Cellular adaptations

Question 1

What 4 actions can the chemical signals that regulate cellular proliferation have on cells?

Answer 1

resist apoptosis
die
divide
differentiate

Question 2

two ways in which a cell popn increases its numbers

Answer 2

shortening of the cell cycle

the conversion of quiescent cells into cells that enter the cell cycle (proliferating cells)

Question 3

Two ways in which mitosis is regulated?

Answer 3

checkpoints- esp the restriction checkpoint (most critical checkpoint)
Cyclins and cyclin dependent kinases- Cyclins bind to cyclin dependent kinases to allow the cell to pass through to the next cell cycle change

Question 4

If activated, what effects does the restriction checkpoint have on the cell? 3

Answer 4

delays mitosis
triggers DNA repair
Can trigger apoptosis

Question 5

define hyperplasia

Answer 5

Increase in cell number

Question 6

define hypertrophy

Answer 6

increase in cell size

Question 7

define atrophy

Answer 7

decrease in cell size and number

Question 8

define metaplasia

Answer 8

change of on differentiated cell type to another

Question 9

In what types of tissue does hyperplasia occur and name two causes of it

Answer 9

labile and stable tissue

Causes: increased functional demand or hormonal stimulation

Question 10

What is the risk of hyperplasia?

Answer 10

increases the risk of mutations and neoplasia development

Question 11

Give two physiological examples of hyperplasia?

Answer 11

Bone marrow increases production of erythrocytes in response to hypoxia
proliferative endometrium under oestrogen influence

Question 12

Give two pathological examples of hyperplasia?

Answer 12

goitre

eczema

Question 13

In what type of tissue does hypertrophy occur

Answer 13

All types but especially permanent

Question 14

two causes of hypertrophy?

Answer 14

increased functional demand or hormonal stimulation (same as hyperplasia causes))

Question 15

WHat happens to the cell in hypertrophy?

Answer 15

increased number of structural compinents so that the workload is shared between a greater number of components

Question 16

Define compensatory hypertrophy. Give an example of this

Answer 16

when one of two organs undergoes hypertrophy because the other organ has been injured so makes up for other organ

eg. a kidney transplant (the donor)

Question 17

Name two physiological examples of hypertrophy

Answer 17

skeletal muscle

pregnancy

Question 18

name two pathological examples of hypertrophy

Answer 18

bowel wall when the prostate gland compresses urethra

cardiac hypertrophy

Question 19

What two processes usually occur in organ shrinkage

Answer 19

atrophy and apoptosis

Question 20

give one example of physiologicaL ATROPHY

Answer 20

ovary after menopause

Question 21

Give 8 examples of pathological atrophy

Answer 21

loss of innervation (Eg. median nerve damage leads to atrophy of muscle in the hand)
Loss of blood supply (EG. thinning of the skin in peripheral vascular disease)
Aging
Decreased demand or workload (Eg. disuse muscle atrophy)
Pressure (Brain tumour)
Inadequate nutrition
Decreased endocrine stimulation
persistent injury (Eg. chronic inflammation)

Question 22

Give an examples of atrophy of the extracellular matreix

Answer 22

osteoporosis

Question 23

What is metaplasia due to? What is it often a prelude to? In what tissues does it occur in? Between what types of layers do you not get metaplasia

Answer 23

altered stem cell differentiation
dysplasia and cancer
occurs in labile and stable tissue
you don’t get metaplasia across germ layers

Question 24

Give three examples of metaplasia

Answer 24

Barretts Oesophagus: Stratified squamous epithelium to gastric glandular epithelium due to persistent acid reflux
Bronchial Pseudostratified epithelium –>stratified squamous epithelium due to cigarette smoke
Splenic metaplasia when bone marrow is damaged to take over the role of red blood cell production

Question 25

Define aplasia. Give an example of it

Answer 25

complete failure of an organ to develop or used to describe an organ where the cells have ceased to proliferate (eg. bone marrow in aplastic anaemia)

Question 26

Define hypoplasia

Answer 26

The underdevelopment of a tissue or organ at the embryonic stage

Question 27

Define involution and give an example of it?

Answer 27

normal programmed shrinkage of an organ, eg. uterus after childbirth

Question 28

Define reconstitution

Answer 28

replacement of a body part

Question 29

Define atresia

Answer 29

No orifice

Question 30

Defien dysplasia

Answer 30

Abnormal maturation of cells in a tissue. Often precancerous