Lecture 8 - Connective Tissues I Flashcards
What are the characteristics of connective tissues?
- low cellularity
- abundant matrix
- matrix consists of various protein fibers
- classified by type of matrix, fiber density, and fiber organization
What are the functions of connective tissue?
- supports other tissues
- binds other tissues together
- structural framework
- opposes gravity
- creates body contours
- contains specialized tissues (lymph and hematopoietic)
What are the categories of connective tissues and how are they grouped?
Embryonic
-Wharton’s jelly
Adult
- elastic
- reticular
- loose
- dense
Special
- adipose
- cartilage
- bone
- hematopoietic
Describe the types and organization of fiber types in loose adult connective tissue.
Collagen and elastic fibers arranged in a loose, random fashion.
Describe the types and organization of fiber types in dense adult connective tissue.
Dense collagen fiber either arranged in parallel to one another (dense regular) or haphazardly (dense irregular).
Describe the types and organization of fiber types in reticular adult connective tissue.
Primarily reticular fibers.
Describe the types and organization of fiber types in elastic adult connective tissue.
Elastic fiber predominate.
What are the types of adipose tissue? Compare them.
White fat:
- unilocular
- found throughout the body
Brown fat:
- multilocular
- abundant mitochondria giving brown color
- found primarily infants
Describe the process of adipogenesis.
Mesenchymal stem cells differentiate into white fat preadipocytes or myoblast/brown fat preadpiocytes.
White fat preadipocytes differentiate into white fat and myoblast/brown fat preadipocytes differentiate into myoblasts or brown fat preadipocytes followed by brown fat adipocytes.
Describe the process of collagen I synthesis.
- starts as prepropeptide
- signaling “pre-“ sequence is cleaved forming propeptide (procollagen)
- procollagen is secreted into ECM
- non-helical end (prevents polymerization) is cleaved forming tropocollagen
- tropocollagen spontaneously assembles into collagen with a 64nm banding patter
What are the main component of the amorphous ground substance?
- GAGs (glycosaminoglycans)
- glycoproteins
What is hyaluronic acid?
- largest GAG
- found in nearly all connective tissue
- lacks a sulfate group
- binds water and acts as a lubricant
What is heparin/heparan sulfate?
-GAG found in basement membrane, skin, lung, liver, blood vessels, and mast granules
What are chondroitin and dermatan sulfate?
- GAG found in cartilage, bone, skin, blood vessels, heart valves, and the cornea
- most abundant
What is keratan sulfate?
- GAG
- type I found only in cornea
- type II found in cartilage and nucleus pulposa of intervertebral disks
