Connective Tissue and Bone Flashcards
Connective Tissue
- Loose Connective Tissue:
- Fibrous Connective Tissue
- Bone
- Adipose Tissue
- Cartilage
- Blood
Connective Tissue
Cell Type:
- fibroblast
- chondroblast
- osteoblast
Extracellular matrix (ECM):
- structural fibers
- collagen fibers
- reticular fibers
- elastic fibers
- specialized proteins - Ground substance
Fibroblasts
When activated, they produce and secrete the CT fibers and ground substance
- Repair wounds
- Long, thin dark lines under (inactive) to purple multi-nucleated ovals
Macrophages
- Phagocytes - scavenging cells
- Indented, bean shaped nuclei
- EM - evidence of phagocytic activity
- abundant rER, sER, golgi, and lysosomes
Other Connective Tissue (CT) cells
Leukocytes (WBCs):
- lymphocytes
- mast cells, plasma cells, basophils
- Natural Killer Cells
Adipocytes:
- shown as white
- accumulate fat
- make up adipose tissue
Connective Tissue Fibers
Collagen Fibers (most abundant):
- flexible, high tensile strength
- Type I collagen - collagen fibrils
Elastic fibers (thinner):
- composed of elastin and fibrillin
Reticular Fibers (Type III collagen):
- Found at interface of connective tissues and epithelium
- Indicate tissue maturity - wound healing
Collagen Fiber
- microscopic ropes
- transmit tension
Elastin fibers
cross-linked
Connective Tissue Ground Substance
- Gel-like extracellular matrix
- Glycosaminoglycans (GAGs): very negative charged long chains of sugar that attract water generating the gel
- Hyaluronic acid: rigid, >1000 sugar long chain which binds to proteogylcan aggregates:
- abundant in cartilage
- shock absorbing
- binds to growth factor and signaling molecules
- Proteoglycans (large macromolecules composed of a core protein) link to GAGs
Types of connective tissue
Connective Tissue Proper:
- loose connective tissue
- dense connective tissue (regular or irregular)
Specialized connective tissue:
- cartilage
- bone
- blood
- hemopoietic tissue
- lymphatic tissue
Loose Connective Tissue
- Cellular connective tissue with few collagen and elastin fibers
- “ground substance” - specialized medium for diffusion - nutrient O2, CO2
- Locate beneath the surface of almost all of the bodies epithelium
- Cell Types: fibroblasts (flat nuclei), macrophages (bean-shaped), adipocytes, other immune cells: lymphocytes (round nuclei)
- Where blood vessels and nerves go through to get to organs
Location: intestines, lamina appropri - sites of inflammation (influx of cells to fight)
Dense Irregular Connective Tissue
- Reduced # of cells (fibroblasts)
- abundant thick irregularly arranged collagen fibers
- Found in regions of stretch
- Resistant to tearing and excessive stretching
- Found in mammary glands
Microscope:
vein and capillary: circle with red
Dense Regular Connective Tissue
Found in tendons (have tendinocytes) (muscle-bone) and ligaments (bone-bone)
- few cells - mostly fibroblasts
- collagen fibers arranged in parallel
Tendonitis
- disordered collagen arrangement
- increased proteoglycan ground substance
- neovascularization: formation of new microvascular systems, increased blood flow, inflammation
Tendons
Has tendinocytes
- Epitendinium: connective tissue capsule surrounding
- Endotendinium: subdivides tendon into fascicles (containing vasculature)