Download The Cardiovascular System

The Cardiovascular
System
Lindsey Bily
Anatomy & Physiology
Austin High School
What is Blood?
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It is the delivery service for the body.
Picks up food and oxygen from the respiratory and
digestive system and delivers them to the cells.
Picks up wastes from the cells and takes them to the
excretory organs.
Transports hormones, enzymes, buffers, and other
substances vital to life.
Heat regulating mechanism. It can absorb lots of
heat without raising the fluid temperature.
What is Blood?

8% of a person’s body weight is blood

Male- 5-6 L, female- 4-5 L

When you donate blood, they generally take 1 L
from you. That is about 10% of your total blood
volume.
What is Blood?

Composed of…

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Red blood cells (RBCs)- erythrocytes
White blood cells (WBCs)- leukocytes
Platelets- thrombocytes
Plasma is the fluid portion and is mostly water
A
B
A: red blood cells
B. Blood smear with
all components
C. Platelets
D. White blood cells
C
D
Red Blood Cells
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Do not have ribosomes, mitochondria, or many other
organelles.
Contain lots of hemoglobin. That’s why they are red.
They can change shape to fit through tiny blood
capillaries.
Testosterone may stimulate RBC production-males
typically have more RBCs than women. (5,500,000
vs. 4,800,000 per/mm3
Red Blood Cells
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Transport oxygen and carbon dioxide.
The total surface area of all the RBCs in an adult is
equal to an area larger than a football field for
exchanging gases!
Each hemoglobin molecule can carry 4 oxygen or
carbon dioxide molecules.
Anemia: having a hemoglobin content of less than
10g per 100/mL of blood (normal~ 12-16 g per
100/mL)
Red Blood Cells
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Erythropoiesis: RBC formation
Occurs in the red bone marrow and the process takes
about 4 days.
Each minute of our life, we replace 200 billion RBCs
that have been destroyed!
If the blood oxygen level decreases (higher altitudes)
we make more RBCs.
The life span is 105-120 days. They usually break
apart in the capillaries as they age.
Macrophages lining the blood vessels phagocytose
them.
Sickle Cell Anemia
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Due to an abnormal type of hemoglobin.
Causes the RBC to change shape and get
stuck in capillaries.
Inherit the gene from 1 parent and you have a
less severe form called “sickle cell trait”.
Inherit from both parents and you have a more
severe case.
Causes strokes, swelling, ulcers, etc. due to
blockage in the blood vessels.
Sickle Cell Anemia
Spleen with sickle
cell anemia
White Blood Cells
•
•
There are 5 types of WBCs that each have a
different form of protection for the body.
Some destroy bacteria, parasitic worms,
ingesting inflammatory chemicals, contain
histamine, eat viral infected cells and cancer
cells.
WBCs are formed in red bone marrow and in
lymphatic tissue.
White Blood Cells
Platelets
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They stick together to form plugs or clots to
stop blood flow.
Usually form at the site of injury.
We are always having microhemorrhages in
our capillaries. Without platelets we could
bleed to death.
Formed in the red bone marrow, lungs, and
spleen and “live” about 7 days.
Platelets
Blood Types
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Blood type refers to the antigens that are attached to
the RBC membrane. (A, B or Rh)
Type A: A antigens on the RBC
Type B: B antigens on the RBC
Type AB: both A & B on the RBC (universal
recipient)
Type O: neither antigens (universal donor)
Blood plasma contains antibodies that are different
from the antigens on the RBCs so that you don’t
attack your own RBCs.
Blood Types
Blood Types
The Rh System
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Rh + blood has the Rh antigen on the RBC. Rhdoesn’t.
Plasma does not have antibodies against Rh
naturally. Only if a (-) person has been in contact
with Rh (+) blood may they make the antibodies.
Sometimes a mother could be Rh- and her baby is
Rh+. During delivery, the blood mixes, and the mom
develops the antibodies.
The first baby is born fine, but if the mother has
another Rh+ baby in the future, the baby is at risk of
dying.
Plasma
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Liquid part of the blood.
contains…
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90 % water
10% solutes
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Proteins that regulate blood clotting and help with immunity
Glucose, amino acids, lipids
Urea, uric acid, creatinine and lactic acid
Oxygen and carbon dioxide
Hormones and enzymes
Blood Clotting (Coagulation)
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We need our blood to
clot to stop bleeding and
prevent loss of body
fluid.
Clotting is a series of
chemical reactions that
happen really fast that
causes a net of fibers to
be built which traps
RBCs.
Blood Clotting
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Proteins involved…
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Prothrombin
Thrombin
Fibrinogen
Fibrin
Blood Clotting
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You need calcium in order for some of the chemical
reactions to occur. If you have a low blood calcium
level, you may have trouble clotting.
The pale yellowish liquid left over after the clot has
formed is blood serum. It is the blood, minus the
blood cells and clotting elements.
You need Vitamin K for the liver to make the
clotting proteins. You get this from foods (broccoli,
cabbage, asparagus, okra, beans, etc..) and also
bacteria in your gut make it.
Opposing Clotting
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We only want our blood to clot under certain
conditions.
Normal blood vessels are very smooth, so
platelets can’t attach. That makes sure
clotting is not activated.
Heparin is an anti-thrombin in blood that
keeps it from clotting.
Promoting Clotting
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A rough spot in the blood vessel lining will cause
clotting as will an abnormally slow blood flow.
Atherosclerosis causes rough spots due to the
cholesterol-lipid plaques that have built up.
People who are immobile can get clots (thrombosis)
since blood flow decreases.
Once started, a clot continues to grow unless
medicine is taken to stop it.
Blood Disorders
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Most blood disorders are due to the tissues not
forming blood cells properly.
If a blood disorder is suspected, bone marrow
is taken from the pelvis and tested.
A bone marrow transplant may be required.
RBC Disorders
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Anemia: inability to carry sufficient oxygen to
the body’s cells.
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Polycythemia: too many RBCs and it becomes too thick to flow
properly.
Aplastic anemia: too few RBCs. Causes by destruction of bone
marrow by drugs, toxic chemicals, radiation, or cancer.
Pernicious anemia: low # of RBCs. Deficiency of Vitamin B12.
Usually due to a problem with the stomach that doesn’t allow you to
absorb it.
Folate-deficiency anemia: low # of RBCs due to a deficiency in folic
acid (Vitamin B9). Common in alcoholics and other malnourished
individuals.
Hemoglobin Problems
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Iron-deficiency anemia: too little iron means
that you can’t make hemoglobin.
Sickle Cell Anemia
Thalassemia: Similar to sickle cell anemia.
Abnormal hemoglobin causes changes in
RBC shape.
WBC Disorders
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Leukopenia: too few WBCs (HIV/AIDS).
Leukocytosis: too many WBCs (usually
caused by bacterial infection).
Leukemia: a group of malignant disorders
where adult stem cells replace normal cells.
They can eventually leave the bone marrow
and travel to other parts of the body.
Clotting Disorders
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Thrombus: clot that stays in the place where it was
formed. The condition is called thrombosis.
Embolus: When the clot dislodges and circulates
through the bloodstream. Called an embolism.
Drugs that can prevent clotting are Heparin (prevents
prothrombin from turning into thrombin) and
Coumadin (prevents Vitamin K from stimulating the
liver to produce clotting proteins).
Clotting Disorders
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Hemophilia: X-linked disorder and affects 1
in 10,000 males. Failure to produce 1 or more
of the clotting proteins.
Thrombocytopenia: low levels of platelets.
Caused by destruction of bone marrow due to
drugs, immune system diseases, chemicals,
radiation or cancer.
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Bleeding from many small blood vessels in the
body.
The Heart
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4 chambered pump the size of a fist.
Weighs 310g (males) and 225g (female)
Heart Coverings
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Pericardium-sac that surrounds the heart. Contains
pericardial fluid that protects the heart from friction while
pumping.
Myocardium- the bulk of the heart wall made up of
cardiac muscle .
Endocardium- inner layer of the heart. Very delicate layer.
Chambers of the Heart
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4 Chambers
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2 upper: right and left atria
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They receive the blood from
the body
2 lower: right and left
ventricles
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They receive blood from the
atria and pump it out to the
lungs and the rest of the
body
Valves of the Heart
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The valves permit blood flow in one direction only.
2 Atrioventricular Valves: Also called “cuspid”
valves
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Right AV Valve (tricuspid)-right atrium to right ventricle
Left AV Valve (bicuspid)-left atrium to left ventricle
2 Semilunar Valves
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Pulmonary Semilunar valve: right ventricle to pulmonary
artery
Aortic Semilunar Valve: left ventricle to aorta
Valves of the Heart
Blood Flow
Blood Supply to Heart Tissue
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The heart muscle cells (myocardium) receive blood
via the coronary arteries that branch off of the aorta.
The left ventricle cells receive the most blood
because it does the most work.
The atria receive blood from a small branch off the
coronary arteries.
The right coronary artery is dominant in about 50%
of all hearts, left 20% and in 30% neither is
dominant.
Blood Supply to the Heart
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There are few connections between the
coronary arteries.
If the main route is blocked, there are few
detours.
Myocardial Infarction (MI): Death of oxygen
deprived heart muscle cells. This is a heart
attack.
Blood Supply of the Heart
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Cardiac Veins
surround the heart
and once blood has
supplied the cells
with oxygen, they
enter the vein and
go back to the right
atrium.
Heart Conduction System
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Sinoatrial Node (SA node): “pacemaker” of the
heart. Sets up the action potential and causes atria to
contract.
Atrioventricular Node (AV Node): small mass of
special cardiac muscle tissue that lies at the lower
part of the right atrium.
Atrioventricular Bundle (AV Bundle): Action
potential passes to the ventricles and then down the
Purkinje Fibers to cause the ventricles to contract.
Heart Conduction
Blood Vessels
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Carry blood to and from the heart.
Arteries-carry blood away from the heart. All
arteries EXCEPT the pulmonary artery carry
oxygenated blood.
Veins-carry blood to the heart. All veins
EXCEPT the pulmonary vein carry
deoxygenated blood.
Blood Circulation
Blood leaves the heart
Arteriesarteriolescapillariesvenulesveins
back to the heart
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Functions of the Blood Vessels
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Capillaries: microcirculation to every cell
Arteries: “distributors”. Arterioles regulate
blood pressure by acting as resistance vessels
for the capillaries.
Veins: “collectors and reservoir vessels”.
They can stretch called capacitance.
Major Blood Vessels
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Aorta: serves as
the main trunk of
the entire systemic
arterial system.
Blood Vessels
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The main arteries and veins lie deep in the
body alongside bone- deep veins and arteries
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Superficial veins and arteries are the ones that
are closer to the skin and you can see.
Hepatic Portal System
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Veins from the spleen, stomach, pancreas,
gallbladder and intestines send their blood to the
liver for filtering via the Hepatic Portal Vein.
Purpose:
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Liver removes excess glucose from the digestive system
blood after a meal.
Liver puts glucose back into the blood when levels are
low.
Toxic molecules such as alcohol are partially removed or
detoxified before blood goes to the rest of the body.
Hepatic portal circulation. In this unusual circulatory route, a vein is located between two capillary beds.
The hepatic portal vein collects blood from capillaries in visceral structures located in the abdomen and
empties it into the liver. Hepatic veins return blood to the inferior vena cava. (Organs are not drawn to scale.)
Fetal Circulation
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Fetal blood gets oxygen and food from the
mom’s blood as opposed to its own lungs and
digestive organs.
Fetuses have additional blood vessels to do
this.
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Umbilical arteries (2)
Umbilical vein
Ductus Venosus
Fetal Circulation
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Umbilical arteries: carry fetal blood to the placenta.
Placenta: Attached to the uterine wall and exchanges oxygen
and nutrients between the mom and baby. No mixing of the
blood!
Umbilical vein: returns oxygenated blood from the placenta
to the baby.
Ductus Venosus: blood from the umbilical vein goes here and
bypasses the liver.
Foramen ovale: opening in the septum between the right and
left atria so that blood bypasses the fetal lungs.
Ductus arteriosus: Connects the pulmonary artery to the
descending aortic tract. Another way to bypass the lungs.
Fetal Circulation: Most fetal blood is a mixture
of oxy and deoxy blood so it is shown as purple.
Changes After Birth
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Once the umbilical cord is cut,
none of the fetal structures are
needed.
The placenta is shed with the
mother’s afterbirth.
The blood vessels become
fibrous cords in the liver.
The foramen ovale begins to
close once the baby takes its first
breath and takes 9 months to
fully close.
Disorders
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Pericarditis: inflamed pericardium. Caused by
trauma, virus, bacteria, tumor and causes
severe chest pain because the layers rub
together every time the heart beats.
Pus, pericardial fluid, or blood can
accumulate interfering with the heart to pump
and begins to compress it called cardiac
tamponade.
Disorders
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Stenosed valves: valves that
are narrower than normal so
they slow blood flow from the
chamber.
Rheumatic heart disease:
caused by a delayed
inflammatory response to a
Strep infection. Occurs mostly
in children. The valves become
inflamed and can result in
permanent damage in the
valve, the myocardium, or
chordae tendinae (heart
strings).
Disorders
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Mitral Valve Prolapse: The mitral (bicuspid) valve’s
flaps extend back up into the left atrium. You get
backflow of blood or leaking of the valve. Most
people don’t develop any symptoms, but some have
chest pain and fatigue.
Aortic regurgitation: Leaky aortic semilunar valve.
Blood flows back from the aorta to the left ventricle.
You have too much blood in the left ventricle now,
so it gets bigger to compensate as well as increases
its contraction strength. This can stress the heart and
cause some cells to die.
Mitral Valve Prolapse (above)
Aortic Regurgitation (right)
Disorders
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Coronary Artery Disease
(CAD): a condition where
blood flow to the heart is
reduced.
Can be caused by…
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Coronary embolism or
thrombus blocking blood
flow.
Atherosclerosis: “hardening
of the arteries” due to lipids
building up on the sides.
Disorders
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Angina pectoris: severe
chest pain that is felt when
the coronary artery is not
delivering enough blood to
the heart.
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Coronary Bypass Surgery:
Veins are harvested from
other parts of the body to
create “detours” to bypass
the clogged coronary arteries.
Disorders
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Congestive Heart Failure: Inability
of the left ventricle to pump blood
well.
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Usually due to myocardial infarction (MI)
caused by CAD.
Causes the body to retain fluids.
Pulmonary edema: fluid buildup around
the lungs
Patients may be candidates for a heart
transplant or heart implant.
Heart transplants are not very successful
because the body’s immune system tends
to reject the new heart.
Heart implants are machines that don’t
have any external pumps. External battery
packs recharge the small internal battery.
Disorders
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Arteriosclerosis: “hardening of the arteries” by
calcium deposits which reduces blood flow to
tissues. The tissues may die (necrosis) and gangrene
may develop.
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Develops with advanced age, diabetes, high blood
pressure, and smoking.
Angioplasty: procedure to open up the narrowed arteries.
A balloon can be inserted and inflated opening up the
artery.
Disorders
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Aneurysm: section of an artery has become
abnormally wide due to weakening of the
arterial wall.
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Promotes the formation of a thrombus.
The artery can burst and cause internal bleeding
Disorders
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Varicose veins: enlarged veins where blood
tends to pool. The valves in the veins then get
leaky and have a hard time getting blood back
to the heart.
Disorders
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Hemorrhoids: varicose veins in the anal canal.
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Caused by excessive straining during defecation.
Hemodynamics
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How we achieve blood flow
and vary the volume and
distribution of the blood
circulated.
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Active cells-more blood
Inactive cells-less blood
Conduction

Remember the 4 structures…
 Sinoatrial node (SA node): The
Pacemaker
 Atrioventricular node (AV node)
 Atrioventricular Bundle (AV
Bundle or Bundle of His)
 Purkinje fibers (Bundle branches)
These structures are specialized
cardiac cells that don’t contract.
They are there to propagate action
potentials through the heart.
Conduction

The SA node’s normal intrinsic heart rate is
70-75 beats per minute (bpm) at rest.

If the SA node cannot create an impulse, one
of the other structures will assume the duty.
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However, they beat more slowly at 40-60 bpm
Electrocardiogram (ECG or EKG)
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The impulses created in the heart cause tiny
electrical currents to spread to the surface of the
body.
We can take a graphic record of the heart’s electrical
activity with an electrocardiogram.
ECG Waves
Composed of the P wave, QRS complex, and T wave
P wave: The depolarization of the atria (becoming more -).
Showing the impulse traveling from the SA node
through the atria.
QRS complex: ventricular depolarization and atrial
repolarization
T wave: repolarization of the ventricles
Cardiac Dysrhythmia
Dysrhythmia: abnormal heart rhythm.
AV Node Heart block: impulses can’t get to
the ventricles. The ventricles contract much
slower than normal.
Usually a pacemaker is needed.
Bradycardia

Slow heart beat– below 60
bpm.
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We reach bradycardia during
sleep and athletes can reach it
while awake, but resting.
Other than that, you could have
a damaged SA node or there
may be abnormal autonomic
control.
Tachycardia

Very rapid heart beat– more
than 100 bpm
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Normal during and after exercise
and during stress response.
Abnormal tachycardia is due to
improper autonomic control,
blood loss or shock, drugs and
toxins, and fever.
Fibrillation-cardiac cells contract out
of step with each other.
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Atrial fibrillation: Abnormal atrial contraction
and so it does not pump blood well. Can be
controlled by drugs.
Ventricular fibrillation is deadly because the
ventricles stop pumping blood to organs.

Defibrillation: application of an electric shock to
force the fibers to contract together.
Atrial
fibrillation
Ventricular
fibrillation
Cardiac Cycle

A complete heartbeat is 1 cardiac cycle.
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1.
2.
3.
4.
5.
Contraction: systole
Relaxation: diastole
Atrial systole: contraction of the atria (P wave)
Isovolumetric Ventricular Contraction: The ventricles fill with the
same volume of blood and then they contract
Ejection: semilunar valves open and blood is ejected from the heart.
There is always a volume of residual blood left in the ventricles after
this.
Isovolumetric Ventricular Relaxation: the semilunar valves close and
the AV valves open.
Passive Ventricular Filling: AV valves open and ventricles fill
Heart Sounds

“Lub dub”
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Lub: contraction of the ventricles and
closing of AV valves
Dub: closing of the semilunar valves
If you have a heart murmur, the heart
sounds differently and you could have
incomplete closing of the valves or
stenosis of the valves.
Factors that Affect Heart Rate
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Parasympathetic nervous system releases
Acetylcholine to inhibit the heart beat through the
vagus nerve.
Sympathetic nervous system releases
Norepinephrine to stimulate the heart beat through
the cardiac nerve.
There are pressure receptors (baroreceptors) located
in the aorta and carotid arteries that detect changes in
blood pressure, and adjust the heart rate to get it
back to normal.
Factors that Affect Heart Rate
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Emotions:
 Anxiety, fear and anger: increase heart rate
 Grief and depression: decrease heart rate
Exercise: you release epinephrine and that stimulates the
heart
High blood temp and stimulation of skin heat receptors- fast
heart rate
Low blood temp and stimulation of skin cold receptors- slow
heart rate
Pain: sudden intense pain from the visceral organs slow the
heart rate and can cause fainting.
Blood Pressure

Measured with a sphygmomanometer and is measured in
mmHg.
 The cuff is wrapped around the brachial artery in the
upper arm.
 The air is pumped into the cuff until it compresses the
artery and no pulse can be heard through a stethoscope.
 Air is then released until the artery opens up a little and
you hear a tapping sound. This is the systolic pressure
(ventricles contracting)
 The tapping sound changes to very muffled sounds until
they disappear and this is the diastolic pressure (ventricles
relaxing)
Blood Pressure

Normal adult BP is 120mmHg systolic and
80mmHg diastolic (120 over 80 or 120/80).
Pulse


Pulse is the expansion and then recoil of the arteries as blood
is pumped.
You can feel your pulse several places in the body.
 Radial artery-wrist
 Temporal artery- temples
 Facial artery-jawbone
 Popliteal artery- behind the knee
 Posterior tibial artery- inner ankle bone
 Dorsalis pedis artery- upper surface of the foot
Pressure Points

There are 6 points where you can stop arterial
bleeding.
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Temporal artery
Facial artery
Common carotid artery
Subclavian artery
Brachial artery
Femoral artery
Disorders

Hypertension (HTN): high blood pressure
(over 140/90 mmHg)

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90% of patients have an unknown cause
10% of patients have HTN due to kidney disease,
hormonal problems, or birth control pills, or
pregnancy.
Genetics play a large role. Seen in males more
than females and in older people.
Risk factors: high stress, smoking, obesity, high
alcohol and caffeine intake, and lack of exercise.
Disorders

HTN is usually a “silent killer” because it
doesn’t have any major symptoms.

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Heart disease
Heart failure
Kidney failure
stroke
Heart Failure

Inability of the heart to pump enough blood to
sustain life. Due to…



Congestive heart failure (left ventricle failure)
Cardiomyopathy (disease of the myocardium)
Valve disorders
Shock

Failure of the circulatory system to deliver enough oxygen to
cells.
 Cardiogenic: due to heart failure
 Hypovolemic: loss of blood volume in the vessels
 (blood loss, burns, chronic diarrhea or vomiting,
dehydration)
 Neurogenic: dilation of the blood vessels, so blood
pressure gets too low. The parasympathetic nervous
system does not balance out the sympathetic.
 Anaphylactic: allergic reaction that causes blood vessels
to dilate
 Septic: toxins in the blood dilate the blood vessels.