Cellular adaptation, tissue regeneration, disordered growth and tumours

Question 1

cellular adaptation

Answer 1

cells changing in some way to become better suited to new environments or conditions

Question 2

main methods of cellular adaptation

Answer 2

hyperplasia, hypertrophy, atrophy and metaplasia

Question 3

Hyperplasia

Answer 3

Increase in the number of cells in an organ or tissue resulting in increased volume

Question 4

Mechanisms of hyperplasia

Answer 4

increased production and expression of growth factors which are excitatory agonists for signalling pathways that activate transcription factors to increase gene expression and hence cell proliferation

Question 5

Hypertrophy

Answer 5

An increase in the size of cells due to more structural components, resulting in an increase in the size of the organ

Question 6

causes of hypertrophy

Answer 6

increased functional demand (exercise) or hormonal stimulation (angiotensin, noradrenaline, insulin-like growth factor)

Question 7

Atrophy

Answer 7

the shrinkage (reduced size) of an organ 
or tissue from a decrease in cell size and number due to apoptosis

Question 8

Causes of Atrophy

Answer 8

decreased workload (restriction, bed rest, astronauts in space), loss of innervation (nerve damage), diminished blood supply, lack of nutrition or endocrine stimulation

Question 9

Healing responses after injury

Answer 9

regeneration (same function), scar formation and fibrosis (loss of function) by the deposition of collagen

Question 10

what does regeneration and repair depend on?

Answer 10

The ability of the tissue to regenerate, The extent of the injury

Question 11

terminally differentiated

cells

Answer 11

Differentiated cells incapable of replication

Question 12

Stem cells

Answer 12

self-renewing cells that are capable of differentiating into a range of cell types

Question 13

stem cell generation from fertilisation

Answer 13

zygote - divides to form blastocysts. inner cell mass, full of embryonic stem cells, generates the embryo

Question 14

totipotent

Answer 14

differentiates into any cell type and can proliferate indefinitely

Question 15

Induced pluripotent stem cells

Answer 15

Differentiated cells of adult tissues can be

reprogrammed to become pluripotent

Question 16

Impact of stem cell research on

Biology and Medicine

Answer 16

regenerate damaged organs - important to avoid rejection from donors. models for human diseases on knockout mice

Question 17

Metaplasia

Answer 17

A reversible change in which one adult cell type is replaced by another

Question 18

Dysplasia

Answer 18

disordered growth - architecture of the tissue may be disordered

Question 19

Characteristics of dysplasia

Answer 19

Loss in the uniformity and orientation. pleomorphism (strange nuclear size/shape) e.g. hyperchromatic nuclei that are abnormally large. mitotic figures in abnormal locations (not in basal layers)

Question 20

Anaplasia

Answer 20

Lack of differentiation - marker of malignancy

Question 21

Morphological changes of

anaplasia

Answer 21

Pleomorphism, Abundance of DNA, Mitoses, Loss of polarity

Question 22

Neoplasia

Answer 22

process of new growth

Question 23

tumour

Answer 23

abnormal mass of tissue

Question 24

Histogenetic classification of tumours

Answer 24

based on cell origin

Question 25

benign epithelial tumours

Answer 25

papillomas or adenomas

Question 26

Benign connective tissue tumours

Answer 26

prefix denotes cell of origin

Question 27

Malignant epithelial tumours

Answer 27

carcinomas

Question 28

Malignant connective tissue tumours

Answer 28

sarcomas

Question 29

benign tumours

Answer 29

slow growth rate, regular edges, resemble parent tissue, capsulated by fibrous tissue - readily palpable and early movable surgically

Question 30

Malignant tumours

Answer 30

rapid growth rate, irregular edges, metastasised, Variable histological resemblance to the parent tissue

Question 31

Metastases

Answer 31

tumour implants discontinuous with the primary tumour

Question 32

Pathways of metastasis

Answer 32

direct seeding, lymphatic spread, haematogenous spread and implantation after operations

Question 33

what are the four classes of regulatory genes that are the principal targets of genetic damage

Answer 33

The growth promoting oncogenes (more cells), The growth inhibiting tumour suppressor genes (less preventing growth), Genes that regulate programmed cell death (less cells killed off), Genes involved in DNA repair (less correction of damaged cells)