19-1: Lymphatic vessels

Question 1

What are the two functions of the lymphatic system?

Answer 1

Lymphatic vessels - return excess fluid to blood

Lymphoid organs - fight infection and provide resistance to disease

Question 2

Where does excess fluid come from?

Answer 2

fluid forced out of a capillary bed by hydrostatic and osmotic pressures and not reabsorbed at the venous end

Question 3

What is the function of lymphatic vessels?

Answer 3

to return excess fluid to the cardiovascular system so it can continue functioning

Question 4

lymphatic vessels

Answer 4

system of drainage vessels that collect excess interstitial fluid and return it to the blood stream

Question 5

Fluid in lymphatic vessels is called ___.

Answer 5

Lymph

Question 6

Which way does fluid flow in the lymphatic system?

Answer 6

towards the heart (only one way)

Question 7

What is the organization of lymphatic vessels?

Answer 7

lymphatic capillaries > 
lymphatic collecting vessels > 
lymphatic trunks > 
right and left lymphatic ducts > 
junction of subclavian and internal jugular vein > 
venous circulation

Question 8

right lymphatic duct

Answer 8

drains lymph from right arm and right side of head and chest (right side of body from waist up)

Question 9

left lymphatic duct

Answer 9

drains lymph from left side of body and the right side below waist

Question 10

The flow of lymph is ___.

Answer 10

slow

Question 11

What is the flow of lymph maintained by?

Answer 11

same mechanisms as venous return:
contraction of skeletal muscles
pressure changes in thorax (eg. breathing)
pulsations in nearby arteries
backflow prevented by valves

Question 12

lymphedema

Answer 12

severe, localized swelling caused by anything that prevents the normal return of lymph to blood

Question 13

lymph nodes

Answer 13

filter lymph as it is transported back into the bloodstream (since pathogens and cancer cells can enter lymph easily and spread through the body)

Question 14

What are the two basic functions of the lymph nodes?

Answer 14

filter lymph

activate immune system

Question 15

filter lymph

Answer 15

macrophages in the lymph nodes remove and destroy microbes and debris that entered lymph from infected tissues, preventing them from entering the blood

Question 16

activate immune system

Answer 16

lymphocytes in the nodes monitor the lymph for the presence of antigens (eg. foreign proteins) and mount an immune attack against them

Question 17

What two cells play a role in the lymph nodes?

Answer 17

lymphocytes (immune system) and macrophages (filtering debris)

Question 18

Lymph enters the nodes through __ vessels and leaves through ___ vessels.

Answer 18

afferent; efferent

Question 19

There are fewer ___ vessels, so ___.

Answer 19

efferent; lymph flow slows within node, allowing time for removing pathogens and cleaning

Question 20

swollen glands

Answer 20

lymph nodes may get overwhelmed by the pathogens they are filtering, become inflammed, swollen, and painful