13.1 The Blood Vessels

Question 1

describe the aorta

Answer 1

• the largest artery in the human body

- the major systemic artery

Question 2

what are the layers of the arterial walls

Answer 2

inner layer (endothelium) : a connective tissue membrane that has elastic fibers
middle layer: thickest layer and smooth muscles to regular blood flow and blood pressure
outer layer: fiber connective tissues near middle layer

Question 3

what are arterioles

Answer 3

• small arteries (0.5mm)
• when they are relaxed or contracting, it affects blood pressure
• the higher # of contracting, the lower the bp

Question 4

describe capillaries

Answer 4

• one cell thick walls
• this is the site of gas exchange between their thin walls
• o2 and nutrients diffuses out into tissue
• waste and co2 diffuses into capillary
• create capillary beds (networks of capillaries)
• tissue fluid is dependent upon capillary exchange
• after eating, capillaries that serve digestive system OPEN and those that serve muscle CLOSE

Question 5

how do venules form veins

Answer 5

venules drain blood from the capillaries and then join to from a vein

Question 6

what is the difference between walls of a vein and walls of an artery

Answer 6

• same 3 layer tissue

- veins are less smooth and less connective tissue

Question 7

describe arteries, veins , and capillaries with blood

Answer 7

• arteries carry blood away from the heart to capillaries
• capillaries join arterioles to venules
• veins return blood to the heart