BIO 225 Exam 2 Questions with Correct Answers Latest Update 2025/2026

BIO 225 Exam 2 Questions with Correct Answers Latest Update 2025/2026 Vertebrate Central Nervous system - Answers The vertebrate central nervous system consists of the brain and spinal cord Brain - integrating center Spinal Cord - mediates information flow between brain and body Nuclei - groups of neuronal cell bodies within the CNS Tracts - bundles of many axons within the CNS Vertebrate Peripheral Nervous System - Answers Consists of all the neurons outside of the CNS (sensory and motor neurons, axons) Nerves - bundles of many axons outside of the CNS Consist of myelinated and unmyelinated axons enclosed in connective tissue May contain sensory or motor or both Cranial vs. spinal (depending on where they connect from) Ganglia - group of neuronal cell bodies outside of the CNS Grey vs White matter - Answers The brain and spinal cord consist of grey and white matter White matter has shiny, bright appearance Primarily composed of myelinated axons Grey matter has dulled appearance Contains dendrites, cell bodies, and unmyelinated axons Structure and function of spinal cord - Answers Mediates spinal reflexes Pathway for impulses to and from the brain Receives afferent/sensory signals via dorsal root Somatosensory neuron cell bodies in the dorsal root ganglion Most cells in dorsal root ganglia are unipolar Sends out efferent/motor signals via ventral root Motor neuron cell bodies in the ventral horn Simple Reflex Arc - Answers require only two neurons - one sensory neuron and one motor neuron Complex Reflex Arcs - Answers Most reflex ars are mediated by more neurons and employ divergence The withdrawal reflex must activate and inhibit motor neurons to ensure a coordinated response A single sensory neuron synapses into interneuron The interneuron synapses onto many targets and spreads the signal by "divergence" to many motor neurons Contralateral - Answers Most signals between the body and the brain (and vice versa) and contralateral Ascending tracts carry afferent/sensory signals within the CNS Descending tracts carry efferent/motor signals within the CNS These tracts make up the white matter in the spinal cord Parts of the Brain - Answers Medulla oblongata Regulates breathing, HR, blood pressure Pons Communicates between medulla, cerebellum, and forebrain Cerebellum coordinates motor behaviors The forebrain, or cerebrum, controls "higher" processes Includes four lobes Frontal Temporal Parietal Occipital The corpus callosum, a white matter tract, connects the left and right cerebral hemispheres Cerebral cortex, which is the grey surface matter, can be divided into functional domains