Overview of the lymphatics system Flashcards
What is the lymphatics system?
Fluid conducting system
Transports lymph in vessels connected by nodes
What is lymph?
Clear, watery fluid made from reabsorbed interstitial fluid
Function of the lymph
Drains excess interstitial fluid to maintain circulating volume and blood pressure
Transports dietary lipids and lipid soluble vitamins
Immune response
Where are lymphatic capillaries found?
Everywhere except avascular tissue, CNS, spleen and bone marrow
Where are lacteals found?
Small intestine
What do lacteals do?
Carry dietary lipids to lymphatic vessels
What do anchoring filaments do?
Attach lymphatic endothelial cells to surrounding tissues. When pressure rises, the cells separate so fluid can pass through
Characteristics of lymphatic capillaries
Has both lymphatic and venous component Drain fluid outside cells Endothelium opens so fluid can permeate Located between cells, one end is open Overlap to ensure one way flow of lymph
Flow chart passage of lymph
Lymph capillary - lymph vessel - lymph node - lymph trunks - lymph disks
What are the two pumps that help move lymph?
Skeletal muscle pump and respiratory pump
How does the skeletal muscle pump help move lymph?
Milking action caused by skeletal muscle contractions
How does the respiratory pump help move lymph?
In inhalation, lymph travels down pressure gradient from abdomen to chest
What are the five lymph trunks?
Jugular Subclavian Bronchomediastinal Intestinal Lumbar
Where are the jugular lymph trunks located?
Head and neck
Where are the subclavian lymph trunks located?
Upper limbs
Where are the bronchomediastinal lymph trunks located?
Thoracic wall, lung and heart
Where are the intestinal lymph trunks located?
Liver, stomach, intestine, pancreas
Where are the lumbar lymph trunks located?
Lower limbs, pelvis, kidneys, adrenal glands, abdominal wall
How long is the thoracic duct?
40 cm
What does the thoracic duct originate as?
Dilation cisternachyli
Where does the thoracic duct receive lymph from?
Lower limbs, lumbar trunks, intestine, left jugular, left subclavian, left bronchiomediastinal
Where does the thoracic duct drain lymph from?
Right jugular, right subclavian, right bronchiomediastinal
How long is the right lymphatic duct?
1.2 cm
When are the right lymphatic duct and left thoracic duct commonly injured?
Neck dissections to remove cancerous lymph nodes
What are venous angles?
Site of drainage of lymphatic ducts
Junction of internal jugular vein and subclavian vein bilaterally
What are primary lymphatic organs?
Sites where stem cells divide and become immunocompetent
Where do stem cells come from?
Red bone marrow
What are the two primary lymphatic organs?
Bone marrow and thymus
What are secondary lymphatic organs?
Where immune response happens - they house lymphocytes
Where are Peyer’s patches found?
Intestine
What are the secondary lymphatic organs?
Lymph nodes, spleen, lymph nodules
What does MALT stand for?
Mucosa Associated Lymphatic Tissue
Adenoids in phalangeal tract
What shape are lymph nodes?
Kidney
What do lymph nodes do?
Filter lymph as it enters
They trap particles with fibres
Where are lymph nodes found?
Throughout the body, can be superficial and deep
How does waste leave the lymph nodes?
Efferent vessels
Why does lymph only flow in one direction through the lymph nodes?
Valves
What does the thymus processing organ do?
Makes T cells immunocompetent
Where do B cells develop and mature?
Bone marrow
Where do T cells develop?
Bone marrow
Where do T-cells mature?
Thymus
Characteristics of spleen
Red and white pulp
Left hypochondrium
Secondary lymph organ
Functions of spleen
Immune response, degrade and store RBCs, store platelets, haematopoeisis in fetus
What are adenoids?
Nasopharyngeal tonsils
Where are adenoids located?
Behind nose, posterior opening of nasal cavity, roof of posterior wall of pharynx
What is filariasis?
Soft tissue full of blocked lymphatic tissue
What are Peyer’s patches?
Aggregated lymphatic follicles
How much fluid does the lymphatic system return to the body each day?
3 litres
How can lymph vessels be blocked?
Infection and fibrosis - microfilaria Bancrofti
Life cycle of microfilaria bancrofti?
Microfilaria enter the mosquito
Develop into infected larvae
Injected into new host
Mature into worms and spread throughout lymphatic system
