Veins
Blood Vessels
Vena Cava, Veins and Venules
Fundamentals:
- Vena cava is the largest vein
- Most veins are surrounded by skeletal muscle
- Low pressure means less elastic tissue and amount of smooth muscle
Purpose/Function:
- Carry the blood towards the heart
Anatomy:
- Lumen
- Lined with endothelial cells
- Endothelium
- Tunica intima
- Tunica media
- Tunica externa
- Smooth muscle
- Specialized valves
- allow the blood only in one direction
Specifications/Fundamentals:
- Total cross sectional area 7cm^2
- Blood pressure 0-25 mmHg
- Volume of blood 5-7%
- Velocity 20 cm/s
Concept:
- Regulation
- Under control of the sympathetic nerves
- Gravity, Skeletal Muscle and Valves
- Backflow due to force of gravity
- Veins use valves to prevent backflow
- Skeletal muscle squeezes the veins as the muscles contract forcing the blood up against gravity
Disorders/Diseases:
Terminology:
