Hematology: RBCs and WBCs Flashcards
Characteristics of Blood cells
-Connective tissue
-Transports substances throughout the body & helps to maintain a stable internal environment
Erythrocytes
-Biconcave disks
-Contain 1/3 oxygen carrying hemoglobin
When oxygen combines with hemoglobin
The resulting oxyhemoglobin is bright red
Temperature of blood
38 C
pH of blood
7.35 to 7.45
Average volume of blood
5-6 liters (11 pints)
Amount/body weight of blood
8% of body weight
Composition of blood
-55% liquid portion (serum/plasma)
-45% formed elements
Blood includes
-RBCs
-WBCs
-Platelets
-Plasma
Blood hematocrit
Normally 45% cells and 55% plasma
Plasma
Mixture of:
-Water
-Amino acids
-Proteins
-Carbohydrates
-Lipids
-Vitamins
-Hormones
-Electrolytes
-Cellular wastes
Number of RBCs is a measure of
The blood’s oxygen carrying capacity
Typical RBC count
-Males: 4.6 mill to 6.2 mill cells per mm3
-Females: 4.5 mill to 5.1 mill cells per mm3
Embryo and fetus
RBC production occurs in the yolk sac, liver, and spleen
Adult RBC production
Occurs in the red bone marrow
Average lifespan of RBC
120 days
Total number of RBCs remains…
Relatively constant due to a negative feedback mechanism utilizing the hormone erythropoietin
When is erythropoietin released
Released in response to low oxygen levels detected in the kidneys and liver
Intrinsic factor
Produced by stomach parietal cells; aids vitamin B12 absorption in small intestine
What is needed for hemoglobin synthesis
Iron
Erythropoietin
Hypoxia induces kidneys to increase erythropoietin secretion
What is needed for DNA synthesis
Vitamins B12 and folic acid
Protein
Amino acids = globin
Erythropoiesis
-The nucleus is large in the primitive stages and reduces in size as the cell matures
-Eventually the nucleus is extruded
Normal reticulocyte count in peripheral blood
About 1%; useful indication of erythropoiesis
Each heme consists of…
-1 iron atom surrounded by thousands of atoms of hydrogen, oxygen, nitrogen, carbon, and sulfur
The iron atom provides the
Provides the binding site for the oxygen, thus allowing four atoms of oxygen to bond to each atom of iron
What gives blood its red color
The iron in the heme of the molecule; allows hemoglobin to bind well with oxygen
Each heme group is encased
Encased in a group of amino acids, collectively called the globin portion
Alpha and Beta
Two types of protein chains in each hemoglobin molecule
Each whole hemoglobin protein structure contains
Contains two of each type of protein strand with one heme bound to each strand
Heme can bind with oxygen
It is only in combination with these specific protein groups
