[PEP] High School Biology, Selective Compulsory Volume 1: The "Immune Outposts" Around Us

When a doctor asks you to open wide and checks your "tonsils" because your throat hurts from a cold, you're standing at the front line of your body's defense system. Together, the tonsils, lymph nodes, spleen, thymus, and bone marrow form the body'simmune organs. They serve not only as the "outposts" and "barracks" where immune cells (such as B cells and T cells) are produced, mature, or stationed, but also as the "battlefields" that defend the body's internal homeostasis.

Core Concept: A Network of Recognition and Regulation

HLA and Identity Tags: Every person's cells have unique "Human Leukocyte Antigens" (HLA) on their surface. This is the key for the immune system to distinguish "self" from "non-self." Inorgan transplantationHLA matching is critical to success.
Immune Homeostasis: The immune system doesn't just defend against external threats; it also clears away aging or damaged cells to maintain internal stability.
Multidimensional Control Network: Growing evidence shows that the nervous, endocrine, and immune systems regulate each other, forming a complex network throughsignaling molecules.Humoral regulation and neural regulation are closely linked and work together to regulate all life activities of the body.

Tactical Drills: Specific Immunity

Inside these outposts, humoral immunity (where B cells produce antibodies) and cell-mediated immunity (where cytotoxic T cells destroy target cells) work together. As shown in Figures 4-6 and 4-7, when the H3N2 virus invades, the immune surveillance function is activated, and the formation of memory cells prepares the body for future invasions.

Real-World Medical Insight

The China Organ Transplantation Response System uses precise HLA scoring algorithms to ensure the safety and fairness of transplants. This is built on our deep understanding of immune recognition mechanisms.

QUESTION 1

A doctor checks a patient's swollen tonsils. What does this mean in immunological terms? Is it beneficial or harmful to health?

It means the immune organs are actively responding to an infection, and this localized inflammatory response is beneficial for early defense.

It means the immune system has completely collapsed and all lymphatic organs must be removed immediately.

The tonsils are just decorative; swelling has no real immunological significance.

QUESTION 2

For tonsils that become inflamed repeatedly, doctors sometimes recommend removal. The most likely reason is:

To reduce body weight, since the tonsils take up space.

The tonsils have turned from a defense outpost into a hiding place for pathogens (a focus of infection), and the harm outweighs their immune protection.

After removal, the person will never catch a cold again.

QUESTION 3

A person develops an infection in a foot wound, and 5 days later, the right groin lymph nodes become swollen and painful. The mechanism is:

Pathogens travel through lymphatic vessels to the groin lymph nodes, stimulating immune cell proliferation and differentiation.

This is because the nervous system directly causes the lymph nodes to enlarge as a warning signal.

QUESTION 4

Based on knowledge of the immune system components: Cytokines can be synthesized and secreted by immune cells.

True

False

QUESTION 5

True or False: T cells only participate in cell-mediated immunity, and B cells only participate in humoral immunity.

True

False