Transcript Cardiovascular powerpoint

Flashcard Warm-up #25 and 26
 Heart
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Atria
(auricles)
 Heart
There are two in a
mammalian heart
The receiving
chambers (space)
located superiorly
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Ventricles
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There are two in a
mammalian heart
Known as the
pumping chambers
located inferiorly
The Cardiovascular System
I. The Heart (the pump of the station)
A. Structure and location of the heart
1. Apex of the heart is pointed toward left
hip and located at the 5th intercostals
space. The ventricles are the two lower
muscular chambers of the heart.
2. Base of the heart is located at the 2nd rib
and is the area where the large vessels
enter and leave the heart and the location
of the two sac like atria chambers.
3. The heart is made up of 3 layers of cardiac
muscle:
a. Epicardium – also called the visceral
pericardium. Helps to protect and anchor
the heart to sternum and diaphragm.
b. Myocardium – cardiac muscle arranged like
rings around the heart. Layer that
contracts. There is a dense fibrous layer
deep to the cardiac muscle.
c. Endocardium – Thin sheet of endothelium
that is continuous with the vessels that enter
and leave the heart.
d. The parietal pericardium is
outside/superficial to the epicardium and
secretes the serous fluid that lubricates the
cardiac sac so the heart can beat in an almost
frictionless environment.
5. Heart internal anatomy
6. Importance of valves
a. Valves prevent backflow of blood through
the heart.
b. Two atrioventricular valves (bicuspid and
tricuspid) are anchored to the ventricles by
the chorda tendineae (heart strings). The
system is a pressurized system.
B.
1. Blood passively fills the chamber, flaps
hang down into the ventricles
2. When the ventricles begin to contract,
the pressure increases which forces the
flaps of the valves closed. The chordae
tenineae prevent the flaps from opening
back up into the atria.
Valves and heart sounds
C. The two semilunar valves (pulmonary and
aortic) have 3 cusps that fit tightly together.
When the ventricles contract the force of
the contractions open the valves into the
pulmonary vein or aorta as the blood
rushes into the vessel. As the ventricle
relaxes the cusps come back together.
Heart in action!
d. The AV valves and
semilunar valves open and
close at different time so it is
possible to detect problems
with individual valves by
placing the stethoscope at
different points on the chest.
e. When valves do not work
properly, the heart is forced to
work harder to pump blood,
which can weaken the heart
over time. Valves can be
replaced by pig or synthetic
valves.
Heart sounds
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http://depts.washington.edu/physdx/heart/de
mo.html
Flashcard Warm-up #27
 Pathway
of Blood through the heart
Trace the pathway of the blood through all heart
structures including valves and vessels
 Use the video clip and the notes we took yesterday
to help!
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B. Functioning of the heart
1. Pathway of blood through the heart and body
Blood Flow Through Your Heart and Lungs
2. The heart is supplied with
nutrients and gases by the
cardiac vessels (the presence of
the blood in the heart does not
accomplish this). These are
called coronary arteries and
coronary veins.
a. The blood from the veins
empties into the coronary sinus
in the right atrium.
b. When these vessels become
clogged or blocked this can
cause chest pain, angina, and if
ignored can lead to a cardiac
infarction (tissue death from
heart attack) when the cells are
deprived of oxygen and nutrients.
Heart attack animations
3. Cardiac Cycle
a. Electrical system of the
heart determines how often
the heart beats and controls
the contraction of the heart.
1. Contractions occur
spontaneously but must be
regulated so that the
chambers of the heart beat in
a coordinated way. It is
regulated by two systems:
2. Autonomic nervous
system controls the increase
or decrease of heart rate.
Diastole means relaxation and Systole means contraction**
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. Intrinsic system within
the heart tissue which
begins at the SA
(sinoatrial node) in the
right atria, the signal is
then carried to the
other atria and the AV
(atrioventricular node)
which carries the
impulse to the bottom
of the ventricles via the
bundle of His and the
purkinje fibers.
2. This electrical system can be measured by an
electrocardiogram (ECG or EKG).
Diastole means
relaxation and
Systole means
contraction**
C. Cardiac Output and the health of the heart
1. Cardiac Output (CO) is a function of stroke
volume (volume of blood pumped out with each
contraction and heart rate (number of beats per
minute) CO = SV · HR , This stroke volume (SV), times the
number of beats per minute (heart rate, HR), equals the cardiac
output (CO).
2. Factors affecting cardiac output and effects:
Venous return – amount of blood returning to
the heart and enlarging the ventricles. The
larger the venous return, the more stretched
the cells the stronger the contraction.
Exercise can increase venous return with the
enhanced squeezing action of the skeletal
muscles returning blood to the heart. Rapid
heart rate or severe blood loss will decrease
venous return.
b. Heart rate changes – HR can increase with
the loss of blood or can be altered by other
factors such as nervous stimulation
(sympathetic nerves to speed up),
hormones (epinephrine and thyroxine can
increase), and changes in ions (lower
potassium causes irregular heartbeat).
c. Age, gender, body fitness and body
temperature.
1. Gender – females (72-80 avg. HR),
males (64-72 avg. HR)
2. As you age your heart rate decreases, it
is the fastest when you are a fetus (140 to
160)
3. The colder you are the slower your heart
rate.
D. Cardiac congestion – congestive heart
failure
1. Caused by weakening of the heart
muscle (clogging of cardiac vessels),
heart attack, or high blood pressure.
2. Failure of left side of the heart
causes pulmonary congestion – build
up of fluid in the lungs, person can
“drown” if not treated.
3. Failure of the right side of the heart
causes peripheral congestion – build up
of fluid in the extremities causing
edema.
FDA Heart Health Online - Congestive
Heart Failure
IV. The Vessels – Highway system
A. Types of vessels
1. Arteries – vessels carrying
blood away from the heart.
Not always oxygenated
blood. Largest and most
muscular of the vessels,
contain all three tunic layers.
2. Arterioles – smaller arteries
that feed the capillaries.
3. Capillaries – smallest of the
vessels and the site of
exchange between blood
vessels and body tissues. Are
only one cell layer thick.
Exchange is based on osmotic pressure and
blood pressure between body tissues.
IV. The Vessels – Highway system
4. Venules – drain the capillary bed and lead to
veins.
5. Veins – Carry blood back toward the heart. Vessel
has a reduced smooth muscle layer (smaller and less
muscular).
i.Adaptations to help return blood to the
heart are valves within the vein to prevent
back flow, skeletal muscle contractions
pushing blood back up legs and arms, and
respiratory pump to push blood through
the trunk.
ii.Varicose veins occur when the vein
becomes distended and the valves stop
functioning. Blood can pool and clot in
these areas, which if the clot moves can
be very dangerous.
Location of specific vessels: Arteries
Location of specific vessels: Veins
D. Physiology of Circulation
1. Arterial pulse is felt in several
places in the body. The pressure
you feel when you palpate these
areas is the expansion and recoil
of the arteries following each heart
contraction. These are also the
locations of pressure points, areas
to apply pressure if person is
hemorrhaging.
2. Blood pressure measures the
pressure the blood exerts on the
wall of the artery following each
heart contraction. The closer
you are to the heart, the higher
the pressure will be.
i.Pressure is needed to propel the blood
through the vessel system of the body
and the elasticity of the arteries is very
important to maintaining blood pressure.
ii. Pressure is taken by measuring:
Systolic pressure – ventricular
contraction, top number, recorded
when sounds are first heard in the
stethoscope.
Diastolic pressure – ventricular
relaxation, bottom number, recorded
when the sounds can not be heard in
the stethoscope.
iii. Factors that affect blood
pressure/peripheral resistance
1. If arteries are narrowed this will
increase blood pressure
a. Disease: atherosclerosis
b. Chemicals: nicotine
(vasoconstrictor)
c. Diet: high salt, fat and
cholesterol
2. Kidney’s play a major role in
regulating blood pressure by
stimulating the excretion of more
water in the urine or less water.
3. Hypotension (lower than avg. blood
pressure) can be age related as
blood pools in the extremities and
when going from sitting to standing
the BP drops suddenly. Can also be
caused by major blood loss.
Cardiovascular System
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Blood Reading Guide
Pgs. 10A and B
Silent Killer Series Notes
Pathway of blood Lab