Connective tissue 1

Question 1

connective tissue is composed of ?

Answer 1

1. fibroblasts
2. extracellular matrix
3. ground substance

Question 2

describe mesenchyme cells

Answer 2

consists of a population of undifferentiated cells, generally elongated but with many shapes, having large euchromatic nuclei and prominent nucleoli that indicate high levels of synthetic activity.

Question 3

________ -______ are surrounded by an ECM that they produced and that consists largely of a simple ground substance rich in hyaluronan (hyaluronic acid), but with very little collagen

Answer 3

mesenchymal cells

Question 4

connective tissue cell types include:

Answer 4

1. fibroblasts
2. macrophages
3. mast cells
4. plasma cells
5. adipocytes
6. leukocytes

Question 5

what are fibroblasts?

Answer 5

typically have large active nuclei and eosinophilic cytoplasm that tapers off in both directions along the axis of the nucleus, a morphology often referred to as “spindle-shaped

Question 6

what is the difference between inactive and active fibroblasts?

Answer 6

Active fibroblasts have large, euchromatic nuclei and basophilic cytoplasm, while inactive fibroblasts (or fibrocytes) are smaller with more heterochromatic nuclei

Question 7

what is myofibroblasts contractile?

Answer 7

Fibroblasts involved in wound healing call myofibroblasts

Contractile. Pull edges of wound together by contraction like smooth muscle. After role completed, under apoptosis.

Question 8

what are mast cells?

Answer 8

• components of loose connective tissues, often located near small blood vessels
• They are typically oval shaped, with cytoplasm filled with strongly basophilic granules

Question 9

mast cell secretion is triggered by ____ ______ to certain antigens and allergens

Answer 9

re exposure

Question 10

plasma cells are large ovoid cells with _________ cytoplasm

Answer 10

basophilic

Question 11

plasma cells are often more abundant in ________ tissues

Answer 11

infected

Question 12

Plasma cells leave their sites of origin in lymphoid tissues, move to connective -tissue, and produce antibodies that mediate immunity ( T or F)

Answer 12

TRUE

Question 13

what are the 3 fibre types?

Answer 13

1. collagen fibres
2. Reticular fibres
3. Elastic fibres

Question 14

describe type I collagen

Answer 14

the most abundant collagen, assemble to form extremely strong fibrils, which are then bundled together further by other collagens into much larger structures called collagen fibers.

Question 15

describe collagen I synthesis

Answer 15

Hydroxylation and glycosylation of procollagen α chains and their assembly into triple helices occur in the RER, and further assembly into fibrils occurs in the ECM after secretion of procollagen

Question 16

describe collagen I assembly

Answer 16

1.  Rodlike triple-helix collagen molecules, each 300 nm long, self-assemble in a highly organized, lengthwise arrangement of overlapping regions.
2.  The regular, overlapping arrangement of subunits continues as large collagen fibrils are assembled.
3.  This structure causes fibrils to have characteristic cross striations with alternating dark and light bands when observed in the EM.
4.  Fibrils assemble further and are linked together in larger collagen fibers visible by light microscopy.
5.  Type I fibers often form into still larger aggregates bundled and linked together by other collagens.

Question 17

what is the function of reticular fibres?

Answer 17

These fibers serve as a supportive stroma in most lymphoid and hematopoietic organs and many endocrine glands. The fibers consist of type III collagen that is heavily glycosylated

Question 18

Can HE stain be used on elastic fibres?

Answer 18

NO

Question 19

the major componant of elastic fibres is ?

Answer 19

elastin polypeptides

Question 20

Most of the cross-links between elastin subunits consist of covalent, cyclic structure called ___________ each of which involves four converted lysines in two elastin molecules

Answer 20

desmosine

Question 21

what are the 3 classes of ECM ground substance?

Answer 21

1. glycosaminoglycans (GAG)
2. Proteoglycans
3. Multiadhesive glycoproteins

Question 22

describe glycoproteins

Answer 22

usually globular proteins with branched oligosaccharide side-chains. Their polypeptide content is generally greater than their polysaccharide content.

Question 23

describe proteoglycans

Answer 23

contain a core of protein with one or many side chains of sulfated GAGs as well as branched oligosaccharides, generally having more carbohydrate than do glycoproteins

Question 24

_______ is concentrated in the basil lamina of the stratified epithelium and in the external laminae surrounding cross-sectioned nerves and muscle fibers

Answer 24

laminin

Question 25

A fine network of _______ is localized more diffusely throughout the ECM

Answer 25

fibronectin

Question 26

how does fluid move in connective tissue?

Answer 26

Water normally passes through capillary walls into the ECM of surrounding connective tissues primarily at the arterial end of a capillary, because the hydrostatic pressure is greater than the colloid osmotic pressure

Question 27

hydrostatic pressure decreases toward the venous end of the capillary ( T or F)

Answer 27

TRUE

Question 28

The fall in hydrostatic pressure parallels a decrease in osmotic pressure of the capillary blood because the plasma protein concentration increases as water is pushed out across the capillary wall. (FALSE)

Answer 28

FALSE (increase)

Question 29

what are the types of connective tissue?

Answer 29

1. loose
2. dense (regular or irregular)
3. reticular
4. Cartilage
5. Bone

Question 30

________ _______ of type III collagen are produced and enveloped by the reticular cells, forming an elaborate network through which interstitial fluid or lymph and wandering cells from blood pass continuously

Answer 30

reticular fibres

Question 31

what is the function of connective tissue?

Answer 31

support and connect

Question 32

Connective tissue is composed primarily of extracellular material rather than cells (T or F)

Answer 32

TRUE

Question 33

ECM is composed of _______ and ______

Answer 33

ground substance and fibres