and support; hormonal-induced cell growth and differentiation; nutrient and metabolic wastes exchange, temperature, salinity (most abundant tissue in the body)
Components of connective tissue.
Cells
Fibers
Ground Substances (heterogeneous): GP’s, GAG’s, & PG’s
Extracellular matrix
Protein Fibers: Collagen, Reticular, Elastic
Different protein fibers are associated with different connective tissue cell types
- Hyaline cartilage is very well hydrated
Fibroblasts/fibrocytes
- Synthesis of collagen, elastin, PG’s, GP’s & extracellular cell components
- Undifferentiated cells until exposed to environment with particular growth factors, in which they will mature into fibrocytes (happens to osteoblasts too)
- Represented in all tissues except adipose tissue
What type of cells are chondrocytes/blasts in the cartilage?
fibroblasts/fibrocytes
This type of cell is found in tissue with alot of filtration.
Collagen Type III
This type of cell is found in highly vascularized tissues.
reticular fibers
Differences between fibroblasts and fibrocytes.
Fibroblasts: The nucleus is large, load of mitochondria, elongated golgi apparatus, have alot of transcription taking place with little chromatin being condensed. In blast form the DNA activity is very high, but in the cytes the nucleus is condensed.
Fibrocytes: has minimal functionality because most of the DNA is coiled, allow for little transcription and decreasing cell metabolism (space saving cells)
Derived from hematopoietic pluripotential cells in RBM.
macrophage
Are classified based upon their location; Liver: Kupffer, Bone: Osteoclasts, Skin: Langerhans Cells etc.
macrophage (monocyte)
Manage the bone calcium metabolism of the body.
osteoclasts
Mast cells
Store chemical mediators to inflammatory responses
Two types:
a. CT-skin, peritoneum
b. Intestinal mucosa & lungs
Contain basophilic metachromatic secretory granules-locally paracrine (Heparin/chondroitin sulfate - mucosal, Histamine, Proteases, ECF-A, SRS-A - leukotriene).
mast cells
- Arise from B lymphocytes
- secondary function is connective tissue
- Present in CT assoc. with wet epithelia and Lymphoid Tissue
- Synthesize Ig’s (antibodies)
plasma cells
Adipocytes
- Storage of neutral fats/heat production
- Everywhere in connective tissues except joint capsules
- One of the most abundant cells in the body
Eosinophil
- Large granules, containing bioactive substance for antiparasitic agents & histamine
- mediate inflammatory responses due to allergic reactions in a weak way
= Linked bilobed, sausage -shaped nucleus
Basophils
- Dense, dark, large granules (Large allergic reaction response)
- Bilobular but NOT polynucleated!
Lymphocytes
- respond to viral infections
- Specialty of lymphocytes: responding to inflammatory response
Type T and Type B cell types
T: acquired immunity cells that are found in the lymph – learn antigens in the thymus during childhood and adolescence
B: innate immunity; produce faster, antibodies
- Small cytoplasmic granules
- Linked Polynucleated & lobulated nucleus
- Respond to bacterial infection
- Polylobulated (over five lobules is pathological)
Neutrophil
WBC chemotaxis emigration is achieved through what?
Diapedesis
kamikazee cells!!
Once the cell goes through into the interstitial fluid it cannot go back, it will die at site of inflammation.
Neutrophil life span = 4-6 hours; body gets rid of it after this process
The neutrophils will die faster and chances to die are higher because they are the first cells sent out in any immune response.
Meshwork-forming fibrils:
collagen type IV (structural-BL); most complex because they allow multiple interactions of biochemical agents → highly reactive; associated to the basement membrane (only the basal lamina component)
Long fibrils:
collagen types I (everywhere in the body that is collagen based, most abundant), II (wherever there is type I, usually there is type II), III, V, XI
Short connecting fibrils:
collagen types IX, XII, XIV,XVI,XIX,XX,XXI (FACIT’s)
Hexagonal network-forming:
VIII, X
Transmembrane:
XIII, XVII (hemidesmosomes), XXIII, XXV