Final answer:
The claim that resistance within a blood vessel is mainly due to friction between the blood and the interior vessel wall is true. Vessel diameter and length are key determinants of resistance; a larger diameter and shorter length equate to less resistance and greater flow, whereas a smaller diameter and greater length increase resistance, reducing flow.
Step-by-step explanation:
The statement that within a blood vessel, resistance is primarily due to friction between the blood and the interior vessel wall is true. Resistance in the circulatory system is a critical factor in blood flow and is largely influenced by the physical characteristics of blood vessels. One of the key factors affecting resistance is the diameter of the vessels. When the diameter increases, there is less surface contact between the blood and the vessel wall leading to lower resistance and higher blood flow. Conversely, a smaller diameter causes more blood to contact the wall, increasing resistance, which thus decreases blood flow.
The length of a vessel also plays a role - as the vessel length increases, resistance also increases, and blood flow decreases. Friction between the blood and the interior walls of the blood vessels is the primary cause of this resistance. Within the vascular system, especially in the arterioles, resistance is quite profound due to their small lumen, despite capillaries being smaller in size. The arterioles' role as resistance vessels explains why they slow blood flow from arteries significantly.