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People You Should Know. Sports Trivia. Flashcards in chapter 15 Deck Loading flashcards Fainting is also known as A infarction. B eclampsia. C reactive hyperemia. D vasovagal syncope. E orthostatic hypotension. Perfusion is A blood flow through an organ. B the connection between capillaries and other vessels. C delivery of oxygen to cells. D the driving force behind blood flow. E movement of blood through a shunt. A blood flow through an organ.
The inner lining of blood vessels is called A endoangium. B basal lamina. C endocardium. D endothelium. E endostatin. Smooth muscle is present in the walls of A muscular arteries only. B arteries only. C veins only. D all vessel types except capillaries.
E all vessel types. The highly branched contractile cells that regulate capillary permeability are called A pericytes. B podocytes. C epitheliocytes. D vascular smooth muscle. E endothelial cells. Differences between arterioles and metarterioles include the fact that arterioles A allow blood to bypass capillary beds. B have an endothelial lining. C have a continuous smooth muscle layer in their walls and allow blood to bypass capillary beds. D have a continuous smooth muscle layer in their walls.
E All of the answers are correct. The only blood vessels whose walls permit exchange between the blood and the surrounding interstitial fluids are the A arterioles. B capillaries. C venules. D arterioles and capillaries. E venules and capillaries. Angiogenesis is A an examination of the arteries and veins. B surgical restructuring of the coronary arteries. C having blood drawn into a tube for tests.
D the growth of new blood vessels. E being able to detect a pulse in arteries. Angiostatin and endostatin may be useful in the treatment of A hypertension. B cancer. C hypotension. E myocardial infarction.
B are the same on both the pulmonary and systemic circuits. C reflect the pressure in the major arteries during ventricular systole and diastole. D exactly match the pressures inside the ventricle during systole and diastole. Which of the following is occurring during systole?
A blood pressure increases B more stress is placed on arterial walls C pulse pressure decreases D blood pressure increases and pulse pressure decreases E blood pressure increases and more stress is placed on arterial walls. E blood pressure increases and more stress is placed on arterial walls. The mean arterial pressure MAP is important because A it forces the practitioner to do math, thus they must pay attention to the values obtained.
B it represents the driving pressure for blood flow and it reflects the difference in time that systole lasts compared to diastole. C it reflects the difference in time that systole lasts compared to diastole.
D it represents the driving pressure for blood flow. Blood flow to a tissue will increase if the A vessels constrict. B level of oxygen at the tissue increases. C pH rises. D level of carbon dioxide at the tissue increases. Blood pressure is determined by A measuring the degree of turbulence in a closed vessel. B measuring the force exerted by blood in a vessel.
C measuring the pressure in the left ventricle. In addition to the baroreceptors are chemoreceptors that monitor levels of oxygen, carbon dioxide, and hydrogen ions pH , and thereby contribute to vascular homeostasis. Chemoreceptors monitoring the blood are located in close proximity to the baroreceptors in the aortic and carotid sinuses.
They signal the cardiovascular center as well as the respiratory centers in the medulla oblongata. Since tissues consume oxygen and produce carbon dioxide and acids as waste products, when the body is more active, oxygen levels fall and carbon dioxide levels rise as cells undergo cellular respiration to meet the energy needs of activities.
This causes more hydrogen ions to be produced, causing the blood pH to drop. When the body is resting, oxygen levels are higher, carbon dioxide levels are lower, more hydrogen is bound, and pH rises. Seek additional content for more detail about pH. The chemoreceptors respond to increasing carbon dioxide and hydrogen ion levels falling pH by stimulating the cardioaccelerator and vasomotor centers, increasing cardiac output and constricting peripheral vessels. The cardioinhibitor centers are suppressed.
With falling carbon dioxide and hydrogen ion levels increasing pH , the cardioinhibitor centers are stimulated, and the cardioaccelerator and vasomotor centers are suppressed, decreasing cardiac output and causing peripheral vasodilation.
In order to maintain adequate supplies of oxygen to the cells and remove waste products such as carbon dioxide, it is essential that the respiratory system respond to changing metabolic demands.
In turn, the cardiovascular system will transport these gases to the lungs for exchange, again in accordance with metabolic demands. This interrelationship of cardiovascular and respiratory control cannot be overemphasized. Other neural mechanisms can also have a significant impact on cardiovascular function. These include the limbic system that links physiological responses to psychological stimuli, as well as generalized sympathetic and parasympathetic stimulation.
Endocrine control over the cardiovascular system involves the catecholamines, epinephrine and norepinephrine, as well as several hormones that interact with the kidneys in the regulation of blood volume.
They increase heart rate and force of contraction, while temporarily constricting blood vessels to organs not essential for flight-or-fight responses and redirecting blood flow to the liver, muscles, and heart. Antidiuretic hormone ADH , also known as vasopressin, is secreted by the cells in the hypothalamus and transported via the hypothalamic-hypophyseal tracts to the posterior pituitary where it is stored until released upon nervous stimulation.
The primary trigger prompting the hypothalamus to release ADH is increasing osmolarity of tissue fluid, usually in response to significant loss of blood volume. ADH signals its target cells in the kidneys to reabsorb more water, thus preventing the loss of additional fluid in the urine.
This will increase overall fluid levels and help restore blood volume and pressure. In addition, ADH constricts peripheral vessels. The renin-angiotensin-aldosterone mechanism has a major effect upon the cardiovascular system. Renin is an enzyme, although because of its importance in the renin-angiotensin-aldosterone pathway, some sources identify it as a hormone.
Specialized cells in the kidneys found in the juxtaglomerular apparatus respond to decreased blood flow by secreting renin into the blood. Renin converts the plasma protein angiotensinogen, which is produced by the liver, into its active form—angiotensin I.
Angiotensin I circulates in the blood and is then converted into angiotensin II in the lungs. This reaction is catalyzed by the enzyme angiotensin-converting enzyme ACE. Angiotensin II is a powerful vasoconstrictor, greatly increasing blood pressure. It also stimulates the release of ADH and aldosterone, a hormone produced by the adrenal cortex. Aldosterone increases the reabsorption of sodium into the blood by the kidneys.
Since water follows sodium, this increases the reabsorption of water. This in turn increases blood volume, raising blood pressure.
Angiotensin II also stimulates the thirst center in the hypothalamus, so an individual will likely consume more fluids, again increasing blood volume and pressure. Figure 3. In the renin-angiotensin-aldosterone mechanism, increasing angiotensin II will stimulate the production of antidiuretic hormone and aldosterone. In addition to renin, the kidneys produce erythropoietin, which stimulates the production of red blood cells, further increasing blood volume. EPO stimulates the production of erythrocytes within the bone marrow.
Erythrocytes are the major formed element of the blood and may contribute 40 percent or more to blood volume, a significant factor of viscosity, resistance, pressure, and flow. In addition, EPO is a vasoconstrictor. Overproduction of EPO or excessive intake of synthetic EPO, often to enhance athletic performance, will increase viscosity, resistance, and pressure, and decrease flow in addition to its contribution as a vasoconstrictor.
Secreted by cells in the atria of the heart, atrial natriuretic hormone ANH also known as atrial natriuretic peptide is secreted when blood volume is high enough to cause extreme stretching of the cardiac cells.
Cells in the ventricle produce a hormone with similar effects, called B-type natriuretic hormone. Natriuretic hormones are antagonists to angiotensin II.
They promote loss of sodium and water from the kidneys, and suppress renin, aldosterone, and ADH production and release. All of these actions promote loss of fluid from the body, so blood volume and blood pressure drop. As the name would suggest, autoregulation mechanisms require neither specialized nervous stimulation nor endocrine control.
Rather, these are local, self-regulatory mechanisms that allow each region of tissue to adjust its blood flow—and thus its perfusion. These local mechanisms include chemical signals and myogenic controls. Chemical signals work at the level of the precapillary sphincters to trigger either constriction or relaxation. As you know, opening a precapillary sphincter allows blood to flow into that particular capillary, whereas constricting a precapillary sphincter temporarily shuts off blood flow to that region.
The factors involved in regulating the precapillary sphincters include the following:. Again, these factors alter tissue perfusion via their effects on the precapillary sphincter mechanism, which regulates blood flow to capillaries. Since the amount of blood is limited, not all capillaries can fill at once, so blood flow is allocated based upon the needs and metabolic state of the tissues as reflected in these parameters.
Bear in mind, however, that dilation and constriction of the arterioles feeding the capillary beds is the primary control mechanism. The myogenic response is a reaction to the stretching of the smooth muscle in the walls of arterioles as changes in blood flow occur through the vessel.
This may be viewed as a largely protective function against dramatic fluctuations in blood pressure and blood flow to maintain homeostasis. If perfusion of an organ is too low ischemia , the tissue will experience low levels of oxygen hypoxia.
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