L1 Flashcards
What is the immune system composed of?
organs
cells
molecules
What is an immune system?
Organised system of organs, cells and molecules to defend body against diseases
What is a pathogen?
Disease causing pathogens
Smallest to largest, microbes
Viruses, bacteria, fungi, protozoa
What are the primary lymphoid organs?
Thymus, Bone marrow
What is the purpose of primary lymphoid organs
-Production of white blood cells (lympocytes)
What is the purpose of secondary lymphoid organs
Sites where immune responses are initiated
What is the function of bone marrow
-Source of stem cells into innate and adaptive arms
What is the function of thymus
‘School’ for white blood cells called T cells
Developing T cells learn to not react to self
what are the secondary lymphoid organs?
Spleen and lymph nodes
What is the function of the spleen
Initiation for immune responses against blood borne pathogens (filter blood)
Where are lymph nodes located?
Along lymphatic vessels
Purpose of lymphatic vessels
Transports lymph fluids from tissues and filter it to re circulate into blood
Purpose of lymph nodes?
Site of initiation of immune responses for pathogens in the tissue
What are the layers of defense of the immune system, outer to inner?
Chemical and physical barriers
Innate arm
Adaptive arm
What is the epidermis and its function
Dead cells, phagocytic immune cells which
Epidermis is shedded
What is the dermis layer?
Thick layer of connective tissue, collagen and phagocytic immune cells
What are defensins and what to do they do?
Antimicrobial peptides which form pores in microbes membranes, killing them
Function of lysozyme?
Breaks down bacterial cell walls
What are the two chemical defences which directly affect the skin environment
Sebum: low pH
Salt: Hypertonic
Features of mucous membranes
1-2 layers
Epithelium: tightly packed live cells, constantly renewing, mucus producing
How does mucous membrane defend against microbes and what kind of defence is it?
Physical defence
-Mucus traps microbes
-tightly packed, unable to get through
What is the mucociliary escalator?
Cilia moves mucus (trapped with microbes and dust) up to pharynx
What are the chemical defences of mucosal surface: stomach, Gall bladder, Intestine
Low pH
Bile
Digestive enzymes
What signals can the innate arm send to adaptive arm?
Signals to prepare for defence against microbes
Features of innate arm immunity
-Already in place
-rapid
-non specified
-No specific memory
Features of adaptive arm
-improves during response
-slow
-variable
-highly specific
-Has memory
