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Connective Tissue, Specialized Tissue and Repair
Biology 2121Chapter 4
Characteristics of Connective Tissue • General Characteristics
– Less cellular; nonliving part
– Vascular (exception is cartilage)
– Innervated – Functions
• Protection and insulation (organs)
• Binds tissues – ligaments • Transports vital substances
(blood) • Stored energy source (adipose
tissue) • Supports epithelial tissue
• Stem Cell – Mesenchyme– All CT cells originate
CT Stem Cell
• Stem Cell – Mesenchyme– All CT cells originate from
this embryonic stem cell
• Each type of CT has a specific ‘main’ cell type – Secretes the matrix – Maintains the tissue
General Characteristics - Structure 1. Less Cells- More
Matrix• Refers to the “non-
cellular” part of connective tissue
2. Fibers, water, organic molecules, acid
3. Other cell types– May or may not be
present – Mast cells; macrophages;
adipose cells; plasma cells
The Matrix • Composed of ‘ground
substance’ and ‘fibers’
1.Ground Substance – Between cells and fibers– Water – Organic molecules –
‘Glycosaminoglycans’ (GAG’s)• Protein core (proteoglycans) with
GAGs attached • Chondroitin sulfate; keratan
sulfate; Hyaluraonic acid
2. Function of the Ground Substance– Water storage; binds and
supports cells; tissue development
Fibers • 3. Fibers
– (a). Collagen – found in bone, cartilage, tendons, ligaments• Fibrous Protein
– (b). Elastic – ‘elastin’ protein; stretch and contract; found in skin, BVs, lung tissue
– (c). Reticular – fine collagen bundles; thin; support spleen and lymph structures; forms part of basement membrane
Classification of Connective Tissue
Dense CT
• Dense CT – 1. Regular Dense CT– 2. Irregular Dense CT
Classification of Connective Tissue
Classification of Connective Tissue
Specialized Tissue - Membranes • Parts of the body are
covered by ‘membranes’ which are composed of several different types of tissue
• Connective Tissue bound to Epithelial Tissue
• Examples: – 1. Cutaneous
membranes – 2. Mucous membranes – 3. Serous membranes
Specialized Tissue - Membranes
Injury and Repair of Tissue • Ability to Repair
– 1. Epithelium, bone, CT proper, dense irregular, blood regenerates well
– 2. Smooth muscle and dense regular regenerate moderately well
– 3. Skeletal muscle and cartilage repair but poorly
– 4. Cardiac and nervous tissue (none) • Fibrous scar tissue
• Depends on: – Supporting CT ability produce new cells– Functioning organ and tissue ability to produce
new cells
Tissue Repair • Begins with Inflammation
– Capillaries dilate; tissue inflamed• Dying cells/tissue release
chemicals
– WBCs, macrophages, platelets enter
• Granulation – New collagen develops; BVs
branch to all parts of injured tissue
– Connective tissue grows – ‘granulation tissue’ across the wound
– SCAB and Tissue Regeneration
• Fibrosis