14.2.1.2 Increased susceptibility to infections

• What are pathogens?

  Germs that cause disease
• How does the immune system function in the body?

  It protects the body from infections
• What are antibodies?

  Special proteins that neutralize pathogens
• What does the body release during the stress response?

  Glucocorticoids
• How do glucocorticoids affect the immune system?

  They suppress the immune system's activity
• How does the vagus nerve connect the brain to the immune system in this pathway?

  • Vagus nerve connects the brain (SNS) to the spleen
  • This allows the brain to influence immune responses through the SNS
• Which part of the adrenal gland releases glucocorticoids like cortisol in response to stress?

  Adrenal cortex
• If you wanted to study the detailed structure of a cell in this stress response, which type of microscope would you use?

  Scanning electron microscope
• How do the peripheral blood cells (NK cell, B cell, Monocyte, etc.) respond to the stress response shown in the image?

  They are stimulated by cytokines released during the stress response
• How does the sympathetic nervous system respond to stress in the image?

  • Releases "hard-wiring" sympathetic innervation
  • Stimulates release of norepinephrine and adrenaline
• What are the key effects of stress on the immune system?

  • Reduced production of immune cells
  • Decreased activity of existing cells
  • Interference with communication between cells
  • Weakened ability to fight off pathogens
• What is the role of IL-6 in this antibody-dependent immunity pathway?

  It influences the immune response
• What is the role of the hypothalamus in the stress response shown in the image?

  The hypothalamus releases corticotropin-releasing hormone to stimulate the pituitary gland
• What are the reasons for immunosuppression?

  • Medications after organ transplants
  • Certain diseases like HIV/AIDS
  • Prolonged stress
• How do the different cell types (e.g. macrophage, T cell, brown adipocyte) interact in this antibody-dependent immunity pathway?

  • Macrophages, T cells, and brown adipocytes communicate through signaling molecules like cytokines and chemokines
  • This allows coordination of the immune response
• What types of infections are you more susceptible to when immunosuppressed?

  Colds, flu, and other illnesses
• What happens to the immune system when it is suppressed?

  It can't fight off invaders effectively
• What does the HPA axis release that affects immune function?

  Glucocorticoids (GC)
• What is a direct consequence of stress-induced immune dysfunction?

  Heightened susceptibility to infections
• What is the relationship between stress and immune dysfunction?

  Stress induces immune dysfunction
• What analogy is used to describe the immune system?

  It is like an army defending the body
• What is the role of immune cells?

  To hunt down and destroy infected cells
• What is the name of the lymph node structure shown in the image?

  Lymph node
• How does a strong immune system function against threats?

  • Quickly neutralizes pathogens
  • Keeps the body healthy
• What can happen if severe infections occur due to immune suppression?

  They might require hospitalization
• Why does immune suppression make individuals more vulnerable to illnesses?

  Because the immune system isn't as strong
• How does the microbiome influence the antibody-dependent immunity pathway?

  It stimulates myeloid cell proliferation
• What is the name of the receptor on the ChAT T cell shown in the image?

  ACh
• What is the role of the NA (NKT cells) in this antibody-dependent immunity pathway?

  They activate the immune response
• What are the main components of the antibody-dependent immunity pathway shown in the image?

  • Plasma cell
  • NA (NKT cells)
  • β-AR (Brown adipocyte)
  • ChAT T cell
  • Macrophage
• What are the main components of the adrenal gland shown in the image?

  • Adrenal cortex
  • Adrenal medulla
• Why is extra support needed for immunosuppressed individuals?

  They need help to protect against infections
• What is the purpose of the immune system suppression during stress?

  To prioritize immediate danger responses
• What is the role of the HPA-axis in this antibody-dependent immunity pathway?

  • The HPA-axis regulates the immune response, likely through the release of glucocorticoids
• What is the name of the cell type shown in the center of the image?

  Plasma cell
• How do the β3-AR (brown adipocytes) interact with the other components of this antibody-dependent immunity pathway?

  They communicate with the immune cells through signaling molecules
• What is the effect of a suppressed immune system on susceptibility to infections?

  You become more susceptible to infections
• What is the definition of immunosuppression?

  When the immune system isn't working well
• What are the two main pathways by which stress affects immune function?

  HPA axis and SNS activation
• How do antibodies function in the immune system?

  They target and disable invaders