1. Perfusion David Taylor dcmt@liv.ac.uk http://www.liv.ac.uk/~dcmt

2.  By the end of this lecture you should be able to describe  The physiological components of the circulatory system  The physiology of tissue perfusion  Oxygen and nutrient delivery  Removal of waste products  General homeostasis of pH and ions Learning Outcomes

3.  The heart, of course, is the pump  Three things are essential to remember.  Pressure from the right of the heart to the lungs is low  Pressure from the left side of the heart is high, but reduces as the blood is distributed through the body.  The same amount of blood leaves the right side of the heart as leaves the left…. Physiological components of the cardiovascular system Chapter 17, p 189 in Preston and Wilson (2013) Chapter 11, p 500 in Naish and Court (2014)

4. Velocity and cross sectional area Cross sectional area cm 2 0 5,000 0 50 Velocity cm/s arteries arterioles capillaries venules veins Chapter 19, p 215 in Preston and Wilson (2013)

5. Systemic Pressures 00 120 arteries arterioles capillaries venules veins Chapter 19, p 215 in Preston and Wilson (2013) 80 40 Systolic pressure Diastolic pressure

6.  In a male 60% of body weight is due to fluid, in a female 55%  2/3 of the fluid is inside cells – intracellular fluid (ICF)  1/3 is extracellular (ECF)  Of the ECF 80% is interstitial fluid  And 20% is plasma  Osmotic pressure and hydrostatic pressure determine the flow between interstitial fluid and plasma Fluids Chapter 3, p 30 in Preston and Wilson (2013) Chapter 2, p 20 in Naish and Court (2014)

7. Perfusion pressure arteriole venule capillary Chapter 19, p 227 in Preston and Wilson (2013) 35mmHg15mmHg Osmotic pressure inside capillary 25mmHg

8. For O 2 and nutrients arteriole venule capillary Chapter 19, p 227 in Preston and Wilson (2013) high low

9. For CO 2 and waste products arteriole venule capillary Chapter 19, p 227 in Preston and Wilson (2013) high lower lowhigher

10.  This topic will unroll as you cover more of the body systems.  Concentration gradients (as mentioned above are of crucial importance), and blood flow and tissue perfusion are needed to ensure them.  But remember that the circulatory system is also a crucial buffer system and if it, or part of it stops working there are local as well as central effects. General Homeostasis

11.  There are others, but the most important system is Buffers HCO 3 - + H + H 2 CO 3 CO 2 + H 2 O Chapter 3, p 35 in Preston and Wilson (2013) Chapter 1, p 11 in Naish and Court (2014)