BIOS 252 Week 2 Online Lab; Nervous System - Introduction

Natasha Ngong Chamberlain University College of Nursing BIOS 252: Anatomy and Physiology II Professor Horn July 21, 2024 Week 2: Nervous System Lab Report List the components of the central nervous system vs the peripheral nervous system. (1 point; ½ point each) CNS: The brain, brain stem, and the spinal cord. To specify the spinal cord, the medulla, the pons, the cerebellum, the midbrain, the diencephalon, and the cerebral hemispheres PNS: Peripheral nerves, neuromuscular junctions, cranial nerves, and spinal nerves. Compare and contrast the following parts of the peripheral NS utilizing the chart: (3 points; 1/2 point each) Control (Voluntary or Involuntary) Effector Organs Somatic NS Voluntary Skeletal muscles Autonomic NS Involuntary Cardiac muscle, smooth muscles, glands Enteric NS Involuntary Gastrointestinal tract (esophagus, stomach, intestines) Label the neuron with the following terms. (½ point each for 2 ½ points) Axon, hillock, myelin sheath, soma, dendrites Myelin sheath Axon Soma Dendrites Hillock Myelin sheath Axon Soma Dendrites Hillock Name the 3 distinct phases of an action potential. (1 point each for 3 points) Depolarization occurs when a neuron gets a stimulus, allowing sodium (Na+) ions to enter the cell. The influx of positive ions makes the membrane potential less negative (more positive), shifting from a resting potential of approximately -70mV to a positive value. If the threshold potential is met, an action potential is activated. Repolarization occurs after the action potential peak when Na+ channels close and potassium (K+) channels open. When K+ ions leave the cell, the membrane potential returns to a negative value. This phase restores the cell's natural polarity, returning the membrane potential to its resting state. In hyperpolarization, the K+ channels remain open longer than necessary, resulting in an excessive outflow of K+ ions. This causes the membrane potential to become more negative than the resting potential (hyperpolarization). The K+ channels eventually close, and the sodium-potassium pump returns the membrane to its resting potential. a. What is myelin? (½ point) Myelin is a lipid-rich material produced by certain glial cells and it forms the myelin sheath by wrapping around neurons' axons in layers. b. What is its function in the myelin sheath? (1 point) The myelin sheath acts as an insulator, keeping electrical signals from dissipating while