-
The Cardiovascular
System
Gerard Mark C. Santos
Department of Natural Sciences
College of Arts and Sciences
San Beda College
-
Functions of the Heart
1. Generating blood pressure
Required for blood flow through the blood vessels
2. Routing blood
Two pumps, moving blood through the pulmonary and systemic
circulations
3. Regulating blood supply
Adjusts blood flow by changing the rate and force of heart
contractions as needed
-
Systemic and Pulmonary Circulation
Pulmonary circulation
The flow of blood from the heart through the
lungs back to the heart
Picks up oxygen and releases carbon dioxide
in the lungs
System circulation
The flow of blood from the heart through the
body back to the heart
Delivers oxygen and picks up carbon dioxide
in the bodys tissues
Fig. 17.1
-
Heart in the Pericardium
Fig. 17.3
-
Heart Wall
Fig. 17.4
-
Internal Anatomy of the Heart
Fig. 17.6
-
Function of the Heart Valves
Fig. 17.8
-
Fig. 17.9
Blood
Flow
Through
the Heart
-
Fig.
17.13
-
Cardiac Cycle
Repetitive contraction and relaxation of the heart chambers
Overview of Systole and Diastole Atrial systole is contraction
of the atria
Systole is contraction of the ventricles
Atrial diastole is relaxation of the atria
Diastole is relaxation of the ventricles
-
Fig.
17.15
Cardiac
Cycle
-
Cardiac Cycle
Heart sounds (lub-dup) are associated with closing of heart
valves
First sound occurs as AV valves close and signifies beginning of
systole
Second sound occurs when SL valves close at the beginning of
ventricular diastole
-
Fig.
17.17
-
Baroreceptor and Chemoreceptor Reflexes
Fig. 17.18
-
Effects of Aging on the Heart
Aging results in gradual changes in the function of the heart,
which are minor under resting conditions but are more significant
during exercise
Some age-related changes to the heart are the following
Decreased cardiac output and heart rate Increased cardiac
arrhythmias Hypertrophy of the left ventricle Development of
stenoses or incompetent valves Development of coronary artery
disease and heart
failure
Exercise improves the functional capacity of the heart at all
ages.
-
Functions of the Peripheral Circulation
The heart provides the major force that causes blood to
circulate
The peripheral circulation
1. Carries blood
2. Exchanges nutrients, waste products, and
gases with tissues
3. Helps regulate blood pressure
4. Directs blood flow to tissues
-
General Features of Blood Vessels
Arteries carry blood away from the heart toward capillaries,
where exchange between
the blood and interstitial fluid occurs
Blood flows from the heart through elastic arteries, muscular
arteries, and arterioles to the capillaries
Veins carry blood from the capillaries toward the heart
Blood returns to the heart from the capillaries through venules,
small veins, and large veins
-
Fig. 18.2
-
Fig. 18.1
-
Fig. 18.4
-
Aging of the Arteries
Arteriosclerosis results from a loss of elasticity in the aorta,
large arteries, and
coronary arteries
Atherosclerosis is the deposition of materials in arterial walls
to form plaques
-
Systemic Circulation: Arteries
Arteries carry blood
from the left ventricle
of the heart to all
parts of the body
Fig. 18.6
-
Fig.
18.17
Major Veins
-
Physiology of Circulation
Blood Pressure
A measure of the force exerted by blood against the blood vessel
wall. Blood moves
through vessels because of blood pressure
Can be measured by listening for Korotkoff sounds produced by
turbulent flow in
arteries as pressure is released from a
blood pressure cuff
-
Fig.
18.29
-
Examples of Cardiovascular Regulation
Exercise
Local control mechanisms increase blood flow through exercising
muscles, which lowers peripheral resistance
Cardiac output increases because of increased venous return,
stroke volume, and heart rate
Vasoconstriction in the skin, the kidneys, the gastrointestinal
tract, and skeletal muscle (non-
exercising and exercising) increases peripheral
resistance, which helps prevent a drop in blood
pressure
Blood pressure increased despite an overall decrease in
peripheral resistance because of increased cardiac
output
-
Page
559
