Download Circulatory System Introduction Cardiovascular System Anatomy

Introduction
Chapter 19
Circulatory System
• The body is 60–80% fluid
• The cardiovascular system circulates
blood and the lymphatic-immune vascular
system circulates lymph
• Collectively referred to as the circulatory
system, they are responsible for fluid
movement and maintenance
__________________________________________________________________________________________
Susan G. Salvo
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Cardiovascular System
Anatomy
• Consists of the blood, blood vessels, and
heart
• Blood is the primary system transport
medium
• Thousands of miles of blood vessels
create a vast network of circulation
• Pumping action of the heart transports
blood
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• Blood
• Blood vessels
• Heart
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Physiology
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Blood
• Transportation and distribution of
respiratory gases, nutrients, antibodies,
waste materials, hormones, and heat
• Protection of the body through diseasefighting white blood cells and the removal
of impurities and pathogens
• Prevention of hemorrhage and loss of
body fluids
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• Blood is a fluid containing erythrocytes,
leukocytes, and suspended platelets
• Classified as liquid connective tissue that
carries oxygen and nutrients to all cells of
the body
• Comprises ~8% of total body weight
• Made up of ~55% liquid plasma and ~45%
solid formed elements
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Characteristics of Blood
Blood Components
• Plasma is a liquid
component that
helps transport
blood cells; is
90% water and
10% solutes:
• Blood is a viscous fluid with many
characteristics:
– Viscous and more adhesive than water
– Slightly alkaline pH
– Color varies from bright scarlet to dull
maroon, depending on oxygen content
– Warmer (100° F) than the rest of the body
– Fibrinogen
– Hormones
– Enzymes
– Proteins
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Blood Cells
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Blood Cells
• Blood cells are formed primarily in the red
marrow of long, flat, and irregular bones
• All blood cell types are produced from
pluripotent stem cells—a single,
undifferentiated cell
• Three types of blood cells: erythrocytes,
leukocytes, and thrombocytes
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Erythrocytes
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Leukocytes
• Red blood cells or RBCs
• Most numerous
• Color from iron-containing hemoglobin
– Biconcave shape allows for greater surface
area and easier movement through capillaries
– Hemoglobin, an iron-based protein, binds and
transports oxygen to cells and tissues
• Transport oxygen to cells and carbon
dioxide from cells to lungs for elimination
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• White blood cells, or WBC’s
• Function as part of immune system by
protecting the body from pathogens
• Are body’s mobile army
• Some WBCs produce histamine as part of
an allergic reaction
• Other WBCs produce antibodies in
response to specific foreign substances
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Thrombocytes
Blood Types
• Also known as platelets
• Primary function is blood clotting
• Use three mechanisms:
• Determined by antigens, genetically
determined protein on RBCs’ surfaces
• Blood type (A, B, AB, and O) compatibility:
– Vascular spasm—tear in vessel wall causes
spasm and reduced blood flow
– Platelet plug—platelets get larger and sticky,
forming a plug
– Coagulation—fibrinogen turns to fibrin and
tightens the platelet plug; Vitamin K is needed
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The Heart
• Rh factor determined by Rh protein
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Heart Coverings and Heart Wall
• About the size of a clenched fist
• Four hollow heart chambers pump blood
to the lungs to be oxygenated and then
pump the oxygenated blood throughout
the body
• Beats approximately 70 beats per minute
or 100,000 beats each day
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– Type A cannot receive blood with B antigen;
can receive A and O
– Type B cannot receive blood with A antigen;
can receive B and O
– Type AB is universal recipient
– Type O is universal donor
• Double-layered pericardium surrounds
heart
• Heart wall possesses three layers
– Epicardium—outer, protective layer that
nourishes the heart
– Myocardium—thick, middle layer of the
cardiac muscle which contracts
– Endocardium—thin, inner lining of the heart
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Heart Chambers
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Heart Chamber
• Atria: thin-walled superior chambers
• Four hollow
chambers:
– R atrium: receives blood from body (except
lungs) and moves it to right ventricle
– L atrium: receives blood from pulmonary veins
and moves it to left ventricle
– Right atrium
– Right ventricle
– Left atrium
– Left ventricle
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Heart Chamber
Heart Valves
• Ventricles: Thick-walled inferior chambers
• Flaps of endothelium between heart
chambers and vessels keep blood flowing
in one direction
• Atrioventricular (AV) valves are the
tricuspid on the right and mitral (or
bicuspid) on the left
• The pulmonary and aortic SL valves
separate ventricles from arteries
– R ventricle: receives blood from the right
atrium and moves it through pulmonary trunk
to lungs
– L ventricle: receives blood from the left atrium
and moves it to the aorta and then throughout
the body
• Stroke volume: amount of blood ejected
from the left ventricle during each
contraction
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Chambers and Valves During
Cardiac Cycle
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Heart Conduction
• The majority of heart rate changes are
controlled by the medulla oblongata
• Other factors influencing heart rate:
– Sympathetic division of automatic nervous
system
– Parasympathetic division of automatic
nervous system
– Chemoreceptor input
– Temperature
– Age and general health
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Heart’s Conduction System
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Blood Vessel Types
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• Arteries—move
oxygenated blood away
from heart
• Capillaries—functional
unit of cardiovascular
system; where gas
exchange occurs; blood
moves slowly
• Veins—move
deoxygenated blood toward
heart, one-way valves
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Blood Vessels
Pulse
• When left ventricle contracts, a surge of
blood briefly expands the arteries
• Each pulse can be felt on arteries located
near surface
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Pulse Points
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Skeletal Muscle Pump
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Blood Pressure
Blood Pressure
• Pressure exerted by blood on arterial walls
during left ventricular contraction
• Measured using a sphygmomanometer
(blood pressure cuff)
• Normal range centers on 120/80 mmHg
• High blood pressure makes heart work
harder and can damage heart and blood
vessels
• Systole: Pressure exerted on arterial walls
during ventricular contraction
• Diastole: Pressure exerted on arterial
walls during the pause between ventricular
contractions
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Blood Pressure
Blood Circulation
• Pressure influenced by many factors:
• Blood flows in two circuits
• Pulmonary circuit:
– Resistance
– Cardiac output
– Blood volume
– Homeostatic regulation
– Diseases
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– from heart to lungs and back
– replenishes blood with oxygen,
eliminates gaseous waste (CO2)
• Systemic circuit:
– from heart to rest of body and
back
– brings nutrients and oxygen to all
systems
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Hepatic Portal System
Major Arteries (a) and Veins (v)
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• A portion of the blood returning to heart is
detoured through the hepatic portal
system, which
– Collects blood from digestive organs and
delivers it to the liver for processing
– Returns nutrients from liver to the blood to be
delivered to the rest of body’s systems
• Does not contain arteries; begins and
ends with veins
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Major Arteries (a) and Veins (v)
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•
•
Aorta (a)
Axillary (a,v)
Brachial (a,v)
Brachiocephalic (a,v)
Carotid (a)
Common Peroneal (a)
Coronary (a)
Dorsalis pedis (a)
Femoral (a,v)
Iliac (a,v)
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Lymphatic System
Jugular (v)
Median cubital (v)
Mesenteric (a)
Popliteal (a,v)
Radial (a,v)
Saphenous (v)
Subclavian (a,v)
Tibial (a,v)
Ulnar (a,v)
Vena Cava (v)
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• Lymphatic-immune system drains excess
fluid from body’s systems and has
disease-fighting functions
• Transports fats and vitamins A, D, E, and
K to blood via lacteals
• Provides immunity by filtering pathogens
and impurities at lymph nodes
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Anatomy
•
•
•
•
•
Physiology
Lymph
Lymph vessels
Lymph glands
Lymphocytes
Lymphatic organs
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• Drains excess interstitial fluid
• Transports dietary lipids and lipid-soluble
vitamins (A, D, E and K) from the digestive
tract to the blood
• Provides immunity against disease
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Lymph Vessels
Lymph Organs
• Lymphatics include
capillaries, vessels,
trunks and ducts
• Lymph travels in only
one direction—
toward subclavian
veins
• No pump—relies on
pressure exerted on
vessel walls
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•
•
•
•
•
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Bone marrow
Thymus gland
Spleen—largest
Lymph nodes—along lymphatic vessels
Mucosal associated lymphoid tissue
(MALT):
– Tonsils—around throat
– Peyer’s patches—in small intestines
– Vermiform appendix—beneath cecum
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Lymph Circulation
Natural and Acquired Immunity
• Lymph starts as interstitial fluid, moves
into lymph capillaries and into lymph
vessels
• Periodically, lymph flows into lymph nodes
for cleansing and filtering
• Converges into one of two ducts
• Natural—nonspecific response to invading
pathogens utilizing:
– Right lymphatic duct—empties into right
subclavian vein
– Thoracic duct—drains most of body and
empties into left subclavian veins
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– Physical and chemical barriers
– Complement proteins
– Phagocytes
– Fever and inflammation
• Acquired—diverse but specific responses
to invaders utilizing B and T cells
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B and T Cell Development
B, T and Natural Killer Cells
• B and T cells must come into contact with
a pathogen to mount an immune response
• Once B and T cells encounter a pathogen,
they are activated for that specific
pathogen
• Natural killer cells are not B or T cells; they
bind to pathogens and cancer cells to kill
them
• Bone marrow
produces lymphocytes
• Two main types of
lymphocytes:
– B cells—continue to
mature in red bone
marrow
– T cells—travel to
thymus complete
maturation
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Pathological Conditions of the
Cardiovascular System
Pathological Conditions of the
Cardiovascular System
• Anemia—reduction in oxygen-carrying
capacity of blood
• Aneurism—weakened section of a blood
vessel wall that bulges outward
• Angina pectoris—constriction of coronary
arteries and myocardial anoxia
• Arteriosclerosis—hardening of arteries
• Atherosclerosis—narrowing of arteries
• Coronary artery disease—narrowing of
arteries; reduced blood flow to heart
• Embolism—blood clot, air bubble, or
debris transported in bloodstream
• Heart murmur—abnormal heart sounds
caused by problems with the heart valves
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Pathological Conditions of the
Cardiovascular System
Pathological Conditions of the
Cardiovascular System
• Hematoma—a localized collection of blood
trapped in tissues of organs, body space
or skin
• Hypertension—elevated blood pressure
• Migraine and cluster headaches—dilation
of extracranial blood vessels
• Peripheral Vascular Disease—numbness,
pain and elevated blood pressure affecting
both blood and lymph vessels
• Phlebitis—inflammation of the veins, often
accompanied by blood clot
• Raynaud’s syndrome—periodic
vasospasm in vessels of the extremities
• Sickle cell disease—abnormally shaped
hemoglobin, which reduces oxygen
supplied to tissues
• Telangiectasia—permanent dilation of
capillaries, venules, or arterioles
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Pathological Conditions of the
Cardiovascular System
Pathological Conditions of the
Lymphatic-Immune System
• Thrombophlebitis—thrombus formation in
an unbroken blood vessel
• Transient Ischemic Attack (TIA)—event of
temporary cerebral dysfunction caused by
ischemia or reduced blood flow
• Varicose veins—dilated veins resulting
from back pressure on incompetent valves
• Acquired immunodeficiency syndrome—
characterized by an array of opportunistic
infections and a low T-cell count
• Allergies—immune system hypersensitivity
and overreaction to otherwise harmless
agents
• Chronic fatigue syndrome—characterized
by disabling fatigue and flu-like symptoms
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Pathological Conditions of the
Lymphatic-Immune System
Summary
• Edema—abnormal accumulation of
interstitial fluid in body tissues
• Lupus Erythematosus—autoimmune,
inflammatory connective tissue disease
• Mononucleosis—acute viral infection that
results from the Epstein-Barr virus
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• Cardiovascular and lymphatic systems
work together as body’s transport system
• Main components of cardiovascular
system are blood, heart and vascular
system.
• Lymphatic-immune system collects, filters,
and recycles fluids into circulation
• Two types of immunity are natural and
acquired
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