chapter 3

Question 1

What is mitotic delay?

Answer 1

delay in the entry of cells into mitosis

Question 2

What is vivo?

Answer 2

living organism

Question 3

what is vitro?

Answer 3

artificial environment (glassware)

Question 4

what is mitotic overshoot?

Answer 4

Mitotic overshoot occurs after irradiation. The population of cells in mitosis is disturbed and the cells that were in mitosis at the time complete their division, but those about to enter division are delayed in G2. The mitotic indexes decreases for a period of time as some cells are stopped from proceeding through mitosis at their appointed time. If the dose is low enough, cells can recover from the delay and proceed through mitosis. The increase in the number of cells undergoing mitosis causes a mitotic overshoot.

Question 5

what cell cycle is the most sensitive?

Answer 5

mitosis

Question 6

what does tissue/organ response depends on 2 factors

Answer 6

1. various cell populations in that
   tissue or organ.
2. The turnover kinetics of each population in the tissue

Question 7

how long is mitosis?

Answer 7

about an hour

Question 8

what does bergonie and tribondeau study?

Answer 8

the role of cell division in radiation response

Question 9

what is the law of radiosensitivity and the meaning

Answer 9

the radiosensitivity of cells is directly proportional to their reproductive activity and inversely proportional to their degree of differentiation.

the more they reproduce, the more sensitive. mitosis is the most sensitive.

Question 10

observations based on the physician report are:

Answer 10

1. x -rays appeared to destroy cells of tumor w/o permanently harming adjacent healthy tissue
2. some tissues were damaged by doses of radiation that did not appear to harm other tisses

Question 11

bergonie and tribondeau performed experiments on rodent testicles in which the tests contains

Answer 11

immature spermatogonia and spermatocytes and also mature cells(spermatozoa);these populations differ both in function and mitotic activity.

Question 12

hypothesis

Answer 12

ionizing radiation is more effective against cells that are actively dividing, are undifferentiated and have a long dividing future.

Question 13

bergonie and tribondeau defined cell sensitivity

Answer 13

terms of specific cellular characteristics, mitotic activity and differentiation, rather than on radiation

Question 14

what is a differentiation cell?

Answer 14

a mature cell. it is specialized and more resistant to radiation effect.

Question 15

what is a undifferentiated cell?

Answer 15

a cell that has a few specialized characteristics.

it is a immature cell (like a baby)

specialized functionally and/or morphol-
ogically (structurally)

Question 16

various stages of differentiation example

Answer 16

testis

Question 17

differentiated cell example

Answer 17

erythrocyte (RBC), no nucleus

Question 18

undifferentiated example

Answer 18

erythroblast, stem cell for RBC, present in bone marrow, supplies cells which will differentiate to become erythrocytes.

Question 19

3 categories of cell populations

Answer 19

stem cell-immature cell
transit cell-teenager cell
static population-senior citizen

Question 20

stem cell population

Answer 20

divide to maintain own population(self-renewal) and produce cells for another population

undifferentiated cell

ex.cells in bone marrow, basal cell in epidermis of skin, cells in crypts, spermatogonia in testis.

Question 21

transit population

Answer 21

move from 1 place to another

may or may not divide while in transit

ex. nucleated red cell(dividing cell) and reticulocyte in bone marrow (non dividing) cell that doesn’t divide

Question 22

static population

Answer 22

loses cells throughout the life of the organism

fully differentiated cells

ex. adult nervous tissue and muscle

radioresistant

Question 23

The process by which immature spermatogonia become mature spermatozoa is termed

Answer 23

differentiation

Question 24

The spermatozoon is the that is morphologically and functionally specialized

Answer 24

mature, nondividing cell

Question 25

5 classes of Mammalian cell population

Answer 25

1. VIM 2. DIM 3. Multipotentional Connective Tissue Cells 4. RPM 5.FPM

Question 26

Does high let has a shoulder?

Answer 26

No, high let doesn't have a shoulder.it goes straight down.

Question 27

VIM

Answer 27

Vegetative Intermitotic cells a. most radiosensitive and more differentiate. b. rapidly dividing c. most radiosensitive group cells ex. basal cells of epidermis, erthyroblasts,

Question 28

DIM

Answer 28

Differentiating Intermitotic Cells -produced by division of VIM cells -actively mitotic but more differentiated than VIM - ex. type B spermatogonia

Question 29

Multipotential Connective Tissue

Answer 29

a. Divide irregularly b. More differentiated than DIM c. Intermediate in radiation sensitivity ex. endothelial cells, fibroblasts

Question 30

RPM

Answer 30

Reverting Postmitotic Cells a. Normally do not undergo mitosis b. Retain capability to divide under special circumstances c.long-lived cells ex. liver cells, mature lymphocyte

Question 31

FPM

Answer 31

Fixed Postmitotic Cells a. Do not divide b. Highly differentiated c. Resistant to radiation ex. muscle cells,RBCs, spermatozoa

Question 32

Parenchymal compartment

Answer 32

cells characteristic of that individual tissue organ

Question 33

stromal compartment

Answer 33

composed of connective tissue and vasculature which supports the organ structure.

Question 34

parenchymal compartment

Answer 34

may be comprised of more than 1 category of cells ex. testis another example is hematopoietic bone marrow (stem cells) circulating blood cells; skin and intestinal tract

Question 35

hypothesis

Answer 35

the difference in time it takes for damage to be expressed is simply due to differences in turnover kinetics of critical target cells in different tissues

Question 36

how many normal tissues can be divided into 2 categories

Answer 36

acutely responding and late responding normal tissues

Question 37

acute responding-

Answer 37

show injury within a few months after radiation is completed b/c they are self-renewal tissues containing rapidly dividing stem cell population ex. breast cancer people getting radiation. you will see redness.

Question 38

what are examples of acute responding

Answer 38

bone marrow, skin, intestine, and testis

Question 39

late responding

Answer 39

injury not expressed for at least 3 months or longer b/c they contain slow dividing cell populations. not critical ex. lung, kidney

Question 40

assays of radiation damage are divided into 3 categories

Answer 40

1. clonogenic 2. functional 3.lethality

Question 41

d0 is 1.2

Answer 41

radiosensitive b/c number is low