CRANIAL NERVES PART I. FUNCTIONAL COMPONENTS Classifications of cranial nerves consists of three letters which stand for the types of fibers in the nerve receptor type. The general area supplied by that nerve, (somatic or visceral) and the kind of nerve it is (either efferent or afferent). The terms general and special refer to how specialized the receptors for that particular sense are in their functioning. General senses are usually reserved for senses which involve either mechanoreception or pain and temperature detection. Special senses are those which involve higher centers of the brain. 1. General senses are in many cases mechanoreceptors involve very specialized receptors may refer to either somatic or visceral sensation are never associated with cranial nerves correct No. The first and third foils are correct. 2. Special senses involve only cranial nerves are associated with higher centers of the cns involve very specialized receptors involve pain and temperature sensation correct. No. The first three foils are correct. 3. Terms afferent and efferent refer to? the type of nerve the type of receptor the direction of information transfer the distance the information has to travel Correct. No. The first and rhird foils are correct. General components of cranial nerves refer to both sensory and motor functioning. (GVE) General visceral efferent is the same thing as the autonomic nervous system. This would include both spinal nerves and cranial nerves. Cranial nerves contain only parasympathetic components. Both sympathetic and parasympathetic fibers are found in spinal nerves.(GSE) General somatic efferent refers to motor nerves which innervate muscles which are derived embryologically from myotomes. Most of the skeletal muscles of the body are of this type. This component is associated with both cranial nerves and spinal nerves. 4. GSE is the same as the autonomic nervous system innervates skeletal muscle is only associated with cranial nerves innervates most of the skeletal muscles of the body That's right. That's wrong. The second and fourth foils are correct. 5. Autonomic nervous system is the same as GSE is the same as GVE is associated with only cranial nerves is made up of both parasympathetic and sympathetic nerves Correct! That's wrong. The second and fourth foils are correct. 6. Muscles which are derived embryologically from myotomes are classified as smooth muscle are innervated by the visceral nervous system are innervated by the cranial nerves only comprise most of the muscles of the body That's right. That's wrong. Only the fourth foil is correct. General sensory functioning involves both somatic and visceral sensation. Somatic sensation is classified as sensory reception near the surface of the body. These include pain and temperature reception,light touch, two point discrimination,pressure detection and vibration detection. General visceral afferent (GVA) is concerned with sensory reception in deep areas of the body. Much of this reception involves the organs and visceral connective tissue of the gut. The sensation in the gut is mostly for unconscious reflexes. The only conscious sense from these organs is pain. 7. General somatic afferent sensation only involves pain never involves pain is mostly concerned with reflexes is the classification under which pressure detection falls That's right. That's wrong. Only the fourth foil is correct. 8. General visceral afferent sensation is concerned with visceral reflexes only detects pain consciously innervates receptors deep in the body detects pressure That's right. That's wrong. The first three foils are correct. 9. Somatic sensation involves two point discrimination pain and temperature detection pressure reception light touch That's right That's wrong. All foils are correct. A unique case of the efferent system (SVE) are fibers which innervate skeletal muscle which is of branchial arch origin. There is no histological difference between this skeletal muscle and muscle derived from myotomes. The branchial arches in some lower forms is the origin of smooth muscle. The smooth muscle generally forms gills in fishes. The reason this component of cranial nerves only is referred to as special is difficult to determine. A method which may help you to remember which muscles are considered special: Think of them as muscles which show emotion (facial expression). Muscles which allow for chewing and swallowing. 10. SVE innervates skeletal muscle innervates smooth muscle in some lower forms. innervates muscles derived from branchial arches innervates muscle which is histologically the same as smooth muscle That's right. That's wrong. The first three foils are correct. 11. Skeletal muscle derived from myotomes is innervated by SVE is innervated by GSE makes up muscle fibers found in the muscles of mastication makes up muscle fibers found in the limbs That's right. That's wrong. The second and fourth foils are correct. 12. The SVE component of cranial nerves is referred to as special because the muscles are of a special type histologically the muscles have a very special way of contracting they arise from the brainstem the reason is not very apparent That's right. That's wrong. Only the fourth foil is correct. There are only two functional classifications of special senses. These are special somatic afferent and special visceral afferent. SSA refers to vision, hearing, and equilibrium. SVA refers to the sense of smell and taste. Special senses generally have complex receptors which function in a very specific manner. Special senses are only found associated with cranial nerves. Special sense receptors include for vision the retina, the cochlea for hearing, the crista and macula for equilibrium, taste buds for taste, and the olfactory epithelium for smell. SVE initiates visceral (gut) reflexes. 13. SSA fibers are involved in includes taste includes smell includes pain reception includes vision That's right. That's wrong. Only the fourth foil is correct. 14. The receptors of special somatic afferent senses include the macula retina crista cochlea That's right. That's wrong. All foils are correct. 15. Special visceral afferent (SVA) involves reflexes of digestion includes smell includes taste involves visual reflexes That's right. That's wrong. The first three foils are correct.