Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

19. The Blood Vessels

Introduction to Hemodynamics

Anatomy & Physiology

19. The Blood Vessels

Introduction to Hemodynamics

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3:04 minutes

Problem 30

Textbook Question

Mrs. Rees is brought to the emergency room after being involved in an auto accident. She is hemorrhaging and has a rapid pulse that can barely be felt, but her blood pressure is still within normal limits. Describe the compensatory mechanisms that are maintaining her blood pressure in the face of blood loss.

Verified step by step guidance

Recognize that Mrs. Rees is experiencing hemorrhagic shock, which is a condition where there is significant blood loss leading to decreased blood volume.

Understand that the body compensates for blood loss by activating the sympathetic nervous system, which releases catecholamines like adrenaline to increase heart rate and contractility, helping maintain cardiac output.

Acknowledge that vasoconstriction occurs in peripheral blood vessels, which increases systemic vascular resistance and helps maintain blood pressure despite reduced blood volume.

Note that the renin-angiotensin-aldosterone system (RAAS) is activated, leading to the release of angiotensin II, which causes vasoconstriction and stimulates aldosterone release to promote sodium and water retention, increasing blood volume.

Consider that antidiuretic hormone (ADH) is released to promote water reabsorption in the kidneys, further aiding in maintaining blood volume and pressure.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Compensatory Mechanisms

Compensatory mechanisms are physiological responses that help maintain homeostasis in the body during stress or injury. In the context of hemorrhage, these mechanisms include increased heart rate, vasoconstriction, and fluid retention, which work to stabilize blood pressure despite significant blood loss.

Baroreceptor Reflex

The baroreceptor reflex is a critical feedback loop that helps regulate blood pressure. Baroreceptors located in the carotid arteries and aorta detect changes in blood pressure and send signals to the central nervous system, which can trigger responses such as increased heart rate and vascular resistance to maintain adequate blood flow.

Hormonal Responses

Hormonal responses, particularly the release of catecholamines (like adrenaline) and hormones such as aldosterone and antidiuretic hormone (ADH), play a vital role in compensating for blood loss. These hormones promote vasoconstriction, increase heart rate, and enhance fluid retention, all of which help to sustain blood pressure during hemorrhagic events.

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Arterial blood pressure increases in response to:

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b. increasing heart rate

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d. rising blood volume

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Textbook Question

More than one choice may apply.

An increase in BP would be caused by all of the following except

a. Increase in SV

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Mr. Grimaldi was previously diagnosed as having a posterior pituitary tumor that causes hypersecretion of ADH. He comes to the clinic regularly to have his blood pressure checked. Would you expect his blood pressure to be chronically elevated or depressed? Why?

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The carotid sinus contains:

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Textbook Question

Which of the following would produce a decrease in blood pressure?

a. Increased cardiac output

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The two pressures within the systemic arterial circuit are the_____ pressure and _____ pressure. The difference between these two pressures is the_____ pressure.

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