Chronic Inflammation 4

Question 1

__________: refers to the restoration of tissue architecture and function after an injury.

Answer 1

Repair

Question 2

Rapier occur by two reaction:

Answer 2

1. Regeneration
2. Scar formation

Question 3

tissues are able to replace the damaged components and essentially return to a normal state; this process is called

Answer 3

Regeneration

Question 4

If the injured tissues are incapable of complete restitution, or if the supporting structures of the tissue are severely damaged, repair occurs by laying down of connective (fibrous) tissue, a process termed healing that results in

Answer 4

Scar formation

Question 5

The term ___________ is most often used to describe the extensive deposition of collagen that occurs in the lungs, liver, kidney, and other organs as a consequence of chronic inflammation.

Answer 5

fibrosis

Question 5

fibrous scar is not normal, it provides enough structural ________ that the injured tissue.

Answer 5

stability

Question 6

If fibrosis develops in a tissue space occupied by an inflammatory exudate it is called _________ (as in organizing pneumonia affecting the lung).

Answer 6

organization

Question 7

Several cell types proliferate during tissue repair. These include:

Answer 7

1. Remnant of injury tissue
2. Vascular endothelial cell to provide nutrients for repair process
3. Fibroblast - source of fibrous connective tissues that form scar to fill defect

Question 8

he proliferation of these cell types is driven by proteins that are collectively called _______

Answer 8

Growth factor

Question 9

normal size of cell populations is determined by a balance of:

Answer 9

• cell proliferation
• death by apoptosis
• differentiation cell from stem cell

Question 10

Repair involves the proliferation of various cells, and close interactions between cells and the _____________.

Answer 10

extracellular matrix (ECM)

Question 11

The key processes in the proliferation of cells are _________ and _________.

Answer 11

DNA replication , mitosis

Question 12

The sequence of events that control these two processes is known as the

Answer 12

Cell cycle

Question 13

The cycle consists of:

Answer 13

The presynthetic growth phase 1 (G1).
The DNA synthesis phase (S).
The premitotic growth phase 2 (G2).
The mitotic phase (M).

Question 14

Non-dividing cells are either in cell cycle arrest in _____ or they exit the cycle to enter a phase called _____.

Answer 14

G1 , G0

Question 15

Further progression is determined by the ability of the cell to traverse an intrinsic quality control mechanism for cell integrity, known as ___________.

Answer 15

checkpoint control

Question 16

Progression through the cell cycle from G1 is regulated by proteins called ________, which form complexes with enzymes
called _________________

Answer 16

Cyclins , cyclin-dependent kinases (CDKs).

Question 17

The ability of tissues to repair themselves is critically influenced by their ______________.

Answer 17

intrinsic proliferative capacity

Question 18

the tissues of the body are divided into three groups:

Answer 18

1. Continuously dividing tissues.
2. Stable tissues.
3. Permanent tissues.

Question 19

1. Continuously Dividing Tissues:

Answer 19

Cells of these tissues (also known as labile tissues) are continuously being lost and replaced by maturation from stem
cells and by proliferation of mature cells.

Question 20

Labile cells include:

Answer 20

1. Hematopoietic cell ( bone marrow)
2. Surface epithelial ( stratified squamous surfaces of the skin, oral cavity, vagina, and cervix)
3. Cuboidal epithelial ( salivary glands, pancreas, biliary tract )
4. Columnar epithelial ( gastrointestinal tract, uterus, and fallopian tubes )
5. Transitional epithelial ( urinary tract )

Question 21

2. Stable tissue

Answer 21

Cells of these tissues are quiescent (in the G0 stage of the cell cycle) and have only minimal replicative activity in their normal state.

Question 22

Stable cells constitute the parenchyma of most solid tissues, such as ________, _______, and ________.

Answer 22

liver, kidney, and pancreas, endothelial cells, fibroblasts, and smooth muscle cells.
- these cells are capable of proliferating in response to injury or loss of tissue mass

Question 23

With the exception of _______, stable tissues have a limited capacity to regenerate after injury.

Answer 23

liver

Question 24

Permanent Tissues:

Answer 24

The cells of these tissues are considered to be terminally differentiated and nonproliferative in postnatal life. - The majority of neurons and cardiac muscle cells belong to this category.

Question 25

_________ is usually classified as a permanent tissue, but ________ attached to the endomysial sheath provide some regenerative capacity for this tissue

Answer 25

Skeletal muscle, satellite cells

Question 26

In permanent tissues, repair is typically dominated by _______.

Answer 26

scar formation

Question 27

Stem cell differentiation

Answer 27

1. Epidermal stem cells located in the bulge area of the hair follicle = hair follicle and the epidermis. 2. Intestinal stem cells are located at the base of a colon crypt, above Paneth cells = enterocyte. 3. Liver stem cells (commonly known as oval cells) are located in the canals of Hering = hepatocyte. 4. Corneal stem cells are located in the limbus region, between the conjunctiva and the cornea.

Question 28

Stem cells are characterized by two important properties:

Answer 28

1. Self-renewal capacity. 2. Asymmetric replication.

Question 29

Stem cells with the capacity to generate multiple cell lineages (___________) can be isolated from embryos and are called _________(ES) cells.

Answer 29

pluripotent stem cells , embryonic stem

Question 30

The Nature And Mechanisms Of Action Of Growth Factors: Cell proliferation can be triggered by many chemical mediators, such as ________, _______, and _______.

Answer 30

growth factors, hormones, cytokines

Question 31

Expansion of cell populations usually involves:

Answer 31

1. Increase in cell size (growth). 2. Cell division (mitosis). 3. Protection from apoptotic death (survival).

Question 32

Function of growth factor , pleiotropic effects

Answer 32

Simulating cellular proliferation. stimulate migration. differentiation and contractility. enhance the synthesis of specialized proteins (such as collagen in fibroblasts).

Question 33

A growth factor may act on a specific cell type or on multiple cell types:

Answer 33

1. induce cell proliferation by binding to specific receptors. 2. Affecting the expression of genes whose products typically have several functions. 3. Relieve blocks on cell cycle progression (thus promoting replication). 4. Prevent apoptosis, and they enhance the synthesis of cellular proteins in preparation for mitosis.

Question 34

A major activity of growth factors is to stimulate the function of

Answer 34

growth control genes, many of which are called protooncogenes because mutations in them lead to unrestrained cell proliferation characteristic of cancer (oncogenesis).

Question 35

- Many of the growth factors that are involved in repair are produced by _______ that are recruited to the site of injury or are activated at this site, as part of the inflammatory process.

Answer 35

leukocytes

Question 36

growth factor can have _________ on the same cell depending on its concentration

Answer 36

opposite effects - An example of such a growth factor is transforming growth factor-β (TGF-β).

Question 37

Other growth factors are produced by the _________ or the __________cells in response to cell injury or loss.

Answer 37

parenchymal cells , stromal (connective tissue)

Question 38

Signaling Mechanisms of Growth Factor Receptors:

Answer 38

1. Autocrine signaling: in which a substance acts predominantly (or even exclusively) on the cell that secretes it. 2. Paracrine signaling: in which a substance affects cells in the immediate vicinity of the cell that released the agent. 3. Endocrine signaling: in which a regulatory substance, such as a hormone, is released into the bloodstream and acts on target cells at a distance.

Question 39

——-

Answer 39

Receptor proteins are generally located on the cell surface, but they may be intracellular; in the latter case, the ligands must be sufficiently hydrophobic to enter the cell