Brainstem and Cerebellum Flashcards
Parts of Brainstem
Midbrain
Pons
Medulla Oblongata
Brainstem Function
Relay center for sensory input and motor output
Also responsible for many basic reflex actions such as vomiting, breathing, HR
Cerebellum Function
Like a small light bulb; high motor and sensory functions
Pyramids
Bilateral ridges on anterior side. Contains motor axons and most of these axons decussate (cross). Each side of brain controls opposite side of body
Autonomic Nervous System Centers (ANSC)
Cardiac Center
Vasomotor Center
Respiratory Center
Cardiac Center
Regulates heart rate
Vasomotor Center
Constricts and dilates arterioles
Respiratory Center
Regulates breathing rate
Medulla Oblongata Location
Becomes apart of the fourth ventricle
Pons
Chiefly composed of groups of axons (nerve fiber tracts)
Contains Respiratory Center and is also the Superior Part of Fourth Ventricle
Midbrain
Superior Part of Brainstem
Midbrain Components
Tectal Plate
Cerebral Penduncles
Cerebral Aqueduct
Tectal Plate
On posteior side of midbrain
Divided into superior and inferior calliculi. Relay stations in the processing pathway of visual and auditory sensations
Superior Colliculi
(2) Visual Reflex Centers.
Coordinates head and body movement to sudden image
Inferior Collicul
(2) Auditory Reflex Centers
Coordinate head and eye movement to sudden sound
Cerebral Peduncles
Groups of axons (nerve fiber tracts) on anterior side of midbrain
Conduct nerve impulses between cerebrum and brainstem
Cerebral Aqueduct
Connects fourth ventricle to third ventricle. Partly in pons and medulla obiongata.
Cerebellum
Right and left cerebellar hemispheres
Cerebellar Peduncles Components
Inferior Cerebellar Peduncles
Middle Cerebellar Peduncles
Superior Cerebellar Peduncles
Cerebellar Peduncles Functions
Coordinate and fine tunes skeletal muscle movement.
Cerebellum makes movement pretty, cerebellum initiates movement
Maintains balance and posture
Inferior Cerebellar Peduncles
Connects medulla oblongata to cerebellum
Middle Cerebellar Peduncles
Connects pons to cerebellum
Superior Cerebellar Peduncles
Connects midbrain to cerebellum
Layers in Brain from Deepest to Superficial
Pia Mater -> Arachnoid Mater -> Dura Mater
Inner and Outer Meningeal Layer
Surround the dural venous sinus. These are large veins that drain blood to the brain
Cerebrospinal Fliud
Provides buoyancy for brain and spinal cord. Maintains CNS Chemical Environment.
CSF Production
Made in the ventricles of the brain.
Specifically the Choroid Plexus ( = Blood Capillaries + Ependymal Cells) in ventricles
Ventricular System Components
Left and Right Lateral Ventricles
Third Ventricle
Cerebral Aquefuct
Fourth Ventricle
Left and Right Lateral Ventricles:
Found in each cerebral hemisphere
Third Ventricle Function
Space in diencephalon
Connects to each lateral ventrricle via an interventricular foramen (Goes from lateral to erebral aqueduct)
Cerebral Aqueduct Location
In Brain
Fourth Ventricle Location
In pons and medulla oblongata
CSF Circulation Process Simple (1)
CSF produced by choroid plexus in ventricles
CSF Circulation Process Simple (2)
CSF flows from third ventricle, to cerebral aqueduct, to fourth ventricle
CSF Circulation Process Simple (3)
CSF leaves fourth ventricle and enters subarachnoid space
CSF Circulation Process Simple (4)
CSF circulates in subarachnoid space
CSF Circulation Process Simple (5)
Excess CSF removed from subarachnoid space by arachnoid villi
Arachnoid Villi Definition
Extensions of arachnoid mater that project into dural venous sinus
CSF Circulation Process Complex (1)
CSF is produced in the ventricles by the choroid plexus
CSF Circulation Process Complex (2)
CSF flows from the lateral ventricles and third ventricle through the cerebral aqueduct into the fourth ventricle.
CSF Circulation Process Complex (3)
Most of the CSF in the fourth ventricle flows into the subarachnoid space by passing through openings in the roof of the fourth ventricle. These ventricular openings are the paired lateral apertures and the single median aperture. CSF also fills the central canal of the spinal cord.
CSF Circulation Process Complex (4)
As it travels through the subarachnoid space, CSF removes waste products and provides buoyancy for the brain and spinal cord.
CSF Circulation Process Complex (5)
As CSF accumulates within the subarachnoid space, it exerts pressure within the arachnoid villi. This pressure exceeds the pressure of blood in the venous sinuses. Thus, the arachnoid villi extending into the dural venous sinuses provide a conduit for a one-way flow of excess CSF to be returned into the blood within the dural venous sinuses.
What happens is CSF production begins to exceed its removal or drainage at the arachnoid villi?
Hydrocephalus ‘Water on the Brain”
Fluid builds up in ventricles and brain becomes distorted because it is being compressed.
