Anatomy Flashcards
What is the function of the lateral area of the hypothalamus? What does destruction result in?
Hunger
Destruction leads to anorexia, failure to thrive in infants.
What is the function of the suprachiasmatic nucleus?
Circadian rhythm
What is the function of the ventromedial area of the hypothalamus? What does destruction result in?
Satiety
Destruction results in hyperphagia.
What parts of the hypothalamus does leptin act on? What is the effect?
- INHIBITS the lateral area, which suppresses hunger
- STIMULATES the ventromedial area, which activates satiety
What is the function of the anterior hypothalamus? Damage leads to?
Cooling, parasympathetic
damage leads to heat intolerance
(Anterior, parAsympathetic, A/C = anterior, cooling)
What is the function of the posterior hypothalamus? Damage leads to?
Heating, sympathetic
damage leads to cold intolerance
Loss of touch sensation affecting the entire right side (upper and lower extremities, face) represents a lesion where? No motor deficits.
lesion of left thalamus
Thalamic syndrome – total sensory loss on contralateral side of body
damage to thalamic VPL and VPM nuclei = complete contralateral sensory loss
What mutation is associated with ALS? How can you differentiate between ALS and syringomyelia?
zinc-copper superoxide dismutase mutation (SOD1) – free radical injury in neurons
most cases are sporadic
Syringomyelia has sensory loss – loss of pain and temperature sensation.
NO SENSORY LOSS IN ALS.
What sensory system uses the lateral geniculate nucleus as a relay nucleus? The medial geniculate nucleus?
LGN of the thalamus = visual information
sends visual info from the optic tracts to the visual cortex
MGN of the thalamus = auditory information
sends auditory info from the superior olive and inferior colliculus of the pons to the auditory cortex (temporal lobe)
Nausea and vomiting after chemotherapy due to activation of what site in the brain?
chemoreceptor trigger zone (CTZ), dorsal surface of the medulla
located in the area postrema (no BBB, so samples chemicals circulating in blood)
What lobe does Meyer’s loop run through from the lateral geniculate nucleus? What lobe do the dorsal optic radiations run through?
Meyer’s loop (lower retina, upper visual field) takes a circuitous route anteriorly through the TEMPORAL lobe
Dorsal optic radiations (upper retina, lower visual field) pass from the LGN through the PARIETAL lobe
Which nerve damaged if loss of sensation in pinky? What deformity?
Ulnar nerve
“claw hand”
Describe the path of the pupillary light reflex.
Optic nerve, chiasma, tract, LGN to pretectal nucleus to bilateral Edinger-Westphal nuclei to ciliary ganglion (travels with CN III) to the pupillary constrictor muscle
Neurofibromas in neurofibromatosis I are derived from what cells?
neural crest cells
Lesion which cranial nerve leads to hyperacusis (increased sensitivity to sound)?
Facial nerve
innervates the stapedius muscle, which stabilizes the stapes ossicle
Which sense does not have a relay nucleus in the thalamus? What are the relay nuclei in the thalamus and what sensory pathways do they relay?
Olfactory
Ventral posterolateral (VPL) = ALS, dorsal columns Ventral posteromedial (VPM) = trigeminal, gustatory/taste Lateral geniculate (LGN) = vision Medial geniculate (MGN) = auditory
Injury of which nerve leads to “wrist drop”?
radial nerve injury
weakness of forearm and hand extensors
Where do the three branches of CN V exit the skull?
Standing Room Only
V1: Superior orbital fissure
V2: foramen Rotundum
V3: foramen Ovale
Injury to what nerve causes “foot drop”?
Common peroneal injury
cannot dorsiflex or evert foot
characteristic high-stepping gait seen
Name the 3 important dopaminergic systems, their function, and associated disease.
Mesolimbic-mesocortical
- regulates behavior
- hyperactive in schizophrenia
Nigrostriatal
- coordination of voluntary movements
- decreased activity in Parkinson’s
Tuberinfundibular
- controls prolactin secretion via dopamine-dependent prolactin tonic inhibiton
- block of pathway results in hyperprolactinemia
Where does the trigeminal nerve arise?
level of the middle cerebellar peduncle at lateral aspect of the mid-pons
Afferent limb of gag reflex? Efferent?
Glossopharyngeal (CN IX) - afferent
Vagus (CN X) - efferent
Palsy of which nerve is responsible for VERTICAL diplopia? Classic presenting symptom?
CN IV (trochlear nerve -- superior oblique) injury to CN IV means eye is deviated upward
double vision when walking down stairs or reading newspaper
most noticeable when eye looking down toward nose
What nerves in addition to CN VIII can be affected by an acoustic neuroma at the cerebellopontine angle?
CN V (trigeminal) and CN VII (facial)
What connects the lateral ventricles to the 3rd? The 3rd to the 4th ventricle? The 4th to the subarachnoid space?
Lateral ventricles to 3rd: two foramina of Monro
3rd to 4th: cerebral aqueduct
4th to subarachnoid: two foramina of Luschka (lateral) and foramen of Magendie (medial)
What provides general sensation to the anterior 2/3 of the tongue? Gustatory innervation?
general sensation: mandibular branch of trigeminal (V3)
gustatory innervation: chorda tympani branch of facial nerve (VII)
What nerves mediate the ankle jerk reflex? The anocutaneous reflex?
Ankle jerk/Achilles reflex: S1-S2
tests the integrity of the sciatic nerve
Anocutaneous reflex: S2-S4
tests integrity of the pudendal nerve that innervates perineum
damage also causes saddle anesthesia
