Lympathic system

Question 1

What does the lympatic system consist of?

Answer 1

Lymph
Lymph vessels
Lymph nodes
Lymph organs
Lymphoid tissue
Bone marrow

Question 2

What are the 3 functions of the lymphatic system?

Answer 2

Tissue drainage
Immunity
Absorption in the small intestine

Question 3

What happen during tissue drainage?

Answer 3

Fluid carrying substances escapes capillaries into tissue
Most is returned to the bloodstream by capillaries at the venous end
About 3-4l is not and this drains in to the lymphatic system

Question 4

What happens at absoption in the small intestines?

Answer 4

Breakdown products of fat and fat-soluble materials are absorbed into the lymphatic vessels of the villi.
They drain into larger lymphatic vessels and eventually into the blood stream.

Question 5

How is the lymphatic system involved in immunity?

Answer 5

Lymphatic organs are concerned with the production and maturation of lymphocytes.

Question 6

Where are B-lymphocytes produced and matured?

Answer 6

Bone marrow

Question 7

Where are T-lymphocytes matured?

Answer 7

Thymus

Question 8

What is lymph?

Answer 8

Clear, watery fluid with identicial composition to intersitial fluid and simular to plasma but less protien

Question 9

What does lymph do?

Answer 9

Carries particles e.g., cell debris, bacteria that is filtered and destoryed by nodes
Transport plasma proteins back to the blood

Question 10

What are lymph capilaries?

Answer 10

These originate as blind-ended tubes in the interstitial spaces.
Permeable to all interstitial fluid including protein and cell debris.
Capillaries join up to make larger lymph vessels.

Question 11

What are lymph vessels?

Answer 11

Often found running alongside arteries and veins serving the area.
Cup-shaped valves to ensure that lymph flows in a way one system towards the thorax.
Vessels become larger as they join together

Question 12

What drains into the thoratic duct?

Answer 12

Lymph from both legs, the pelvic and abdominal cavities, the left half of the thorax, head and neck and left arm.

Question 13

What side is the thoracic duct?

Answer 13

Left

Question 14

What drains into the right lymphatic duct?

Answer 14

Lymph from the right half of the thorax, head, neck and right arm.

Question 15

Where does lymph from the ducts drain into?

Answer 15

Subclavian veins

Question 16

How is lymph circulated?

Answer 16

Large lymph vessels have the ability to contract
Compression from activity
Changes in thoracic pressure

Question 17

What are lymph nodes?

Answer 17

Oval or bean-shaped organs that lie along the length of lymph vessels.
Lymph drains through a number of nodes before returning to venous circulation.
Packed with immune and defence cells.
4 or 5 afferent lymph vessels may enter the node but there is only one efferent vessel that carries lymph away.
Positioned at strategic positions throughout the body.
Arranged in deep and superficial groups.

Question 18

What are the 2 lymph node functions?

Answer 18

Defence
Maturation and proliferation of lymphocytes

Question 19

What are the tonsils?

Answer 19

Collections of lymphoid tissue located in the back of the mouth and throat to intercept swallowed or inhaled antigens.
Deep pits and clefts to trap bacteria, which are then destroyed by the defence cells in the tonsil.

Question 20

What is the spleen?

Answer 20

Contains reticular and lymphatic tissue.
Largest lymph organ in the body.
Lies in the left hypochondriac region of the abdominal cavity.
Vascular and contains red blood cells, macrophages, lymphocytes and plasma cells.

Question 21

What are the 4 functions of the spleen?

Answer 21

1. Phagocytosis
   Old and abnormal erythrocytes are destroyed in the spleen,
   Other cellular material e.g., leukocytes, platelets and bacteria is phagocytosed here.
2. Storage of blood
   The spleen contains up to 350ml of blood and in response to sympathetic stimulation can rapidly return it to circulation.
3. Immune response
   The spleen contains T and B lymphocytes which are activated by the presence of antigens.
4. Erythropoiesis
   It is important for fetal blood cell production and the spleen can also fulfil this function in adults when needed.

Question 22

What is the thymus gland?

Answer 22

Lies in the upper part of the mediastinum behind the sternum and extends to the root of the next.
It weights more at birth, grows until puberty and then begins to atrophy.

Question 23

What are the functions of the thymus gland?

Answer 23

Lymphocytes that enter develop into T-lymphocytes.
T-lymphocytes that can distinguish self-tissue from foreign tissue

Question 24

What is mucosa-assocated lymphoid tissue?

Answer 24

Collections of lymphoid tissue that are not enclosed in a capsule.
They contain B and T lymphocytes.
However, as they have no lymphatic vessels, they do not filter lymph and are therefore exposed to disease spread by lymph.

Question 25

What is the largest collection of lymphoid tissue called?

Answer 25

Spleen

Question 26

Which duct has the largest proportion of lymphatic drainage?

Answer 26

Thoracic duct

Question 27

Where does excess interstitial fluid drains directly into?

Answer 27

Lymphatic capillaries