What does neural changes in blood pressure mean
Why are olfactory neurons called modified bipolar neurons
I agree with Bri that these questions are more appropriate for uni students (probably around 2nd year level), but I'm able to answer them for you cuz I'm doing biomed and have just completed anatomy and physiology units at 2nd year level.
Changes in blood pressure are detected by stretch sensitive neurons located in the carotid sinus and the aortic arch called baroreceptors. In response to low blood pressure, they decrease their rate of action potential generation, which tells your medulla oblongata to do something to increase blood pressure as you need to constantly supply your brain with enough O2 from circulation. Your CNS will decrease CN X (vagus nerve), or parasympathetic activity (remember parasympathetic nervous system = rest and digest = slows heart rate) and increase sympathetic activity to increase the rate and force of contraction in order to raise blood pressure. Sympathetic nerve activity will also cause vasoconstriction because noradrenaline will bind to adrenergic receptors on smooth muscles around arterioles which causes them to contract, in turn increasing total peripheral resistance and mean arterial pressure. Sympathetic activity will result in the release of vasopressin (I think you call it ADH in high school) to conserve blood volume which also helps to keep blood pressure up
As for the olfactory neurons, they're bipolar because they both project outwards towards your nose via the cribiform plate where they encode smells using the thin olfactory fibres, and they also project backwards to carry this info towards the olfactory cortex located in the temporal lobe where it's processed. Note that the olfactory neurons aren't like your typical sensory neurons, the olfactory nerve (CN I) isn't considered part of the peripheral nervous system as they're actually extensions of your cerebrum just like the optic nerve (CN II) and the retina, they even have their own meninges so that's why they're considered "modified"