What are the components of the brainstem?
Where is the brainstem located?
Inferior to thalamus
Superior to spinal cord
Posterior to sphenoid sinus
Anterior to cerbellum
Is the thalamus part of the brainstem?
Is the basal ganglia part of the brainstem?
What part of the brain are the 2 cerberal peduncles?
What is the pons?
A bridge between the left side and the right side of the cerbellum
Where do transverse nerve fibers between cerebella go?
Where do longitudinal fibers (moving towards the spinal cord) from the cerebrum go?
What sits on the depression of the pons of the medulla?
The basilar artery.
What are the 2 legs of the medulla oblongata called?
What is the smaller almond shaped thing next to the pyramids of the medulla oblongata called?
What is the sulcus of the medulla oblongata called?
Anterior median sulcus
What cranial nerve goes through spinal cord?
Spinal accessory nerve
What are the 4 round structures in the posterior midbrain?
Superior and inferior colliculi
Quadrigeminal plate or tectum of midbrain
Where does the trochlear nerve arise from?
Directly below the inferior colliculi
Where is the pineal gland?
On the posterior aspect
Which peduncles are seen in the anterior view if midbrain?
Which peduncles are seen in the posterior view of midbrain?
What is located in the posterior view of the brain in the location opposite of the pons?
The rhomboid fossa which is the floor of the 4th ventricle of our brain.
What starts at the tip of the caudal part of the rhomboid fossa?
The medulla oblongata
What are the legs of the medulla located on the posterior end?
Fasciculus gracilis and fasciculus cuneatus
No need to remember for this semester
What are the 12 cranial nerves?
I) olfactory (Smell)
II) optic (Retina, vision)
III) oculomotor (Eye muscles [medial, superior, inferior, superior oblique muscles and levator palpibae superiorus]
VI Abducens [lateral rectus muscle (abducts the eye)]
VII) Facial (muscles of facial expression, watering of eyes and nose)
VIII) Vestibulocochlear (hearing and balance)
IX) Glossopharyngeal (taste to posterior 1/3rd of tongue and facial does anterior 2/3rds)
X) Vagus (responsible for gag reflex due to closing of the palatoglossus muscle which is innervated by vagus)
XI) Spinal accessory (originates in spinal cord and then goes up to brainstem through foramen magnum)
XII) Hypoglossal (motor to intrinsic and extrinsic muscles of tongue)
What does the vestibulocochlear nerve bind to that maintains balance?
Where does hypoglossus originate?
At the medulla oblongata at the level below the tongue
Where do the cranial nerves originate?
Midbrain: III, IV
Pons: V, VI, VII, VIII(Little bit of it)
Medulla oblongata (IX, X, XII)
What does spinal accessory do?
Elevates shoulders (trapezius muscle) and turns head (sternocleidomastoid)
What are the peduncles composed of?
The tegmentum and the basis pedunculi (base)
What does the cerebral aquaduct (the hole on top the the midbrain) do?
Transfers CSF from 3rd ventricle to 4th ventricle
Where are the nuclei for the oculomotor and trochlear nerve located?
right next to the aquaduct of the midbrain. These nuclei are called periaquaduct nuclei.
What tract starts at the red nuclei?
The rubrospinal tract
What is the substantia niagra?
Brown coloured matter between the tegmentum and the basis peduncluli.
Why is the substantia niagra brown?
It contains melanin. This site produces dopamine. This is missing in people with parkinson’s disease
Where is the cerebral aqueduct located?
just above the superior colliculi between the periaqueductal nuclei
What does the cerebral aqueduct get surrounded by?
Periaqueductal grey matter
What happens if the cerebral aqueduct is blocked?
Hydrocephalus, resulting in more pressure and resulting in damage to brain and protrusion of eyes and rupture of arteries and veins of the eyes.
What do the basis pedunculi of the brainstem contain?
Descending cortical efferent fibers projecting from cortex to internal capsule to midbrain
Medial portion contains all the corticospinal (UPM to PNS) and corticobulbar (UPM to CN) tracts
Lateral portion contains corticopontine fibers (cortex -> pontine nuclei -> cerbellum)
What does white matter contain in the basis pedunculi?
Where do longitudinal fibers in the pons travel?
Longitudinal perpendicular to the transverse fibers of the pons behind them (more anterior)
What fossa is the floor of the 4th ventricle?
The rhomboid fossa
What artery supplies the pons?
What cranial nerves arise from the pons?
CN V, VI, VII, VIII
Where does the decussation of nerves in the brain stem from the cerebrum take place?
In the medulla oblongata just below the 2 pyramids.
90% of fibers decussate here and form the lateral corticospinal tract and 10% dont decussate and form anterior corticospinal tract
Which structures form the 2 legs of the medulla oblongata anteriorly and posteriorly?
Cuneuatus and gracillus fasoculi posteriorly
What are the olives made up of in the medulla oblongata?
The inferior olivary nuclei.
What colour are the olivary nuclei in life?
What does the inferior olivar nucleus do?
It is involved in balance and control of movement.
Receives afferents from motor and sensory cortices of cerebrum and red nucleus of midbrain.
Which tract goes to red nucleus?
The rubrospinal tract
Which cranial nerves exit the medulla oblongata?
IX X and XII (exits between pyramid and olive)
Where does CNXII exit from?
Between pyramids and olives
What happens to waste material in Nuclei (location of cell bodies and most of the metabolism of the nerves)?
They are located near ventricles which means they enter cerebrospinal fluid through the pia mater.
What does the caudal medulla contain?
The 1st order sensory neurons whose cell bodies are in Dorsal Root ganglia of spinal nerves. They ascend ipsilaterally through the cord and into the medulla.
A patient has weakness and wasting on left hand side of face and the lower body has a flexed right upper limb and spastic weakness of right lower limb he also has loss of sensation on left side of face and right side of body. What does this indicate?
A problem with the pons medulla on the left side
What is a babinski reflex and what does it indicate?
Dorsiflexion in response to stimuli on bottom of foot. This indicates problems with brain.