Download The Heart

The Heart
The Heart
Heart pumps over 1 million gallons per year
 Over 60,000 miles of blood vessels

I. Layers of Heart Wall
A.
Pericardium
1.
B.
Myocardium
1.
C.
protects and anchors
the heart, prevents
overstretching
cardiac muscle
layer is the bulk of
the heart
Endocardium
1.
chamber lining &
valves
II. Structures of the Heart
Left common carrotid
Brachiocephalic trunk
aorta
Left subclavian artery
left pulmonary artery
Superior vena cava
Mitral/bicuspid
pulmonary semi-lunar
Left atrium
Right atrium
Right pulmonary vein
Aortic semi-lunar
Chordae tendinae
myocardium
tricuspid
Papillary muscle
Left
ventricle
inferior vena cava
Right
ventricle
Interventricular septum
Descending aorta
III. Blood Circulation
Two closed circuits, the systemic and pulmonic
B. Pulmonary circulation
A.
1.
2.
3.
4.
Right atrium pumps blood through the tricuspid valve to
the right ventricle
Right ventricle pumps blood through the pulmonary semilunar valve to pulmonary trunk
pulmonary trunk branches into left and right pulmonary
arteries
Pulmonary arteries carry blood to lungs for exchange of
gases

5.
Which gases and in what direction?
Oxygenated blood returns to the heart through the
pulmonary veins into the left ventricle
Blood Circulation (con’t)
C.
Systemic circulation
1.
Left atrium pumps blood though the mitral valve
(bicuspid) to the left ventricle

2.
left ventricle pumps oxygenated blood through the aortic
semi-lunar valve into aorta

3.
4.
5.
6.
7.
Why is this valve replaced the most often?
Why is the myocardium of this chamber the thickest?
Aorta branches into many arteries that travel to organs
Arteries branch into many arterioles in tissue.
Arterioles branch into thin-walled capillaries for exchange
of gases and nutrients
Deoxygenated blood begins its return in venules
Venules merge into veins and return to right atrium via
the vena cavas
IV. Blood Flow Off Descending Aorta
A.
Common carotid artery (left)
First branch coming off of the aorta and it
carries blood to head and brain
2. Returns through jugular veins to superior
vena cava
1.
B.
Left & right Subclavian arteries carries
blood to the arms and the subclavian
veins return blood to the superior vena
cava.
Blood flow off Descending Aorta (2)
C.
D.
E.
Celiac artery carries blood to stomach,
spleen and liver
Portal vein leads to the liver and leaves
through the hepatic (liver) vein to inferior
vena cava.
Superior mesenteric artery carries blood to
the small intestine, which in turn connects
to the portal vein.
a)
This way all materials entering the blood stream
from the digestive tract are sent directly to the liver
for detoxification.
Blood flow off Descending Aorta (3)
F.
Inferior mesenteric artery leads to large
intestine (and small, but mostly large)
Large intestine leads to internal iliac vein
(hypogastric) that connects to the
inferior vena cava
G. The Iliac arteries branches to supply blood
1.
to reproductive and excretory organs,
as well as the legs
1.
Blood returns through iliac veins to
inferior vena cava
HEART QUESTIONS

How many times will your heart beat in
80 years?

How much blood is pumped with each
heart beat?
V. Cardiac Cycle
A.
Atrial diastole
both atria fill with blood
atrioventricular valves are open and the
semilunar valves are closed
3. 75% of ventricular filling occurs now
4. lasts about 0.7 seconds
1.
2.
B.
Atrial systole
atria contract forcing the remaining 25% of
the blood into the ventricles
2. lasts about 0.1 seconds
1.
Cardiac Cycle (2)
C.
Ventricular diastole
ventricles are relaxing
2. lasts about 0.5 seconds
1.
D.
Ventricular systole
ventricles are contracting
2. blood is being forced into the aorta and
pulmonary arteries.
3. the semilunar valves are open and the
atrioventricular valves are closed.
4. lasts about 0.3 seconds
1.
VI. Cardiac Conduction System
A.
B.
C.
Impulse originates in sinoatrial node (SA
node or pacemaker) which is located in the
superior region of the right atrium.
Impulse spreads across both atria which
causes them to contract at the same time.
The impulse reaches atrioventricular node
(AV node) located at the top of the right
ventricle.
Cardiac Conduction System (con’t)
D.
E.
F.
From the AV node the impulse passes
through the atrioventricular bundle
node to (Bundle of His).
The Bundle of His branches off into
right and left bundle branches.
The impulse now flows through the
many branches of the Purkinje fibers
which pass deep into the ventricular
myocardium.
Pacemaker
Bundle of His
AV node
Purkinje fibers
VII. Electrocardiogram-ECG or EKG
Action potentials of all
active cells can be
detected and recorded
B. The machine amplifies
electrical impulses
generated by your
muscles.
C. 4 basic parts to
analyze:
A.
1.
2.
3.
4.
P wave
P to Q interval
QRS complex
T wave
VIII. ECG Analysis
Parameters
A.
Horizontal Axis
1.
a)
b)
Measures time of
duration.
Each box or mm =
0.04 seconds
2. Vertical Axis
a) Measures voltage or
amplitude
b) Each box or mm = 0.1
mV
P-Wave
1.
2.
3.
Depolarization of the
atria (atrial systole)
Amplitude of P-Wave
should be less than
0.2 mV to 0.3 mV
Duration of P-Wave
should be less than
0.11 seconds
QRS Complex
Atria repolarization (atrial
diastole)
2.
Ventricle depolarization
(ventricular systole)
3.
Amplitude should be greater
than 0.5 mV in leads 1, 2, or 3
1. Measured from tip of R to
bottom of S
4.
Duration should be less than
0.12 secs.
1.
T-Wave (isoelectric)
1.
2.
Repolarization of ventricles
(ventricular diastole)
Amplitude should be less
than 0.5 and greater than
1/10 of R wave for that
segment.
a)
3.
4.
T-wave should be on the
isoelectric line
Duration not a concern
T-wave should be in the
same direction as the Rwave
P-Q Interval
Measured from
beginning of P to
beginning of Q.
2. Between 0.12 and
0.2 second
duration.
3. Too long indicates
AV block.
1.
ST Segment
1.
Amplitude should be
isoelectric
a)
b)
2.
If depressed more
than 2 mm indicates
ischemic heart.
Most often caused by
atherosclerosis.
Duration should be
between 0.13 - 0.16
sec.
Heart Rate
1.
HR= 60/(R to R Interval in seconds)
Cardiac
Cycle
Regulation of
Heart Rate
I. Cardiac Output (CO)
The amount of blood the heart
pumps in 1 minute.
B. CO = stroke volume (SV) x heart
rate (HR)
A.
1.
example: 70 mL of blood/beat x 70
beats/min. = 4900 mL/min.
II. Influences on Stroke Volume
A.
Preload (affect of stretching heart muscle)
1. Frank-Starling Law of Heart
a)
b)
c)
d)
B.
C.
The longer the filling time, the greater the stretch of cardiac
muscle
more muscle is stretched, greater force of contraction
This explains why athletes have lower resting heart rates but the
same cardiac output
more blood more force of contraction results
Contractility
1. autonomic nerves, hormones, Ca+2 or K+ levels
Afterload
1. amount of pressure created by the blood in the way
2. high blood pressure creates high afterload
III. Control Centers for Heart Rate
A.
Two centers found in the medulla
1. Cardioacceleratory center
a) has a sympathetic nerve
(cardioaccelerator nerve) that
connects to the SA node of the heart.
2. Cardioinhibitory center
a) has a parasympathetic nerve (vagus
nerve) that connects to the SA node
of the heart.
IV. Factors that effect heart rate
A.
Blood Pressure (BP)
1.
Carotid Sinus Reflex:
a) As the BP in the carotid sinus rises the walls of the
carotid sinuses stretch (baroreceptors)
b) Stretching increases stimulation of the glossopharyngeal
nerve, which leads to the cardioinhibitory center in the
medulla.
c) The inhibitory center stimulates the Vagus nerve which
slows down the heart rate
d) Therefore a drop in HR, produced a drop in CO, which
produced a drop in blood pressure, that reduced the
amount of stretch in the carotid sinus.
e) What happens if there is a drop in blood pressure in the
carotid sinus?
Factors that effect heart rate (con’t)
2.
Aortic reflex (regulates BP to rest of
body)
Right Atrial (Bainbridge) reflex
b) There are baroreceptors located in the
right atrium and in the superior and inferior
vena cavas.
c) When these are stimulated heart rate
increases.
 Why increase heart rate instead of
decrease?
a)
Factors that effect heart rate (con’t)
B.
Chemical Factors
1.
CO2
increases heart rate
2. Adrenaline (epinephrine)
a) increases heart rate
3. Ca 2+
a) increases heart rate
4. Na+ and K+
a) lower heart rate
a)
Factors that effect heart rate (con’t)
C.
Other factors
1. Sex
a) females have higher heart rates
2. Age
a) older-slower
3. Exercise
a) increase
b) person who exercises regularly has a lower
resting heart rate than one who doesn't - called
Bradycardia
4. Temperature
a) Higher temperature, higher heart rate
Cardiovascular Disease
(CVD)

In the U.S.—1 million deaths/year
I. Coronary heart disease (56%)
A.
Cause
Slow build up of fatty plaque
(atherosclerosis) along the walls of the
coronary blood vessels which reduces
blood flow to heart
2. The drop in O2 levels (ischemia)
causes a angina which could lead to
myocardial infarction.
1.
B. Diagnosis
1.
Outward symptoms of a heart attack:
a)
b)
c)
d)
e)
f)
g)
pain in chest and left arm
cyanosis of lips
nausea
dizziness
shortness of breath
cold sweat
denial
Diagnosis (con’t)
Exercise ECG
a)
ST Depression
b)
Problems with PR interval
3.
Angiogram
a)
A catheter is inserted into femoral artery of
pelvis and worked into the aorta.
b)
Then dye is injected through catheter.
c)
A fluoroscope will show the dye pathway.
d)
Any narrowing or blockages will show up
on the fluoroscope.
2.
C. Treatment
Bypass surgery
a)
remove a vein from the leg and use it to
bypass a blockage in heart vessel
b)
stop heart and put on a heart lung machine
2.
Angioplasty (see angiogram)
a)
Catheter with specialized tip is positioned
where the coronary artery is narrowed or
blocked.
b)
Use syringe to blow up catheter’s balloon
(fig. 20-14, page 599).
c)
Balloon presses the plaque up against the
walls of the vessel.
1.
By-pass Graft
Coronary
Angioplasty
CVD
Stroke 20%
II.
A.
B.
The interruption of blood flow to the
brain
Causes
1.
2.
3.
thrombus vs. embolus
atherosclerosis (has no symptoms)
aneurysm-broken blood vessel
Stent in an Artery

Maintains patency of blood vessel
CVD
Hypertension 7%
III.
A.
B.
Chronic high blood pressure
More common in black males than white.
Myocardial degeneration 5%
IV.
A.
Heart muscle degenerates
Arteriosclerosis 4%
V.
A.
Hardening of the arteries
Rheumatic fever 2%
VI.
A.
Childhood disease that damages heart valves
VII. Risk Factors associated with
Cardiovascular Disease
A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
age
sex
genetics
diets high in fat (hyperlipidemia)
high blood pressure
smoking
stress
alcohol
obesity
inactivity
VIII. First Heart Attack Risk Test
A.
Age:
1.
2.
Men: 0 pts = Less than 35, 1 pt = 35 to39, 2 pts
= 40 to 48, 3 pts = 49 to 53, 4 pts = 54+.
Women: 0 pts = Less than 42, 1 pt = 43 to 45, 2
pts = 46 to 54, 3 pts = 55 to 73, 4 pts = 74+.
Family History: 2 pts if family has a history
(parents and/or grandparents) of heart disease
or heart attack before age 60.
C. Inactivity: 1 pt if you rarely exercise or do
anything physically demanding.
D. Weight: 1 pt if you are more than 20 pounds
overweight.
B.
First Heart Attack Risk Test (con’t)
Inactivity: 1 pt if you rarely exercise or do
anything physically demanding.
F. Weight: 1 pt if you are more than 20
pounds overweight.
G. Smoker: 1 pts if you smoke
H. Diabetes: 1 pt if you are male, 2 pts if
your are female.
I.
Total Cholesterol Level: 0 pts if you are
less than 240 mg/dl, 1 pt if you are 240315 mg/dl and 2pts if you are greater than
315 mg/dl.
E.
First Heart Attack Risk Test (con’t)
J.
K.
L.
HDL Level: 2 pts if you are under 30 mg/dl, 1 pt
if you are 30-38 mg/dl or 1 pt if you are over 60
mg/dl, and 0 pts if you are 38-59 mg/dl.
Blood Pressure (Systolic): 0 pts if less than 140
mmhg, 1 pt if 140-170 mm/hg and 2 pts if greater
than 170 mmhg.
Scoring the test: Any value above four represents
an above average risk; the higher the number, the
greater the risk.
IX. Benefits of Aerobic
Exercise
A.
B.
C.
D.
E.
Normalizes BP
Bradycardia
1. heart pumps more blood per beat
2. more efficient
Increases the number of RBC's
Increases caloric output
Decreases LDL's and increases HDL's
1. High density lipoproteins (HDL's) contain more
protein than fat and HDL's are able to remove
low density lipoproteins (LDL's) from the blood
stream
2. LDL's have a higher proportion of fat and tend
to accumulate along the walls of the arteries of
the body, and heart in cerebral arteries
X. Designing A Good Exercise
Program
A.
Correct intensity as measured by heart rate
1.
2.
Heart must work
athlete 80-90% of the max. HR
normal 70-80% of the max. HR
older
60-70% of the max. HR
Maximum HR= 220 — age
e.g. a normal person 40 years of age
(220-40) x 70%
180 x 0.7 =126.0 beats/min.
180 x 0.8=144 beats/min.
Designing A Good Exercise Program
(con’t)
B.
Correct duration
1.
C.
20 minutes or longer at target
heart rate
Frequency
1.
3-4 times a week or every
other day