Cranial Nerves & Functional Components Quiz

Questions and Answers

What is true of special afferent fibers?

Found only in the cranial nerves, true of both Special Somatic Afferent (SSA) fibers and Special Visceral Afferent (SVA) fibers.

Where are the cells of origin in the general sensory fibers?

Cells of origin in the craniospinal ganglia (Dorsal Root Ganglia; nuclei/ganglia of specific cranial nerves).

What are the two types of impulses generated by general somatic afferent (GSA) fibers?

Exteroceptive impulses and proprioceptive impulses.

General Somatic Afferent (GSA) fibers will carry exteroceptive impulses from what epithelium?

Epithelial tissue of ectodermal origin including skin of face and lining of external ear. Signup and view all the answers

How does the body sense strain or stretch in the body wall, tendons, or joints?

Proprioceptive impulses which are transferred by General Somatic Afferent (GSA) fibers. Signup and view all the answers

General visceral afferent (GVA) fibers will send sensory impulses from what regions of the body?

Visceral structures lined with epithelium of endodermal origin, including the posterior 1/3 of the tongue and the pharynx. Signup and view all the answers

What type of sensory fibers are found within blood vessels?

Visceral Afferent (GVA) fibers. Signup and view all the answers

What are some important functions of general somatic afferent (SSA) fibers?

Aid in sensory impulse transmission from the ear and eye, involved in vision, hearing, and equilibrium. Signup and view all the answers

What are some important functions of general visceral afferent (SVA) fibers?

Aid in specialized sensory impulse transmission from the nose and tongue, involved in olfactory and gustatory senses. Signup and view all the answers

What are the motor fibers that innervate the musculature of the body?

General Somatic Efferent (GSE) and General Visceral Efferent (GVE). Signup and view all the answers

What is the difference between general somatic efferent (GSE) and general visceral efferent (GVE) fibers?

GSE conveys motor impulses to somatic (skeletal) muscles; GVE are autonomic fibers that innervate smooth muscles, blood vessels, and cardiac muscle. Signup and view all the answers

What are the subdivisions of general visceral efferent (GVE) fibers?

Sympathetic and Parasympathetic. Signup and view all the answers

Which motor nerve fibers are found in cranial nerves and innervate a specialized area of the skeletal musculature?

Special Visceral Efferent (SVE) and Special Somatic Efferent (SSE). Signup and view all the answers

What is the important function of special visceral efferent (SVE) fibers?

Innervate skeletal muscles derived from branchiomeric/pharyngeal arch mesoderm, including muscles of mastication and facial expression. Signup and view all the answers

What is the function of special somatic efferent (SSE) fibers?

SSE nerve fibers can reflexively influence sensory input to the ear. Signup and view all the answers

What is another name for CN I and what type of fibers are found in this cranial nerve?

Olfactory nerve (CN I), carries special visceral afferent fibers only (SVA). Signup and view all the answers

What cranial nerve is responsible for the sense of smell?

Olfactory nerve (CN I), carries only SVA fibers. Signup and view all the answers

Which cranial nerve will carry afferent fibers to the retina?

Optic nerve (CN II); contains only special somatic afferent (SSA) fibers. Signup and view all the answers

Study Notes

Cranial Nerves & Functional Components

Special afferent fibers are exclusive to cranial nerves and encompass two subtypes: Special Somatic Afferent (SSA) and Special Visceral Afferent (SVA).
General sensory fibers have their cells of origin in craniospinal ganglia, specifically in the dorsal root ganglia and in nuclei/ganglia of certain cranial nerves.
General Somatic Afferent (GSA) fibers generate two types of impulses:
- Exteroceptive impulses originate from the epithelium of ectodermal origin.
- Proprioceptive impulses arise from sensory endings located in body wall tendons and joints.
GSA fibers transmit exteroceptive impulses related to pain, temperature, and touch from ectodermal-derived epithelium. This includes:
- Facial skin
- Lining of external ear and tympanic membrane
- Conjunctiva of the eye
- Nasal cavity and paranasal sinuses
- Oral cavity and anterior two-thirds of the tongue
- Lining of the cranial cavity (dura mater)
The body senses strain or stretch in tendons, body walls, or joints via proprioceptive impulses processed by GSA fibers.
General Visceral Afferent (GVA) fibers transmit sensory impulses from visceral structures arising from endodermal origin, such as:
- Posterior one-third of the tongue
- Ducts of parotid gland
- Carotid sinus
- Pharynx, middle ear, and larynx
- Bronchial tree, esophagus, and gastrointestinal ducts
GVA fibers are also present in blood vessels, despite them being derived from mesoderm, as GVA fibers typically relate to endodermal-derived structures.
General Somatic Afferent (SSA) fibers play an important role in sensory transmission from the ear and eye, contributing to vision, hearing, and equilibrium.
General Visceral Afferent (SVA) fibers aid in transmitting specialized sensory impulses from the nose and tongue, responsible for olfactory (smell) and gustatory (taste) functions.
General Somatic Efferent (GSE) fibers and General Visceral Efferent (GVE) fibers are the primary motor fibers that innervate body muscles.
GSE fibers convey motor impulses to skeletal muscles, while GVE fibers, known as autonomic fibers, innervate smooth muscles in the gut tube, blood vessels, arrector pili, and cardiac muscle.
GVE fibers are subdivided into:
- Sympathetic fibers found in all spinal nerves and some cranial nerves.
- Parasympathetic fibers located in cranial nerves III, VII, IX, X, and pelvic spinal nerves S2-S4.
Special Visceral Efferent (SVE) fibers innervate skeletal muscles derived from branchiomeric/pharyngeal arch mesoderm, including muscles for mastication, facial expression, pharynx, palate, and larynx.
Special Somatic Efferent (SSE) fibers reflexively influence sensory input to the ear.
The Olfactory nerve (CN I) is known for carrying only SVA fibers, enabling the sense of smell, and facilitating reflex actions such as salivation and increased gastric motility.
CN I is exclusively responsible for the sense of smell and contains only SVA fibers.
The Optic nerve (CN II) carries afferent fibers to the retina and consists solely of special somatic afferent (SSA) fibers, primarily involved in vision.

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Test your knowledge on cranial nerves and their functional components with these flashcards. This quiz covers aspects like special afferent fibers and the origin of general sensory fibers, essential for understanding neuroanatomy. Perfect for students of anatomy or neuroscience.