Chpt 14 handout/ Homeostatic imbalance, T and F

Terms in this set (11)

1. Their origin sites. Parasympathetic (axon) fibers emerge from the brain and sacral spinal cord (are craniosacral). Sympathetic fibers (axons) originate in the thoracolumbar region of the spinal cord.

2. The relative lengths of their fibers. The parasympathetic division has long preganglionic and short postganglionic fibers. The sympathetic division has the opposite condition.

3.The location of their ganglia. Most parasympathetic
ganglia are located in the visceral effector organs. Sympathetic ganglia lie close to the spinal cord.

A. Parasympathetic (Craniosacral) Division (pp. 529-530; Figs. 14.3-14.4; Table 14.1)
1. The preganglionic axons extend from the CNS nearly all the way to the structures to be innervated, where they synapse with ganglionic neurons in the terminal ganglia.
2. The cranial outflow consists of preganglionic fibers that run in the oculomotor, facial, glossopharyngeal, and vagus cranial nerves.
3. The rest of the large intestine and the pelvic organs are served by the sacral outflow, which arises from neurons located in the lateral gray matter of spinal cord segments S2-S4.
B. Sympathetic (Thoracolumbar) Division (pp. 530-534; Figs. 14.3, 14.5-14.6; Table 14.1)
1. The sympathetic division supplies the visceral organs in the internal body cavities but also all visceral structures in the somatic part of the body.
2. When synapses are made in chain ganglia, the postganglionic axons enter the ventral (or dorsal) ramus of the adjoining spinal nerves by way of communicating branches called gray rami communicantes.
3. The preganglionic fibers from T5 down synapse in collateral ganglia; thus these fibers enter and leave the sympathetic chains without synapsing.
4. Some fibers of the thoracic splanchnic nerves terminate by synapsing with the hormone-producing medullary cells of the adrenal cortex. 0p