Ch27 The Lymphatic System

Question 1

Primary transport system

Answer 1

The blood circulatory system

Question 2

The lymphatic system

Answer 2

Secondary transport system
-one way system of dead ending vessels and lymph nodes

Question 3

Function of the lymphatic system

Answer 3

To collect tissue fluid from around cells and return it to the blood

Question 4

What vein does lymph drain back into the blood

Answer 4

Subclavian vein

Question 5

Tissue fluid

Answer 5

Consists of fluid and proteins that are forced out of capillaries (due to high pressure in arteries)

• surrounds all body cells
• similar to plasma, but without red blood cells cells, platelets and larger proteins
• acts as a transport medium that materials entering or exiting cells pass through

Question 6

To prevent swelling?

Answer 6

Oedema
Tissue fluid is drained
-90% re-enters capillaries by osmosis
-10% of lymph enters dead-ending tubes called lymph vessels, which eventually empty into bloodstreams

Question 7

Lymph vessels

Answer 7

Lymph is moved slowly through lymph vessels by the muscular walls of the vessels and by general body movements pressing on the vessels.

Question 8

Valves

Answer 8

Ensure that lymph moves in one direction towards the shoulders

Question 9

Where does lymph drain into the blood stream

Answer 9

At the subclavian veins near the collarbone
-lymph drains into blood at right and left subclavian veins

Question 10

Lymph nodes

Answer 10

Small swellings found along the lymph vessels
-contain large numbers of wbcs and have channels through which lymph flow

Question 11

Lymph nodes fight infection by

Answer 11

1. Filtering bacteria from lymph as it passes through
2. Maturing and storing large numbers of wbcs that kill micro-organisms

Question 12

Glands

Answer 12

Lymph nodes occur in clusters that form glands
-found in areas such as the neck, tonsils, armpits, thymus, groin etc.

Question 13

Oedema

Answer 13

Swollen lymph nodes caused by excess lymph fluid

-when lymph nodes are very active in fighting disease, they may swell : results in swollen glands, indicate the person has an infection

-if lymph vessels become blocked (or if a person is inactive for several hours), swelling (oedema) may result - often ankle, where gravity adds to excess fluid

Question 14

Functions of lymphatic system

Answer 14

1. To collect tissue fluid and return it to the blood
2. Defend the body against infection
   -filtering micro-organisms in lymph nodes
   -maturing and storing lymphocytes which destroy micro organisms directly or by producing antibodies
3. To absorb and transport fats in the digestive system

Question 15

Lymph and fats

Answer 15

-lymph is found in lacteals in the villi of the small intestine i]and is involved in the absorption of fats
-has a milky appearance due to high fat concentration