Lymphatics

Question 1

How do Lymphatic vessels differ from blood vessels?

Answer 1

• Completely different vascular network- Collects extravasated fluid from tissues (whereas blood vessels deliver fluid)- Filter lymph- Return lymph to circulation

Question 2

How are lymphatic vessels similar to blood vessels?

Answer 2

Both blood vessels and lymphatic vessels come from a COMMON embryiologic origin that separates during development, which allows for common, yet distinct pathways.

Question 3

What are the two main functions of the lymphatic system? What are two specifics for each function?

Answer 3

• Maintain homeostasis - Cardiovascular assistance with fluid management - Transportation of fats from small intestine to veins- Immunologic role - Filter particulate matter - Develop and deliver antibodies

Question 4

How does homeostasis impact fluid management?

Answer 4

It is the pathway for fluid return from the interstital tissues back to the vascular system

Question 5

How much fluid per day is returned back to the vascular system via the lymphatic system?

Answer 5

2 liters/day

Question 6

What are lacteals?

Answer 6

Lymphatic vessels found in the intestines that are responsible for the transport of lipids into lymph fluid (aka. chyle)

Question 7

Where do the lymphatic vessels transport fat to?

Answer 7

To the blood via the thoracic duct and sent to the liver for processing

Question 8

What are primary lymph organs?

Answer 8

Red bone marrow Thymus

Question 9

What are secondary lymph organs?

Answer 9

• Lymph nodes- Spleen- Lymphatic Nodules (Pharygeal Tonsils)

Question 10

How are primary valves different than secondary valves?

Answer 10

Primary valves are :- Are on smaller vessels- Have only ONE valve (secondary have two to prevent retrograde)- Have only endothelial cells (secondary have smooth muscle and endothelial cells)

Question 11

Describe the basic outline of the Lymph System

Answer 11

• Thin walled channels of endothelial cells- Join together to form larger vessels- Primary lymph valves have ONE-WAY microvalves- Large vessels collect lymphatics (have endothelium and smooth muscles w/ secondary valves that restrict retrograde)- Nodes - located along the path of the collecting lymphatics- Large lymphatic vessels ultimately drain into left and right subclavian veins

Question 12

What is a lymphagion?

Answer 12

Pre-nodal or “afferent” collecting vessels

Question 13

Where do trunks return the lymph to? via?

Answer 13

Venous system via lymphatic ducts.

Question 14

Describe the superficial Lymph System

Answer 14

Drains the skin (not epidermis), musculoskeletal structures, located in groups near veins and travel through the fascia to the deep system

Question 15

Describe the movement of the lymph flow.

Answer 15

Movement goes from peripheral tissues toward the midline of the body then toward cervicothoracic junction.

Question 16

Describe the Deep Lymph System

Answer 16

Drains the thorax, abdomen, pelvis and perinerium

Question 17

How does interstitial fluid get into the lymph capillary?

Answer 17

Hydrostatic GradientsOncotic gradients (dependent on proteins inside and outside the vessels)Mechanical forces (local arterial pulsations and vasomotion, local alveolar expansions, local musculoskeletal compressions upon lymph vessels, passive motion of extremities)

Question 18

Describe the piston activity of the respiratory diaphragm

Answer 18

Inhalation = Diaphragm descends –> increases pressure in intra-abdominal space causing fluid to flow into the terminal vesselBecause aveolar sacs are expanded, there is external mechanical pressure on surrounding pleural lymph nodes.

Question 19

How much of lymph fluid is derived from abdominopelvic fluids?

Answer 19

50%

Question 20

True or False: Respiratory function holds little or no effect on the efficiency of the lymphatic system

Answer 20

False. Proper respiratory function improves the efficiency of the lymphatic system.

Question 21

What is in Lymph Fluid?

Answer 21

Fatty AcidsFatChyleImmune Cells (WBC, lymphocytes in post-nodal duct, antigen-presenting cells, dendtric cells)

Question 22

What are key properties of Lymph capillaries (terminal lymphatics)?

Answer 22

• Larger than blood capillary- One way permeability (fluid only goes in)- Single layer of non-fenestrated endothelial cells that overlap- Incomplete Basement Membrane- No tight junctions : therefore permeable to large particles and proteins- Lack smooth muscle

Question 23

Describe a Lymphangion.

Answer 23

• Begins at the first bicuspid valve, which marks the beginning of the lymphangion or pre-nodal collecting vessel- Drain superficial capillary network- Transport lymph to regional nodes (via affarent vessels)- Possess smooth muscle layer for intrinsic contractile properties and coordinated flow- Pump like arteries: has a filling phase (7 seconds); contraction phase (1 second) and refractory period (1 second). - 130-150 microns in diameter

Question 24

Does lymphatic fluid enter or exit the lymph capillaries during the expansion phase of the capillaries?

Answer 24

Enter! (Influx)

Question 25

What occurs during the compression phase?

Answer 25

The hydrostatic pressure inside the initial lymph increases, causing microvalves to shut and bicuspid valves to open (flowing lymph fluid into the lymphagion

Question 26

Describe lymph nodes shape, contents, and function.

Answer 26

-Kidney bean shaped- Contents: - B Cells - T cells - other immune cellsDistributed widely in the bodyActs as filters or traps for foreign particles (bacteria, viruses, cancer cells etc)

Question 27

Describe the structure of a lymph node

Answer 27

• Afferent lymph vessels enter through the capsule- The Cortex is a fibrous capsule separated into internal segments with geminal centers and an inner medulla- Efferent lymph vessels exit at the Hilum with the artery and veins.

Question 28

Describe the Cysterna Chyli

Answer 28

It’s a VERY IMPORTANT collecting reservoir located at L2 vertebrae that drains into the thoracic duct. All fluids distal (inferior) to the Cysterna Chyli drain into it

Question 29

True or False: Lymph through the cervical lymph nodes will travel through the Cysterna Chyli to the Thoracic Duct

Answer 29

False; Cervical lymph nodes are superior to the cysterna Chyli, therefore do not pass through the CC to the Thoracic Duct

Question 30

What are the two major Lymphatic ducts? What are general properties of both?

Answer 30

1) Thoracic Duct2) Right Lymphatic DuctProperties include:- thin walled- have smooth muscle- secondary vessels- have organized lymphangions- under sympathetic nervous system control

Question 31

Where is the Thoracic Duct? What does it drain lymph from? Where does empty into?

Answer 31

The Thoracic Duct is located at the level of thoracic vertebra.Drains lymph from: left head, neck arm, arm left thorax (partial left lung) cysterna Chyli (hence also, abdominal, pelvic and LEX)Empties into the LEFT internal jugular and subclavian veins

Question 32

Where does the Lymphatic Duct drain lymph from? Where does it return lymph to?

Answer 32

Drains from: Right upper extremity right side of head, neck and chest right lungDrains to: veins at right subclavian veins

Question 33

What is the rate for the movement of lymph? What does it depend on?

Answer 33

10 mm/secDependent on: - Hydrostatic pressure - interstitial oncotic pressures - Intrinsic contraction of lymphangion smooth muscle - External compressive forces.

Question 34

What is the definition of lymphangion?

Answer 34

The space between bivalve to bivalve.

Question 35

What is edema? What is the cause of Edema?

Answer 35

Edema is the flow of lymph back into the interstitum.This is caused by obstruction that cause swelling of vessels that disrupt cause back flow and the anchoring filaments.

Question 36

What are causes of Flow Disturbance?

Answer 36

Local: Interstitial fluid pressures and ECM strainSystemic: Contraction of lymphangion smooth muscles (intrinsic) and external forces acting on lymph vessels (extrinsic; ex. venous stasis and local cardio pulmonary pressure)

Question 37

What is an intrinisic systemic problem that can cause flow disturbance?

Answer 37

contraction of lymphangion smooth muscles

Question 38

What is an extrinsic systemic problem that can cause flow disturbance?

Answer 38

External forces acting on lymph vessels. local cardiopulmonary pressures and venous stasis

Question 39

What is lymphanopathy and what type of screening is required to see it?

Answer 39

Lymphanopathy are enlarged lymph nodes.Require X-rays to visualize