Download Right atrium

CIRCULATORY SYSTEM
OBJECTIVES
Discuss the location, size and position
of the heart
Identify the heart chambers, sounds,
and valves
Trace blood through the heart and
compare the functions of the heart
chambers
OBJECTIVES
List the anatomical components of the
heart conduction system
Discuss features of a normal
electrocardiogram
Explain blood vessel structure and
function relationships
Trace path of blood through the systemic,
pulmonary, hepatic portal, and fetal
systems
OBJECTIVES
Identify and discuss the primary factors
involved in the generation and regulation
of blood pressure and explain the
relationships between these factors
Recognize, define, spell, and pronounce
the terms related to pathology, diagnostic,
and treatment procedures of the system
HEART
Location: between the lungs in the lower
portion of the mediastinum
Size: triangular shaped; roughly the size
of a closed fist
Position: in the thoracic cavity between the
sternum in front and the bodies of
the thoracic vertebrae behind
THE HEART
HEART CHAMBER ANATOMY
Divided into left and right sides
Each side is subdivided to form
four chambers
Atria
Ventricles
Septum separates the chambers
ATRIA
Two upper chambers
Receiving chambers
All blood vessels coming into
the heart enter here
A
T
R
I
A
VENTRICLES
Pumping chambers of the heart
Walls are thicker than walls of the atria
V
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T
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L
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HEART VALVES
Control the flow of blood through the heart
If a valve does not function properly, the
heart cannot pump blood effectively to the
body
Four valves:
Tricuspid
Pulmonary semilunar
Mitral/Bicuspid
Aortic semilunar
TRICUSPID
VALVE
Controls the
opening
between the
right atrium
and right
ventricle
PULMONARY
SEMILUNAR
VALVE
Located between
the right ventricle
and the pulmonary
artery
MITRAL/
BICUSPID
VALVE
Located between
the left atrium and
left ventricle
AORTIC
SEMILUNAR
VALVE
Located between
the left ventricle
and the aorta
VALVE FACTOIDS
•Atrioventricular valves (AV): prevent
backflow of blood into the atria when
the ventricles contract
• Chordae Tendineae: attach the AV valves
to the walls of the heart
V
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N
T
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Questions???????
Where is the tricuspid valve located?
Where is the pulmonary semilunar
valve located?
What is the function of Chorde tendineae?
SEPTUMS
Interatrial septum: separates the right
atrium from the left atrium
Interventricular septum: separates the
right ventricle from the left ventricle
NOTE: the narrow tip of the heart
is called the apex
THE PERICARDIUM
Double-walled membranous sac that
encloses the heart
Pericardial fluid is between the layers and
prevents friction when the heart beats
Pericarditis: inflammation of the
pericardium
WALLS OF THE HEART
Epicardium: external layer of the heart
and also part of the inner layer of the
pericardial sac
Myocardium: the middle thickest layer
that consists of the cardiac muscle
Endocardium: lining of the heart; forms
the inner surface that comes in direct
contact with blood being pumped through
the heart
WALLS
OF THE
HEART
HEART ACTION
Muscular pumping device for distributing
blood to all parts of the body
Contraction of the heart is called……..
Systole
Relaxation of the heart is called………
Diastole
CONTRACTION
Atrial systole: atria contract, forcing
blood into the ventricles
Once the ventricles are filled………
Ventricular systole: ventricles contract,
forcing blood from the ventricles into
the body
BLOOD FLOW THROUGH THE HEART
Right atrium (RA)
receives oxygen-poor blood through
the superior and inferior vena cava
Tricuspid
Valve
Right ventricle (RV) pumps oxygen-poor
blood through the pulmonary semilunar
valve and into the pulmonary artery,
Which carries it to the lungs
BLOOD FLOW CONTINUED
The left atrium (LA) receives oxygen-rich (oxygenated)
blood from the lungs through the four pulmonary
veins.
The blood flows out of the LA, through the…………..
Mitral
Valve
The left ventricle (LV) receives oxygen-rich blood from
the left atrium. Blood flows out of the LV through the
aortic semilunar valve and into the aorta, which
carries it to all parts of the body, except the lungs
NOTE
• The PULMONARY ARTERY is the only
artery that carries unoxygenated blood
• The PULMONARY VEIN is the only vein
that carries oxygenated blood
NOTE
SYSTEMIC CIRCULATION
Includes blood flow to all parts of the
body except the lungs
Oxygen-rich blood flows from the left
ventricle into arterial circulation
Oxygen-poor blood flows out of the
heart and flows into the right atrium
PULMONARY CIRCULATION
-Flow of blood between the heart and lungs
-Blood flows out of the heart from the right
ventricle and through the pulmonary arteries to
the lungs.
- Waste material (carbon dioxide) from the
body is exchanged for oxygen from the inhaled
air
Heart Blood Supply
Coronary circulation- The delivery of oxygen,
nutrient-rich arterial blood and return of
oxygen poor blood
Right and Left Coronary arteries supply
blood to the heart muscle
Cardiac veins return the blood to the right
atrium thru the cardiac sinus
Terminology
Myocardial infarction- Occlusion of a
coronary artery resulting in an infarct
AKA Heart Attack
Angina Pectoris- Chest pain
Coronary Bypass Surgery- CABG
Cardiac cycle- Complete heartbeat
Terminology
Stroke Volume- The amount of blood ejected
from the ventricles during each beat
Cardiac Output- Volume of blood pumped by
by one ventricle in a minute.
Heart Block- Electrical impulses are blocked
from Getting to the ventricles, heart rate slows
down.
Could result in the need of a pacemaker
Terminology
Sinoatrial Node- S-A node, located right atrium Known as the Pacemaker S-A node impulse travels
to A-V node
Atrioventricular node- A-V node, located right atrium
- Transmits impulse to the Bundle of His
Bundle of His- Carry impulse to Purkinje Fibers
Purkinje Fibers- Causes ventricles to contract
- Simultaneously forces blood into
Aorta, and pulmonary arteries
HEARTBEAT
•To pump blood effectively throughout the
body, the contraction and relaxation
(beating) of the heart must occur in exactly
the correct sequence
•Rate and regularity is determined by the
electrical impulses from nerves
Electrocardiogram
Electrocardiogram- ECG record of the
hearts electrical activity
Depolarization- electrical activity that triggers
contraction of heart muscle
Repolarization- begins before relaxation phase
of cardiac muscle activity
P-Wave - occurs with depolarization of atria
T-Wave – results from electrical activity
generated by repolarization of the ventricles
QRS-complex- occurs with depolarization of
the ventricles
Questions????????????????
Which vessels supply blood directly to the
heart muscle?
What is heart block?
What is the difference between Cardiac
output, and Stroke volume?
BLOOD VESSELS
Arteries: pumps arterial blood (oxygenated)
Arterioles: smallest arteries that control the
flow into microscopic exchange vessels….
…..Capillaries
Principal
Arteries
of the
Body
Capillary beds: where the exchange of
nutrients and respiratory gases occur
between the blood and tissue fluid around
the cells
Blood exits or is drained from the capillary
beds and enters the small venules which
join with other venules and increase in size
becoming veins.
Aorta: largest artery in the body
Vena Cava: returns blood to the heart
after circulation via the inferior and superior
vena cava
STRUCTURE
Arteries, veins, and capillaries differ in
structure
Made up of three layers
Tunica adventitia
Tunica media
Tunica intima
VESSEL LAYERS
Tunica Adventitia
Outermost layer
Made up of connective tissue
VESSEL LAYERS
Tunica Media
Strong middle layer layer
Smooth muscle tissue
Elastic tissue
VESSEL LAYERS
Tunica Intima
Inner layer of endothelial cells
Lines arteries and veins
VESSEL LAYERS
MUSCLE LAYER IMPORTANCE
The thicker layer is meant to withstand
great pressure generated by ventricular
systole
In arteries, the tunica media plays a critical
role in maintaining blood pressure and in
controlling blood distribution
FUNCTIONS OF VESSELS
Arteries and arterioles distribute blood from
the heart to capillaries in all parts of the body
By constriction or dilating, arterioles help to
maintain normal arterial blood pressure
Veins and venules collect blood from
capillaries and return it to the heart
Serve as blood reservoirs because they can
hold large or small amounts of blood
CAPILLARIES
Function as exchange vessels
Example: glucose and oxygen move out of
the blood in capillaries into interstitial fluid
and on into cells.
Carbon dioxide and other substances
move in the opposite direction into the
capillaries from the cells
CIRCULATION
Systemic Pulmonary
Systemic Circulation
Blood flow from the left ventricle of the heart
through blood vessels to all parts of the body
and back to the right atrium
Blood flows out of each organ by way of its
venules and the its veins to drain eventually into
the inferior or superior vena cava
HEPATIC PORTAL
CIRCULATION
The route of blood flows through the liver
Veins from the spleen, stomach, pancreas,
gallbladder, and intestines do not pour
their blood directly into the inferior vena
cava as do the veins
Blood is sent to the liver by means of the hepatic
portal vein.
HEPATIC PORTAL
CIRCULATION Cont
The blood passes through the liver and
reenters the regular venous return to the
heart.
Blood leaves the liver by way of the
hepatic veins
Hepatic veins drain into the inferior
vena cava
PORTAL CIRCULATION Cont
Blood flow in the hepatic portal circulation
does not follow the typical route.
Venous blood, which would ordinarily
return directly to the heart, is sent instead
through a second capillary bed in the liver
Hepatic portal vein is located between
two capillary beds—one set in the
digestive organs and the other in the liver.
HEPATIC
PORTAL
CIRCULATION
FETAL CIRCULATION
Circulation in the body before birth differs
from circulation after birth because the
fetus must secure oxygen and food from
maternal blood instead of its own lungs
and digestive organs
Placenta: exchange of nutrients and
oxygen take place
UMBILICAL CORD
Three vessels accomplish the oxygen,
nutrient exchange and return blood to
the fetal body
Two umbilical arteries
One umbilical vein
FETAL
CIRCULATION
DUCTUS VENOSIS
Continuation of the umbilical vein
Shunts most blood from the placenta
past the immature liver of the baby
Empties directly into the inferior vena
cava
DUCTUS VENOSIS
FORAMEN OVALE
&
DUCTUS ARTERIOSUS
Shunts blood directly from the right
atrium directly into the left atrium
Ductus arteriosus connects the aorta
and the pulmonary artery
FORAMEN OVALE
&
DUCTUS ARTERIOSUS
FETAL SHUNTING
At birth, specialized fetal blood vessels
and shunts must become nonfunctional
When the baby is born the circulatory
system is subjected to increased pressure
Increased pressure results in closure of the
foramen ovale and rapid collapse of the
umbilical blood vessels, the ductus venosus
and the ductus arteriosus
BLOOD PRESSURE
Best way to understand is to answer a few
questions.
What is Blood Pressure?
It is the pressure or push of blood
Where does Blood Pressure exist?
In all blood vessels
Highest in arteries
Lower in veins
PRESSURE GRADIENT
List blood vessels in order according to the
amount of blood pressure in them and draw
a graph it would look like a hill.
• Aortic blood pressure would be at the top
• Vena cava pressure would be at the bottom
• More precisely, the blood pressure gradient
is the difference between two blood pressures
SYSTEMIC PRESSURE
GRADIENT
The difference between the average blood
in the aorta and the blood pressure at the
termination of the venae cavae (where they
join the right atrium of the heart)
The average blood pressure in the aorta is
100 mm of mercury (mm Hg)
The pressure at the termination of the venae
cavae is “0”
PRESSURE
GRADIENT
BP IS IMPORTANT
When blood pressure gradient is not present
• Blood does not circulate
If blood does not circulate
Life itself will soon cease
HIGH BLOOD PRESSURE
Is not a good thing for several reasons
May cause rupture of one or more
blood vessels
-- If this happens in the brain, a
stroke will occur
LOW BLOOD PRESSURE
Can be dangerous
If arterial blood pressure falls low
enough:
-- Circulation and life cease
-- Massive hemorrhage, which will
dramatically reduce blood pressure
kills in this way
FACTORS THAT INFLUENCE BP
Blood Volume: the larger the volume
of blood in the arteries the higher the BP.
The lower the volume, the lower the BP
The volume of blood in the arteries is
determined by how much blood the
heart pumps into the arteries and how
much the arterioles drain out of them
FACTORS THAT INFLUENCE BP
The diameter of the arterioles plays an
important role in determining how much
blood drains out of the arteries into the
arterioles
STRENGTH OF HEART
CONTRACTIONS
The strength and rate of the heartbeat will
affect cardiac output and therefore the BP
Each time the Left Ventricle contracts, it
squeezes a certain volume of blood (stroke
volume) into the aorta and other arteries
The stronger each contraction is, the more
blood it pumps into the aorta and arteries.
the weaker, the less blood
SUMMARY OF HEART
CONTRACTIONS
The strength of the heartbeat affects the
blood pressure in this way:
-- A stronger heartbeat increases blood
pressure, and a weaker beat decreases
blood pressure
HEART RATE
The heartbeat may also affect arterial BP
Does a faster heart beat result in more
blood being pumped into the aorta?
NO. This is true only if the stroke volume
does not decrease sharply when the heart
rate increases
HEART RATE
More often, when the heart beats faster,
each contraction of the left ventricle takes
place so rapidly that it has little time full
and squeezes out much less blood than
usual.
This decreases the arterial blood volume
and therefore blood pressure decreases
even though heart rate has increased
BLOOD VISCOSITY
To be more specific, this is how thick is the
blood
If blood becomes less viscous than normal
blood, the blood pressure will decrease
When this decrease occurs, whole blood or
plasma is preferred before IV saline
Saline solution is not as viscous, therefore
it will not increase the viscosity of blood
POLYCYTHEMIA
This occurs when the number of red blood
cells increase beyond the normal and the
viscosity of blood it increased
This condition causes an increase in BP
This can occur when oxygen levels in the
air decrease and the body attempts to
increase its ability to attract oxygen to the
blood
MAIN
SUPERFICIAL
VEINS
FLUCTUATIONS IN BLOOD
PRESSURE
No one’s blood pressure stays the same
all the time
With exercise higher BP is a good thing.
Provides the body with additional oxygen \
and nutrients during this period
Normal BP is about 120/80
“Normal” varies among individuals and with
age
VENOUS BLOOD PRESSURE
Venous pressure in the right atrium is called
Central Venous Pressure
This pressure is important because it influences
pressure that exists in large peripheral veins
If heartbeat is strong then CVP is low as blood
enters and leaves the heart chambers efficiently
With exercise higher BP is a good thing.
Provides the body with additional oxygen \
and nutrients during this period
PULSE
• The pulse is the alternate expansion and
recoil of the blood vessel wall
PULSE
• Where are some land marks to take
and record the Pulse?
Temporal
Carotid
Brachial
Femoral
Dorsalis Pedis
• Review objectives
• QUESTIONS
• The End