For 2nd Year Chemistry and Biochemistry

1. By
Dr GALAL ZEDAN FARAG
TANTA UNIVERSITY
FACULTY OF SCIENCE
PHYSICS DEPARTEMENT

6. Fig(1) . First, second and third class levers.

9. Fig (3 ), (a) cell in hypertonic solution
(b) cell in hypotonic solution.

13. Figure 7: A graphical representation of the
concentrations of particles as a func¬tion of x for
different times when the initial concentration (at t=0)
is that all the particles are at the origin,

14. Figure. (8) : Schematic representation
of one model of a pore in a plasma
membrane. The membrane is
depicted here in cross section.

15. Fig. (1) Plasma membrane
Figure (2): Nerve cell
Figure 9: A. schema tie representing of an axon
in the resting state. The dipole sheath across the plasma
membrane, positive outside and negative inside, produces
a difference in potential of about 90 mV across the plasma
membrane.

17. Fig.(4): Action potential propagation in a mylinated nerve.

18. Fig. (5): Action potential of a nerve.

20. External and middle ear, opened from the front; right side.

21. View of the inner wall of the
tympanum (enlarged)
The right membrana tympani with the hammer and the chorda tympani, viewed from
within, from behind, and from above

29. Light and Vision

32. The accommodation process
Because lens is a liquid crystal much like jelly:
, its shape can be changed by the tension excreted by the ciliary muscles. This tension is in
turn controlled by a nervous signal fed back from the retina, the cells of which estimate the
sharpness of the image.
PHOTOSENSITIVE CELLS:
rod cone
scotopic vision
more sensitive to light, and distinguish for us
light from dark view the intensity is very low
(twilight vision)
less sensitive can resolve large amounts of
light into its components, and therefore
detect details of the image, such as shape
and color
photonic vision
126,000 cells/mm2
the fovea
red (6200 to 7800°A),
green (5000 to 5800°A)
blue (4200 to 5000°A);
mix color

33. Figure 27
The scheme above indicates that:
• the greater the intensity of the incoming light, the more will the rhodopsin be reached.
• In twilight most of the pigment exists as rhodopsin, and the sensitivity is greatest.
• In daylight, most of it will be bleached, and the sensitivity least.
• "Dark-adaptation" is very familiar to us all; it is slow because the speed of regeneration
of rhodopsin is slow.

34. CHAPTER VII
X-RAYS
(i)- Types of waves:
A wave is the form by which energy is transferee from one point to the other. There are only 2
types of waves which are :
A- Mechanical waves

35. B-Electromagnetic waves (e.m.w):
(ii)- The electromagnetic spectrum :
One Angstrom = 1A=10-10 mm=10-8m
= 10-4u(micron)=10 nm (nanometer).
(iii) Unite
a-The Rontgen: is the amount of X-
rays or gamma radiations which
produces ions carrying a charge equals
3×10-10 coulombs in 1 cm3 of air. This
unit is used as a measure of exposure
to the radiation in air.

36. b-The Rad (Radiation absorbed dose):
is the amount of absorbed energy which equals 100 ergs (10 joules) per gram of
any absorbing material. The rad equals 103 milli-rad. Recently, a new unit called
the Gray is used, where 1 Gy = l joules/k gm. (1 rad = 0.01 Gy = 0.01 J/k gm.).
C-The Curie:
is the amount of radioactive material (isotope) which gives 3.7×l010 disintegration/sec.
Recently, a new unit called the Bequrel is used where 1 ci = 37 G Bq. (G = 109 )
e- Intensity:
It equals the energy E per unit area of An absorber per second , I =
𝑬
𝑨 𝒏.𝒕
where t is the time in seconds, and An is the unit area for n material.
d- The electron volt (eV):
is the unit of energy. It equals to the amount of energy which; is gained by an electron
moving between two points having potential difference of 1 volt.
The energy of the electron= the charge of the electron (1.6×10-19 coulomb) × the potential
difference (1 volt) = 1.6×10-19 coulomb × volt = 1.6×10-19 joule
1 eV = 1.6×10-19 joule.

37. 2- X-Ray Production Tube (Coolidge X-ray tube)
X-rays were discovered by William Rontgen in 1895
a) Calculation of the energy of X-ray line
spectrum (𝐾 𝛼, 𝐾 𝐵. .):
𝐵𝐸 𝑛 = −
𝑚𝑒4 𝑧2
8𝑒 𝑜
2ℎ2 .
1
𝑛2 (1)
= constant
1
𝑛2 (2)
K X-rays are emitted when the electron from L
shell (n=2) fills the vacancy in the K shell (n=l). The
energy of these X-rays (EK ) = the difference between
the electron energy in the L shell (En=2) and that of
the K shell (En=1).
Equation 2 gives E2= -constant
𝟏
𝟐 𝟐 =constant(
𝟏
𝟒
) .
E2-E1= - constant (
𝟏
𝟒
−
𝟏
𝟏
) = -constant (−
𝟑
𝟒
)
= -constant ×
𝟑
𝟒

38. Another possibility for these accelerated electrons is that
they do not meet and collide with any electron in the target
atom, but moves near the positive nucleus at distances (X1,
X2, X3, X4, …Xn).
I
X3
X2
X1 E
X-ray continuous spectra (Bremsstrahlung(

39. Bremsstrahlung
I
E
Actual X-ray spectrum (Line & Continuous spectra)
K
K
4- USE Of X-RAYS IN DIAGNOSIS depends on
1-The electron density of the metal i.e. its
absorption coefficient (u)
2-The thickness of the absorbing metal (d)
3-The intensity of the X-ray incident on the
material (Io)
half value layer (h.v.l)
𝒂𝒃𝒔𝒐𝒓𝒃𝒆𝒓 (𝒅 𝟏
𝟐
)
(𝐼𝑜/2).

41. M.V.L. and it is a measure of the degree of penetration of the X-rays or gamma rays
(a) Calibration of the X-ray beam energy emitted from the X-ray tube.
(b) Design of a filter from certain elements of known(u) to reduce the dose intensity and
energy of the X-rays.
(c) Design of protection walls and screens for the personnel operating the X-ray machine.
[less absorbed x-rays]
Absorption of X-rays by atoms of different absorbers. (basis of diagnosis).

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