Compendium 11 - How do we protect ourselves Flashcards
differentiate between the immune system and the lymphatic system
the immune system (active) - contains the proteins, cells, tissue, organs to fight a pathogen
the lymphatic system is the stansport system for the cells of the immune system
define a pathogen
a foreign agent presenting non-self antigens
can be parasites, bacteria, fungi, protozoa
what does the immune system fight against
- foreign substances and internal threats (own cells presenting antigens wrong eg. cancer cells)
what are the components of innate immunity
first line of defence = physical barriers
second line of defence =
- white blood cells (phagocytes)
- inflammation
- chemical mediators
- fever
what are the two types of of adaptive immunity (and what cells do they involve)
- cell mediated immunity (T cells)
- antibody mediated immunity (B cells)
what are 3 characteristics of innate immunity
- non specific
- present at birth
- no memory
what are some examples of physical barriers (in innate immunity) (7)
- skin
- mucous membranes
- saliva
- tears
- acid
- urine flushes
- cillia
What are 4 chemical mediators of the innate/nonspecific immune response and what do they do
histamine - vasodilation, increase vascular permeability, attract WBCs
cytokines - activate t cells, initiate phagocytosis and inflammations,
secreted by cells to stimulate neighbour cells, regulate duration and intensity of response
complements- stimulate lysis
interferons - antiviral (restricts replication and alerts adaptive immunity branch)
what are the 5 types of WBCs and what is the role of each
neutrophils - often the first responder, phagocytosis, acute inflammation
macrophages - phagocytosis, repair, activate B and T cells
Basophils - produce histamine, immunosurveillance
Eosinophils - respond to parasitic infection and allergy
Natural killer - lysis of viral infected cells and cancer cells
what is inflammation and why are the symptoms caused
- it is the localised response to tissue damage (pathogens or injury)
redness + heat (due to increased blood flow)
swelling (increased permeability = more fluid leaves capillaries)
pain ( increased fluid pressure stimulates nerve endings)
what is fever and what is the effect of rising temperature on the body
- generalised response to damage/infection
increased temp results in:
- an increase in antimicrobial substance / augmented performance of immune cells
- decrease microbial growth
- speed up body reactions to help tissue repair
what is the role of MHC class 1
it is a pathway that puts peptide fragments from inside a cell on the surface as antigens, so other cells can recognise if its a normal cell or not
- eg. if infected with a virus, viral proteins will be put out as antigens and alert other cells that it is infected
what is the process of cell mediated immunity
- T cell receptors recognise specific viral protein
- Cytotoxic T cell divides into 2 daughter cells ( if helper t cell helps, via interleukin-2)
- daughter t cells can now kill any cell with that antigen
what is the process of antibody mediated immunity
- WBC phagocytosis of antigen + express the antigen on their surface
- helper t cell binds to it + secretes interleukin (if it recognises/confirms it is a bad antigen)
- interleukins stimulate B cells to devine and produce antibodies
what are the 2 types of B cells
plasma B cells - make antibodies
memory cells
what are the 3 effects of antibodies
- inactivate antigen by binding to it
- bind antigens together
- facilitate phagocytosis (bigger complex - easier to get)
what do memory cells do during a secondary response
- divide rapidly to form more plasma cells and memory cells (causing a faster and greater response)
how long is a first response and secondary response to an antigen
first response - 3 to 14 days
second response - hours to a few days
what are 3 functions of the lymphatic system and how do they work
- fluid balance : excess interstitial fluid enters lymph capillaries and becomes lymph then returns to cardiovascular system
- fat absorption : from digestive tract via lacteals
- defence : filters lymph and blood (lymph filters through lymph nodes and blood filters through spleen)
what is lymph
made up of water and solutes
solutes come from :
plasma - ions, nutrients, gases, proteins
cells - hormones, enzymes, waste products
what are 3 characteristics of lymphatic vessels
- more permeable
- one way flow (away from tissues)
- found everywhere except in the CNS, bone, avascular tissue
how is one way flow in the lymphatic system maintained
- epithelial cells that form the inner lining of capillaries form valve like structures
what are the layers of lymph vessels
- endothelium, smooth muscle, connective tissue
what is the order of structures that lymph flows through
- capillaries > vessels > trunks > ducts
how does lymph move around the body
contraction of surrounding skeletal muscles
where does lymph enter back into the cardiovascular system
the veins
where do you find lymph nodes and what is their function
they are distributed along lymph vessels and help to filter lymph
what give lymph vessels a beaded appearance
the valves
what are the names of the 5 lymph trunks and where do they merge
- jugular
- subclavian
- bronchomediastinal
- intestinal
- lumbar
the trunks can either connect to large veins or merge again to form ducts
what are the 2 lymphatic ducts and where do they drain
- right lymphatic duct : drains right side of head, right upper limb and right thorax
- thoracic duct : drains the rest of the body
what are lymphatic organs made up of
the are made of lymphatic tissue
which consists of :
- lymphocytes
- macrophages
- dendritic cells
- connective tissue
in a fine network of reticular fibres (made by connective reticular cells)
What are the lymphocytes found in lymph organs and where are they from
- b and t cells derived from the bone marrow in a process called hematopoiesis
what is the role of reticular fibres in lymphatic organs
- a fine network to trap microorganisms and other particles
what lymphatic tissues are encapsulated and which are not
encapsulates in CT : lymph nodes, spleen, thymus
not encapsulated : mucosa-associated lymphoid tissue (found beneath epithelium)
what are the 2 types of lymphatic tissue. Describe them
- diffuse : dispersed lymphocytes and macrophages that blends in with surrounding tissue
- nodules : denser aggregations. found in loose connective tissue of digestive, respiratory, urinary and reproductive systems. (called the peyer’s patch in small intestines)
what are the 2 functions of the lymph nodes
the PRIMARY FUNCTION is to filter lymph, substances are trapped and can be removed by phagocytosis by macrophages.
another function is to help to activate the immune system, lymphocytes in lymph nodes monitor lymph for antigens and cause an immune response if identify an antigen.
how are lymph nodes organised / structured
- they have an afferent (in) and efferent (out) vessel
and the lymph node itself has a cortex and medulla (more diffuse) which is surrounded by a dense CT capsule
what is the structure and function of the tonsils, and what are the 3 types
- they are a large group of lymphoid tissue in the nasopharynx and oral cavity
- they provide protection against bacteria and harmful material
3 types are : - palatine
- pharyngeal
- lingual
What are the 4 roles of the spleen
- monitors and filters blood + detects and responds to foreign agents
- destroys defective RBCs
- regulates blood volume
- has a limited reserve of RBCs
what is the spleen made up of
75% red pulp associated with veins - a fibrous network of macrophages and RBCs
25% white pulp associated with arteries - lymphatic tissue
what where is the thymus located
superior mediastinum
describe the structure of the thymus
- it is surrounded by a connective tissue capsule that divides it into lobules
- each lobule has a cortex (numerous lymphocytes) and medulla (fewer lymphocytes)
at what age is the thymus full size
1 yr olds
what is the function of the thymus
maturation of T cells ( come from bone marrow and proliferate and mature in the thymus)
what is chyle
liquid that drains from lacteal into lymphatic system
(lymph with lots of fatty acids that has come from the intestines)
