Bio 252 Exam 1 Study Guide

Bio 252 Exam 1 Study Guide Three fundamental physiological properties of neurons, or nerve cells - Ans:-Excitability Conductivity Secretion Excitability - Ans:-the ability of a cell to respond to a stimulus, especially the ability of nerve and muscle cells to produce membrane voltage changes in response to stimuli; also called irritability -all cells are excitable -nerve cells are excitable to the highest degree Conductivity - Ans:-Neurons respond to stimuli by producing electrical signals that are quickly conducted to other cells at distant locations Secretion - Ans:-When the signal reaches the end of a nerve fiber, the neuron secretes a neurotransmitter that crosses the gap and stimulates the next cell Three classes of neurons - Ans:-Sensory Motor ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 2/6 Interneurons Sensory neurons - Ans:-Afferent = signal conduction towards the CNS -conduct signals from receptors to the CNS -are specialized to detect stimuli such as light, heat, pressure, and chemicals, and transmit information about them to the CNS -these neurons begin in almost every organ in the body and end in the CNS Interneuron - Ans:--Association neuron -called interneurons because they lie between and interconnect incoming sensory pathways and outgoing motor pathways -confined to the CNS -receive signals from many other neurons and carry out the integrative function of the nervous system = they process, story, and receive information and "make decisions" that determine how the body responds to a stimuli -90% of our neurons are interneurons - Motor - Ans:--Efferent = signifies conduction away from CNS ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 3/6 -conduct signals from the CNS to effectors such as muscles and glands -called motor cause most lead to muscle cells - Soma - Ans:--control center of a neuron -neurosoma or cell body -contains a centrally located nucleus with a large nucleolus -cytoplasm contains mitochondria, lysosomes, a golgi complex, numerous inclusions, and extensive rough ER and cytoskeleton =cytoskeleton = consists of a dense mesh of microtubules and neurofibrils (bundles of actin filaments) which compartmentalize the rough ER into dark-staining regions called Nissl bodies Nissl Bodies - Ans:--unique to neurons so are helpful in identifying them in tissue sections with mixed cell types Dendrites - Ans:-extensions of neurons that receives information from other cells or from environmental stimuli, and conducts signals to the soma Axon - Ans:-transmits action potentials -only one axon in a neuron ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 4/6 -much longer and less branched than dendrites Neurons make up what percent of nervous tissue? - Ans:-50% Are there more neurons or glial cells? - Ans:-tons more glial cells, outnumber neurons 10:1 Glial cells - Ans:-protect the neurons and help them function Neuroglia of CNS - Ans:-oligodendrocyte