145-168 Flashcards
A patient is standing. When measured at the level of the heart, the patient’s systolic blood pressure is 100 mmHg.
What will the systolic pressure be if a measurement is obtained at the level of the patient’s ankle?
What will the systolic pressure be if a measurement is obtained at the level of the patient’s ear?
ankle-level systolic pressure: 195 mmHg
ear-level systolic pressure: 70 mmHg
Assume you obtain measurements of the venous blood pressure from a standing patient. When measured at the level of the heart, the patient’s venous blood pressure is 12 mmHg.
What will the venous pressure be if a measurement is obtained at the level of the patient’s ear?
0 mmHg
What kind of anatomic structure is the diaphragm?
The diaphragm is a large muscle located below the lungs that plays an important role in breathing. When the diaphragm contracts, it flattens and moves downward. When the diaphragm relaxes, it becomes a dome shaped and moves upward.
Name the two body cavities that are separated by the diaphragm.
thorax
abdomen
what effect does the diaphragm have on the thorax and abdomen when we inhale or take in a breath of air?
When we breathe in, the diaphragm contracts and moves downward, resulting in compression of the abdomen. Simultaneously, the thorax expands and is decompressed.
what effect does the diaphragm have on the thorax and abdomen when we exhale or let out a breath of air?
When we breathe out, the diaphragm contracts and moves upward, resulting in compression of the thorax. At the same time, the abdomen expands and is decompressed.
During inspiration, is venous return to the heart from the upper extremities increased or decreased?
increased
During expiration, is venous return to the heart from the upper extremities increased or decreased?
decreased
During inspiration, is venous flow from the lower extremeties increased or decreased?
decreased
During expiration, is venous flow from the lower extremities increased or decreased?
increased
What is energy?
generally defined as having the capacity to perform work
what is an energy gradient?
when the energy at one location is different than the energy at another location, an energy gradient is said to exist.
with regard to hemodynamics, why is an energy gradient important?
In hemodynamics, an energy gradient is important because it is the reason why blood flows from one region to another.
what is friction?
“the act of rubbing”. When two structures rub against each other, heat or thermal energy is created.
with regard to hemodynamics, why is friction important?
In hemodynamics, friction acts to decrease the total energy of blood as it flows through circulation. As blood flows through a vessel, some of the energy is lost as a result of friction.
what is inertial loss?
When the speed of an object changes, there is a loss of energy. This energy loss is called interial loss
with regard to hemodynamics, why is inertia important?
in hemodynamics, energy is lost as blood speeds up and slows down.
what is viscosity? What are its units?
the thickness of a fluid
units of Poise
What is viscous loss?
refers to the loss of fluid energy from internal friction between molecules of the fluid as the slide by each other
with regard to hemodynamics, why is viscous loss important?
in hemodynamics, viscous loss acts to decrease the total energy of blood as it flows through circulation
What happens to the volume of blood in the veins when venous pressure is very low?
What happens to the shape of the cross section of veins when venous pressure is very low?
When venous pressure is very low, the veins are only partially filled with blood (volume is reduced). Consequently, the veins partially collapse and their shape becomes flattened.
