Transcript Horlings Heart

Heart
CIRCULATORY SYSTEM
FUNCTIONS:
Transport (nutrients, wastes, oxygen,
CO2, hormones)
Immunity (leukocytes, antibodies)
Temperature regulation (when you
are cold, blood vessels constrict;
when hot, they dilate)
Penile erection
COMPONENTS OF
CIRCULATORY SYSTEM
Heart
Blood
Blood vessels (arteries, capillaries,
veins)
Lymph vessels and nodes
THE HEART
The heart is the simplest organ in the body.
It does only one thing: pumps blood.
It beats 42 million times a year.
It’s about the size of your clenched fist.
Some of you have big fists, some have
smaller fists.
Its location is deep to the sternum. Take
your left fist and place it on the sternum,
then angle the bottom of your wrist to the
left. When you say the Pledge of
Allegiance, your hand is not over your
heart. It’s not on the left, it’s in the center.
Location of the Heart in the Thorax
Figure 18.2
Pericardium
Layers of
tissues
around the
heart:
Heart muscle
PERICARDIUM
Surrounds the heart (like a heart in
baggie).
The function is to lubricate the heart, so
as it beats, it won’t rub against
anything.
The pericardium is divided into two
layers with a space between them
filled with fluid:
PARIETAL PERICARDIUM
PERICARDIAL CAVITY
VISCERAL PERICARDIUM
PARIETAL PERICARDIUM
This is actually the outermost layer of
thoracic cavity. Two layers:
SEROUS LAYER (simple squamous
epithelium). Watery fluid.
FIBROUS LAYER (moderately dense
fibrous connective tissue)
VISCERAL PERICARDIUM
(aka EPICARDIUM)
Outermost layer of heart.
It also has two layers:
– SEROUS LAYER
– FIBROUS LAYER
Pericardium
Layers of
tissues
around the
heart:
Heart muscle
Structure of the Heart –
Coverings
Figure 18.3
MYOCARDIUM
The heart muscle itself
(myocardium) is made of what
tissue?
Cardiac muscle.
ENDOCARDIUM
The lining on the inside of the heart.
Has two layers:
ENDOTHELIUM (simple squamous
epithelium that provides a smooth
surface for the blood to pass by)
Loose fibrous connective tissue (deep
to the endothelium)
PERICARDITIS
Inflamed outer layer of heart.
Fluid accumulates in pericardial cavity,
putting pressure on heart  improper beat
Pericarditis can be caused by damage to
the blood vessels  blood leaks into
pericardial cavity  pressure  improper
beat.
Pericarditis can lead to pericardial friction
rub, adhesions, and additional excess fluid
in the pericardial cavity.
PERICARDITIS
CARDIAC TAMPONADE: In severe
cases of pericarditis, or if there is a
stab wound to the heart wall that
causes fluid to exude into the
pericardial cavity.
The excess fluid compresses the
heart and diminishes the heart’s
ability to pump.
Treatment is to stick a needle in the
cavity and drain the fluid.
ENDOCARDITIS
More serious:
Bacteria enter bloodstream (dental
procedures, IV drug abuse, catheter)
 damage to lining and valves 
blood clots.
Those who already have damaged
heart valves need prophylactic
antibiotics.
THE HEART IS TWO PUMPS:
LEFT AND RIGHT
LEFT PUMP:
From lungs to body
RIGHT PUMP:
From body to lungs
The Pulmonary and Systemic
Circuits
Figure 18.1
Heart Chambers
• Each pump has two types of chambers:
ATRIUM and VENTRICLE
SVC
RA
IVC
RV
Tricuspid valve
Pulmonary
artery
Pulmonary
vein
LA
LV
Bicuspid valve
Aorta
Blood Flow
Deoxygenated blood from body
enters the RA through the superior
and inferior vena cava.
It pours through the TRICUSPID
(RIGHT AV) VALVE into the right
ventricle.
Right atrium contracts, pushes blood
into the right ventricle  ventricle
expands, then contracts with force.
To prevent the blood from going back
up into the atrium, need a valve.
VALVES
Valves are like a swinging door that can
only open one direction. But you can push
against this door, since it’s only tissue.
But if you tie a rope to the doorknob, it
won’t be able to go the wrong way. Rope =
CHORDAE TENDONAE, which is attached
to pieces of myocardium called
PAPILLARY MUSCLES.
The contraction pulls on the chordae
tendonae to close the valves, preventing a
PROLAPSED VALVE (turned inside out).
Valves
Figure 18.9a
Function of the Atrioventricular
Valves
Figure 18.9b
Heart Valves – Valve Structure
Figure 18.8a
What is an artery?
An artery is a vessel that carries
blood AWAY from the heart. It does
not matter if it is oxygenated or
deoxygenated blood.
A vein is a vessel that carries blood
TOWARD the heart. It does not
matter if it is oxygenated or
deoxygenated blood.
Blood Flow
• With the ventricular contraction, blood can go only one
way: into the PULMONARY ARTERY (one of the few
arteries with deoxy blood).
SVC
RA
IVC
RV
Tricuspid valve
Pulmonary
artery
Pulmonary
vein
LA
LV
Bicuspid valve
Aorta
• When the ventricles relax, the PULMONARY
SEMILUNAR VALVE close to prevent blood
from going from the pulmonary artery back
into the right ventricle.
.
SVC
RA
IVC
RV
Tricuspid valve
Pulmonary
artery
Pulmonary
vein
LA
LV
Pulmonary
semilunar valve
Bicuspid valve
Aorta
Function of the Semilunar Valves
Figure 18.10a, b
Blood Flow
When the ventricles relax, the
PULMONARY SEMILUNAR VALVE
closes to prevent blood from going from
the pulmonary artery back into the right
ventricle.
Do the semilunar valves have a chordae
tendonae?
No; the blood is not being forced back (with
a contraction), it just falls back with gravity,
so there’s not as much pressure.
• Blood then goes into lungs, gets oxygenated,
and returns on the left side through the
PULMONARY VEINS (one of the few veins with
oxy blood), into the LEFT ATRIUM.
Lungs
SVC
RA
IVC
RV
Tricuspid valve
Pulmonary
artery
Pulmonary
vein
LA
LV
Pulmonary
semilunar valve
Bicuspid valve
Aorta
• From the LEFT ATRIUM, it goes through
the MITRAL VALVE (BICUSPID VALVE)
into the LEFT VENTRICLE(there are also
chordae tendonae here), which contracts.
SVC
RA
IVC
RV
Tricuspid valve
Pulmonary
artery
Pulmonary
vein
LA
LV
Pulmonary
semilunar valve
Bicuspid valve (Mitral)
Aorta
• Therefore, the left ventricle is the chamber
which is responsible for generating the
largest pressure upon contraction.
SVC
RA
IVC
RV
Tricuspid valve
Pulmonary
artery
Pulmonary
vein
LA
LV
Pulmonary
semilunar valve
Bicuspid valve (Mitral)
Aorta
• The blood then goes past the AORTIC
SEMILUNAR VALVE, into the AORTA,
and back to the body.
The semilunar
valves are
located
between the
ventricles and
the great
arteries.
SVC
RA
IVC
RV
Tricuspid valve
Pulmonary
artery
Pulmonary
vein
LA
LV
Pulmonary
semilunar valve
Bicuspid valve (Mitral)
Aorta
Aortic semilunar valve
Body
VALVES
CHORDAE TENDONAE
PAPILLARY MUSCLES
TRICUSPID VALVE
MITRAL VALVE (BICUSPID VALVE)
PULMONARY SEMILUNAR VALVE
AORTIC SEMILUNAR VALVE
SUMMARY OF BLOOD FLOW
Deoxy blood  sup/inf vena cava 
R atrium  tricuspid valve  R
ventricle  pulmonary semilunar
valve  pulmonary artery  lungs 
pulmonary veins  Left atrium 
mitral (bicuspid) valve  Left ventricle
 aortic semilunar valve  aorta 
rest of body.
Heart Chambers
Figure 18.5b
Heart Chambers
Figure 18.5e
Inferior View of the Heart
Figure 18.5d
Atrial
septum
Right atrium
Right
ventricle
Apex
Interventricular
septum
Left atrium
Left
ventricle
Aortic
semilunar
valve
Mitral
(bicuspid)
valve
Papillary
muscles
Cordae
tendonae
Mitral Valve Stenosis
• If there is stenosis (blockage) of the mitral valve, where
will the blood back up into?
• Answer: the pulmonary circulation.
SVC
RA
IVC
RV
Tricuspid valve
Lungs
Pulmonary
artery
Pulmonary
vein
LA
LV
Pulmonary
semilunar valve
Bicuspid valve (Mitral)
Aorta
Aortic semilunar valve
Body
HEART BEATS
The pressure of blood against blood vessel
walls is called blood pressure.
Blood pressure is recorded systole over
diastole. Normal resting blood pressure is
said to be 120/80. When blood pressure is
too high, it is called HYPERTENSION.
The sound your heart makes when it is
beating is the sound of the blood hitting the
valves after they are closed.
The heart normally beats at a rate of 60-80
beats per minute. A faster or slower heart
rate is an indication of a problem.
HEART BEATS
The left and right ventricles contract
at the same time = SYSTOLE.
When the ventricles are relaxed =
DIASTOLE.
At which stage do the atria contract?
Diastole.
HEART BEATS
SYSTOLE:
Ventricles contract
Atria relax
DIASTOLE:
Ventricles relax
Atria contract
HEART BEATS
Start of Systole: Closing of valves
(tricuspid and mitral) causes blood to
hit the valves, making a sound.
Systole of the ventricle means that
this chamber is contracting.
End of Systole: Closing of semilunar
aortic and pulmonary valves causes
blood to hit the valves, making a
sound
HEART BEATS
Lub-Dub is the sound of the blood
hitting the closed valves.
Start of Systole: Closing of the large
valves (tricuspid and mitral) = “LUB”
sound from blood hitting them.
End of Systole: Closing of semilunar
valves (aortic and pulmonary)=
“DUB” sound (“Dub”) from blood
hitting them.
Heart Sounds
Figure 18.11
Valve Problems
HEART MURMUR
If the valve leaks, it doesn’t close all
the way
“Lub-squirt”
Most murmurs are benign; fairly
common, esp. in babies and some
adults.
Valve Problems
• PROLAPSED VALVE is more serious.
• Mitral valve is most likely to prolapse because it pumped
the hardest. See how much thicker the left ventricle is?
Mitral Valve Prolapse is the most common heart valve
disorder. Might need artificial valve.
What controls the heart beat?
There is a small region in the right
atrium = SA NODE (Sino-atrium node) =
pacemaker of the heart. Its job is to
speed up or slow down the heart rate as
needed.
SA node sends an electrical signal
(action potential) to the AV NODE (atrioventricular node)  atrium contraction
pauses  signal transmitted to both
ventricles  sends the action potential
to all parts of the heart so it can
contract.
SA and AV Nodes
Conducting System
PLAY
Intrinsic Conduction System
Figure 18.12
Heart Beats
•
•
•
•
•
The heart does not need a nerve to stimulate it to contract; rather,
specialized heart cells can spontaneously start an action potential that
spreads to depolarize the rest of the cardiac muscle cells.
First the Sinoatrial (SA) node starts an action potential which causes the
atria to depolarize.
This depolarization will then reach the AV node at the bottom portion of the
right atrium and there is a delay here because these cells are so small in
diameter.
Another delay in the transmission of the depolarization at the bundle of His
(AV bundle) because these special heart cells travel through the
atrioventricular septum which is non-conductive fibrous connective tissue.
Next, the depolarizing event travels through the left and right bundle
branches, found in the interventricular septum, to finally arrive at the
Purkinje fibers in the lateral walls of the myocardium of the ventricles.
Conducting System
PLAY
Intrinsic Conduction System
Figure 18.12
Impulse Pathway
• SA node
• AV node
• Bundle of His (conduction
slows down here because this
area is fibrous connective
tissue, not muscle cells. This
gives the atria time to contract
before the ventricles
• Right and left bundle branches
on the IV septum
• Purkinje fibers on the lateral
wall of the ventricles…now
they contract
http://www.phschool.com/science/biology_place/biocoach/cardio1/electrical.html
EKG
Problems
ARRHYTHMIA
Problem with the SA or AV node 
improper heart beat.
Treatment is medicines or a
pacemaker.
Ventricular Fibrillation
FIBRILLATION is when the heart beat is not really
present…it just vibrates. A heart in fibrillation does
not contract rhythmically; it just quivers without
pumping blood.
It needs an electric shock from a defibrillator. This
machine is never used when someone’s heart is
beating with a lub-dub sound, even if it is irregular,
because it can cause the heart to stop.
Whatever caused the fibrillation in the first place is
not treated, so it may not work, but it’s worth a try!
Most large public facilities have them. There are
three on this campus. Disneyland has one every
100 yards.
THE HEART NEEDS ITS OWN
BLOOD/O2
The endocardium gets plenty of O2 from
the blood cells that touch this layer as they
travel through the heart, but the oxygen
does not diffuse all the way into the
myocardium, which is a deeper layer.
THE HEART NEEDS ITS OWN
BLOOD/O2
Therefore, the myocardium needs its
own blood supply by CORONARY
ARTERIES and VEINS.
They are on the surface of the heart,
and there are four of them.
The more you exercise, the more
branches of these arteries are formed
between themselves, and the better
the blood supply to the heart.
THE HEART NEEDS ITS OWN
BLOOD/O2
When blood vessels fuse together
where they meet it is said that they
ANASTOMOSE.
This is a safety mechanism that
allows blood to get through if one of
the vessels gets clogged.
THE HEART NEEDS ITS OWN
BLOOD/O2
If one of the four coronary arteries
becomes clogged, ISCHEMIA (lack of
oxygen) to part of the heart muscle will
result.
This is a painful condition, and the pain of it
is called ANGINA (heart pain).
If nothing is done immediately to increase
the blood flow, the myocardial tissue can
die; this condition is called a HEART
ATTACK.
Coronary Bypass
People who have an angina attack can
take nitroglycerine as a tablet under the
tongue that dissolves quickly.
This medicine will dilate the blood vessels.
Weird ER Story
A 28-year old male was brought into
the ER after an attempted suicide.
The man had swallowed several
nitroglycerine pills and a fifth of
vodka.
When asked about the bruises about
his head and chest he said that they
were from him ramming himself into
the wall in an attempt to make the
nitroglycerine explode.
Coronary Bypass
When a person has their first angina
attack, the doctor will order an
ANGIOGRAM to look for a narrowing
in an artery, especially in one of the
coronary arteries.
Coronary Bypass
If a coronary artery is found to have a
severe blockage, they can do a
CORONARY BYPASS.
In this procedure, the doctor takes
another blood vessel graft (from the
greater saphenous vein in the thigh)
and sews it in around the blockage.
For double or triple bypasses, that’s
how many vessels are affected.
Blood Supply to the Heart
Figure 18.14
R. Coronary
artery
Anterior
interventricular
artery (posterior
interventricular
artery is on the
back side)
L. Coronary
artery
Circumflex
artery
TERMS
ANGINA: heart pain, usually
caused from not enough oxygen to
the myocardium (ischemia)
ISCHEMIA: lack of blood/oxygen
MYOCARDIAL INFARCTION: heart
attack from blood clot in coronary
artery, causing ischemia, which
causes angina
HEART ATTACK
Not enough blood to the heart’s
myocardium layer  MILD ISCHEMIA 
severe pain: ANGINA (angina pectoris)
Treatment is nitroglycerine to open arteries
Complete blockage  not enough O2 to
that area = SEVERE ISCHEMIA  that
part of heart muscle dies = MYOCARDIAL
INFARCTION.
Heart muscle never regenerates. If a large
area dies, person will die.
HEART ATTACK
What are symptoms of a heart attack? Chest pain,
pain down left arm, shortness of breath, nausea,
tight pressure in chest. A common symptom is
death. 50% of first heart attacks are fatal within 2
hours. If a person receives good treatment in the
first 2 hours, they are more likely to survive. About
¾ million people die each year from heart attacks.
A drug that can stop heart attacks in progress by
dissolving clots is t-PA (also used to prevent clots
that cause strokes)
Angioplasty is a surgical procedure to clean out a
clogged artery.
A beta blocker is a drug that slows down the heart
rate
Aspirin reduces blood clot formation
Nitroglycerine dilates the coronary arteries so
more blood can get in.
Fun Fact
If a person takes an aspirin once a
day to prevent clots or a heart attack,
they should take it at NIGHT.
Aspirin has a half life of 24 hours, so
its effect is strongest in the morning.
Most heart attacks occur in the
morning!
Bayer has new Quick Release
crystals that dissolve faster in
your mouth.
Heart Medicines
t-PA (dissolves blood clots)
Beta-blockers (slows heart rate)
Aspirin (prevents blood clots)
Nitroglycerine (dilates coronary
arteries)
CIRCULATORY DISEASE
CONDITIONS
The leading cause of untimely death in the
Western countries of the world is
cardiovascular disease.
There are several hereditary factors that
influence whether a person will get
cardiovascular disease:
1. family history of heart attack
2. gender (males are high risk)
3. race/ethnicity (African Americans high
risk)
CIRCULATORY DISEASE
CONDITIONS
Whether or not you have a hereditary
factor, there are some things you can do to
prevent heart disease with diet and
exercise. Included in this is knowing your
cholesterol level, lowering your LDL intake,
use olive and canola oil rather than
butter/cream.
Some studies also suggest that antioxidant
vitamins (A, E, and C) may help, but
remember that too much vitamin A and E
cause a lot more harm to the liver than
good to the circulation.
Causes of High Blood
Pressure
ARTERIOSCLEROSIS (hardening of the arteries):
caused by a build-up of calcium deposits in the
artery wall; artery cannot expand with blood
surges. Tends to be hereditary.
The blood vessel becomes hard like a rock;
it can’t expand or contract, causes increase
in blood pressure.
Diet and exercise don’t help this much.
Both arteriosclerosis and atherosclerosis
cause high blood pressure.
Areteriosclerosis
Causes of High Blood
Pressure
ATHEROSCLEROSIS (The most
common form of arteriosclerosis; a
build-up of fat in the arteries): caused
from eating fatty food  narrowing of
artery  Spasm shut or blood clot.
Atherosclerosis
EMBOLISM
When fat builds up in a lump in one
place, it is called a PLAQUE. It
causes the lumen to narrow,
restricting blood flow.
If this fatty plaque breaks off and
travels in the bloodstream, it is now
called an EMBOLISM. An embolism
can also be made of blood instead of
fat.
How a thrombus becomes
embolism
If a platelet catches on a piece of this fat, it
can start a blood clot (thrombus).
If a piece of the clot (thrombus) breaks
off and enters the circulation, it is now
called an embolism, it can lodge in a
smaller blood vessel and block the oxygen
to all the tissue past that point, and the
tissue dies.
A thrombus can become an
embolism
A thrombus is made of BLOOD. It is a
blood clot that is located on the inside wall
of a blood vessel (usually a vein but not
always) and it has not moved anywhere
(yet).
An embolism can be made of FAT or
BLOOD. It is either a build up of fat in a
vessel (usually an artery but not always)
that has broken off a piece or a blood clot
(usually in a vein but not always) that has
broken off a piece. It travels and gets
lodged in a smaller vessel somewhere.
Blockage of blood vessel
If the embolism lodges in the coronary
arteries  myocardial infarct (Heart
attack).
If the embolism lodges in an artery in
the brain  stroke
If the embolism lodges in the lungs
 pulmonary embolism
Pulmonary Embolism
ANGIOGRAM
An ANGIOGRAM is a procedure to
inject dye into the arteries and x-ray
to see if there is narrowing (sclerosis)
of a vessel. This can be done
anywhere in the body that is of
interest, but frequently it is done to
check the coronary arteries.
Angiogram
ANGIOGRAM
If an artery is too narrow, an
ANGIOPLASTY can be performed to
open it up. This involves sticking a
balloon into the artery and inflating it,
causing the vessel to enlarge a little
to increase blood flow. This can be
done anywhere in the body, but is
frequently done in coronary arteries.
Angioplasty
CORONARY BYPASS
For a coronary artery that has become
extremely narrow from plaques, you can do
a CORONARY BYPASS.
Take another blood vessel graft (superficial
vein from thigh) and go around the
blockage. For double or triple bypasses,
that’s how many vessels are affected.
People who exercise have the same
number of heart attacks as those who
don’t, but they tend to survive them.
VENTRICULAR FIBRILLATION
Even a small clot can be a problem. If
it happens to enter the interior of the
heart and lodge in the wall of the
atrium, it can block the conduction of
the signal of the AV node 
VENTRICULAR FIBRILLATION.
ANEURYSM
High blood pressure is due to high
pressure of blood against the walls of the
blood vessels; the blood vessels
compensate by developing a thicker wall.
The vessels can no longer expand during
systole, so the vessel gets thicker and
thicker, and the blood pressure goes up
more.
If the blood pressure gets too high, an
ANEURYSM can form, which is a
weakening in the wall of the blood vessel,
causing it to expand like a balloon.
ANEURYSM
Thus, an aneurysm is a sac-like
outpouching of an artery.
If it ruptures, it’s very dangerous. The
aorta is the first artery that leaves the
heart. It is under high pressure, so it
is susceptible to rupture; you’ll be
dead in three heart beats.
Can also get aneurysms in the brain
that cause stroke. Aneurysms have
no symptoms.
Predictors of Heart Attack
High Blood Pressure
High Cholesterol
Large Waist Size
Predictors of Heart Attack
Normal blood pressure is 120/80.
Pre-hypertension is 120 to 139
(systolic) and/or 80 to 89 (diastolic).
Hypertension – also known as high
blood pressure -- is 140 or higher
(systolic) and 90 or higher (diastolic).
One in three adults in the U.S. has
high blood pressure or prehypertension.
Predictors of Heart Attack:
Cholesterol levels you DON’T want
Total cholesterol higher than of 200 mg/dL.
HDL ("good" cholesterol) lower than 50
mg/dL (females) or 40 mg/dL (males).
LDL (“bad” cholesterol) higher than 100
Unless you have other major risk factors, like
diabetes, you want your LDL closer to 70.
Triglycerides of greater than 150 mg/dL.
Predictors of Heart Attack
FEMALES: waist size more than 35 inches
MALES: waist size more than 40 inches
Measure around your belly button.
If patients lose even 1 inch off their waist,
there are improvements in all the other
heart health numbers
If they gain even 1 inch, there is a
worsening in those numbers. It's a much
better indicator of heart health than weight.
Other Heart Conditions
Congestive Heart failure
Progressive weakening of the heart
Blood backs up into lungs (may cough
up blood)
Cannot meet the body’s demands for
oxygenated blood
Hypertrophic cardiomyopathy
Congenital condition where the walls of
the left ventricle are so thick that the
lumen is too small to hold much blood.
Disorders of Conduction
Ventricular fibrillation
Rapid, random firing of electrical
impulses in the ventricles of the AV node
Atrial fibrillation
Rapid, random firing of electrical
impulses of the SA node
Most Common Heart Problems
ATHEROSCLEROSIS
VENTRICULAR FIBRILLATION
Congestive heart failure
Hypertrophic cardiomyopathy
EMBRYONIC DEVELOPMENT OF
THE HEART
The heart is the most common site for
congenital defects (those one is born
with).
During fetal life, the mother provides
the oxygen and nutrients through the
placenta. If there is a problem with the
baby’s heart, it is not a problem until
birth, although it can be detected by
ultrasound.
EMBRYONIC DEVELOPMENT OF
THE HEART
• The earliest heart chambers
Figure 18.16a, b
The Heart Throughout Life
Figure 18.16c–e
EMBRYONIC DEVELOPMENT OF
THE HEART
At 28 days (two weeks after a woman
misses her period), the human heart
first starts to beat and pump blood in
the embryo (at the start of the fourth
week).
You have to stop smoking and
drinking before you get pregnant. By
the time you know you’re pregnant,
it’s too late for the baby’s heart.
Fetal Heart
Where is the fetus getting the oxygen
during the nine months in the womb?
The mother, not the lungs.
So there’s no sense in sending half of
the body’s blood to the lungs for
oxygen.
FORAMEN OVALE
The lung tissue needs some oxygenated blood,
but only a little. Therefore, there is an opening
from the right to the left atrium called the
FORAMEN OVALE which shunts blood from the
right to the left side of the heart to bypass the
lungs.
There is a foramen ovale in the skull and another
one in the heart. The foramen ovale in the heart
normally closes shortly after birth, and is then
called the FOSSA OVALIS.
A ‘blue baby” has low oxygen levels in the blood
that may be due to failure of the foramen ovale to
close at birth.
Foramen Ovale
DUCTUS ARTERIOSIS
Another shunt: between the pulmonary
artery and the aortic arch so that most of
the blood bypasses the immature lungs
Therefore, there are two shunts to take
blood away from the lungs. When the
ductus arteriosis closes off at birth, it is
called the ligametum arteriosum
Figure 18.5b
Changes at Birth
At birth, there is an immediate
change. Half of the blood needs to go
to the lungs.
At the first breath, a flap closes over
the foramen ovale, and a muscle
around the ductus arteriosis
constricts, causing instant closing,
and seals shut permanently.
Patent Foramen Ovale
When a baby has not started walking, it
doesn’t need as much oxygen, so a patent
(open) foramen ovale might not be noticed
until they start to walk and run at age 2-3.
However, every time the baby cries, it
might turn blue.
A patent foramen ovale can be surgically
closed by going through the blood vessels
without cutting into the heart tissue.
A patent foramen ovale in an adult is just a
tiny opening and can be heard as a heart
murmur.
Heart Deformities
You can also have a patent ductus
arteriosis.
More significant problems:
interventricular septal defect (between
right and left ventricle).
Requires open heart surgery.
Congenital Heart Defects
Figure 18.17a, b
Artificial Heart
• If heart is
totally
deformed,
need
transplant.
The Heart in Adulthood and Old Age
Age-related changes
Hardening and thickening of valve cusps
Decline in cardiac reserve
Sympathetic control over heart is less
efficient
Less severe in the physically active
Fibrosis of cardiac muscle tissue
Lowers the amount of blood the heart can
pump