innervate

Examples of innervate in the following topics:

• Trochlear (IV) Nerve

  • The trochlear nerve (cranial nerve IV) is a motor nerve that innervates a single muscle: the superior oblique muscle of the eye.
  • The trochlear nerve (cranial nerve IV) is a motor nerve that innervates a single muscle: the superior oblique muscle of the eye.
  • Other than the optic nerve (cranial nerve II), it is the only cranial nerve that decussates (crosses to the other side) before innervating its target.
  • Lesions of all other cranial nuclei affect the ipsilateral side (except of course the optic nerve, cranial nerve II, which innervates both eyes).
  • The unique features of the trochlear nerve, including its dorsal exit from the brainstem and its contralateral innervation, are seen in the primitive brains of sharks.

• Motor Units

  • The motor unit is the functional unit of muscle contraction and includes the motor nerve fiber and the muscle fibers it innervates.
  • A motor unit consists of the motor neuron and the grouping of muscle fibers innervated by the neuron.
  • Groups of motor units are innervated to coordinate contraction of a whole muscle and generate appropriate movement; all of the motor units within a muscle are considered a motor pool.

• Overview of Motor Integration

  • A motor unit is comprised of a single alpha-motor neuron and all the muscle fibers it innervates.
  • A motor unit consists of a single alpha motor neuron and all of the corresponding muscle fibers it innervates; all of these fibers will be of the same type (either fast twitch or slow twitch).
  • In general, the number of muscle fibers innervated by a motor unit is a function of a muscle's need for refined motion.
  • Muscles requiring more refined motion are innervated by motor units that synapse with fewer muscle fibers.
  • The more precise the action of the muscle, the fewer fibers innervated.

• Nerve and Blood Supply

  • Synovial joints are highly innervated but vascularized indirectly by nearby tissues.
  • The articular capsule is highly innervated but avascular (lacking blood and lymph vessels), and receives nutrition from the surrounding blood supply via either the slow process of diffusion or convection, a far more efficient process.

• Pulled Groin

  • The groin is innervated by the obturator nerve, with two exceptions.
  • The pectineus muscle is innervated by the femoral nerve, and the hamstring portion of adductor magnus is innervated by tibial nerve.
  • This difference in innervation has caused some dispute whether or not the pectineus belongs to this groin and adduction group even though it still adducts the thigh.

• Parasympathetic (Craniosacral) Division

  • Parasympathetic ganglia are the autonomic ganglia of the parasympathetic nervous system which lie near or within the organs they innervate.
  • Most are small terminal ganglia or intramural ganglia, so named because they lie near or within (respectively) the organs they innervate.
  • These paired ganglia supply all parasympathetic innervation to the head and neck: ciliary ganglion (spincter pupillae, ciliary muscle), pterygopalatine ganglion (lacrimal gland, glands of nasal cavity), submandibular ganglion (submandibular and sublingual glands), and otic ganglion (parotid gland).

• Abducens (VI) Nerve

  • The abducens nerve (cranial nerve VI) controls the lateral movement of the eye through innervation of the lateral rectus muscle.
  • In most other mammals it also innervates the musculus retractor bulbi, which can retract the eye for protection.
  • It then enters the orbit through the superior orbital fissure and innervates the lateral rectus muscle of the eye.

• Hypoglossal (XII) Nerve

  • The hypoglossal nerve is the twelfth cranial nerve (XII) and innervates all extrinsic and intrinsic muscles of the tongue, except for the palatoglossus.
  • It supplies motor fibers to all of the muscles of the tongue, with the exception of the palatoglossus muscle, which is innervated by the vagus nerve (cranial nerve X) or, according to some classifications, by fibers from the glossopharyngeal nerve (cranial nerve IX) that hitchhike within the vagus.
  • Several corticonuclear-originating fibers supply innervation and aid in the unconscious movements required upon engaging in speech and articulation.
  • Schematic image of the hypoglossal nerve and the structures it innervates.

• Brachial Plexus

  • It is a collection of nerves passing through the cervico-axillary canal to reach the axilla and innervate the brachium, the antebrachium, and the hand.
  • The brachial plexus is responsible for cutaneous and muscular innervation of the entire upper limb, with two exceptions: the trapezius muscle is innervated by the spinal accessory nerve (CN XI) and an area of skin near the axilla is innervated by the intercostobrachial nerve.

• Autonomic Plexuses

  • Autonomic plexuses are formed from both sympathetic and parasympathetic fibers and innervate visceral organs to regulate overall activity.
  • Instead they provide a complex innervation pattern to the target organs, since most organs are innervated by both divisions of the autonomic nervous system.
  • Cardiac: The cardiac plexus is a plexus of nerves situated at the base of the heart that innervates the heart.