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Anatomy & Physiology: Nervous System and Cranial Nerves

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이 집합의 용어 (22)

  • What are the three main functions of the nervous system?
    Sensory input (monitoring stimuli), Integration (interpretation of sensory input), and Motor output (response by activating effector organs).
  • What are the two main divisions of the nervous system?
    Central nervous system (CNS) consisting of the brain and spinal cord, and Peripheral nervous system (PNS) consisting of cranial and spinal nerves.
  • What are the two functional divisions of the Peripheral Nervous System (PNS)?
    Sensory (afferent) division carries impulses to the CNS; Motor (efferent) division transmits impulses from the CNS to effector organs.
  • What connective tissue layers surround a nerve in the PNS?
    Endoneurium surrounds individual axons, Perineurium bundles fibers into fascicles, and Epineurium is the tough outer sheath around the nerve.
  • What are mixed nerves?
    Nerves containing both sensory and motor fibers that carry impulses to and from the CNS; most common type of nerve.
  • How many pairs of cranial nerves are there and what functions do they serve?
    There are 12 pairs of cranial nerves; they have sensory, motor, or both sensory and motor functions.
  • What is the function of the Olfactory nerve (Cranial Nerve I)?
    Carries afferent impulses for the sense of smell from the olfactory epithelium to the brain.
  • Describe the pathway and function of the Optic nerve (Cranial Nerve II).
    Arises from the retina, passes through optic canals, converges at the optic chiasm, and transmits afferent impulses for vision to the visual cortex.
  • What are the main functions of the Oculomotor nerve (Cranial Nerve III)?
    Controls eyelid elevation, eyeball movement, iris constriction, and lens shape for focusing; contains parasympathetic fibers.
  • What muscle does the Trochlear nerve (Cranial Nerve IV) innervate?
    Innervates the superior oblique muscle of the eye, primarily a motor nerve directing eyeball movement.
  • What are the three divisions of the Trigeminal nerve (Cranial Nerve V) and their functions?
    Ophthalmic (V1) and Maxillary (V2) divisions carry sensory impulses from the face; Mandibular (V3) carries sensory impulses and motor fibers for mastication.
  • What is the primary function of the Abducens nerve (Cranial Nerve VI)?
    Primarily a motor nerve that innervates the lateral rectus muscle to abduct the eyeball.
  • What are the motor and sensory functions of the Facial nerve (Cranial Nerve VII)?
    Motor for facial expression and autonomic impulses to lacrimal and salivary glands; sensory for taste from anterior two-thirds of the tongue.
  • What are the two divisions of the Vestibulocochlear nerve (Cranial Nerve VIII) and their functions?
    Cochlear division for hearing and Vestibular division for balance; functions solely sensory.
  • What are the motor and sensory roles of the Glossopharyngeal nerve (Cranial Nerve IX)?
    Motor innervation to part of the tongue, pharynx, and parotid gland; sensory for taste and general sensation from tongue and pharynx.
  • What is unique about the Vagus nerve (Cranial Nerve X)?
    It extends beyond the head and neck to thoracic and abdominal organs; mixed nerve with parasympathetic motor fibers and sensory functions including taste.
  • What muscles does the Accessory nerve (Cranial Nerve XI) innervate?
    Primarily motor; supplies fibers to the larynx, pharynx, soft palate, trapezius, and sternocleidomastoid muscles.
  • What is the function of the Hypoglossal nerve (Cranial Nerve XII)?
    Motor innervation to intrinsic and extrinsic muscles of the tongue, aiding in swallowing and speech.
  • How many pairs of spinal nerves are there and how are they named?
    There are 31 pairs of mixed spinal nerves named according to their point of issue: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal.
  • What are nerve plexuses and their significance?
    Interlacing nerve networks formed by ventral rami (except T2-T12); they ensure muscles receive nerve fibers from multiple spinal nerves, preventing complete paralysis from single nerve damage.
  • What is the cervical plexus and its most important nerve?
    Formed by ventral rami of C1-C4; most branches are cutaneous nerves; the phrenic nerve is the major motor and sensory nerve of the diaphragm.
  • What regions do the brachial, lumbar, and sacral plexuses serve?
    Brachial plexus (C5-T1) innervates the upper limb; lumbar plexus (L1-L4) innervates thigh and abdominal wall; sacral plexus (L4-S4) serves buttock, lower limb, pelvic structures, and perineum.