Download Chapter 9 The Circulatory System

The Circulatory System
A. Introduction
1. Purpose of the circulation
2. ~9% of population die from cardiovascular diseases
3. Components of the system
a. Cardiovascular system = blood, vessels, heart
b. Lymphatic system = lymph, vessels, lymphoid organs
4. General route of the circulation
The Circulatory System
B. Blood
1. Formed elements
a. Erythrocytes (red blood cells, RBCs)
i.
Not a true cell
ii.
Hemoglobin
b. Leukocytes (white blood cells, WBCs)
(neutrophils, eosinophils, basophils, monocytes, lymphocytes)
c.
Thrombocytes (platelets)
2. Plasma = 91.5% water, 8.5% solutes
The Circulatory System
C. Heart
1. Location
2. Endocardium, myocardium (heart muscle), epicardium
a. Atrial muscle mass
b. Ventricular muscle mass
c.
Cardiac skeleton
The Circulatory System
C. Heart
3. Chambers
a. Right and left atrium
b. Right and left ventricle
c.
Interatrial septum
d. Interventricular septum
4. Valves
a. Atrioventricular (AV) valves
i.
Tricuspid
ii.
Bicuspid (mitral)
b. Semilunar valves
The Circulatory System
C. Heart
5. Great vessels
a. Superior vena cava
b. Inferior vena cava
c.
Pulmonary trunk  right and left
pulmonary arteries
d. Pulmonary veins
e. Aorta
The Circulatory System
C. Heart
6. Coronary arteries
right
coronary
artery
left
coronary
artery
circumflex
artery
marginal
artery
posterior
interventricular artery
anterior interventricular artery
(left anterior descending a.)
The Circulatory System
C. Heart
7. Conduction system
8. Cardiac cycle
Arrows indicate direction of conduction
sinoatrial node
atrioventricular node
a. Systole
b. Diastole
left bundle
branch
9. Cardiac output
a. CO = SV x HR
b. ~5 L/min
10. Cardiac reserve
AV bundle
right bundle branch
Purkinje fibers
The Circulatory System
D. Blood vessels
1. Structure
a. Tunica intima (endothelium)
b. Tunica media
c.
Tunica adventitia
2. Organization
a. Heart  arteries  arterioles 
b. Capillaries 
c.
Venules  veins with valves 
heart
The Circulatory System
E. Lymphatic system
1. Organization
a. Lymph  lymphatic capillaries 
b. Lymphatic vessels  lymph nodes 
c.
Lymph ducts  back to the blood
2. Organs = bone marrow, nodes,
thymus, spleen
3. Functions
a. Return tissue fluid to blood
b. Production of lymphocytes = immunity
c.
Absorption of dietary lipids
The Circulatory System
F. Age-related changes
1. Blood
a. No major changes
b. Total volume begins to decrease >80
c.
Hematocrit and hemoglobin decrease >65
d. Plasma proteins tend to decrease, but fibrinogen (major
clotting factor) tends to increase by 25% >70
e. Red marrow replaced by yellow marrow; new blood cell
formation may decrease
The Circulatory System
F. Age-related changes
2. Heart
a. Slight reduction in size
b. General decrease in size and number of myocardial cells, with
some loss in strength
c.
Increased fat deposition on heart surface
d. Lipofuscin accumulation in myocardial cells
e. Endocardium and valves thicken and may sclerose
The Circulatory System
F. Age-related changes
2. Heart
f.
Increase in elastin and reticular fibers, and fat, within cells
of the conduction system
g. Maximum oxygen consumption value begins to fall at 30;
may be 40% reduction by 65
h. Heart rate decreases
i.
Cardiac output and cardiac reserve decrease
The Circulatory System
F. Age-related changes
3. Blood vessels
a. Loss of arterial elasticity (50% reduction >70)
b. Increased collagen in walls of arterioles
c.
Narrowing of vessel internal diameters by gradual
accumulation of lipid
d. Venous walls thicken and calcify in spots
e. Peripheral resistance gradually increases as a result of
these changes
f.
Increased blood pressure
The Circulatory System
G. Age-related dysfunctions
1. Atherosclerosis and arteriosclerosis
a. Plaque formation due to excess LDLs
i.
Common locations
ii.
Plaques narrow vessel diameters
iii.
Promote clot formation
iv.
Arteriosclerosis formation
b. Effects of smoking and coffee
c.
You can’t escape your heredity
The Circulatory System
G. Age-related dysfunctions
2. Hypertension (pre = 130/80) (stage 1 = 140/90)
a. Incidence increases with age (30% >65)
b. Causes
c.
Effects
i.
Heart attack
ii.
Heart failure
iii.
Kidney failure
iv.
Rupture of blood vessels
The Circulatory System
G. Age-related dysfunctions
3. Coronary artery disease
a. Insufficient blood flow to cardiac muscle
b. Leads to ischemic heart disease
c.
Normally, 65% maximum coronary blood flow at age 65
d. Atherosclerosis is #1 cause
e. Treatment options
The Circulatory System
G. Age-related dysfunctions
4. Angina pectoris
a. Pain related to cardiac ischemia
b. Result of progressively constricted coronary arteries
c.
Usually atherosclerosis-induced
d. Occurs with exertion
e. Always a harbinger of impending heart attack
f.
Treatments
The Circulatory System
G. Age-related dysfunctions
5. Myocardial infarction (heart attack)
a. Result of coronary artery blockage
b. What is an infarction?
c.
Three zones of damage
d. Effects
i.
Decreased cardiac output = decreased blood pressure
ii.
Venous accumulation of blood = pulmonary edema
The Circulatory System
G. Age-related dysfunctions
6. Cardiac dysrhythmias
a. Irregular heartbeats
b. More common with age
c.
Not necessarily pathological
d. Bradycardia vs. tachycardia
e. Flutter vs. fibrillation
f.
Results
g. Treatments
The Circulatory System
G. Age-related dysfunctions
7. Congestive heart failure
a. AKA = cardiac insufficiency – heart unable to pump enough
blood to meet the body’s need
b. If the left heart doesn’t pump out what it gets in, there is a
damming effect in the lungs
c.
If the right heart doesn’t pump out what it gets in, there is a
damming effect in the systemic veins
d. Relationship to kidney function
e. Treatments
The Circulatory System
H. Take home messages
1. No changes in volume, composition, or components of
blood with aging
2. Heart enlarges and weakens as a result of CV disease
3. Blood pressure increases, while stroke volume,
maximum heart rate, cardiac output, and cardiac
reserve decrease
4. Valves thicken and calcify
5. Decreased elasticity of blood vessels
end