Physio 17 Flashcards
What is one of the primary functions of blood flow to the skin?
Determining heat loss from the body
How does blood flow to the skin contribute to maintaining homeostasis?
By controlling body temperature
What is the crucial role of adequate blood plasma delivery to the kidneys?
Allowing the excretion of waste products
Besides waste excretion, what other vital function of the kidneys is dependent on adequate blood plasma flow?
Regulation of body fluid volumes and electrolytes
What does the phrase “extreme degrees of local blood flow control” imply?
Individual organs can tightly adjust their own blood supply.
The control of blood flow to the skin is primarily linked to:
a) Metabolic demand
b) Excretion of waste
c) Thermoregulation
d) Oxygen delivery
Thermoregulation
What are some of the specific needs of the tissues for blood flow?
- Delivery of oxygen to the tissues.
- Delivery of other nutrients, such as glucose, amino acids, and fatty acids.
- Removal of carbon dioxide from the tissues.
- Removal of hydrogen ions from the tissues.
- Maintenance of proper concentrations of other ions in the tissues.
- Transport of various hormones and other substances to the different tissues.
One of the most fundamental principles of circulatory function is the ability of each
tissue to control its own local blood flow in proportion to its _____?
metabolic needs
Thyroid and adrenal glands have blood flows in the range of?
Several hundred ml/min per 100 g of tissue
What is the total blood flow through the liver?
1350 ml/min
The blood flow per 100 g of liver tissue is approximately?
95 ml/min
Chapter 17 highlights an “extremely large blood flow” through which organ?
Kidney
What is the primary reason for the very high blood flow through the kidneys?
To cleanse the blood of waste products
Despite constituting a large percentage of total body mass, inactive muscles have a relatively:
a) Very high total blood flow
b) Very low total blood flow
c) Blood flow similar to the liver
d) Blood flow exceeding that of the kidneys
Very low total blood flow
What is the blood flow per 100 g of inactive muscle tissue?
4 ml/min
During heavy exercise, the metabolic activity of muscles can increase by more than?
60-fold
During heavy exercise, the total blood flow to the body’s muscles can increase up to?
16,000 ml/min
The blood flow per 100 g of muscle tissue during heavy exercise can reach as high as?
80 ml/min
Blood flow of of inactive muscles of the body
750 ml/min
2 phases of local blood flow
- acute control
- long-term control
T/F. Maintaining a very large blood flow through all tissues at all times would be an efficient way for the body to operate
False
True or False: Blood flow to each tissue is generally regulated to match the tissue’s requirements closely.
True
True or False: Blood flow to tissues is usually maintained at a level significantly higher than what is minimally required.
False
True or False: For tissues where oxygen delivery is paramount, blood flow is controlled to be just slightly above the level needed for full oxygenation.
True
True or False: By precisely controlling local blood flow, the workload on the heart is minimized.
True
True or False: Maintaining blood flow at the minimal required level helps prevent both tissue deficiency and unnecessary cardiac workload.
True
Achieved by rapid changes in local
vasodilation or vasoconstriction of the arterioles to provide very rapid maintenance of appropriate local tissue blood flow
Acute control
Slow, controlled changes in flow over a period of days, weeks, or even months that provide better control of the blood flow in to the needs of the tissues.
Long-term control
A result of an increase or decrease in the physical sizes and numbers of actual blood vessels supplying the tissues
Long-term control
Increase in metabolism up to eight times normal increases the blood flow acutely about ___________.
fourfold
One of the most necessary of the metabolic nutrients
Oxygen
Whenever the availability of oxygen to the tissues decreases, such as:
- at high alti tude at the top of a high mountain
- in pneumonia
- carbon monoxide poisoning
- cyanide poisoning
Two basic theories for the regulation of local
blood flow
- vasodilator theory
- oxygen lack theory
Give at least three vasodilator substances
- adenosine
- carbon dioxide
- adenosine phosphate compounds
- histamine
- potassium ions
- hydrogen ions
Believed to diffuse through the tissues to the precapillary sphincters, metarterioles, and arterioles to cause dilation
Vasodilator substances
Vasodilator substances may be released from the tissue in response to?
oxygen deficiency
An increased rate of metabolism in a tissue leads to?
A greater rate of formation of vasodilator substances.
The vasodilator substances, once formed, are believed to act on which blood vessels to cause dilation?
Precapillary sphincters, metarterioles, and arterioles.
The release of vasodilator substances from tissue can be a response to?
Oxygen deficiency
Which two substances are released due to decreased oxygen availability that cause vasodilation?
Adenosine and lactic acid
When blood flow is reduced and cell metabolism continues, the concentration of which substances tends to increase in the tissues?
Vasodilator metabolites like carbon dioxide, lactic acid, and potassium ions.
Many physiologists consider which substance to be an important local vasodilator for controlling local blood flow?
Adenosine.
Minute quantities of adenosine are released from heart muscle cells when?
Coronary blood flow becomes too little.
The release of adenosine in the heart leads to?
Local vasodilation in the heart.
Increased metabolic activity in the heart leads to increased utilization of?
Oxygen
Decreased oxygen concentration in heart muscle cells due to increased metabolism leads to the degradation of?
Adenosine triphosphate
The vasodilator theory primarily explain?
Acute local regulation of blood flow
Also called as oxygen lack theory
Nutrient lack theory
Under special conditions, it has been shown that lack of _____ in the perfusing blood
can cause local tissue vasodilation.
glucose
Vasodilation occurs in the vitamin deficiency disease _____, in which the patient has deficiencies of the vitamin B substances
thiamine, niacin, and riboflavin.
beriberi
Beriberi is associated with deficiencies of which vitamin B substances?
Thiamine, niacin, and riboflavin
In beriberi, the peripheral vascular blood flow often increases by how much?
Twofold to threefold
A deficiency in thiamine, niacin, and riboflavin might lead to diminished?
Smooth muscle contractile ability
T/F. Control of local blood flow is solely dependent on oxygen availability
False
Lack of essential nutrients can potentially influence local blood vessel diameter.
a) True
b) False
True
