Lymphatic System

What is interstitial fluid?

fluid that is pushed out of vessels and into the tissues

Where is most interstitial fluid returned to?

venous system

What is lymph?

interstitial fluid that is picked up by the lymphatic system - fluid connective tissue

What is the lymphatic system composed of?

lymph vessels, lymphoid tissues, and organs

What are the functions of the lymphatic system?

return interstitial fluid back into the blood stream, initiate immune response when necessary, and transport dietary lipids

What is the lymphatic flow order?

lymphatic capillaries -> lymphatic vessels -> lymphatic trunks -> lymphatic ducts

What are lymphatic capillaries

smallest of lymph vessels

What are lymphatic capillary walls composed of?

Endothelium

What are lacteals?

lymphatic capillaries in the small intestine

What is the function of lacteals?

carry interstitial fluid, dietary lipids (fats), and some vitamins

What is the function of lymphatic vessels?

take lymph to and from lymph nodes

What is the composition of lymphatic vessels?

3 layers (tunics) and valves

What are lymphatic trunks formed from?

merging lymphatic vessels

What do lymphatic trunks drain into?

lymphatic ducts

What are the two lymphatic ducts?

right lymphatic duct and thoracic duct

Where does the right lymphatic duct receive lymph from?

right side of head, neck, thorax and right upper limb

Where does the right lymphatic duct drain into?

right subclavian vein

Where does the thoracic duct receive lymph from?

left side of head, neck, thorax, left upper limb, entire abdomen, and left/right lower limbs

Where does the thoracic duct drain into?

left subclavian vein

What is innate immunity?

nonspecific defense mechanisms that are present at birth

What is adaptive immunity?

defense mechanisms developed in response to contact with antigens

What is an antigen?

anything perceived as foreign in the body

What are antibodies?

attach to antigens and immobilize them until another cell destroys the antigens

What are macrophages?

monocytes that migrated from the bloodstream into other tissues

What is the function of macrophages?

phagocytize foreign substances and may present antigens to other cells

What is the function of dendritic cells?

internalize antigens and present them to lymphocytes

What is the function of epidermal dendritic cells?

phagocytize foreign debris, bacteria, and epidermal cancer cells

What are lymphatic nodules?

"clumps" of lymphoid cells within other organs

What is an example of lymphatic nodules?

MALT (mucosa-associated lymphoid tissue)

What is the difference between lymphoid structures and lymphoid organs?

organs are surrounded by a connective tissue capsule whereas structures are not

What are the functions of lymph nodes?

filter lymph (macrophages eat up foreign matter) and activate immune system if antigens are found in lymp (antigens T- and B- cells into action)

What is the function of the thymus?

to secrete hormones to help with t-lymphocyte development and differentiation

What is the largest lymphoid organ in the body?

spleen

What are the two parts of the spleen?

red pulp and white pulp

What cells are located in the red pulp?

erythrocytes, platelets, and macrophages

What is the function of the red pulp?

to remove old erythrocytes and macrophages

What cells are located in the white pulp?

lymphocytes

What is the function of the white pulp?

to carry out an immune response when antigens are found in blood

Where is red pulp located?

splenic sinusoids (large capillaries) and splenic cords

Where is white pulp located?

surrounds arterial branches