7- Lymphatic and immune system

Question 1

3 functions of the lymphatic system

Answer 1

1. drains excess interstitial fluid
2. transports dietary lipids (and lipid-soluble vitamins)
3. carries out immune response

Question 2

4 components of the lymphatic system

Answer 2

1- Lymph

2- Lymphatic vessels

3- Lymphatic organs and tissue

4- Red bone marrow: The site of lymphocyte production.

Question 3

where do lymphatic capillaries exist?

Answer 3

in the tissue spaces between cells.

Question 4

What connects lymph capillaries to lymph nodes?

Answer 4

lymph vessels

Question 5

joined lymph vessels (out of lymph nodes) are called

Answer 5

lymphatic trunks

Question 6

2 main channels between lymph trunks and where lymph drains into venous blood?

Answer 6

the thoracic duct and the right lymphatic duct

Question 7

structure of lymphatic capillaries:

Answer 7

• slightly larger in diameter than blood capillaries
• closed at one end
• overlapping endothelial cells work as one-way valves
• Attach endothelial cells to surrounding tissue and keep tubes from collapsing under outside pressure.
• Are attached to anchoring filaments (which contain elastic fibres).

Question 8

what are lacteals?

Answer 8

specialised lymphatic capillaries in the villus of the small intestine that function to absorb and transport digested fats from the small intestine into the blood.

Question 9

which is the main collecting duct of the lymphatic system and to where does it receive/drain lymph?

Answer 9

the thoracic duct
receives lymph from head, upper left side of body and entire body below ribs
drains Lymph into venous blood via the left subclavian vein

Question 10

the right lymphatic duct receives and drains lymph from/to where?

Answer 10

Receives lymph from the upper right side of the body.

Drains lymph into venous blood via the right subclavian vein.

Question 11

B cells and T cells mature where (respectively)?

Answer 11

B cells continue to mature in the red bone marrow.

Pre-T cells migrate from the red bone marrow and mature in the thymus.

Question 12

where id the thymus gland located?

Answer 12

between the sternum and the aorta

Question 13

describe the structure of the thymus

Answer 13

The thymus is divided into two oval-shaped lobes, which are sectioned off by a capsule and trabeculae. Each lobe has a cortex and a medulla.

Question 14

What is involution?

Answer 14

progressive atrophy of the thymus following puberty

Question 15

functions of the cortex and medulla of the thymus?

Answer 15

Cortex: Responsible for proliferation and maturation of immature T cells (pre-T cells) which have migrated from the red bone marrow.

Medulla: Responsible for the release of mature and immunocompetent T cells into blood to migrate to lymph nodes and other lymph organs.

Question 16

how does the spleen contribute to the lymphatic system?

Answer 16

by filtering blood

Question 17

3 structure in the spleen?

Answer 17

The Hilum: A location on the surface of the spleen that acts as a point of attachment for the gastrosplenic ligament, and the point of insertion for the splenic artery and splenic vein.

Stroma: Connective tissue cells of the spleen that consists of capsule, trabeculae, fibres and fibroblasts.

Parenchyma: Consists of lymphatic follicles and cells that surround the arteries (‘white pulp’) and vascular network (‘red pulp’).

Question 18

what is white and red pulp?

Answer 18

White pulp: A lymphatic tissue (lymphocytes and macrophages) that exists around branches of splenic arteries.

Red pulp: Consists of venous sinuses filled with blood and splenic tissue (splenic cords).

Question 19

function of white pulp?

Answer 19

White pulp: A lymphatic tissue responsible for the performance of B cells, T cells and macrophages, which are involved in immune functions similar to lymph node process.

Question 20

function of red pulp?

Answer 20

Red pulp: Consists of venous sinuses filled with blood and splenic tissue and responsible for the removal of ruptured/worn out RBCs and the storage of platelets.