Histo Lab - Lecture 4 (Connective Tissue Proper) PDF

1/4/25 4 MAIN GROUPS Connective Tissue Proper...

1/4/25 4 MAIN GROUPS Connective Tissue Proper Bone Cartilage Blood HUMAN HISTOLOGY MICROSCOPIC EXAMINATION of CONNECTIVE TISSUES 1 2 CONNECTIVE TISSUES ORIGIN OF CONNECTIVE TISSUES Most diverse group of tissues Mesenchyme Supports and binds tissues for all organs Loose and fluid type of embryonic tissues Common origin of all connective tissues Mesenchymal cells – can be situated in any way and can move from place to place. Unlike the Epithelial cells which have fixed and neatly arranged in sheets 3 4 CHARACTERISTICS COMPONENTS Extracellular Matrix Different degrees of vascularity (blood flow) Non-living component of connective tissues Cartilage – avascular Inert matrix Dense irregular tissue in skin – vascular 1. Ground Substance Its cells are separated by a large amount of Intercellular space 2. Fibers 5 6 1  1/4/25 GROUND SUBSTANCE FIBERS Watery, rubbery, unstructured material that fills the spaces Provide support and structure to the otherwise shapeless ground between cells. substance Protects the cells in the extracellular matrix 1. Collagen – strongest and most abundant type, tough and flexible. Flexible – made of starch, protein molecules and water 2. Elastic Fibers – longer and thinner which form a branching framework within the matrix. Proteoglycans – anchors this framework Made of protein elastin – allows them to stretch and recoil GAG or Glycosaminoglycans – sprouts from proteoglycans Found in the skin, lungs and blood vessel walls 3. Reticular Fibers Short, finger collagen fibers with an extra coating of glycoprotein. Forms a delicate, sponge-like networks that cradle and support the organs. 7 8 CELLS Blasts Literally means “forming” Stem cells or immature cells Undergoes mitosis to replicate themselves Has different types with different functions Once they mature they transition from –blast to –cyte* Chondroblast – blast cells of cartilage Osteoblast – blast cells of the bone tissue Macrophages – provide immune defense for connective tissues, phagocytize bacteria, foreign materials and dead cells 9 10 COLLAGEN FIBERS Strongest and most abundant type of fiber Appears neat and smooth “white, flexible” structures under the microscope Provides great resistance to tension 11 12 2  1/4/25 ELASTIC FIBERS RETICULAR FIBERS Form a branching framework Short, finer collagen fibers Stretch and recoil like rubber bands Sponge like networks 13 14 CONNECTIVE TISSUE PROPER Most diverse group in the tissue family Loose Connective Tissue 1. Areolar 1. CONNECTIVE 2. Adipose 3. Reticular TISSUE PROPER Dense Connective Tissue 1. Regular 2. Irregular 3. Elastic 15 16 LOOSE CONNECTIVE TISSUE Have fewer fibers, and more cells and more ground substance. 1. Mesenchyme – embryo, fetus 2. Mucoid – Wharton’s jelly or umbilical cord 3. Adipose – subcutaneous tissue (dermis) 4. Reticular – bone marrow, lymph node, spleen 17 18 3  1/4/25 DENSE CONNECTIVE TISSUE CONNECTIVE TISSUE PROPER Tendon 1. Regular – tendon, stroma of cornea Dense connective tissue 2. Irregular – dermis, capsules of organs Connects your bone to muscle and muscle to muscle Ligament Dense connective tissue Connects your bone to bone 19 20 LOOSE CONNECTIVE TISSUE PROPER LOOSE CONNECTIVE TISSUE PROPER Areolar Connective Tissue Areolar Connective Tissue Most common loose connective tissue It has loose and random arrangement of fibers Found all over the body Few fibroblast cells Under the epithelial tissues and wrapped around the organs Has a lot of open space 21 22 LOOSE CONNECTIVE TISSUE PROPER Areolar Connective Tissue Is effective in holding the watery, salty ground substance “Sponge” for watery ground substance 23 24 4  1/4/25 LOOSE CONNECTIVE TISSUE / LOOSE CONNECTIVE TISSUE PROPER AREOLAR CONNECTIVE TISSUE Adipose Connective Tissue Fat tissue 25 26 ADIPOSE TISSUE LOOSE CONNECTIVE TISSUE PROPER The average person’s weight is about Adipose Connective Tissue 18% adipose tissue or fat stores Is not mostly ground substance Provides insulation against heat loss Is mostly cells – adipocytes – which store lipids for later use Provides fuel storage and keeps us alive during starvation or fasting 27 28 ADIPOSE TISSUE 29 30 5  1/4/25 LOOSE CONNECTIVE TISSUE PROPER LOOSE CONNECTIVE TISSUE PROPER Reticular Connective Tissue Reticular Connective Tissue Holds your blood cells in place in many of the blood forming organs. Provides the soft internal framework or stroma of the spleen, lymph nodes and bone Similar to areolar tissue but with a woven mass of reticular fibers instead of collagen and marrow elastin fibers Supports developing blood cells and holds your blood in place inside the organs 31 32 RETICULAR TISSUE 33 34 DENSE CONNECTIVE TISSUE PROPER Regular Dense Connective Tissue Collagen fibers are stacked neatly in regular rows 35 36 6  1/4/25 REGULAR DENSE CONNECTIVE TISSUE DENSE CONNECTIVE TISSUE PROPER Irregular Dense Connective Tissue Collagen fibers are not stacked regularly in rows Fibers are thicker and arranged erratically Found wherever tension might be exerted in lots of different directions such as the leathery dermis under the ksin 37 38 IRREGULAR DENSE CONNECTIVE TISSUE 39 40 DENSE CONNECTIVE TISSUE PROPER Elastic Connective Tissue Collagen with interwoven elastic fibers. Found in places in the body that requires more elasticity and rigidity such as around the joints Connecting the vertebrae so the spine can curve and twist Component of arteries – to provide support and flexibility 41 42 7  1/4/25 43 44 45 8