General Histology and Histotechnique (1st semester; 2012-2-13)

VASCULAR TISSUE - WBC, RBC, Platelets

Blood - The only liquid connective tissue Why is blood a connective tissue? Features: - 8% blood; 92% other fluid - Can only studied through blood smear - Common to all tissues of the body - Binding site - Preserving the true integrity - It maintains support.

General Functions: 1. Transportation 2. Regulation - Body of heat 3. Protection - Contains fibrinogen Composition of blood: 1. ) Blood plasma a. Water - Watery liquid - 91.5% of the total blood plasma - Absorbs, releases heat, transport b. Proteins - 7% blood plasma - Help maintain water balance between blood and

tissues - Regulates blood volume and protein

1. Albumins - smallest - most numerous plasma protein - liver produces albumin Function: Transport proteins for several steroids hormones and fatty acids 2. Globulins

- Where antibodies (fight viruses…) belong Three classes: α, β, γ α and β – produced by liver Function: Transport iron, lipids & fat soluble vitamin γ – Produced by lymphocytes; contains antibodies for immunity. 3. Fibrinogen

- Produced by liver - Essential role in blood clot. c. Other solutes – 1.5% of plasma

1. Electrolytes 2. Nutrients 3. Gasses 4. Regulatory substances 5. Wastes Ex. Urea, uric acid, ammonia, creatinine, creatine, bilirubin.

2. ) Formed Elements - cells and cell fragments I. RBC Formed elements

General Histology and Histotechnique (1st semester; 2012-2-13)

Granulocyte - with granule - Contain more nucleus

Agranulocyte - Without granules - Contain nucleus

Hemopoiesis - Blood cells are formed

Pleuropotent stem cells - derived from mesenchyme - Capable of differentiation into specific type of cells - Replenish, proliferate, differentiate

Myeloid stem cells - Begin their maturation or development in red bone

marrow and give rise to RBC, platelets, monocyte.

Lymphocyte - Development at red bone marrow but complete it

on lymphatic tissues - B Lymphocytes - T Lymphocytes

Progenitor cells - No longer are capable of replenishing themselves - Committed to giving rise to more specific form

elements of life

CFU – Colony Forming Units

Hemopoietic Growth Factors: - Regulates the differentiation and proliferation of a

particular progenitor cell. 1. Erythropoietin or EPO - Hormone produced by kidney and increases the

number of RBC cell precursor 2. Thrombopoiesis or TPO - Produced by the liver - Stimulates the formation of platelets 3. Cytokines - Small glycoprotein produced by:

a. Red bone marrow cells b. WBC’s c. Macrophages d. Fibroblasts e. Endothelial cells

- Act as a local hormone to maintain normal cell function and stimulates proliferation.

Two important families: a. Colony stimulating factor b. Interleukins

**a & b stimulates WBC formation, RBC, & Platelets.

I. RBC/Erythrocytes - Contain hemoglobin - Consist of proteins:

1. Heme - None-protein pigment - Contains iron that combine with Oxygen molecule

that give red color 2. Globin - Protein - 4 polypeptide chains Key role is to transport Oxygen and Carbon dioxide

II. WBC / Leukocytes 1. Granular (Granulocytes) a. Neutrophil: 60-70% - 2-4 lobes - Presence of granules in cytoplasm - Primary granules – small-round- blue colored - Secondary granules – smaller and colored salmon

pink.

General Histology and Histotechnique (1st semester; 2012-2-13)

b. Eosinophil: 2-4% - Bi-lobes - Large granules that stain bright orange/red

c. Basophil: 0.5-1% - 1 lobe - with Blue granules

2. Agranular (Agranulocytes) a. Lymphocytes: 20-30% - Round, dark with heterochromatin nucleus - Thin layer blue cytoplasm with a lot of ribosome - Occur in bone marrow and thymus

Major Types: (i) B Cells (bursa dependent) - Effective in destroying bacteria and inactivating

their toxins.

(ii) T Cells (Thymus) - Attack viruses, fungi, transplanted cells, cancer cells

and some bacteria. - Responsible for transfusion reaction; allergies are

rejection for transplanted organs.

(iii) Natural Killer Cells - Attack wide variety of infections, microbes, tumor

cells.

b. Monocyte: 3-8% - Oval-kidney shaped nucleus - Lighter stained nucleus - Cytoplasm – light blue - Differentiate to macrophages

General Histology and Histotechnique (1st semester; 2012-2-13)

III. Platelets/Thrombocytes - Platelets are bits of cell broken of larger cells. - Platelets produce tiny fibrinogen fibers to form a

net. This net traps other blood cells to form a blood clot.

- Fragment of megakaryocytic - Cytoplasm – light blue/pink - With granules - Dark blue or purple granules.

Why RBC is Biconcave in shaped? How does it related to its functions? Bone Marrow - Major organ former - Found in the medullar canals of long bones and

cavities of spongy bones. Types: 1. Active or red - Color is due to many RBC’s - Production of blood cells 2. Yellow bone marrow - Predominance of adipose cells Main function:

a. Storage of fat b. Reserve of hematopoietic tissue