Term
What are the main structures of the lymphatic system?
What does the lymphatic system do? |
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Definition
lymphatic vessels, lymph nodes
Collect excess tissue fluid and blood proteins lost from blood capillaries to edema
Return tissue fluid and blood proteins to bloodstream |
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Term
| What is and what causes elephantiasis? |
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Definition
| Parasitic worm that lives in lymph vessels blocks them preventing return of excess tissue fluid to blood, accumulates in tissues->edema |
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Term
lymphatic vessels collect -
carry -
flow- |
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Definition
lymph from loose CT
Carry fluid to great veins in neck
One way flow; fluid flows only toward heart |
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Term
| Order the Lymphatic Vessels: |
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Definition
1. Lymph capillaries
2. Lymphatic collecting vessels
3. Lymph Trunks
4. Lymph Ducts |
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Term
Describe:
Lymph capillaries |
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Definition
1. smallest, first recieve lymph
Located near blood capillaries
simple squamous endothelium
receive tissue fluid from CT around blood capillaries
closed at ends: minivalve flaps open to allow fluid to enter
high permeability allows uptake of fluid and entrance of barteria, viruses, cancer cells |
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Term
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Definition
specialized lymphatic capillaries
in villi of small intestines
receive digested fats absorbed from small intestine
fatty lymph= chyle (white) |
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Term
| Describe lymphatic collecting vessels: |
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Definition
accompnay distributing arteries and their veins
composed of the same 3 tunics as blood vessels; much thinner walls, contain more valves- helps direct the flow of lymph one way |
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Term
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Definition
bulging skeletal muscles
pulsing nearby arteries
tunica media of the lymph vessels
random movements |
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Term
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Definition
cleanse the lymph of pathogens
human body contains apprx 500
lymph nodes are organized in clusters |
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Term
| How are lymph nodes organized in clusters: |
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Definition
at base of limbs:
1. axillary nodes (armpit)
2. inguinal nodes (upper thigh)
Along descending aorta- aortic nodes
Along major blood vessels in neck=cerviacal nodes
IN mediastinum= tracheobronchial nodes
Along iliac artery in pelvis- iliac nodes |
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Term
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Definition
lymphatic collecting vessels converge
5 major trunks |
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Term
| What are the 5 major lymph trunks? |
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Definition
1. lumbar trunks- receive lymph from lower limbs
2. intetinal trunk- receives chyle from digestive organs (cisterna chyli-bulubous swelling, located at the union of lumbar and intestinal trunks)
3. Bronchomediastinal trunks- collects lymph from thoracic viscera
4. Subclavian trunks- receive lymph from upper limbs and thoracic wall
5. Jugular trunks- drain lymph from head and neck |
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Term
| What are the lymph ducts? |
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Definition
1. Thoracic duct- ascends along vertebral bodies, empties into venous circulation, junction of left internal jugular and left subclavian veins, drains 3/4 of body
2. Right lymphatic duct- empties into right jugular and subclavian veins, drains head and upper right thorax |
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Term
Our body is constantly --
What is our bodies non-specific defense:
Specific defence: |
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Definition
under attack of bacteria, yeast, fungi, viruses, cancer cells
Non-specific= inflamation (granulocytes and macrophages)
Specific= lymphocytes, recognize specific foreing molecules=antigens |
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Term
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Definition
1. B lymphocytes- become plasma cells that secrete antibodies and stimulate macrophages
2. Cytotoxic T lymphocytes- destroy antigen bearing cells
3. Helper T lymphocytes- secrete molecules which causes T and B lymphocytes to divide and differentiate to fully active immune cells
HIV invades and destroys helper T cells |
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Term
| Stage One of lymphocyte activation: |
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Definition
| lymphocytes originate in bone marrow from blood stem cells |
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Term
| Stage two of lymphocyte activation: |
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Definition
some travel to thymus gland to become T lymphocyte, thymic hormone induce differentiation into different T cells
-Some stay i bone marrow to become B lymphocyte (B=bursa of fabricius, birds)
Cells gain a membrane proteins sequence that recognizes a unique antigen
-before encountering the foreign molecule 100s of lymphocyte are assigned a different antigen so many that chances are at least one can recognize any possible antigen configuration
They are Immunocompetent, but naive (not exposed to antigen yet) |
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Term
| Stage 3 of lymphocyte activation: |
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Definition
begins after exposure to antigen
antigen has to presented to T lymphocytes
-dendritic cells (specialized macropages phagocytose foreing invaders and inert antigens into their mebranes; only then can T cells regognize the antigen
B lymphocyte can recognize antigens
T helper cells stimulte T and B cells
-B cells become plasma cells
Each unique lymphocyte repeatedly divides to form many clones, each able to respond to same antigen as parent lymphocyte |
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Term
| Activating T or B cells produce: |
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Definition
1. effector lymphocyte- short lived, attack immediately
2. Memory lymphocyte- wait until body encounters their antigen again, basis of acquired immunity |
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