Infectious Diseases and Immunology

What term describes the physical & chemical barriers and cellular defences e.g. skin, mucus, tears, digestive enzymes?

Innate (general) immune system

What term describes active & passive immunity?

Adaptive (specialised) immune system

Do the eyes have a low innate immunity? Why/why not?

Yes as the inflammatory immune response is limited to prevent vision impairment

What is present in both the innate & adaptive immune system?

White blood cells

What term describes the body’s rapid, non-specific defence against pathogens?

Immediate response

What term describes the quicker response due to memory cells?

Learned response

Which cell causes inflammation by releasing chemicals e.g. histamine & recruits other cells to the location?

Mast

Which cell carries out phagocytosis & recruits other cells to the location?

Neutrophil

Which cell carries out phagocytosis & digests pathogens, dead cells, and debris?

Macrophage

Which cell identifies cells that have been infected by pathogens i.e. infected host cells, & tumour cells and destroy them?

Natural killer (NK)

Which cell moves from the site of infection to the lymphoid system & activates the adaptive immune system (what vaccinations mainly rely on)?

Dendritic

Which cell activates the adaptive immune system by travelling to the site of infection & interacting with the innate immune system?

T-helper lymphocyte (CD4+)

Which cell is similar to NK cells but require activation?

Cytotoxic T-lymphocyte (CD8+)

Which cell remembers the interaction made by CD4+ cells when the same infection returns and matures into cytotoxic cells?

T-memory lymphocyte

Why do we need booster vaccines?

Because T-memory cells tend to forget the interaction made by CD4+ cells

Which cell interacts with CD4+ cells and matures into plasma cells which quickly produce specific antibodies to particular antigens, and memory cells?

B cells

What term describes any pathogenic microorganism/entity that can invade a host & trigger an immune response, potentially leading to disease?

Infectious agent

What do infectious agents possess in order to be recognised by the host’s immune system?

Antigens

What gives a positive result in a Gram stain test (retains crystal violet dye & remains purple) as it has a thick peptidoglycan cell we all & no outer membrane?

Gram-positive bacteria

What gives a negative result in a Gram stain test (appears red/pink) as it has a thinner peptidoglycan cell wall and an outer membrane?

Gram-negative bacteria

What term describes an acellular nucleic material that contain either DNA or RNA surrounded by a protein coat (capsid)?

Virus

Why are viruses considered non-living?

Requires a host to reproduce

Which viruses are most common?

Polyhedral & spherical

What term describes no-phototropic eukaryotic microorganisms with a rigid cell wall?

Fungi

Some fungi are?

Symbiotic

What are fungal infections caused by?

Yeast or mould

When do fungal infections occur?

When immunocompromised

Where are fungal infections most commonly found?

In the nails or the skin

What is ‘furry tongue’ caused by?

Smoking

What term describes eukaryotic, unicellular, motile microbes?

Protozoa

How are protozoa classified?

By their means of locomotion (movement or the ability to move from one place to another)

What type of disease do protozoa cause a lot of?

Water-borne

What term describes dynamic relationships where the host & pathogens influence each other’s survival, often leading to disease?

Host-pathogen interactions

What do host-pathogen interactions involve?

Complex molecular, cellular, immunological responses from the host’s immune system to combat invading microbes

Why are immunosuppressants sometimes given?

Due to overactivity of the immunological response which may damage host cells e.g. myelin sheath of nerve cells

What term describes a set of six intertwined links that allow for communicable diseases to spread?

Chain of infection

What does the chain of infection include?

• Infectious agent

• Reservoir

• Port of exit

• Mode of transmission

• Portal of entry

• Susceptible host

What term describes a microorganism that can cause disease/infection?

Infectious agent

What term describes where microorganisms live without causing infection to humans e.g. cholera in water, Covid-19 in bats?

Reservoir

What term describes how microorganisms leave the reservoir e.g. sneezing in influenza?

Port of exit

What term describes the action that causes microorganisms to enter the body e.g. hands touching the eyes after touching a surface infected by influenza?

Mode of transmission

What term describes the opening where the pathogen may enter e.g. nose, eyes, mouth, wounds?

Portal of entry

What term describes someone at risk of infection?

Susceptible host

What will happen if the chain of infection is broken at any time?

Infection will not occur

The earlier the chain of infection is broken…?

The less risk & more cost-effective