Connective Tissue Flashcards
what is the function of connective tissue
-provides structural support and metabolic support
- carries blood vessels
-tissue repair
-mediates exchange of nutrients and metabolites between tissue and circulation
what is primitive connective tissue derived from
mesodermal mesenchyme
describe the appearance of connective tissue
contains spindle shaped cells, jelly like ECM and some fibers
what are the cells in connective tissue
fibroblasts, reticular cells, and adipocytes
what do fibroblasts look like
pointed, elongated spindle shaped cells
what is the function of fibroblasts
synthesize and maintain proteinaceous ground substance and connective tissue fibers
what are myofibroblasts
fibroblasts with contractile ability
what are reticular cells
a type of fibroblast of lymph nodes and bone marrow
what do reticular cells look like
branched fibroblasts
what is the function of reticular cells
synthesize reticular fibers, phagocytosis
what do adipocytes look like
large, balloon shaped, clear spaces filled with lipid with a dark rim and a nucleus pushed to the outside
what do adipocytes do
storage and metabolism of lipids
what is another word for extracellular matrix
ground substance
what are the fiber types embedded in the matrix
collagen, reticulin, elastin
what does collagen do
provides tensile strength
what is the most common form of collagen
type 1
what does type 1 collagen make up in the body
loose and dense connective tissue of skin, tendons, ligaments, bone and fibrocartilage
what are the two types of type 2 collagen
hyaline and elastic
what makes up type 3 collagen
reticulin fibers, thin branching net like fibers
what does type 3 collagen do
structural support in organs
what produces type 3 collagen
reticular cells in lymph nodes, bone marrow, and fibroblasts
describe the stain of type 3 collagen
argyrophilic
where is type 4 collagen found
basement membranes
what type of collagen does ehlers-danlos syndrome affect and what are the symptoms
affects type 5 collage and it is characterized by hyperextension of joints, skin fragility, and poor wound healing
describe collagen synthesis
-initially synthesized as procollagen, composed of three alpha polypeptide chains
- packed into secretory vesicles and secreted into ECS
- modified in ECM to form tropocollagen monomers
- polymerization of tropocollagen into larger bundles results in collagen microfibrils
-microfibrils combine to form larger collagen fibers, several fibers make up a bundle
describe elastic fibers
highly branched
- random coiling pattern allows stretching
- arranged in fibers and sheets
-refractile
what synthesizes elastic fibers
fibroblasts that make a tropoelastin precursor. then polymerizes in ECM to form elastin
what are the 2 components of elastic fibers
elastin and fibrillin
describe elastin
protein core similar to collagen, surrounded by microfibrils of fibrillin
what is marfans syndrome
autosomal dominant condition resulting in abnormal elastic fibers
what happens to the body in marfans syndrome
- tall stature, long limbs and long thin fingers
- enlarged aorta with increased regurgitation and increased risk of developing a dissecting aneurysm
what makes up structural glycoproteins
fibrillin and fibronectin
where is fibronectin found and what does it do
basement membrane, aids in adhesion between cell membrane and ECM via integrins
what are integrins
adhesion molecules
what are some non- filamentous molecules that make up basement membranes
laminin, entactin, tenascin
what is ground substance
amorphous, transparent material with properties of a semi fluid gel
describe the chemical structure of what makes up ground substance
long, unbranched polysaccharide chains of repeating disaccharide units
- one of the two sugars is always an amino sugar (GAG)
what are proteoglycans
most GAG molecules bind to protein molecules to form these
what happens with non-functional or insufficient lysosomal enzymes
lysosomal storage diseases “mucopolysaccharidoses”
what is ground substance mostly made of
GAGs, proteoglycans and water
whats the most common GAG in loose connective tissue
hyaluronic acid
describe the polarity of GAGs
negatively charged due to sulfate and carboxyl side groups, hydrophilic which gives rise to gel like property
what are the forms of connective tissue
loose (areolar) connective tissue and dense connective tissue
describe the appearance of loose connective tissue
sparse fibers, abundant ground substance, viscous gel like consistency
what is the function and location of loose CT
function: support
location: beneath epithelia and around nerves and vessels
what is the function of dense connective tissue and describe the appearance
provides structural support, abundant fibers, moderate number of cells, less ground substance
what are the 2 types of dense CT
regular and irregular
describe regular dense CT
collagen fibers oriented parallel to each other, densely packed fibers and cells arranged in fascicles
describe irregular dense CT
collagen fibers oriented randomly, moderate number of fibers and few cells
what does specialized CT make up
bone, blood, cartilage, adipose tissue, hematopoietic tissue and lymphatic tissue,
- mesenchymal and mucus CT in embryo
what are adipocytes derived from
lipoblasts
what is the function of adipose tissue
energy storage, thermoregulation and shock absorber
what are the types of adipose tissue
white fat and brown fat
where is white fat located
distributed in dermic and around intraperitoneal organs
what is another term for white fat
unilocular
what is another term for brown fat
multilocular
what is the function of brown fat
thermoregualtion
where is brown fat located in humans
adrenals
what makes brown fat brown
the large amount of mitochondria
what gives brown fat the capability to thermoregulate
the large amount of mitochondria create large amount of energy for heat production
