Immunity and Haematological tissues

Question 1

What is the site of haematopoiesis prior to birth?

Answer 1

Blood islands in yolk sac from week 4 of development. Liver until before birth. Spleen until cartilagenous bone becomes vascularised.

Question 2

What is the yellow marrow?

Answer 2

Deposits of adipose tissue in bone for energy storage.

Question 3

What is the red marrow?

Answer 3

Vascular tissue which is the site of haematopoiesis.

Question 4

Where are immature lymphocyte precursors produced?

Answer 4

In the bone marrow.

Question 5

What are primary lymphoid tissues?

Answer 5

Thymus and Bone marrow where lymphocytes mature and differentiate from immature precursors. It will have either B or T lymphocytes and there is no contact with antigens.

Question 6

What is the composition of the thymus?

Answer 6

Located in the superior mediastinum. It is bilobed with a dark cortical region rich in T lymphocytes and lighter medullary region. It is composed of epithelial, dendritic, mesenchymal cells and endothelial cells. Surrounded by a collagenous capsule which has connective tissue that creates compartmentalisation.

Question 7

What are the secondary lymphoid tissues?

Answer 7

Lymph nodes, spleen, tonsils and GALT and MALT. This is responsible for the acquired immune response involving lymphocytes for pathogen defence.

Question 8

What is the lymphatic system?

Answer 8

A drainage system removing lymph interstitial fluid containing protein, fats, pathogens and lymphocytes to be filtered and returned back to the heart via the subclavian vein.

Question 9

What is the function of the lymphatic system?

Answer 9

Absorption of dietary fat , maintaining fluid levels in the body and pathogen defence.

Question 10

What are the components of the lymphatic system?

Answer 10

Lymph capillaries, lymph nodes and collecting ducts connected to the subclavian vein that returns filtered lymph to the bloodstream.

Question 11

What are lymph capillaries?

Answer 11

Simple endothelial cells which form closed tubes in all tissues excluding the CNS, epidermis and cartilage. They transport fluid toward the collecting duct and respond to hydrostatic pressure of lymph fluid.

Question 12

What are the lymph nodes?

Answer 12

Secondary lymphoid tissue- it is a gland which contains mature lymphocytes to filter lymph of pathogens. Includes MALT and GALT.

Question 13

What is the structure of a lymph node?

Answer 13

Afferent lymphatic vessel carrying lymph into the lymph node. It passes through lymphoid follicles where B cells mature, germinal centre containing memory B cells, T cell area and drains into the medullary sinus where it exits via the efferent lymphatic vessel.

Question 14

What is the germinal centre?

Answer 14

Area in lymph node which contains memory B cells and plasma to fight against reinfection.

Question 15

What is the lymphoid follicle?

Answer 15

Area in lymph node containing B cells.

Question 16

What is the marginal sinus?

Answer 16

Area below the capsule which trap antigens to present to lymphocytes.

Question 17

Where are the superficial lymph nodes in the body?

Answer 17

Superficial lymph nodes follow the superficial veins and drain into the deep lymph nodes.
Cervical lymph nodes which drain the head and neck. Axillary lymph nodes which drain the arms and upper body. Inguinal lymph nodes drain the lower body below the waist.

Question 18

What are the deep lymph nodes?

Answer 18

Deep cervical nodes, Axillary nodes, bronchomediastinal nodes, pre-aortic nodes, para-aortic nodes and deep inguinal nodes

Question 19

Where do the deep lymph nodes drain?

Answer 19

The left or right brachiocephalic veins.

Question 20

Which deep lymph nodes drain into the left brachiocephalic vein?

Answer 20

Left cervical, left axillary, left bronchomediastinal node, pre-aortic node, para-aortic nodes and deep inguinal nodes drain into the left brachiocephalic vein via the thoracic duct.

Question 21

Which deep lymph nodes drain into the right brachiocephalic vein?

Answer 21

Right cervical, right axillary and right bronchomediastinal drain directly into the right brachiocephalic vein.

Question 22

What circulatory systems are involved in immune defence?

Answer 22

Lymphatic circulation and Blood.

Question 23

What is the spleen and function?

Answer 23

Largest secondary lymphoid organ. It is located in the left hypochondrium region between ribs 9-12. It is responsible for removing old or damaged red blood cells and pathogen defence.

Question 24

What is a Howell-Jolly body?

Answer 24

Fragments of nucleated lymphocytes indicative of issues with splenic function.

Question 25

What is an accessory spleen?

Answer 25

Extra-splenic tissue present on the spleen.

Question 26

What is the red pulp and white pulp of the spleen?

Answer 26

Red pulp region contains venous sinuses and is the site of haemolysis.
White pulp region contains lymphocytes and macrophages around arteries to filter blood for pathogen defence.

Question 27

What is splenogamaly an indication of?

Answer 27

Chronic disease such as malaria.

Question 28

What is the role of the follicle in the spleen?

Answer 28

Rich in B lymphocytes.

Question 29

What is the structure of a spleen?

Answer 29

It has a central arteriole where blood enters and a T cell zone, follicle containing B cells and a marginal sinus close to capsule.

Question 30

What is GALT?

Answer 30

Gut-associated lymphoid tissue. It contains a germinal centre, T cell zone and follicle containing B cells.

Question 31

What are the granulocytes?

Answer 31

Erythrocytes, platelets, neutrophils, eosinophils and basophils

Question 32

What is the mononuclear phagocytic system?

Answer 32

Consists of phagocytic cells contained within reticular connective tissues

Question 33

What are the components of mononuclear phagocytic system?

Answer 33

Adipose tissue macrophages in adipose tissues, monocytes in bone marrow, Kuppfer cells in liver and alveolar macrophages in the lungs,

Question 34

what cells are included in the mononuclear phagocytic system

Answer 34

Neutrophils, monocytes and macrophages