week 1 Flashcards
What is the function of the immune system?
detect and eliminate pathogens
What are the 3 functions of the lymphatic system?
1) collect excess tissue fluid from cells and return to CV system to maintain fluid balance
2) facilitate immune response by producing + maturing lymphocytes
3) removes cellular waste products + debris from tissues
What is the function of the spleen
filters blood. detects blood borne pathogens
What are lymphatic vessels?
vessels that carry lymph
Contain one way valves
What is lymphatic fluid?
The clear liquid akin to plasma. It carries wastes, filters debris to and from the cardiovascular system.
Function of Lymph Nodes
Filter lymph fluid by destroying + removing pathogens and returning it to the CV system
houses B and T cells
What is the function of the thymus?
maturation of T cells
What is the function of tonsils + adenoids
Destroy inhaled pathogens.
What allows for bulk movement in lymphatic capillaries?
Flap-like openings, and anchoring filaments
What is the order of Lymphatic Vessels to Heart
Lymphatic Vessels, Lymphatic Trunk, Lymphatic Ducts, Thoracic Ducts, Heart
What is lymphatic tissue made out of?
Loose reticular connective tissue
What is diffuse lymphatic tissue made out of
a few scattered reticular tissue elements
What is found in the germinal centre of lymphatic follicles
Immature B cells
What happens in the hassals corspuscle of the thymus?
Destruction and development of T cells
Why are there more afferent than efferent vessels in the lymph nodes
So that there is enough time for the lymph nodes to carry out their functions.
What is the structure of the spleen?
White pulp, contains masses of lymphocytes.
Red pulp, made of blood filled cavities and splenic cords.
Whaat are the 4 types of tonsils?
Palatine, Pharyngeal, Lingual, Tubal
What is external mechanisms of innate immunity.
barriers, non-specific, immediate
What are internal mechanisms of innate immunity
Inflammation, fever, phagocytosis
What does innate immunity consist of
external and internal mechanisms.
What are the 2 components of adaptive immunity
humoral and cell mediated
What is cell mediated adaptive immunity
t cells
Lymphocytes are
B and T cells
Macrophages are
phagocytes for large molecules
Function of Eosinophils
Destroy parasites and assist in allergic reactions
Basophils are
Release histamine to initiate and allergic response and inflammation
functions of the compliment system
Opsonizes pathogens marking them for phagocytosis
assembles membrane attack complex –> cell lysis
Describe the classical pathway of complement activation
C1 binds to antibodies on microbes and recruits C2 and C4.
This leads to C3 being recruited and activated.
Activation of C3 results in C3a and C3b
Describe the alternative pathway of compliment activation
C3 and factors B, D, and P interact with the surface of microorganisms which stimulates C3a and C3b.
What is the function of C3b
Opsonization - coating pathogens to enhance phagocytosis.
What is the function of C3a
enhances inflammation
What is membrane attack complex
C5b-C9 insert into the microbial membrane forming a pore which drains water causing it to lyse.
What produces interferons
infected cells
What do interferons do once they are produced.
they diffuse to other cells and stimulate proteins that interfere with viral replication.
What is the benefit of a fever
raises our body temp so bacteria cannot survive
What does the spleen do during a fever?
sequester nutrients that the bacteria needs
What signals the brain to raise body temp
pyrogens secreted by lymphocytes.
What is the bodys normal body temp
37 degrees
What are the 5 signs of inflammation?
heat, redness, pain, swelling, loss of function
What causes pain during acute inflammation
pressure from swelling on nerves and mediators
what causes heat and redness
vasodilation
What is the cellular activity of acute inflammation
exudation of fluids and plasma
What is the cellular activity of chronic inflammation
proliferation of blood vessels and tissue necrosis
What is hyperemia
congested blood during inflammation
What are the 4 types of exudate
serous, fibrinous, haemoorrhagic, supperative
what is serous exudate
watery blisters
what is fibrinous exudate
sun burns, thick, high cell content
what is haemorrhagic exudate
severe immediate damage
what is suppurative exudate
purulent (pus)
Function of lymph nodes
Filter lymph by destroying. And removing foreign particles as it is returning to CV system
Thoracic duct
Receives lymph form lower body + left side of head and neck
Drain lymph back into bloodstream by emptying into the subclavian vein
Right lymphatic duct
Collects lymph from right upper body
Drain lymph back into bloodstream by emptying into the subclavian vein
5 steps of phagocytosis
- Recruited to site of infection by chemotaxis and activated by cytokines
- Phagocytes adhere to the surface of the pathogen using their surface receptors
- The phagocyte extends its cell membrane around the pathogen or particle, forming a pocket called a phagosome
- The phagosome fuses with the lysosomes becoming phagolysosome which contains enzymes that break down the pathogen
- The breakdown products of the pathogen are used for antigen presentation to activate the adaptive immune response
Are there special phagocytic cells in the oral cavity?
Yes - specialised oral mucosal macrophages
What are the 3 types of barriers?
- Physical
- Chemical
- Microbiota
examples of physical barriers
- intact skin
- hair in nose + ears
- ear wax
examples of chemical barriers
- sweat secrete salt + fatty acids which are bacterial inhibitors
- saliva and teras secrete lysosomes which are enzymes that breakdown bacterial cell wall
- lungs secrete mucus from goblet cells that traps pathogens. removes via cillia that pass the mucus up and out of the lungs and nose
- HCL in stomach
example of microbiota barrier
microbes that live in a symbiotic relationship with humans out compete pathogenic bacteria preventing them from establishing colonies in the human body
characteristics of innate immunity
- has no memory of previous infections
- reaction same for all pathogens
- response is immediate
give 3 examples of phagocytes
Neutrophil
Macrophage
Dendritic cell
2 roles of phagocytes
- Antigen presting cells (macrophage + dentritic)
- moves from site of infection to the lymph node to present non self antigen of engulfed pathogen on its MHCII marker to initiate the adaptive response - recognise, engulf and digest foreign materials via phagocyotis
What pathogens does the humoral response target? Which cells are involved?
Extracellular pathogens
B lymphocytes
What are compliment proteins
proteins that attack membranes in bacteria and form membrane attack complexes
Describe inflammation
- Damaged cells/tissues release cytokines.
- Mast cells are activated. This means that they release histamine.
- Histamine causes an increase membrane permeability. This means that more tissue fluid leaks out causing swelling and pain.
- Histamine also causes vasodilation. This means that there is more blood flow to the area to bring more immune cells and cause redness and an increase in temperature.
Lymph leaves a lymph node via _____________
Efferent lymphatic vessels
Primary lymphoid tissue
Bone marrow
Thymus
site of lymphocyte formation and maturation
–
Secondary lymphoid tissue
Lymph nodes
Spleen
Tonsils
Peyer’s patches
sites where lymphocytes interact with and filter extracellular fluids
Plasma
fluid in blood
to transport nutrients and waste around the body via blood
Tissue fluid
Found surrounding tissues (leaked out of cardiovascular system due to increased pressure )
to supply cells with a stable environment
bone marrow
primary lymphoid tissue
produce B & T lymphocytes,
mature B lymphocytes
