cancer

Question 1

define tumour

Answer 1

a swelling in an organism that is made up of cells that continue to divide in an abnormal way

Question 2

compare benign and malignant tumours

Answer 2

benign:
- grow relatively slowly
- can grow to a large size
- cells usually show normal specialisation
- have a regular looking nucleus
- dont usually spread/stay in one location because produce adhesion molecules and surrounded by capsule

malignant:
- grow rapidly
- can become large
- cells lose any differentiaion or specialisation of original cells
- nucleus of malignant cells can be larger and darker
- doesnt produce adhesion molecules
- not surrounded by capsule

Question 3

why do benign tumours usually stay in one location?

Answer 3

• because cells in benign tumour produce adhesion molecules
• adhesion molecules cause cells to stick together
• benign tumours are often surrounded by capsule of tissue which keeps the cells in one place

Question 4

why might a benign tumour be dangerous?

Answer 4

• by constantly growing, a benign tumour can damage the tissue around it
• if a benign tumour grows on or in an organ it can prevent that organ from functioning normally

Question 5

how are benign tumours treated?

Answer 5

because they are localised, a benign tumour will often be remoed surgically via an operation
- once a benign tumour has been removed it generally wont grow again

Question 6

why is the nucleus of malignant cells larger and darker?

Answer 6

because malignant cells contain more DNA than normal cells

Question 7

what is a consequence of malignant tumours not being surrounded by a capsule?

Answer 7

• malignant tumours can extend growths outwards into nearby tissue
• forming secondary tumours

Question 8

what is a consequence of malignant tumours not producing adhesion cells?

Answer 8

• cells can break away from primary malignant tumour and spread to different locations (metastasis)

Question 9

describe the process of metastasis

Answer 9

• as a tumour develops, blood vessels and lymph vessels can grow into the tumour
• cancer cells can then detach from the primary malignant tumour, and squeeze into these vessels and travel around the body
• the cancer cells can then pass out of the bloodstream and form a secondary tumour at a distant location

Question 10

why is metastasis so dangerous

Answer 10

• secondary tumours can develop at multiple locations all over the body
• so multiple sites of healthy tissue can be destroyed
  -this is likley to be life threatening
• tumours release chemicals which have systemic effects e.g. fatigue and weightloss

Question 11

how are malignant tumours treated?

Answer 11

• can be removed surgically
• if large number of secondary tumours, surgical removal may not be possible
• so chemotherapy or radiotherapy used

Question 12

why else might chemo/radio therapy be used with malignant tumours

Answer 12

some secondary tumours may be too small to detect

and if there is too many secondary tumours

Question 13

compare how chemotherapy vs radiotherapy works

Answer 13

chemotherapy:
- toxic chemicals are used to kill cancer cells
(healthy cells can also be killed)
radiotherapy:
- cancer cells are killed by targeted radiation
(healthy cells can also be killed)

Question 14

why might radio/chemo therapy treatments not work

Answer 14

• because malignant cells spread all over body
• it is possible malignant tumours can reoccur even after treatement