Nervous System Flashcards
Cranial Nerves
Olfactory
Optic
Oculomotor
Trochlear
Trigeminal
Abducens
Facial
Vestibulocochlear
Glossopharyngeal
Vagus
Accessory
Hypoglossal
Cranial Nerves Mnemonic
Oh Oh Oh To Touch And Feel Very Good Velvet AH!
Cranial Nerve locations
Cranial Nerve - Sensory, Motor, or Both - Mnemonic
Some Say Marry Money But My Brother Says Bad Business Marry Money
Sensory, Moter, or Both?
Olfactory
Sensory
Sensory, Moter, or Both?
Optic
Sensory
Sensory, Moter, or Both?
Oculomotor
Motor
Sensory, Moter, or Both?
Trochlear
Motor
Sensory, Moter, or Both?
Trigeminal
Both
Sensory, Moter, or Both?
Abducens
Motor
Sensory, Moter, or Both?
Facial
Both
Sensory, Moter, or Both?
Vestibulocochlear
Sensory
Sensory, Moter, or Both?
Glossopharyngeal
Both
Sensory, Moter, or Both?
Vagus
Both
Sensory, Moter, or Both?
Accessory
Motor
Sensory, Moter, or Both?
Hypoglossal
Motor
Olfactory Nerve - I
Primary Function: is the special sense of smell
Orgin: receptors of olfactory epithelium.
Travels through: cribiform plate of ethmoid.
Destination: olfactory bulbs
Olfactory receptors are specialized neurons in the roof of the nasal cavity. These are the only cranial nerves that are directly attached to the cerebrum.
Optic Nerve - II
Primary Function: is the special sense of vision
Orgin: retina of the eye
Travels through: optic canal of the sphenoid
Destination: diencephalon through the optic chiasm
Contains approximately 1 million sensory nerve fibers. Medial fibers from each nerve cross-over to the opposite side of the brain chiasm
Oculomotor Nerve - III
Primary Function: Motor movement of the eyes
Orgin: mesencephalon
Travels through: superior orbital fissure of the sphenoid
Destination: rectus, oblique muscles of the eye.
Oculomotor nerve controls 4/6 extra-ocular muscles as well as the levator palpebrae muscle
Trochlear Nerve - IV
Primary Function: Motormovements of the eyes
Orgin: mesencephalon
Travels through: superior orbital fissure of the sphenoid
Destination: superior oblique muscle.
Smallest of the cranial nerves and specially innervates the superior oblique muscle
Trigeminal Nerve - V
Primary Function: mixed sensory and motor
Orgin: opthalmic branch - orbital structures, nasal cavity
Travels through: superiororbital fissure
Destination: sensory nuclei pf the pons and the muscles of mastication
The ophthalmic branch is a sensory structure that innervate the orbital structures. The maxillary branch is also a sensory nerve that supplies the lower eyelid and upper lip.
The mandibular branch is the largest branch that contains motor fibers, which innervate the muscles of mastication
Abducens Nerve - VI
Primary Function: Motor movements of the eyes
Orgin: pons
Travels through: superior orbital fissure of the sphenoid
Destination: lateral rectus muscle
This cranial nerve specifically innervates the lateral rectus muscle of the eye. This innvervation permits lateral movements of the eye.
Facial Nerve - VII
Primary Function: mixed sensory, motor
Orgin: sensory from taste receptors and mototr nuclei in the pons
Travels through: internal acoustic meatus of the temporal bone
Destination: sensory to the sensory nuclei of the pons, somatic motor to the muscles of facial expression
Overall, the different porions of the facial nerve are responsible for deep sensations over the face and for controlling muscles in the scalp and face.
Vestibulocochlear Nerve - VIII
Primary Function: sensory and hearing
Orgin: receptors of the inner ear
Travels through: internal acoustic meatus of the temporal lobe
Destination: vestibular and cochlear nuclei of the pons and the medulla oblongata
The vestibulocochlear nerve is also known as the acoustic nerve. The cochlear branch monitors the receptors in the cochlea to sense sounds during hearing.
Glossopharyngeal Nerve - IX
Primary Function: mixed sensory and motor
Orgin: sensory from the posterior portion of the tongue, motor from the motor nuclei of the medulla oblongata
Travels through: jugular foramen
Destination: somatic motor to the pharyngeal muscles involved in swallowing, visceral motor to the parotid salivary gland.
There is a motor nuclei for the glossopharyngeal nerve in the medulla oblongata, along with the X, XI, XII cranial nerves.
Vagus Nerve - X
Primary Function: Mixed sensory and motor
Orgin: visceral sensory from the pharynx and diaphragm, and visceral motor from the motor nuclei in the medulla oblongata
Travels through: jugular foramen
Destination: sensory fibers to the sensory nuclei, visceral motor to the respiratory, cardiovascular and digestive organs.
The motor function of the vagus nerve includes modulating the heart, smooth muscles, and glands within its sensory monitoring areas.
Accessory Nerve - XI
Primary Function: motor
Orgin: motor nuclei of the spinal cord and medulla oblongata
Travels through: jugular foramen
Destination: the internal branch innervates the voluntary muscles of the palate and pharynx, and the external branch controls the sternocleidomastoid and trapezius muscles.
This nerve is made up of two branches: 1) the internal branch, which functions with the vagus nerve and, 2) the external branch, which controls the sternocleidomastoid muscle and the trapezius muscle.
Hypoglossal Nerve - XII
Primary Function: motorfunction of the tongue
Orgin: motor nuclei of the medulla oblongata
Travels through: hypoglossal canal of the occipital bone
Destination: muscles of the tongue
After exiting the skull, the hypoglassal nerve curves until it reaches the skeletal muscles of the tongue.
Upper Motor Neuron
Can excite or inhibit the lower motor neuron
Lower motor neuron
extends to the muscle fibers
Brain and Spinal cord are connected through _____ and _____ tracts as well as the _____ nuclei
sensory, motor, associated
Nervous system pathways are organized _____ in the spinal cord and according to the _____ target
bilaterally, innervation
Senosry Pathways
Monitors changes in skin and external environment
Sensory pathways: 3 types of neurons:
First order - function by delvering sensory info to the nervous system
Second order - inter-neurons located in the cell bodies or the spinal cord
Third order - synapse with the second order-neuron and deliver the sensory information to the sensory area of the cerebral cortex
Primary somatic sensory pathways:
- Dorsal column
- Spinothalamic pathway
- Spinocerebellar pathway
Dorsal Pathway
(medial lemniscal pathway)
Transmits sensation, fine touch, pressure and vibrations from the body.
Also tranmits the relative position of body parts (proprioception)
Spinothalamic Pathway
Tansmits pain, temperature, and gross touch and pressure sensations
Spinocerebellar Pathway
Transmits proprioception
Motor Pathways
- Corticospinal pathway - corticobulbar tract, lateral corticospinal, ad the anterior corticospinal tract
- Medial pathway - vestibulo, tecto, and reticulospinal pathways
- Lateral pathway - rubrospinal tract; transmits the motor commands of the body, in response to sensory information transmitted by the somatic nervous system
The motor pathways are organized into the somatic system, which _____ muscles, and the autonomic servous system, which innervates _____ muscle, _____ muscle and _____.
innervates, smooth, cardiac, glands
Medial Motor Pathway
Function by controlling the muscle tone and the gross movements of the neck, trunk, and proximal limb muscles.
Lateral Motor Pathway
Controls the muscle tone and movements of distal portions of the upper limbs, and the upper motor neurons are located in the red nucleus superior to the the reticular formation.
Gray matter
Contains majority of the neurons and neuron cell bodies
White Matter
Composed mostly of budles of myelinated axons
Tonic Receptors
Adapt slowly to the stimulas and therefore, produce and transmit action potentials over a period of time.
Example: Pain receptor
Phasic Receptors
React and adapt quickly to the stimulus and do not produce action potentials over time after a single stimulus;
Example: mechanoreceptor, which are in the skin and respond to stimuli, such as pressure
Central Adaptation
Adaptation to a stimulus that takes place in the cental nervous system.
Process involves inhibition of nuclei along the particular sensory pathway, with leads to a reduction in sensory input to the cerebral cortex of the brain.
Four general receptors
- nociceptors
- thermoreceptors
- mechanoreceptors
- chemoreceptors
Nociceptors
Pain receptors
Located in: the skin, mucsle, and joints
Cell bodies are typically located: in the dorsal root ganglia and develop from neural crest cells
Organized: into thermal, mechanical and chemoreceptors
Referred Pain
Sensed by nociceptors and classified generally as a fast or slow pain.
Fast Pain
a small cut type pain
Slow pain
Longer slower residual pain
Thermoreceptors
Detect changes in temperature
Mechanoreceptors
Responds to pressure, compression, twisting, or distortion of the receptors plasmalemmae
Located: skin, joints, tendons , and walls of the blood vessels
Baroreceptors
Detects blood pressure that flows past them and the impact it has on vessel diameter
4 types of Mechanoreceptors
- Meissners corpuscles - rapidly adapting, encapsulated
- Merkel Cells - tactile discs, unencapsulated, most sensitive, found in skin and mucous membranes
- Pacinian Corpuscles - mechanoreceptors found in the dermis; activated when skin in rapidly indented
- Ruffini’s Ending - slow adapting, found in dermis, sensitive to skin stretch, activated when items slip out of hands
Proproceptors
Monitors position of body parts.
Transmits sensory information to the spinal cord for processing
Chemoreceptors
Detect chemical stimuli in the region or location,
Located in the medulla oblongata, aorta, and the carotid arteries
Detects changes in the blood oxygination and carbon dioxide levels in the blood.
Transmits info to the CNS through the glossopharyngeal nerve
Sensory Pathways
