Lymphatic System

Lymphatic system

Circulate bodily fluid called lymph

Transport fluid away from interstitial spaces

Launch attacks against foreign substances, protects against disease

Lacteals

Special lymphatic capillaries → absorb digested fats and transport to venous circulation

Location: lining of small intestine

Lymphatic system

Circulate bodily fluid called lymph

Transport fluid away from interstitial spaces

Launch attacks against foreign substances, protects against disease

Lacteals

Special lymphatic capillaries → absorb digested fats and transport to venous circulation

Location: lining of small intestine

Lymphatic capillaries

Microscopic, close-ended tubes, extend into interstitial spaces, everywhere w/blood capillaries

Walls have a single layer of squamous epithelial cells → allow interstitial fluid to enter

Lymph

Fluid inside lymphatic capillaries

Lymphatic vessels

Have flaplike valves → prevent backflow of lymph

Lymph nodes

Lymphatic trunks

Drain lymph from vessels

Thoracic duct

Wider and longer collecting duct → receives lymph from:

• Lower limbs

• Abdominal regions

• Left upper limb

• Left side of thorax, head & / neck

Empties into left subdavian vein

Right lymphatic duct

Receives lymph from: the right side of the head/neck + right upper limb + right thorax

Complies into right subclavian vein

Tissue Fluid Formation

tissue fluid originates from blood plasma → composed of water and dissolved substances that leave blood capillaries by filtration

plasma colloid osmotic pressure

osmotic effect of plasma proteins → helps draw fluid back into the capillaries by osmosis

lymph formation

filtration from plasma proteins exceeds reabsorption → net formation of tissue fluid

increases tissue fluid hydrostatic pressure → moves tissue fluid into lymphatic capillaries

lymph function

returns small proteins that the blood capillaries filtered to the BLOODSTREAM

transports foreign particles to lymph nodes

muscular activity

largely influnces the movement of lymph through the lymphatic vessels

• because lymph is usually under low hydrostatic pressure → may not flow easily through lymphatic vessels

• contraction of smooth muscles in the walls of lymphatic trunks

• contraction of skeletal muscles

contraction of skeletal muscles

compresses lymphatic vessels directly, moves lymph inside vessels

• valves in these vessels prevent backflow

contraction of smooth muscle

in the walls of larger lymphatic trunks → contracts rhythmically and compresses the lymph inside → forcing the fluid onward

breathing

creates a relatively low pressure in the thoracic cavity during inhalation

contracting diaphragm increases the pressure in the abdominal cavity

lymph is squeezed out of the abdominal vessels and forced into thoracic vessels, and valves prevent backflow

Edema

When tissue fluid accumulates within interstitial spaces

swelling