connective tissue Flashcards
CT is I found in every organs except
Nervous system
Distinguishable in routine HistoLogic preparations
Collagen
Collect into bundles and appear in H&E
Collagen
They appear as they are acidophilic
How can the collagen be categorized according to the structures formed by their interacting a-chains subunits
➔ Fibrillar collagen - Types I, II, III, V, and XI
➔ Sheet-forming collagen - Types IV and X
➔ Linking or anchoring collagen - Type VII, IX, XII, XIV
Basic dye that stains acidic structure
Hematoxylin in collagen
Acidic structures - nucleus and ribosome
Blue to purple
Acidic dye that stains basic structures
Eosin in collagen
Basic structures - cytoplasm and collagen
Pink
What are the three color stains that have different connective tissue
components in Masson trichome stain
Acid Fuchsin - stains the cytoplasm of the muscle, usually colors red.
Aniline blue/Light green - stains the collagen fibers that usually colors blue or green.
Hematoxylin - stains the nuclei that colors blue to black
With polypeptide subunits that aggregate to form large fibrils clearly visible in the electron or light microscope.
Fibrillation collagen
Sheet produced by epithelial cells and Specialized group of collagen that forms a mesh-like structure, a cushion roll in structural proteins and functional integrity of external laminae and basal lamina.
Sheet-forming collagen
*forms Mesh-like structure by connecting triple helixes tgt which provides cushion and structural support
Short collagens that link fibrillar collagens to one another and to other components of the extracellular membrane. Short collagens that link fibrillar collagens to one another and
to other components of the extracellular membrane.
Linking or anchoring collagen
Most abundant and widely distributed. Forms large eosinophilic bundles usually called collagen fibers. Tough, thick and fibrous protein that does not branch. Responsible to give strong fibrils
Type 1 collagen - fibrillation collagen
Size: 0.64um
Location of
Type l -
Type ll -
Type lll -
Type IV -
Type l - tendons, organ capsules and dermis
Type ll - cartilage
Type lll - reticular fibers (skin, blood vessels and lymphatic organs)
Type IV - associates with type 1, placenta and hair
Function of type IV collagen
Provide mechanical strength
Act as Adele give filter in the basement membrane
- major protein in external and basal lamina
Binds to type IV collagen and anchors the basal lamina to the underlying reticular lamina in the basement membrane
Type VII from the anchoring collagen
Function: provide mechanical strength and the skin and mucus membrane by connecting epithelial layers that underlie the stomach
Functions:
Type IX:
Type XII:
Type XIV:
Type IX:
Supports cartilage by binding type II collagen to ECM
Type XII:
Provides strength and stability in tissues - subjected to mechanical stress
Type XIV:
Ensure proper alignment and spacing of the collagen fibrils
With rubber like properties that allow tissue to be stretched or distended and return to their original shape (recoil)
Elastic cartilage
Stretched to (1.5x)
- not very strong but very flexible and stretchy
Resident cells vs visiting cells vs macrophages and mononuclear phagocyte system
Resident cells - permanently in CT
➔ Mesenchymal cells
➔ Fibroblast
➔ Fibrocytes
➔ Reticular cells
➔ Adipose cells
➔ Mast cells
➔ Macrophage
Visiting cells - mobile cells
➔ Inflammatory
➔ Macrophages
➔ Plasma cells
➔ Leukocytes
Macrophage and mononuclear phagocyte system
➔ Macrophage
➔ Mast cells
➔ Leukocytes
➔ Plasma cells
Difference between mesenchymal cells and embryonic mesenchyme
mesenchymal cells are found within the embryonic mesenchyme, but mesenchyme refers to the whole tissue, while mesenchymal cells are the specific cells inside it.
Stem cells of most CT that plays the role in maintaining homesickness
Mesenchymal cells
- homeostasis
- bound to embryo and umbilical cord
Most abundant cells or characteristics cells in CT proper
Fibroblast
*Typically have large actin nuclei and cytoplasm that goes in both directions
What does the fibroblast secretes
Organic components of the ground substances and precursor of collagen and elastic fibers
*produce and maintain ECM of most tissues
[Fibroblasts don’t make fully formed fibers right away. Instead, they first create precursor proteins (like procollagen for collagen and tropoelastin for elastic fibers). These precursors are then processed and assembled outside the cell to form the final, strong fibers.
Basically, fibroblasts lay the foundation for these fibers, and the body finishes the construction outside the cell.]
Usually spindle shaped with fewer processes
Fibrocyte
- less RER (less active)
- idle or resting stage (can turn back into fibroblast if needed
- function: maintain existing ecm and tissue structure
- darker more heterochromatic nucleus
Function of adipocyte
Cushion and insulate skin and other organs
- size 50 to 150 um in diameter
What is the characteristic feature of adipocyte
Large fat vacuole that compresses the nucleus in the periphery = signet ring appearance
Macrophage in CT
Histiocytes
- derived from bone marrow precursors, monocytes
- size is 10 to 30um in diameter
Describe structure of the
1. Macrophage
2. Mast cells
3. Plasma cells
- Macrophage
Eccentrically located, oval or kidney shaped nucleus
Nucleus is generally spherical but eccentrically placed - Mast cells
Granulated immune cells, oval shaped or irregular shaped CT - Plasma cells
Large ovoid cells with basophilic cytoplasm. Round nuclei
Counterparts of basophils which are found in blood
Mast cells (dark purple color)
- promotes allergic reactions known as hypersensitivity reactions
- function: detect invasion by microorganism
What chemical mediators of inflammation does mast cells contains
Heparin
Histamine
Proteases
Rich in RER and a large Golgi apparatus near the nucleus
Plasma cells
Leave blood by migrating between endothelial cells lining venues to enter CT
Diapedsis
(In leukocytes)
Forms a layer beneath the epithelial lining of many organs and filling the spaces between fibers of muscle and nerve
Areolar tissue
- supports many structure which are normally under some pressure and low friction
- composition:
Cells
fibers
Gel like the ECM
It plays a critical role in metabolism, endocrine function and overall body of homeostasis
Adipose tissue
- provides insulation and protection to organs
Difference between white and brown adipose tissue
Index card
Collagen fibers aligned with the linear orientation of fibroblasts in response to prolonged stresses exerted the same direction.
Dense regular ct
- offer great resistance to traction forces
Collagen fibers form a 3-dimensional network, providing resistance to stress from all directions.
Dense irregular ct
Avascular, no blood vessels. Like a gel-like material that plays a role in structures and functions of joints.
Cartilage
- durable form to support ct
- consists of cells called chondrocytes
Hyaline cartilage in adults and in embryo
Adults:
Smooth, low friction surfaces in joints
Structural support for respiratory tract
Embryo:
Temporary skeleton that is gradually replaced by bone
Cavity in the matrix holding the chondrocyte
Lacuna
- Latin word: lake or pool
- a group of lacuna: isogenous groups
Combinations of hyaline cartilage in small amounts of dense connective tissue
Fibrocartilage
Complex of concentric lamellae surrounding small central canal that contains blood vessels, nerves, loose connective tissue and endosteum.
Osteon
Aka Haversian system
What do u call a spongy bone when it is found in flat bones
Dipole
Most atypical connective tissue because it does not connect things or give support.
Blood
Why does the blood classified as CT
As it develops from mesenchyme and consists of blood cells, surrounded by a nonliving fluid matrix called blood plasma
