Blood Flashcards
What comprises the liquid formed elements of the blood?
The liquid protion of circulating blood is plasma.
The formed elements of the blood are platelets and cells.
What is formed upon clotting?
Upon clotting, some proteins are removed from plasma and other proteins are released from platelets, forming a new liquid termed serum.
What are the important protein components of plasma?
Important protein components of plasma iclude:
- Albumin
- Diverse α- and β-globulins
- Proteins of the compliment system
- Fibrinogen
All of which are secreted within the liver along with immunoglobulins.
Describe erythrocytes
Erythrocytes (red blood cells) make up the hematocrit portion (~45%) of a blood sample.
Enucleated.
Biconcave discs.
7.5um in diameter.
Filled with hemoglobin for the uptake, transport and release of oxygen.
Normal life span of 120 days.
Describe leukocytes.
Leukocytes (white blood cells) are broadly grouped as:
- Granulocytes (neutrophils, eosinophils, basophils) or
- Agranulocytes (lymphocytes, monocytes).
Describe leukocytes.
All leukocytes become active outside the circulation, specifically leaving the microvasculature in a process involving cytokines, selective adhesion, changes in the endothelium, and transendothelial migration or diapedesis.
Describe granulocytes.
All granulocytes have specialized lysosomes called azurophilic granules and smaller specific granules with protein for various cell specific functions.
Describe neutrophils.
Neutrophils are the most abundant type of leukocyte.
They have polymorphic, multilobed nuclei.
Faint pink cytoplasmic granules that contain many factors for highly efficient phagolysosomal killing and removal of bacteria.
Describe eosinophils
Eosinophils have bilobed nuclei and eosinophilic specific granules containing factors for destruction of helminthic parasites and for modulating inflammation.
Describe basophils
Basophils are the rarest type of circulating leukocyte.
Have irregular bilobed nuclei.
Resemble mast cells with strongly basophilic specific granules contining factros important in allergies and chronic inflammatory conditions, including:
- Histamines
- Heparin
- Chrmokines
- Various hydrolases
Describe lymphocytes
Lymphocytes are agranulocytes with many functions as T- and B- cell subtypes in the immune system.
They range widely in size depending on their activation state.
Have roughly spherical nuclei with little cytoplasm and few organelles.
Describe monocytes
Monocytes are larger agranulocytes with distincly indented or C-shaped nuclei that circulate as precursors of marcophages and other cells of the mononuclear phagocyte system.
Decribe platelets
Platelets are small (2-4um) cell fragments derived from megakaryocytes in bone marrow.
With a:
- Marginal bundle of actin filaments
- Alpha granulesanddelta granules
- An open canalicular system of membranous vesicles
- Rapid degranulation on contact with collagen triggers blood clotting
Describe how a blood smear is put on a slide.
Blood cells are studied in smears prepared by spreading a drop of periferal blood in a thin layer on a microscope slide.
Procedure:
- Disinfection of the skin of the finger tip of the left fourth, or thrid finger (for right handers).
- Puncture into the ball of the fingertip with sterile lancet or single use needle.
- The first drop of blood is wiped off because blood is diluted by tissue fluid.
- The second drop of blood is placed near an end of a glass (microscope) slide and spread using another slide (called ‘spreader’ slide).
Explain the spreading process.
- Spreader slide is moved over the glass slide at an angle of 45 degrees.
- When slide edge touches the blood drop, the blood spreads by capillary action along its edge.
- A thin film of blood is obtained by a smooth quick motion of the spreader slide aross a glass slide.
- The air dried blood smear is fixed and stained.
Blood smears are stained with mixtures of acidic and basic dyes.
- Methylene blue and its oxidation products - methylene violet and azure).
