Intro to CT Flashcards
What are the functions of CT?
Provide and maintain form in the body
Provide a matrix that connects and binds cells and tissues together
Serve as a reservoir for hormones that control cell growth and differentation
Medium through which nutrients and metabolic wastes are exchanged b/w cells and their BS
What are the three main components of CT?
1) Cells-many types
2) Fibers-protein polymers—collagen fibers, also reticular and elastic
3) Ground substances-viscous mixture of water, proteoglycans, glycosaminoglycans, and glycoproteins=ECM
Mesenchymal Cells
fibroblasts, chondrocytes, osteoblasts, adipocytes, endothelial cells, and smooth muscle cells
Hematopoietic Cells (blood)
mast cells, basophils, eosinophils, neutrophils, macrophages, lymphocytes (T & B cells), RBCs
Macrophage-like cells
monocytes (blood), macrophage (tissue), multinuclear giant cell (CT), kupffer cell (liver), microglia (CNS), Langerhans cells (skin), dendritic cell (lymph nodes), osteoclasts (bone)
I.E. cells that remove debris and “bad guys”
What are the fibers that CT can be?
collagen, reticular, and elastic fibers
–amount and type present in a tissue give characteristics to each particular CT
Important CTs include:
Tendons, ligaments, aponeuroses, fascias, dermis, organ capsules, stroma of organs, covering of muscles and nerves, membranes (meninges) surrounding the CNS
Collagen Fibers
provides resistance to tensile force: prevent tissues from being pulled apart from each other
There are 25 “collagen types” however 1,2,3,4 are the most abundant
1>3>2>4
Each fiber is made of bundled collagen fibrils
Type 1 Collagen
strongest, largest collagen fibers, most abundant type
Type 2 Collagen
found in articular cartilage and fibrocartilage
Type 3 Collagen
synonymous with reticular fibers; found in skin, artery wall, scar tissue, loose CTs
Type 4 Collagen
major filament of basement membranes (basal lamina)
Reticular fibers
composed of type 3 collagen fibrils
smaller diameter and “loosely” arranged
- -creates a flexible network for organs that incur volume changes (arteries, spleen, liver, uterus)
- -abundant in smooth muscle, neurons (endoneurium), and hematopoietic organs (bone marrow, lymph nodes, spleen papillary layer of dermis–sits directly under the basement layer)
Elastic fibers three types
oxytalan, elaunin, elastin
Oxytalan
small fibers that do not actually contain elastin protein but are resistant to tensile forces
Elaunin
mixture of elastin protein and oxytalan fibers
Elastin
polymers of elastin aggregate in the center of elastic fibers and are surrounded by network of oxytalan and elaunin fibers
Ground substance (tissue fluid)
viscous, hydrophilic substance with many macromolecules; occurs BETWEEN cells
Macromolecules
(glycosaminoglycans(GAG), proteoglycans, glycoproteins)
bind cell surface receptors to fiber components of ECM
anchor cells w/in ECM; provides tissue strength and rigidity
What does ECM=
fibers + ground substance
Glycosaminoglycans
Hyaluronic acid = articular cartilage
Chondroitin 4-sulfate = cartilage, bone, skin
Chondroitin 6-sulfate = cartilage, skin, aorta
Dermatan sulfate = skin, tendons
Heparan sulfate = lung, liver, basement membrane
Keratan sulfate = cartilage, nucleus pulposus, annulus fibrosus
What is CT proper?
Loose CT Dense CT (regular or irregular): tendons, ligaments, fascia, some CT of organs
Specialized Connective Tissue
adipose, elastic, hematopoietic, and mucous tissue (umbilical cord)
Supporting CT
cartilage and bone
What does loose CT support?
structures that are normally under low pressure and low friction forces
Characteristics of Loose CT
flexible tissue, well vascularized, not very resistant to tensile stress
contain mainly fibroblasts and collagen, w/lesser amounts of elastic and reticular fibers
VERY COMMON
Where do you find Loose CT
Epithelium, endomysium, endoneurium, dermis, lining of peritoneal and pleural cavities, surrounding glands, blood vessels and mucous membranes
What is dense CT main fxn?
offer resistance to tensile force and protection of tissues
Characteristics of Dense CT
fewer cells (fibroblasts) and predominance of collagen fibers compared to loose CT Minimally flexible and highly resistant to stress (especially tension) composed of irregular and regular types dependent on arrangement of fibers in ECM
Dense regular CT
collagen bundles arranged into a definitive, linear pattern designed to with stand prolonged stresses exerted in the direction of fiber alignment
Examples: Tendons, ligaments
Dense irregular CT
Collagen fibers are arranged in bundles w/o a definite orientation
provide resistance to stress in all directions
Example: Dermis (reticular layer)
Elastic tissue: yellow
ligamentum flavum is most common site of this
composed of thick, parallel elastic fiber bundles and fibroblasts
thin collagen fibers are scattered among the elastic fiber bundles
provides elasticity to tissues; provides recoil from flexed positions
Reticular Tissue
loose CT: specialized
Reticular fibers and cells form a sponge-like structure where cells and fluids can move easily
