Textbook Question
Which of the following can lead to decreased venous return of blood to the heart?
a. An increase in blood volume
b. An increase in venous pressure
c. Damage to the venous valves
d. Increased muscular activity
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Ch. 19 The Cardiovascular System: Blood Vessels
Marieb, Hoehn7th EditionHuman Anatomy & PhysiologyISBN: 9780805359091
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Table of contents
- Ch. 1 The Human Body: An Orientation24
- Ch. 2 Chemistry Comes Alive25
- Ch. 3 Cells: The Living Units24
- Ch. 4 Tissue: The Living Fabric19
- Ch. 5 The Integumentary System10
- Ch. 6 Bones and Skeletal Tissues19
- Ch. 7 The Skeleton11
- Ch. 8 Joints7
- Ch. 9 Muscles and Muscle Tissue26
- Ch. 10 The Muscular System26
- Ch. 11 Fundamentals of the Nervous System and Nervous Tissue23
- Ch. 12 The Central Nervous System26
- Ch. 13 The Peripheral Nervous System and Reflex Activity28
- Ch. 14 The Autonomic Nervous System18
- Ch. 16 The Endocrine System26
- Ch. 17 Blood27
- Ch. 18 The Cardiovascular System: The Heart22
- Ch. 19 The Cardiovascular System: Blood Vessels27
- Ch. 20 The Lymphatic System and Lymphoid Organs and Tissues16
- Ch. 21 The Immune System: Innate and Adaptive Body Defenses29
- Ch. 22 The Respiratory System20
- Ch. 23 The Digestive System30
- Ch. 24 Nutrition, Metabolism, and Energy Balance26
- Ch. 25 The Urinary System25
- Ch. 26 Fluid, Electrolyte, and Acid-Base Balance24
- Ch. 27 The Reproductive System23
Marieb, Hoehn7th EditionHuman Anatomy & PhysiologyISBN: 9780805359091Not the one you use?Change textbook
Chapter 18, Problem 2
Total peripheral resistance:
a. is inversely proportional to the length of the vascular bed
b. increases in anemia
c. decreases in polycythemia
d. is inversely related to the diameter of the arterioles
Verified step by step guidance1
Step 1: Understand the concept of total peripheral resistance (TPR). TPR is the resistance to blood flow offered by all of the systemic vasculature, primarily influenced by the diameter and length of blood vessels, and blood viscosity.
Step 2: Recall that TPR is directly proportional to the length of the vascular bed, meaning that as the length increases, resistance increases. Therefore, it is not inversely proportional to length.
Step 3: Consider the effect of anemia and polycythemia on blood viscosity. Anemia decreases blood viscosity, which tends to decrease TPR, while polycythemia increases blood viscosity, which tends to increase TPR.
Step 4: Recognize that vessel diameter, especially of arterioles, has a strong inverse relationship with resistance. According to Poiseuille's law, resistance is inversely proportional to the fourth power of the vessel radius (or diameter), so smaller diameter means higher resistance.
Step 5: Use these principles to evaluate each option: (a) is incorrect because TPR is directly proportional to length; (b) is incorrect because anemia decreases viscosity and thus TPR; (c) is incorrect because polycythemia increases viscosity and TPR; (d) is correct because TPR is inversely related to arteriole diameter.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Total Peripheral Resistance (TPR)
TPR refers to the overall resistance to blood flow offered by the systemic blood vessels, primarily arterioles. It is a key determinant of blood pressure and is influenced by vessel diameter, blood viscosity, and vessel length.
Recommended video:
3:33
Peripheral Nervous System
Relationship Between Vessel Diameter and Resistance
Resistance to blood flow is inversely related to the fourth power of the vessel radius, meaning small changes in arteriole diameter greatly affect TPR. Narrower arterioles increase resistance, while wider arterioles decrease it.
Recommended video:
6:40Relationship Between Blood Flow, Pressure, & Resistance
Effect of Blood Viscosity on Resistance
Blood viscosity, influenced by factors like hematocrit, affects TPR. Anemia (low red blood cells) decreases viscosity and resistance, while polycythemia (high red blood cells) increases viscosity and resistance.
Recommended video:
8:32Altering Resistance in Blood Vessels
Related Practice
Textbook Question
Arterial blood pressure increases in response to:
a. increasing stroke volume
b. increasing heart rate
c. atherosclerosis
d. rising blood volume
e. all of these
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Textbook Question
Which statement does not accurately describe veins?
a. Have less elastic tissue and smooth muscle than arteries.
b. Contain more fibrous tissue than arteries.
c. Most veins in the extremities have valves.
d. Always carry oxygen-poor blood.
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Textbook Question
Which of the following would not result in the dilation of the terminal arterioles and upstream arterioles in systemic capillary beds?
a. A decrease in local tissue O₂ content
b. An increase in local tissue CO₂
c. A local increase in histamine
d. A local increase in pH
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