when educating a client about to undergo a pacemaker insertion the nurse explains the normal phases of cardiac muscle tissue during the repolarization

ATI RN

Pathophysiology Exam 1 Quizlet

1. When educating a client about to undergo a pacemaker insertion, the nurse explains the normal phases of cardiac muscle tissue. During the repolarization phase, the nurse will stress that membranes must be repolarized before they can be re-excited. Within the cell, the nurse understands that:

A. Potassium channels open while sodium channels close, causing repolarization to the resting state.
B. The influx of calcium is the primary stimulus for the repolarization of cardiac tissue.
C. Only the electrical activity within the heart will determine when repolarization occurs.
D. The cell membranes need to stay calm, resulting in muscle tissue becoming refractory.

Correct answer: A

Rationale: During the repolarization phase of cardiac muscle tissue, potassium channels open while sodium channels close. This process is crucial for the cardiac muscle to return to its resting state after depolarization. Potassium moving out of the cell and sodium staying out helps reset the membrane potential and prepare the cell for the next depolarization phase. The influx of calcium is not the primary stimulus for repolarization in cardiac tissue; it is mainly involved in the depolarization phase. While electrical activity within the heart influences repolarization, the specific ion movements described in choice A are what physiologically drive repolarization. Cell membranes need to be in an active state during repolarization, not calm, to facilitate the necessary ion movements for muscle tissue to properly function.

2. What are the major mechanisms of spinal cord injuries?

A. Hypoextension, expansion, hyperflexion
B. Hyperflexion, expansion, hypometabolism
C. Hypermetabolism, compression, hyperextension
D. Hyperextension, hyperflexion, compression

Correct answer: D

Rationale: The correct answer is D. Spinal cord injuries commonly occur due to hyperextension, hyperflexion, and compression. Hyperextension and hyperflexion refer to the excessive bending or stretching of the spinal cord, while compression is the exertion of pressure on the spinal cord. These mechanisms can lead to damage such as contusions, lacerations, and compression of the spinal cord. Choices A, B, and C are incorrect as they do not accurately represent the major mechanisms of spinal cord injuries.

3. A patient with a history of osteoporosis is prescribed raloxifene (Evista). What is the primary therapeutic action of this medication?

A. It stimulates the formation of new bone.
B. It decreases bone resorption and increases bone density.
C. It increases calcium absorption in the intestines.
D. It increases the excretion of calcium through the kidneys.

Correct answer: B

Rationale: The correct answer is B: 'It decreases bone resorption and increases bone density.' Raloxifene, as a selective estrogen receptor modulator (SERM), works by reducing bone resorption (breakdown) and maintaining or increasing bone density. This mechanism helps in preventing further bone loss and can even increase bone mass. Choices A, C, and D are incorrect. Raloxifene does not stimulate the formation of new bone (choice A), increase calcium absorption in the intestines (choice C), or increase the excretion of calcium through the kidneys (choice D).

4. What is the treatment for patients with hemophilia A?

A. Chemotherapy
B. Factor VIII replacement
C. Heparin administration
D. Bone marrow transplant

Correct answer: B

Rationale: The correct treatment for patients with hemophilia A is Factor VIII replacement. Hemophilia A is a genetic disorder where there is a deficiency in clotting factor VIII. Therefore, replacing this factor is crucial in managing and preventing bleeding episodes. Choice A, chemotherapy, is not the correct treatment for hemophilia A. Choice C, heparin administration, is not recommended as it can further increase the risk of bleeding in patients with hemophilia. Choice D, bone marrow transplant, is not a standard treatment for hemophilia A.

5. During the cellular stage of acute inflammation, which type of cells arrive first and in great numbers?

A. Basophils
B. Lymphocytes
C. Neutrophils
D. Platelets

Correct answer: C

Rationale: During the cellular stage of acute inflammation, neutrophils are the first responders. Neutrophils arrive at the site of injury in large numbers to combat pathogens and remove debris. Basophils and lymphocytes are also involved in the inflammatory response, but they are not the first to arrive. Platelets play a role in hemostasis and blood clotting, rather than being the primary cells involved in the initial inflammatory response.