Class 6 & 7 - Brain, Internal Structures & Functions Flashcards
The three parts of the brainstem are the…
midbrain, pons, and medulla oblongata
What is the reticular formation, where is it?
a netlike region of interspersed gray and white matter which extends the length of the brain stem
What is contained in the medulla oblongata?
all the ascending and descending tracts (white matter) that extend between the spinal cord and brain
the pyramids and decussation of the pyramids (the corticospinal tracts)
the olives containing the olivary nuclei (gray matter)
Where are the olivary nuclei found?
lateral to each pyramid in the medulla oblongata
What nuclei are found in the medulla oblongata?
olivary nuclei, inferior olivary nucleus cardiovascular center medullary respiratory center vomiting center deglutition center gracile nucleus cuneate nucleus gustatory nucleus cochlear nuclei vestibular nuclei
What does the medial lemniscus contain?
axons of the gracile and cuneate nuclei
Which cranial nerves have nuclei in the medulla oblongata?
VIII, IX, X, XI, and XII
(or cranial nerves 8-12)
or vestibulocochlear glossopharyngeal vagus accessory hypoglossal
What is the main function of the pons?
it’s a bridge that connects different parts of the brain, including the left and right sides of the cerebellum
Where are the cerebellar peduncles found?
in the white matter of the pons
Which of the cerebellar peduncles is the largest?
middle cerebellar peduncle
What are the two regions of the pons?
ventral and dorsal
Where in the pons are the pontine nuclei found? What is their function?
ventral region
coordination/efficiency of voluntary movement
What is contained in the dorsal region of the pons?
ascending and descending tracts
nuclei of some cranial nerves
What can be found in the grey matter of the pons?
the pontine respiratory group (nuclei)
the nuclei of the trigeminal (V), abducens (VI), facial (VII) and vestibulocochlear (VIII) nerves
or cranial nerves 5-8
Where is the cerebral aqueduct?
in the midbrain
What are the two parts of the midbrain?
the anterior tegmentum
the posterior tectum
Where are the cerebral peduncles found?
anterior midbrain
What is the function of the mammillary bodies adjacent to the tegmentum? What brain structure are they part of?
relay stations for olfaction reflexes
hypothalamus
The tectum is composed of what four rounded grey matter elevations?
2x superior colliculi
2x inferior colliculi
What is the function of the superior colliculi?
visual activity reflex center
What is the function of the inferior colliculi?
reflex centers for startle reflex, part of auditory pathway
The left and right substantia nigra are found in which part of the brain?
midbrain
The left and right red nuclei, as well as the periaqueductal gray matter, are found where?
midbrain
The nuclei for the oculomotor and trochlear nerves are found where?
in the gray matter of the midbrain
The ascending portion of the reticular formation is called the…
reticular activating system (RAS)
What sensory information can activate the RAS?
visual auditory pain touch pressure proprioception
What sensory information does the RAS not receive?
smell
What 4 things does the descending portion of the reticular formation regulate?
heart rate
blood pressure
respiratory rate
muscle tone
The cerebellum is only 1/10th of the mass of the brain, but it contains ____ of the neurons in the brain
almost half
What are three examples of when the RAS is active?
- during arousal (awakening from sleep)
- maintaining attention
- preventing sensory overload by filtering insignificant info
What does inactivation of the RAS produce?
sleep
What are the two cerebellar hemispheres separated by?
vermis
What type of matter is on the surface and in the core of the cerebellum?
gray
What are in the core of the cerebellum?
cerebellar nuclei
Name the 3 pairs of cerebellar peduncles:
- superior cerebellar peduncle (axons to red nuclei and thalamus)
- middle cerebellar peduncle (largest)
- inferior cerebellar peduncle
Where does the middle cerebellar peduncle contain axons from?
pontine nuclei
What 4 areas does the inferior cerebellar peduncle contain axons from?
- spinocerebellar tracts
- from and to vestibular apparatus
- from inferior olivary nucleus
- to the reticular formation
What are the 4 functions of the cerebellum?
- monitoring INTENTION for movement
- monitoring actual movements
- comparing intention with actual movement
- correcting discrepancies
What are the 3 portions of the diencephalon and what ventricle is it located?
Portions: thalamus, hypothalamus, epithalamus
Located in the third ventricle
What structure composes 80% of the diencephalon?
thalamus
What does an interthalamic adhesion do?
connects both thalami
What is the thalamus a major relay station for?
most sensory impulses from the spinal cord and brain stem to the cerebral cortex.
What is the major role of the hypothalamus?
major regulator of homeostasis (monitors sugar levels, hormone concentration and temp)
Where does the hypothalamus receive impulses from?
Somatic and visceral receptors, and from vision, taste and smell
What gland is the hypothalamus connected to?
hypophysis (pituitary) gland
Where is the epithalamus located?
superior and posterior to thalamus
What 2 things does the epithalamus consist of?
- pineal gland
2. habenular nuclei (anterior to pineal gland)
What does the pineal gland secrete?
melatonin
What area is involved in emotional responses to olfaction?
habenular nuclei
The subarachnoid space and the fourth ventricle are connected via…
the median and 2 lateral apertures
The three gray matter structures at the core of the cerebrum are together called the ____ and individually they are:
basal ganglia
globus pallidus
putamen
caudate nucleus
What is the role of the basal nuclei?
help initiate and terminate movement regulate muscle tone regulate emotional behaviour control subconscious muscle contraction help initiate & terminate attention/memory/planning
The descending portion of the RAS helps regulate what 4 things?
muscle tone
HR
BP
respiratory rate
The white matter in the core of the cerebellum is called the…
arbor vitae
The pineal gland protrudes from…
the third ventricle
The primary somatosensory area of the cerebral cortex is just posterior to the…
primary motor area
The primary visual area/visual association area is in the…
occipital cortex
The association tracts of the cerebrum are found between…
the gyri
The commissural tracts of the cerebrum have what role? What are the 3?
connect the cerebral hemispheres
corpus callosum
anterior commissure
posterior commissure
What are the 3 types of tracts found in the cerebral white matter?
association
commissural
projection
Why is aphasia less likely after a stroke in women?
there is less hemispheric lateralization
Alpha brain waves are associated with what states?
normal/awake/resting/eyes closed
Delta brain waves are associated with what states?
deep sleep in adults
if in awake adults: brain damage
normal in awake infants
Theta brain waves in adults are associated with what states?
emotional stress/brain disorder
