(or roof) of the midbrain. posterior to the cerebral aqueduct. composed of corpora quadrigemina
includes: tegmentum (just ventral to aqueduct. contains medial lemniscus and red nuc.). substantia nigra (toward middle). crus cerebri (ventral and lateral aspect)
smallest of the cranial nerves. innervates superior oblique muscle of eye. travels the furthest inside crainial vault. fibers cross over as they exit
origin is ventral from interpeduncular fossa. 6 nuclei of origin located in periaqueductal gray substance. innervates 4 of 6 eye muscles. lifts up your eye lids
four bumbs called superior and inferior colliculi. superior deal with some visual reflexes. inferior deal with some auditory reflexes. utilize tectospinal tract (move head from sound)
nuclei of origin for cn 3 and 4. reticular formation of midbrain located here. red nucleus. part of the cerebral peduncles
may or may not be part of reticular formation. superior part extends into diencephalon's subthalamic region. inf large area (magnocellular) and highly vascular sup area (parvocellular). originate in magnocellular area of midbrain. input fibers from central cerebellar nuclei. funct: contralateral motor responses for postural control and muscle tone primarily in flexor musculature.
located between tegmentum and crus. extends to subthalamus. "black substance" greatest development is in man. melanin gives it black appearance. af and ef fibers exchanged to telecephalon's caudate and putamen nuclei. (parkinsons disease)
composed of descending tracts of fibers from cerebral cortex. corticospinal, pontine, bulbar (M.O) and mesencephalic fibers. terminate in cn 3 and 4 to initiate voluntary motor movements of teh eyes
secondary embryonic vesicle from the prosencephalon. means between brain.
most significant relay center for sensory input to cerebrum. integrative as well as relay (pain). control of autonomic and endocrine functions. made of: 3rd ventricle, epithalamus, thalamus, hypothalamus, subthalamus
(pineal gland body and post commissure) does calcify with age. tumors do occur. is built like an endocrine gland with fenestrated capillaries and secretes melatonin, seratonin and norep. post commis: pupillary light reflex.
(largest of all nuclei in cns) lateral and medial geniculate bodies included. means couch. forms the bulk of the side of the 3rd ventricle. funct: all sensory input to cerebral hemispheres except olfaction is relayed and somewhat integrated here. some thermal and pain sensations.
forms floor of 3rd ventricle. includes: infundibular stalk and optic chiasma (not the pituitary gland). funct: vague control over basic drives of hunger, thirst and sex. controls physical aspects of emotional expression (crying, higher heart rate) parasymp control: increases digestive motility, decreases heart rate, constriction of pupil. symp control: increases heart rate and vasoconstriction, decreases digestive motility. endocring control
(division of hypothalamus) 1.supraoptic, 2.paraventricular, 3.suprachiasmatic, 4.anterior and 5.preopitc area nuclei. anterior known for parasympathetic functions. preoptic is thermo- regulator especially as the body heats up
supraoptic and paraventricular
(nuclei in the anterior area of hypothalamus) send axons via supraopticohypophyseal tract. terminate in post pit. both capable of releasing oxytocin and antidiuretic hormones. oxy: uterine contractions, milk let down and ejection. adh: antidiuretic hormone, increases water reabsorption
(nuclei of hypothalamus) responsible for muc of our circadial rhythms. such as temp, sleep, light, feeding. secretions into the bloodstream. connected to the pineal gland
(hypotalamus division) dorsomedial nuclie: GI tract parasympathetic influence, fairly diffuse. ventromedial: center for eating and thirst gratification. fullness center. arcuate nuclei, and tuber cinereum:undulating bulge between infundibular stalk and large mammilary bodies
contribute axons to tuberoinfundibular tract. axons terminate and secrete neurohormones into perivascular spaces. pass to anterior pituitary by bloodstream, influence release of pituitary hormones. called releasing factors. hypothalamic hypophsiotropic hormoes is newer term. part of intemediate area