NAU Bio 201 Exam 3 Questions With Correct Solutions, Already Passed!!

action potential - the change in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell. Eppendymal cells - produce cerebrospinal fluid satellite cells - surround neuron cell bodies in PNS Schwann cells - produce myelin in PNS stages of AP - 1. depolarization-->threshold reached, Na+ IN --peak: VG Na+ channels Inactivate arization--> K+ OUT 3. hyperpolarization- K+ closes slowly, extra leaves Astrocytes (CNS) - for blood brain barrier; control external environment of neurons Microglia - Act as phagocytes, eating damaged cells and bacteria, act as the brains immune system Oligodendrocytes - produce myelin in CNS resting membrane potential - -70mV graded potential - a shift in the electrical charge in a tiny area of a neuronHyperpolarization - The movement of the membrane potential of a cell away from rest potential in a more negative direction. inhibits Depolarization - Loss of a state of polarity; loss or reduction of negative membrane potential excites absolute refractory period - time during which another action potential is impossible; Na+ gates still inactive Reletive refractory period - AP can occur once RMP is reached, and into hyperol. Na+ channels are closed, and can open again (Because they have to follow cycle) AP propogation speeds - affected by-diameter of axon, mylenation local anesthetics - prevents Na+ channels from opening--> no AP can be fired multiple sclerosis - myelin sheath destruction. disruptions in nerve impulse conduction ( next VG channel is too far due to detroyed mylin) Excititory Postsynaptic Potential EPSP - sodium ions leak in causing depolarization-->closer to threshold stimulate smooth muscle and slow the heart rate decreas in HR, Rest state ISPS Acytelcholinesterase - breaks down ACh in synapse to prevent hyper stimulation of neuron--Off switch inhibited by nerve gas-->drop in HR, convulsions (PNS too turned on)Botulinum toxin (botox) - Blocks release of Ach at the neuromuscular junction, inhibiting muscle contraction endogynist agonist - naturally occuring chemical that turns on receptors drugs that interact with Nicotinic AChR - nicotine-agonist cuvare- antagonist (SA tree resin)=paralysis alpha-bungaro toxin- antagonist (snake venon)=paralysis