Disorders of tissue growth

Question 1

Normal cells can be classed as labile, stable or permanent. What do these mean? Give an example of each

Answer 1

Labile - constant division, e.g. epithelia
Stable - quiescent, low levels of replication e.g. hepatocytes
Permanent - non-dividing, cannot undergo mitosis e.g. neutrons, myocardiocytes

Question 2

What is the name of stem cell replication? What is this?

Answer 2

Asymmetrical replication

Stem cells divide into one cell that is original to the original stem cell, and one that is differentiated

Question 3

Describe the potency of embryonic stem cells and adult stem cells

Answer 3

Embryo - totipotent (any cell including placenta)

Adult stem cells - pluripotent (any cell excluding placenta)

Question 4

What is agenesis?

Answer 4

Absence of organ or body part -no primordium (tissue a earliest recognisable development stage)

Question 5

What is aplasia?

Answer 5

Failure of organ to develop (can have primordium or be rudimentary organ)

Question 6

What is hypoplasia? What can cause this?

Answer 6

Failure of an organ to develop to full size

Genetics, hormones, deficiencies, infectious agents

Question 7

What is atrophy?

Answer 7

shrinkage of organ/tissue after grown to full size

Reduce in cell size (qualitative) or number (quantitative)

Question 8

What is the difference in aplasia and agenesis?

Answer 8

Agenesis - no primordium

Aplasia - primordium or rudimentary organ

Question 9

What is the difference between hypoplasia and atrophy?

Answer 9

Hypoplasia - organ doesn’t ever reach full size

Atrophy - organ reaches full size then shrinks

Question 10

What are different types of metaplasia?

Answer 10

Squamous - from columnar to squamous epithelium

Mesenchymal - from fibrous tissue to cartilage or bone

Question 11

What is dysplasia?

Answer 11

Loss of uniformity and orientation of cells

Question 12

Is dysplasia reversible? What can cause it?

Answer 12

Yes

Chronic inflammation

Question 13

What happens if the injurious stimulus that causes dysplasia persists?

Answer 13

Becomes neoplastic

Question 14

What is anaplasia?

Answer 14

Resemblance to embryonic form of tissue - lack of differentiation. Type of neoplasia

Question 15

What is neoplasia? How does growth compare to normal tissue?

Answer 15

New growth - forms abnormal mass of tissue

Growth uncoordinated and faster than normal tissue

Question 16

What is a tumour/oncos?

Answer 16

Swelling caused by neoplasia

Question 17

Neoplasia can be malignant or benign. What is malignant tumour? What does it do?

Answer 17

Cancer
Invades and destroys adjacent tissues
Metastasises to cause death

Question 18

How do benign neoplasia differ from malignant neoplasia?

Answer 18

Remain localised
Don’t spread
Can be surgically removed (generally)

Question 19

Neoplasms are monoclonal proliferations. What does this mean?

Answer 19

All neoplasms are clones from one mutated cell

Question 20

What are the general rules of neoplasia (3 - there are exceptions)?

Answer 20

Growth is not reversible
Caused by changes in DNA
Tumours are non-transmissable diseases

Question 21

Epithelial tumours are of endodermal/ectodermal origin. How are they named?

Answer 21

Benign - end in oma

Malignant - end in carcinoma

Question 22

Mesenchymal tumours are of mesodermal origin. How are they named?

Answer 22

Benign - end in oma

Malignant - end in sarcoma

Question 23

How are leukaemia (liquid tumours named)?

Answer 23

Acute or chronic + cell of origin + leukaemia

Question 24

Where do teratomas arise from? Where are they often found?

Answer 24

Arise from germ cells composed of tissues from all embryonic layers
Contain several different types of tissue
Ovaries, testes

Question 25

What are hamartomas?

Answer 25

Abnormal mixture of tissues in a place where growth occurs (normal location) Growth abnormality, soon after birth

Question 26

What are choristomas?

Answer 26

Abnormal mixture of cells in an ectopic location | Growth abnormality, soon after birth

Question 27

How do benign and malignant tumours vary in terms of differentiation?

Answer 27

Benign - well differentiated | Malignant - go between well-differentiated and anaplastic (not differentiated)

Question 28

How do malignant tumours and benign tumours vary in terms of local invasion?

Answer 28

Benign - remain local, expansile growth | Malignant - infiltrate and destroy surrounding tissues, infiltrative growth

Question 29

Stroma (connective tissue) is produced by epithelial and malignant tumours. How do they differ in stroma production?

Answer 29

Epithelial tumours - stroma produced by surrounding, non-neoplastic mesenchymal cells Mesenchymal tumours - produce their own stroma

Question 30

How does tumour stroma growth relate to tissue growth?

Answer 30

As tumour increases, stroma production increases

Question 31

What do tumours do to ensure they can continue growing? What would happen if this didn't happen?

Answer 31

Angiogenesis - enables blood supply | If no blood supply - necrosis

Question 32

How do tumour blood vessels differ to normal blood vessels?

Answer 32

Tumour vessels more dilated, tortuous and permeable

Question 33

Why is haemorrhage a common problem with tumours?

Answer 33

Tumours cause angiogenesis - blood vessels often imperfect so haemorrhage

Question 34

What is metastasis? What vessels does this happen via?

Answer 34

Transmission of cancerous cells from one site to another on the body Blood or lymph vessels

Question 35

What is a complication of metastasis? What may this lead to?

Answer 35

Tumour embolism - blockage of vessel | Causes infarction and oedema

Question 36

What do tumours form to evade the immune system?

Answer 36

Homotypic or heterotypic clusters

Question 37

Describe the stages that cause a tumour to metastasise

Answer 37

Intravasation Tumours evade immune system Extravasation Extravascular tumour creates suitable environment - e.g. neovascularisation

Question 38

What is intravasation? How does this happen?

Answer 38

Invasion of cancer cells into vessel | Due to increased permeability or digestion of basement membrane

Question 39

What is extravasation? What may tumour cells have to help this occur?

Answer 39

Movement of cancerous cells out of vessel and into tissue | Adhesion molecules