CRANIAL NERVES HAPS-I Course Special Project JULIANN GARZA, PA-C, MS UNIVERSITY OF TEXAS-PAN AMERICAN

Objectives Identify the general functions and classifications of the nervous system. Differentiate the parts and functions of the central nervous system and peripheral nervous system. Create a 3-dimensional model of cranial nerves. Identify the cranial nerves by number, name, and major functions of each. Apply cranial nerve information into clinical correlations and case studies.

Nervous System Central Nervous System Peripheral Nervous System

Consists of brain and spinal cord Interprets incoming sensory information and issues instructions Consists of nerves that extend from spinal cord and brain Serve as the communication lines, linking parts of the body by carrying impulses from the sensory receptors to the CNS and to the appropriate glands or muscles Central Nervous System Peripheral Nervous System

Nervous System CNSPNS Efferent (motor division) Afferent (sensory divison)

Nervous System CNSPNS Efferent (Motor) division SomaticAutonomic Afferent (Sensory division)

Nervous System CNSPNS Efferent (Motor) Division SomaticAutonomicSympatheticParasympath. Afferent (Sensory) Division

Structure of a Nerve in the Peripheral Nervous System Nervous tissue is made up of 2 principal types of cells: 1.Supporting cells 2.Neurons

Supporting Cells Neurons Schwann cells: form the myelin sheath around nerve fibers Satellite cells: act as protection and cushioning for the cells The nerve cells are specialized to transmit messages from one part of the body to another ALL contain a cell body and projection like fibers Peripheral Nervous System

Functional Classification of Neurons Sensory (Afferent) Nerves Motor (Efferent) Nerves Mixed Nerves

Types of Nerves in the Peripheral Nervous System Spinal Nerves  31 pairs  Formed by the combination of the ventral and dorsal roots of the spinal cord  Named according to region of cord from which they arise Cranial Nerves  12 pairs  Serve head and neck  Numbered in order  Described by name, number, and major function

Cranial Nerves

Cranial Nerve I Olfactory Origin/Course Fibers arise from olfactory receptors in the nasal mucosa Function Sensory: carries impulses for the sense of smell Add Corresponding Illustration Here

Cranial Nerve II Optic Origin/Course -Fibers arise from the retina of the eye and form the optic nerve -The 2 optic nerves form the optic chiasma -The fibers continue to the optic cortex as the optic tracts Function Sensory: carries impulses for vision Add Corresponding Illustration Here

Cranial Nerve III Oculomotor Origin/Course Fibers run from the midbrain to the eye Function Motor: supplies motor fibers to four of the 6 eye muscles that direct the eyeball and eyelid -Supplies internal eye muscles controlling lens and pupil size Add Corresponding Illustration Here

Cranial Nerve IV Trochlear Origin/Course Fibers run from midbrain to the eye Function Motor: supplies motor fibers for one external eye muscle (superior oblique) Add Corresponding Illustration Here

Cranial Nerve V Trigeminal Origin/Course Fibers emerge from the pons and form three divisions that run to the face Function Sensory: carries impulses from the skin of the face and mucosa of the nose and mouth Motor: activate chewing muscles Add Corresponding Illustration Here

Cranial Nerve VI Abducens Origin/Course Fibers leave pons and run to the eye Function Motor: supplies movement to lateral rectus muscle, which rolls the eye laterally Add Corresponding Illustration Here

Cranial Nerve VII Facial Nerve Origin/Course Fibers leave the pons and run to the face Function Sensory: carries impulses for the sense of taste Motor: activates the muscles of facial expression and the lacrimal and salivary glands Add Corresponding Illustration Here

Cranial Nerve VIII Vestibulocochlear Origin/Course Fibers run from the equilibrium and hearing receptors of the inner ear to the brain stem Function Sensory: transmits impulses for the sense of balance and hearing Add Corresponding Illustration Here

Cranial Nerve IX Glossopharyngeal Origin/Course Fibers emerge from the medulla and run to the throat Function Motor: supplies motor fibers to throat that promote swallowing and saliva production Sensory: carries sensory impulses from taste buds of the posterior tongue and from pressure receptors of the carotid artery Add Corresponding Illustration Here

Cranial Nerve X Vagus Origin/Course Fibers emerge from the medulla and descend into the thorax and abdominal cavity Function Fibers carry sensory impulses from and motor impulses to the pharynx, larynx, and the abdominal and thoracic viscera that aid in digestion and regulate heart activity Add Corresponding Illustration Here

Cranial Nerve XI Accessory Origin/Course Fibers arise from the medulla and superior spinal cord and travel to muscles of the neck and back Function Motor: activate the sternocleidomastoid and trapezius muscles Add Corresponding Illustration Here

Cranial Nerve XII Hypoglossal Origin/Course Fibers run from the medulla to the tongue Function Sensory: carry impulses from the tongue Motor: control tongue movements Add Corresponding Illustration Here

References Marieb, E. Essentials of Human Anatomy & Physiology. Pearson Benjamin Cummings, 2009.