Connective Tissues II

Question 1

Types of immigrant blood-derived cells

Answer 1

a. lymphocytes
b. macrophages
c. neutrophils and eosinophils
d. mast cells
e. osteoclasts

Question 2

Lymphocytes are

Answer 2

central to acquired immunity to foreign organisms/viruses/ materials

Question 3

Macrophages are _______ cells that _______ cells, ECM, and other non-cellular material. Macrophages are also critical regulatory cells that _______

Answer 3

• large “engulfing”
• phagocytose (eat by endocytosis)
• secrete and respond to numerous extracellular signals

Question 4

Macrophage-produced signals have numerous functions that include:

Answer 4

• stimulation of enodothelial cells to induce blood vessel growth and formation (blood vessel formation = angiogenesis)
• immune cell migration and function
• fibroblast activation
• blood vessel permeability

Question 5

Macrophages have several important physiological functions:

Answer 5

(i) engulf (phagocytose) invading microorganisms
(ii) promote blood vessel formation (angiogenesis)
(iii) remodel damaged tissue
(iv) remodel normal developing tissue and organs as part of their morphogenesis.

Question 6

Neutrophils and eosinophils, important for

Answer 6

defense against microorganisms

Question 7

Mast cells are secretory cells that, when stimulated by immune responses, _______; thus mast cells are important in _______ and _______

Answer 7

• release various substances, including vasodilators that promote swelling in connective tissue
• edema
• allergic hypersensitivities

Question 8

Osteoclasts are _______ cells that appear to be derived from _______ and are very similar to macrophages. However they specifically function in _______

Answer 8

• phagocytic
• blood monocytes
• bone resorption and remodeling, not general phagocytosis

Question 9

precursors or differentiated blood cells must traverse the _______ to enter connective tissues

Answer 9

endothelium of blood vessels

Question 10

Macrophages and osteoclasts derive and differentiate from _______

Answer 10

-blood monocytes

Question 11

Mast cells differentiate from

Answer 11

blood basophils

Question 12

Lymphocytes, neutrophils and eosinophils come from

Answer 12

similar if not identical differentiated cell types in the blood

Question 13

_______ are the central CT cell type that makes the components of the extracellular matrix of most connective tissues

Answer 13

Fibroblasts

Question 14

Fibroblasts are secretory machines that produce the

Answer 14

fibrous proteins, proteoglycans, and other components of the extracellular matrix (the ECM)

Question 15

Fibroblasts are capable of _______ to produce new fibroblasts, and possibly _______

Answer 15

• cell division
• new fibroblasts
• other connective tissue types.

Question 16

The _______ and _______ of fibroblasts are highly regulated. A common response to a laceration or other tissue injury is a stimulation of _______, and a stimulation of _______. In situations where injury is severe, scarring of tissues results from the _______

Answer 16

• secretory activity
• proliferation
• proliferation of fibroblasts
• ECM production
• hypertrophy (increased growth) of fibroblast-dependent connective tissue.

Question 17

Recent evidence shows that fibroblasts in different CT’s express _______. Even within a single CT region,_______

Answer 17

• different sets of markers and regulatory proteins

- several fibroblast “types” have been observed

Question 18

_______ methods are required to detect fibroblast differences; by _______ most fibroblasts look _______. The different fibroblast states are likely responsible for the enormous variation in ECM structure and composition.

Answer 18

• Immunohistological
• standard histological staining (e.g. H&E)
• very similar throughout the body

Question 19

fibroblasts are developmentally flexible: They can transform (differentiate) into other connective tissue cell types such as

Answer 19

adipocytes, smooth muscle cells, chondrocytes, and osteoprogenitor cells

Question 20

small numbers “less determined” _______ remain in many adult connective tissues, and these cells may be the primary precursors for these different cell types in vivo. These may originate in the _______, like blood cells, but they produce different cell lineages from the _______

Answer 20

• mesenchymal stem cells (MSCs)
• bone marrow
• hematopoietic stem cells

Question 21

MSCs produce _______, at least under normal conditions. At a minimum, it seems likely that fibroblasts or MSCs differ in their _______, given the apparent diversity of fibroblasts.

Answer 21

• CT family cells

- developmental potential