UCI BioSci D170, Williams Lymph
Reading: Chapter 21
What is the main function of the lymphatic system?
Return excess tissue fluid back to the blood vascular system via lymphatic vessels.
What do lymphatic vessels do? What is lymph? What direction does lymph travel?
Collect excess tissue fluid from loose CT (connective tissue) around capillaries and
return it to the bloodstream; they also return leaked proteins. Lymph is the tissue fluid
once inside the lymphatic vessels.
Describe the order that lymph travels, starting from lymphatic capillaries and ending in the heart.
Lymph flows toward the heart: lymph capillaries drain into lymph nodes, which drain into
lymph trunks, which unite to form lymph ducts, which empty into the veins at the root of
the neck.
Describe the structure and function of lymph capillaries.
Highly permeable vessels located near blood capillaries in the loose areolar CT, that
collect excess tissue fluid. Its walls consist of a single layer of endothelial cells, w/
overlapping adjacent cells that form minivalves. -> An increase in tissue fluid volume
separates minivalves, allowing fluid to enter. Absent in bone, teeth, and bone marrow.
Describe the structure and function of lymphatic vessels.
Have the same tunics as blood vessels, yet are much thinner because the vessels are not
connected to a pumping heart and thus lymph flow under low pressure. At the base of
each valve, the vessel bulges, forming a pocket in which lymph collects -> each vessel
resembles a string of beads.
How is lymph propelled through lymphatic vessels?
● bulging of contracting skeletal muscles, pulsations of nearby arteries.
● tunica media of lymphatic vessels contracts
● limbs and trunk movements
Describe the gross structure and function of lymph nodes. Where are the major ones located in
the body?
Bean-shaped organs situated along the collecting lymphatic vessels; they cleanse the
lymph of pathogens.
● Cervical nodes: along the jugular veins and carotid arteries.
● Axillary nodes: armpit; Inguinal nodes: superior thigh
● (deep)Tracheobronchial nodes: mediastinum.
● Aortic nodes: deep along the abdominal aorta.
● Iliac nodes: deep along the iliac arteries.
Reading: Chapter 21
What is the main function of the lymphatic system?
Return excess tissue fluid back to the blood vascular system via lymphatic vessels.
What do lymphatic vessels do? What is lymph? What direction does lymph travel?
Collect excess tissue fluid from loose CT (connective tissue) around capillaries and
return it to the bloodstream; they also return leaked proteins. Lymph is the tissue fluid
once inside the lymphatic vessels.
Describe the order that lymph travels, starting from lymphatic capillaries and ending in the heart.
Lymph flows toward the heart: lymph capillaries drain into lymph nodes, which drain into
lymph trunks, which unite to form lymph ducts, which empty into the veins at the root of
the neck.
Describe the structure and function of lymph capillaries.
Highly permeable vessels located near blood capillaries in the loose areolar CT, that
collect excess tissue fluid. Its walls consist of a single layer of endothelial cells, w/
overlapping adjacent cells that form minivalves. -> An increase in tissue fluid volume
separates minivalves, allowing fluid to enter. Absent in bone, teeth, and bone marrow.
Describe the structure and function of lymphatic vessels.
Have the same tunics as blood vessels, yet are much thinner because the vessels are not
connected to a pumping heart and thus lymph flow under low pressure. At the base of
each valve, the vessel bulges, forming a pocket in which lymph collects -> each vessel
resembles a string of beads.
How is lymph propelled through lymphatic vessels?
● bulging of contracting skeletal muscles, pulsations of nearby arteries.
● tunica media of lymphatic vessels contracts
● limbs and trunk movements
Describe the gross structure and function of lymph nodes. Where are the major ones located in
the body?
Bean-shaped organs situated along the collecting lymphatic vessels; they cleanse the
lymph of pathogens.
● Cervical nodes: along the jugular veins and carotid arteries.
● Axillary nodes: armpit; Inguinal nodes: superior thigh
● (deep)Tracheobronchial nodes: mediastinum.
● Aortic nodes: deep along the abdominal aorta.
● Iliac nodes: deep along the iliac arteries.
