Module 7 Flashcards
What does the brainstem connect?
Hemispheres
Diencephalon
Cerebellum
WITH THE spinal cord
What is considered the CORE of the brain?
Brainstem
What are the three divisions of the brainstem?
Midbrain (mesencephalon)
Pons (metencephalon)
Medulla (myelencephalon)
What are the roles of the brainstem?
Provides transit for ascending and descending pathways
Regulates vital functions of the body
Subserves cranial nerves functions; house CN nuclei
Describe the transit role of the brainstem
Sensory signals from SC to thalamus Motor signal from cortex to SC Connects: Cerebellum and cerebrum (superiorly) Cerebellum and SC (posteriorly)
Describe the vital functions of the brainstem
Respiration/Arterial pressure/Heart beat/Equilibrium
Determines level of activity of cerebrum
Determined arousal levels
Controls sleep/wake cycles
What type of CN does the BS house and what are their CN Functions?
Sensory nuclei of termination
Motor nuclei of origin
What are the four regions of the brainstem?
Roof (dorsal/post.) Basilar portion (ventral/ant.) Tegmentum (core/central) Ventricular cavities (midline/post.)
What are the two ways you can view the brainstem?
Ventral
Lateral
Where is the roof and what is it comprised of?
In the midbrain…
The tectum in the midbrain
Comprised of: Superior colliculi (vision) Inferior colliculi (audition)
Where is the roof at the pons level?
Cerebellum
Where is the roof in the lower pons, medulla?
Floor of the 4th ventricle
What is the basilar portion (ventral view) comprised of?
Cerebral peduncles (midbrain)
Pons (ventral)
Pyramids (medulla)
Which region is considered the core of the brainstem?
Tegmentum
Extends through the entire dorsal of the brainstem (midbrain/pons/medulla)
What does the central tegmental tract carry?
Sensory and motor pathways
Which two structures in the tegmentum are related on the BG?
Red nucleus and substantia nigra
What comprises the ventricular cavity?
Cerebral aqueduct (connect 3rd/4th ventricle)
What are the divisions of the brainstem?
External landmarks
Internal structures
What external landmarks are on the (ventral) side of the midbrain?
Cerebral peduncles
Optic tract/chiasm
What landmarks are on the (dorsal) side of the midbrain?
Corpora quadrigemina
(Superior colliculi/ inferior colliculi)
Superior/inferior brachia
(Connects colliculi with thalamus)
Superior cerebellar peduncles
What does the pons form?
Basilar part of metencephalon
What is the function of the pons?
Provides transit for ascending and descending sensory/motor pathways
Contains corticopontine fibers
Which CN nuclei are located on the pons?
V- touch and proprioception from face/head
VI- abducens (motor for eye movement
VII- facial / taste (back of tongue)
VIII- vestibulocochlear (hearing/balance
Where do the CN exit from the pons?
V- mid-pons (lateral)
VI- pons-medulla (ventral)
VII- pons-medulla (ventrolateral)
VIII- pons-medulla (ventrolateral)
What is at the lowest brainstem level/division?
Medulla
Describe the medulla
Forms the myelencephalon
Choroid plexus in floor of 4th ventricle forms the roof of the medulla
What are some external landmarks in the medulla?
Pyramids (basilar portion)
Olives (anterolateral portion)
4 CN exit from medulla
Which CN exit from the medulla?
IX
X
XI
XII
What is the function of the olives on the medulla?
Serves motor function
Input from BG/SC
Output to cerebellum
What are some internal structures within the medulla?
Ascending sensory and descending motor pathways
4th ventricle (roof)
Reticular formation
CN nuclei
Spinal sensory nuclei associated with medial lemniscus pathway
Name the nuclei of the medulla
XI X XI XII spinal nucleus of CN V (pain/temp. H/f) Solitary nucleus (taste from VII/ cough reflex from X/ gag response from IX, X)
What is unique about the reticular formation?
Phylogenetically old
Comprised of core nuclei (dispersed through tegmentum)
Divided into 3 zones
What is the purpose of the central tegmental tract and RF?
RF integrates sensory/motor inputs from spinal/cranial nerves/cerebrum/cerebellum
Organization of RF Nuclei/pathways allows it to project to ALL levels of SC/brains
Contains pain pathway/ motor pathways and ascending reticular activating system
What are the functions of the reticular formation?
Modulates awareness and controls level of alertness
Maintains brains homeostasis
Helps in regulations of body functions and behaviors
Lesions to the midbrain and diencephalon result in what?
Coma
Lesions to pontine RF result in what?
Constant wakefulness (very rare)
