Q: While walking in the woods a teenager came across an enticing plant full of berry-like truit. Upon consuming some of the fruit the teenager began to quickly fill unwell, his heart started beating very fast and his pupils dilated causing blurry vision. Based on these symptoms you suspect the berries may have contain a toxin that: A. Blocked the effect of Ach at muscarinic receptors B. Blocked the effect of NE released by preganglionic nerve fiber C. Blocked the effect of NE at sinoatrial node D. Blocked the effect of Ach at nicotinic receptors

Visit this site (http://openstaxcollege.org/l/neurolab) to see a virtual neurophysiology lab, and to observe electrophysiological processes in the nervous system, where scientists directly measure the electrical signals produced by neurons. Often, the action potentials occur so rapidly that watching a screen to see them occur is not helpful. A speaker is powered by the signals recorded from a neuron and it pops each time the neuron fires an action potential. These action potentials are firing so fast that it sounds like static on the radio. Electrophysiologists can recognize the patterns within that static to understand what is happening. Why is the leech model used for measuring the electrical activity of neurons instead of using humans?

A target effector, such as the heart, receives input from the sympathetic and parasympathetic systems. What is the actual difference between the sympathetic and parasympathetic divisions at the level of those connections (i.e., at the synapse)?

Watch this animation (http://openstaxcollege.org/l/bloodflow1) to see how blood flows to the brain and passes through the circle ofWillis before being distributed through the cerebrum. The circle of Willis is a specialized arrangement of arteries that ensure constant perfusion of the cerebrum even in the event of a blockage of one of the arteries in the circle. The animation shows the normal direction of flow through the circle of Willis to the middle cerebral artery. Where would the blood come from if there were a blockage just posterior to the middle cerebral artery on the left?

Watch this animation (http://openstaxcollege.org/l/CSFflow) that shows the flow of CSF through the brain and spinal cord, and how it originates from the ventricles and then spreads into the space within the meninges, where the fluids then move into the venous sinuses to return to the cardiovascular circulation. What are the structures that produce CSF and where are they found? How are the structures indicated in this animation?

Which of the following is not a target of a sympathetic preganglionic fiber? intennural ganglion collateral ganglion adrenal gland chain ganglion

Figure 35.26 Which of the following statements is false? The parasympathetic pathway is responsible for relaxing the body, while the sympathetic pathway is responsible for preparing for an emergency. Most preganglionic neurons in the sympathetic pathway originate in the spinal cord. Slowing of the heartbeat is a parasympathetic response. Parasympathetic neurons are responsible for releasing norepinephrine on the target organ, while sympathetic neurons are responsible for releasing acetylcholine.

Watch this video (http://openstaxcollege.org/l/3Dmovies) to learn about the side effects of 3-D movies. As discussed in this video, movies that are shot in 3-D can cause motion sickness, which elicits the autonomic symptoms of nausea and sweating. The disconnection between the perceived motion on the screen and the lack of any change in equilibrium stimulates these symptoms. Why do you think sitting close to the screen or right in the middle of the theater makes motion sickness during a 3-D movie worse?

Which kind of ding would have anti-anxiety effects? nicotinic agonist anticholinergic muscarinic agonist blocker

Watch this video (http://openstaxcollege.org/l/basalnuclei1) to learn about the basal nuclei (also known as the basal ganglia), which have two pathways that process information within the cerebrum. As shown in this video, the direct pathway is the shorter pathway through the system that results in increased activity in the cerebral cortex and increased motor activity. The direct pathway is described as resulting in disinhibition of the thalamus. What does disinhibition mean? What are the two neurons doing individually to cause this?