ATI RN
ATI Pathophysiology Exam 3
1. Which of the following is a cause of edema?
- A. Decreased plasma proteins
- B. Hypotension
- C. Dehydration
- D. Polyuria
Correct answer: A
Rationale: The correct answer is A: Decreased plasma proteins. Edema can be caused by decreased plasma proteins, which reduce the osmotic pressure that keeps fluid in the blood vessels. Hypotension (choice B) is low blood pressure and is not a direct cause of edema. Dehydration (choice C) involves a lack of body fluid, but it is not a direct cause of edema. Polyuria (choice D) is excessive urination and not a direct cause of edema.
2. When a child jumps out of the tub, crying and stating her feet are 'burning,' what pathophysiologic principle is responsible for this response?
- A. Pain receptors (nociceptors) have been activated in response to a thermal stimulus.
- B. The child's skin thermal receptors have undergone adaptation.
- C. The child is exhibiting a psychogenic pain response due to anxiety.
- D. The child is experiencing a conditioned pain response based on previous experiences.
Correct answer: A
Rationale: The child's reaction is due to the activation of nociceptors, which are pain receptors that respond to thermal stimuli. This response is an immediate protective mechanism to prevent tissue damage caused by extreme temperatures. Option B is incorrect because adaptation does not explain the child's immediate and intense response. Option C is incorrect as there is a clear physical stimulus present, ruling out a psychogenic response. Option D is incorrect as the child's response is not based on previous experiences but rather on the current thermal stimulus.
3. 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.
4. In Guillain-Barre syndrome, what pathophysiologic process underlies the deficits that accompany the degeneration of myelin in the peripheral nervous system (PNS)?
- A. The destruction of myelin results in a reduction in Schwann cell production in the client's PNS.
- B. The lack of myelin surrounding nerve cells compromises the axonal transport system.
- C. Without remyelination, the axon will eventually die.
- D. A deficit of myelin makes the client more susceptible to infection by potential pathogens.
Correct answer: C
Rationale: In Guillain-Barre syndrome, the destruction of myelin leads to axonal damage. If remyelination does not occur, the axon will eventually degenerate and die, impacting nerve function. Choice A is incorrect because the destruction of myelin does not affect Schwann cell production. Choice B is incorrect as the lack of myelin directly affects the conduction of nerve impulses, not the axonal transport system. Choice D is incorrect as a deficit of myelin does not predispose the client to infections by potential pathogens.
5. The neurotransmitter GABA mainly functions to trigger inhibitory postsynaptic potentials (IPSPs). Therefore, when explaining this to a group of nursing students, the nurse will state:
- A. It takes at least three chemical substances (amino acids, neuropeptides, and monoamines) to stimulate any activity between the cells.
- B. There is a symbiotic relationship; therefore, the end result will be depolarization of the postsynaptic membrane.
- C. The combination of GABA with a receptor site is inhibitory since it causes the local nerve membrane to become hyperpolarized and less excitable.
- D. The neurotransmitters will interact with cholinergic receptors to bind to acetylcholine in order to produce hypopolarization within the cell.
Correct answer: C
Rationale: When GABA binds with a receptor site, it causes hyperpolarization of the local nerve membrane, making it less excitable. This hyperpolarization leads to inhibition of nerve cell activity. Choice A is incorrect because GABA is a neurotransmitter itself and does not require three chemical substances to stimulate activity between cells. Choice B is incorrect as GABA triggers inhibitory postsynaptic potentials (IPSPs), leading to hyperpolarization, not depolarization, of the postsynaptic membrane. Choice D is also incorrect as it describes a process involving cholinergic receptors and acetylcholine, which is unrelated to GABA's mechanism of action.
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