Lecture Quiz 2 Flashcards
Describe the diencephalon
central core of the forebrain
encloses third ventricle
deep to the basal nucle
What does the diencephalon consis of?
thalamus
hypothalamus
epithalamus
Descibe the thalamus
paired egg-shaped masses that form the superolateral walls of the third ventricle
connected at the midline by the intermediate mass
80% of diencephalon
What are the four groups of nuclei found in the thalamus?
anterior
netral
dorsal
posterior
Want do the nuclei of the thalamus do?
acts as relay center
project and receive fibers from cerebral cortex
Describe how impulses travel through the thalamus
sensual afferent impulses converge and synapse here
impulses of similar function are sorted out, edited, and relayed as a group
all inputs ascending to the cerebral cortex pass through the thalamus
What are the functions of the thalamus (aside from relay center)?
mediates sensation, motor activities, cortical arousal, learning, and memory
Where is the hypothalamus located?
below the thalamus
caps the brainstem and forms the inferolateral walls of the third ventricle
What are the mammillary bodies?
small paired nuclei bulging anteriorly from the hypothalamus
relay station for olfactory pathways
What is the infundibulum?
stalk of the hypothalamus
connects to the pituitary gland
main visceral control center of the body
What are the visceral functions of the hypothalamus?
regulates blood pressure, rate and force of heartbeat, digestive tract motility, rate and depth of breathing, and many other visceral activities
What are the emotional functions of the hypothalamus?
perception of pleasure, fear, and rage
What are the homeostatic functions of the hypothalamus?
regulates normal body temperature
What are the other functions of the hypothalamus?
regulates feelings of hunger and satiety
regulates sleep and sleep cycle
What are the endocrine functions of the hypothalamus?
releasing hormones control secretion of hormones by the anterior pituitary
supraoptic and paraventricular nuclei produce ADH and oxytocin
Where is the epithalamus located?
most dorsal portion of the diencephalon
forms roof of third ventricle
What does the pineal gland do?
extends from the posterior border of the epithalamus and secretes melatonin
What does melatonin do?
a hormone involved with sleep regulation, sleep-wake cycles, and mood
What is the choroid plexus?
a structure that secretes cerebral spinal fluid, which is then duped into the third ventricle
What does the brain stem consis of?
three regions -
midbrain
pons
medulla oblongata
Describe the brain stem in terms of gray and white matter
similar to spinal cord but contains nuclei embedded in it (grey matter)
What are the functions of the brain stem?
controls the automatic behaviors necessary for survival
provides the pathway for tracts between higher and lower brain centers
associated with 10 of the 12 cranial nerves
Where is the midbrain lcoated?
between the diencephalon and the pons
What are the cerebral peduncles?
two bulging structures of the midbrain that contain descending pyramidal motor tracts
What is the cerebral aqueduct?
hollow tube that connects the third and fourth ventricles
What cranial nerves are found in the midbrain?
III - oculomotor
IV - trochlear
What are the other nuclei found in the midbrain?
corpora quadrigemina
superior colliculi - visual reflex centers
inferior colliculi - auditory reflex centers
substantia nigra - high content of melanin, secretes dopamine
red nucleus - largest nucleus of the reticular formation; red nuclei are relay nuclei for some descending motor pathways
Where is the pons found?
bulging brainstem region between the midbrain and the medulla oblongata
forms part of the anterior wall of the fourth ventricle
What do the fibers of the pons do?
connect higher brain centers and the spinal cord
relay impulses between motor cortex and cerebellum
What cranial nerves are found in the pons?
V - trigeminal
VI - abducens
VII - facial
Where is the medulla oblongata found?
most inferior part of the brain stem
forms ventral wall of the fourth ventricle, along with pons
contains a choroid plexus of the fourth ventricle
What are the pyramids of the medulla oblongata?
two longitudinal ridges formed by corticospinal tracts
What is decussation of the pyramids?
crossover points of the corticospinal tracts
why we have lateralization of the brain
What are the cranial nerves found in the medulla oblongata?
XIII, IX, X, XI, and XII
What are the nuclear complexes found in the medulla oblongata?
vestibular nuclear complex - equilibrium cardiovascular control center respiratory control center vasomotor center - blood pressure addition centers for - vomiting, hiccuping, swallowing, coughing, sneezing
Where is the cerebellum located?
dorsal to the pons and medulla
protrudes under the occipital lobe of the cerebrum
makes up 11% of brain’s mass