Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Fun-physics > L.3 > Flashcards

L.3 Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

What is electromagnetic radiation (e-m)?

A
  • an interaction between the changing electric and magnetic fields associated w the movements of charged particles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does the e-m spectrum show?

A

The different types of e-m radiation that exists

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Draw a clearly labeled diagram showing all the main components of the electrons magnetic spectrum and states the typical values of frequency or wavelength for each of these.

A

(Practice drawing)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the only difference in the various bands of radiation?

A
  • they are all identical in nature in how they’re generated.
  • The only difference is the wavelength or frequency of the radiation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Do all e-m radiation travel at the same speed? If so what is it!

A
  • yes they all travel in the same speed
  • they travel in the speed of light (3x10^8 m/s)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the relationship of e-m radiation?

A

V wave = f • n
(Velocity = frequency x wavelength)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does e-m radiation consist of?

A

Photons - and photon energy is directly proportional to the frequency of the wave

E a f

This is why gamma rays are more energetic than radio waves and blue light contains more energy per photon than red light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Ionizing radiation Vs non ionizing radiation?

A

Ionizing radiation (10^ 16 and 18)
- bonds break
Non ionizing radiation (10^ 6,8,10,12,14)
- heating

Radiation w a frequency > 1 • 10^15 Hz will actually break Honda and cause e- to be freed from an atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

For biological tissue, what wavelength or photon energy will cause the breakage of bonds and electrons to be freed from an atom?

A
  • wavelengths less than ~300 nm (UV)
  • photon energies greater than ~ 4 eV
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the uses for e-m radiation in medicine or physiotherapy?

A
  • short wave therapy (diathermy)
  • microwave diathermy
  • x rays
  • gamma rays
  • visible radiation
  • blue/violet radiation
  • UV radiation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is short wave therapy, what does it do, and what frequency range does it use?

A
  • is gentle heating - a non superficial heat treatment in patients
  • provides heat to release pain, increase mobilization, and improve blood flow
  • uses frequency range 10-100 MHz but the typical value is 27.12 MHz
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How is short wave diathermy (SWD) passed to a patient l?

A
  • via electrodes
  • the electrical and magnetic fields associated with the e-m radiation causes the charged molecules within the tissue to vibrate and hence the kinetic energy is converted to heat.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What kinds of tissues are usually good conductors and respond well to SWD?

A
  • tissues which contain a high number of free ions (muscle tissue, blood, etc)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What must you beware of when using SWD?

A
  • hazards as metal and sweat also respond well to SWD
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What types of heating can SWD produce?

A
  • produces both superficial or deep tissue heating (the heating is a direct result of joule heating, E= 1^2Rt)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

SWD has been observed to…?

A
  • increase blood flow
  • help reduce inflammation
  • increase the extensibility of deep collagen tissues
  • decrease joint stiffness
  • relive deep muscle pain and spasm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does microwave diathermy work?

A
  • water molecules in tissue absorb the microwave energy
  • vibrational energy converted to heat
  • frequencies used are ~2450 MHz
  • provides deep penetration into tissue
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What caution is required when utilizing microwave diathermy?

A
  • caution is required not to cause bone burns
19
Q

What are x rays used for?

A
  • X-rays can be used to examine most areas of the body. They’re mainly used to look at the bones and joints, although they’re sometimes used to detect problems affecting soft tissue, such as internal organs. Problems that may be detected during an X-ray include: bone fractures and breaks.
20
Q

What are gamma rays?

A
  • Gamma rays are a form of electromagnetic radiation, as are radio waves, infrared radiation, ultraviolet radiation, X-rays and microwaves. Gamma rays can be used to treat cancer, and gamma-ray bursts are studied by astronomers.
21
Q

Ways to view visible radiation?

A
  • eye - simple lol at your patient
  • fibre-optic endoscopes
  • opthalmascope
  • otoscope
22
Q

What does the white light used in endoscopy contain?

A
  • infrared (IR) radiation (basically heat) and it is therefore desirable to use IR filters to absorb this and minimize unwanted heating of healthy tissue (cold light endoscopy)
23
Q

What regions can be investigated using endoscopes?

A
  • esophagus
  • stomach
  • biliary tree
  • duodenum
  • small intestine
    a colon
  • appendix
  • sigmoid flexors
  • text um
  • liver (?)
24
Q

What is transillumination?

A
  • refers to the transmission of light (usually visible) into various parts of the body for the purpose of diagnosis
25
Q

Why is red glow often associated with transillumination?

A
  • red light will further penetrate into tissue and undergo scattering while blue light is more easily absorbed at the tissue surface
26
Q

What can transillumination be used for in infants? Explain.

A
  • used effectively to detect hydrocephalus in infants
  • since the skull is not fully calcified in infants, visible light penetrates quite easily. If there is an excess of CSF light will be scattered to different parts of the skull producing a characteristic pattern.
27
Q

What other things other than detecting hydrocephalus can transillumination be used for?

A
  • diagnose pneumothorax
  • studying problems with the gums
  • sinus cavities and breasts
28
Q

What are visible lasers - photodynamic therapy (PDT) do or used for ?

A
  • a photosensitive drug is administered to the patient and after some period of time, it will be selectively taken up by cancerous cells. When the cancerous area is exposed to light of a certain wavelength, singlet oxygen is produced which is extremely toxic to the cancer cells.
  • Once the photo sensitive drug (usually a porphyrin derivative) has been taken up by the cancer cells, the extent of the lesion may be observed using fluorescence
29
Q

What does fluorescence image show?

A
  • The clear boundaries of a skin lesion which cannot be seen with the naked eye.
30
Q

Where do most clinically useful lasers operate?

A
  • the visible part of the spectrum
31
Q

How can UV/Blue light radiation help infants?

A
  • Infant suffering from jaundice (excess bilirubin excretion from the liver) respond very well to exposure from the RUV/blue light
  • Broadband light centred on approximately 450 nm seem to produce the best effect when the infant is exposed to the lamp source for a period of 12 to 24 hours
32
Q

What has a higher frequency than visible or red light?

A
  • UV light has a higher frequency than visible or red light, and therefore has greater energy per photon
  • this is useful but also rlly harmful 
33
Q

What can UV light convert and effect?

A
  • UV light can also convert molecular products in the skin to produce vitamin D, which can improve skin conditions such as psoriasis
  • UV radiation also affects melanin in the skin to cause tanning. However, excessive exposure may burn and can be avoided by sunblock etc.
  • However, these wavelengths are also well absorbed by DNA cells in the skin and prolonged exposure can lead to the formation of skin cancers such as basil cell carcinoma (BCC) and squamous cell carcinoma (SCC)
34
Q

UV light with wavelength < 300 nm is?

A
  • germicidal
35
Q

Why can’t we see UV light?

A
  • UV light is very easily absorbed in the surface tissues over eyes and never gets through the lens at the front of the eye.
36
Q

What can excess absorption of UV light by the lens result in?

A

Cataracts

37
Q

What happens when the lens of the eye is removed?

A
  • People who have had the lens removed because of excess cataract formation can often see into the UV part of the spectrum since the primary absorber of UV - the lens - has been removed
38
Q

In the form of what do more than half of the energy reaching the earth from the sun?

A
  • infrared radiation - heat (IR)
39
Q

Is IR radiation much more penetrating than UV light? What will this mean?

A
  • yes
  • hence will penetrate through the lens & be focused onto the retina - could be hazardous in the form of a retinal burn.
40
Q

What are the benefits of therapeutic heat lamps?

A
  • it produces a high % of high intensity near IR radiation (wavelength ~ 1000-2000 nm)
  • can be used to deep heat tissues
  • increased metabolism results in a relaxation of the capillary system (vasodilation).
  • increase blood flow in the region of treatment
  • excellent treatment for muscular and soft tissue injuries
41
Q

Thermography - what is it & what can it be used for?

A

All objects with a temperature greater than absolute 0 Willamette radiation, and the wavelength of light radiation is inversely proportional to the objects temperature.

42
Q

What is wines law?

A
  • wavelength a 1/T
43
Q

What wavelengths do we emit?

A
  • the amount of IR emitted by the body (W) is determined primarily by the temperature of the body

W= eAoT^4

Where e is the emissivity, A is the area of the body, and o is the Stefan-Boltzmann constant

Since the IR intensity is proportional to T4 if we can map or measure the IR intensity as a function of position, this gives a very good map of surface temperature. Such a technique is called thermography

44
Q

What can we use thermography be used for?

A
  • Since blood flows is an efficient means of heat transport within the body, thermography can give a good indication of surface blood distribution although there are mixed views and it’s gonna go usefulness nowadays
  • It has been used as a good first indicator of tumours in breast cancer patients, as well as identifying areas of reduced blood flow in patients with diabetes or vascular problems

Fun-physics (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions