lymphatic system Flashcards
bio2 (107 cards)
1
Q
what is interstitial fluid called after it enters lymph vessels?
A
lymph
2
Q
who cleans the lymph that passes through it
A
lymph nodes
3
Q
what are examples of lymphoid organs and tisssues
A
spleen, thymus,
tonsils, and other lymphoid tissues scattered throughout the
body
4
Q
What pushes fluid out of capillaries?
A
Hydrostatic pressure (blood pressure inside the capillary).
5
Q
What pulls fluid back into capillaries?
A
Osmotic pressure (from proteins in the blood).
6
Q
Where does the fluid go if it’s not reabsorbed?
A
It becomes interstitial fluid and then enters the lymphatic system.
7
Q
What makes lymph capillaries able to absorb fluid?
A
They have flap-like valves that open when outside pressure is higher
8
Q
What keeps lymph from leaking back out?
A
The valves close when pressure inside is higher, so lymph flows one way only.
9
Q
Where are there no lymphatic capillaries?
A
In the bones, teeth, and most of the brain (except the meninges).
10
Q
What holds lymph capillaries open during swelling?
A
Anchoring filaments (tiny threads that pull the valves open).
11
Q
What else can enter lymph capillaries besides fluid?
A
Proteins, cell debris, bacteria, and cancer cells.
12
Q
What happens to germs in lymph?
A
they go to lymph nodes, where immune cells can destroy them.
13
Q
What are lacteals?
A
Special lymph capillaries in the small intestine that absorb fats.
14
Q
What is chyle?
A
Milky lymph full of fat, collected by lacteals.
15
Q
What is the correct order of lymph flow from smallest to largest structures?
A
Lymphatic capillaries → collecting vessels → lymphatic trunks → lymphatic ducts
16
Q
Which duct drains the right upper limb, right thorax, and right side of the head?
A
The right lymphatic duct
17
Q
What does the thoracic duct drain?
A
The entire left side of the body and everything below the ribs (both lower limbs and abdomen)
18
Q
What is the cisterna chyli?
A
A large sac at the start of the thoracic duct that collects lymph from the lower body
19
Q
Where do both lymphatic ducts empty lymph into the bloodstream?
A
At the junction of the internal jugular vein and subclavian vein on each side
20
Q
What moves lymph through lymphatic vessels since there’s no pump like the heart?
A
Skeletal muscle movement, breathing, valves, arterial pulsation, and smooth muscle contraction
21
Q
Why does lymph flow increase during physical activity?
A
Because movement helps pump lymph, and more fluid is lost from capillaries during exercise
22
Q
Why should an infected limb be kept still?
A
To reduce the spread of infection through lymphatic vessels
23
Q
What is lymphangitis?
A
Inflammation of lymph vessels, often visible as red streaks on the skin
24
Q
What causes lymphedema?
A
Blocked or damaged lymphatic vessels, which leads to swelling due to trapped fluid
25
How can tumors or surgery cause lymphedema?
They can block or remove lymphatic vessels, preventing proper lymph drainage
26
A 28-year-old woman has had breast cancer surgery. Her right arm becomes swollen weeks later.
Q: What is the likely cause of this swelling?
lymphedema due to removal of lymphatic vessels during surgery
27
A 12-year-old boy has red streaks on his arm that are painful to touch after a skin infection.
Q: What condition does he likely have?
lymphangitis – inflamed lymph vessels visible under the skin
28
A patient has blockage of the right lymphatic duct.
Q: What part of the body would swell?
The right arm, right chest, and right side of the head
29
A person lying still for a long time has slow lymph flow and increased swelling in their legs.
Q: Why?
Lack of muscle movement, which normally helps pump lymph
30
What are the two main types of lymphocytes?
T cells and B cells
31
What do T cells do?
They manage the immune response and can directly kill infected cells.
32
What do B cells do?
They become plasma cells that make antibodies, which mark invaders for destruction
33
What do macrophages do?
They eat (phagocytose) pathogens and help activate T cells.
34
What do dendritic cells do?
They catch antigens and carry them to lymph nodes to trigger an immune response.
35
What do reticular cells do?
They build the supportive network (called reticular stroma) in lymphoid tissue.
36
What is the main tissue type in lymphoid organs (except thymus)?
Reticular connective tissue
37
What two main roles does lymphoid tissue play?
Houses and activates lymphocytes
Provides a place for immune surveillance
38
What is diffuse lymphoid tissue?
Loose clusters of immune cells, found in many organs, especially mucous membranes
38
What is a lymphoid follicle (or nodule)?
A tight cluster of lymphoid cells; may contain a germinal center where B cells divide.
39
Where are lymphoid follicles found?
in lymph nodes, Peyer's patches, and the appendix.
40
What are the primary lymphoid organs?
Red bone marrow (B cells mature here) and thymus (T cells mature here)
41
What are the secondary lymphoid organs?
Lymph nodes, spleen, and MALT (e.g. tonsils, Peyer’s patches, appendix)
42
here do lymphocytes first meet antigens?
In secondary lymphoid organs
43
Which lymphoid organ filters and cleans lymph?
Lymph nodes
44
Which lymphoid organs lack afferent lymphatics but have efferent ones?
Spleen, tonsils, Peyer’s patches, and appendix
45
A child has an underdeveloped thymus and keeps getting viral infections.
Q: What immune cell is likely not maturing properly?
T cells
46
A biopsy shows lymphoid follicles with large germinal centers.
Q: What is happening in those centers?
B cells are rapidly dividing and forming plasma cells.
47
A patient’s lymph nodes are swollen after a viral infection.
Q: Why did the lymph nodes swell?
Because T and B cells are being activated by antigens.
48
After appendix removal, the patient still has Peyer’s patches.
Q: What is their role?
To monitor intestinal pathogens using lymphoid follicles.
49
What are the two main functions of lymph nodes?
cleansing the lymph (via macrophages)
Activating the immune system (via T and B cells)
50
Where are large clusters of lymph nodes found?
In the inguinal, axillary, and cervical regions.
51
What cells filter debris and microorganisms in the lymph?
Macrophages
52
What type of immune cell is activated in lymph nodes by dendritic cells presenting antigens?
T cells
53
What is the capsule of the lymph node made of, and what does it send inside the node?
A fibrous capsule with inward trabeculae that divide the node into compartments.
54
What kind of connective tissue forms the lymph node’s supportive framework?
Reticular connective tissue (stroma)
55
What are the two main regions of a lymph node?
The cortex (outer) and the medulla (inner)
56
What cells are mostly found in the germinal centers of follicles in the cortex?
B cells
57
What cells are found mostly in the deeper cortex and medulla?
T cells
58
Through what vessels does lymph enter a lymph node?
Afferent lymphatic vessels
59
What structures allow lymph to flow slowly through the node for immune surveillance?
Lymph sinuses (e.g., subcapsular and medullary sinuses)
60
Through what vessel does lymph exit a lymph node?
Efferent lymphatic vessel, located at the hilum
61
Why does lymph flow slowly through the node?
Because there are fewer efferent vessels, allowing more time for immune cells to act.
62
What is lymphadenopathy?
Swollen lymph nodes, usually due to infection or immune activity.
63
What is a bubo?
A pus-filled, infected lymph node, seen in serious infections like bubonic plague.
64
How do cancerous lymph nodes differ from infected ones?
Cancerous nodes are swollen but not painful; infected nodes are tender and sore
65
A patient has a tender, swollen node in the neck after a throat infection.
Q: What is this condition, and what cells are most active?
Lymphadenopathy; macrophages and lymphocytes are actively fighting infection
66
A patient’s axillary lymph node is enlarged but painless. They had breast cancer surgery last year.
Q: What might this indicate?
Possible metastasis—the lymph node may be a secondary cancer site.
67
A diagram shows B cells multiplying in a germinal center inside a lymph node.
Q: Which region of the node is this?
The superficial cortex (in a follicle)
68
a biopsy of a node shows high T-cell activity and dendritic cells presenting antigens.
Q: Where in the lymph node is this likely happening?
In the deep cortex (paracortex)
69
What is the spleen's main role?
It filters blood, removes old RBCs, stores immune cells, and supports immunity.
69
What cells remove debris in the spleen?
Macrophages
69
Where is the spleen located?
On the left side under the diaphragm, near the stomach.
70
What are 3 additional functions of the spleen?
Recycles RBCs and iron
Stores platelets and monocytes
Makes RBCs in the fetus
71
What are the two tissue types in the spleen?
White pulp – contains lymphocytes and does immune functions
Red pulp – destroys old RBCs and pathogens, contains macrophages and RBCs
72
What surrounds and supports the spleen?
A fibrous capsule with trabeculae and reticular fibers
73
What can happen if the spleen is ruptured?
Internal bleeding and possible splenectomy (removal)
74
Can the spleen repair itself?
Yes, especially in children or if part is left behind—it may regenerate
75
What organs take over if the spleen is removed?
The liver and bone marrow
76
What does MALT do?
Protects mucous membranes from pathogens (like in the digestive or respiratory tract)
77
What are 3 major MALT organs?
tonsils
Peyer’s patches
Appendix
78
What is the function of tonsils?
Trap and destroy pathogens from air and food entering the pharynx
79
What are tonsillar crypts?
Pockets that trap bacteria—stimulating immune memory in children
80
Name the types of tonsils and locations:
Palatine – sides of oral cavity
Lingual – base of tongue
Pharyngeal – back of nasopharynx (aka adenoids if enlarged)
Tubal – near auditory tubes
81
Where are Peyer’s patches located?
In the wall of the small intestine (especially distal ileum)
82
What is Peyer’s patches function?
Prevent bacteria from crossing the gut wall and help form immune memory
83
What is the appendix and what does it do?
a tube off the large intestine rich in lymphoid follicles; helps stop bacteria and builds memory lymphocytes
83
A child has their tonsils removed due to chronic infections.
Q: Which kind of immunity might be mildly affected long-term?
Their ability to form early immune memory via tonsillar crypt exposure
84
An accident ruptures the spleen of a 10-year-old. A small piece is left behind.
Q: Can the spleen regrow?
Yes, in children under 12, the spleen can regenerate
85
A biopsy of intestinal tissue shows many lymphoid follicles near the ileum.
Q: What are these likely to be?
Peyer’s patches
86
A patient has no spleen. What organs now handle the spleen’s jobs?
A: The liver and bone marrow take over most immune and blood-filtering functions
87
What is the main role of the thymus?
It matures T lymphocytes, making them immunocompetent (able to respond to antigens).
88
Where is the thymus located?
In the inferior neck and upper thorax, just above the heart and behind the sternum
89
When is the thymus most active?
During early childhood; it grows until puberty, then slowly atrophies.
90
Does the thymus continue functioning in old age?
Yes, but at a reduced rate—it still produces T cells.
91
What are the two main regions of a thymic lobule?
Cortex – dense with dividing T cells
Medulla – lighter area with fewer lymphocytes and thymic corpuscles
92
What are thymic corpuscles?
Whorls of keratinized epithelial cells that help form regulatory T cells, which prevent autoimmune reactions.
93
Why does the thymus not fight infections directly?
It has no B cells, no follicles, and uses a blood-thymus barrier to keep foreign antigens out.
94
What kind of cells form the thymic stroma (support network)?
Epithelial cells, not reticular cells like in other lymphoid organs.
95
What is the purpose of the blood-thymus barrier?
It protects developing T cells from exposure to antigens too early.
96
When do lymphatic vessels first form in the embryo?
Around the 5th week of development
97
From where do lymph sacs and vessels develop?
They bud from developing veins and spread to form the thoracic and lymphatic ducts.
98
What do lymphoid organs (except thymus) develop from?
Mesodermal mesenchymal cells, which become reticular tissue
99
What is unique about the embryonic origin of the thymus?
It comes from endoderm (primitive pharynx), unlike other lymphoid organs.
100
When are lymphoid organs populated by lymphocytes?
Shortly after birth
101
A child with DiGeorge syndrome lacks a functional thymus.
Q: What immune cells would be deficient?
T lymphocytes—they would not mature properly.
102
An elderly person has almost no visible thymus on imaging.
Q: Should this be concerning?
No, the thymus naturally shrinks with age (atrophy) and is replaced by fat.
103
biopsy of a lymphoid organ shows epithelial cells supporting T cell maturation.
Q: Which organ is this?
the thymus, not a secondary lymphoid organ.
