and H\' Gray a ie Mater The spinal cord is composed of gray matter and whise Gra
ID: 133752 • Letter: A
Question
and H' Gray a ie Mater The spinal cord is composed of gray matter and whise Gray Mam The gray matorsal horns y matter is easily recognized beceuse it picks up more dye in the staining process. Norice that the gray matter and the vestral horns are the lower extensions of the hape. The horns are the wpper ex eray matter that account for the butterfly shape you also may be able to see groups of cells that form the dorsal root ganglia and connect with the dorsal horns. In the vestral horns, look for the triangular-shaped cells and associated fibers White matter is composed only of long fibers that are Theve long fibers are carrying impulses from the cord to the brain bound together), 3Do you see any signs of cells in the white matter? covered by a white, glistening sheath called myelin. and from the brain to the cord. They form the ascending and descending tracts (many long fibers Spinal Nerves Before we begin our study of spinal serves, it will be helpful to review soeme basic information. Nerve cells are neurons and every neuron has three parts: The cell body is the part of the neuron that contains the eucleus and other organelles A dendrite is an extension (process) of the cell body that conducts nerve impuises toward the cell body An axon is an extension (process) of the cell body that conducts nerve i impulses away from the cell body. Figure 15.Sa is a diagram of the spinal cord and a spinal nerve. The following questions I. Considering the direction of arrows in figure 15.Sa, what portion of the sensory neuron is in the are based on this diagram. eerve? Where is the cell body of the sensory neuron? Where is the axon of the sensory neuron? What is the function of the sensory neuron? 2. What portion of the motor neuron is in the nerve Where is the cell body of the motor neuron? Where are the dendrites of the motor neuron? What is the function of the motor neuron? 3. Why are spinal nerves called mixed nerves? Microscopic Examination of a Spinal Nerve Examine a slide of a nerve in cross section and notice the large number of lightly stained circular structures, some surrounded by a myelin sheath produced by Schwann cells. As depicted in figure 15.6, these structures are cross sections of numerous axons and/or dendrites arranged in bundles with a common connective tissue covering. The slide also may contain a cross section of a small artery and vein.Explanation / Answer
1)a
b- The cell bodies of the sensory neurons are located in dorsal root ganglia in clusters next to spinal cord.
c- The axon( nerve fibres) runs in both directions.ie peripheral axon to receptors and central axon to spinal cord.
d - Sensory neurons convert the external stimuli from organisms environment into internal electrical impulses.
2) a
b - The cell bodies are located in the ventral horn of the spinal cord grey matter and in the motor nuclei of brain stem.
c-Dendritres are located in the spinal cord.
d - Coducts impulses to the muscle or gland from brain
3 ) Spinal nerves are called mixed nerves because their posterior roots contain sensory axons and anterior roots contain motor axons.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.