Structure, Functions and Common Disorders of Lymphatic System
Session 37: Structure, Functions and Common Disorders of Lymphatic System
Total Session Time: 120 minutes+ 60 minutes assignment
Prerequisites
Students Learning Tasks
By the end of this session students are expected to be able to:
Resources Needed:
SESSION OVERVIEW
|Step |Time |Activity/ |Content |
| | |Method | |
|1 |05 minutes |Presentation |Introduction, Learning Tasks |
|2 |30 minutes |Presentation |Definition and Organization of |
| | |Brainstorming |Lymphatic System |
|3 | |Presentation |Structures of the Lymphatic System |
| |25 minutes |Small Group | |
| | |Discussion | |
|4 |20 minutes |Presentation |Functions of the Lymphatic System |
| | |Buzzing | |
|5 |20 minutes |Presentation |Common Disorders of the Lymphatic |
| | |Brainstorming |System |
|6 |05 minutes |Presentation |Key Points |
| 7 |05 minutes |Presentation |Evaluation |
|8 |10 minutes |Presentation |Take home assignment |
SESSION CONTENTS
STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)
READ or ASK students to read the learning tasks and clarify
ASK students if they have any questions before continuing
STEP 2: Definition and Organization of Lymphatic System (30minutes)
|Activity: Brainstorming (5 minutes) |
| |
|Ask students to brainstorm on the following question: |
| |
|What is lymphatic system? |
| |
|ALLOW few students to respond |
| |
|WRITE their responses on the flip chart/ board |
| |
|CLARIFY and SUMMARISE by using the content below |
maintain the body’s fluid balance, cleanse the body fluid of foreign
matter and provide immune cells for defence.
o Lymph, the fluid that the system collects from the interstitial spaces
of the tissue and returns to the bloodstream.
o Lymphatic plexuses, networks of small lymphatic vessels, lymphatic
capillaries, that originate in the extracellular spaces of most
tissues.
o Lymphatic vessels (lymphatics), a nearly body wide network of thin-
walled vessels with abundant valves, originating from lymphatic
plexuses along which lymph nodes are located.
o Lymph nodes, small masses of lymphatic tissue through which lymph is
filtered on its way to the venous system.
o Lymphocytes, circulating cells of the immune system that react against
foreign materials.
o Lymphoid tissue, sites that produce lymphocytes, such as that found in
the walls of the digestive tract; in the spleen, thymus, and lymph
nodes; and in myeloid tissue in red bone marrow.
o The lymphoid tissue is primarily involved in immune responses, and
consists of lymphocytes and other white blood cells enmeshed in
connective tissue through which the lymph passes.
o The lymphatic system differs from the circulatory system in that the
lymphatic do not form a closed ring or circuit.
o Instead, begin blindly in the intercellular spaces of the soft tissues
of the body.
o Specialized lymphatic organs are the tonsils, thymus, and spleen.
[pic]
Source: Tortora, G.J (2009). Figure 35.1: The
lymphatic system
STEP 3: Structures of Lymphatic System (25 minutes)
|Activity: Small Group Discussion ( 30 minutes) |
| |
|DIVIDE students into small manageable groups |
| |
|ASK students to discuss on the following question |
|What are the structures of lymphatic system? |
| |
|ALLOW students to discuss for 15 minutes |
| |
|ALLOW few groups to present and the rest to add points not mentioned |
| |
|CLARIFY and SUMMARIZE by using the contents below |
o Masses of lymphoid tissue located in a protective ring under mucous
membranes in the mouth and back of the throat.
o Help protect against bacteria that may invade tissues in the area
around the openings between the oral and nasal cavities.
o They are:
cavity.
o The tonsils serve as the first line of defence from the exterior and
as such are subject to chronic infection (tonsillitis).
o The thymus is located inferior to the thyroid gland.
o In the foetus and infant, the thymus is large and extends under the
sternum
o The thymus hormones are necessary for immunological competence by
enabling the T-cells to participate in the recognition of foreign
antigens and provide immunity.
o This capability of T cells is established early in life and then is
perpetuated by the lymphocytes themselves.
o The new-born’s immune system is not yet fully mature, and infants are
more susceptible to certain infections than are older children and
adults.
o Usually by the age of 2 years, the immune system matures and becomes
fully functional.
o Spleen is located in the left hypochondrium directly below the
diaphragm, above the left kidney and descending colon, and behind the
fundus of the stomach
o It is roughly ovoid
o Is surrounded by a fibrous capsule with inward extensions that
roughly divide the organ into compartments
o Arteries leading into each compartment are surrounded by dense masses
(nodules) of developing lymphocytes
o Near the outer regions of each compartment is tissue called red pulp
made up of fine reticular fibres submerged in blood that comes from
nearby arteries.
o After passing through the reticular meshwork, blood collects in
venous sinuses and then returns to the heart through veins.
STEP 4: Functions of Lymph System (20 minutes)
|Activity: Buzzing (5 minutes) |
| |
|ASK students to pair up and buzz on the following question for 2 |
|minutes |
| |
|What are the functions of lymphatic system? |
|ALLOW few pairs to respond and let other pairs to add on points not |
|mentioned |
| |
|WRITE their response on the flip chart/board |
| |
|CLARIFY and SUMMARIZE by using the content below |
o Maintenance of fluid balance in the internal environment
o Immunity
molecular weight substances which cannot be absorbed by the blood
capillary to be removed from the interstitial spaces.
blood only via lymphatic vessels.
capillaries (lacteals) receive all absorbed fat (chyle) from the
intestine and convey it through the thoracic duct to the venous system.
the protein are produced by immunologically competent cells and/or
lymphocytes and dispatched to the infected area.
important function in the absorption of fats and other nutrients.
the capillaries.
by the blood before it flows out of the tissue.
interstitial fluid would cause massive oedema.
‘drains’ to collect the excess fluid and return it to the venous blood
just before it reaches the heart.
STEP 6: Common Disorder of the Lymphatic System (20 minutes)
|Activity: Brainstorming (5 minutes) |
| |
|Ask students to brainstorm on the following question: |
| |
|What are the common disorders of lymphatic system? |
|ALLOW few students to respond |
| |
|WRITE their responses on the flip chart/ board |
| |
|CLARIFY and SUMMARISE by using the content below |
lymph nodes (also known as lymphadenopathy), swelling due to lymph node
blockage (also known as lymphedema) and cancers involving the lymphatic
system,
o The swollen nodes can sometimes be felt in the neck, underarms and
groin.
o Lymphadenopathy is usually caused by infection, inflammation, or
cancer.
o Infections that cause lymphadenopathy include bacterial infections
such as strep throat, locally infected skin wounds, or viral
infections such as mononucleosis or HIV infection.
o Inflammatory or autoimmune conditions occur when a person's immune
system is active, and can result in enlargement of lymph nodes. This
can happen in lupus.
o Lymphoma is cancer of the lymph nodes.
STEP 7: Key Points (5minutes)
maintain the body’s fluid balance, cleanse the body fluid of foreign
matter and provide immune cells for defence.
vessels, lymph nodes, lymphocytes and lymphoid tissue.
internal environment and immunity
and lymphomas,
STEP 7: Evaluation (5minutes)
Step 8: Assignment (10 minutes)
|Activity: Take Home Assignment (10 minutes) |
| |
|DIVIDE learners in groups or individual. |
| |
|ASK the learners to work on the following assignment |
| |
|Explain structure and functions of lymphatic system |
| |
|ALLOCATE time for learners to do the assignment and submit |
| |
|REFER learners to recommended references |
References
Seeley, R. R., Stephens, T. D., & Tate, P. (2003). Anatomy and Physiology.
New York:
McGraw-Hill.
Shier, A., Butler, J., & Lewis, R. (2004). Hole’s Human Anatomy &
Physiology. New
York: McGraw-Hill.
Thibodeau, G. A., & Patton, K. T. (1999). Anatomy & Physiology. Saint
Louis: Mosby,
Von Hoffman Press, Inc.
Waugh, A., & Grant, A. (2006). Ross and Willson Anatomy and physiology in
Health and
illness. United Kingdom: Churchill Livingstone Elservier.
Scalon, V.C., & Sanders, T. (2007). Essentials of anatomy and physiology
(5th ed.).
Philadelphia, NY: F.A Davis
Tortora, J.G., & Derrickson, B. (2009). Principles of anatomy and
physiology (12th
ed.).Danvers, MA: John Wiley & Sons
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