**Core Concept**
Atropine is an anticholinergic medication that inhibits the action of the neurotransmitter acetylcholine at muscarinic receptors. This results in a range of effects on the autonomic nervous system, including increased heart rate, decreased secretions, and altered gut motility.

**Why the Correct Answer is Right**
Atropine causes tachycardia, not bradycardia, by blocking the action of acetylcholine on the sinoatrial (SA) node, which reduces vagal tone and increases sympathetic tone. This is due to the blockade of muscarinic receptors in the SA node, leading to an increase in heart rate. Atropine also increases A-V conduction, as seen in option D, by blocking the action of acetylcholine on the atrioventricular (AV) node, which reduces the refractory period and increases conduction velocity.

**Why Each Wrong Option is Incorrect**
**Option A:** Atropine can actually cause a rise in body temperature due to its anticholinergic effects, which can lead to vasodilation and increased heat loss. However, this is not its primary effect.
**Option B:** Atropine indeed decreases salivary secretion, as well as other secretions such as sweat and tear production, due to its anticholinergic effects on muscarinic receptors in the salivary glands and other exocrine glands.
**Option D:** As mentioned earlier, atropine increases A-V conduction by blocking the action of acetylcholine on the AV node.

**Clinical Pearl / High-Yield Fact**
Atropine's effects on the autonomic nervous system can lead to anticholinergic toxicity, characterized by symptoms such as dry mouth, blurred vision, and tachycardia. It is essential to monitor patients closely for these effects, especially when administering high doses.

**✓ Correct Answer: C. Bradycardia. Bradycardia is not an effect of atropine.**