Exam 2 Flashcards
Functions of the lymphatic system include
Produce, maintain, and distribute lymphocytes and other lymphoid cells
Return excess fluid to bloodstream
Maintain normal blood volume
Transport hormones, nutrients, and wastes.
Eliminates variations in the composition of interstitial fluid
Transports lipids from the digestive tract
Does lymph rely on a pressure gradient to return to the heart?
yes, goes from high to low pressure.
Lymphatic vessels carry what
Carry lymph from peripheral tissues to veins in a
one way direction, no loop like blood. We are just taking excess fluid and putting it in the heart.
Primary lymphoid tissues/organs are concerned with
forming and maturing lymphocytes
Secondary lymphocytes are concerned with
where lymphocytes are activated
Why is the structure of lymphatic capillaries significant?
Because it allows for it to take in a lot of fluid to carry back to the heart.
What is problematic about the structure of the lymphatic capillaries?
They have no permeability, no basement membrane, and thinner walls.
Lack of selectivity can cause pathogens to get to the heart.
With lymphatic capillaries, there are shingles present. What is the physiology of these shingles?
High pressure causes fluid to open endothelial cell and let fluid in if the pressure Is coming from outside. Pressure build up inside endothelium will push the shingles of endothelium on to other endothelium cells.
Characteristic of the closed end nature of the capillary.
Right lymphatic duct concerns
1/4 of lymph to the top right portion of the body.
Right side above abdominal and right face.
Left lymphatic duct (thoracic duct) concerns
collects blood from 3/4 of the body
Lymphocytes make up what percent of leukocytes
20-40%
Lymphocytes are mainly ____
stored, not circulating
T cells are reliant on the
thymus
B cells are reliant on
bone marrow
NK cells
Natural killer cells
Can fight against more than one pathogen- they have a very similar development story to T and B cells and that’s why they’re considered lymphocytes.
lymphocytes are dominated by what kind of tissue?
connective tissue
Lymphoid nodules are made up of
areolar tissue with densely packed lymphocytes.
Lymphoid nodules are distributed in
nasal/oral cavity & pharynx and tonsils
Tissues(think intestines)
Small intestines - Peyer’s patches
Large intestine - Appendix
What lymphoid tissues deal with food that could carry pathogens?
MALT(Mucosa Associated Lymphoid Tissues)
Germinal center helps with
dividing lymphocytes to battle incoming pathogens
Are there more afferent vessels than efferent vessels?
Yes, because many afferent vessels are bringing in unclean lymph from all parts of the body to clean them of pathogens and only need a single efferent vessel to carry the clean lymph.
Pathway of lymph circulation in lymphatic capillaries:
Afferent Lymphatics > Subscapsular space (transports fluid) > Cortex (B cells) > Paracortex (T cells) > Medulla (Macrophages, B cells) > Efferent lymphatics
What is the significance of the structure of lymphatic organs when compared to the structure of lymphatic tissues?
Lymphatic organs have a fibrous capsule with the geminal center and such and lymphatic tissues don’t.
Function of lymph nodes
purify lymph before return to venous circulation
Remove 99 percent of antigens
Antigens released due to infection
Enter lymph and stimulate macrophages and lymphocytes in lymph nodes
Are also carried by dendritic cells to lymph nodes
Lymphoid tissues and lymph nodes
Monitor peripheral infections
Respond before infections reach vial organs.
Organs have capsules (structure)- first space you get to is the
the subcapular space.
the thymus is located in the
mediastinum
T/F, does the thymus atrophy after puberty?
T
Structure of the Thymus
Divided into two thyme lobs
Septa divide lobs into smaller lobules
There will not be any b lymphocytes
Why?: Think about whether or not it’s a primary or secondary structure
Function of the Thymus
Learning which antigen they can fight against.
Produces T cells.
Diminishes effectiveness of immune system
Functions of the spleen:
Removal of abnormal blood cells and other blood components by phagocytosis
Storage of iron recycled from red blood cells
Store some of the heme in the spleen.
Initiation of immune response by B and T cells.
Large collection of lymphocytes.
In response to antigens in circulating blood.
Synosoid capillaries-
Largest collection of lymphoid cells in the body- at risk for old RBCs floating around- at risk for infections.
White Pulp: contains lymphocytes
Red Pulp: RBCs/Macrophages
The spleen needs a lot of blood because it’s a
vascular organ
If the spleen is affected, what will happen to RBCs?
there will be a circulation of old RBCs.
Primary lymphoid organs
bone marrow, thymus
Secondary lymphoid organs:
spleen, lymph nodes, tonsils, MALT, small and large intestines.
The intertwining of veins and arteries with lymphatic capillaries is allows for
Lymphatic capillaries to pick up fluid from the bloodstream, clean it up, and bring it back to the heart for circulation.
