Chapter 4 Part 2 Flashcards
Connective Tissue (Functions and Types)
-Functions of CT) Include binding, support, protection, insulation, sotoring reserve fuel, and transporting substances (blood)
-Four Main Classes Connective Tissue Proper Cartilage Bone Blood
Three Characteristics of Connective Tissue.
1) All have common embryonic origin) CT comes from tissue called mesenchyme
2) Degrees of Vascularity) range from avascular to very vascular.
3) Have Extracellular Matrix
Components of the Extracellular Matrix
- Ground Substance
- Fibers
- Cells
Ground Substance
-Unstructured material that fills the space between the cells and contains fibers.
Three components)
- Interstitial Fluid) Fluid Between Cells
- Cell Adhesion proteins) Glue for cell attachment
- Proteoglycans) Sugar proteins which can trap water. Affect viscosity of the matrix.
Two Types of CT cells (based on cell maturity)
Blast Cells) Baby Cells. Immature form of a cell that actively secretes ground substance and ECM fibers.
Cyte Cells) Mature Cells. Less active than Blast Cell. Maintains the health of the matrix.
Main Types of CT Cells
Fibroblasts/cytes) Found in connective tissue proper
Chondroblasts/cytes) found in Cartilage
Osteoblasts/cytes) Found in Bone
Blood) Exception. Immature cells are found in bone marrow.
Other Connective Tissue Types
- Fat Cells) Stores nutrients
- White blood cells) Tissue response to injury
- Mast Cells) Initiate local inflammatory response. secrete chemicals such as heparin (regulates other chemicals), histamine (makes capillaries leaky), proteases and other enzymes.
- Macrophages) Eat dead cells and microorganisms.
Connective Tissue Proper
-All connective tissue except bone, cartilage, and blood
Two types
- Loose Connective Tissue) Arelolar, Adipose, and Reticular.
- Dense Connective Tissue) Dense Regular, Dense Irregular, Elastic.
Loose Areolar Connective Tissue
- Most widespread CT.
- Supports/Binds other tissues (and Organs). Holds Body Fluid/ Fat. Defend against infection.
- Fibroblasts secrete mostly collagen fibers. These fibers are loose which means there is more ground substance.
Loose Adipose Connective Tissue.
- Cells are Adipocytes (fat cells). More Cells than Ground Substance. Nucleus appears pushed to the side. Two types
- White Fat) Nutrient Storage. Cells are tightly packed (little matrix). Very Vascular. Absorb Shock, insulate, and store energy
- Brown Fat) Uses its lipids rather than ATP to heat the bloodstream.
Loose Reticular Connective Tissue.
- Resembles areolar tissue but the fibers are thinner reticular fibers (thin collagen fibers).
- Fibroblast cells are called Reticular Cells they Secrete the reticular fibers
- Form a mesh like Stroma (skeleton) that acts as support for blood cells in lymph nodes, spleen, and bone marrow.
Dense Regular Connective Tissue.
- High Tensile Strength; can stretch and withstand tension.
- Made of closely packed thick collagen fibers. Fibers are wavy and parallel to each other. Fibers/ Ground surface are made by fibroblasts.
- Poorly Vascularized.
- EX: Tendons, Ligaments, Aponeuroses (Flat, sheetlike tendons that attach muscle to muscle or bones)
Dense Irregular Connective Tissue
- Same Elements as Regular CT, but bundles of collagen fibers are irregularly arranged.
- Means it resists tension from many directions.
- EX: Dermis, Fibrous joint capsules, Fibrous coverings of some organs.
Elastic Connective Tissue
- Contains Elastic Fibers.
- Found in artery walls which need to stretch
- Some ligaments like those in the vertebrae are very elastic.
Cartilage
- Chondroblasts) grow new cartilage. They produce a new matrix until the skeleton stops growing at the end of adolescence.
- Chondrocytes) Mature Cartilage Cells. Found in cavities called lacunae.
- 80% Water. Made of tough collagen fibers and sugar proteins
- Lacks Nerve Fibers and is Avascular. It receives nutrients from perichondrium (makes chondroblasts/cytes)
