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

16. The Endocrine System

Introduction to the Endocrine System

Anatomy & Physiology

16. The Endocrine System

Introduction to the Endocrine System

Previous problemNext problem

2:50 minutes

Problem 26

Textbook Question

A reticulocyte count indicated that 5% of Tyler's red blood cells were reticulocytes. His blood test also indicated he had polycythemia and a hematocrit of 65%. Explain the connection between these three facts.

Verified step by step guidance

Understand the terms: Reticulocytes are immature red blood cells (RBCs) that are released from the bone marrow into the bloodstream. A reticulocyte count of 5% means that 5% of Tyler's circulating RBCs are immature. Polycythemia refers to an abnormally high number of RBCs, and a hematocrit of 65% indicates that 65% of Tyler's blood volume is composed of RBCs, which is higher than the normal range (typically 38-52% depending on sex and age).

Connect the reticulocyte count to RBC production: A higher-than-normal reticulocyte count suggests that Tyler's bone marrow is producing RBCs at an accelerated rate. This could be a compensatory response to a condition that requires increased oxygen delivery or a reaction to a stimulus like erythropoietin (a hormone that promotes RBC production).

Relate polycythemia to the hematocrit: Polycythemia is characterized by an elevated hematocrit, as seen in Tyler's case (65%). This indicates an excessive number of RBCs in his blood, which can increase blood viscosity and potentially lead to complications like hypertension or clotting issues.

Explain the connection between reticulocyte count and polycythemia: The elevated reticulocyte count suggests that the polycythemia is likely due to increased RBC production by the bone marrow. This could be caused by a primary condition (e.g., polycythemia vera, a bone marrow disorder) or a secondary condition (e.g., chronic hypoxia or increased erythropoietin levels).

Summarize the relationship: Tyler's high reticulocyte count, polycythemia, and elevated hematocrit are interconnected. The high reticulocyte count indicates active RBC production, which contributes to the polycythemia and elevated hematocrit. Further investigation is needed to determine the underlying cause of these findings, such as oxygen levels, erythropoietin levels, or bone marrow function.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

Key Concepts

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

Reticulocyte Count

A reticulocyte count measures the percentage of reticulocytes, which are immature red blood cells, in the blood. An elevated reticulocyte count indicates increased red blood cell production by the bone marrow, often in response to anemia or blood loss. In Tyler's case, a 5% reticulocyte count suggests that his body is attempting to produce more red blood cells, possibly due to the underlying condition of polycythemia.

Polycythemia

Polycythemia is a condition characterized by an increased concentration of red blood cells in the bloodstream, leading to a higher hematocrit level. This can result from various factors, including chronic hypoxia, dehydration, or bone marrow disorders. Tyler's hematocrit of 65% indicates significant polycythemia, which can increase blood viscosity and the risk of complications such as thrombosis.

Hematocrit

Hematocrit is the proportion of blood volume that is occupied by red blood cells, expressed as a percentage. A normal hematocrit range varies by age and sex, but values above 50% are generally considered elevated. In Tyler's case, a hematocrit of 65% suggests severe polycythemia, which, combined with the reticulocyte count, indicates that his body is responding to a condition that necessitates increased red blood cell production.

Watch next

Master Types of Chemical Messengers with a bite sized video explanation from Bruce Bryan

Start learning

Related Videos

Related Practice

Multiple Choice

Testosterone is categorized as which of the following types of hormones?

views

Multiple Choice

The low blood potassium levels seen among people with eating disorders may cause which of the following complications?

views

Multiple Choice

Which of the following correctly matches an anterior pituitary hormone with its primary target tissue?

views

Textbook Question

Amanda Healy, a young woman with severe vaginal bleeding, is admitted to the emergency room. She is three months pregnant, and the physician is concerned about the volume of blood she is losing.

What type of transfusion will probably be given to this patient?

Which blood tests will be performed before starting the transfusion?

views

Multiple Choice

For a nerve impulse to travel from one neuron to another, the signal must be transmitted across a synapse. At the synapse, the axon releases a neurotransmitter that then diffuses across the synapse and activates receptors on the subsequent dendrite. While this is an example of a nervous signal using a neurotransmitter, the action of neurotransmitter at a synapse is also sometimes considered an example of what other type of signaling?

Epinephrine (also known as adrenaline) is produced by your adrenal cortex during stressful situations. The adrenal cortex is part of the adrenal gland, located just superior to the kidneys. One of the targets for adrenaline is the heart, where it increases the heart rate. Based on this description, what type of signaling molecule is adrenaline?

Between the statements below, which one correctly describes a significant difference between how the endocrine and nervous systems function?

True or False: if false, choose the answer that best corrects the statement.

Target cells can be defined as cells that possess a receptor that binds a particular hormone.