Lymphatic System

Question 1

Lymphatic System (1)

Answer 1

lymphatic vessels collect tissue fluid and blood proteins from loose connective tissue
once tissue fluid is within lymphatic vessels it is termed lymph
an important function of the lymphatic system is to return excess tissue fluid and blood proteins to the blood vascular system

Question 2

Orders of Lymphatic Vessels

Answer 2

lymph capillaries: smallest lymph vessels and the first to receive lymph
lymphatic collecting vessels: with valves, collect from lymph capillaries; lymph nodes are scattered along collection vessels and filter lymph
lymph trunks: collect lymph from collecting vessels
lymph ducts: empty into veins of the neck

Question 3

Lymphatic Capillaries

Answer 3

lymphatic capillaries interface with blood capillaries
receive tissue fluid from connective tissue, increased connective tissue fluid causes mini-valve flaps to open and allow fluid to enter the lymphatic capillaries
high permeability allows entrance of tissue fluid and protein molecules, and bacteria, viruses, and cancer cells

Question 4

Lymphatic Collecting Vessels

Answer 4

accompany blood vessels
composed of the same three tunics as blood vessels (i.e. tunica intima, tunica media, tunica externa)
contain more valves than veins have, helps direct the flow of lymph
lymph propelled by skeletal muscles bulging, nearby arteries pulsing, tunica media of the lymph vessels
lymph flow is not directly aided by heartbeat

Question 5

Lymph Nodes

Answer 5

filters and cleanses the lymph of pathogens
human body contains around 500 lymph nodes
superficial lymph nodes located in cervical, axillary, and inguinal regions
deep nodes are tracheobroncheal, aortic, and iliac lymph nodes

Question 6

Lymph Nodes (Microscopic Anatomy)

Answer 6

fibrous capsule: surrounds lymph nodes
trabeculae: connective tissue strands
outer cortex: B cells
inner cortex: T cells, especially T helper cells
medulla: medullary cords contain T lymphocytes, B lymphocytes, and plasma cells
lymph vessels in relationship to lymph nodes
afferent lymphatic vessels flow into lymph node
efferent lymphatic vessels flow away from lymph node

Question 7

Lymph Trunks

Answer 7

lymphatic collecting vessels converge into five major lymphatic trunks:
jugular trunks: drain lymph from head and neck
subclavian trunks: receive lymph from upper limbs and thoracic wall
bronchomediastinal trunks: collects lmph from thoracic viscera
intestinal trunk: receives chyle from digestive organs
lumbar trunks: receives lymph from lower limbs

Question 8

Lymph Ducts

Answer 8

thoracic duct: drains 3/4ths of body

right lymphatic duct: drains right superior quarter of body

Question 9

Thoracic Duct

Answer 9

drains 3/4ths of body including the left side of the head and trunk and both lower extremities
ascends along vertebral bodies and empties into venous circulation at junction of left internal jugular and left subclavian veins
cisterna chyli is most inferior part of thoracic duct and is located around L1-L2 at the union of lumbar and intestinal trunks

Question 10

Right Lymphatic Duct

Answer 10

the right jugular, subclavian, and bronchomediastinal trunks flow into the right lymphatic duct
empties into venous blood at junction of right internal jugular and subclavian veins
drains right superior quarter of body
some people lack the right lympatic duct

Question 11

Lacteals

Answer 11

specialized lymphatic capillaries
located in the villi of the small intestines
receive digested fats
fatty lymph in lacteals is called chyle
deliver fat to vena cava

Question 12

Lymphatic System (2)

Answer 12

returns excess tissue fluid into the blood
returns leaked proteins into the blood
lymph nodes along lymphatic collecting vessels function as lymph filters and filter pathogens which helps fight infection in their role as lymph organs of the immune system
lacteals are specialized lymph capillaries which transport fat from the intestinal wall into the blood