Hist: Connective tissue Flashcards
Characteristics of Connective tissue
not exposed to outside environment covered by epithelium
cells separated via extracellular matrix
Extracellular matrix is a gel like substance with embedded protein fibers
ECM in bone is mineralized
-carries O2, CO2, nutrients, and wastes
Embryonic CT
contain pluripotent stem cells
Adult CT types
Fibrous CT:
loose (areolar CT)
Dense regular
Dense Irregular
special CT:
adipose, catrilage, bone, hematopoietic
Functions of CT
structural faramework of the body Protection: dermis and bones Supports and interconnects other tissues Energy storage:adipose Transports Defense against microorganisms
Fibroblast cells
produce collagens, proteoglycans and glycoproteins
Mesenchymal cells
connective tissue stem cells
Chondrocytes
produce and maintain cartilage components
Osteoblasts
produce bone components
Hematopoietic stem cells
produce red blood cells and immune cells
Type 1 collagen fibers
aligned and crosslinked to increase tensile strength
fibril alignment
lack of ascorbate lead to scurvey, weakens CT
abnormal collagen synthesis is the Ehlers Danlos Syndrome
Amorphous Ground substance
Proteoglycans: chondrotin, heparan, keratin sulfates
Hyaluronan: link the proteoglycans together
Glycoproteins: cytokines
growthfactors
structural proteins
Extracellular proenzymes
Cell ECM interactions
integrins syndecans CD44 bind hyaluronan growth factor receptors cytokine receptors
Embryonic Connective tissue characteristics
Rich in ECM
rich in mesenchymal stem cells (multipotent)
not as many collagen or reticular fibers
Wartons jelly in umbrical cord
fibrous Loose connective tissue
more glycans than fibers
areolar: low density tissue with fixed and wandering cells
adipose: fat containing tissue
reticular: rich in reticular fibers, forms an open framework to create a supportive mesh work for holding free cells
Fibrous dense connective tissue
more fibers than glycans
dense irregular CT: fibers are deposited in a random patttern ie dermis of the skin
Dense regular CT: fibers are deposited in a highly regular pattern i.e. tendons of muscles
Elastic Connective tissue: rich in elastin fibers
Fixed loose areolar CT cells
fibroblasts
adipocytes
mesenchymal cells
wandering loose areolar CT cells
macrophages
mast cells
leukocytes/lymphocytes
plasma cells
loose connective tissue functions
support and bind other tissues, hold body fluids and defends against infection
found beneath membraneous epithelia and around BV, muscles, and nerves
Adipose CT functions
abundant adipocytes and sparse ECM
provides energy and insulation
supports and protects organs:
found under skin around organs and within abdomen breasts and buttocks
white fat
functions in energy storage, insulation and cushioning and hormone secretion
brown fat
key thermogenic tissue, abundant in newborns, greatly reduced in adults
Reticular Connective tissue
rich in reticular fibers
forms an open framework to create a labyrinth for holding free cells
found in liver, bone marrow, lymph nodes and spleen
meshwork houses blood cells and immune cells outside the blood and lymphatic vessels
Dense irregular Connective tissues
large bundles of collagen fibers and few nuclei of fibroblasts irregularly packed
found in dermis of skin, capsules that surround internal organs
perichondrium and periosteum
fascia
Dense regular CT
tightly bound regularly arranged collagen
fibroblasts are the principle cell type
resists pulling forces
poorly vascularized
wavy appereance not under tension
found in: tendons, ligaments, aponeuroses
dense fascia and joint capsules
