CONNECTIVE TISSUE

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CONNECTIVE TISSUE

• The Major Structural Constituents of The Body

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Tissue A Definition
A group of connected, interdependent cells that
cooperate to perform a specific function
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Categories of Tissue
1. Epithelial Tissue 2. Connective Tissue 3.
Muscle Tissue 4. Nervous Tissue
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Function of CT

• Responsible for providing and maintaining form in
  the body.
• Provide a matrix that connects and binds cells
  and organs and ultimately supports body.

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Components of CT

• Cells
• Extracellular matrix
• Fibers
• Collagenous, reticular, elastic
• Ground substance
• Hydrophilic macromolecules (glycoproteins,
  glycosaminoglycans, proteogycans) bind to
  receptors on cells and add strength and rigidity
  to matrix

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CT Cells

• Fibroblasts
• Synthesis of all fibers, ground substance.
• Mast cells
• Contain granules with histamine, heparin,
  leukotrienes.
• Macrophages
• Phagocytosis
• Plasma cells
• Derived from lymphocytes, produce antibodies.
• Originate from hematopoietic stem cells in bone
  marrow, circulate in blood, move to CT where they
  remain and perform their functions

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Fibroblasts
Synthesize collagen, elastin and macromolecules
of ground substance. Rarely rarely
undergo division.
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Fibroblasts (inactive)
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Collagenous Fibers

• Collagenous
• Most common protein in the body (30 of dry
  weight)
• Stain pink
• Make up mesenteries, tendons, cartilage,
  ligaments, lamina propria, every organ.

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Collagenous Fibers(Dense Irregular CT)
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Reticular CT(Adrenal Cortex)
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Reticular Fibers

• Reticular
• Are not stained by HE, stain black with silver
• Very delicate hold cells together in organs.
• Provide framework for spleen, lymph nodes, red
  bone marrow, liver, endocrine glands.
• Makes flexible network in arteries, intestinal
  muscle layer, uterus

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Reticular Fibers
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Elastic Fibers

• Stretchable, highly resistant to pulling forces.
• Found in arteries, cartilage, mesenteries

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Extracellular Matrix

• Fibers
• Collagenous (collagen)
• Reticular (collagen)
• Elastic (elastin)
• Amorphous ground substance
• Gel-like matrix in which fibers, cells are
  embedded and through which fluid diffuses.
• Tissue fluid

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Reticular CT
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Collagen, Elastic Fibers(Areolar CT)
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ADULT CT

• CT proper
• Loose
• Reticular
• Adipose
• Dense irregular
• Dense regular
• Collagenous
• Elastic

• Specialized CT
• Cartilage
• Bone
• Blood

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Loose (Areolar) Conn Tissue

• Structure
• Many cells
• Jello-like matrix
• Collagen elastic fibers

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Binding Tissue

• Function Binds organ parts together
• Sample Locations Skin, kidney, lungs

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Loose CT
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Elastic, Reticular Fibers
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Dense Irregular CT
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Dense Irregular CT
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Section of rat skin. The subepithelial
connective tissue (dermis) is loose connective
tissue. In this area, the cells, most of which
are fibroblasts, are abundant. The deepest part
of the dermis consists of dense irregular
connective tissue, which contains many randomly
oriented thick collagen fibers, scarce ground
substance, and few cells. HE stain. Medium
magnification. (Courtesy of TMT Zorn.)
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Elastic Connective Tissue
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Dense Regular C T

• Structure
• Few cells
• Dense matrix
• Aligned collagen fibers

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DENSE CT