D313 Lab 12 The Lymphatic System

D313 Lab 12 The Lymphatic System

Student Name

Western Governors University

D313 Anatomy and Physiology II with Lab

Prof. Name:

Date

Lab 12 The Lymphatic System

BIO202L
Student Name: Kafayat Anifowose
Access Code: AC-P1ZZ0N

Prelab Questions

1. The experiments in this lab cover the lymphatic system. Provide a brief overview of this system. Include a discussion on the structures involved, its purpose and the cells involved.

The lymphatic system is a complex network that plays a vital role in maintaining fluid balance and supporting immune defense. It comprises several key structures, including lymph nodes, lymphatic vessels, the spleen, tonsils, and thymus gland. Lymph nodes act as filtration sites for lymph fluid, trapping pathogens and facilitating immune responses. The spleen filters blood, removing old or damaged red blood cells and storing platelets. Tonsils and the thymus contribute to regulating immune functions, with the thymus being critical for the maturation of T lymphocytes. Lymphocytes, particularly B cells and T cells, are crucial immune cells within this system, defending the body against infections. Overall, the lymphatic system is essential for waste removal, fluid homeostasis, and providing immune surveillance (Abbas et al., 2020).

EXPERIMENT 1: EXAMINING THE MICROSCOPIC ANATOMY OF THE LYMPHATIC SYSTEM

Introduction Questions

1. In this experiment, you will review slides containing cells from lymph nodes and from the spleen. Describe the specific functions of these tissues. Are they similar or different? How?

Lymph nodes primarily function as filters for lymph fluid, enabling immune cells to encounter and respond to foreign antigens. In contrast, the spleen serves as a blood filter, removing aged red blood cells, storing platelets, and participating in systemic immune reactions within the bloodstream. While both organs contribute to immunity, lymph nodes focus on monitoring lymphatic fluid and initiating localized immune responses, whereas the spleen manages blood quality and systemic immune defense. Their shared role in filtering fluids is complemented by their distinct operational environments and specific immune activities (Janeway et al., 2001).

Data and Observations

Label the arrows in the following two slides:

Results and Discussion

1. Are there more afferent or efferent vessels attached to a lymph node? What is the functional purpose of this?

Lymph nodes have a greater number of afferent vessels than efferent vessels. This design ensures that lymph fluid enters through multiple pathways, allowing it to be exposed extensively to immune cells within the node. The fewer efferent vessels control the outflow, thus prolonging the time lymph spends in the node for filtration and immune activation, enhancing immune surveillance and response efficiency (Kumar et al., 2018).

2. What structural similarities did you observe between the lymph node and spleen?

Both the lymph node and spleen are encapsulated, spherical organs containing an internal framework that facilitates fluid movement and filtration. Each organ has distinct compartments—such as the cortex and medulla in lymph nodes and the red and white pulp in the spleen—that enable specialized immune and filtration functions. This architectural similarity supports their shared role in maintaining immune defense and fluid homeostasis (Mescher, 2016).

EXPERIMENT 2: VIRTUAL MODEL – THE LYMPHATIC SYSTEM

Introduction Questions

1. In what areas are lymph nodes clustered? Why is this desirable?

Lymph nodes cluster in strategic locations where major blood vessels converge, including the neck (cervical region), armpits (axillary region), and groin (inguinal region). These concentrations enable efficient filtration of lymph fluid coming from extensive areas of the body, providing focused sites for immune surveillance. Such positioning enhances the ability of the immune system to rapidly detect and respond to pathogens or abnormal cells circulating in these regions (Ganong, 2016).

2. Explain how the flow of lymph is controlled through lymphatic vessels.

The movement of lymph through lymphatic vessels is regulated by several mechanisms. These include rhythmic contractions of smooth muscle within the vessel walls, the presence of one-way valves that prevent backflow, respiratory movements, and external compression by surrounding skeletal muscles. Together, these processes maintain unidirectional lymph flow toward the venous circulation, compensating for the lack of a central pump like the heart (Tortora & Derrickson, 2018).

Data and Observations

Results and Discussion

EXPERIMENT 3: FETAL PIG DISSECTION – THE LYMPHATIC SYSTEM

Introduction Questions

1. Consider Step 7 of the procedure. Why do you think the procedure is specifying these specific regions?

The cervical (neck), axillary (armpits), and inguinal (groin) regions are highlighted because they contain dense clusters of lymph nodes critical for lymph filtration. These nodes act as sentinel sites where lymph fluid is screened for pathogens or abnormal cells. Investigating these areas allows for comprehensive assessment of immune function and helps detect systemic infections or diseases within the lymphatic system (Ross & Pawlina, 2015).

2. Consider the organ observed in Step 8. Do humans have this same organ? Research the answer to this question and discuss below.

Humans possess a thymus gland similar to that observed in fetal pigs. The thymus is a primary lymphoid organ located in the upper chest, responsible for the maturation and differentiation of T lymphocytes, which are vital for adaptive immunity. Though it involutes and decreases in size with age, the thymus continues to contribute to immune system maintenance throughout life (Kumar et al., 2018).

Data and Observations

Insert a high-resolution photo of the fetal pig with clearly visible lymphatic organs and student identification as per instructions.

Results and Discussion

1. What observations did you make regarding the lymphatic system of the fetal pig?

During the dissection of the fetal pig, identifying lymphatic structures proved more challenging than locating other organ systems. While the spleen and thymus were relatively easy to identify due to their size and distinct appearance, the lymphatic vessels and nodes were more elusive because of their small size and translucency. This difficulty highlights the delicate nature of lymphatic tissues and emphasizes their intricate distribution throughout the body. The overall organization of the lymphatic system in the fetal pig parallels that of humans, reinforcing the model’s value for anatomical study. Observations confirmed the presence of lymphatic structures essential for immune function, including vessels with valves and lymph nodes in expected anatomical locations (Mescher, 2016).

2. Compare and contrast the vessels of the lymphatic system and the circulatory system.

Both the lymphatic and circulatory systems utilize vessels to transport fluids essential for physiological functions. However, the circulatory system comprises arteries and veins that circulate blood, pumped by the heart, whereas the lymphatic system consists of lymphatic vessels that carry lymph fluid without a central pump. Unlike veins, lymphatic vessels contain one-way valves that ensure lymph flows unidirectionally toward the thoracic duct and ultimately the bloodstream. Additionally, lymphatic flow depends largely on skeletal muscle contractions and external forces rather than cardiac output, distinguishing its fluid dynamics from the circulatory system (Tortora & Derrickson, 2018).

References

• Abbas, A. K., Lichtman, A. H., & Pillai, S. (2020). Cellular and Molecular Immunology (9th ed.). Elsevier.

• Ganong, W. F. (2016). Review of Medical Physiology (25th ed.). McGraw-Hill.

D313 Lab 12 The Lymphatic System

• Janeway, C. A., Travers, P., Walport, M., & Shlomchik, M. J. (2001). Immunobiology (5th ed.). Garland Science.

• Kumar, V., Abbas, A. K., Aster, J. C. (2018). Robbins Basic Pathology (10th ed.). Elsevier.

• Mescher, A. L. (2016). Junqueira’s Basic Histology: Text and Atlas (13th ed.). McGraw-Hill.

• Ross, M. H., & Pawlina, W. (2015). Histology: A Text and Atlas (7th ed.). Wolters Kluwer.

• Tortora, G. J., & Derrickson, B. H. (2018). Principles of Anatomy and Physiology (15th ed.). Wiley.