(7) Lymphatic System

Question 1

● Consists of lymphatic tissues and vessels
● This system returns protein-rich fluid to the blood circulation that escapes from the blood capillaries into tissue spaces
● Involved in lymphocyte and antibody production, phagocytosis of particulate matter, and movement of fats from the digestive system to the circulation

Answer 1

Lymphatic System

Question 2

are not present in the brain, spinal cord or bone marrow

Answer 2

Lymph vessels

Question 3

• Blind-ended tubes located throughout the body
• More permeable than blood capillaries, they “pick up” the excess interstitial fluid, which is then called lymph

Answer 3

Lymph capillaries

Question 4

the larger vessels formed by the convergence of lymph capillaries

Answer 4

Lymphatic vessels

Question 5

the ovoid or bean-shaped, encapsulated structures located along the course of the medium-sized lymphatic vessels

Answer 5

Lymph nodes

Question 6

located in the lymph nodes, they differentiate into lymphocytes and/or plasma cells

Answer 6

Primitive cells

Question 7

the phagocytic cells lining the walls of the sinuses

Answer 7

Macrophages

Question 8

● Group of lymph nodes draining the same region of the body in all species

Answer 8

Lymphocenters

Question 9

Trunks and ducts drain the lymphocenters back to the general circulation at the so-called?

Answer 9

venous angle

Question 10

is where the ducts or trunks empty into the large veins in the thoracic inlet

Answer 10

venous angle

Question 11

○ represents the parotid lymphocenter
○ It is located under the cranial edge of the parotid gland
○ It drains the dorsal part of the head, including the orbit and parotid gland, then the lymph continues to the retropharyngeal nodes
○ It is palpable in the dog and ox

Answer 11

Parotid lymph node

Question 12

○ represents the mandibular lymphocenter and consists of
nodes located ventral to the angle of the jaw
○ They drain that part of the head not drained by the parotid gland to the medial retropharyngeal node
○ Present in all species, they are palpable in the dog, ox and horse

Answer 12

Mandibular lymph node

Question 13

drains the deeper structures of the head and neck, including the pharynx and larynx

Answer 13

Retropharyngeal lymphocenter

Question 14

the largest lymph node of the head and neck, present in all species

Answer 14

Medial retropharyngeal lymph node

Question 15

usually absent in dog and palpable in the ox

Answer 15

Lateral retropharyngeal lymph node

Question 16

○ represent the superficial cervical lymphocenter
○ Present in all species and palpable in dog, ox and horse
○ Located in front of the shoulder joint under the superficial neck muscles
○ Drain the superficial neck and dorsal thorax along with the proximal part of the forelimb

Answer 16

Superficial cervical lymph nodes

Question 17

the chain of deep lymph nodes (cranial, middle and caudal) along the length of the trachea

Answer 17

Deep cervical lymph nodes

Question 18

○ Traveling along the trachea, draining the
lymph nodes of the head and neck
○ Empty into the thoracic duct on the left
side, the right lymphatic duct, or the
vessels of the thoracic duct

Answer 18

Right and Left Tracheal (Jugular) Trunks

Question 19

dorsal and ventral thoracic lymphocenters represented by the
intercostal and sternal lymph nodes

Answer 19

Parietal

Question 20

mediastinal and bronchial lymphocenters

Answer 20

Visceral

Question 21

consist of the cranial mediastinal lymph nodes in all species

Answer 21

Mediastinal lymphocenters

Question 22

consists of nodes located around the tracheal bifurcation

Answer 22

Bronchial lymphocenters

Question 23

○ constantly present in all species and palpable in dog
○ Located in the axilla, it drains the forelimb and the thoracic wall, including the first three pairs of mammary glands in the dog

Answer 23

Axillary lymph node (part of the axillary lymphocenter)

Question 24

consist of lumbar lymph nodes located along the abdominal
aorta

Answer 24

Lumbar lymphocenters

Question 25

a lymphatic structure found at the caudal end of the thoracic duct that receives lymph draining from the abdominal and pelvic viscera and lower limbs

Answer 25

Cisterna chyli

Question 26

● The major lymphatic vessel drawing the entire body, except the right thoracic limb, right cranial thorax, and the right side of the neck

Answer 26

Thoracic Duct

Question 27

○ masses of unencapsulated lymphoid tissue below mucous membranes (pharyngeal, palatine, and lingual) ○ The major ones protect the entrance to the larynx and esophagus from incoming pathogens

Answer 27

Tonsils

Question 28

diffuse accumulation of lymphatic tissue in the wall of the ileum

Answer 28

Peyer’s patches

Question 29

● The largest lymphoid organ in the body ● Flat, elongated structure interposed in the blood stream located next to the left abdominal wall ● In the fetus, it produces red blood cells ● In the adult, it stores red blood cells that can be squeezed back into circulation when needed ● Produces lymphocytes, stores iron, and destroys worn out red blood cells

Answer 29

Spleen

Question 30

the area where vessels and nerves enter the spleen

Answer 30

Hilus

Question 31

consist of splenic, gastric, hepatic and pancreaticoduodenal lymph nodes that drain associated structures to the cisterna chyli

Answer 31

Celiac lymphocenters

Question 32

consist of jejunal, cecal, and colic lymph nodes

Answer 32

Cranial mesenteric lymphocenters

Question 33

large node located in the root of the mesentery of the dog

Answer 33

Cranial mesenteric lymph nodes

Question 34

represented by the caudal mesenteric lymph nodes draining the descending colon

Answer 34

Caudal mesenteric lymphocenters