Infections and Blood Immunity

Question 1

Circulating blood is generally considered ________

Answer 1

Sterile

Question 2

What are the main types of microbes causing infection in the blood and what they do.

Answer 2

Sepsis, • presence of toxins or disease-causing bacteria in blood and tissue
Septicemia, also called blood poisoning, infection caused by rapid multiplication of pathogens in the blood

Question 3

List factors that aid microbial colonisation

Answer 3

• Neutral pH
• Temperature (around 37⁰C)
• Nutrients (glucose, fats, protein)
• Oxygen, water

Question 4

List factors that hinder microbial colonisation

Answer 4

• Blood cells:
  
  • Lymphocytes (T-cells, B-cells, NK-cells)
  • Monocytes (macrophages)
  • Leukocytes (neutrophils, eosinophils, basophils)
  • Antibodies
• Rapidly moving blood
• Blood recirculation through spleen and liver-sinusoids which are lined with phagocytes

Question 5

What are some examples of Microbial infection of the blood

Answer 5

Bacteria - S.aureus, Brucella, Gram+ and Gram- spp (TSS - toxic shock syndrome)
Viruses - HIV, Ebola, Dengue fever
Protozoa - Plasmodium (malaria), Toxoplasma
Fungi – yeasts
Helminths – roundworms, blood flukes

Question 6

What is immunity?

Answer 6

Immunity (or resistance) is the ability to ward off damage or disease through body defences

Question 7

What are 2 types of immunity?

Answer 7

Nonspecific (innate), Specific (adaptive)

Question 8

What is Nonspecific (innate) immunity

Answer 8

• Defences present at birth
• Acts against all microbes in the same way
• Includes physical and chemical barriers eg. intact skin, stomach acids, mucus, fever, inflammation, phagocytes
• Designed to prevent microbes entering body and helps eliminate those that do gain access

Question 9

What is Specific (adaptive) immunity

Answer 9

• Defences that involve specific recognition of microbe

- Involves T- and B-lymphocytes

Question 10

The immune system consists of cells and molecules that bring about the immune _______

Answer 10

response

Question 11

What is active immunity

Answer 11

• When B-lymphocytes encounter antigens they produce antibodies against them
• Is acquired in one of two ways:
• From exposure to the disease OR
• From vaccine

Question 12

What is passive immunity

Answer 12

• Ready–made antibodies are introduced into the body
• Is acquired in one of two ways
• From the mother (across placenta or in breast milk) OR
• From injection of preformed, exogenous antibodies (Igs-immunoglobulins)