HE8 & 9 Connective tissues Flashcards
Important functions of CT?
Structure (bones, cartilage, ligaments), Movement (ligaments). Support glands/organs. Store fat.
- Attracts water
- Exchanges blood/lymph, fluid.
- initial site of response to injury/host defense
Composition of CONNECTIVE TISSUES?
Cells separated throughout an Extracellular matrix ECM.
Composition of GROUND SUBSTANCE?
- Glycosaminoglycans (GAGS)
- Proteoglycans (PG’s)- > protein core w/ GAG’s
- Multiadhesive glycoproteins (MGP’s)
Composition of GAG’s
- repeating units of DISACCHARIDES (not mono or tri)!
- NEGATIVELY CHARGED
and most are SULFATED (hyaluronin not sulfated)
Primary function of glycosaminoglycans and proteoglycans? Function in BM?
important for movement of cells/materials & est. concentration gradient.
Basement membrane= CHARGED BASED FILTRATION BARRIER
Proteoglycan agregates structure and function
Glycosaminoglycans bound to a core protein forms a hydration unit of PROTEOGLYCAN.
Proteoglycans are linked by “linker proteins” to HALURONIN protein core
Gives ECM gel-like state, resisting compression to act like “SHOCK ABSORBERS”
GAG’s, PG’s, PG agregates at LM
GAG’s/PG’s high negative charge stain w/ basophilic BLUE basic dyes
HE STAIN= BLUE/PURPLE
PAS= MAGENTA/PINK
Multiadhesive glycoprotein (MGP) 5 Structures/ 4 functions.
Remember picture of MGP’s parallel under plasma membrane bound to green INTEGRINS which go through plasma membrane and attached to actin.
- Fibronectin
- Laminin
- Tenascin
- Osteopontin
- Enactin/Nidogen
- ECM assembly/structure
- Adhesion (fibroblast to ECM)
- Mechanosensation (FOCAL ADHESION)
- Regulate cell migration
Fibronectin, Laminin, or Osteopontin are examples of what?
Multiadhesive glycoproteins
Elastic fiber distribution. STAIN? Structure?
- Dermis-skin
- Heart valves
- Walls of large arteries (AORTA)
- Lungs (alveolar walls)
Ocrein used to distinguish between collagen and elastic fibers.
ELASTIN core with FIBRIN microfibrils
What 4 cells make COLLAGEN?
Where does Fibril formation occur?
What 3 categories? and what type Collagen in each category?
- Fibroblasts
- Epithelial cells
- Smooth muscle cells
- Schwann cells (PNS)
MADE OUTSIDE THE CELL!
- Tropocollagen–>Fibril
- Fibrillar (I,II,III)
- Network forming (IV)
- Anchoring (VII)
AT TEM what periodicity seen in Collagen?
68nm
68nm periodicity relates to what kind of cell?
Collagen FIBRILS (type 1,2,3). as a result of the orderly staggered assembly of tropocollagen into fibrils (overlap and holes).
Which type of molecule forms Fibrils, Fibers, and Bundles? Where found?
WHAT STAIN>
TYPE 1 COLLAGEN.
- sclera
- dentin
- orgain/joint capsules
- scar tissue
(Dermis, hypodermis, fascia, bones, ligaments, joints, tendons)
HE=pink bundles
TRICHROME-blue green
_______ found in cartilage and vitreous humor and stain______ whith _______stain. What happens if there is alot of PG’s present with it?
Type 2 Collagen
(restrains PG aggregates from expanding)
stains light pink with HE stain. if high PG’s blue masks over light pink type 2 collagen
LM looks like smooth fiberglass finish (blue, light pink) with large eye looking bubbles. TEM looks like unfinished rough fiberglass like on back side of a tub/shower
Type 2 collagen fibrils
____is first type of collagen in embryo and during adult injury repair and is replaced with ______. When heavily _____ the fibers are referred to as _______. They are often stained ______ with _____.
TYPE 3 COLLAGEN, TYPE 1 COLLAGEN, GLYCOSYLATED, RETICULAR FIBERS, BLACK, SILVER STAIN.
What type of collagen fibers form a delicate lattice that supports organs that :
- filter blood/lymph (liver,spleen,lymph),
- rich vasculature (endocrine organs),
- proliferating cells (bone marrow)
Reticular fibers of Type 3 collagen.
REINFORCE/SUPPORT SMALL BLOOD VESSEL WALLS
found supporting: Adipocytes Smooth muscle fibers peripheral nerve fibers -walls of blood/lymph vessels
What connective tissue supports/anchors epithelium to BL and is part of the filtration barrier?
Structure? Location? Function?
TYPE IV COLLAGEN- Basal Lamina- FILTRATION
- no fibrils or periodicity
- flat sheets of type IV MONOMERS
Attaches Epithelium to BL
What connective tissue anchors BL to RL?
Type VII Collagen- Anchoring FIBRILS
RL ADHESION!
Problems in what type of collagen cause HEMATURIA, BLISTERS, BRUISING, TENDON RUPTURE, OCULAR SHAPE CHANGE?
Type IV— BL FILTRATION- blood in urine
Type VII—RL ADHESION- blisters
Type III—- Supports small blood vessels- bruising
Type I—— bundles DiRCT- tendon injury
Type II—– Restrains PG’s in vitreous - eye deformities
PRIMARY FIBER DEFECTS & PATHOLOGY:
Type 1,2,3,4,7
I. Osteogenesis imperfecta II. Achondrogenesis II III. Ehlers-Danlos IV IV. Alport's syndrome VII. Kindler's Syndrome
Alport's syndrome- Kindlers syndrome- Ehlers-Danlos IV Achondrogenesis II Osteogenesis imperfecta
I. Osteogenesis imperfecta II. Achondrogenesis II III. Ehlers-Danlos IV IV. Alport's syndrome VII. Kindler's Syndrome
Where is CT derived from ? Where is that derived from?
Mesenchymal cells– from mesoderm and Neural Crest
Adults have mesenchymal-like cells in CT
What is the name for a neoplastic mesenchymal cell of adipocyte that becomes malignant? for a benign fibroblast?
Fibrosarcoma
lipoma
Tissue macrophages and mast cells are examples of what kind of cells in the CT.
Resident cells- long lived- mesenchymal like- renewal
What is the principal resident CT cell? LM TEM
FIBROBLASTS- makes all ECM components
LM- long flat cell, basophilic cytoplasm.
ECM- protein secreting cell- constitutive
Activated state- lined up next to each other
Quiet state- widely dispersed
MYOfibroblasts vs fibroblasts at TEM
Fibroblasts look like protein secreting cell- long flat
Myofibroblasts have bundles of actin filaments (hard to see) but looks more wild like mesenchymal star shape ec.
Myofibroblasts vs fibroblasts in wound healing.
Whats myofibroblast NOT involved with? in terms of wound healing*
Fibroblasts (24hrs)- Quick repair- makes initial ECM with TYPE III collagen (later replaced w/ type I).
Myofibroblasts (1week)- repair/active 2nd week- apoptosis, approximates tissues to bring closer together
MYOBLAST NOT INVOLVED WITH ECM REMODELING
Histocytes
Monocytes migrate from blood into CT and differentiate into MACROPHAGES (HISTOCYTES)
Macrophage (not monocyte) is considered resident Sentinel cell.
TEM LM of Macrophage
nucleus to one side, looks like has wart bubbles all over it
TEM: features of phagocytic cell (lots of storage molecules with different shapes colors and sizes.
Multinucleated giant cells (foreign body giant cells)
Macrophages fuse together to attack or wall off large foreign invaders
3 secretions of Mast Cells. other secretions?
PROMOTES INFLAMMATION
Heparin (GAG)- anticoagulant
Histamine- (increases vascular permeability, smooth muscle contraction, mucus production)
WBC chemotactic factors
Leukotrienes (sm contraction) & cytokines- PROMOTES INFLAMMATION.
Releases from granules
Where are mast cells found? what antibody receptor?
Skin, Respiratory, GI. IgE
Multilocular fat-
Brown fat- for thermal heat generation
Transient cells- derived, lifespan, function
from bone marrow (elsewhere), short lived, WBC’s Plasma cells, injury, inflammation, immunity
Where are plasma cells derived? Function?
B-lymphocytes make plasma cells for Antibody production (iG’s) immunoglobulins
LM: tear shaped eccentric nucleus, clock face/cartwheel patter, lighter in middle (negative golgi-pale center)
Plasma cell
RETICULAR LAMINA- what kind of collagen?
Reticular fibers (type III) Anchoring fibers (type VII)
Where are mesenchymal cells found?
Ground substance
