CHAPTER 21 LYMPHATIC SYSTEM BY MP
Lymphedema
(swelling) is recognized as an accumulation of interstitial fluid that occurs due to interference with lymphatic drainage in a part of the body.
primary structures are
RED BONE MARROW AND THYMUS
lymph nodes
filtration: macrophages destroy microorganisms and debris
lymph trunks and Ducts
lymph drains from lymphatic trunks into two lymphatic ducts (right lymphatic duct and thoracic duct) that empty into the junctions
lymphatic vessels
lymphatic capillaries merge to form larger structures that are called lymphatic vessels
lymphatic capillaries
merge to form larger lymph vessels
immune system activation
monitor for antigens and mount an attack against them
blood flow trough the spleen
Blood enters at the hilium via the splenic artery Travels through the central arteries to the white pulp Examined for foreign substances/pathogens Blood then travels to the red pulp via the sinusoids Macrophages destroy old cells, pathogens, foreign particles Sinusoids merge to form venules which merge again to form the splenic vein
enlarged lymph nodes
Could be sign of: Infection Cancer Can indicate metastasis of cancer Hodgkins Lymphoma Reed Sternberg cells Non-Hodgkins Lymphoma More common Abnormal B-Cells
lymph through lymph nodes
Enters via afferent lymphatic vessels and travels through the sinuses Macrophages remove debris/pathogens Lymph exits via the efferent lymphatic vessel This vessel then takes the lymph to another node in the cluster The process is completed numerous times If a foreign substance/pathogen is encountered, then lymphocytes are activated Some stay in node; others travel in vasculature to site of infection
lymphatic collecting vessels
Have the same three tunics as veins Have thinner walls, with more internal valves Anastomose more frequently Collecting vessels in the skin travel with superficial veins Deep vessels travel with arteries Nutrients are supplied from branching vasa vasorum
lymph movement into capillaries
Increases hydrostatic pressure in interstitial space due to increase in fluid buildup from blood. pressure pushes fluid into lymphatic capillaries capillaries are protected from collapse by anchoring filaments.
spleen
Largest lymphoid organ Location On the left side of the abdominal cavity beneath the diaphragm Functions: Site of lymphocyte proliferation Immune surveillance and response Cleanses the blood Stores breakdown products of RBCs for later reuse Spleen macrophages salvage and store iron for later use by bone marrow Site of fetal erythrocyte production (normally ceases after birth) Stores blood platelets
lymphatic nodules and malt
Lymphatic Nodules Lymphatic follicles - small oval clusters of lymphatic cells with some extracellular matrix Scattered nodules - alled diffuse lymphatic tissue and found in every body organ and within the appendix MALT (mucosa associated lymphatic tissue) Located in lamina propria of the mucosa of the GI, respiratory, genital, and urinary tracts Help defend against foreign substances coming in contact with the mucous membranes
peyer patches
Lymphatic nodules Isolated clusters of lymphoid tissue, similar to tonsils Found in the wall of the ileum of the small intestine Similar structures are found in the appendix Function to protect from never-ending attack of pathogens in the body
Lymphoid cells
Lymphocytes are the main cells involved in the immune response Two main varieties: T cells Manage the immune response B cells Produce plasma cells, which secrete antibodies which immobilize antigens Antigens - anything the body perceives as foreign
Other lymphoid cells
Macrophages Phagocytize foreign substances and help activate T cells Dendritic cells Spiny-looking cells with functions similar to macrophages Found in skin
tonsils
Pharyngeal tonsils - posterior wall of nasopharynx When enlarged called adenoids Palatine tonsils - posterolateral region of oral cavity Lingual tonsils - along the posterior one-third of the tongue
thymus associated with the lymphatic siystem
Primary structure. Location: Superior mediastinum (in adults) anterior and superior mediastinum in children FUNCTION: SITE OF T-LYMPHOCYTE MATURATION AND DIFFERENTIATION
lymphatic tissue and organs are categorized as either primary or secondary structures
Primary structures are involved in the formation and maturation of lymphocytes.
MALT (mucosa associated lymphatic tissue
Secondary structure, Location: within walls of gastrointestinal GI tract respiratory, reproductive , and urinary tracts, FUNCTIONS: initiate an immune response that comes in contact with a mucosa membrane
Lymph nodes
Secundary structure, Location: Along length of lymphatic vessels; clusters are present in axillary , inguinal, and cervical regions FUNCTIONS: filter lymph; where immune response is initiate against a substance in the lymph.
Spleen organ associated the lymphatic sytem
Secundary structure, Location: left upper quadrant of abdomen near 9th- 11th ribs, "wraps" partway around stomach. FUNCTIONS: filters blood : where immune response is initiate against a substance in the blood; removes aged erythrocyte and platelets; serves as platelet reservoir.
Tonsils
Secundary structure, Location: within pharynx (throat), FUNCTIONS: protect against inhaled and ingested substances
Thymus produces
T-cells o t-lymphocytes
lymph is carried back to circulatory system via 2 lymphatic ducts, connected to the subclavian veins
Th right side of the duct drains the right side head, neck and entire right upper extremity.
Thoracic Duct
The larger of the two lymphatics ducts is the thoracic duct. it has a length of about 37.5 to 45 centimeters
lymphatic capillaries
The lymph vessels begin with lymphatic capillaries which are the smallest lymph vessels, similar to blood capillaries.
Overview of lymphatic tissue and organs
The lymphatic system also is made up of specialized lymphatic tissue and organs.Including red bone marrow, the thymus, lymph nodes the spLeen, tonsils, MALT.
lymphatic system
The lymphatic system is made up of both lymph vessels and lymphatic tissue and organs. lymphatic tissue and organs are organized into primary and secondary structructures.
lymphatic transport
The lymphatic system lacks a pumping organ Vessels are low-pressure conduits Uses the same methods as veins to propel lymph Pulsations of nearby arteries Contractions of smooth muscle in the walls of the lymphatics
Secondary structures are
are not involved in lymphocyte formation. secondary lymphatic structures are lymph nodes, spleen, tonsils, lymphatic nodules.
valves
are required to prevent lymph from pooling in the vessel and help to prevent lymph backflow because the lymph vessel network is a low pressure system.
in contrast deep lymphatic vessels are next to deep
arteries and veins
lymph node
become inflame during infections .
lymphatic capillaries can absorb:
cell debris, pathogens cancer cells , they are microscopic closed-ended vessels that absorb interstitial fluid.
lymphatic system transport
chylomicrons are packages of lipids cholesterol and small amount of protein
lymph from intestinal trunk and lumbar lymphatic trunks flows into the
cisterna chyli located in the thoracic area
lymph nodes are located in
clusters throughout the body.
white pulp
contain white blood cells(macrohages, lymphocytes) fight infection
lymphatic system transport
dietary fats, protects invasion through non-specific defenses and the immune system
anchoring ligament
help hold theses endothelial cells to the nearby structures
Spleen
helps in recycling red blood cells immunity
components of lymph(clear spring water)
include water, dissolved solutes, small amount of protein approximately 100 to 200 grams of leaked into the interstitial space during capillary exchange, possibly cell debris, pathogens, and perhaps metastasized cancer cells
Source
interstitial fluid surround tissue cells 15% that was not reabsorbed by capillaries following filtration reabsorption
lymph originate as
interstitial fluid surrounding the tissue cells
lymphatic vessels resemble small veins because both contain all three vessels tunics
intima, media and externa and have valves into their lumen
Components of lymphatic system
is composed of lymph vessels and lymphatic tissues and organs.
Right lymphatic duct
is located near the right clavicle receives lymph from the lymphatic trunks that drain the following areas: the right side of the head and neck, the right upper limb, and the right side of the thorax. The right lymphatic duct drains lymph from upper right quadrant of the body.
lymphatic capillaries located within the gastrointestinal GI tract called
lacteals (milk) allow for the absorption of lipid-soluble substances from GI tract.
Locations of the lymphatic nodes are
located in cervical lymph nodes, axillary lymph nodes , pelvic lymph node, inguinal lymph node, lumbar lymph node
functions of lymphatic system
lymph is the fluid transported within lymph vessels. return interstitial fluid and leaked plasma proteins back to the blood. immunity, transport dietary fats
complete capsule are
lymphatic organs such as nodes and spleen
lymph trunks and ducts
of the right jugular and right subclavian veins and left jugular and subclavian veins respectively.
lymph movement into capillaries
once inside the increased fluid exerts opposing pressure and the flaps close which traps lymph inside capillary.
lymphatic capillaries functions as
one way gates. lymph capillaries connect to lymphatic vessels.
fluid flows one way into capillary by way of a
pressure gradient
red pulp
recycles red blood cells
spleen contain
red and white pulp
primary lymphatic structures
red bone marrow produces all formed elements through the process of hemopoiesis. immature t-lymphocytes migrate from bone marrow to the thymus to complete the maturation
lymphatic structures
red bone marrow=primary structure Location: spaces in spongy bone within certain bones. FUNCTION: Formation: of all formed elements.
blood capillaries and lymph capillaries
resembles the anatomic structure of a blood capillary in that its wall is composed of an endothelium however, lymphatic capillaries are typically larger in diameter that blood capillaries.
Lacteals
specialized lymph capillaires present in intestinal mucosa
lacteals
specialized lymph capillaries present in intestinal mucosa: absorb digested fat and deliver chyle to the blood
superficial veins of the body are generally positioned adjacent to the
superficial veins of the body
The right side of the body drain
the rest of the boby
incomplete capsules are
tonsils, MALT, and diffuse lymphatic nodules
digestive system cells package lipids into chylomicrons
transported in lymph via lacteal located in the intestinal villae