activity 5 - blood and lymphatic tissues

7/27/2019 Activity 5 - Blood and Lymphatic Tissues

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Activity 5

BLOOD AND LYMPHATIC

TISSUESHISTOLOGY LAB.


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ERYTHROCYTE LINEAGE

Before release:

All cytoplasmic organelles

degenerate and extrudes

their nucleus

Fully mature:

Consist of outer plasma

membrane enclosing Hb

and limited enzymes to

maintain the cell. (deformreadily and pass through

capillaries)


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The relative proportion of leucocytes in

normal adult human blood (per mm3) is as

follows:

Basophils- 0.5-1 per cent, 35 to 70/mm3

Eosinophils- 1-3 per cent, or 70 to 21O/mm3

Monocytes- 2-10 per cent, or 140 to 700/mm3

Lymphocytes- 20-45 per cent, or 1400 to

3150/mm3

Neutrophils- 60-75 per cent, or 4200 to

5200/mm3

B E M L N


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Leucocytes / White Blood Cells

Basophil Lymphocyte

B cell / T cell


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Leucocytes Main Products Main Functions

Neutrophil Specific granules and

modified lysosomes

(azurophilic granules)

Phagocytosis of bacteria

Eosinophil Specific granules,

pharmacologically active

substances

Defense against parasitic helminths;

modulation of inflammatory processes

Basophil Specific granules

containing histamine andheparin

Release of histamine and other

inflammation mediators

Monocyte Granules with lysosomal

enzymes

Generation of mononuclear-phagocyte

system cells in tissues; phagocytosis and

digestion of protozoa and virus and

senescent cells

B lymphocyte Immunoglobulins Generation of antibody-producing

terminal cells (plasma cells)

T lymphocyte Substances that kill cells.

Substances that control

the activity of otherleukocytes (interleukins)

Killing of virus-infected cells


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LEUCOCYTIC SERIES

1.Myeloblast

2.Progranulocyte orpromyelocyte

Neutrophil lineage4.Neutrophil myelocyte

5.Young neutrophil

metamyelocyte

6.band neutrophil

metamyelocyte

7.Segmented neutrophil


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LEUCOCYTIC SERIES

1.Myeloblast


Eosinophil lineage8.Eosinophil myelocyte

9.Eosinophil

metamyelocyte

10.Segmented

eosinophil


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LEUCOCYTIC SERIES

1.Myeloblast


Basophil lineage11. Basophil myelocyte

12. Segmented basophil


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LEUCOCYTIC SERIES

1.Myeloblast

Monocyte lineage

13. Monoblast

16. Monocyte

3. Megakaryocyte

PLATELETS FORMATION- Megakaryocyte cytoplasm

fragment to form platelets.


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Lymphoblast

Prolymphocyte

B cell

Pre-T cell

THYMUS

Natural

killer

cell

BONE

MARROW


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Platelets / thrombocytes

nonnucleated, disklike

cell fragments

2 to 4 m in diameter

promote blood clottingand help repair gaps in

the walls of blood

vessels, preventing

loss of blood

Normal platelet count

200,000 to 400,000 per

l of blood.


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LYMPHATIC / LYMPHOID

TISSUES

Primary Lymphoid tissues:

Bone marrow - B cell and Pre-T cell devt.

Thymus - T-cell maturation

Secondary Lymphoid Tissues - Exposure toantigens initiates immune responses in thesecondary lymphoid tissues.

Lymph node SpleenPeyers Patches Tonsils

GALT MALT


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Characteristics of Lymphoid

Organs

Concentration of small lymphocytes, asfound in densely packed lymphoid areas.

The smaller, darker nuclei are seen in the

tissue and are pushed to the rim of thenodule.

The germinal centeris pale because of

the presence of large lymphocytes withlarger, paler nuclei.


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Thymus

Flat, bilobed organsituated above the heartand below the thyroidgland.

It increases in size untilit reaches its peakdevelopment duringadolescence.

Becomes smaller withage.


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Thymus (Infant)T cell Maturation

Notice that the medulla (M) tends to stain lighter than

the cortex (C).


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Thymus (Adult)

The post-pubescent thymus involutes and is characterized by areas

of adipose tissue (A).


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The thymus has no germinal centers like many other

lymphoid tissues

but it does have distinguishing Hassall's corpuscles (arrows)

comprised of multiple layers of epitheloid cells.


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Lymph Node - filters both lymph and blood.

Lymph enters the subcapsular sinuses (SS) and exits the

hilar region whereas blood both enters and exits.


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Subcapsular sinus

Subcapsular sinus lined with macrophages where

antigen processing takes place.


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Lymph first enters the sub-capsular sinus (SS)

and then percolates through various

trabeculae (T) to the medulla.


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Follicles in the darkly stained cortex.

Germinal Center - A mass of activated B cells; site where B cells

proliferate and differentiate into plasma cells.


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Germinal Center


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Once in the medulla, lymph is channeled

through medullary cords (MC) to the hilum.

Medulla less densely populated area; contains some T cells, B

cells and macrophages.


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Medullary sinus with medullary cord.


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Spleen - filters out old and damaged cells

and antigens from the blood.

Spleen - The distinctive red pulp (RP) and white pulp (WP) identify

the spleen.


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Parts of the spleen

Red pulpmakes up more than one-half of the totalvolume;

its function is the destruction of old red blood cells

blood flows from the arterioles into the red pulp and exits

through the splenic veinWhite pulp contains the lymphoid tissue

arrangedaround arterioles in a periarterial lymphaticsheath(PALS)

with lymphoid follicles attached; PALS and lymphoidfollicles are surrounded by a marginal zone


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Spleen white pulp


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References

Junquiera LC, Carneiro J. 2005. BASIC HISTOLOGY :

TEXT AND ATLAS 11th Edition. McGraw-Hills ACCESS

MEDICINE.

The JayDoc HistoWeb

http://www.kumc.edu/instruction/medicine/anatomy/histoweb/

BLUE HISTOLOGY

http://www.lab.anhb.uwa.edu.au/mb140/

activity 5 - blood and lymphatic tissues

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