Question

figure 12.1
using figure 12.1, choose the letter that match the following:

1. pons. 57) ______

figure 14.1
using figure 14.1, choose the letter that match the following:

1. cell body of an ans preganglionic neuron. 58) ______
2. crenation (shrinking) is likely to occur in blood cells immersed in ______.

a) blood plasma b) a hypertonic solution c) an isotonic solution d) a hypotonic solution

1. a good example of a positive feedback mechanism would be ______.

a) regulating glucose levels in the blood b) enhancement of labor contractions
c) blood calcium level regulation d) body temperature regulation

Explanation:

Question 59

Step1: Recall tonicity concepts

Tonicity relates to solute concentration. Hypertonic solution has more solutes than the cell's interior, isotonic has equal, hypotonic has less.

Step2: Analyze crenation

Crenation (shrinking) happens when water leaves the cell. This occurs in a hypertonic solution (more solutes outside, so water moves out via osmosis). Blood plasma is isotonic to blood cells. Hypotonic would cause cell to swell.

Step1: Define feedback mechanisms

Positive feedback amplifies a change; negative feedback reverses it.

Step2: Evaluate options

• A) Glucose regulation: Negative feedback (insulin/glucagon reverse changes).
• B) Labor contractions: Positive feedback (oxytocin increases contractions, amplifying the process).
• C) Blood calcium regulation: Negative feedback (PTH/calcitonin reverse changes).
• D) Body temperature: Negative feedback (shivering/sweating reverse temperature changes).

Answer:

B) a hypertonic solution

Question 60