Chapter 13 (Part 1) Flashcards
in veins, flow rate ____ in spite of a lack of an ______
increases in spite of a lack of an increase in pressure
why does flow rate increase in veins even though there’s no increase in pressure?
increased vessel internal diameter = lower resistance = increased flow rate
heart contracts = systole or diastole
systole
heart relaxes = systole or diastole
diastole
systole = heart contracts or relaxes
contracts
diastole = heart contracts or relaxes
diastole
what serves as a pressure reservoir between heart beats?
stretch and contraction of blood vessels
what is the role of the pressure reservoir between heart beats?
prevent a large drop in BP when the heart relaxes
how does altitude change blood viscosity?
viscosity increases with altitude; low oxygen means the bone marrow starts to produce RBCs; too many RBCs makes the blood “thicker”
what is the major factor for resistance to blood flow?
vessel radius
what is the significance of going from arteries to arterioles?
diameter decreases = resistance increases = flow rate decreases
which type of vessel provides the greatest resistance to blood flow?
arterioles
why do arterioles provide the greatest resistance to blood flow?
large decrease in diameter that is not compensated by a large increase in arteriole numbers
how to control the MAP? what does MAP stand for?
mean arterial pressure, controlled mainly by changing arteriole diameter
what is myogenic autoregulation?
local control of vascular smooth muscle
