HOC 1 - 16 Cardiovascular System

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Health Occupations
Cardiovascular System
Cardiovascular system

Consists of
– Heart
– Blood vessels
– blood

Transportation system of the body
– Transports oxygen & nutrients to cells
– Transports carbon dioxide & metabolic
waste away from cells
Heart
Hollow, muscular organ
 Pump of body – size of closed fist
 Found in mediastinal cavity

– Between lungs
– Behind sternum
– Above diaphragm
3 layers of heart tissue

Endocardium
– Smooth layer of cells
– Lines inside of heart, continuous with inside of
blood vessels
– Allows for smooth flow of blood

Myocardium
– Thickest layer, muscular, middle layer

Pericardium
– Double layered membrane or sac
– Covers outside of heart
– Pericardial fluid fills the space between 2 layers &
prevents friction & damage to membranes as
heart contracts
Heart septum
Muscular wall
 Separates heart into right & left sides
 Prevents blood from moving right to left
& vice versa
 Interatrial septum

– Upper part

Interventricular septum
– Lower part
Heart chambers

Divided into 4 parts (chambers)
 2 upper – atria
 2 lower- ventricles
 Right atrium
– Receives blood as it returns from the body

Right ventricle
– Receives blood from right atrium
– Pushes blood into pulmonary artery
• Carries blood to lungs for oxygenation
Heart chambers

Left atrium
– Receives blood from lungs (oxygenated)

Left ventricle
– Receives blood from left atrium
– Pushes blood into aorta so it can be
carried to body cells
Valves

One way valves in-between heart chambers
keep blood flowing in right direction
 Tricuspid valve
– Between right atrium & right ventricle
– Closes when right ventricle contracts & pushes
blood to lungs
– Prevents blood from flowing back into right atrium

Pulmonary valve
– Between right ventricle & pulmonary artery
– Closes when right ventricle is finished contracting
& pushing blood into pulmonary artery
– Prevents blood from reentering right ventricle
Valves

Bicuspid or Mitral valve
– Between left atrium & left ventricle
– Closes when left ventricle is contracting & pushing
blood into aorta so it can be carried to the body
– Prevents blood from flowing back into left atrium

Aortic valve
– Between left ventricle & aorta (largest artery in
body)
– Closes when left ventricle is finished contracting &
pushing blood into aorta
– Prevents blood from flowing back into left ventricle
Superior vena cava
Right pulmonary artery
Right pulmonary veins
Pulmonary valve
Right atrium
Tricuspid valve
Right ventricle
Inferior vena cava
Aorta
Left pulmonary artery
Left pulmonary veins
Left atrium
Aortic valve
Bicuspid valve
Left ventricle
Septum
Endocardium
Myocardium
Pericardium
Apex
Cardiac cycle

Right & left sides of the heart work in a cyclic
manner, TOGETHER, even though they are
separated by the septum
 Electrical impulses originating in heart causes
myocardium to contract cyclically
 Cycle consists of
– Diastole
• Period of rest (brief)
– Systole
• Period of ventricular contraction
Cardiac cycle

At start of cycle
– Right & left atria contract
– Blood is pushed into right & left ventricles
through the tricuspid (rt) & bicuspid (lt)
valves
– Atria relax & blood reenters them
• Right side – from body
• Left side – from pulmonary veins (from lung)
Cardiac cycle
While atria are filling, systole begins &
ventricles contract
 Blood exits ventricle through pulmonary
& aortic valves

– Right ventricle
• Pushes blood into pulmonary artery & lungs
– Left ventricle
• Pushes blood into aorta & body
Cardiac cycle

Blood in right side of heart
– Low in oxygen, high in carbon dioxide
– Then it goes to lungs via pulmonary artery
– When it gets to lungs
• Carbon dioxide released into lungs
• Oxygen taken into blood

Blood in left side of heart
– Brought there by pulmonary veins
– Now blood is high in oxygen, low in carbon dioxide
– Ready to go to body
Lungs
Blood to lungs
Blood from lungs
Pulmonary artery
Superior vena cava
Pulmonary veins
Pulmonary valve
Right atrium
Inferior vena cava
Tricuspid valve
Right ventricle
Pericardium
Aorta
Left atrium
Bicuspid valve
Aortic valve
Left ventricle
Endocardium
Septum
Apex
Conductive pathway

Electrical impulses originating in the heart
cause the cyclic contraction of muscles
 Starts in the sinoatrial node (SA node)
– Group of nerve cells located in right atrium
– Called pacemaker
– Sends out an electrical impulse that spreads out
over the muscles in the atria
– Atrial muscles then contract & push blood into
ventricles
– After electrical impulse passes through atria, it
reaches the atrioventricular node (AV node)
Conductive pathway

Atrioventricular node (AV node)
– Groups of nerve cells located between
atria & ventricles
– Sends electrical impulse through nerve
fibers in the septum called the Bundle of
His

Bundle of His
– Nerve fibers in septum
– Divides into a right & left bundle branch
Conductive pathway

Right & left bundle branches
– Pathways that carry the impulse down through the
ventricles
– Bundles continue to subdivide into a network of
nerve fibers throughout the ventricles called
Purkinje fibers

Purkinje fibers
– Final fibers on conduction pathway
– Spread electrical impulse to all of the muscle
tissue in the ventricles
– Ventricles then contract
Conductive pathways
Electrical conduction pattern occurs
every 0.8 seconds
 Movement of the electrical impulse can
be recorded on an ECG & used to
detect abnormal activity or disease

Sinoatrial node
( SA node)
Atrioventricular
Node (AV node)
Bundle of HIS
Purkinje fibers
Left & right bundle branches
Arrhythmias

Interference with normal electrical conduction
pattern of heart
 Causes abnormal heart rhythms
 Can be mild to life threatening
–
–
–
–
–
PAC’s (premature atrial contraction)
Atrial fibrillation (A fib)
PVCs (premature ventricular contraction)
Ventricular fibrillation (V fib)- life threatening
Asystole- life threatening
Arrhythmias

Cardiac monitors & ECG are used to
diagnose
 Treatment depends on type & severity
– Life threatening – treat with defibrillation
• Device that shocks heart with electrical current
• Stops uncoordinated contraction
• Allows SA node to regain control
– External or internal artificial pacemakers
• Small battery powered device with electrodes
• Electrodes threaded through vein into right atrium &
ventricle
• Fixed pacemakers – predetermined rate
• Demand pacemakers – only fire when needed
Normal ECG
Normal sinus rhythm
Premature ventricular contractions
Atrial fibrillation
Ventricular fibrillation
Blood vessels

Blood leaving heart carried via blood vessels
– Closed system for flow of blood
– 3 main types – arteries, veins, capillaries

Arteries
– Carry blood away from heart
– Aorta
• Receives blood from left ventricle
• Immediately begins branching into smaller arteries
– Arterioles
• Smallest branch of arteries
• Joins with capillaries
Blood Vessels

Capillaries
– Connect arterioles with venules
– Thin walled, has only one layer of cells
– Allow oxygen & nutrients to enter cells,
CO2 & waste to leave
Blood Vessels

Veins
– Blood vessels that carry blood back to heart
– Venules
• Smallest branch of veins
• Connect with capillaries
• Venules join together to become veins
– Superior & inferior vena cava
•
•
•
•
2 largest veins
Superior – brings blood from upper part of body
Inferior – brings blood from lower part of body
Both vena cava drain into right atrium
– Much thinner with less muscle than arteries
– Most contain valves that keep blood from flowing
backwards
Blood Composition

Blood is a tissue
 4-6 quarts in average adult
 Circulates continuously through body
 Transports many substances
–
–
–
–
–
–
Oxygen from lungs to cells
Carbon dioxide from cells to lungs
Nutrients from digestive tract to cells
Metabolic wastes from cells to organs of excretion
Heat produced by body parts
Hormones produced by endocrine glands
Blood composition

Plasma
– Fluid or liquid portion of blood
– 90% water
– Many substances dissolved or suspended
•
•
•
•
•
•
•
Blood proteins- fibrinogen & prothrombin for clotting
Nutrients – vitamins, CHO, proteins
Mineral salts or electrolytes
Gases – CO2 & O2
Metabolic & waste products
Hormones
enzymes
Blood Cells

Solid elements of blood
 3 main types
 1. Erythrocytes – red blood cells
– Produced in red marrow at rate of 1,000,000 per
minute
– Live about 120 days, broken down by liver &
spleen
– 4 ½ - 5 ½ million per cubic millimeter of blood (25
trillion)
– Mature form circulating in blood has NO nucleus &
is shaped like a disc with a thinner central area
Erythrocytes

Contain complex protein – HGB
– Composed of protein molecule (globin) &
iron compound (heme)
– Carries both (O2 & CO2)
– When HGB carries O2, it gives blood its
red color
– When there is decreased O2, the blood is
darker red
2. Leukocytes








White blood cells
Not as numerous
Formed in bone marrow & lymph
Live 3 – 9 days
5 – 10,000 per cubic millimeter
Can pass through capillary walls & enter body
tissue
Main function – fight infection
Phagocytosis – process by which some
WBCs engulf, ingest, & destroy pathogens
Leukocytes

5 types
– Neutrophils
• Phagocytize bacteria, secrete lysosomes
– Eosinophils
• Remove toxins, defend from allergic reactions
• Make antihistamines
– Basophils
• Inflammatory response
• Produce histamine (vasodilator) & heparin
(anticoagulant)
– Monocytes
• Phagocytize bacteria & foreign bodies
– Lymphocytes
• Immunity by making antibodies, protect against cancer
formation
3. Thrombocytes
Platelets
 Fragments or pieces of cells
 No nucleus, vary in size & shape
 Formed in bone marrow
 Live 5 – 9 days
 250,000 – 400,000 per cubic millimeter

Thrombocytes – clotting process







Blood vessel torn, thrombocytes collect to
form sticky plug
Secrete serotonin, causes blood vessel
spasm & decreased blood flow
Release thromboplastin, acts with calcium to
form thrombin
Thrombin acts with fibrinogen to make fibrin –
gel like net of fine fibers that trap RBCs, plts,
& plasma to form clot
Effective with small vessel bleeding
If large vessel is torn, rapid blood flow
interferes with fibrin formation
Dr. may insert sutures to close opening &
control bleeding
Blood typing








O+ 38%
O- 7%
A+ 34%
A- 6%
B+ 9%
B- 2%
AB+ 3%
AB- 1%
Abnormal conditions
Anemia – inadequate number of erythrocytes,
HGB, or both
 5 types

– 1. Acute blood loss anemia
• Caused by hemorrhage or rapid blood loss
• TX with transfusion
– 2. Iron deficiency anemia
• Inadequate amount of iron to form HGB in RBCs
• TX with increased iron intake from green leafy
vegetables, red or organ meats, meds
Types of anemias

3. Aplastic anemia
–
–
–
–

Results from injury or destruction of bone marrow
Causes poor or no formation of RBCs
Caused by chemo, radiation, chemicals, viruses
TX – eliminate cause, blood transfusions, bone
marrow transplants
4. Pernicious anemia
– Lack of intrinsic factor, results in poor absorption
of Vitamin B12
– Results in formation of large inadequate RBCs
– Tx – replace intrinsic factor, give Vit B12 shots
Types of anemias

5. Sickle cell anemia
– Chronic & inherited
– Results in production of abnormally
crescent shaped RBCs that carry less
oxygen, break easily, & block blood vessels
– Racially exclusive – black
– Tx – transfusions & supportive therapy,
need genetic counseling to prevent
Aneurysm






Ballooning out or saclike formation on artery
wall
Causes – disease, congenital, injuries leading
to weakening of arterial wall
Sx – some cause pain/pressure & others
have no sx
Common sites – cerebrum, aorta, abd
If rupture – hemorrhage, can cause death
TX – surgical removal of damaged area &
replacement with plastic graft or other vessel
Arteriosclerosis
Hardening or thickening of arterial walls
 Causes loss of elasticity & contractility
 Occurs as result of aging
 Causes HTN & can lead to aneurysm or
cerebral hemorrhage

Atherosclerosis





Fatty plaques, frequently cholesterol on walls
of arteries
Causes narrowing of opening, decreasing or
eliminating blood flow
If plaques break loose, become emboli
TX – low cholesterol diet, meds to lower
cholesterol, exercise
Surgery – balloon angioplasty, coronary
atherectomy, coronary stent, bypass surgery
Congestive Heart Failure (CHF)
Heart muscle doesn’t beat adequately to
supply blood needs of the body
 Involves right or left sides of heart
 Symptoms

–
–
–
–
–
–
Edema
Dyspnea
Pallor & cyanosis
Neck vein distension
Weak & rapid pulse
Productive cough with pink frothy sputum
Congestive Heart Failure

Treatment
– Cardiac drugs
– Diuretics
– TED hose
– Oxygen
– Bedrest
– Low sodium diet
Embolus

Foreign substance circulating in blood stream
–
–
–
–

Air
Fat
Blood clot
Bacterial clumps
Blockage of vessel occurs when embolus
enters an artery or capillary too small for
passage
Hemophilia





Inherited disease occurring almost
exclusively in males, but carried by females
Blood is unable to clot due to lack of plasma
protein
Minor cut can lead to prolonged bleeding
Bump can lead to internal bleeding
Treatment
– Transfusions
– Administration of missing protein factor
HTN - hypertension

Systolic >140 mm Hg
 Diastolic > 100 mm Hg
 Risk factors
–
–
–
–
–
–
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Family history
Obesity
Race
Stress
Smoking
Age
Diet high in saturated fat
HTN

Treatment
–
–
–
–
–
–

No cure
Antihypertensives
Diuretics
Decreased stress
No tobacco
Low sodium & low fat diet
If untreated, causes permanent damage
–
–
–
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Heart
Blood vessels
Kidneys
eyes
Leukemia

Malignant disease of bone marrow or lymph
tissue resulting in large numbers of immature
WBCs
 Can be acute or chronic
 Symptoms
–
–
–
–
–
–
–
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Fever
Pallor
Swelling of lymph tissues
Fatigue
Anemia
Bleeding gums
Excessive bruising
Joint pain
Leukemia

Treatment
– Varies with type
– Chemotherapy
– Radiation
– Bone marrow transplant
Myocardial Infarction (MI)
Blockage in coronary arteries cuts off
supply of blood to heart
 Affected heart tissue dies (infarcts)
 Death can occur immediately if a large
area infarcts
 Also called heart attack
 Angina pectoris can be a precursor

MI

Symptoms
– Severe crushing pain radiating to arm,
neck or jaw
– Pressure in chest
– Diaphoresis
– Cool, clammy skin
– Dyspnea
– BP & pulse changes
MI

Treatment
– CPR if cardiac arrest
– Thrombolytic clot busters (Streptokinase or TPA)
to restore blood flow within the first several hours
– can’t use if bleeding present
– Complete BR
– Pain meds
– Anticoagulants
– Oxygen
– Treatment of arrhythmias
MI

Long term care
– BP control
– Diet low in cholesterol & saturated fats
– No tobacco
– No stress
– Regular exercise
– Weight control
Phlebitis
Inflammation of vein
 Frequently in leg
 Called thrombophlebitis if clot forms
 Symptoms

– Pain
– Edema
– Redness
– Discoloration at site
Phlebitis

Treatment
– Anticoagulants
– Pain meds
– Elevate area
– TED hose
– Surgery
Varicose veins

Dilated & swollen veins that have lost
elasticity & cause a stasis or decreased blood
flow
 Occurs frequently in legs
 Results from pregnancy, prolonged sitting or
standing, heredity
 Treatment
–
–
–
–
–
Exercise
Avoid prolonged sitting/standing
TED hose
No tight-fitting clothing
Surgery to remove vein in severe cases
Erythroblastosis fetalis

Condition in unborn baby where mom forms
antibodies against the antigens in the baby’s
blood
 RH+ child (after 1st pregnancy) born to RHmother
 May cause brain damage in baby
 Treatment
– Monitor bilirubin levels during pregnancy
– Intrauterine transfusions if needed
– May need exchange transfusions at birth
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