cell adaptations

Question 1

define necrosis

Answer 1

a pathological cellular or tissue death in a living organism, irrespective of cause

Question 2

define apoptosis

Answer 2

a form of normal or pathological individual cell death characterised by activation of endogenous endonucleases

Question 3

define pyknosis

Answer 3

shrinkage of the nucleus in a necrotic cell

Question 4

define karyorrhexis

Answer 4

fragmentation of nuclear material

Question 5

define free radicals

Answer 5

chemical radicals characterised by unpaired electrons in the outer shell and therefore highly reactive

Question 6

define ischaemia

Answer 6

an inadequate blood supply to an organ or part of it

Question 7

define infarction

Answer 7

death of a tissue due to insufficient blood supply

Question 8

define atrophy

Answer 8

decrease in size and no. of cells, resulting in a decrease in tissue and organ size

Question 9

define hypertrophy

Answer 9

increase in cell size without division

Question 10

define hyperplasia

Answer 10

increase in the number of normal cells

Question 11

define metaplasia

Answer 11

replacement of one fully differentiated cell type with another

Question 12

define dysplasia

Answer 12

increased cell proliferation, abnormal morphology and decreased differentiation

Question 13

list the types of necrosis

Answer 13

coagulative
liquefactive
caseous
gangrene
fibrinoid
fat

Question 14

define dystrophic calcification

Answer 14

calcification (deposition of calcium) occurring in damaged tissue

Question 15

define metastatic calcification

Answer 15

calcification (deposition of calcium) in previously normal tissue due to disturbance in calcium/phophorus metabolism

Question 16

explain pathological vs physiological

Answer 16

physiological = 'normal' change
pathological = 'abnormal'

Question 17

what are the causes of atrophy?

Answer 17

atrophy of disuse
denervation atrophy
ischaemic atrophy
malnutrition atrophy
endocrine-related atrophy

Question 18

what is ischaemic atrophy?

Answer 18

reduction of blood supply to tissue

Question 19

what is the mechanism of hypertrophy?

Answer 19

progressive stimulation of myocytes

signalling - either mechanical via receptors or endocrine via hormones

Question 20

what is the mechanism of hyperplasia?

Answer 20

growth factor-driven proliferation

sometimes by increased output of new cells from tissue stem cells

Question 21

what are the types of physiological hyperplasia?

Answer 21

1. Hormonal hyperplasia - happens to increase functional capacity of a tissue when needed, under the influence of hormones
2. Compensatory hyperplasia - increases tissue mass after damage or partial resection

Question 22

what causes pathological hyperplasia?

Answer 22

either excesses of hormones or growth factors acting on target cells
e.g. endometrial or benign prostatic hyperplasia

Question 23

what is the mechanism of metaplasia?

Answer 23

reprogramming of stem cells or of undifferentiated mesenchymal cells present in connective tissue