Cranial Nerves
What sensory CN is related to vision?
CNII
Are CNs apart of the CNS or the PNS?
PNS
What are the three main types of receptors?
1. exteroceptors: receive information outside the body
2. Proprioceptors: mediate deep somatic sensation from receptors beneath the skin in the muscles, joints, tendons, and inner ear
3. Interoceptors: located throughout the internal organs, control internal states as blood pressure, stomach growling, etc., mediate sensation from the viscera (internal organs), along with visceral pain, pressure, and distention
Where does the spinal cord stop in adults vs. children?
-adults stop at the lower border of the first lumbar vertebrae
-children have longer spinal cords that stop at the upper border of the third lumbar vertebrae
How do the functions of the Fasciculus Gracilis (Tract of Goll) and the Fasciculus Cuneatus (Tract of Burdach) differ?
Tract of Goll: mangages ascending sensory information, especially pressure and touch, vibration, and kinesthetic movement of lower limbs and trunk
Tract of Burdach: manages the pressure, touch, vibration, and kinesthetic movement of the upper limbs
What are the three branches of CNV?
Ophthalmic, maxillary, and mandibular
Describe the concentrations of sodium, potassium, and chloride within a cell when a sodium potassium pump is at rest.
What is neural adaptation?
It causes the signals to slow down or stop when prolonged
-expect in pain and temperature receptors
How do spinal nerves correspond to vertebrae?
-first spinal nerve leaves between the skull and the first cervical vertebrae
- second spinal cervical nerve leaves above the corresponding vertebra and all the cervical nerves do as well
- expect the 8th cervical nerve which leaes above the first thoracic vertebrae
- remainder of the spinal nerves leave below their corresponding vertebrae
What is the sensory pathway that leads from the skin to the thalamus?
spinothalamic tract
What deficits are typically seen due to damage of CNVII?
Facial paralysis (on one side), loss of blinking control on affected side, decreased tearing, drooping of the mouth, altered sense of taste, dysarthria, anterior loss of saliva, pain in or behind the ear, sound hypersensitivity, difficulty eating or drinking
Name neurotransmitters in the CNS
-Epinephrine (adrenaline): regulates visceral functions and plays a role in a fight-or-flight
-Norepinephrine: mobilises the brain and body for action
- Serotonin: regulates mood, social behavior, appetite, and digestion; involved in transmission of pain
- Gamma Aminobutyric Acid (GABA): inhibition of the functions listed above within the brain and spinal cord; important to the cessation of activity resulting in a resting state
What pathway is used to carry bodily sensation to the brain?
General somatic sensory pathways
What are the columns of the spinal cord?
-Dorsal, ventral, and lateral
What tract collects sensory information from the Golgi tendon organs and muscle spindles and sends proprioceptive information to the cerebellum?
spinocerebellar tract
group of neurons that travel together from the brainstem to the oropharynx and laryngopharynx (including palate)
-includes nerve fibers from CNIX, CNX, and CNXI
Name 4 most important neurotransmitters in the PNS
- Epinephrine (adrenaline): regulates visceral functions and role in fight-or-flight
- Norepinephrine: mobilizes the brain and body for action
- Serotonin: regulates mood, social behavior, appetite, and digestion; involved in transmission of pain
Acetylcholine: the main chemical messenger of the PNS; activates muscles
What are the 5 types of exteroreceptors?
1. Mechanoreceptors: respond to mechanical pressure
2. Thermoreceptors: respond to change in temperature
3. Nociceptors: pain receptors
4: Photoreceptors: convert light into electrical information
5. Chemoreceptors: respond to taste (oils) and smell
What are the four zones of the spinal cord?
- Posterior funiculus: responsible for sensory information
- Anterior funiculus: responsible for motor information
- 2 lateral funiculi: mixed (both motor and sensory)
What is the efferent (motor) tract that begins in the primary cortex, premotor cortex and supplementary motor cortex?
Corticospinal tract
Why is the CNX and its branches important for speech and swallowing?
1. Pharyngeal branch: responsible for pharyngeal constriction/retraction and velar elevation during speech and swallowing
2. Superior branch: 2 branches
- Internal laryngeal: carries majority of the laryngeal sensory information, collects info from mucus membrane of the larynx to the vocal folds, base of tongue, and epiglottis
-External laryngeal: carries motor information to cricothyroid muscle and inferior pharyngeal constrictors
3. Recurrent laryngeal nerve branch: innervates all the intrinsic muscles of the larynx (not the cricothyroid) and is crucial for vocal fold adduction
What is the difference between neurofilaments and neurotubules?
neurofilaments: protein polymers which form the cytoskeleton (with neurotubules), form a network and provide structural support to the cell
Neurotubules: consist of tubulin and also help maintain the structure of the cell and form the cytoskeleton (with the neurofilaments)
What is another name for the primary sensory strip?
post-central gyrus
What are the 3 columns of white matter and their functions?
1. Dorsal funiculus/column: carries sensory information
2. Ventral funiculus/column: carries motor information
3. Lateral funiculus/column: carries both sensory and motor information
What are the two divisions of the corticospinal tract and their functions?
-Anterior corticospinal tract: descending tract for motor information for voluntary movement of the trunk muscles
-Lateral corticospinal tract: carries motor information for voluntary movements to the limbs and digits