Connective Tissue I & II

Question 1

Basic Functions of Connective Tissues

Answer 1

1. Structural framework of the body
2. Conducts and translates muscle contractions into movement
3. Forms stoma of glands and organs
4. Medium for metabolic exchange
5. Site of fat and mineral storage

Question 2

General Characteristics of CT

Answer 2

-Low cell density, extensive extracellular matrix
-Tends to be highly vascular (except cartilage)
-Most retain stem / mitotic cells

Question 3

CT Extracellular matrix composed of:

Answer 3

1. Ground Substance
2. Fibers

Question 4

Ground substance

Answer 4

Colorless, transparent, gel-like
Highly hydrated
Mix of macromolecules (proteoglycans, glycosaminoglycans)

Function:
1. Cushion against compression
2. Aid in material exchange

Question 5

Glycosaminoglycans (GAGs)

Answer 5

• Repeating disaccharide units
• Neg charged, attracts Na+
• Hydrating element of ground substance

Question 6

Proteoglycans (PGs)

Answer 6

GAGs covalently bonded to core protein

Proteoglycan aggregates: extremely large aggregate of PGs
- enhance the role of GAGs in the tissue - “biological sponge”
- occupies large volume; resists fluid movement

Question 7

Fibers in ECM

Answer 7

Collagen and Elastic

-Determines physical properties
-Varies greatly with tissue
-Synthesized and secreted by cells

Question 8

Collagen

Answer 8

Most common protein in the body
-Fibrous proteins present in large quantities in CT
-Imparts tensile strength (flexible, but no elastic)
-Often self-assemble into higher-order structures (fibrils, fibers, bundles)

Question 9

Type I Collagen

Answer 9

Most common type
-Highest tensile strength
-Gross view: white
-LM: pink (acidophilic) fibers and bundles with H&E

Makes up: bone, teeth, ligaments/joint capsules, tendons, dermis of the skin, fibrocartilage

Question 10

Type II Collagen

Answer 10

Slender fibrils found in cartilage

Question 11

Type III collagen

Answer 11

AKA reticular fibers
-Functions to filter fluid
-Appears delicate, branching, dark-staining with silver

Question 12

Elastic Fibers

Answer 12

-Imparts Elasticity
-If present, usually accompanies collagen
-core of elastin surrounded by sheath of microfibrils

-darker and thinner than collage on LM
-don’t branch like reticular fibers

Question 13

CT cells

Answer 13

Some cells originate and reside in CTs

Most cells develop elsewhere

Question 14

Fibroblasts

Answer 14

-Most abundant and widely distributed of fixed cells
-Capable of producing all ECM components
-Especially active during growth, wound healing, scar tissue formation
-LM: elongated, oval nucleus