The Heart Pumps Blood Through
Blood Vessels to All Tissues
LEARNING OBJECTIVES
1.
Identify
the structural features of the heart.
2.
Outline
the flow of blood through the heart.
3.
Explain
how the electrical conduction system of
the heart works.
ike city pumping stations, which circulate
water to your house and off to the waste-wa-
ter treatment plant, your body’s cardiovascu-
lar system circulates blood, gases, nutrients,
and wastes throughout your body (Figure 11.1). This
system consists of a single pump (your heart), and be-
tween 60,000 to 100,000 km (36,000 to 60,000 miles) of
blood vessels. Your heart actually consists of two pumps
4.
Identify
parts of an electrocardiogram and pos-
sible abnormalities.
5.
Describe
each phase of the cardiac cycle.
6.
Define
cardiac output and identify the factors
that regulate it.
in one. The right side collects oxygen-poor blood from
the body and pumps it to the lungs. At the same time,
the left side collects oxygen-rich blood from the lungs
and propels it through the rest of the body. This essential
muscular organ contracts about 100,000 times every day,
which adds up to 35 million beats in a year. In total, the
heart pumps over 8640 L (2282 gal) of blood each day and
3.2 million L (833,000 gallons) in a year.
O verview o f th e cardiovascular sy stem • Figure 11.1
The cardiovascular system consists of two divisions: the pulmonary circulation (between
the heart and the lungs) and the systemic circulation (between the heart and the body).
CO,
O
,
Aorta
CO,
CO,
O2 O2
Left atrium
CO,
O
,
'2
Gas exchange, nutrient
delivery, and waste
removal occur in the head
upper body, and arms
Right lung
Heart is actually two pumps in
one casing:
• Right side—low pressure
• Left side—high pressure
Superior vena cava
Right atrium
Right ventricle
Inferior vena cava
1
Left ventricle
Aorta
Left lung
Gas exchange, nutrient
delivery, and waste
removal occur in the
abdomen, lower body,
and legs.
Pulmonary circulation
exchanges oxygen from
air for carbon dioxide
from tissues.
Systemic circulation exchanges
carbon dioxide from tissues of the body
for oxygen from the lungs. Systemic
circulation also delivers nutrients to
310
and removes waste from tissues.
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