Lecture 3 A: The Lymphoid Organs and Lymphatic System Flashcards
What are the primary (central) lymphoid organs?
- Bone marrow
- Thymus
What are the secondary (peripheral) lymphoid organs?
- Lymph nodes
- Spleen
- Peyer’s patches
- Adenoid
- Tonsils
-Bone marrow (technically)
What is the function of the secondary lymphoid organs?
Lymphocyte localization and activation
What is the function of the primary lymphoid organs?
Leukocyte development; where they originate from and mature.
The lymphoid organs include the ______ system in combination with the _______ system.
lymphatic; cardiovascular
Where do leukocytes develop in rabbits, ruminants, and pigs?
Intestinal lymphoid tissue
Where do leukocytes develop in primates and rodents?
The bone marrow
Where do leukocytes develop in avain?
the bursa of fabricius
Where are secondary/peripheral lymphoid organs located?
throughout the body
The secondary/lymphoid tissues have ___ concentrations of B and T cells.
high
Secondary lymph nodes are sites of immune activation through a process of _______.
priming
Leukocytes refer the what type of immune cells?
Any type of immune cells
Lymphocytes refer mainly to ___ and ___ cells of the ____ immune system.
B and T cells; adaptive immune system
What is the third type of lymphocyte, and why is it not usually grouped in with B and T cells?
Natural killer cells. They are usually not included with leukocytes because they are part of the innate immune sys., while B and T cells are part of the adaptive immune sys.
What is the largest type of blood vessel?
Artery
How do leukocytes circulate around the body?
They travel through the vascular and lymphatic systems
What does the vascular system circulate throughout the body?
blood
What does the lymphatic system circulate throughout the body?
lymph
A small pre-B cell that is ready to leave the bone marrow uses what receptor to signal its release?
IgM
What does a small pre-B cell undergo to be released to the peripheral lymphoid organs?
Alternative splicing
Some pre-B cells will start to express _____ receptors with the same specificity as those with IgM
IgD
Where do naive B cells mainly hang out in the secondary lymphoid tissue?
in primary lymphoid follicles
How do naive B cells enter the spleen?
through blood
How do naive B cells enter the lymph nodes?
through the lymphatic system
Primary lymphoid follicles contain what type of cells?
Follicular dendritic cells
Follicular dendritic cells only capture antigens that are brought in by ______.
lymph
What are the GALT lymphoid organs?
Peyer’s patches, tonsils, and appendix
What synthesis do the GALT lymphoid organs participate in?
IgA synthesis
What are _ important functions of the lymph system for immune response?
- maintain fluid balance in the body by draining excess fluid from tissues
- absorb dietary fats from the intestines,
- filtering out harmful substances
- producing white blood cells to fight infection
Lymphocytes circulate between lymph and blood under the direction of _____ and ______.
Addressins (adhesion molecules) and chemokines
What are other terms for lymphocyte circulation?
Lymphocyte homing
Lymphocyte trafficking
(These are terms used to describe what carries lymphocytes to different areas)
About what percent of nucleated cells in the blood are lymphocytes?
About 30%
About what percent of nucleated cells in lymphatics are lymphocytes?
Over 99%
How/when is lymph formed?
When fluid leaves the capillaries and goes to the interstitial space. It bathes tissues (????), and is collected in lymphatic vessels.
