Innate vs Adaptive Immunity
which system has immune memory
adaptive immunity
Which cell mediates humoral immunity
B cells
where does lymph originate from?
interstitial fluid from blood plasma
Name 1 primary lymphoid organ
bone marrow or thymus
which system has many receptor types per cell
innate leukocytes
where do B & T cells mature respectively
Bone marrow (B), Thymus (T).
2 structural features of lymphatic capillaries that allow fluid entry
thin, overlapping endothelial cells that act as 1 way openings
Anchoring filaments allow vessels to open when tissue pressure increases.
name 2 secondary lymphoid organs
lymph nodes & spleen
state 1 genetic difference between innate & adaptive receptors
adaptive receptors are formed by multiple gene fragments; innate receptors encoded by single gene
State TWO functional differences between B and T cells.
how does the lymph move without a pump??
Driven by skeletal muscle contraction, vessel compression, and one-way valves; larger vessels have smooth muscle contraction.
what happens in secondary lymphoid organs
Adaptive immune responses begin:
Lymph nodes: tissue surveillance
SPleen: blood surveillance
Antigen encounter, lymphocyte activation, clonal expansion, and initiation of adaptive responses.
Explain how the lymphatic system contributes to homeostasis (fluid balance)
lympathic system collects excess interstitial fluid that does not return to the blood during capillary exchange (approximately 3 L per day) and returning it to the venous circulation at the subclavian veins, thereby maintaining blood volume and preventing tissue oedema.
Explain why lymph nodes are ideal sites for immune activation
They bring together antigens from tissues via lymph and naïve lymphocytes from blood, with organised B- and T-cell regions that maximise efficient antigen presentation and activation.
Lymphatic system defends the body by delivering and concentrating antigens from tissues into lymph nodes.
2 different entry routes converge in the lymph node:
1. Antigens enter from the tissues via lymph
2. Lymphocytes enter from the blood
The lymph node is therefore a meeting point for antigens and immune cells/lymphocytes
Compare the lymphatic system with the circulatory system. How do they differ? How do they interact together?
Fluid: Blood vs Lymph (from ISF)
Circuit: Closed vs one-way, open ended
Driving force: Pump by heart under pressure vs no central pump
Vessel walls: continuous thick, vs thin walls with overlapping endothelial flaps
Flow pathway: arteries -> capil -> veins VS lymp capils -> vessels -> nodes -> ducts
Main role: Deliver O2 & nutrients, remove wastes VS return excess fluid; immune surveillance
Filtration sites: kidneys, liver, spleen vs LYMPH nodes
Pressure: high v low
valves: in veins vs throughout vessels to prevent backflow
CVS: Closed, high-pressure system -> transports blood using the heart (pump) vessels & fluid, while the lymphatic system is a low-pressure, one-way system that returns excess interstitial fluid to the circulation and supports immune surveillance.
Interact at the capillary level where fluid leaves blood to enter tissues, and the lymphatic system collects the excess and returns it to the venous circulation at the subclavian veins, maintaining blood volume and enabling immune monitoring.