Lymphatic System Flashcards
Structure of the lymphatic system
- Open circulatory system (has a start and end point rather than being continuous)
- Contains lymph fluid, lymph vessels, lymph glands, spleen, thymus, bone marrow, tonsils, adenoids, Peyer’s patches
Compare the lymphatic system with the CVS
- Both are circulatory systems as they transport fluid around the body
- CVS = closed (continuous loop) whereas lymphatic = open (has a start and end point)
- CVS = pump (heart) whereas lymphatic = no pump (other factors e.g. changes in
thoracic pressure and muscle contractions) - CVS = blood filtered by kidneys whereas lymphatic = lymph filtered by lymph nodes
What is A? Is it primary or secondary lymphatic tissue?
Adenoid - secondary
What is B? Is it primary or secondary lymphatic tissue?
Tonsils - secondary
What is C? Is it primary or secondary lymphatic tissue?
(Cervical) lymph node - secondary
What is D? Is it primary or secondary lymphatic tissue?
Thymus - primary
What is E and what is its function?
Thoracic duct
- Drains lymph from: the legs, abdominopelvic cavity, left arm and left halves of the thorax, head and neck
What is F? Is it primary or secondary lymphatic tissue?
Peyer’s patches - secondary
What is G? Is it primary or secondary lymphatic tissue?
Bone marrow - primary
What is H? Is it primary or secondary lymphatic tissue?
Spleen - secondary
What are lymphocytes and where are they formed and matured?
- Type of leukocyte (WBC), B cells produce antibodies to destroy pathogens whereas T cells directly destroy pathogens by releasing cytotoxic chemicals
- Both B & T lymphocytes are produced in bone marrow but B cells mature in bone marrow and T cells mature in the thymus.
Primary lymphoid tissue vs secondary lymphoid tissue
- Primary: site of lymphocyte formation and maturation (bone marrow and thymus)
- Secondary: sites where lymphocytes interact with and filter extracellular fluids such as plasma, tissue fluid and lymph (lymph nodes, spleen, tonsils, adenoids, Peyer’s patches)
Describe the structure and function of bone marrow
- S = primary lymphoid tissue inside spongy bone
- F = produce B & T lymphocytes, mature B lymphocytes (lymphoblast>lymphocyte)
What is the function of the thymus?
To mature T lymphocytes
Difference between lymph, tissue fluid and plasma
- Tissue fluid = leaked out of blood into surrounding tissues due to increased pressure
- Lymph = within lymph vessels
- Plasma = in blood
Structure and function of lymph
- S = clear tissue fluid that has been collected by the lymphatic system
- F = transport fats and proteins, transport lymphocytes, transport of pathogens to L/N
Functions of tissue fluid
- To supply cells with a stable environment
- To provide tissues with nutrients e.g. O2
Function of plasma
- Transport nutrients and wastes around the body via the blood
- Absorb/give off heat e.g. evaporation (sweat) for thermoregulation)
State 4 ways in which lymph moves through the lymphatic system
- One-way valves in lymphatic vessels prevent backflow of lymph and promote unidirectional flow
- Skeletal muscle contractions and relaxations (milking action) push lymph through
- Changes in thoracic pressure during inspiration and expiration (respiratory system)
- Smooth muscle lining vessel walls contracts and relaxes to push lymph through > peristalsis
State the pathway of fluid through the lymphatic system
- Excess tissue fluid is collected from venules, capillaries and arterioles by lymph capillaries
- Lymph transported through afferent vessel to L/N where it is filtered, lymph exits L/N via efferent vessel
- Clean lymph returned to CV system via thoracic duct
Describe 4 features of lymph capillaries and how they allow them to achieve their function
- Thin walls > can easily collect excess tissue fluid from CV system
- Overlapping epithelial cells which creates gaps > allows tissue fluid to move into capillary and prevents backflow out of capillary
- Interlaced with venules, arterioles, CV capillaries > easy access to collect tissue fluid
- Closed at one end > creates open circulatory system
Describe 2 features of lymph vessels and how they allow them to achieve their function
- Valves prevent backflow of lymph out of vessel
- Larger lumen than capillaries > allows them to transport lymph from capillaries to ducts
Function of the right lymphatic duct
Drains lymph from: the right arm and the right halves of the thorax, head and neck
Describe the structure and function of lymph nodes
- S = small clusters of specialised 2ndary lymphoid tissue that contain large amounts of leukocytes, located along lymph vessels
- F = filter lymph fluid by destroying and removing foreign particles (e.g. pathogens/dead cells) before it is returned to the CV system
Name the 3 main locations of lymph nodes
Groin (inguinal), armpit (axillary) and neck (cervical)
Describe the structure and function of the spleen
- S = structure containing red and white pulp, located in the L hypochondriac abdominal region
- F = filters blood: contains WBC that destroy pathogens in the blood
- also removes old RBC (CV FUNCTION, NOT LYMPHATIC)
Describe the structure and function of tonsils and adenoids
- S = fleshy pads, tonsils found in the back of the throat, adenoids found at the top of the throat
- F = destroy foreign particles or pathogens that have been inhaled/ enter through the pharynx
Describe the position of adenoids in relation to tonsils
Adenoids are posterior to tonsils
Describe the structure and function of Peyer’s patches
- S = bundle of lymphatic tissue found in the small intestine
- F = destroy swallowed/ingested foreign particles or pathogens
Name the 2 types of MALT in the lymphatic system
- NALT (nasal-associated lymphoid tissue): tonsils, adenoids
- GALT (gut-associated lymphoid tissue): Peyer’s patches
3 functions of the lymphatic system
- Collect excess tissue fluid from between cells and return it to CV system
- Facilitate immune response through producing and maturing lymphocytes for specific immunity, and filtering/destroying foreign particles
- Absorb fat from the digestive system and transport it to the CV system
Structure and function of lacteal
- S = specialised lymphatic capillary found in the villi of the small intestine
- F = absorbs digested fats/lipids from food
Explain how digested fat enters the bloodstream
- Once food is ingested and then digested by the stomach and duodenum, it moves to the small intestine where the lacteal in the villi absorbs the fat
- Lipids are transported to the CV system via the thoracic duct, then the CV system transports lipids around the body via the blood.
Describe 4 ways to maintain a healthy lymphatic system
- Drink plenty of water to ensure viscosity of fluids in body
- Exercise regularly to increase circulation of lymph (milking action of skeletal muscles)
- Balanced diet (decreased fat/adipose tissue promotes circulation)
- Get a massage/lymph drainage therapy to promote circulation
Lymph/o
Axill/o
Lymph fluid
Armpit
Lymphaden/o
Lymphangi/o
Lymph node (gland)
Lymph vessel
Leuk/o
Appendic/o
White
Appendix
Thromb/o
Adenoid/o
Clot
Adenoids
Splen/o
Thym/o
Spleen
Thymus gland
Myel/o
Aden/o
Bone marrow/spinal cord
Gland
