10.4 The Vascular Pathways

Question 1

What are the 2 circuits of the circulatory system?

Answer 1

pulmonary circuit and systemic circuit

Question 2

What does the pulmonary circuit do?

Answer 2

circulates blood through the lungs

Question 3

What does the systemic circuit do?

Answer 3

serves the needs of body tissues

Question 4

Describe the pulmonary circuit path.

Answer 4

• blood from all regions of the body first collects in the right atrium
• then passes into the right ventricle, which pumps it into the pulmonary trunk
• pulmonary trunk divides into the right and left pulmonary arteries, which branch as they approach the lungs
• arterioles take blood to the pulmonary capillaries, where gas exchange occurs
• blood then passes through the pulmonary venules, which lead to the 4 pulmonary veins (2 from each lung) that enter the left atrium

Question 5

Why is it not correct to say that all arteries carry blood high in oxygen and all veins carry blood low in oxygen?

Answer 5

because blood in the pulmonary arteries is oxygen poor but blood in the pulmonary veins is oxygen rich in the pulmonary circuit (reverse)

Question 6

Where is blood in the pulmonary arteries is oxygen poor but blood in the pulmonary veins is oxygen rich?

Answer 6

• pulmonary circuit

- umbilical arteries and vein of a developing fetus

Question 7

What does the systemic circuit include?

Answer 7

major arteries and veins

Question 8

What is the largest artery in the systemic circuit?

Answer 8

aorta

Question 9

What are the largest veins in the systemic circuit?

Answer 9

venae cavae

Question 10

What does the superior vena cava collect?

Answer 10

blood from the head, chest, arms

Question 11

What does the inferior vena cava collect?

Answer 11

blood from the lower body regions

Question 12

Where do the venae cavae enter in the systemic system?

Answer 12

right atrium

Question 13

What do the aorta and venae cavae do in the systemic circuit?

Answer 13

they serve as the major pathways for blood

Question 14

Where does the path of systemic blood to any organ in the body begin?

Answer 14

left ventricle

Question 15

Describe the path of blood to and from the legs.

Answer 15

left ventricle
aorta
common iliac artery
femoral artery
leg capillaries
femoral vein
common iliac vein
inferior vena cava
right atrium

Question 16

What do you need to mention when tracing the path of blood?

Answer 16

• aorta
• proper branch of the aorta
• region
• vein returning blood to the vena cava

in most instances, artery and vein that serve the same region are given the same name

Question 17

What do coronary arteries do?

Answer 17

serve the heart muscle itself (the heart is not nourished by the blood in its own chambers)

Question 18

Where are the coronary arteries?

Answer 18

the first branches off the aorta

they originate just above the aortic semilunar valve, and they lie on the exterior surface of the heart, where they divide into diverse arterioles

Question 19

Why may coronary arteries become clogged?

Answer 19

they have a very small diameter

Question 20

What do coronary capillary beds form?

Answer 20

they join to form venules that converge to form the cardiac veins, which empty into the right atrium

Question 21

What is the portal system?

Answer 21

a pathway of blood flow that begins and ends in capillaries

Question 22

What is the hepatic portal system?

Answer 22

portal system associated with the liver

capillaries that occur in the villi of the small intestine pass into venules that join to form the hepatic portal vein

Question 23

What does the hepatic portal vein do?

Answer 23

carries the blood to a set of capillaries in the liver

Question 24

Where does the hepatic portal vein go through?

Answer 24

leaves the liver and enters the inferior vena cava

Question 25

What is the liver?

Answer 25

an organ that monitors the makeup of the blood

Question 26

What happens when the left ventricle contracts?

Answer 26

blood is forced into the aorta and then into other systemic arteries under pressure

Question 27

What is systolic pressure?

Answer 27

results from blood being forced into the arteries during ventricular systole

Question 28

What is diastolic pressure?

Answer 28

the pressure in the arteries during ventricular diastole

Question 29

Describe blood pressure as blood flows from the aorta into the arteries and arterioles?

Answer 29

• blood pressure falls

- difference between systolic and diastolic pressure gradually diminishes

Question 30

Why is blood flow slow and fairly even in the capillaries?

Answer 30

may be related to the very high total cross-sectional area of the capillaries

Question 31

How long would all the blood vessels of the body be?

Answer 31

total distance would reach around Earth at the equator 2 times, most due to the large number of capillaries

Question 32

What is blood pressure?

Answer 32

measurement of the force of blood pushing against the inside wall of blood vessels

Question 33

What is a sphymomanometer?

Answer 33

measures blood pressure with a pressure cuff that determines the amount of pressure required to stop the flow of blood through an artery

Question 34

Where is blood pressure measured?

Answer 34

normally on the brachial artery, an artery in the upper arm

Question 35

Describe blood pressure in the veins.

Answer 35

low, by itself is an inefficient means of moving blood back to the heart especially from the limbs

Question 36

What happens when skeletal muscles near veins contract?

Answer 36

they put pressure on the veins and the blood they contain

Question 37

What do valves do?

Answer 37

prevent back flow of blood in the veins and therefore muscle contraction is sufficient to move blood toward the heart

Question 38

What happens in the veins during long periods of sitting or other inactivity?

Answer 38

clots may form in the deep veins of the legs