Control of blood flow

Law of laplace

Tension = pressure * radius

Vascular remodeling occurs as _____

a chronic response to high blood pressure

Autoregulation refers to the _____

ability of a tissue to maintain relatively constant blood flow over a wide range of arterial blood pressures

An increase in tissue metabolic activity results in ____ to meet metabolic demands

active hyperemia (more blood flow)

Oxygen delivery equation:

arterial pO2 * blood flow

_______ also results in increases blood flow

decrease in arteriole O2 saturation

Decrease in arteriole O2 saturation results in _____

decreased O2 delivery to tissues

Capillaries are known as ____

exchange vessels

Increase metabolism means that there is a _____

higher O2 demand

Increase in blood pressure results in ___

increase in tension (vasoconstriction)

Long-term exercise results in _____

increased number of capillaries

Long-term regulation of blood can be done by:

increased tissue vascularity (increase in capillary density)

Myogenic mechanism refers to _____

intrinsic mechanisms to regulate blood flow

There are ______ mechanisms in autoregulation

metabolic and myogenic

Dilation results in _____

more blood flow

Reactive hyperemia is caused by _____

occlusion of an artery for a given time

Number of opened capillaries can be adjusted by _____

precapillary sphincters

Vasoconstriction is caused by _____

rearrangement of smooth muscle and endothelial cells

Each organ can regulate its own _____

resistance vessel or arteriole

Diameter of vessels are controlled by _____

sympathetic activation and inhibition

Temperature regulation is mediated by _____

sympathetic nerves

Normally, arterioles have _____

sympathetic tone (arterial tone)

Skin plays an important role in ______

temperature regulation

Angiogenesis may also be stimulated by ____

tissue injury or exercise

Blood flow increases when ____

tissue metabolism increases

Increase in tissue metabolism results in increase in _____

tissue metabolites (or garbage)

Increase in sympathetic tone results in _____

vasoconstriction

decrease in sympathetic tone results in _____

vasodilation

Endothelial-derived vasoactive paracrines include:

-Nitric oxide -Endothelin

Major stimulant of ____ is _____

-angiogenesis -low pO2

Autoregulation is very good in _____ but not so much _____

-brain and heart -skeletal muscle and GI system

Increase in angiogenesis in diseases is seen in:

-cancer -diabetic retinopathy

Endothelin is released from ______ to ____

-damaged endothelium -prevent excessive bleeding from small arterioles

Increase in temperature results in ____ which causes ______

-decrease in sympathetic activity -vasodilation

Decrease in vascular tone results in _____ which causes ______

-decrease in vascular resistance -increased blood flow

______ also causes:

-decreased oxygen delivery -relaxation of arterioles -relaxation of precapillary sphincters

Increased metabolic activity means:

-demand for O2 -relaxed precapillary sphincters

Increase in number of opened capillaries results in:

-greater surface area for exchange -but decreased diffusion distance

There are ______ when arterial blood pressure is altered, and within minutes, ______

-immediate effects -autoregulatory mechanisms kick in to regulate blood flow

Increase in perfusion pressure results in ______ which results in ______

-immediate increase in flow -vasoconstriction (to decrease flow)

Decrease in blood flow and oxygen delivery results in _____ and _____ which causes ____

-increase in metabolites -decrease in tissue pO2 -vasodilation

Decrease in temperature results in ____ which causes _____

-increase in sympathetic activity -vasoconstriction

Increase in blood flow results in _____

-increase in tissue pO2 -decrease in metabolites

Metabolic activity can be increased by:

-increased CO -exercise

Relaxation of arterioles and precapillary sphincters results in:

-increased blood flow -increased capillary density

Skin has little _____ and ______

-little metabolic activity -little intrinsic mechanisms

In _____ mechanism, Increase in pressure causes ______ which results in _____

-myogenic -stretch of arteriolar muscle wall -contraction of smooth muscle to cause vasoconstriction

Decreased metabolic activity means:

-no need for O2 -contracted precapillary sphincters

In vascular remodeling, with time there will be _____ which results in _____

-no vasoconstriction -hypertrophy of smooth muscle and more ECM (collagen) deposition

Capillary perfusion or blood flow is ___ and it relates to ___

-non-uniform and intermittent -tissue need for oxygen and nutrients

After occlusion of artery for a given time, it causes ______

-occlusion of an artery for a given -reactive hyperemia

Blood flow or _____ to organs is controlled and determined by ______

-perfusion -arterioles

_____ are released from growing endothelial ____ to _____

-platelet derived growth factor -sprout -attract smooth muscle cells and pericytes

Decrease in perfusion pressure (_____) causes _____ which results in ______

-pressure of blood going into organs -decrease in blood flow and oxygen delivery -vasodilation of arterioles

Metabolic mechanism refers to _____ and it is _____

-regulation of blood flow based on metabolic activity of tissues -dominant

Increase tissue metabollites will result in ____

-relaxation of arteriole (vasodilation) -relaxation of precapillary sphincters

During vasoconstriction, there is an increase in _____ which causes _____

-resistance -decrease in flow

Arterioles mostly have ____ in their wall so they can _______

-smooth muscle cells -control their diameter

Endothelin acts on ____ to cause _____

-smooth muscle receptors -increase in intracellular Ca+

Hypertrophy of smooth muscles and increase in ECM deposition will ____ and result in ______

-strengthen and stiffen the wall -increase in cross-sectional area

Diffusion is directly proportional to ____ but inversely proportional to _____

-surface area -diffusion distance

______ are released from _____ to _____

-vascular endothelial growth factor -hypoxic cells -stimulate angiogenesis

Normally, there will be ______ which causes _____

-vasoconstriction in time -no change in cross-sectional area

Nitric oxide is a ____ while Endothelin is a _____

-vasodilator -vasoconstrictor

____ is the regulated variable in myogenic mechanism

Arteriolar wall tension

________ can control blood flow

Endothelial-derived vasoactive paracrines

_____ plays an important role in temperature regulation

Skin