Cardio - Veins/Lymph Flashcards
(26 cards)
Blood flow from the systemic capillaries enters the ___ and then into the ___. Some exchange of materials occurs in the venules, but ____.
Blood flow from the systemic capillaries enters the venules and then into the systemic veins. Some exchange of materials occurs in the venules, but only a small amount.
The driving force for blood flow from the veins back to the heart is the ____, and is usually on the order of 5-10 mmHg. Resistance to flow is ___ and this driving pressure is ____
The driving force for blood flow from the veins back to the heart is the pressure gradient between the peripheral veins and the right atrium, and is usually on the order of 5-10 mmHg. Resistance to flow is low and this driving pressure is adequate.
The veins also serve a ___ function in that the total volume of the peripheral veins can be altered by ____ acting on vascular smooth muscle in the walls of the vessels to cause _____.
The veins also serve a storage function in that the total volume of the peripheral veins can be altered by sympathetic nerve activity acting on vascular smooth muscle in the walls of the vessels to cause vasoconstriction.
Peripheral veins outside the thorax have valves that …..
Peripheral veins outside the thorax have valves that only permit blood to flow from the periphery toward the heart.
As veins are compressed between____, blood is forced toward the___ but cannot move ____ because of the valves. This action constitutes the ____.
As veins are compressed between contracting skeletal muscles, blood is forced toward the heart but cannot move in the opposite direction because of the valves. This action constitutes the skeletal muscle pump.
During inspiration two things happen.
2.
- The diaphragm descends increasing the intra-abdominal pressure and therefore the peripheral venous pressure.
- the intrathoracic pressure decreases and therefore decreases the pressure in the large veins in the thorax (superior and inferior vena cavae).
increase in “abdominal” venous pressure and the decrease in “thoracic” venous pressure increases the ____ and thus increases _____. This action constitutes the ____ pump.
increase in “abdominal” venous pressure and the decrease in “thoracic” venous pressure increases the pressure gradient and thus increases the amount of blood flowing back to the heart. This action constitutes the respiratory pump.
The most important concept regarding venous return and cardiac output is that they must be…..
The most important concept regarding venous return and cardiac output is that they must be identical except for very brief periods of time.
Lymphatic capillaries are present in virtually all organs and tissues but are distinct from blood vessel capillaries. They have large ____ channels that are permeable to ____, including ____.
Lymphatic capillaries are present in virtually all organs and tissues but are distinct from blood vessel capillaries. They have large water-filled channels that are permeable to all interstitial fluid components, including proteins.
The lymphatic capillaries coalesce into larger and larger vessels ultimately ending in ____ that drain into the subclavian veins in the lower neck. Valves at this junction prevent ____
The lymphatic capillaries coalesce into larger and larger vessels ultimately ending in two large lymphatic ducts that drain into the subclavian veins in the lower neck. Valves at this junction prevent venous blood from entering the lymphatic system.
In the systemic capillaries, the net amount of fluid that is filtered out of the capillaries exceeds _____. This fluid is returned to the cardiovascular system by the _____ along with any ____ that has leaked out of the systemic capillaries.
In the systemic capillaries, the net amount of fluid that is filtered out of the capillaries exceeds the amount that is reabsorbed by about 4 liters per day. This fluid is returned to the cardiovascular system by the lymphatic system along with any protein that has leaked out of the systemic capillaries.
____ that is absorbed from the gastrointestinal system also enters the cardiovascular system by way of the ____.
Fat that is absorbed from the gastrointestinal system also enters the cardiovascular system by way of the lymphatic system.
Smooth muscle in the walls of the lymphatic vessels exhibits ____ and propels the lymph toward the ___. These vessels also have valves that establish ____ flow.
Smooth muscle in the walls of the lymphatic vessels exhibits rhythmical contractions and propels the lymph toward the heart. These vessels also have valves that establish unidirectional flow.
This smooth muscle is activated by ____ and will begin rhythmic contraction when the lymph vessels become ____.
This smooth muscle is activated by stretch and will begin rhythmic contraction when the lymph vessels become distended.
There is some evidence that ____ innervation may also activate this smooth muscle. The ____ mechanism and the _____ also contribute to lymph flow.
There is some evidence that sympathetic innervation may also activate this smooth muscle. The skeletal muscle pump mechanism and the respiratory pump also contribute to lymph flow.
The major cardiovascular variable being regulated is the _____ in the systemic circulation. This ensures _____ to all organs of the body.
The major cardiovascular variable being regulated is the mean arterial pressure in the systemic circulation. This ensures adequate blood flow to all organs of the body.
Mean arterial pressure =
Mean arterial pressure = Cardiac output x Total peripheral resistance MAP=CO x TPR
All changes in mean arterial pressure must be the result of …..
All changes in mean arterial pressure must be the result of changes in cardiac output and/or total peripheral resistance, or both.
The baroreceptor reflex, along with changes in hormonal secretions, provides a means of ….
The baroreceptor reflex, along with changes in hormonal secretions, provides a means of controlling mean arterial pressure over the time span of seconds to hours.
The baroreceptors are ____ located bilaterally in the ____ and in the arch of the ___.
The baroreceptors are specialized collections of nerve endings located bilaterally in the carotid sinuses and in the arch of the aorta.
The baroreceptors are ____ whose rate of firing is directly proportional to the pressures present in the ____ where they are located.
The baroreceptors are stretch receptors whose rate of firing is directly proportional to the pressures present in the large blood vessels where they are located.
Afferent neurons from the baroreceptors travel to the ______
Afferent neurons from the baroreceptors travel to the cardiovascular control centers in the brainstem.
The ____is the primary integrating center for the control of blood pressure. The input to this center comes from the ____ and the output goes to the _____
The medullary cardiovascular center is the primary integrating center for the control of blood pressure. The input to this center comes from the arterial baroreceptors and the output goes to the heart, arterioles, and veins.
Remember that the ____ is adequate for the short-term control of blood pressure.
Remember that the baroreceptor reflex is adequate for the short-term control of blood pressure.
