Unit 3 Lecture 16 Flashcards
What are the functions of the lymphatic system?
- Drain excess interstitial fluid
- Transport dietary lipids
- Carry out immune responses
What are the primary lymphatic organs?
- Red bone marrow
2. Thymus
What are the secondary lymphatic organs and tissues?
- Lymph nodes
- Spleen
- Lymphatic nodules/ follicles
What do lymphatic vessels do to excess interstitial fluid?
drains excess interstitial fluid and returns it to the blood stream
Where are lymph capillaries found
Adjacent to blood capillaries
Describe characteristics of lymph capillaries
- larger than blood capillaries
- “one way” valves
Name the pathway of the lymphatic system
Lymphatic capillaries -> lymph node -> lymphatic duct (left and right) -> lymphatic vessel -> valve -> lymph node -> lymphatic capillary
How many lymphatic ducts are in the body?
2
Thoracic (left) and right lymphatic duct
What are the body’s innate defenses? (Line of defense)
- physical barriers
- fevers
- inflammation
- cells and chemicals
What do the “lines of defense” fight?
invasion by pathogens (bacteria, viruses etc)
What is the first line of defense?
Physical barriers
What are types of physical barriers?
- Skin
- Mucus membranes
- hairs and cilia
- acid
- tears
How does skin fight pathogenic invasions?
- Sebaceous glands
- sudoriferous glands (sweat glands)
- lysozyme
What in mucus membranes fights pathogenic invasions?
- mucus is secreted by specialized epithelial cells called goblet cells
What on hairs and cilia fight pathogens?
- mucus coated hairs
- cilia on specialized epithelial cells that line the trachea
What is the pH of stomach acid?
2.0
What is found in tears?
lysozyme
What do invading microorganisms cause in relation to fevers?
Abnormally high body temperature
What is pyrogen?
a chemical secreted by leukocytes and macrophages that deals with fevers
What does pyrogen trigger in the body?
It resets the body’s thermostat upward
What does high fevers do to enzymes?
High fevers are dangerous because is causes denature enzymes
How are moderate fevers beneficial?
- it causes liver and spleen to sequester iron and zinc…. bad levels of this can cause bacteria
- increases metabolic rate -> repairs tissues faster
- triggers production of interferons
What are the functions of the inflammatory response?
- prevents the spread of damaging agents to nearby tissues
- disposes of cell debris and pathogens
- sets the stage for repair processes
What 4 signs show acute inflammation?
- redness
- heat
- swelling
- pain
What type of cells are vital in fighting infections?
White blood cells
What type of white blood cells is the most abundant in the body?
Neutrophils
What are the overall functions of white blood cells?
- attacks microorganism directly
- hindering their ability of microorganism to move, grow and reproduce
What is the importance of the neutrophil?
fastest responder to bacteria
What are the function of neutrophils
DESTROY BACTERIA by releasing lysozomes and strong oxidants (H2O2)
What is the importance of basophils?
Exit capillaries at sites of inflammation and play a role in allergic reactions
What is the function of basophils?
- releases hormones to raise inflammatory response
- contribute to allergic reactions
What is the importance of eosinophils?
- Responds to and attacks parasites
- enters ISF and releases histamines
- phagocytizes antibody-antigen complexes
What happens when eosinophils enters ISF and releases histamines?
slows down inflammation caused by basophils
Describe the main types of lymphocytes
- most types involved in adaptive immunity
- natural killer (NK) cells are involved in innate immunity (line of defense)
What type of lymphocytes (cells) are involved in adaptive immunity?
- B lymphocytes (B cells)
- T lymphocytes (T cells)
What are the functions of natural killer (NK) cells?
- kill virus infected cells
- kill tumor cells
What is the importance of monocytes?
arrive late to infections but in BIG numbers
What is the functions of monocytes?
- destroy microbes and clean up dead tissue after infection
- wandering macrophages in ISF
What are natural killer cells?
specialized class of t-lymphocytes which perform innate functions
What is the name of the process that NK cells “kill”
cytolysis
How does cytolysis work?
NK cells secretes a chemical known as perforin which punches holes in the cell membrane
What does low NK cell count mean?
HIV/AIDS
What proteins are responsible for the destruction of cells?
Antimicrobial proteins
What is the importance of antimicrobial proteins?
enhance the innate defenses (line of defense)
What are the specific functions of antimicrobial / antiviral proteins?
- attack microorganisms directly
- hinder the ability of some microorganism to reproduce
What are the two most important types of antimicrobial proteins?
- Interferons
2. Complement proteins
Where are interferons produced?
- Virus infected body cells
- T-lymphocytes
- natural killer cells
- macrophages
What are interferons?
a substance released by immune cells that alter the activity of other cells
What do interferons trigger on the cell they stimulate?
Triggers stimulation of anti-viral proteins by the non-infected cell
What is the purpose of complement proteins?
“complement” or enhance the action of antibodies
*attach to antigen-antibody complexes
What do complement proteins do to antigen-antibody complexes?
- attaches to their membrane
- forms a Membrane Attack Complex (MAC) which punches holes in bacterial cell membranes
What is the end result of MAC?
phagocytosis and inflammation
