connective tissues proper

Question 1

Important characteristics

Answer 1

• Relatively few cells
• Large amount of nonliving substance (extracellular matrix):
• Ground substance
• Fibers
• Vascularized (except cartilage & blood)

Question 2

Functions

Answer 2

• Support & protection
• Defense
• Transport & exchange
• Insulation & energy storage (fat)

Question 3

Cell structure

Answer 3

• Derived from mesenchyme (detached cells in embryo)
• A characteristic type of cell for each kind of CT - Cells secrete extracellular matrix
• May also have other cells (e.g. defense cells)

Question 4

Cell matrix structure (Fibers)

Answer 4

collegen, reticular and elastic

Question 5

Collagen fibril

Answer 5

group of collagen

molecules bound together

Question 5

Collagen fiber

Answer 5

group of collagen fibrils bound together
- Properties:
• Resists tension (pulling)
Like “steel cable”

Question 6

Reticular fibers structure

Answer 6

•  Each reticular fiber is made of
specialized collagen fibrils
- Made of Type III collagen molecules
•  Fibers are short, thin, branched 
  What does “reticular” mean? Network. 


Question 7

Resticular fibers properties

Answer 7

Forms delicate networks with lots of spaces • Allows smooth gliding / deformation
- Used at boundaries of tissue (e.g. surrounds capillaries)
Like a “folding trellis”

Question 8

Elastic fibers Structure

Answer 8

• Main protein is elastin
- Coils up at rest
Like a “spring”
- Elastin molecules cross-linked in large groups to form a fiber (no fibrils)

Question 9

Elastic fibers properties

Answer 9

• Highly elastic: i.e.recoilsto original shape

Question 10

Genetic diseases of CT fibers

Answer 10

•  Cutis laxa
- Genetic defect in
elastic fiber formation
- Loss of elasticity in skin, joints
•  Ehlers-Danlos syndrome - Genetic defect in
collagen fiber formation
- Highly flexible skin, joints
Both these diseases increase cardiovascular risks

Question 11

Matrix ground substances

Answer 11

• Glycosaminoglycans (GAGs)
• Proteoglycans
• Interstitial fluid (tissue fluid)
• Additional components (e.g. calcium salts in bone)

Question 12

Four classes of connective tissue

Answer 12

• Connective tissue proper
• Cartilage
• Bone tissue
• Blood

Question 13

Connective tissue proper

Answer 13

• Relatively unspecialized – “classic” CT • Cells: Fibroblasts(secretematrix)-also
other cells

Question 14

six types of connective tissue proper

Answer 14

varying in density & types of fibers: -
- Loose connective tissue ( areolar, adipose, reticular)
• Lots of ground substance, fewer fibers
- Dense connective tissue (regular, irregular, elastic)
• Lots of collagen fibers

Question 15

Loose connective tissues

Answer 15

Aerolar, Adipose and reticular

Question 16

Aerolar tissue

Answer 16

most widespread, “generic” CT -

• Gel-like matrix, lots of tissue fluid ( common to all CT)
• Adjoins all epithelia
• All 3 fiber types
• Has defense cells to fight infections
• Has fat cells to store energy

Question 17

What is the role of areolar connective tissue in exchange:

Answer 17

look up in textbook

Question 18

Adipose tissue

Answer 18

• Mostly fat cells
• Inhypodermis (superficialfascia) – located where?
• Also “visceral fat” around internal organs - Energy storage, protection, insulation

Question 19

Reticular tissue

Answer 19

• The only fibers are reticular ( specialized collagen fibrils)
• Exclusively in lymphoid organs (spleen, red bone marrow, lymph nodes)
• Labyrinth used by defense cells

Question 20

Dense regular connective tissue

Answer 20

• All collagen fibers run in 1 direction (axis) - Resists tension in 1 direction (axis)
• Tendons and ligaments
• Fascia (deep fascia)

Question 21

Dense irregular connective tissue

Answer 21

Like areolar CT, but many more collagen fibers - Collagen fibers oriented in different directions

• Resists tension in different directions
• In dermis, and fibrous capsules of organs/joints

Question 22

Elastic dense CT

Answer 22

• Most fibers are elastic fibers (also collagen fibers)
• Able to recoil after stretching
• Bronchial tubes in lungs; artery walls; some intervertebral ligaments