Lymphatic Structure And Organs

Question 1

What are the two main lineages of haematopoietic stem cells, and which cells they give rise to

Answer 1

1. Lymphoid progenitor cells…
   T and B LYMPHocytes, NK cells
2. Myeloid progenitor cells…
   Monocytes, RBCs, Platelets, Granulocytes (neutro, baso, eosino)

Question 2

Lymphocyte (T & B) appearance before and after activation

Answer 2

Before - round nucleus, little cytoplasm, slightly bigger than RBC

After: (different)
Plasma B - lots of cyto huge ER
Cytotoxic T - lots of cyto same ER

Question 3

How to identify specific MALT histologically

Answer 3

Observe overlying epithelium

Question 4

What is the route lymph takes through a lymph node

Answer 4

Afferent vessel
Subcapsular sinus
Trabecular sinus
Medullary sinus
Hilum
Efferent vessel

Question 5

In a lymph node, which cells live in
1 - cortical region
2 - paracortical region
3 - medulla

Answer 5

Cortical = B cell (follicles)
Paracortical = T cells
Medulla = Macrophage AND activated B cells

Question 6

What are the 5 layers of the blood thymic barrier, which separates blood vessel from thymus cortex (epithelioreticular cells)

Answer 6

Capillary endothelium
Endothelium basal LAMINA
perivascular CT SHEATH
Epithelioreticular cell basal LAMINA
Epithelioreticular SHEATH

Question 7

Whats the swirley medullary feature of the thymus called

Answer 7

Hassal’s corpuscle

Question 8

Position of thymus

Answer 8

Superior Mediastinum, anterior to heart

Question 9

Position of spleen

Answer 9

Left hypochondriac region

Question 10

In the spleen, what are the two main functional compartments. Which cells are found and why

Answer 10

White pulp:
1 - PALS periarticular lymphatic sheath consists inner T zone and outer (T&B) zone.
2 - B cell follicles. 1Fol or 2nodule note germ centre
3 - Marginal zone. Contains various cells to mount immune response

Red pulp:
1 - Splenic cords (cellular component) - reticular cells, macrophages, plasma cells.
2 - Sinuses engorge with blood

Red pulp filters blood of toxins and old RBCs before reaching systemic circulation

Question 11

3 main functions of the spleen

Answer 11

1. Immune - filters blood just like lymph nodes filter lymph BLOODBORNE PATHOGENS
2. RBC removal
3. Blood reservoir. Sm muscle constricts in haemorrhage

Question 12

What is the route taken by lymphocytes through a lymph node

Answer 12

Afferent arteriole
High-endothelial venule
Lymphoid tissue
High-endothelial venule
Efferent venule

Question 13

Normal haematocrit

Answer 13

40% varies with age. Males tend to be higher

Question 14

What changes does the thymus undergo from infancy to adulthood

Answer 14

1. Involution - loss of thymocytes and adipocyte infiltration
2. Larger blood vessels enable greater exchange of lymphocytes
3. Increase in the size of thymic corpuscles

Question 15

Morphological appearance of:

1. Neutrophils
2. Eosinophils
3. Monocyte

Answer 15

1. Neutrophils - multi-lobed (most abundant) and granulated
2. Eosinophil - bi-lobed and granulated
3. Monocyte - kidney bean and larger

Question 16

Function and location of megakaryocyte

Answer 16

Produce platelets and typically reside in bone marrow sinusoids

Question 17

Name for too much vs too little:

1. Neutrophils
2. Platelets

Answer 17

1. Neutrophilia/neutropenia

2. Thrombocytosis/thrombocytopenia

Question 18

Structure of Thymus

Answer 18

Bi-lobed organ
CT capsule
Trabeculae/septa - major blood vessels
Cortex - site of T cell maturation
Medulla - dendritic, hassals corpuscles, macrophages, mature T cells
NO AFFERENT LYMPH VESSELS

Question 19

All white pulp regions of the spleen have one

Answer 19

Central arteriole

Question 20

Features of diffuse lymphatic tissues

Answer 20

No CT capsule - therefore not an organ

Located in lamina propria

Question 21

Location of tonsils in waldeyer’s ring
Anterior
Lateral
Posterior

Answer 21

Anterior - lingual tonsil (stratified squamous with adjacent salivary glands)
Lateral - palatine tonsil (stratified squamous)
Posterior - pharyngeal tonsil (pseudostratified ciliated with goblet cells)