Blood IA %%+ COPY XXXXXXXXXXXXXXXX Flashcards Preview

ME2017 Science A > Blood IA %%+ COPY XXXXXXXXXXXXXXXX > Flashcards

Flashcards in Blood IA %%+ COPY XXXXXXXXXXXXXXXX Deck (12):

 List the functions of blood 

1.Carriage of physiologically active compounds



4.Carriage of gas


6.Maintenance of ECF pH


 What is the average circulating volume in a typical adult male 

Average 70kg

5 litres of blood:

–1L in lungs

–3L in systemic venous circulation

–1L in heart and arterial circulation


Name the plasma proteins and describe their functions 

Circulates biologically active molecules 

1) Albumin: create and maintain oncotic pressure; transport insoluble molecules

2)Globulin - Subdivided into a, ß, g globulins: participate in immune system

3) Fibrinogen and other clotting factors:Blood coagulation



Oncotic pressure

  • Oncotic pressure, or colloid osmotic pressure, is a form of osmotic pressure exerted by proteins, notably albumin, in a blood vessel's plasma (blood/liquid) that usually tends to pull water into the circulatory system, especially capillaries

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Fluid movement/forces 

Net movement of fluid between capillary and interstitial space is subject to two forces:

i) Capillary Hydrostatic Pressure (CHP) favours movement of fluid out of capillary (bulging out)

ii)Plasma protein concentration (high) favours movement of fluid into capillary

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Composition of Blood 2

 Erythrocytes (red blood cells)

  • Most abundant blood cell 
  • 120 day lifespan.
  • Highly flexible, biconcave, non-nucleated, diameter 7-8mm.

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Erythropoiesis (Red Blood Cell Formation)

  • Controlled and accelerated by erythropoietin.

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Composition of Blood 3

  • Leukocytes (white blood cells)
  • Nucleated, larger than RBC’s,

  • Involved in defense against pathogens


White Blood Cells

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Leukopoiesis (white blood cell formation)

  • Cytokines are released from endothelial cells, fibroblasts and/or mature white blood cells.
  • Stimulate both mitosis and maturation of leukocyte
  •   Bacterial -  high in  neutrophils

      Viral -  high in lymphocytes



  • Platelets - membrane bound cell fragments . Rarely nucleated, 2-4mm diameter. Formation governed by Thrombopoietin
  • Adhere to damaged vessel walls and exposed connective tissue to mediate blood clotting
  • DO NOT adhere to healthy intact endothelium.

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Definition: How thick/sticky blood is compared to water.

Plasma - x 1.8 thicker than water

Whole blood - x 3-4 thicker than water

Factors that affect flow rate:

  • Temperature: - increase in temp decreases viscosity and vice versa.  1oC changes viscosity by around 2%
  • flow rate: - decreased flow rate increases viscosity and vice versa
  • haemotocrit (ratio of RBC to total blood vol): 50% increase in    haematocrit increases viscosity approx. 100%