Body system

Immune & Lymphatic Anatomy Diagrams

Labeled diagrams of the immune and lymphatic systems — lymph nodes, the spleen, thymus, lymphatic vessels, and the cells of the innate and adaptive immune response — for immunology teaching and revision.

The immune system is a network of organs, vessels, and cells rather than a single structure, which makes it harder to picture than the heart or the lungs. The lymphatic organs — lymph nodes, spleen, thymus, tonsils, and the mucosal lymphoid tissue — are where immune cells are produced, mature, and encounter antigen. The lymphatic vessels return interstitial fluid to the bloodstream and carry antigen from the tissues to the nodes. The cells themselves — neutrophils, macrophages, dendritic cells, B and T lymphocytes — circulate between all of these.

The diagrams on this page start with the organs, because that is what students can see and locate, and then move to the cellular level. A lymph node in cross-section shows where B cells and T cells sit and why swelling means the node is doing its job. The spleen shows the division between red pulp, which filters blood, and white pulp, which mounts immune responses. The T cell drawing is the entry point for the adaptive response and links to the signalling and activation diagrams in the template library.

Because immunology is taught as much through process as through anatomy, each figure below is designed to sit alongside a mechanism diagram — antigen presentation, T cell activation, the complement cascade — so a lecture can move from "where" to "how" without changing visual style.

Diagrams in this system

What each diagram shows and how to teach with it

Lymph node

A lymph node in cross-section with the capsule, subcapsular sinus, cortex containing follicles and germinal centres, the paracortex, and the medulla. Afferent vessels enter across the convex surface; the efferent vessel leaves at the hilum.

In the lecture

Use this to explain what a lymph node is for and why it enlarges. Antigen arrives through the afferent lymphatics, dendritic cells present it in the paracortex where T cells sit, and B cells in the follicles proliferate into germinal centres when they respond — which is the swelling a patient can feel. This figure pairs naturally with the antigen presentation and T cell activation diagrams.

Spleen

The spleen in its characteristic shape, with the hilum and splenic vessels, and the internal division into red pulp and white pulp indicated.

In the lecture

The point to make is that the spleen has two jobs in one organ. Red pulp filters the blood, removing old red cells and encapsulated bacteria; white pulp is lymphoid tissue arranged around arterioles and mounts responses to blood-borne antigen. That dual role is why splenectomy patients need vaccination against encapsulated organisms, which is a useful clinical anchor for a basic-science lecture.

T cell

A T lymphocyte with its lobulated nucleus and surface T cell receptors, drawn in the same style as the antigen-presenting cell and receptor diagrams in the template library.

In the lecture

Use this as the starting figure for the adaptive immune response. It introduces the T cell receptor as the structure that recognises peptide on MHC, which is the hinge of the whole system. From here a lecture moves to the antigen presentation diagram (how the peptide gets there) and the T cell activation diagram (what happens next). Keeping the drawing style consistent across those three figures is what makes the sequence readable on a slide.

Frequently asked questions