BIOL 1107 UCONN ECE Biology 1107 Final Exam Questions and Answers Review 2024

BIOL 1107 UCONN ECE Biology 1107 Final Exam Questions and Answers Review 2024 BIO FINAL EXAM CHAPTER 46  What happens during an action potential with regard to ions? o Sodium ions move into the cell and potassium ions move out of the cell o Rapid change in membrane potential  Neurons in a cluster is called o Ganglia … A gang is a cluster of people  Types of Neurons in the Nervous system o Sensory receptors decode data from environment…Receptors receive information o Sensory neurons send those signals from the spinal column to the brain… Neurons in the body send those signals to CNS  What do interneurons do o Interneurons are the INTERMEDIATE neuron that makes connections between sensory neurons and motor neurons which perform the proper reaction  Anatomy of neuron o Dendrites receive signals from axons. Those signals are then transferred to the cell body where they are interpreted and sent to the axon to send to other neurons  Membrane potentials o A membrane potential exists when there is a difference in charge in either side of the membrane  What is resting potential? How does it exist? How it is maintained o Resting potential is when a neuron is at rest in extracellular fluid and has a more positive charge on the outside and negative charge on the inside o Resting potential exists because there is a difference in charge in membrane potential o Resting potential is maintained because ions can only move in or out of a cell if an action potential is generated  Potassium Leak channel o When potassium leaks out of the cell making the cell more negatively charged because of the electrical gradient but moves in via concentration gradient  What does it mean if the potassium leak channel is open o If the potassium leak channel is open it means that an action potential is not occurring o The sodium potassium pump is what generates an action potential, not just potassium leak channel  Equilibrium potential o Equilibrium potential finds a balance in which potassium enters and exits a cell  Importance of sodium potassium pump in electrical potentials o The sodium potassium pump allows two potassium ions to enter the cell and 3 sodium ions to be taken out. This makes the neuron has a negative resting potential because the rate at which positive charges are leaving the cell is greater than the rate at which they are entering  Three phases of an action potential take about a millisecond to occur o 1. Depolarization  During depolarization, a threshold much be reached to begin action potential. Once the threshold is reached, it causes sodium channels to open so sodium can rush into the axon making it more positive inside the cell o 2. Repolarization  During repolarization sodium channels close as sodium moves down the axon o 3. Hyperpolarization  During hyperpolarization, positive charges exit the axon to bring it back to resting potential  Is frequency or size important when talking about if an action potential occurs o Frequency because the size of an action potentials remains the same  What channel is closed during resting potential and which ones are open? o Sodium channels are closed and potassium channels are open  What did patch clamping discover o Sodium channels open quickly after depolarization sodium channels must open quickly to have a rapid change in membrane potential o Potassium channels open with a delay after depolarization (clamping of channels)  What type of feedback occurs during depolarization o Positive feedback depolarization is when an action potential moves down a membrane and must be supported  Neurotoxins o Neurotoxins block sodium channels which slow action potentials  ***How is the action potential promoted*** o Action potentials are promoted when sodium enters the cell (depolarization) causing the inside of the cell to be more positive than outside. Like charges repel and send sodium ions down the axon and open more sodium channels along the way making it a positive feedback system. Once that occurs, around 40mV, repolarization occurs and potassium ions rush out of the cell (potassium leak channel) making inside more negative. Then the sodium potassium pump occurs during hyperpolarization  Does action potential signal diminish as it moves down the axon? Can the action potential go backwards? o action potentials do not diminish and do not go backward  How does the diameter of an axon effect its speed? o Larger axons move ions faster because they have less sodium channels to open up  How does myelination effect speed o when the axon is mylenated it moves faster  What is the job of schwann cells o To keep Na from leaking … schwann cells do not want sodium to exit because it will effect the action potential rate  what happens if axon is unmylenated o multiple sclerosis develops which makes action potentials very slow  what is the sending and receiving cell called