1. Cardiovascular: Blood Vessels

2. Vessel Wall Tunica interna = inner lining of simple squamous epithelium called endothelium & minimal loose C.T. layer Tunica media = mostly smooth muscle, with significant elastic tissue in the large arteries Tunica externa = outermost layer of loose C.T. including small nerves, small lymphatic vessels, & small blood vessels called the vaso vasorum

3. p 755

4. p 758 Capillaries Continuous capillaries = most common type have endothelial cells joined by tight junctions with small (4 nm) spaces called intercellular clefts (blood-brain barrier = brain capillaries that lack intercellular clefts)

5. p 759 Capillaries Fenestrated capillaries = endothelial cells have many filtration pores (fenestrations) of 20 to 100 nm diameter that allow passage of molecules, even some proteins

6. p759 Capillaries Sinusoids = irregular blood-filled spaces with endothelial cells separated by wide gaps that allow passage of proteins & even blood cells in bone marrow

7. p 761

8. p 763

9. p 764 Peripheral Resistance = Opposition to flow that the blood encounters in vessels away from the heart, primarily friction with vessel walls Resistance Factors 1) Blood Viscosity 2) Vessel Length 3) Vessel Diameter resistance = 1/diameter 4

10. Blood Flow Blood flow = volume of blood that passes through a vessel in a given time (ml / min) FLOW = PRESSURE RESISTANCE

11. p 768

12. Blood Velocity Blood velocity = distance blood flows in a given time Blood velocity is inversely related to TOTAL cross-sectional area of blood vessels cross-sectional area average velocity Aorta 3 – 5 cm 2 40 cm / sec Capillaries 4500 – 6000 cm 2 <0.1 cm / sec

14. p 757

16. p 769 Steroid hormones, H 2 O, O 2, & CO 2 thru membranes Glucose & ions thru membrane channels, pores, or intercellular clefts Larger molecules, like proteins, usually blocked Fatty acids, albumin, & some hormones, like insulin, move by transcytosis (pinocytosis + exocytosis)

17. Filtration = movement of fluid out of a blood capillary Reabsorption = movement of a fluid into a blood capillary Hydrostatic Pressure = force exerted by a fluid against the walls of its container, for example blood pressure Colloid Osmotic Pressure (COP) = osmotic pressure due to dissolved proteins Net Filtration Pressure (NFP) = filtration pressures minus reabsorption pressures

18. p 770

20. p 773 Venous Return Milking or skeletal muscle pump Thoracic or respiratory pump

21. p 766 Baroreflex

22. Chemoreflex