Intro to Blood Flashcards
What are the functions of blood ?
- transport
- regulation of pH, osmosis, body temp
- maintenance of homeostasis
Define Hematocrit
the ratio of the volume of red blood cells to the total volume of bold
(packed cell volume)
What are the main components of blood ?
- Plasma - 55%
- Erythrocytes - 45% (formed elements)
- Buffy coat = <1% ( formed elements)
What are the 3 major categories of plasma proteins ?
- albumins - smallest and most abundant
- globulins
- fibrinogen
Describe albumins
- most abundant - 3.5 - 5.0 g/dL blood
- contributes to viscosity & osmolarity
- influences blood pressure, flow and fluid balance
Describe Globulins
- antibodies
- 1.0 -1.5 g/dL blood
- provide immune system function
- alpha, beta and gamme globulins
Describe Fibrinogen
- 0.2-0.45 g/dL blood
- precursors of fibrin threads that help form blood clots
What are some functions of plasma proteins ?
- blood viscosity
- provide 1/6th of the total buffering power of the blood
- transport substances circulating in the blood
- essential for blood clotting mechanisms
What are some of the sub types of granulocytes ?
- neutrophils
- eosinophils
- basophils
What are the sub-types of granulocytes ?
- lymphocytes
- monocytes
What’s another word for platelets ?
thrombocytes
What is haematopoiesis stimulated by?
erythropoietin, thrombopoietin & colony-stimulating factors
How are erythrocytes formed ?
- haemotopoietic stem cells
- committed stem cells
- early erythroblast
- late erythroblast
- normoblast
- reticulocyte
- erythrocyte
Describe the structure of haemoglobin
- each Hb molecule consists of 4 protein chains (globins) and 4 heme groups
Describe heme groups
non-protein moeity that binds oxygen to ferrous ion (Fe2+) at its centre
Describe Globins
- 2 alpha & 2 beta chains
- 5% carbon dioxide in blood is bound to global moiety
What is the haemoglobin concentration of whole blood?
females = 12-16 g/dL
males = 13-18 g/dL
What is the red blood cell count in men and women?
men = 4.6-6.2 million/uL
women = 4.2-5.4 million/uL
Why are RBC counts lower in women ?
- androgens stimulate RBC production
- women have periodic menstrual loss
Define Erythropoiesis
production of red blood cells
Describe the negative feedback control involved in erythrocyte homeostasis
- drop in RBC count causes kidney hypoxemia
- kidney production of erythropoietin stimulates bone marrow
- RBC count increases in 3/4 days