Download Circulatory System

Circulatory System Part 3
Begins
The VAGUS nerve slows me down, while the ACCELERATOR nerve speeds me up.
The heart rate can be controlled by two different mechanisms.
The hormone acetylcholine slows the heart down, while the hormone
epinephrine (adrenaline) speeds it up.
HEART PACEMAKER SA node
The muscles of the heart want to beat
– an intrinsic contraction rhythm. I
need to get them all beating at the
same time. The SA SinoAtrial node (1)
starts the beating of the two atria. The
impulse travels to the AV node (2) and
initiates the contraction of the two
ventricles
LOCATION NOTE
Pacemaker is in wall of
right atrium near
entrance of superior
vena cava
3
5
AV node sends
signal to bundle of
His (3) . Signal
passes through
septum on bundle
branches. Signal
arrives in ventricle
muscle by Perkinje
fibres.
I’m mean but my heart is a NEUROGENIC HEART of
arthropods. Motor neurons outside the heart control the
heart rate
I’m the MYOGENIC HEART of vertebrates. I have the
pacemaker located inside the heart made of special
muscle tissues
I’m getting an ECG
This is an ECG Electrocardiogram. It can
show the electrical activity of the heart
and can be used to tell if there is heart
damage.
PQ contraction of the atria
Atria depolarization
QRS  contraction of ventricles
Ventricle depolarization
T – electrical repolarization
Ventricle repolarization
With the stethoscope, you can hear the heart
sounds. The main sounds are LUB –DUB.
The lub sound is the closing of the
atrioventricular valves (tricuspid and mitral)
and the DUB is the closing of the semilunar
valves (pulmonary and aortic).
If a hissing sound is heard it is called a heart
Murmur and is the result of backflow of blood
through a leaky and defective heart valve. Most
heart murmurs, however, are not serious enough to
need surgery.
BLOOD PRESSURE You can
determine this with the
sphygmomanometer (BPCuff)
and a stethoscope.
Mercury
above
120 mm
1st –Cut off
arterial blood
flow by inflating
cuff above
120mmHg. Cuff
pressure exceeds
arterial pressurecauses mercury
to rise 120mm+
in the column
Read the step 2 scale
and step 3 scale . Did you
get 120mmHg systolic
and 80 mmHg diastolic?
120/80 is average for a
healthy male
Listen with
stethoscope
2nd
Release pressure
slowly and listen
for sounds of
blood flow.
When sound is
heard, this is the
systolic pressure
reading
3rd
Loosen the cuff
further until blood
flows freely and the
sounds disappear.
This is the diastolic
pressure.
You might wonder why taking the blood pressure is so important.
There are several reasons why.
Blood pressure must be maintained for survival and is a direct result of the
pumping action of the heart. CARDIAC OUTPUT
Blood pressure also results from PERIPHERAL RESISTANCE.
Contraction of smooth muscle around the arterioles reduces the blood
vessel diameter, increasing blood pressure. Smooth muscle relaxation,
causes the blood vessel to dilate and decrease blood pressure.
BP is
dropping
Blood vessel diameter is affected by both nervous, hormonal action
drugs and other signals. Ex stress elevates BP by increasing cardiac
output and constricting blood vessels.
Blood pressure decreases with blood loss. Internal bleeding or
external haemorrhage can be detected by dropping blood
pressure. A very low blood pressure can lead to cardiac arrest.
So this information is very important for medical intervention
Add more blood volume. Start the
transfusion
Extreme Hypertension at 200/120 mmHg very risky
Blood pressure
will be too high all
the time if a
person has
chronic
hypertension
(high blood
pressure). Blood
pressure may be
160/100 mmHg
on a regular
basis. This is a
danger for heart
disease, heart
failure, stroke,
aneurysm, and
kidney failure.
The blood
vessels narrow
and lose their
elasticity.
PLATELET
AGGREGATION
AND
THROMBOSIS
PLATELETS
STIMULATE the
migration and
growth of smooth
muscle
These cholesterol plaques are carried by LDL low
density lipoproteins in the bloodstream. When
they develop in the heart they can result in a
coronary infarction (heart attack) as a result of a
coronary artery thrombosis (blood clot) which
blocks delivery of oxygen to the heart muscle. If
this same even happens in the brain, it is a stroke.
Take a look at these arteries.
They have been narrowed
considerably by the
accumulation of cholesterol
deposits. This would increase
the blood pressure of the
artery. It is increased even
more as the cholesterol
calcifies, hardening the
artery and causing it to lose
its flexibility .
A thrombosis is a
blood clot inside
the blood stream
usually caused by
platelets adhesion
to the rough
surface of a
plaque and the
resultant clotting
process.
TODAY SHOW ANCHOR
DAVID BLOOM IN IRAQ
If you are sitting for a long
time as on an airplane or in
David Bloom’s case a cramped
armoured personnel carrier, it
is recommended that you get
up and stretch regularly to
avoid potential blood clots.
The thrombosis does not even have
to develop in the heart or brain to be
fatal. David Bloom died when a clot
developed in his lungs and travelled
to his heart. When the clot breaks
off and travels it is called an
embolus. This embolus can then
clog a critical artery as it passes into
the narrower lumen. He died as a
result of a pulmonary embolism. It’s
a sad state of affairs when
components of the immune
system(platelets) lead to death, but
if the blood vessels would have been
clear of plaques, this probably would
not have happened.
You may ask. “How do I know if I am having a heart
attack.” Here are some of the main symptoms.
Remember, not all are necessary to indicate a
myocardial infarction
Chest pain – gradual tightness pressure or squeezing due to
ischemia (lack of blood flow to the heart). Often radiates to
the left arm but sometimes the lower jaw, neck, back or
epigastrium where it mimics heartburn.
Shortness of breath
Excessive sweating
Grey skin tone
Weakness
Nausea
Vomiting
Sleep disturbances
Anxiety
If you have these symptoms, take it seriously. Do not push
yourself. Contact medical services immediately. Here are some
things that can be done immediately
Take a baby aspirin – it will act as a blood
thinner to stop blood clots from lodging in
arterioles.
Site of
blood clot
blockage.
CPR can be conducted on an unconscious
patient without a pulse.
If a defibrillator is available, the heart
beat may be restored with a burst of
high voltage. Remember, the heart is not
dead after a heart attack, it has just been
allowed to vibrate out of rhythm. (called
ventricular fibrillation)
Site of heart damage due to
blockage. This muscle is dead
(replaced be scar tissue) and
will no longer pump. The
heart is weakened
Once the
suspected heart
attack patient is at
the hospital, an
ECG can be done
and abnormalities
in the graph may
reveal if a heart
attack has
occurred.
We can also detect
if there has been a
heart attack by a
blood test that
checks for a
particular blood
protein found after
a heart attack
If we suspect that
there may be a a
blockage the
angiograph can be
done.
This is an angiograph. A
catheter with dye is inserted
into an artery and a sequence
of X rays are performed. The
picture clearly shows coronary
artery blood flow and blockage
areas.
If there is a
blockage there
are options.
Angioplasty and
stents
Coronary bypass
surgery
Hidden Biology in intellectual literature and movies
Original Willy Wonka and the Chocolate factory completed
with input from the original book author Roald Dahl.
When Violet Beauregarde is interviewed on T.V. upon
discovering a Golden Ticket, she exclaims:
Now this piece of gum here is one I've been chewing
for three months solid, and that's a world record. It's
beaten the record held by my best friend Miss
Cornelia Prinzmetel, and was she mad! Hi, Cornelia,
how are you sweetie?
Prinzmetal's Angina, or coronary artery spasm, is an
uncommon condition seen in both men and women.
Episodes of typical (though severe) angina are
triggered when one of the major coronary arteries
suddenly goes into spasm, temporarily shutting off
blood flow.
Note: coronary
arteries to feed
the heart muscle
Here are some
very important
blood vessels to
the head. The
carotid arteries
lead through the
neck up to the
oxygen sensitive
brain. Fresh blood
is constantly
delivered
immediately after
each heart beat.
Subclavian
arteries service
the arms.. Blood
returns to me
from the head
through the
jugular veins.
Carotid arteries
Here are the
rest of the
blood vessels.
The important
ones are
marked
Dorsal aorta
Renal artery
Femoral artery
Get yourself
familiar with
these blood
vessels. Can you
figure them
out?
A - pulmonary artery
B- inferior vena cava
C – hepatic portal vein
D – renal vein
E – pulmonary vein
F - Aorta
G – Hepatic arteries
H – mesenteric arteries
hepatic portal vein
Deoxygenated blood
B- inferior vena cava
Deoxygenated blood
Right atrium
Deoxygenated blood
Tricuspid valve
Deoxygenated blood
Right ventricle
Deoxygenated blood
Aortic valve
Deoxygenated blood
Pulmonary artery
Deoxygenated blood
Try to trace a blood cell
from the hepatic portal
vein to the left common
carotid artery
Lungs
Pulmonary vein
Oxygenated blood
Left atrium
Oxygenated blood
Mitral valve
Oxygenated blood
Left ventricle
Aortic valve
Oxygenated blood
Oxygenated blood
Aorta
Oxygenated blood
Left common carotid
Oxygenated blood
You may also be
asked when the
blood is
oxygenated or not
oxygenated.
Umbilical arteries(2)
Deoxygenated blood
placenta
Umbilical vein
Oxygenated blood
Inferior vena cava
Oxygenated blood
All 4 heart chambers
Vein with
oxy blood
Oxygenated blood
You really have to know
your stuff to understand
fetal circulation. Here the
fetus does not receive
oxygen in the pulmonary
cycle- the fetus is in the
uterus and does not obtain
oxygen through its lungs. It
is totally dependent on the
oxygen supply it receives
when it sends blood to the
placenta. Blood is actually
diverted away from the
useless lungs by the ductus
arteriosis. Once the baby
breathes, this artery
degenerates.
Well that’s all for now.
Circulation
ends