Session 7 - Cellular Adaptations

Question 1

What are the 3 checkpoints in the cell cycle?

Answer 1

R point towards end of G1
G1/S point
G2/M point

Question 2

What does p53 do?

Answer 2

Suspends cell cycle and trigger DNA repair mechanisms, if cannot be repaired, then apoptosis

Question 3

What is does G1/S transition checkpoint check for?

Answer 3

DNA damage before DNA replication

Question 4

What does G2/M checkpoint check for?

Answer 4

DNA damage after DNA replication

Question 5

What does cyclins and cyclin-dependent kinases do?

Answer 5

CDK binds to cyclin to form a complex and it drives the cell cycle by phosphorylating proteins that are critical for progression of cell to the next stage

Question 6

How is the activity of cyclin-CDK a complexes regulated?

Answer 6

CDK inhibitor

Question 7

What are 2 ways growth factors can regulate cell cycle?

Answer 7

Stimulate production of cyclins

Shutting off production of CDK inhibitors

Question 8

What does retinoblastoma protein do?

Answer 8

Acts to prevent DNA replication, so CDKs will phosphorylates it to inhibit it

Question 9

What is hyperplasia?

Answer 9

Increase in number above normal

Question 10

What is hypertrophy?

Answer 10

Increase in size

Question 11

What is atrophy?

Answer 11

Cells become smaller

Question 12

What is metaplasia?

Answer 12

Cells are replaced by a different type

Question 13

What are 2 types of tissues that can undergo hyperplasia?

Answer 13

Labile or stable

Question 14

What are 3 possible causes of physiological hyperplasia?

Answer 14

Increased functional demand
External stimulation
Secondary to pathological cause

Question 15

Why is neoplasia a risk in hyperplastic tissue?

Answer 15

Repeated cell divisions that occur in hyperplasia exposes cell to more mutations

Question 16

What are 2 examples of physiological hyperplasia?

Answer 16

Proliferation endometrium under influence of oxygen

Bone marrow produces erythrocytes due to hypoxia

Question 17

What are 2 examples of pathological hyperplasia?

Answer 17

Eczema

Thyroid goitre in iodine deficiency

Question 18

What are the 3 types of tissue that can undergo hypertrophy?

Answer 18

Labile
Stable
Especially permanent

Question 19

What are 2 examples of physiological hypertrophy?

Answer 19

Skeletal muscle for body builders

Pregnant uterus

Question 20

What are 2 examples of pathological hypertrophy?

Answer 20

Ventricular hypertrophy

Bladder hypertrophy

Question 21

What are 3 possible causes of atrophy?

Answer 21

Reduced supply of growth factors
Reduced supply of nutrients
Reduced functional demand

Question 22

Is tissue atrophy reversible?

Answer 22

Only up to a point

Question 23

What is an example of physiological atrophy?

Answer 23

Ovarian atrophy in post menopausal women

Question 24

What are 8 examples of pathological atrophy?

Answer 24

Reduced functional demand - muscle atrophy after disease
Loss of innervation - wasted hand muscles after nerve damage
Inadequate blood supply - atherosclerosis
Inadequate nutrition - Marasmus
Loss of endocrine stimulation - less oestrogen
Persistent injury
Senile atrophy of brain
Pressure due to enlarging tumors

Question 25

What are 2 types of tissues that can undergo metaplasia?

Answer 25

Labile or stable

Question 26

Why does metaplasia occur?

Answer 26

Adaptive substitution of cells that are sensitive to stress by cell types that can better withstand the environment

Question 27

Is metaplasia reversible?

Answer 27

Yes

Question 28

What is an example of metaplasia due to smoking?

Answer 28

Bronchial pseudostratified ciliated epithelium to stratified squamous epithelium

Question 29

What is an example of metaplasia due to Barrett’s oesophagus?

Answer 29

Persistent acid reflux changes stratified squamous to gastric glandular epithelium

Question 30

What are 2 long term complications of metaplasia?

Answer 30

Can lead to dysplasianand cancer

Question 31

What is aplasia?

Answer 31

Complete failure of specific tissue or organ to develop embryonically

Question 32

What is hypoplasia?

Answer 32

Under or incomplete development of tissue to organ at embryonic stage, inadequate number of cells

Question 33

What is involution?

Answer 33

Normal programmed shrinkage of an organ

Question 34

What is reconstitution?

Answer 34

Replacement of a lost part of body

Question 35

What is atresia?

Answer 35

Congenital imperforation of an opening

Question 36

What is dysplasia?

Answer 36

Abnormal maturation of cells within a tissue, potentially reversible, often pre cancerous