Chapter 18.7 Anatomy of the Blood and Lymphatic Vessels-Cardiovascular System Flashcards
What do Arteries and Arterioles need to be able to do?
expand with high pressure caused by contraction of heart
What do Arteries and Arterioles contain?
elastic layer and smooth muscle layer
Why do Vasoconstriction and vasodilation need for arteries and arterioles?
to regulate blood flow
What are Arteries and Arterioles controlled by?
ANS
What are veins and venules?
They are Vessels that return blood to heart
Why are walls of veins thinner than arteries?
because blood pressure is lower than that in arteries
What are unidirectional valves that veins have do?
They prevent backward flow of blood
What does skeletal pump do as muscle contract?
they apply pressure to veins that run between them
What does unidirectional valves control
direction of flow
What do one-way valves that veins have do?
They prevent backflow of blood
What are Varicose veins?
veins that have become dilated and twisted because of incompetent (leaky) valves
What percentage of adult go through varicose veins and where are they usually?
About 15% of adults suffer from this condition, mainly in lower limbs
What are Capillaries ?
where oxygen and food molecules are transferred from blood to body’s cells
What are capilaries only composed of?
endothelial cells
How close are most cells in body to capillary?
no more than 100 mm from a capillary
