Transcript Medical Laboratory Technics - Zoology For You : HS level

MEDICAL LAB TECHNIQUES
MEDICAL LABORATORY TECHNIQUES
Use of medical laboratory instruments for the diagnosis of
diseases and infection of a person for and treatment
are called medical lab techniques
 CT scan
 Stethoscope
 Haemocytometer
 Sphygmomanometer
 Electro Cardio Graph
Stethoscope:
types
Binatural stethoscope
Electronic stethoscope
Stethoscope:
Uses
Helps to find normal (lub_dub) sound and abnormal heart sound
Indicates fluid in lungs in case of pneumonia and pulmonary edema:
bronchitis, pleuritis
compare the movements in normal and over or under active intestinal tract
SPHYGMOMANOMETER
TYPES
It is an instrument used to measure
the blood pressure of an individual
monometric sphygmomanometer
digtal sphygmomanometer
Uses
• It helps to estimate the state of blood
circulation and working of heart.
• It helps to diagnose pathological conditions such
as hypertension (increased blood pressure) and
hypotension (decreased blood pressure)
SPHYGMOMANOMETER
It consist of a mercury manometer cuff and hand pump.
The cuff is tied around the cubital fossa of the individual,
Then hand pump is pressed.
Air is inflated in the cuff.
When the cuff is fully inflated air pressure is more than
blood pressure,
So blood flow is obstructed
USES OF SPHYGMOMANOMETER
Now the hand pump is slowly released till the time the
appearance of the first sound.
The manometric reading is noted. Systolic pressure
Later the hand pump is slowly released till the time of the
sound becomes louder.
Later it stops the manometric reading is noted when the
sound disappears_ diastolic pressure .
BLOOD PRESSURE
• It is the force of pressure which the blood is exerting on the
walls of blood vessels.
• SYSTOLE:Contraction of left ventricle --Pressure rises to a
peak-Systolic pressure.
• DIASTOLE:relaxation of left ventricle -Pressure falls-Diastolic
pressure
• The normal blood pressure value is 120/80.
HAEMOCYTOMETER
A device used for determining the number of cells per unit
volume of a suspension is called a counting chamber.
The most widely used type of chamber is called a
hemocytometer, since it was originally designed for
performing blood cell counts.
A haemocytometer consists of a counting chamber, a
coverglass for the counting chamber and diluting pipettes.
many types of counting chambers are available.
improved neubauer and fauchs rosenthal are the 2 most
commonly used counting chambers.
HAEMOCYTOMETER:
Method of Using
To prepare the counting chamber the mirror-like polished
surface is carefully cleaned with lens paper.
The coverslip is also cleaned. Coverslips must be heavy
enough to overcome the surface tension of a drop of liquid.
The coverslip is placed over the counting surface prior to
putting on the cell suspension.
The suspension is introduced into one of the V-shaped
wells with a pasteur or other type of pipette.
R.B.C. PIPPETTE
W.B.C.
PIPPETTE
HAEMOCYTOMETER:
Method of Using
The area under the cover slip fills by capillary action.
Enough liquid should be introduced
so that the mirrored surface is just covered.
The charged counting chamber is then placed on the microscope stage
and the counting grid is brought into focus at low power.
Cell suspensions should be dilute enough so that the cells do not overlap
each other on the grid, and should be uniformly distributed.
To perform the count, determine the magnification needed to
recognize the desired cell type.
Now systematically count the cells in selected squares so that the total
count is 100 cells or so
HAEMOCYTOMETER:
Method of Using
To get the final count in cells/ml, first divide the total count by 0.1
(chamber depth) then divide the result by the total surface area
counted
.
For example if you counted 125 cells in each of the four large corner
squares plus the middle, divide 125 by 0.1, then divide the result by 5
mm-squared, which is the total area counted (each large square is 1
mm-squared). 125/ 0.1 = 1250. 1250/5 = 250 cells/mm-cubed.
RED BLOOD CELL COUNT
Normal range of RBC in human
• Men • Women • At birth –
4.5 - 5.9 million /cu /mm
4.1 - 5.1 million /cu /mm
4.0 - 5.6 million /cu /mm
WHITE BLOOD CELL COUNT
Normal range of WBCs in human
Adult: 4.500-11.000/cu.mm
Neonates:10,000-25,000/cu,mm.
HAEMOCYTOMETER: Clinical significance
Decrease in the number of circulating RBC indicates
Anaemia.
An increased in the number of RBC indicates
Polycythemia.
An increase in WBC for a transient period indicates
Bacterial infection.
Progressive increase in abnormal WBC count indicates
Leukemia.
Electrocardiogram
It is an instrument used to record the electric potential
changes that occur in the heart during cardiac cycle.
Recording of ECG with a strong galvanometer was done by
Einthoven.
Waller was the first to record human ECG with a capillary
electrometer.
Einthoven was awarded Nobel Prize in 1924
ELECTROCARDIOGRAPH
It is a record of the electric potential changes of the heart
imprinted on a strip of paper in the form of waves
Some amount of this current spread to the body surface.
The electric potentials generated by this current can be
recorded by placing electrodes on the opposite sides of the
heart.
The waves of ECG are formed due to depolarization of
heart muscles.
They are not formed due to contraction of the heart.
P wave
It is an atrial wave.
Caused due to spread of depolarization in the atria.
Duration :0.1Sec. Amplitude: 0.1 to 0.3 Sec.
P,R,and T waves
Positive waves-Upward waves
Q and S waves
Negative waves-Downward waves
Q,R and S waves
It Generally referred as QRS complex.
Q-wave
It is a small negative downward deflection.
represents the atrial septal depolarization.
R-wave
It is a prominent positive
S-wave
It is a small negative
R and S waves
formed due to the depolarization of ventricular muscles.
T wave
It is a broad wave.
It is due to the ventricular repolarization.
Duration : 0.27 Sec.
Amplitude : 0.15 to 0.5 mv.
COMPUTED AXIAL TOMOGRAPHY
CT or CAT
- is a non invasive diagnostic technique
- provides a clear view of soft internal organs & tissues.
- this technique uses a type of X-ray device.
HISTORY OF CT
. was invented in 1972 by British engineer Godfrey
1) CT
Hounsfield England .
2) It was independently invented by South A frican born physicist
Allan Cormack, Massachusetts.
3) The first clinical CT scanners were installed between 1974 and
1976.
4) CT became available by about 1980
COMPUTED TOMOGRAPHY SCAN or CT SCAN
CAT Scanning is the computer analysis of a sharply limited, thin X-ray beam
passed through an area of the body.
X-ray signal received is converted to binary data which is read by the
computer electronically.
X-rays which pass through the body are absorbed at different levels, CT is
based on X- ray principle.
These rays create a matrix or profile of X ray beams of different strength.
This X ray profile is registered on film, thus creating an image.
In CT, the film is replaced by a banana shaped detector, which measures the
X ray profile.
USES OF CT
CT is an invaluable tool in the cancer diagnosis process and
is often the preferred method for diagnosing lung,liver and
pancreas cancer.
CT imaging and CT angiography are finding a greater role in
the detection, diagnosing and treatment of heart diseases
acute stroke and vascular diseases.
CT can be used to measure bone mineral density for the
detection of osteoporosis.
CT has excellent application in trauma cases and other
internal bleeding in patients.
CT is used extensively for diagnosing problems of inner ears
and sinuses.
CT is excellent for imaging tumours or polyps in the sinuses.
USES OF CT continued
CT has been the basis for interventional work like CT guided
biopsy and minimally invasive therapy
CT images are
. also used as basis for planning radiotherapy
cancer treatment.
CT is often used to follow the course of cancer treatment to
determine how the tumour is responding to treatment.
ADVANTAGES OF CT OVER OTHER TECHNIQUES
Conventional X- ray can show only the dense bone structure
of the skull.
 X-ray angiography of the head shows only the head and
neck and not the soft tissue of the brain.
 Magnetic resonance shows only the soft tissue and not the
bony skull.
 But CT allows physicians to see soft tissues,anatomy of
brain ventricles,of grey and white matter.
End