Ex 1: Connective Tissue

Question 1

Subdivisions of adult connective tissue

Answer 1

• elastic
• reticular
• loose
• dense

Question 2

Subdivisions of special connective tissue

Answer 2

• adipose
• cartilage
• bone
• hematopoietic

Question 3

Loose adult connective tissue

Answer 3

both collagen and elastic fibers are present and arranged in a very loose, random fashion

Question 4

Dense adult connective tissue

Answer 4

collagen fibers predominate

Question 5

Reticular adult connective tissue

Answer 5

reticular fibers predominate

Question 6

Elastic adult connective tissue

Answer 6

elastic fibers predominate

Question 7

Embryonic connective tissue

Answer 7

• found in umbilical cord and in the pulp of developing teeth
• referred to as Wharton’s jelly in umbilical cord
• composed of some collagen and elastic fibers but mostly an abundance of extracellular matrix

Question 8

Loose adult CT

Answer 8

• areolar
• high ratio of fibroblasts to fibrous components
• type I collagen and elastic fibers
• found beneath epithelial tissues of most organs, including the tunica adventitia of blood vessels
• contains fibroblasts, mast cells, macrophages, and capillaries

Question 9

Dense regular adult CT

Answer 9

• high ratio of fibrous components of fibroblasts
• thicker bundles of collagen than in loose CT
• characterized by highly ordered bundles of collagen separated by single rows of fibroblasts
• found in tendons an dligaments

Question 10

Dense irregular adult CT

Answer 10

• high ratio of fibrous components to fibroblasts
• thicker bundles of collagen than in loose CT
• no specific orientation of collagen bundles
• found in fascia, submucosa of GI tract, and in dermis of integument

Question 11

Reticular adult CT

Answer 11

• type of dense irregular connective tissue with a predominance of reticular fibers
• associated primarily with lymphatic tissue

Question 12

Elastic adult CT

Answer 12

• dense irregular CT with abundance of elastic fibers which form discontinuous lamellae
• associated with walls of blood vessels produced by smooth muscle cells not fibroblasts

Question 13

Special CT classes

Answer 13

• adipose
• cartilage
• bone
• hematopoietic

Question 14

Adipocytes

Answer 14

• derived from undifferentiated mesenchymal cells and distnguished by their unique appearance
• types: white fat and brown fat

Question 15

White fat

Answer 15

• adipocytes
• distributed throughout body
• unilocular

Question 16

Three subdivisions of connective tissue

Answer 16

Embryonic
Adult
Special

Question 17

Connective tissue matrix

Answer 17

• most common cells are fibrocytes and fibroblasts scattered in homogeneous mixture
• matrix contains protein fibers and ground substance

Question 18

Types of protein fibers found in connective tissue matrix

Answer 18

• collagen
• reticular
• elastic
• ground substance: glycosaminoglycans and glycoproteins

Question 19

Collagen fiber synthesis

Answer 19

• Type I collagen is synthesized as a prepropeptide
• the signal sequence (pre) is cleaved after translocation of polypeptide into ER lumen of the fibroblast
• propeptide (procollgen) is secreted by fibroblast into extracellular matrix. Pro collagen has non-helical ends that prevent polymerization
• non-helical ends cleaved by peptidases then molecule is referred to as tropocollagen
• polymerize and now it’s collagen!

Question 20

Elastic fiber synthesis

Answer 20

• synthesized as prepropeptide
• secreted as propeptide
• converted to tropoelastin by extracellular enzymes that are also secreted by fibroblast
• tropoelastin monomers assemble into amorphous fibers or sheets with the aid of several types of fibrillin

Question 21

Glycosaminoglycans (GAGs)

Answer 21

• large, negatively charged linear polysaccharides
• form most of amorphous substance of connective tissue with glycoproteins
• all except for hyaluronic acid are covalently linked to protein to form proteoglycans
• four groups: hyaluronic acid, heparin and heparan sulfate, chondroitin, keratan

Question 22

Four groups of GAGs

Answer 22

• hyaluronic acid
• heparin and heperan sulfate
• chondroitin sulfate and dreamt sulfate
• keratan sulfate

Question 23

Hyaluronic acid

Answer 23

• largest of the GAGs
• cartilage, skin, synovial fluid, general CT
• only GAG that lacks sulfate group
• consists of repeating carb chains of N-acetylgucosamine and D-glucoronic acid
• present in nearly all connective tissues and in vitreous body of the eye, synovial fluid, and Wharton’s jelly
• binds readily with water and serves as a lubricant in synovial fluids