Cellular Adaptations

Question 1

What are growth factors, their role in cellular growth and some examples?

Answer 1

Proteins that function to regulate the cell cycle and cell division

e.g. VEGF, EPO, EGF (epidermal growth factor, GH)

Question 2

What are the diff stages of the cell cycle?

Answer 2

Interphase: G1, S, G2. Mitosis

Question 3

What is the restriction (R) point?

Answer 3

Most critical checkpoint near the end of G1,

majority of cell that pass will complete cell cycle,

point of no return,

altered in cancer,

checkpoint activation delays cells cycle and triggers repair/apoptosis via p53

Question 4

What is the role of cyclins and CDK?

Answer 4

Cell cycle control mechanism

to move forward in cell cycle, cyclin must bind CDK (cyclin dependent kinase) + target protein = activated = phosphorylation of target protein to move on

Question 5

How many times can a cell divide?

Answer 5

61.3

Question 6

What is the role of RB protein?

Answer 6

Retinoblastoma susceptibility protein

substrate target enzyme needing to be phosphorylated for cell cycle to continue past checkpoint

Question 7

Define regeneration

Answer 7

Restitution with no, or minimal evidence that there was a previous injury

Question 8

Which tissues can undergo regeneration and which cannot?

Answer 8

Can = labile/stable tissue e.g. liver, skin.

Cannot = permanent tissue e.g. nerve, skeletal, cardiac

Question 9

Define hyperplasia

Answer 9

Increase in tissue or organ size, by increased cell number

due to increased functional demand or hormonal stim

Under physiological control and is reversible

Question 10

Which tissues can undergo hyperplasia?

Answer 10

Labile or stable tissue

Question 11

Give physiological and pathological examples of hyperplasia

Answer 11

Phy = prolif endometrium by oestrogen, bone marrow prod RBC by hypoxia.

Path = eczema, goitre by iodine def

Question 12

Define hypertrophy

Answer 12

Increased in tissue/organ size due to increased cell size

due to increased functional demand or hormonal control

Question 13

Which tissues can undergo hypertrophy?

Answer 13

Labile, stable but especially permeant tissues

Question 14

Give an example of physiological hypertrophy

Answer 14

Skeletal muscle, pregnant uterus

Question 15

Outline some pathological examples of hypertrophy

Answer 15

ventricles of the heart (heart always slightly hypoxic – cant form enough vessels to maintain O2 demand),

urinary bladder when constricted

Question 16

What is compensatory hypertrophy?

Answer 16

Combination of hypertrophy and hyperplasia – when one organ makes up for the deficit in another

Question 17

Define atrophy

Answer 17

Shrinkage of a tissue/organ due to an acquired decrease in size and/or number of cells

Question 18

Give an example of physiological atrophy

Answer 18

Ovarian atrophy in post-menopausal women

Question 19

Give an example of pathological atrophy

Answer 19

Atrophy of disuse = reduced function demand/workload.

Loss of innervation = denervation atrophy.

Inadequate blood supply/nutrition = gradual process.

Loss of endocrine stim.

Persistent injury.

Ageing = senile atrophy.

Pressure = swelling, ischemia

Question 20

Define metaplasia

Answer 20

Reversible change of one differentiated cell type to another due to altered stem cell differentiation

Question 21

Why does metaplasia occur?

Answer 21

Altered stem cell differentiation – may represent adaptive substitution of cells that are sensitive to stress by cell types better able to withstand the adverse environment

Question 22

Give an example of metaplasia

Answer 22

Smoking = bronchila pseudostratified ciliated epithelium –> stratified squamous epithelium

Barretts oesophagus (reflux) = stratified squamous epithelium –> simple columnar epithelium with goblet cells

Question 23

Define aplasia

Answer 23

Complete failure of tissue/organ to devel

aplasia of bone marrow = aplastic anaemia

Question 24

Define hypoplasia

Answer 24

Undevel/incomplete devel of tissue/organ at embryonic stage, inadequate number of cells

Question 25

Define involution

Answer 25

Form of atrophy

Normal programmed shrinkage of an organ

uterus after childbirth

Question 26

Define reconstitution

Answer 26

Replacement of a lost part of the body

Question 27

Define atresia

Answer 27

No orifice = congenital imperforation of an opening

Question 28

Define dysplasia

Answer 28

Abnormal maturation of cells within a tissue – often pre-cancerous condition

Question 29

What are the causes and complications of left ventricular hypertrophy?

Answer 29

causes = exercise, hypertension, aortic stenosis

complications = heart failure, arrhythmia

Question 30

What are the causes and complications of Barretts oesophagus?

Answer 30

replacement of the normal stratified squamous epithelium lining of the esophagus by simple columnar epithelium with goblet cells

cause = reflux

complications = esophageal adenocarcinoma

Question 31

What is traumatic myositis ossificans?

Answer 31

heterotopic ossification (calcification) of muscle

inappropriate differentiation of fibroblasts into bone-forming cells (osteoblasts).

odema of CT proceeds to tissue with foci of calcification and then to maturation of calcification and ossifications

Question 32

What is the macroscopic appearance and complications of benign prostate hyperplasia?

Answer 32

macroscopic = noncancerous increase in size

complications = urethra obstruction, urinary tract infections, bladder stones, and chronic kidney disease

Question 33

What is the presentation, appearance and pathophysiology of psoriasis?

Answer 33

presentation = itchy red patches with white scales on top, pus

microscopic = immune cells

macroscopic = red, scaly

pathophysiology = autoimmune triggered by environmental factors