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MBChB Glasgow Year 1 Phase 1 > PBL 4 > Flashcards

PBL 4 Flashcards

1
Q

How are X-rays produced?

A

They are produced when beam of X-rays are passed through the human body and detected by photographic film

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2
Q

How can tissues be differentiated amongst on an X-ray?

A

The tissues absorb different amounts of radiation

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3
Q

What colours will tissues appear on X-rays?

A 
Gas-black
Fat-dark grey
soft tissues (except fat) - grey
Bone - white
Metal objects - bright white
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4
Q

What are X-rays good for?

A
  • Bone fractures breaks
  • Tooth/dental problems
  • Scoliosis
  • Tumours
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5
Q

What are ultrasounds?

A

They produce pictures of the inside of the body using high frequency sound waves

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6
Q

How do ultrasounds work?

A

High frequency sound waves travel through the body and bounce off structures back to a transducer which uses these to form a picture

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7
Q

What are the benefits of ultrasounds?

A
  • They don’t use ionizing radiation

- Images are in real time so can show movement of organs and blood in vessels

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8
Q

What is a colour doppler?

A

Uses a computer to convert the scan into an array of colours to show the speed and direction of blood flow

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9
Q

What is a power doppler?

A

Provides greater detail of blood flow but not direction

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10
Q

What is a spectral doppler?

A

Shows blood flow in graphs with distance and time

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11
Q

What are the functions of ultrasounds?

A
  • Viewing organs
  • evaluating pain causes
  • viewing babies in pregnant women
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12
Q

How are MRIs produced?

A

A strong magnetic field forces the protons in the body to align with that field. A radiofrequent current is the then pulsed through the body causing the protons to push against the field. This current is then turned off and the protons realign with the field and the energy released is detected by sensors in the machine

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13
Q

What is contrast dye used for?

A

To produce a clearer/brighter image

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14
Q

What are MRIs used for?

A

Soft-tissue/non-bony parts of the body.They are particularly useful for muscles, ligaments and tendons

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15
Q

How do MRIs differ from CTs?

A

They don’t use ionizing radiation

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16
Q

How are CTs taken?

A

Using X-rays that move around the body taking cross sections

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17
Q

When would CTs most commonly be used?

A

CTs are one of the fastest and most accurate tools for examining the chest,abdomen and pelvis. For this reason they are likely to be used in trauma situations like MVCs

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18
Q

What are PET scans?

A

They use radioactive tracers to show how well organs and tissues are functioning

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19
Q

How do PET scans work?

A

The build up of the radiotracer (and where it doesn’t build up) is analysed to work out if there are any abnormalities

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20
Q

What are the functions of PET scans?

A
  • detect cancer
  • determine if cancer has spread
  • Determine blood flow to organs and tissues
  • determine effects of heart attacks
  • map normal brain and heart function
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21
Q

What are the two major stages of the cell cycle?

A

Interphase and m phase (mitosis)

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22
Q

What is the cell cycle?

A

The interval between two mitotic divisions?

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23
Q

What happens during S phase?

A

When the DNA is replicated in the nucleus.

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24
Q

What is the purpose of G1 and G2 on each side of the s phase?

A

Time to allow for cell growth before and after DNA synthesis

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25
Q

What can happen at G1?

A

The cell either enters the S phase or G0

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26
Q

What is G0?

A

A resting state where it can remain for days, months or years before re-entering the cell cycle

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27
Q

What happens during m phase?

A

chromosomes and cytoplasm are separated into two daughter cells

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28
Q

What are the distinct phases of M phase?

A

Prophase, metaphase, anaphase, telophase and then cytokinesis

29
Q

What happens in prophase?

A

Beginning at the emd of G2, the chromosomes begin to condense and form an array of loops. The duplicated centrosomes separate and form the poles of the mitotic spindle

30
Q

What is prometaphase?

A

Before metaphase the nuclear envelope breaks down and chromosomes begin to attach randomly to microtubules that come from the two sides of the forming mitotic spindle

31
Q

When is the cell considered to be in metaphase?

A

When all chromosomes are properly attached and lined up in their pairs across the equator of the cell

32
Q

What happens in anaphase?

A

This is where the exit from metaphase begins. The chromosomes separate abruptly

33
Q

What happens in telophase?

A

A contractile ring of actin and myosin assembles as a circumferential belt and constricts the equator of the cell

34
Q

What is cytokinesis?

A

The separation of the two daughter cells

35
Q

How is progression of the cell cycle regulated?

A

Control networks and checkpoints

36
Q

What is the restriction point?

A

a control network that determines if conditions are favourable from the cell cycle to proceed

37
Q

What happens at the restriction point?

A

The cell irreversibly commits to the cell division process

38
Q

What is checked for at the G1 checkpoint?

A

Appropriate energy reserves and size. If it doesn’t have these things it will enter G0

39
Q

What is checked for at the G2 checkpoint?

A

That all chromosomes have been accurately replicated without mistakes or damage

40
Q

What happens at G2 if problems are detected?

A

The cell cycle is halted and the cell will either fix the problem or destroy this cell

41
Q

When does the M checkpoint occur?

A

near the end of the metaphase stage of mitosis

42
Q

What is checked for at the m checkpoint?

A

If the chromatids are correctly attached to the spindle microtubules.

43
Q

What happens if a cell fails the m checkpoint?

A

The cell cycle will not proceed until this check point is completed because the separation of sister chromatids is an irreversible step

44
Q

When do tumours occur?

A

When cell proliferation goes ahead unregulated/uncontrolled

45
Q

What (except CdK-cyclin complexes) control the progression and completion of the cell cycle?

A

Limiting mitogenic growth factors

regulatory genes

46
Q

How does limiting mitogenic growth factors control the cell cycle?

A

growth factors such as platelet-derived growth factor (PDGF) and fibroblast growth factor (FGF) are limited

47
Q

How do regulatory genes control the cell cycle?

A

Regulatory genes actively supress proliferation. These genes, called suppressor genes, control normal cell proliferation.

48
Q

How does Rb show activity of suppressor genes?

A

Each cell has duplicate copies of the retinoblastoma gene as a safety back up. When both copies are mutated, an abnormal Rb protein induces cancerous growth of the retinal cells

49
Q

How do teratomas arise?

A

When germ cells lodge in extragonadal sites

50
Q

What are germ cells?

A

a cell containing half the number of chromosomes of a somatic cell and able to unite with one from the opposite sex to form a new individual; a gamete.

51
Q

what are teratomas?

A

Bizarre growths that contain many different types of tissue such as skin, hair, cartilage and even teeth.

52
Q

Are teratomas malignant or benign?

A

they can be either

53
Q

What stages must cells go through in order to metastasize?

A
  • They have to be able to break away from the original tumour and enter either the blood or lymph
  • They need to be able to attach to the wall of a blood/lymph vessel and move through it to a new organ
  • they must be able to grow and thrive in their new location
  • they need to be able to avoid attacks from the body’s immune system
54
Q

What are proto-oncogenes?

A

Genes that normally help cells to grow

55
Q

What happens when a proto-oncogene mutates?

A

It becomes a bad gene that can become permanently turned on or activated when it’s not supposed to be

56
Q

What can happen when proto-oncogenes go ‘bad’?

A

Cells grow out of control and can lead to cancer

57
Q

What is an oncogene?

A

The ‘bad’, permanently activated proto-oncogene.

58
Q

What is the ‘bad’, permanently activated proto-oncogene now known as?

A

An Oncogene

59
Q

How do most cancer causing oncogenes occur?

A

They are mainly acquired rather than inherited

60
Q

What are oncogenes usually activated by?

A
  • Chromosome rearrangements

- Gene duplication

61
Q

How do chromosome rearrangements cause the activation of oncogenes?

A

Changes in chromosomes that put one gene next to another which allows one gene to activate the other

62
Q

How does gene duplication cause the activation of oncogenes?

A

Having extra copies of a gene can lead to it making too many copies of a certain protein

63
Q

What gene abnormality us found in more that half of human cancers?

A

The TP53 gene - codes for the protein p53

64
Q

What is Intraepithelial neoplasia?

A

New growth within the epilelium

65
Q

What is meant by a benign tumour?

A

The tumour does not invade nearby tissues but can be serious if it is pressing on vital structures like blood vessels, nerves or organs

66
Q

What is meant by a malignant tumour?

A

They are cancerous and can metastasize. The hae a fast growth rate.

67
Q

What is metastasis?

A

When a tumour spreads to nearby tissues

68
Q

Why do malignant tumours stop differentiating?

A

because they proliferate so fast, they also dont receive the signal to switch from proliferation to differentiation

69
Q

Which type of tumour has the bigger chance of relapse?

A

malignant

MBChB Glasgow Year 1 Phase 1 (10 decks)

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