The Circulatory System

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The Circulatory System

• Purpose of the circulation
• 9 of population die from cardiovascular
  disease
• Cardiovascular system

blood, blood vessels, heart

• Lymphatic system

lymph, lymphatic vessels, lymphoid organs

• General route of circulation

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The Circulatory System

• Blood

• formed elements

• plasma

3
The Circulatory System

• Heart

• heart muscle myocardium

• atrial mass
• ventricular mass

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The Circulatory System

• Heart

• chambers

• right and left atria
• right and left ventricles
• interatrial septum
• interventricular septum

• valves

• atrioventricular (AV) valves
• semilunar valves

5
The Circulatory System

• Heart

• great vessels

• superior vena cava
• inferior vena cava
• coronary sinus
• pulmonary trunk
• pulmonary veins
• aorta

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The Circulatory System

• Heart

• coronary arteries
• systole vs. diastole
• conduction system

• sinoatrial node
• atrioventricular node
• atrioventricular bundle (of His)
• right and left bundle branches
• Purkinje fibers

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The Circulatory System

• Blood vessels

• structure

• tunica intima (endothelium)
• tunica media
• tunica adventitia

• organization

• heart ---arteries --- arterioles ---
• capillaries ---
• venules --- veins --- heart

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The Circulatory System

• Lymphatic system

• organization

• lymph
• lymphatic vessels
• lymph nodes
• lymph ducts

• functions

• return tissue fluid to blood
• provide immunity
• absorption of dietary lipids

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Age-related changes in the circulatory system

• Blood

• no major changes
• total volume begins to diminish 80
• hematocrit and hemoglobin diminish 65
• plasma proteins tend to decrease, but
  fibrinogen tends to increase by 25 70
• red marrow replaced by yellow marrow, therefore
  new blood cell formation rate may decrease

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Age-related changes in the circulatory system

• Heart

• slight reduction in size
• general decrease in size and number of
  myocardial cells, with some loss of strength
• increased fat deposition on heart surface
• lipofuscin accumulation within cells
• endocardium and valves thicken and may sclerose

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Age-related changes in the circulatory system

• Heart

• increase in elastic and reticular fibers, and
  fat, within cells of conduction system
• blood pressure increases
• maximum oxygen consumption value begins to fall
  at 30 may be 40 reduction at 65
• heart rate decreases
• cardiac output and cardiac reserve decrease

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Age-related changes in the circulatory system

• Blood vessels

• loss of arterial elasticity (50 reduction 70)
• increased collagen in walls of arterioles
• narrowing of vessel internal diameters by
  gradual accumulation of lipid
• venous walls thicken and calcify in spots
• peripheral resistance gradually increases as a
  result of vessel changes

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Age-related dysfunctions in the circulatory system

• Atherosclerosis and arteriosclerosis

• plaque formation due to excess LDLs

• locations
• narrow vessel diameters
• promote clot formation
• arteriosclerosis formation

• effects of smoking and coffee
• heredity

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Age-related dysfunctions in the circulatory system

• Hypertension (170/90)

• incidence increases with age (30 65)
• causes
• effects

• heart attack
• heart failure
• kidney failure
• rupture of blood vessels

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Age-related dysfunctions in the circulatory system

• Coronary artery disease

• insufficient blood flow to cardiac muscle
• leads to ischemic heart disease
• normally, 65 maximum coronary blood flow at 65
• atherosclerosis 1 cause of disease
• treatments

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Age-related dysfunctions in the circulatory system

• Myocardial infarction (heart attack)

• result of coronary artery blockage
• What is an infarction?
• three zones of damage
• effects

• decreased cardiac output decreased blood
  pressure
• venous accumulation of blood pulmonary edema

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Age-related dysfunctions in the circulatory system

• Angina pectoris

• pain related to cardiac ischemia
• result of progressively constricted coronary
  arteries usually atherosclerosis-induced
• occurs with exertion
• always harbinger of impending heart attack
• treatments

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Age-related dysfunctions in the circulatory system

• Cardiac arrhythmias (dysrhythmias)

• irregular heart beats
• more common with age
• not necessarily pathological
• bradycardia vs. tachycardia
• flutter vs. fibrillation
• results
• treatments

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Age-related dysfunctions in the circulatory system

• Congestive heart failure

• AKA - cardiac insufficiency - heart unable to
  pump enough blood to meet the bodys needs
• result of other cardiovascular diseases which
  cause heart compensation
• relationship to kidney function
• symptoms
• treatments

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Take home messages about circulation

• no changes in volume, composition, or
  components of blood with aging
• heart enlarges and weakens as a result of CV
  disease cardiac output decreases
• blood pressure increases while stroke volume,
  maximum heart rate, and cardiac reserve decrease
• valves thicken and calcify
• decreased elasticity of blood vessels