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VIETNAM NATIONAL UNIVERSITY
HANOI UNIVERSITY OF SCIENCE
FACULTY OF BIOLOGY

EXPERIMENTAL REPORT: HUMAN AND ANIMAL
PHYSIOLOGY

Hanoi - 2021


VIETNAM NATIONAL UNIVERSITY
HANOI UNIVERSITY OF SCIENCE
FACULTY OF BIOLOGY

EXPERIMENTAL REPORT: HUMAN AND ANIMAL
PHYSIOLOGY

Nguyễn Thúy An-19001145-K64 CNSH
Vũ Bá Lê Duy-17000587-K62 CNSH CLC
Nguyễn Thu Hà-19001218-K64 CNSH CLC
Phạm Thị Thu Hà-19001175-K64 CNSH
Phạm Thị Minh Nguyệt-16002372-K61 QTS
Hồ Nguyệt Minh-19001206-K64 CNSH

Hanoi - 2021


TRANSMISSION OF IMPULSES ACROSS NERVES AND SYNAPSES
I. OBJECTIVE
‐
‐

Observe transmission of impulses across nerves and synapses.
Preliminary interpretation of experimental results to better understand the
mechanism of nerve impulses.
II. PRINCIPLE
‐ An action potential or nerve impulse is generated when a nerve or muscle is
stimulated. The impulses are transmitted along nerves and across synapses.
Nerves are capable of bidirectional conduction, but synapses only allow
unidirectional conduction from the presynaptic membrane across the cleft to the
‐

postsynaptic membrane.
Create neuromuscular preparations of frogs and set up an experimental model,

we can observe this phenomenon.
III. MATERIALS
‐ Frog dissection kit.
‐ Surgical tray, medical gauze, Ringer solution
‐ Electric stimulator
IV. PROTOCOL
Step 1: Dissect and create 3 neuromuscular products of frogs
Step 2: Plug in the electrical system to stimulate.
Step 3:
‐ Place 3 neuromuscular preparations on the canvas: the nerve of product 3
crosses the muscle of product 2
‐ The nerve of product 2 crosses the muscle of product 1

Step 4:

‐

Detect threshold and stimulate the nerve of product 1 (in A): muscles of all 3
products contract

‐

If there is an accurate time recorder, it will get the results that the muscle of
product 3 contracts slower than the muscle of product 2, the muscle of product 2
contracts slower than the muscle of product 1.

‐

Thus, the electric current stimulates the nerves product 1, causing excitement,
generating impulses. The impulse is transmitted along the wire, through the
synapse, stimulating the muscle to cause the muscle to contract. When the muscle
of product 1 contracts (excited) produces an action potential, this potential
stimulates the nerve of product 2 and generates a new impulse that travels along
the wire and through the synapse to the muscle of product 2, stimulating I love
muscle contractions.

‐ The same applies to the muscles and nerves of the product 3.
Step 5:
‐ Use a stimulation electrode in the middle of the nerve of product 2 (in B)
‐ The result is that all 3 muscles of the 3 products work together.
Step 6:
‐ Switch the electrical stimulation site to the middle of the nerve of product 3 (at
C).
‐

The result is that only the muscles of product 2 and 3 contract while the muscles
of product 1 do not
V. RESULT AND CONCLUSION
5.1. Result


‐
‐

Stimulation at site A: Muscle bundle 1 contracts, muscle group 2 contracts,
muscle group 3 contracts weakly
Stimulation at site B: Muscle bundle 2 contracts, muscle bundle 1 contracts

‐

Stimulation at site C: Muscle bundle 2 and muscle 3 contract. Muscle bundle 1
does not contract
5.2. Explain
‐ In this experiment, it is not possible to stimulate the muscle bundle by crossing
the nerve on it
‐ Theoretically, when electrical stimulation is applied to a nerve, the impulse will
travel in two directions and cause contraction of two muscles next to that nerve.
At site A, when stimulated, it will cause 3 muscle bundles to contract. At site B,
bundle 1 contracts, bundle 2 contracts theoretically, bundle 3 will contract. Site

‐

C causes bundle 3 to contract, bundle 2 to contract and bundle 1 to not contract
because the electrical signal will not be able to propagate back from the posterior
membrane to the anterior membrane. However, in all three experiments, we see

a difference compared to the theory.
The difference in practice can be explained by the following reasons that at this
time the nerve impulse is obstructed by:


●

The amount of fat in the muscle reduces the intensity of nerve impulses,
making it impossible to reach the threshold to generate action potentials that

‐

●

cause muscle contraction.
The amount of potential is not enough because when the nerve is placed across
the muscle, it only contacts the muscle bundles in that position, and the muscle

●

bundles below have not received the impulse, so they do not contract.
At the same time, at the point of contact of nerves and muscles, there is a layer
of Ringer's physiological solution, which can also be a factor in reducing the

intensity of the pulse.
When stimulating at site A, we see that most of the time, only 2 muscles I and II
contract, even in some cases only muscle I. It can be speculated that the nerve
impulse has been reduced after passing through the nerves. nerves and muscles.

‐

‐

Therefore, it is not possible to reach the threshold to induce muscle stimulation
on the third muscle bundle.
Site B did not show muscle 3 contractions, possibly because the electrical impulse
was obstructed and weakened during transmission.
The reduction in nerve impulses can be explained by the amount of fat in the
muscle, the individual physiological characteristics of each muscle bundle,
whether the impulse conduction or muscle contraction is done well, and the
intensity of the excitation current.


ANALYSIS OF SPINAL REFLEX ARC IN FROG
I.
OBJECTIVE
‐ Calculate the reflex time
‐ Learn the role of component elements in the reflex arc
II. PRINCIPLE
‐ Reflex is the body's response to any form of stimulus from the environment. That
is the principle of operation that covers and runs through each individual's life.
Each reflex must have a corresponding reflex arc. The reflex arc consists of 5
elements:
●
●
●
●
●

Acceptance.
Afferent nerve.

Central nervous system.
Centrifugal nerve.
Implementing agency (or agency)

‐

Later, it was also recognized that a sixth element in the reflex arc is the reverse
radial line from the agency to the center. Reflection is only possible when the
elements of the reflex arc are intact in both structure and function

‐

The time from when the stimulus acts to when the reflex occurs is called the reflex
time or the latent time.

‐

On a frog-marrow preparation, it is possible to measure the time as well as
analyze the components of the reflex arc.
III. MATERIALS
‐ Frog
‐ Frog dissection kit
‐ Operating table, operating tray
‐ Ringer solution.
‐ 1% H2SO4 solution.
‐ Crystal salt NaCl, ether.
‐ Two small beakers for acid, one large beaker for water.
‐ Thread, stopwatch, small and medium scissors, amputee, hanger.
‐ Two glass rods with hooks.
IV. PROTOCOL

Step 1:
‐ Frogs don't poke marrow.


‐

Wrap a frog with a towel and use large scissors to cut across the frog's head below
the eyes.

‐
‐
‐

Hook the lower jaw and hang it on the test stand.
Bleeding in the cut. Let the frog be quiet for a while.
When the frog was quiet, the hind legs were hanging down before starting the

experiment.
Step 2:
‐ Use a small glass cup containing H2SO4 solution, 0.5%, gently lift from the
bottom so that the frog's feet are dipped in the acid but do not touch the wall of
the cup.
‐
‐

When the frog's feet start to touch the acid, press the clock.
When the frog reacts, he lifts his legs and presses the clock. The difference in

‐

time is the reflex time.
Rinse the frog's legs with water several times and wait for the frog to calm
down again.

‐
‐
‐

Repeat the experiment 3 times to get the average time.
Replace with 1% acid solution and do the same as above.
When the frog's legs come into contact with acid and begin to contract, the frog
often squirms and shoots the acid, so be ready to hold the frog and put it in a

cup of water to wash it right away.
Step 3:
‐ After rinsing and letting the frog rest, use scissors to cut a loop of skin near the
knee joint, then peel off the skin from there down to the toes.
‐ Repeat the above experiments on skinned frogs and observe the results,
explaining what happened.
Step 4:
‐ On the opposite leg (with the skin intact), cut the posterior thigh muscle about 3
cm with scissors, and then use two glass hooks to separate the sciatic nerve.
Test the reflex leg contractions with acid in the following cases.
‐ Normal (after separating the nerve, wet the physiological solution, wait for the
frog to be quiet before doing the experiment).
‐ Use a thread to thread under the nerve and tighten (1 knot). After threading, test
reflexes and observe the results.
Step 5:

‐

Using the second frog, peck and separate the sciatic nerve in both thighs. On the
first leg, test the acid reflex.

‐
‐
‐
‐

Then take a cotton pad soaked in ether and place it between the sciatic nerve in
the thigh.
After 5 minutes, test again the leg contraction reflex with acid.
Observe, compare, and interpret results.
On the second leg, test the acid reflex. Then put some salt crystals in the middle
of the sciatic nerve. After about 5 - 10 minutes, test again with the acid reflex.

Observe, compare and interpret results.
Step 6:
‐
‐

Using the third frog, cut off the head and hang it on the rack.
Dissect and separate the sciatic nerve in one leg.

‐

Test the acid reflex, then sever the nerve, and then test the reflex again.
Observe, compare and interpret results.
In the intact leg, test the leg contraction reflex with acid.

‐
‐
‐

The amputee is then poked directly into the spinal cord at the cross-head
incision. Retest the leg contraction reflex with acid.
Observe, compare and interpret results.

V. RESULT AND CONCLUSION
5.1. Experiment 1: Determine the reflex time
‐ Experiment results
1st time: T1 = 1.5 seconds
2nd time: T2 = 2.0 seconds
3rd time: T3 = 2.0 seconds
Average time: (T1+T2+T3) :3 = 1.83s
Explain
‐ After the experiment, the frog's feet must be washed thoroughly because: If the
frog's feet are not washed, a moderate stimulus for a long time will lead to
resistance to stimulation and prolong the reflex time.
‐ The results after 3 experiments showed that there was not too much difference
in the reflex time. In the latter two times, the reflex time is longer than the first
time because it is likely that they have become accustomed to the stimulus.
5.2. Experiment 2: Determine the role of the receptor
Characteristic

Result

Explain

After peeling, there is still Reflex

Because there are still receptors located on

some skin on the tips of

the skin at the tips of the toes, frogs can still

the toes

perceive stimuli and perform reflex responses
to stimuli

Peel off all skin

No
reflexes

Due to the absence of receptors, frogs cannot
perceive stimuli from the environment,
leading to no longer reflexes

5.3. Experiment 3: Determine the role of nerves

Characteristic
Test reflex with
acid

Result

Explain

Reflex. The
reflex time is 3

Frogs still have all the components of a reflex
arc.

seconds
Nerve exposure,

Reflex

Frogs still have all the components of a reflex

test with acid

arc. If the nerve is affected during the
process, there may be no reflex or weak
reflex

Cut the sciatic
nerve

No reflexes

The nerve has been destroyed, the nerve
impulse cannot be transmitted, so there is no
reflex.

5.4. Experiment 4: Determine the role of the central nervous system

Characteristic
When not tying the
thread. Test reflex with
acid

Result
Reflex

Explain
Due to the elements of the reflex arc are still
intact


When tying the thread.

No

Because the nerve impulse has been blocked

Test reflex with acid

reflexes

by the thread, there is no longer reflexes

After removing the thread No
reflexes

It is possible that during the thread ligation
and removal, the nerve has been damaged,
leading to no longer reflexes

Punch the marrow, check

No

Because the marrow has been destroyed, the

the reflex with the frog's

reflexes

frog has no organs to receive, process stimuli

hand

and send feedback, leading to no longer
reflexes.


NERVOUS REGULATION OF CARDIAC ACTIVITY
I.
‐
‐

OBJECTIVE
Observe cardiac activity

Observing the effects of the parasympathetic nerves appear first, then the effects

‐

of the sympathetic nerves through the graph recording the heart's activity.
Determined the role of vagus nerve in cardiac activity regulation

‐ Observe parasympathetic stimulation
II.
PRINCIPLES
Heart rate is controlled by two branches of the autonomic (involuntary) nervous
system: sympathetic nervous system (SNS) and parasympathetic nervous system
(PNS).
●

The sympathetic nervous system (SNS): releases the hormones
(catecholamines - epinephrine and norepinephrine) to accelerate the heart
rate

The parasympathetic nervous system (PNS): releases the hormone
acetylcholine to slow the heart rate
Vagus nerve is a nerve of the parasympathetic nervous system. When

●

stimulated, it secretes acetylcholine to bind to the M receptor on the heart, reducing
the activity of the heart.
III. MATERIALS
‐ Frog dissection kit
‐ Surgical tray, medical gauze, thread, heart apex pin

‐ Ringer solution
‐ Electric Induction Machine, electrics wire, battery,
‐ Frog
‐ PowerLab system
IV. PROTOCOL
Step 1: Destroyed spinal cord
Step 2: Placed the frog on the table to open it’s chest
‐ Use 4 pushpins to hold the limbs
‐ Cut off the skin and the muscle near the sternum
‐ Cut in V shape at the corner of the jaw in order to expose the frog’s heart
Step 3:
‐ After exposing the frog’s heart, a pericardium appeared. Use a medical pin and a
small scissors to cut a longitudinal line to remove the pericardium. (remove the


pericardium to give the heart space to beat. When breaks the negative pressure of
the heart cavity, when pulled, the pericardium will collapse => pressure on the
heart's activity)
‐ Add saline solution or Ringer solution to maintain heart’s beat
Step 4:
‐
‐

Find vagus nerve
Anatomical landmark: vagus nerve is located at the corner of the jaw and crosses
over the deltoid muscle. Cut off the corner of the jaw.

If it's not the vagus nerve, it's most likely a frog's vocal cords. To check if it's the
vocal cords or the vagus nerve, we electrically stimulate that wire.
‐

‐

If the frog's jaw moves, it's the vocal cords
If the frog's heart stops beating for a while and then starts to beat faster again, it's

the vagus nerve.
Step 5: Threaded the thread under the vagus
Step 6: Connect to Power Lab system and analyze results on Lab chart software.
Step 8: Connect the apex cordis to the heart hanger for force measurement. When the
heart contracts, it will act on the transfer lever and will switch to the force analyzer
Do not damage the heart chambers, do not clamp too down on the ventricular
chambers because it will cause different contractions
Step 9: Apply electrical stimulation to the vagus nerve and observe the results.
‐ When the atria contract, a small peak is created.
‐ When the ventricles contract, a large peak is created.
V. RESULT AND CONCLUSION
5.1. Result
The vagus nerve is excited to the threshold: the activity graph of the frog's heart
goes down, the frequency and amplitude both decrease, with an almost flat segment
When stimulation is continued: After the heart stops beating for a while, the heart
beats back to normal
5.2. Explain


Normal cardiac activity. The up-and-down lines of the heart activity graph show
that the parasympathetic nervous system comes first, followed by the sympathetic
nervous system
The sympathetic nervous system (SNS): accelerate the heart rate
The parasympathetic nervous system (PNS): slow the heart rate
Vagus nerve is a nerve of the parasympathetic nervous system. When

stimulated, it secretes acetylcholine to bind to the M receptor on the heart, reducing
the activity of the heart.
Parasympathetic stimulation
‐ In the frog heart, there is an organ similar to the bundle of his in humans, not
‐

controlled by the X cord, it spontaneously pulses to make the heart beat
Synaptic fatigue: because acetylcholine is depleted and not synthesized in time,

‐

this substance is an intermediate of the X cord => the effect of the vagus nerve is
inhibited
Cardiac reflex: more blood returns to the atria, causing the Brain Bridge to
stretch. From this area, impulses are generated, following the sensory nerve of
the vagus nerve to the medulla, inhibiting the vagus nerve, causing the heart to
beat faster.


INSULIN SHOCK THERAPY
I.

OBJECTIVE

‐ Observe the state of mouse after insulin injection
II.
PRINCIPLES
The pancreas is a mixed or heterocrine gland, it has both an endocrine and a
digestive exocrine function.
‐ As a part of the digestive system, it functions as an exocrine gland secreting

pancreatic juice into the duodenum through the pancreatic duct.
‐

As an endocrine gland, it functions mostly to regulate blood sugar levels,
secreting the hormone insulin, glucagon, somatostatin and pancreatic
polypeptide

Insulin: regulate the body’s energy supply by balancing micronutrient levels
during the fed state, such as decreasing the rate of glucose in blood.
Glucagon: promote the conversion of glycogen into glucose, reduces fatty
acid synthesis in adipose tissue and liver as well as promotes lipolysis in these
tissues, causing them to release fatty acids into the bloodstream, where they can be
transported converted into energy for certain essential tissues, such as skeletal
muscle
‐ In blood, the stable sugar level is 0,8 – 1,2 g/l
Under 0,45g/l => insulin shock
Above 1,2g/l => promotes the conversion of glucose into glycogen and other
storage products in the cell
III. MATERIALS
‐ Mouse
‐ Insulin
‐ Glucose solution (hypertonic 30%)
‐ Syringe 1mL
‐ Glucose monitors
‐ Scale
‐ Other items
IV. PROTOCOL
Step 1: Mark different mice: mouse 1 injected with 0.9% saline, mouse 2 injected
insulin marked on the tail
Step 2: Measure the blood glucose of 2 mice before injection by taking blood from

the tail of the mouse and putting it into the blood glucose meter


‐

Mouse 1, without saline injection, had a blood sugar level of 5.0mM/l

‐

Mouse 2, without insulin injection, had a blood sugar of 5.2mM/l

Step 3: Injecting saline into the mouse 1 and injecting insulin into the mouse 2. Be
careful not to bulge the mouse skin when injected subcutaneously.
V.
RESULTS AND CONCLUSION
Mouse 2 after insulin injection:
Have a strong movement
After a period of time, the mouse began to have the phenomenon:
‐
‐

Legs outstretched
The whole body shook, not moving, very poor movement

‐
‐

Had convulsions
The hairs on the nape of the neck stand up

‐ Eyes closed
‐ Cold but sweaty due to lack of energy to generate heat
Compare with mouse 1 as control mouse
‐ Control mouse function normally
Measure the blood sugar of the mouse after injection:
‐ Mouse 1 with saline injection: 5.0 mM/l
‐

Mouse 2 with insulin injection: 3.1 mM/l


EARLY PREGNANCY DIAGNOSIS
I.

OBJECTIVE
Using pregnancy quickstick to diagnose early pregnancy in humans
II.
PRINCIPLE
The diagnosis of pregnancy is based on the hormone HCG secreted by the
placenta:
HCG is produced in the earliest stages of pregnancy, and tells the body not the
shed the inner lining of the uterus that month. As the pregnancy progresses, HCG
supports the formation of the placenta which transfers nutrients from mother to fetus.
From 6-8 days, the zygote begins to nest. However, in the early stages, the
placenta secretes very little HCG hormone, must rely on a very sensitive test kit
measured in the blood to detect the hormone, but cannot measure the amount of HCG
in the urine by regular pregnancy test. Every 2-3 days, hormone levels will double.
When the amount of hormone exceeds the standard threshold of blood sugar, it will
be filtered by the kidneys, not reabsorbed, and will be excreted through excretion. At
this time, the quickstick can be used.

III. MATERIALS
‐
‐

Quickstick
Urine from women suspected of being pregnant

‐ The urine from the control person
IV. PROTOCOL
Step 1: Check the quality of the pregnancy test kit (NSX, HSD…)
Step 2: Dip the pregnancy test stick in the urine cup of the woman suspected of being
pregnant
Step 3: Read the results in 2-5 minutes
Note: Do not dip beyond the reaction zone line
V.
RESULT AND CONCLUSION
5.1. Result:
If the test strip shows 1 line, there are 2 cases:
‐ Non – pregnant
‐ Pregnant but due to testing in the early days of pregnancy, the amount of HCG
residue is not enough to pass the filtering threshold of the kidneys to enter the
urine
If the test strip shows 2 line, there are 2 cases:
‐ Pregnant


‐

False negative

5.2. Explain
The test starts when the urine is applied to the exposed end of the strip. As the
fluid travels up the absorbent fibers, it will cross three separated zones, each with an
important task:
Quickstick including 3 zones
‐ Reaction zone: including Y- shaped proteins called antibodies. Antibodies grab
onto any HCG. Attached to these antibodies is a handy enzyme with the ability

‐

to turn on dye molecules, which will be crucial later down the road. Then the
urine picks up all the AB1 enzymes and carries them to the test zone
Test zone: where the result shows up. Secured to this zone are more Y – shaped
antibodies that will also stick to HCG on one of its five binding sites. This type
of test is called a sandwich assay.
■ If there is no HCG, the wave of urine and enzymes just passes on by.
■

‐

If HCG is present, it gets sandwiched between the AB1 enzyme and AB2 and
sticks to the test zone, allowing the attached dye activating enzyme to do its
job and create a visible pattern.
Control zone: confirms that the test is working properly. Whether the AB1

enzymes never saw HCG, or they are extras because zone 1 is overstocked with
them, all the unbound AB1 enzymes picked up in zone 1 should end up here and
activate more dye. Therefore, if no pattern appears, that indicates that the test was
faulty.
False negative pregnancy test:

The excessive proliferation of cancer cells is responsible for the secretion of HCG
(ex: uterine cancer of testicular cancer…)


=> False negative test
In male, if false negative pregnancy occurs, the possibility of cancer should be
considered
‐ Ectopic pregnancy
‐ IVF injections
Why can the observation time be different?
In the early days of pregnancy, the amount of HCG is not enough to pass through the
filtering threshold of the kidneys to enter the urine. After implantation, HCG levels
double every two to three days.
Future direction
‐
‐

Pregnancy care
Check the indicators: check if the pregnancy has entered the uterus, measure the
fetal heart rate, nuchal translucency (if the nuchal translucency at week 11 is too
large, it must be rechecked. will have to have amniocentesis to check the
chromatogram, must culture for 1 month to check the chromatogram)

‐

Termination of pregnancy if there are too many abnormalities


BLOOD TYPING
I.

OBJECTIVE

‐ Use serum (anti A, anti B and anti AB) to determine blood type
II.
PRINCIPLE
ABO blood typing system
The distinction between blood groups is based on the presence of A and B antigens
on the red blood cell membrane, α, and β antibodies in the plasma

A B

AB

O

Antigens on the red blood cell membrane A B A, B None
Antibodies in the blood plasma

β

α None

α, β

When the A antigen meets the α antibody and when the B antigen meets the β
antibody, an immune interaction reaction will occur, causing the red blood cells to
stick and settle down called agglutination (agglutination)
Principles of blood transfusion
‐ Blood transfusions should be given in the same group

‐ If a non-group transfusion is required, the minimum rule must be followed:
“The donor erythrocytes must not be agglutinated with the recipient serum”.
However, a small amount (250ml) must be infused and given at a very slow
rate.
Diagram for blood transfusion

Rh+ blood group: Has type D antigen
Rh blood group -: No D antigens
III. MATERIALS
‐ Serum
‐ Syringe
‐ Cotton
‐ 90% ethanol
‐ Ether


‐

Glass rod

‐

Microscope slide

IV. PROTOCOL
‐ Prepared the clean microscope slide, which was tucked in 3 positions A, B, and
O separated to 1 from 1.5 cm.
‐
‐
‐

Used 3 different pipette tips, sucked 3 serum samples into 3 positions.
Disinfect fingertips and draw blood.
Use the glass rod to mix the blood with each serum sample.

‐ Swung the microscope slide, waited for 2- 3 mins, then read the result.
V.
RESULT AND CONCLUSION
5.1. Result

Aggregation occurs at three sites: anti B, AB and D.
‐ Agglomeration at anti B, AB blood group B
‐ Anti-D causes agglutination of RBCs with Rh+ group
This person's blood type is B+
5.2. Explain
When antigens and corresponding antibodies meet (A and α; B and β), an immune
interaction reaction causes red blood cells to stick and settle, called agglutination. In
people with type B, there will be B antigen on the surface of red blood cells. Therfore,
when coming into contact with serum containing β antibodies (anti AB and anti B),
it will cause red blood cells to agglutinate.


THE ROLE OF BLOOD COAGULATION FACTORS
I.
OBJECTIVE
‐ Demonstrate the role of coagulation factor
II.
PRINCIPLE
In the blood vessels, blood is always in liquid form to circulate throughout the
body. However, when the body is injured and bleeds, the blood automatically

coagulates into a clot that seals the wound, preventing blood from flowing out,
avoiding blood loss.
Hemostasis is accomplished through three main mechanisms: vasoconstriction,
platelet plug formation, and clot formation
+ Vasoconstriction: As soon as the blood vessel is damaged, the vessel wall will be
constricted, the more damaged the vessel wall, the stronger the contraction.
Vasoconstriction can last for several minutes to several hours. During this time,
platelet plug formation and coagulation may take place.
-> Limits the amount of blood leaving the damaged vessel wall
Platelet plug formation:
‐ Platelet adhesion: When the vessel wall is damaged, exposing the collagen layer,
‐

platelets will come and contact collagen
Platelet aggregation: contact with collagen makes platelets active, releasing

factors such as: ADP, PDGF, Ca2+ that make other platelets come and stick to
them.
=> In this way, more and more layers of platelets come to stick to the lesion to form
a platelet plug
Clot formation: Thromboplastin secreted from the surface of damaged cells
combines with activated Ca2+ to form the Prothrombinase complex. Formation of
Thrombin helps the blood clotting process continue to take place. Thrombin
hydrolyzes fibrinogen and produces fibrin monomer. Then, these fibrins will combine
to form a stable fibrin network that traps blood cells, platelets, and plasma to form
clots.
III. MATERIALS
‐ Test tube rack
‐ Timer
‐ Pipettes

‐ 10% CaCl₂ solution
‐ Blood solution had 5% NaCl and 1% NaNO₃


‐
IV.

Mini Q water

PROTOCOL
Ca 2+
‐

Used 3 pipette, sucked 3mL blood had 1% NaNO₃ into test tube.

‐

Add 0.1mL 10% CaCl₂ solution, mix and use a timer to calculate the time for

coagulation.
NaCl
‐ Use 3 pipette, sucked 1mL blood and had 5% NaCl into the test tube.
‐

Add 5mL miniQ water, mix and use a timer to calculate the time for
coagulation.

Trombin
‐ Collect serum from the blood for natural coagulation.
‐ Use 3 pipette, sucked 1mL blood had 1% NaNO₃ into test tube.

‐ Add 2mL serum, mixed and use a timer to calculate the time for coagulation.
V.
RESULT AND CONCLUSION
5.1. Result

‐ Tubes 1,2,3 have no clotting phenomenon
‐ Tube 4 has coagulation phenomenon
5.2. Explain


For NaCl
‐

In normal blood, the concentration of NaCl is 0.9%. With a concentration of NaCl

‐

solution greater than 5%, it works to prevent the formation of Thrombin, making
the blood unable to clot.
Sodium citrate has the effect of keeping Ca2+ ions in the blood, so the blood

‐

cannot clot.
When diluted with distilled water, the concentration of sodium citrate in table
salt gradually decreases, allowing blood to clot. Therefore the coagulation in the
test tubes increases gradually due to more volume of distilled water added in
each tube.

For CaCl2

‐ When adding CaCl2 solution, which means providing more free Ca2+ ions, the
‐

blood will clot
Ca2+ combines with clotting factors released from platelets to form blood fibrils
that cross each other to form a network that holds blood cells tightly and forms a

‐

clot.
However, the above solution contains 5% NaCl, which has an anticoagulant
effect, preventing the formation of fibrin fibers that prevent blood from clotting.


ECG RECORDING
I.
OBJECTIVE
‐ Record the ECG of the frog's heart and determine the frog's heart rate in 1 minute
II.
PRINCIPLE
In the thorax, the heart is located at an angle α from the longitudinal axis of the
body in the right-to-left direction, with the base of the heart above, the apex below.
The cardiac cycle begins at the base of the heart and gradually spreads to the apex
Unequal excitement between the base and apex of the heart causes an electric
potential, called an electrocardiogram: Using an electrocardiogram to record the
heart, we have an electrocardiogram (ECG).
The electrocardiogram is characterized by a wave consisting of 5 stretches,
denoted PQRST as follows:
‐ P stretch corresponds to atrial activity. The QRS complex corresponds to
ventricular activity. T stretch appear in the dilated phase of the heart, which is the

‐

metabolic potential
The shape of the peak, the distance between the peak in msec, the amplitude of
the peak in mV are important indicators to evaluate the heart's activity.

1. Basic leads
‐ DI: Record from two electrodes placed in the right-left hand
‐ DII: Recording from two electrodes placed in the right hand-left foot
‐ DIII: Record from two electrodes placed in the left arm-left foot
2. Unipolar leads only
‐ aVR: Right hand voltage
‐ aVL: Left hand potential
‐ aVF: Potential in the leg
3. Thoracic unipolar leads
‐ V1: The electrode is placed in the right 4th intercostal space, close to the
sternum border
‐
‐
‐
‐

V2: The electrode is placed in the left 4th intercostal space, close to the sternum
border
V3: The electrode is placed in a straight line connecting V2 - V4
V4: The electrode is placed at the intersection of the straight line from the
center of the left clavicle down to the 5. intercostal space
V5: The electrode is placed at the intersection of the left anterior axillary line
with the transverse line V4