Lymphatic System

Question 1

What are the functions of the lymphatic system?

Answer 1

To play a role in body defence - lymphatic tissue carries out immune responses. To drain excess tissue fluid and return it to the circulatory system.

Question 2

How is lymph formed?

Answer 2

Some blood at the arterial end of a blood capillary leaves the capillary and moved into spaces between the cells to become tissue fluid (interstitial fluid). At the venous end of the blood capillary, most of the fluid returns to the capillary. Not all tissue which passes out into the tissues drains back into the capillaries. Some continues to bathe the tissues while excess tissue fluid drains back into lymphatic capillaries, this fluid is now called lymph.

Question 3

What are lymphatic capillaries?

Answer 3

They are microscopic closed-ended tubes which form a network in the tissues.

Question 4

What are lymphatic vessels?

Answer 4

They resemble veins in structure but have thinner walls and more valves.

Question 5

What is a lymph node?

Answer 5

They are made up of lymph tissue and are scattered throughout the body and filters the lymph from bacteria and cancer cells. It also produces lymphocytes.

Question 6

What is lymph made of?

Answer 6

Protein, cellular debris, foreign particles, and bacteria in tissue fluid. Lymph closely resembles blood plasma in composition and also contains a large number of lymphocytes.

Question 7

What is the flow of the lymph?

Answer 7

Fluid enters the lymphatic capillaries, the lymph then flows into the lymphatic vessels. At intervals along these vessels, the lymph then enters lymph nodes and is filtered. The vessels then join into major lymphatic ducts which pass the lymph into the venous blood supply.

Question 8

What are the lymph nodes in the jaw?

Answer 8

Submandibular lymph nodes.

Question 9

What lymph node is located in below the ear?

Answer 9

Parotid lymph node.

Question 10

What are the lymph nodes in the jaw?

Answer 10

Retropharyngeal lymph nodes.

Question 11

What is the duct in the trachea called?

Answer 11

Tracheal duct.

Question 12

What lymph node is located below the scapula?

Answer 12

Axillary lymph node.

Question 13

What lymph node is located above the scapula?

Answer 13

Prescapular lymph node.

Question 14

What duct is located near the spine?

Answer 14

Thoracic duct.

Question 15

What lymph node is located into the thigh?

Answer 15

Popliteal lymph node.

Question 16

What are the lymph nodes in the chest?

Answer 16

Brochial lymph nodes.

Question 17

What lymph nodes are located near the pelvis?

Answer 17

Superficial inguinal lymph nodes.

Question 18

What lymph nodes are located in the intestine?

Answer 18

Messentenic lymph nodes.

Question 19

What lymph node is located near the bottom of the spine?

Answer 19

Cisterna chyli.

Question 20

What main factors affect the rate of lymph flow in the lymph vessels?

Answer 20

The rate of formation of lymph, the precence of valves in lymph vessels which prevent the blackflow of lymph, respiratory and muscular movement, gravity in the upper parts of the body.

Question 21

What are the main palpable lymph nodes in the dog?

Answer 21

Submadiblar, Superficual cervical or prescapular, popliteal, superficial inguinal. Also parotid and rettopharyngeal, but they are less papable.

Question 22

If an animal has an infected wound, what signs would be apparent?

Answer 22

Swelling around wound, lymph nodes nearby or all lymph nodes being swollen, pain.

Question 23

What can happen to a lymph node that has bacteria inside?

Answer 23

They create lymphocytes to carry out immune response and if the bacteria travel to the lymph node it will filter it but the lymph node may inflame and this will cause it to swell.

Question 24

Where is lymphatic tissue found?

Answer 24

In lymph nodes that are scattered throughout the body. It can also be found in the spleen, tonsils and the thymus gland.

Question 25

Why is the thymus gland most active in a juvenile animal?

Answer 25

The immune system isn’t quite developed so there needs to be T cells for body defence.

Question 26

Why is there a high amount of lymphatic tissue around the intestine?

Answer 26

To help protect the body from the high amounts of bacteria that are present there.

Question 27

What is the immune response?

Answer 27

It is a collective and coordinated response to the introduction of foreign substances into the body or to cellular changes such as cancer.

Question 28

What immunity is an animal born with?

Answer 28

They are born with both physical and chemical barriers such as intact skin, stomach acids, mucus, body temperature and phagocytic cells.

Question 29

How can an animal get artificial immunity?

Answer 29

From vaccinations. Active vaccines stimulate the body to create its own antigens. Passive vaccines are an injection of ready-made antibodies.

Question 30

What is an antigen?

Answer 30

It is a substance that is capable of activating the immune system and stimulating the activation of antibodies.

Question 31

How can animals naturally acquire immunity?

Answer 31

From direct exposure to the infection which is known as active or from antibodies in the mother’s milk known as passive.