Fibrous Connective Tissue

Question 1

What are some characteristics of connective tissues? (4)

Answer 1

1. CT is never exposed to the outside environment
2. CT cells are separated by ECM
3. Contains ECM, which is embedded in protein fibers, carries O2, CO2, nutrients and waste
4. There is embryonic and aduct CT

Question 2

What are the main functions of CT? (6)

Answer 2

1. Structure
2. Protection
3. Support/interconnection
4. Energy storage (adipose tissue)
5. Transports fluids
6. Defense against microorganisms

Question 3

What do fibroblasts do?

Answer 3

produce collagens, proteoglycans and glyocproteins

Question 4

What are mesenchymal cells?

Answer 4

connect tissue stem cells (multipotent)

Question 5

What do adipocytes do?

Answer 5

Store and release fats

Question 6

What do chondrocytes/chondroblasts do?

Answer 6

produce and maintain cartilage components

Question 7

What do osteoblasts/osteocytes/clasts do?

Answer 7

Produce bone components

Question 8

What do hematogpoeitic cells do?

Answer 8

Produce red blood cells and immune cells such as macrophages and mast cells

Question 9

What are the 3 types of fibrous components in CT, and what do they do?

Answer 9

Collagens (type 1 most common): resists tension

Elastin : stretchable fiber

Reticular fibers: forms supportive meshwork (bone marrow)

Question 10

What cross-links collagen (2 A1 helical, 1 A2 helical) to form the tensile tetromere collagen strands?

Answer 10

Vitamin C

Question 11

What disease can occur if vitamin C is low?

Answer 11

Scurvy, which is due to weakened CT by weaked/malformed collagen

Question 12

What is Ehlers-Danlos Syndrome?

Answer 12

Abnormal collagen synthesis leading to weak collagen fibers. Hereditary disease in enzymes to make vitamin C

Question 13

What autosomal dominant disorder occurs when there is a mutation in the fibrillin-I gene of elastin fibers, making the elastin weak?

Answer 13

Marfan’s Syndrome

Question 14

What are some common signs of marfan’s syndrome?

Answer 14

skeletal problems: patients are tall with long arms/legs

cardiovascular problems (dissecting aneurysms/ mitral prolapse)

Question 15

Chondoitin, heparan, and keratan sulfates are all part of what group of the ECM?

Answer 15

They are all proteoglycans which are linked together by hyaluronan (hyaluronic acid).

Question 16

Cytokines, Growth factors, and structural proteins such as fibronectin and laminins are all examples of what part of ECM?

Answer 16

Glycoproteins

Question 17

What is unique of embryonic connective tissue (3)?

Answer 17

1. rich in ECM (not in density of cells)
2. rich in mesenchymal stem cells
3. Not many collagen/reticular fibers (wharton’s jelly)

Question 18

What can adult mesenchymal stem cells differentiate into (bone marrow) (5)?

Answer 18

fibroblasts
muscle cells (skeletal/smooth)
osteoblasts
chondroblasts
adipocytes
all depend on location and signaling to become the above

Question 19

What are the 3 types of loose and dense connective tissues?

Answer 19

Loose: Areolar, Adipose, Reticular
Dense: Dense irregular CT, dense regular CT, elastic CT

Question 20

Loose areolar CT

Answer 20

Have both fixed (fibroblasts/adipocytes) and wandering cells from circulation such as macrophages/mast cells.

Question 21

What do loose connective tissues do and where can they be found?

Answer 21

They support and bind tissues, hold body fluids, defends against infection

Found beneath membranous epithelia, around blood vessels, muscles and nerves

Question 22

What is specific to adipose CT?

Answer 22

Abundant adipocytes and sparse ECM

Provides energy and insulates against heat loss

Found under skin and around organs

Question 23

What does white fat do?

Answer 23

Functions in energy storage, insulation, cusioning vital organs and hormone secrection

Question 24

What does brown fat do?

Answer 24

Key thermogenic tissue due to abudance of mitochondria, abundant in newborns and reduced in adults

Question 25

What is specific to reticular connective tissue?

Answer 25

Rich in reitcular fibers (looks like spider web)

open framework to hold most free cells

Found in liver, BM, LN, and spleed where mesh forms to hold blood cells

Question 26

What is specific of dense irregular connective tissue?

Answer 26

ECM is tightly packed (ALOT) and running in random pattern

Fibroblasts are principle cell type

Found in dermis of skin, perichondrium and periosteum

Question 27

What is specific of dense regular connective tissue?

Answer 27

ECM tight packed and all in same order, fibroblast are cell type

Resists pulling forces and poorly vascularized

Found in tendons, ligaments, aponeuroses, dense fascia

Question 28

What is specific of elastic CT?

Answer 28

Contains lots of elastic fibers, allows recoil of tissue following stretching

found in blood vessel walls, bronchiole tubes, and special ligaments (ligamentum nuchae)

Question 29

What is the main function of fibroblasts?

Answer 29

To produce collagen, elastin, reticular fibers, proteoglycans and glyocproteins in ECM

Question 30

What is the function of macrophages?

Answer 30

From blood monocytes, function in phagocytosis and destruction of bacteria, damages or sick cells

Question 31

What is the function of mast cells?

Answer 31

Release chemicals like histamine that mediate the allergic response, and heparin.

important in wound healing and angiogenesis

Question 32

What is unique of plasma cells and what is their function?

Answer 32

Differentiated from B-lymphocytes, function is to produce antibodies that mediate immunity, contain golgi aparatus