BIOS 255 Week 4 Lymphatic System
Student Name
Chamberlain University
BIOS-255: Anatomy & Physiology III with Lab
Prof. Name
Date
BIOS 255 Week 4 Lymphatic System Learning Objectives
Overview and Functions of the Lymphatic System
The lymphatic system plays a vital role in maintaining homeostasis and immune defense. It is composed of lymph, lymphatic vessels, lymphatic tissues, and lymphatic organs that are distributed throughout the body. This system supports fluid balance by draining excess interstitial fluid, aids in the absorption and transport of dietary lipids from the gastrointestinal tract into the bloodstream, and contributes to immune surveillance by producing and circulating lymphocytes. Approximately 30 liters of fluid filter from blood capillaries into tissues each day, but only 27 liters reenter the venous circulation. The remaining 3 liters are recovered by the lymphatic system and returned to the blood, preventing edema and promoting fluid balance (Marieb & Hoehn, 2022).
Lymphatic capillaries, which are present alongside blood capillary networks, collect interstitial fluid that contains waste products, pathogens, and debris. This fluid, now called lymph, moves through progressively larger lymphatic vessels and passes through lymph nodes, where immune cells filter harmful substances. The system ultimately returns lymph to the circulatory system through the thoracic duct or the right lymphatic duct.
Assignment Instructions
Part 1: Interactive Lab via Anatomy.TV
To complete this part of the lab, students are instructed to explore interactive sections on Anatomy.TV by accessing the following:
- Resources Tab > Library > Library Resources-Database AZ > Anatomy.TV
- Select the Lymphatic System and Immunity title and complete all sections under:
- Introduction
- Vessels and Circulation
- Organs and Tissues
As students navigate through these modules, they must record observations and answers in the lab report provided.
Part 2: Lymphatic System Lab Report
Below is a detailed rephrased version of the lab report, with added explanations and enhanced content:
| Question | Answer |
|---|---|
| 1. What are the four major components of the lymphatic system? | The lymphatic system includes the following key components: • Lymph – a clear fluid rich in white blood cells, derived from interstitial fluid.• Lymphatic vessels – a network of conduits that transport lymph.• Lymphatic tissues – connective tissues populated by immune cells, mainly lymphocytes.• Lymphatic organs – specialized structures like the spleen and lymph nodes involved in immune functions. |
| 2. What are three primary functions of the lymphatic system? | • Immune surveillance – Detects and fights pathogens.• Fluid recovery – Returns excess tissue fluid to the bloodstream.• Lipid transport – Facilitates the absorption and transport of dietary fats from the small intestine into the blood. |
| 3. Name three secondary lymphoid organs. | • Lymph nodes• Spleen• Tonsils |
| 4. List the three tonsils and their anatomical locations. | • Pharyngeal (Adenoid) tonsil – Positioned in the nasopharynx behind the nasal cavity.• Palatine tonsils – Located on each side of the oropharynx.• Lingual tonsils – Found at the base of the tongue. |
| 5. Identify the labeled structures from the lymphatic capillaries diagram. | A. ArterioleB. Lymphatic capillaryC. Anchoring filamentsD. Lymphatic capillary pore (lumen)E. Lymphatic endothelial cell |
| 6. How do the intestines contribute to lymphatic function? | • The small intestine contains specialized lymphatic vessels known as lacteals, which absorb dietary fats too large for blood capillaries.• These fats, packaged as chyle, are transported by intestinal trunks and eventually drain into the thoracic duct for return to circulation. |
| 7. Describe the structure and function of the thoracic duct. | The thoracic duct is the largest lymphatic vessel, measuring about 38–45 cm. It gathers lymph from the entire left side of the body and areas below the diaphragm on the right side. It empties into the junction of the left subclavian and internal jugular veins, completing the return of lymph to venous circulation. |
| 8. What are the two mechanisms responsible for lymph movement? | • Skeletal muscle pump – Muscle contractions compress lymphatic vessels, pushing lymph forward.• Respiratory pump – Breathing movements create pressure changes that help draw lymph toward the thoracic cavity. |
| 9. What happens clinically when the spleen is surgically removed? | Splenectomy increases vulnerability to infections, particularly those caused by encapsulated bacteria, as the spleen plays a vital role in filtering blood and initiating immune responses. |
| 10. How does the skeletal system aid lymphatic circulation? | When skeletal muscles contract, they compress adjacent veins and lymphatic vessels. This pressure propels blood and lymph through their respective valves, encouraging unidirectional flow. Muscle relaxation can lead to temporary backflow, but valves prevent reverse movement, ensuring efficiency. |
Grading Rubric
| Task | Points |
|---|---|
| Part 1: Lab activities | 15 |
| Part 2: Lab report | 15 |
| Total | 30 |
References
Marieb, E. N., & Hoehn, K. (2022). Human Anatomy & Physiology (11th ed.). Pearson Education.