Connective Tissues Flashcards
What are the components of connective tissues?
Ground substance
Extracellular fibers
Cellular elements
What is the ground substance?
Matrix that allows diffusion and binds fibers and other elements together
What is the ground substance composed of?
Glycosaminoglycans (GAGs)
Water
Calcium in bone
What are the purpose of extracellular fibers in CT?
To provide strength and flexibility
-they will either be collagen or elastin
What is the purpose of the cellular elements in ct?
To secrete fibers and ground substance
Name the sulfate glycosaminoglycans (GAGs)
Heparan sulfate
Dermatan sulfate
Keratin sulfate
Chondroitin sulfate
Name the non-sulfate GAGs
Hyaluronic acid
What are glycosaminoglycans GAGs?
Polysaccharides made from disaccharide subunits
What is a proteoglycan?
Polysaccharide attached to a protein
What synthesis ground substance?
Fibroblast
Osteoblasts
Chondroblass
Adipocytes
What is the function of the ground substance?
- negatively charged to maximize volume/ trap water/ bind to collagen for strength
- matrix for cells and blood vessels and a diffusion medium for nutrients
- enable tissues to withstand compression
Which collagen is the only one that stains with H and E?
Type I
Which collagen form distinctive banded fibrils in electron micrograph?
1,2,3,5,11
What is collagen?
A major fiber component of CT with great tensile strength
What secrete collagen?
Fibroblasts, osteoblasts, chondroblasts, adipocytes
-same as ground substance
What are some characteristics of type I collagen?
Stains with H and E (unique)
Forms large fibers
In loose and dense irregular ct, tendons, ligaments, bone and fat
-made by fibroblasts, osteoblasts and adipocytes
What are some characteristics of type 2 collagen?
Only found in cartilage
Made by chondroblasts
What collagen forms reticular fibers?
Type 3 collagen
What does type 3 collagen do?
Forms a supporting framework for bone marrow, lymph glands, spleen and thymus
(Component of basement membranes)
What makes type 3 collagen?
Fibroblasts
Minor collagen types
Place holder
Collagen in basal lamina
Place holder
Where is elastin found?
Loose and dense irregular CT (esp. skin), elastic cartilage and some ligaments
What secretes elastin?
Fibroblasts secret as proelastin which then assemble on secreted fibrillin fibrils
Where is elastin secreted without fibrillin to form elastic sheets instead of fibers?
Smooth muscle cells in the arteries
What are the characteristics of loose irregular (areolar) CT?
Abundant ground substance with few fibers and variable cell numbers
- contain many capillaries
- contains many immune cells to fight bacteria
What facilitates waste and nutrient exhange with capillaries in loose irregular CT?
Diffusion in ground substance
What forms the fluid in the ground substance?
Formed by transcytosis of fluid through capillary endothelial cells
Where are CT cells derived from? (What is the embryonic cell)
Mesenchyme
What is mesenchyme?
The stem cell of many tissues in the body
??? Look at slide
What kind of cells can mesenchyme make?
Fat
- loose and dense CT
- blood vessels and organs (smooth)
- blood vessel lining (endothelium)
- mesothelium
- cartilage
- bone
What are active cells usually called?(fibro)
…..blasts
These cells have oval nucle and are motile
What are inactive cells called?(fibro)
Cytes
They have spindle-shaped basophils nuclei and are attached to collagen 1 fibers
What do fibroblast/cyte do?
Produce and maintain collagen, elastin, glycosaminoglycans
Where are the cells derive from hematopoietic stem cells found?
In loose or dense irregular ct
These are cells of the immune system and are involved in inflammation
What cells are derived from hematopoietic stem cells?
Eosinophils Neutrophils B no T lymphocytes Plasma cells Macrophages Mast cells
Osteoclasts in bone
Describe White “unilocular” fat
Large cells
Function to store and release energy
Fat is stored as a single triglyceride droplet free in the cytoplasm
can increase during periods of estrogen hormonal change (puberty) or high fat intake
What do chylomicrons do?
Absorb small lips droplets from ingested lipids (after being broken down).
Where does lipid absorption occur in intestine?
Lipid absorption in enterocyte of intestine epithelium
What promotes the storage of fat?
Estrogen- increases ft storage (difference in sex)
Insulin- promotes fat storage and uptake of glucose
What controls the release of fat from storage?
Epinephrine (adrenalin) - promotes fat release (as fatty acids and glycerol)
Norepinephrine (noradrenalin)- promotes fat release
What is hypertrophic obesity?
Due to enlargement of adipocytes
What is hyperplastic obesity?
Due to increase in adipocytes numbers (hyperplasia)
What are the attributes of brown fat?(Multilocular)
Themogenesis in infants
In neck, back, and around organs to maintain temperature
Massive blood supply
Large, abundant mitochondria
Color comes from blood in capillaries as well as mitochondrial cytochromes
Highest metabolic capacity in the body
Reverts to unilocular precursor cell before 10 years of age
