Blood Vessels Arteries Capillaries Marieb 19 Arterial System
Blood Vessels Arteries Capillaries Marieb: 19
Arterial System Elastic (Conducting) 1 cm-2. 5 cm Muscular (Distributing) 0. 3 mm-1 cm Arterioles 10 um- 0. 3 mm Diameters for lumens
Elastic (Conducting) Arteries Fire Hose Very elastic Conduct blood with little resistance
Compliance/Distensibility Pressure waves Decreases pressure in smaller vessels
Muscular (Distributing) Arteries Carry blood to organs Smallest named arteries Less elastin, more smooth muscle
Arterioles Largest 3 layers Smallest 2 layers Change diameter
Capillaries Smallest vessel Tunica intima
Three Types of Capillaries Continuous Fenestrated Sinusoidal
Continuous Capillaries Endothelial cells Tight junctions Blood Brain Barrier
Fenestrated Capillaries Pores More material in and out of blood SI Kidney Endocrine glands
Sinusoidal Capillaries Very large fenestrated pores Big intercellular clefts Liver Bone marrow
Capillary Beds
Capillary Beds: Closed Terminal Arterioles Metarterioles + Thoroughfare channel Vascular Shunt Postcapillary venule
Capillary Beds: Open Precapillary sphincters True capillaries
Venous System Venules Veins Superior Vena Cava Inferior Vena Cava
Venous Blood Pressure No pulse Very low pressure Blood is pushed back up to the heart
Systemic Venous System Large Lumen Thin walls Less smooth muscle Less elastin Holds ~65% of blood
Venous Valves
Varicose Veins Pressure destroys valves Veins collapse and become deformed
The Muscular Pump Muscle contraction drives blood to heart
The Respiratory Pump
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