W4: Immune System Flashcards
We measure the immune system the same way we measure cortisol
Through saliva and blood
What is the immune system?
Consists of cells, tissues and molecules that facilitate resistance to infections (keep you healthy)
What is immunity?
Resistance of pathogens and their toxic effects
What is the immune response?
A coordinated response to foreign substances in the body
What is a pathogen?
A pathogen is usually defined as a microorganism that causes, or can cause, disease.
A pathogen can be cellular (living) such as.. (4) and what they cause..?
- Parasities –> Tapeworm
- Protozoa —> Malaria
- Fungi —> Athlete’s foot
- Prokaryote (i.e bacteria) –> Leprosy
A pathogen can also be acellular (non-living) - (2)
- Virus – > AIDS
- Prion –> CJD
Role of the immune system is to provide defense against
- pathogens and foreign substances
Role of the immune system is responsible to maintain homeostasis
Even when you are not ill/immune system is working normal
Homestasis will…. (2)
- Protection against the growth of tumour cells
- Destruction of abnormal or dead cells
Immune system is a functional system and NOT a (2)
NOT an organ system - no specific location immune system is located
It is everywhere
The innate immune system has two functions (2)|
- External defences
- Internal defences
External defences of the immune system are
Skin
- Skin allows to resist infections and providing a passive physical barrier against infection
External defences of the immune system
Flushing action (3)
- Flushing action of urine, saliva and tears serves to carry microbes away from the body
- The flushing action of urine is responsible for the normally sterile environment of the urinary tract.
- When microbes/debris that are in the eye are flushed out by the tears in the eyes
Internal defences of the immune system is in the
Blood
What is composed in the blood? (3)
- Red blood cells - move oxygenated blood
- Plasma contains proteins (build muscle, restore energy, create enzymes, hormones) and cytokines (NT used in immune sys to communicate to other cells)
- White blood cells
What are the different types of white blood cells? (3)
- Neutrophils
- Macrophages
- Lymphocytes
Neutrophils (3)
- Most abundant WBC (~50-60%) in the blood
- Not stationary and move
- Efficient phagocytes
What is a phagocyte?
Cell which absorbs bacteria and other small cells and particles
Example of Neutrophils (2)
- They float around bloodstream
- See something that shouldn’t be there and they engulf it/break it down
Macrophages (3)
- Largest stationery cells tissues
- Found mostly at likely sites of infections
- Digests cellular debris, foreign substances, cancer cells and anything else that is not specific to healthy body
Macrophages placed at sites of infections such as (2)
- Stomach and intestine
- Lungs
Example of macrophages (3)
- Like a bodyguard
- Anything we inhale in the lungs has to go through macrophages first
- If let pass macrophages (may be too small) then neutrophils break it down
Lymphocytes (4)
- It is a type of white blood cell
- There are T-lymphocytes
- B - Lymphocytes, plasma cells
- Natural Killer cells
Function of lymphocytes (2)
- Kill virus/bacteria-infected cells
- Kills cancer cells
Lymphocytes are used when… (3)
- Neutrophils float around and collect anything foreign substances
- Macrophages stop this from happening in the first place (above) being a bodyguard in bloodstream, lungs and stomach
- If these defences are not effective and infect cells , kill cell -lymphocyte
Lymphocytes are identifiable by
large nucleus
Natural killer cells
when its a health/uninfected cell
- Natural killer cell (NK) recognises receptors on a healthy cell and does not kill it
Natural killer cells
when its a infected cells that does not present receptors
- NK cells release enzymes and kill cell and kill both host cells and pathogens
One of the receptors that NK cells checks on a cell is
Toll-like receptors (TLRs)
TLRs are
- Proteins on membranes of cells
TLRs are found on the outside of (3)
- Macrophages
- Neurons (dendrites)
- Skin (epithelial) cells
TLRs look out for (2)
Pathogens
If a pathogen attaches to one of the receptors on outside of cell, alert rest of body to have an immune response
If TLRs find one of the pathogens (attached to one of the receptors) - (3)
Trigger events to kill or protect against it
They are immune sensors
They release cytokines (NT for the immune system)
Diagram of TLRs example - look out for non-healthy pathogens
Cytokines (2)
- Small proteins secreted by cells of the immune system
- Affect the behaviour of other cells by releasing molecules
Three types of cytokines (3)
- Interferons
- Interleukins
- Tumour necrosis factor (TNF) - release stuff to kill tumour cells
Inferons (3)
- Proteins produced and released by virus-infected cells
- Secrete proteins interfere with virus replication
- Warn neighboring cell that a virus is around
Interferons diagram (3)
- Warn neighbouring uninfected cells that a virus is around to destroy RNA and reduce protein synthesis
- Signals neighbouring infected cells to undergo apoptosis (programmed cell death)
- OR it will activate the immune response within the cell itself
Interleukins
Several interleukins are released if the cell is detected of being attacked/infected by pathogens
How many interleukins?
1-37
Interleukins are (2)
- Not stored inside cells
- Quickly synthesised and secreted in response to infection
Interleukins are responsible with the immune system to do.. (4)
- growth) of immune cells
- Increase antibody production
- Activation of immune cells
- Deal with Inflammation
When a cell detects potential virus/bacteria
Interleukin 6 can be
activated
Interleukin 6 primarily responsible for/plays a role in both
Immune responses
Inflammation
What 2 things interleukin 6 do?
- Raises body temperature (fever) to kill viruses and bacteria
- Stimulates HPA axis (cortisol release)
Why does interleukin 6 stimulate the HPA axis (cortisol release)? - (2)
- If there is large amounts of interleukin 6
- Body releases cortisol, which suppresses the immune system, to lower the levels of interleukin 6 to maintain homeostasis - keep the balance
What happens in inflammation? (6)
- Blood vessels in tissue dilate (widen) to allow more blood to reach the infected or injured area
- Inflamed areas look red and feel hot due to increased blood
- Increased blood flow allows immune cells to reach the infected area
- This allows immune cells to pass through blood vessels to enter the tissue
- Excess fluid in inflamed areas cause swelling
- Inflammation accelerates healing process
Diagram of inflammation (2)
- Remove spliter the skin swells up
- Interleukin responsible: Skin becomes red - blood is pooling there in the skin and tissues so WBC can fight any foreign substances from cut
Inflammation (adapative)
Adaptive short-term
Long-term or repeated inflammation (constantly hurting/stress) can lead to:
- Cardiovascular disease
- Cancer (damages DNA)
How can long-term inflammation lead to cardiovascular disease?
- High inflammation body releases cortisol again to balance interkeuns 6 which can increase BP and heart workers harder.
How can long-term inflammation lead to cancer? (3)
- When you are inflamed for prolonged periods
- immune system is not able to effectively check if there is no cancerous cells or no abnormal cells
- Since cortisol release (by HPA axis) suppresses the immune system
Interleukin 6 is mediated by
(Chronic , long-term/repeated) inflammation
Sympathetic Nervous Activity
Stress typically (2)
Suppresses immune functioning - Usually temporary
Allocate resources away from the immune system to overcome the stressor
Long-term response to stress triggers HPA axis (4)
- Relseases Cortisol
- Cortisol directly inhibits/suppresses the functioning of the immune system
- This reduces the release of cytokines (interleukin 6)
- reduces the production of immune cells and checking for cancerous cells
In chronic stress (continously experience stress)
Immune sys eventually resists suppression of cortisol
Which means.. - (3)
- Still get heightened cortisol release but now it is not suppressing the release of interleukin 6, WBC and other cytokines
- Two sys working in conjunction that should not be working together - cortisol release (heart working faster) and part of parasympathetic system (immune system)
- Dysregulation of the immune system and HPA axis - both not working at optimal capacity
Chronic stress - dysregulation of immune sys and HPA axis has compounded effects on the body such as..(3)
Higher rates of inflammation from interleukin 6
Oxidative stress on molecules
Hypertension from HPA axis
