Structure and Function

Question 1

Structures of the lymphatic system

Answer 1

Lymph
Lymphatic vessels
Lymph nodes
Tonsils
Thymus
Spleen
Bone marrow

Question 2

Drainage of Lymph

Question 3

Lymph

Answer 3

• Clear, watery-appearing fluid found in the lymphatic vessels
• Isotonic

Question 4

Interstitial fluid

Answer 4

Fills spaces between cells
Has a lower protein concentration

Question 5

Lymphatic capillaries

Answer 5

• Microscopic vessels that are the origin of lymphatic vessels
  Closed at one end
• Wall of each capillary consists of a single layer of flattened endothelial cells

Question 6

Circulation of Lymph

Answer 6

Water and solutes continually filter out of capillary blood into the interstitial

Question 7

Lymphokinesis

Answer 7

The movement of lymph

Question 8

Lymph nodes

Answer 8

Oval shaped structures enclosed by a fibrous capsule. Lymph enters a node and then moves slowly though sinuses to drain into an exit vessel

Question 9

Where is the thymus located?

Answer 9

Mediastinum

Question 10

What are the functions of lymph nodes?

Answer 10

Mechanical and biological filtration, haematopoiesis

Question 11

What is the relationship between lymphatic and blood capillary networks?

Answer 11

They lie side by side but are always independent of each other

Question 12

What do lymphatic capillaries merge to form?

Answer 12

Larger lymphatics and the main lymphatic trunks

Question 13

Which direction does lymph move through a system?

Answer 13

I’m the right direction because of the larger number of valves

Question 14

What extends from the capsule toward the center of a lymph node?

Answer 14

Trabeculae

Question 15

What are medullary sinuses of the lymph node lined with?

Answer 15

Reticuloendothelial cells capable of phagocytosis

Question 16

Thymus

Answer 16

Unpaired organ made up of two pyramidal lobes. Shortly after birth, thymus secretes thymosin and other hormones resulting in lymphocytes developing into T cells. Final site of lymphocyte development before birth

Question 17

Where is the Thymus located?

Answer 17

Mediastinum

Question 18

What colour is the thymus in childhood?

Answer 18

Pinkish grey

Question 19

How are the lobes of the thymus subdivided?

Answer 19

Lobes of the thymus are subdivided into small lobules by connective tissue septa

Question 20

Thymus point 2

Question 21

Mechanical filtration

Answer 21

Stops particles from progressing further in the body

Question 22

Biological filtration

Answer 22

Processes of cells. Phagocytosis destroys and removes particles

Question 23

Haematopoiesis as a function of lymph nodes

Answer 23

Lymphoid tissue is the site of the final stages of B and T cell maturation

Question 24

Tonsils

Answer 24

Protect against bacteria that may invade tissues around the nasal and oral cavities

Question 25

Where are the tubal tonsils located?

Answer 25

Near the openings of the auditory (eustachian) tubes

Question 26

Pharyngeal tonsils location

Answer 26

Near the posterior opening of the nasal cavity

Question 27

Where are the palatine tonsils located

Answer 27

On each side of the throat

Question 28

Where is the lingual tonsil located

Answer 28

Near the base of the tongue

Question 29

Where is the spleen located?

Answer 29

Upper left quadrant of the abdomen

Question 30

What is the spleen surrounded by?

Answer 30

A fibrous capsule

Question 31

Spleen functions

Answer 31

Defence, tissue repair, haematopoiesis, blood reservoir, RBC and platelet destruction

Question 32

Red pulp (spleen)

Answer 32

A network of fine reticular fibres submerged in blood that comes from nearby arterioles

Question 33

White pulp (spleen)

Answer 33

Contains dense masses of developing lymphocytes

Question 34

Each day, what percentage of proteins leak out of the capillaries into the interstitial fluid?

Answer 34

50%

Question 35

Functions of the lymphatic system

Answer 35

Maintains fluid balance in the internal environment. Lymph vessels act as “drains” to collect excess tissue fluid and return it to venous blood. Returns certain substances to the general circulation

Question 36

What is interstitial fluid absorbed/reabsorbed by?

Answer 36

Interstitial fluid is absorbed by tissue cells or reabsorbed by the blood Oedema (fluid retention) may lead to tissue destruction