Lymphatic System Flashcards
Capillary Level
Fluids pushed OUT of vessels and into the tissues
Interstital Fluid
Fluid within tissues
Venules job in Lymphatic System
Pick up most, but not ALL of this fluid
Lymph
interstitial fluid picked up by the lymphatic system
Lympathatic System consists of…
lymph vessels and lymphatic tissues and organs
Functions of Lymphatic System
Return interstitial fluid back to bloodstream
Can initiate an immune response when necessary
Lymphatic Capillaries
Smallest of lymph vessels
- Wall composed of endothelium
- The walls have 1-way flaps
- Lacteals
Lymphatic Capillaries; Lacteals
Lymphatic capillaries in small intestine
Lymphatic Capillaries; Lacteals Function
In addition to carrying interstitial fluid, they also carry dietary lipids (fats and some vitamins)
Lymphatic Vessels
Like veins, they have 3 tunics
- *Have valves
- Lymphatic vessels take lymph to and from lymph nodes
Lymphatic Trunks
*formed from merging lymphatic vessels
Right Lymphatic Duct
receives lymph from:
- Ride side of head, neck and thorax,
- Right upper limb
- Drains into right subclavian vein
Lymphatic Ducts Components
Right Lymphatic Duct
Thoracic Duct
Thoracic Duct
Receives lymph from:
- Left side of head, neck, thorax
- left upper limb
- entire abdomen, left and right lower limbs
- drains into left subclavian vein
Lymphedema Clinical
This swelling is caused by blockage of lymphatic vessels. Result in increased interstitial fluid
Innate Immunity
The defense mechanisms present at birth
Adaptive Immunity
Those defense mechanisms which are developed in response to contact with antigens
Antigen Definition
Anything perceived as foreign in body
These cells start and produce immune response when exposed to antigens
Lymphocytes
**T-Lymphocytes (T-Cells)
**B-Lymphocytes (B-CellS)
Macrophages
T-Lymphocytes (T Cells)
- functions: some of these cells manage/direct an immune response, while others directly attack cells
- Essentially receive cytokine that activate B and Macrophages. Attach and start countdown for how long until they die
B-Lymphocytes (B-Cells)
- function: many of these cells secrete antibodies
- antibodies attach to antigens and immobilize them until another cell destroys antigen
- *Activates killer T-Cells and B-Cells
Macrophages
macrophages are monocytes that migrated from bloodstream into other tissues
* Function: phagocytize (eat up) foreign substances
Lymphatic Structures
- Consists of connective tissue containing lots of lymphatic cells
- NOT surrounded by a CT capsule
Lymphatic Nodule
“clumps” of lymphatic cells within other organs
- example:
1) MALT
MALT
(mucosa-associated lymphatic tissue): collections of lymphatic nodules in GI, respiratory, and genitourinary tracts
* The cells here “destroy” bacteria before they breach the intestinal wall also generate “memory” cells
Lymphatic Organs
Lymphatic structures surrounded by a connective tissue capsule
Lymphatic Organs Components
Lymph Nodes
Thymus
Spleen
Lymph Nodes
- tiny oval organs
- hundreds
- found in “clusters”
- they connect with lymphatic vessels:
Lymph Nodes Functions
1) Filter Lymph
* macrophages eat up foreign matter
2) Activate immune system if antigens are found in lymph
* antigens stimulate T and B cells into action
Thymus Location
Behind Sternum
Thymus Functions
T-Cells mature and differentiate here
- immature T-lymphocytes are sent from bone marrow into the thymus
- the thymus secretes hormones to help the T-lymphocytes develop
- there, the T-lymphocytes decide what they want to do when they grow up
Spleen Description and Location
largest lymphatic organ in body
* located in upper left abdomen, behind and lateral to stomach
Two Components of Spleen
Red Pulp
White Pulp
Red Pulp
Splenic sinusoids (large capillaries) and splenic cords *Contains erythrocytes, platelets and macrophages
Red Pulp Function
Removal of old erythrocytes (RBCs) and platelets
** macrophages break down the old cells, and takes the reusable parts for recycling (e.g. - “heme” part)
White Pulp
Lymphocytes (B+T CellS)
White Pulp Function
Carry out an immune response, when antigens are found in blood
The thymus largely regresses (breaks down) by adulthood. Why do you think that might be? How do our immune systems still work?
We no longer need these when we are adults so the body will break it down and replace that area with fat.
