The lymphatic system

Question 1

functions of the circulatory system

Answer 1

• returns excess fluid that has leaked from capillaries
• filter pathogens
• produce and mature lymphocytes which produce antibodies
• Transport the products of fat digestion via the lacteals

Question 2

what is lymph?

Answer 2

Lymph fluid is similar to plasma but without the larger plasma proteins

fluid that has leaked from capillaries

it contains more lymphocytes than circulating blood

Question 3

Lymphatic system

Answer 3

• made up of lymphatic vessels and lymphoid tissue
• they are found all over the body with the exception of nervous tissue and bone marrow

Question 4

Lymphatic Capillaries

Answer 4

• excess fluid is collected the interstitial space by small lymphatic vessels - the lymphatic capillaries

the capillaries are thin walled, delicate tubes which form a network within the tissues

Question 5

Lymphatic vessels

Answer 5

• lymphatic capillaries then form larger vessels that have a similar structure to veins

they have small valves within them to only allow lymph to flow one way

lymph flow is passive

Question 6

Lymphatic Ducts

Answer 6

• the lymphatic vessels then enter a larger lymphatic duct
• these then drain into the blood vessels leading to the heart and then return circulation

Question 7

Right Lymphatic Duct

Answer 7

drains lymph from the right side of the head, neck, thorax and right forelimb

Question 8

tracheal ducts

Answer 8

drain lymph from the left side of the head and neck

Question 9

Thoracic duct

Answer 9

this is the main lymphatic duct. it collects lymph from the rest of he body

lower portion of the thoracic duct is called the cisterna chyli

Question 10

Thoracic Duct

Answer 10

it receives lymph from
-left side of the upper body
-left forelimb
-abdomen

the thoracic duct then empties into the jugular vein or cranial vena cava

Question 11

Interstitial fluid

Answer 11

odema is caused by an excess of fluid in this compartment

Question 12

where is lymph nodes on the body

Answer 12

neck
underarm
chest
abdomen
groin

Question 13

Lymphatic nodes

Answer 13

• Each node is surrounded by fibrous connective tissue - capsule

nodes are divided into two regions
cortex
medulla

Question 14

cortex and medulla

Answer 14

cortex - contains lymph nodules that produce lymphocytes

medulla - reticular framework containing phagocyte cells

Question 15

Lymphatic tissue

Answer 15

spleen
thymus
tonsils

Question 16

spleen

Answer 16

largest of the lymphoid organs

stores new blood cells

destroys worn out red blood cells

acts as a filter for foreign materials

produces lymphocytes

Question 17

where is the spleen located

Answer 17

located in the cranial abdomen just behind the stomach

Question 18

Thymus

Answer 18

Important in young animals

it is located in the cranial thorax

it is active in late foetal and early postnatal life and is responsible for production of T - lymphocytes

Question 19

Tonsils

Answer 19

form a ring of lymphoid tissue around the junction of the pharynx with the oral cavity

they are the first line of defence against microorganisms that enter the mouth physical barrier

Question 20

What 3 layers of immunity does the body have?

Answer 20

Physical barrier - integument, tear production etc

Innate immunity - next stage, once gets past first barrier - immediate WBC response

Acquired immunity

Question 20

the immune system

Answer 20

the bodies defence system to protect against disease by detecting and resisting microbial parasitic or neoplastic invasion

the immune system must distinguish between these and the bodies own healthy cells and tissue

Question 21

Leucocytes

Answer 21

Innate -
Neutrophils
monocytes
eosinophils
Basophils

Acquired
Lymphocytes