BIO 181 (Capco ASU) Exam 3 (Final Exam) Questions with Verified Solutions

BIO 181 (Capco ASU) Exam 3 (Final Exam) Questions with Verified Solutions Briefly explain why the action potential flows only from the axon hillock to the terminal web. The action potential originates from the axon hillock which initiates the flow of the action potential because of the presence of higher density voltage-gated ion channels. Draw a neuron, and label all the parts as described in lecture. Draw an action potential in the axon of a neuron and indicate which ions flow into the neuron and out of the neuron as the action potential passes at the point where the electrodes are in the cell. Be sure to assign on the Y-axis the mV of each of these areas. This should be as described in my lectures. Explain how insulin and glucagon regulate the balance (i.e, homeostasis) between glycogen and glucose when epinephrine (i.e., adrenalin) is not involved. Glucagon and Insulin work in a negative feedback loop together to keep your blood sugar in a normal range (in a healthy person). Insulin works when your pancreas detects when you have high levels of glucose in your blood stream. Insulin binds to the cells, and some use glucose as energy, and others, like your liver store it as glycogen. Glucagon is the opposite of insulin. After you haven't eaten in a while, your blood glucose levels lower and glucagon signals the cells that have the stored glycogen (liver and muscle cells) to then turn it back into glucose for the other cells to use for energy. Give an example of homeostasis in the kidney. regulating acid-base balance, electrolyte concentrations, extracellular fluid volume, and blood pressure. How do the glial cells (i.e., myelin sheath) speed up the firing of neurons? The cell wraps extensions of a fatty insulating substance (myelin) around the axons of neurons which increase the speed because the action potential jumps from each node of ranvier rather than going down the entire length and firing each Na+K+ pump. In the motor end plate, the event that is the immediate trigger for exocytosis is: Calcium Ions List the 4 types of glial cells and list a phrase to describe their function. - Microglia: Are part of the cellular immune system to protect the brain since the humoral immune system usually cannot cross the BB barrier. - Astrocytes: Contribute to the blood brain barrier - Schwann Cells: myelinates axons of the neurons in the PNS - Oligodendrocytes: Myelinates axons of the neurons of the CNS Once inside the circulatory system __________________ is the molecule that binds oxygen. Hemoglobin One of the problems with the increased surface area of the lungs is that the __________________ could stick to each other causing the lungs to collapse. To get around this the body secretes __________________ into the lungs. alveoli, surfactant Oxygen is distributed throughout the body by: circulatory system T/ F Receptors are made from membrane-bound polyribosomes. True T/F The axon hillock in the pre-synaptic neuron