Human Anatomy and Physiology Lab 1 Blood

Background: I. Blood is a connective tissue composed of formed elements (cells and cellfragments) and intercellular material (plasma)

Blood Sample Centrifuged

Objective 1 Plasma Characteristics Plasma is the extracellular (intercellular) material of the connective tissue, blood: Characteristics: 90% H 2 O 10% solutes: plasma proteins (albumin, antibodies, clotting proteins) nutrients (eg, proteins, carbohydrates, lipids, vitamins) hormones wastes (eg, urea, uric acid, creatinine) dissolved gases (CO 2, O 2 )

Lab Objective 1: In this exercise, you will obtain a sample of sheep plasma and determine its: color clarity pH consistency

Formed Elements:cells and cell fragments Red Blood Cells (RBCs):anucleate cells that carry oxygen; there are 4-6 X 10 6 /mm 3 blood White Blood Cells (WBCs): nucleated cells that provide immunity; there are 5,000 – 9,000/mm 3 blood Platelets (thrombocyte)cell fragments used for hemostasis (stoppage of bleeding); there are 250,000 – 400,000/mm 3 blood

Red Blood Cells (erythrocytes): 1. Are biconcave discs that lack nuclei and organelles 2. Contain hemoglobin (Hb) which binds to O 2 3. They are the most numerous formed element 4. They have a “biconcave” shape 5. Their diameter averages 7.5  m.

There are five types of leukocytes organized into two classes: Agranulocytes: Granulocytes: lymphocytes basophils monocytesneutrophils eosinophils

Platelets (Thrombocytes): 1.Are fragments derived from bone marrow cells (megakaryocytes) 2.They contain granules but no nuclei or organelles 3.They are smaller than RBCs 4.They are used to prevent blood loss (hemostasis)

Objective 2 You will identify each of the formed elements on a prepared blood smear that has been stained with Wright’s stain Wright’s Stain is a mixture of two dyes: 1. Methylene Blue:a basic dye that stains acidic components deep blue/purple 2. Eosin:an acidic dye that stains basic components red/deep pink/orange

Drop of Blood

Different stains can be applied – one popular stain is a differential stain called Wright’s Stain. Wright’s stain is a mixture of eosin and methylene blue. Methylene blue (blue dye) has a positive charge and stains negatively charged substances (acids found in some granules, and DNA and RNA) structures that combine with methylene blue are called basophilic Eosin (red dye) has a negative charge and stains positively charged substances (bases found in some granules, and hemoglobin) structures that combine with eosin blue are called acidophilic Eosin/Methylene Blue Complex stains neutral substances (such as components of some granules) lilac

When blood is smeared onto a slide, dried and stained with Wright’s stain, the individual formed elements (including types of WBC’s) can be distinguished: Erythrocyte Leukocyte Platelet

Granulocytes: Neutrophil:40 – 70% of the circulating WBCs  m in diameter -2-5 nuclear lobes -pale staining, lavendar granules

Eosinophils: -1-4% of the total circulating WBCs  m in diameter -have a bilobed nucleus -bright reddish/orange/pink cytoplasmic granules

Basophils: -0 – 1% of the total circulating WBCs  m in diameter -unsegmented or biloed (usually) nucleus -deep blue/purple cytoplasmic granules

Agranulocytes : Lymphocyte: % of the total WBC count - size ranges from 5  m (small) to 17  m (large); small lymphocytes predominate -nucleus is round or slightly oval; it may be indented - clear blue cytoplasm that may be seen only as a ring around the nucleus Small lymphocyte Large lymphocyte

Monocyte % of the total WBC count  m in diameter -nucleus is horseshoe shaped or kidney shaped -abundant blue gray cytoplasm that may contain vacuoles

Platelets appear as small, granular cell fragments (2-3  m in diameter) that may occur singly or in clumps

Objective 3 A differential white blood cell count is performed to determine the relative percentage of each type of WBC It is used to detect diseases, such as acute infection, chronic infection, allergy, parasitic diseases, anemia, HIV infection, and others

In this activity, you will systematically scan a prepared slide and observe 100 white blood cells -identify each one and record your data to determine the relative percentages of each type of WBC # observed % =X 100 # counted

Each of the leukocytes exists within a range of normal values in peripheral blood. Type of LeukocyteNormal %#/100 CellsIf Elevated? Neutrophil40-70%40-70acute infection Eosinophil1-4%1-4allergic reaction, parasitic infection Basophil<1%0-1??? Lymphocyte20-45%20-45 Monocyte4-8%4-8chronic infection