Lecture 36 - Immune System Overview Flashcards
What is the immune system?
It’s a diffuse collection of cells and organs that are responsible for the ability to resist infection and disease
Name 3 examples that the immune system protect the body against?
- Pathogens
- Toxic material
- Own misfunctioning cells
Function of physical barriers against infection
Anatomical and physiological mechanisms prevent entry of foreign organisms and substances
Function of cell-mediated immune responses
Innate and adaptive defence responses that rely on WBC activity
What are physical barriers made of?
Structural features - work to prevent a pathogen from entering the body (ex. skin and hair)
Chemical secretions - used to neutralize and destroy pathogens (ex. lysozyme, stomach acid)
These defences are created by non-immune cells
What is the most important physical barrier of the body? Why?
The integument. It has:
- Secretions - washes away/destroys potential pathogens
- Hair - keeps away potential hazards away from the skin surface
- Stratified squamous epithelium - many closely interlocked layers which keep intruders out
What is the purpose of mucous membranes?
It lines the digestive, respiratory, urinary, and reproductive tracts and provide protection against foreign substances and pathogens
What are immune system responses mediated by?
WBCs - both innate and adaptive immune responses rely on the activation and signalling of specialized immune cells
Where do WBCs come from and how are different WBCs divided?
They all come from red bone marrow
WBCs are divided based on:
- Function
- Anatomy
- Developmental history
What are the 3 functions of immune responses that are mediated by WBCs?
- Detection/recognition of invaders or abnormality
- Secretion of chemicals that alter the local environment or signal to other cells
- Destruction of foreign particles, pathogens, and diseased cells
No one type of WBCs performs all of these functions, but some are involved in more than one
What are the 2 types of immune responses
Innate responses - nonspecific responses that react to any threat they detect. They are present from birth
Adaptive responses - specific and powerful responses triggered by exposure to particular antigens. They must be “learned” over the lifetime
What does the lymphatic system consist of?
It consist of vessels that move lymph through the body, and tissues that produce or house lymphocytes
What is lymph?
It’s a connective tissue that resembles blood, but lacks most of the cells and plasma proteins
T/F? The lymphatic system is synonymous with the immune system
False - it is not synonymous with the immune function
What are the 2 main non-immune functions of the lymphatic system?
- Return of filtered fluid from ISF to plasma
- Transport of digested and absorbed lipids