Chapter 28: Lymphatic System Flashcards
What are the functions of the lymphatic system?
- ) Produce, maintain, and distribute lymphocytes
- ) Maintain normal blood and interstitial fluid volume
- ) Alternate route for the transport of materials
- Nutrients
- Hormones
- Waste
lymphatic vessels transport fluid called ______ from tissues to the _______
lympth; venous system
lymphatic vessels can range in size… give some examples (4)
Small lymphatic capillaries
Medium lymphatic vessels
Large lymphatic trunks
Lymphatic ducts
lymphatic vessels are almost always found associated with _________
blood vessels
lymphatic vessels are found where?
absent where?
Found in most tissues
Absent in avascular tissue and the CNS
what is lymph?
Lymph is a fluid connective tissue
It occurs ONLY in the lymphatic vessels
what is lymph derived from?
Interstitial fluid of the tissues
Lymphocytes
Macrophages
Slide 6
:)
describe lymphatic capillaries (5)
- Closed ended tubes
- In interstitial spaces
- Form networks
- Single layer of squamous cells with incomplete basal lamina
- fenestrated
How are lymphatic capillaries different from blood capillaries? (5)
- Larger diameter
- Thinner walls
- Flat and irregular
- Have anchoring filaments to keep the passage open
- Overlapping endothelial cells
describe the formation of lymph
Interstitial fluid enters capillaries
- Overlapping cells function as one way valves
- Moves through fenestrations
- Large things such as viruses and debris follow
describe medium lymphatic vessels
Merging of lymph capillaries Similar to veins -Interna -Media -Adventitia -Valves Merge to form trunks Travel with arteries of same size
__________ are named for the _______
examples?
Lymphatic Trunks, region they drain
Ex. Lumbar, Intestinal, Broncomediastinal, Subclavian, Jugular
____ drain into _______
Trunks; Ducts
what are the two lymphatic ducts?
thoracic and right lymphatic
What do lymphatic ducts do?
Deliver lymph to venous circulation at subclavians
- Reintroduced to bloodstream
- Becomes part of plasma and is circulated
where does the thoracic duct drain?
drains lower body, left arm, head & neck
describe the route of the thoracic duct
arises from cisterna chyli
through diaphragm
ascends in front of vertebral column
empties into left subclavian vein
where does the right lymphatic duct drain?
drains right side of head, neck & right arm
describe the route of the right lymphatic duct
starts in right thorax
To the right subclavian vein
lymphatic ducts (Evenly/Unevenly) drain fluid from body
explain?
Unevenly;
Thoracic does the majority
It is much longer and drains the entire inferior half of the body
describe the movement of lymph
Contain valves -Occur at bulges -Prevent backflow --Pressure is lower in lymphatics than in veins) --Lymph is moved using similar methods to veins) ---Skeletal muscles ---Breathing (slide 16)
What is it called If drainage does not occur?
lymphedema
Primary cells of the lymphoid system are called what?
lymphocytes
Lymphocytes allow for……
specific (or adaptive) immunity
-multi-faceted immune response to the detection of specific foreign antigens
when it comes the lymphocytes what are the three cells?
T cells
B Cells
NK Cells
describe NK cells (4)
- Natural killer (NK) cells
- Derived directly from bone marrow
- NON-specific immunity
- Detect chemical signals other than specific antigens (like all the other leukocytes) and induce apoptosis
describe B cells (3)
- Originate and develop in the bone marrow (B-cells)
- Stimulated by an antigen to produce antibodies
- Can survive for years as memory cells, and become active once exposed to a similar antigen
describe T cells (4)
- Originate in the bone marrow but develop in the thymus (T-cells)
- Attack cells with antigens indicating viral infection or detrimental mutations (cancer)
- Induce apoptosis
- Have memory cells similar to B-cells
what are lymphoid nodules?
Reticular connective tissue dominated by lymphocytes
**NOT organs
what is M.A.L.T
(Mucosa associated lymphoid tissue)
Digestive lymph nodules
where are tonsils positioned and what do they do?
- Positioned around the pharanx
- Remove pathogens that enter via air or food
what are the three types of tonsils? describe
- ) Pharyngeal tonsil
- one nodule in nasophranx
- a.k.a. adenoids - ) Palatine tonsils
- two nodules on the soft palate - ) Lingual tonsils
- two nodules at the base of the tongue
what MALT lines mucosa of the small intestine
Aggregated lymphoid nodules
what is the appendix?
Blind tube at the beginning of small intestine
Area prone to infection
-Appendicitis
-Intestinal flora enter underlying tissues
lymphatic organs are surrounded by…..
a fibrous, connective tissue capsule
what are the three lymphatic organs?
Thymus
Spleen
Lymph Nodes
describe lymph nodes (3)
-bean shaped
-Between several afferent and one efferent vessel
-Hilus
(indented region where BV’s, nerves, and efferent lymph vessels connect)
lymph nodes have a cortex and medulla.. describe both sections
Cortex: -capsule has trabeculae that subdivide it Has two regions: outer cortex (consists of aggregated B-cells) inner cortex (T cells enter blood here)
Medulla:
B-cells leave through the efferent vessel
what are the 6 locations of lymph nodes?
Cervical Axillary Inguinal Pelvic Abdominal Thoracic
Where is the spleen located?
the left side of the stomach
True or False: the spleen is the largest lymphatic organ
true
the spleen is made up of 2 types of pulp… what are they and describe them
White pulp -resembles lymph node Red pulp -large amounts of RBC -sinuses, macrophages, T/B cells
what are the functions of the spleen? (5)
Remove old RBC’s Store/recycle iron Initiate immune response Blood reservoir RBC production in fetus
where is the thymus located?
in mediastium
describe the size and development of the thymus over time as you age
first lymph organ to develop
grows until puberty
Shrinks with age
replaced by fibrous & adipose tissue
the thymus has 2 lobes with lobules. what are they?
Cortex-mostly immature T-cells
Medulla-mostly reticular epithelial cells
describe the T cells in the thymus
Cortex produces T-cells
Mature and migrate into medulla
Enter blood vessels and go into circulation
describe reticular cells in the thymus
Produce thymosin
Promote T-cell differentiation
