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