Missed Topics - H. nd & WBC#

The hymenolepis species belong to what group?

Cestodes (tapeworms)

What is the nickname for Hymenolepis nana? What is it for Hymenolepis diminuta?

1. H. nana: Dwarf tapeworm

2. H. diminuta: Rat tapeworm

Which species is smaller: H. nana or H. diminuta?

H. nana is smaller

What is the diagnostic form of the Hymenolepis species?

Egg in stool

How can you tell H. nana from H. diminuta?

1. H. nana has 4-8 polar filaments while H. diminuta has none

2. H. nana has a hooked rostellum

How many squares on a hemocytometer do you count for WBC’s? How many for RBC’s? How many for PLT’s?

1. WBC’s: 4 big squares

2. RBC’s: 5 little squares

3. PLT’s: 1 little square

What do you use to hemolyze the whole blood for a WBC count?

1. Ammonium oxalate

2. Acetic acid

3. Hypochloric acid

How much do you dilute the WB before putting it on the hemocytometer?

1:20 to 1:200

What objective do you use to count the WBC’s?

10X

How much error is acceptable for comparing both sides of the hemocytometer?

They should differ no more than 10%

How do you calculate the volume of a square?

Volume = width x length x depth x (# squares counted)

What is typically the volume of a big square? What is typically the volume of a small square?

1. Big square: 0.9 mm³

2. Small square: 0.01 mm³

What are the units of a WBC count?

x 10^9/L

How do you calculate a total WBC count?

[(Total cell #) x (reciprocal of dilution)] / [(# squares counted) x (area/square) x (depth of solution)]