1. Concept of Immunity:
Immunity: ability to ward off damage or disease through our defenses.
Lack of resistance or vulnerability= susceptibility.
Two types of immunity: innate and adaptive.
Innate immunity:
refers to defenses that are present at birth.
Acts on all microbes in the same way, does not have a specific
recognition system.
Components: first line of defense= physical and chemical barriers of
the skin and mucous membranes; second line of defense=
antimicrobial substances, natural killer cells, phagocytes, inflammation
and fever.
Early warning system- prevents microbes from entering and eliminates
those ones that do gain access.
Adaptive immunity:
Involves specific recognition of microbes once it has breached the
innate defenses.
Based on specific response to a specific microbe- adapts or adjusts to
handle a specific microbe.
involves= lymphocytes (type of WBC) called T-lymphocytes and B-
lymphocytes.
Overview of Lymphatic system:
,Components of lymphatic system:
Consists of a fluid called lymph- vessels are called lymphatic vessels
that transport lymph, lymphatic tissue and red bone marrow.
Assists in the circulation of body fluids and helps defend body against
disease causing agents.
Interstital fluid passing into lymphatic vessels is called lymph.
Intersitial fluid= located between cells; lymph= located inside
lymphatic vessels and lymphatic tissue.
Lymphatic tissue= specialized reticular connective tissue with large
numbers of lymphocytes.
Functions of the lymphatic system:
Three primary functions:
Drains excess interstital fluid: does this from tissue spaces and returns
the fluid to blood. Helps maintain circulating blood volume.
Transports dietary lipids: transports lipids and fat-soluble vitamins
(ADEK) absorbed by gastrointestinal tract.
Carries out immune responses: initiates highly specific respnses
directed against particular microbes or abnormal cells.
Lymphatic vessels and Lymph Circulation:
Lymphatic vessels begin at lymphatic capillaries.
They are located in spaces between the cells and are closed at one
end.
Lymphatic capillaries unite to make lymphatic vessels- resemble smal
veins in strucure but have thinner walls and more valves.
Lymphatic capillaries:
, Greater permeability than blood capillaries and can absorb larger
molecules like proteins and lipids.
Larger diameter than blood capillaries and have a unique structure that
allows one way flow of interstitial fluid.
Pressure greater in intersitital fluid than lymph= separation of
endothelial cells= opening of the one-way swinging door which lets
intersitial fluid into lymphatic capillary.
Pressure greater in lymphatic capillary= cells tightly packed to avoid
fluid leak.
Pressure is relieved as lymph moves further down the lymphatic
capillary.
Anchoring filaments= attached to lymphatic capillary= contain elastic
fibres.
Excess intersitital fluid accumulaiton= tissue swelling=anchoring
filaments pulled making openings even larger to allow more fluid
through the lymphatic capillaries.
Lacteals: specialized lymphatic capillaries= carry dietary lipids into
lymphatic vessels and ultimately into blood.
Chyle= creamy white appearance of lipids in the small intestine.
Uusally, lymph is either clear or pale-yellow.
Lymph Trunks and Ducts.
Lymph trunks: united lymphatic vessels in a particular region.
Major trunks: lumbar, intestinal, bronchomediastinal, subclavian, and
jugular trunks.
Lumbar trunk: Drain lymph from lower limbs, walls of viscera of pelvis,
kidneys, adrenal glands and abdominal wall.
Intestinal trunk: drains lymph from stomach, intestines, pancreas,
spleen and parts of liver.
, Bronchomediastinal trunk: drains lymph from thoracic wall, lungs,
heart.
Subclavian trunks: drains the upper limbs.
Jugular trunks: drain head and neck lymph
Passage of lymph trunks to venous system differs on right and left side
of the body.
Lymph from upper right quadrant= returns to superior vena cava from
right brachiocephalic vein.
Lymph from left upper side of body and entire body below diaphragm
returns to superior vena cava via the left brachiocephalic vein.
Formation and Flow of Lymph:
About 3 litres of excess filtered fluid becomes lymph- by being drained
into lymphatic vessels.
Returns lost plasma proteins and plamsa to the bloodstream.
One-way movement of lymph= ensured by presence of valves.
Sequence of fluid flow:
: blood capillaries(blood) → interstital spaces (interstitial fluid) → lymphatic
capillaries (lymph) → lymphatic vessels (lymph) → Lymphatic trunks or ducts
(lymph) → junction of the internal jugular and subclavian veins (blood).
Two pumps that aid the return of venous blood to the heart maintain the flow
of lymph:
1. Respiratory pump:
Flow of lymph- maintained by pressure changes during inhalation.
Pressure high- flows from abdominal region (high pressure) to thoracic
region (low pressure).
Immunity: ability to ward off damage or disease through our defenses.
Lack of resistance or vulnerability= susceptibility.
Two types of immunity: innate and adaptive.
Innate immunity:
refers to defenses that are present at birth.
Acts on all microbes in the same way, does not have a specific
recognition system.
Components: first line of defense= physical and chemical barriers of
the skin and mucous membranes; second line of defense=
antimicrobial substances, natural killer cells, phagocytes, inflammation
and fever.
Early warning system- prevents microbes from entering and eliminates
those ones that do gain access.
Adaptive immunity:
Involves specific recognition of microbes once it has breached the
innate defenses.
Based on specific response to a specific microbe- adapts or adjusts to
handle a specific microbe.
involves= lymphocytes (type of WBC) called T-lymphocytes and B-
lymphocytes.
Overview of Lymphatic system:
,Components of lymphatic system:
Consists of a fluid called lymph- vessels are called lymphatic vessels
that transport lymph, lymphatic tissue and red bone marrow.
Assists in the circulation of body fluids and helps defend body against
disease causing agents.
Interstital fluid passing into lymphatic vessels is called lymph.
Intersitial fluid= located between cells; lymph= located inside
lymphatic vessels and lymphatic tissue.
Lymphatic tissue= specialized reticular connective tissue with large
numbers of lymphocytes.
Functions of the lymphatic system:
Three primary functions:
Drains excess interstital fluid: does this from tissue spaces and returns
the fluid to blood. Helps maintain circulating blood volume.
Transports dietary lipids: transports lipids and fat-soluble vitamins
(ADEK) absorbed by gastrointestinal tract.
Carries out immune responses: initiates highly specific respnses
directed against particular microbes or abnormal cells.
Lymphatic vessels and Lymph Circulation:
Lymphatic vessels begin at lymphatic capillaries.
They are located in spaces between the cells and are closed at one
end.
Lymphatic capillaries unite to make lymphatic vessels- resemble smal
veins in strucure but have thinner walls and more valves.
Lymphatic capillaries:
, Greater permeability than blood capillaries and can absorb larger
molecules like proteins and lipids.
Larger diameter than blood capillaries and have a unique structure that
allows one way flow of interstitial fluid.
Pressure greater in intersitital fluid than lymph= separation of
endothelial cells= opening of the one-way swinging door which lets
intersitial fluid into lymphatic capillary.
Pressure greater in lymphatic capillary= cells tightly packed to avoid
fluid leak.
Pressure is relieved as lymph moves further down the lymphatic
capillary.
Anchoring filaments= attached to lymphatic capillary= contain elastic
fibres.
Excess intersitital fluid accumulaiton= tissue swelling=anchoring
filaments pulled making openings even larger to allow more fluid
through the lymphatic capillaries.
Lacteals: specialized lymphatic capillaries= carry dietary lipids into
lymphatic vessels and ultimately into blood.
Chyle= creamy white appearance of lipids in the small intestine.
Uusally, lymph is either clear or pale-yellow.
Lymph Trunks and Ducts.
Lymph trunks: united lymphatic vessels in a particular region.
Major trunks: lumbar, intestinal, bronchomediastinal, subclavian, and
jugular trunks.
Lumbar trunk: Drain lymph from lower limbs, walls of viscera of pelvis,
kidneys, adrenal glands and abdominal wall.
Intestinal trunk: drains lymph from stomach, intestines, pancreas,
spleen and parts of liver.
, Bronchomediastinal trunk: drains lymph from thoracic wall, lungs,
heart.
Subclavian trunks: drains the upper limbs.
Jugular trunks: drain head and neck lymph
Passage of lymph trunks to venous system differs on right and left side
of the body.
Lymph from upper right quadrant= returns to superior vena cava from
right brachiocephalic vein.
Lymph from left upper side of body and entire body below diaphragm
returns to superior vena cava via the left brachiocephalic vein.
Formation and Flow of Lymph:
About 3 litres of excess filtered fluid becomes lymph- by being drained
into lymphatic vessels.
Returns lost plasma proteins and plamsa to the bloodstream.
One-way movement of lymph= ensured by presence of valves.
Sequence of fluid flow:
: blood capillaries(blood) → interstital spaces (interstitial fluid) → lymphatic
capillaries (lymph) → lymphatic vessels (lymph) → Lymphatic trunks or ducts
(lymph) → junction of the internal jugular and subclavian veins (blood).
Two pumps that aid the return of venous blood to the heart maintain the flow
of lymph:
1. Respiratory pump:
Flow of lymph- maintained by pressure changes during inhalation.
Pressure high- flows from abdominal region (high pressure) to thoracic
region (low pressure).
