Exam 3: Connective Tissue, bone and cartilage Flashcards
Where is connective tissue (CT) found?
In every organ system except the CNS
Characteristics of CT
*Relatively few cells *Abundant matrix *Matrix contains varying amounts of protein fibers * CT is typically classified on the basis of the type of MATRIX, FIBER DENSITY, and FIBER ORGANIZAITON
List the FIVE functions of CT
- Physically supports other tissues 2. Binds tissues together 3.Provides structural framework and opposes gravity 4. Helps to create body CONTOURS 5. Houses Specialized tissues, (i.e): -Blood forming tissues (hematopoietic) -Lymphoid Organs
What are the Three types of of CT?
- Embryonic CT 2. Adult CT -Loose -Dense 3. Special
What are the characteristics of LOOSE ADULT CT?
*high ratio of fibroblast to fibrous components *type I collagen *usually found beneath epithelial tissues of most organs
What are the characteristics of DENSE ADULT CT?
*High Ratio of fibrous components to fibroblast *thicker bundles of collagen than in loose CT *No specific orientation of collagen bundles in dense irregular dense CT *highly ordered bundles of collagen in dense regular CT
What modalities can be associated with Adult CT?
Reticular and Elastic
What modalities can be associated with Special CT?
adipose, cartilage, bone, hematopoietic
Give the location and Function of Type I collagen fibers
General CT and BONE; Tensile strength.
List the steps of Collagen fiber synthesis
- Type I collagen is synthesized as a prePROpeptide 2.The signal (pre-) sequence is cleaved after translocation of the polypeptide into the endoplasmic reticulum (ER) lumen 3.Pro-collagen molecule c̅ terminal non-helical ends (secreted into extracellular matrix by fibroblasts) 4. Terminal non-helical ends are cleaved into form tropoCOLLAGEN. (tropocollagen spontaneously assembles into staggered arrays to for collagen fibers c̅ characteristics 64 nm banded pattern) 5. BOOM collagen
List the steps of elastic fiber synethesis
- Elastin is also synthesized as a prePROprepitde 2.secreted as a propeptide 3. converted to tropoelastin 4.Assembled into amorphous fibers or sheets c̅ the aid of fibrillin
What are the principal cell types found in CT?
Fibroblasts and Fibrocytes; they are also the most numerous
Functions of Fibroblasts and Fibrocytes:
secretion and maintenance of CT matrix secrete precursor fibrous molecules secrete the amorphous components of the matrix, including the glycosaminoglycans.
What are Glycosaminoglycans?
GAGS are large, negatively charged polysaccharides consisting of repeated disaccharide units.
What are the four groups of GAGS
Hyaluronic Acid Heparin and Heparan Sulfate Chondroitin sulfate and Dermatan Sulfate Keratan Sulfate
Where is hyaluronic acid found
cartilage, skin, synovial fluid, and general CT
Where is heparin and heparan sulfate found?
basement membrane, skin, lung, liver, blood vessels, mast cell granules
Where are chondroitin sulfate and dermatan sulfate found?
cartilage, bone, skin, blood vessels, heart, cornea
Where is Keratan Sulfate found?
Cartilage, cornea, and intervertebral disk
What are the common type of resident cells in fibrous CT?
macrophages, mast cells, plasma cells.
What are three types of macrophages?
Monocytes, kupffer cells, microglial cells.
mast cell characteristics:
stain with toluidine blue Large metachromatic granules with histamine and heparin Involved in hypersensitive response to allergens.
Plasma Cell characteristics:
Activate B lymphocytes Large pale nuclie with “clock-face” distribution of chromatin Prominent Golgi
Define carcinoma in situ
tumor cells that have not invaded the basement membrane and remain confined within the epithelial layer.
Define Microinvasive carcinoma
decrease in cadherins, basement membrane breaks down. Collagenase IV breaks down BM allowing tumor cells to invade the subjacent CT
Define Invasive Carcinoma
They secrete: 1. Autocrine Motility Factors 2. Vascular premeability factors 3. Angiogenic factor this can lead to metastasis
Where are adipocytes derived from?
undifferentiated mesenchymal cells and are distinguished by their unique appearance.
What are the two types of adipocytes?
- White fat is distributed throughout the body - unilocular (one fat drop) 2. Brown fat cells contain numerous smaller lipid droplets -multilocular -slightly more cytoplasm -abundant mitochondria, which give them their brown coloration
Identify the following Tissue
adult CT: Reticular Tissue
Identify the following tissue:
Adult CT: elastic Tissue