human anatomy and physiology lab 1 blood. background: i. blood is a connective tissue composed of...

Human Anatomy and Physiology

Lab 1

Blood

Background:

I. Blood is a connective tissue composed of formed elements (cells and cell fragments) and intercellular material (plasma)

Blood Sample Centrifuged

Objective 1 Plasma Characteristics

Plasma is the extracellular (intercellular) material of the connective tissue, blood:

Characteristics:

90% H2O

10% solutes:

plasma proteins (albumin, antibodies, clotting proteins)

nutrients (eg, proteins, carbohydrates, lipids, vitamins)

hormones

wastes (eg, urea, uric acid, creatinine)

dissolved gases (CO2, O2)

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 106/mm3

blood

White Blood Cells (WBCs): nucleated cells that provide immunity; there are 5,000 –

9,000/mm3 blood

Platelets (thrombocyte) cell fragments used for hemostasis(stoppage of bleeding); there are250,000 – 400,000/mm3 blood

Red Blood Cells (erythrocytes):

1. Are biconcave discs that lack nuclei and organelles

2. Contain hemoglobin (Hb) which binds to O2

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 monocytesneutrophilseosinophils

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

componentsred/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

- 9-16 m in diameter

- 2-5 nuclear lobes

- pale staining, lavendar granules

Eosinophils:

- 1-4% of the total circulating WBCs

- 10-14 m in diameter

- have a bilobed nucleus

- bright reddish/orange/pink cytoplasmic granules

Basophils:

- 0 – 1% of the total circulating WBCs

- 8-10 m in diameter

- unsegmented or biloed (usually) nucleus

- deep blue/purple cytoplasmic granules

Agranulocytes:

Lymphocyte:

- 20 - 45 % 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

- 4-8 % of the total WBC count

- 14-24 m in diameter

- nucleus is horseshoe shaped or kidney shaped

- abundant blue gray cytoplasm that maycontain 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 Leukocyte Normal % #/100 Cells If Elevated?

Neutrophil 40-70% 40-70 acute infection

Eosinophil 1-4% 1-4 allergic reaction,parasitic infection

Basophil <1% 0-1 ???

Lymphocyte 20-45% 20-45

Monocyte 4-8% 4-8 chronic infection