Brainstem Flashcards
What does the brainstem consist of?
the midbrain, pons and medulla
where is the brainstem located?
It is positioned between the forebrain and the spinal cord, and it connected to the cerebellum dorsally
How many cranial nerves are associated with the brainstem?
10 pairs
What does the midbrain consist of?
cerebral peduncles, substantia nigra, the red nucleus. cerebral aqueduct and mammilary bodies
what is the role of the cerebral peduncles?
connect one major brain region to another
What cranial nerves are associated with the midbrain?
III cranial nerves anteriorly
IV cranial nerves posteriorly
What does the superior cerebellar peduncle connect to?
the midbrain
what does the middle cerebellar peduncle connect to?
the pons
what does the inferior cerebellar peduncle connect to?
the medulla
The colliculi
these are major axonal tracts connecting the brain to the brainstem.
there is the superior and inferior colliculi
superior colliculi
are incharge of visual relay and reflex centres:
- receives inputs from the visual cortex and projects to vision-related areas in the cortex
- concerned with the detection of movement of objects in the visual field
- relay information to neurons innervating the muscles that control eye movement
inferior colliculi
take part in auditory relay and reflex nuclei:
- responsible for relaying auditory information from hearing receptors of the ear to sensory cortex
- acts in reflexive response to sound
Where is the substantia nigra located?
deep to the cerebral peduncle
Substantia nigra
contains melanin pigment and if functionally linked to the basal nuclei/ganglia.
what are the regions of the substantia nigra?
Pars compacta (SNpc) Pars reticulata (SNpr) - gives inhibitory input to the thalamus
red nucleus
- lies deep to the substantia nigra.
- it has a rich blood supply and contains iron pigment.
- it is a relay nucleus in some descending motor pathways
Pons
composed of conduction tracts - both ascending and descending. it is composed of pontine nuclei
what cranial nerves is the pons associated with?
V Trigeminal cranial nerves
VI abducens cranial nerves
VII facial cranial nerve
VIII vestibulocochlear cranial nerve
What areas is the pons associated with?
the 4th ventricle and the middle cerebellar peduncle
Medulla
has a role in maintaining body homeostasis.
what centers are there in the medulla?
cardiovascular centres
respiratory centres
reflex centres
cardiovascular centres
the cardiac centre adjusts rate and force of heartbeat to meet the body needs, and the vasomotor centre adjusts blood vessel diameter to regulate blood pressure
respiratory centres
control rate and depth of breathing
reflex centres
controls activities such as coughing, sneezing, gagging, swallowing, vomiting and sweating
what does the medulla consist of?
pyramids, olives, cranial nerves, 4th ventricle, inferior cerebellar peduncle, fasciculus gracilis, fasciculus cuneatus
Pyramids
are formed by the large pyramidal tracts descending from the motor cortex
olives
contain the inferior olivary nuclei, which relay sensory information to the cerebellum
which cranial nerves are associated with the medulla?
IX glossopharyngeal
X vagus nerve
XI accessory
XII hypoglossal
fasciculus gracilis
medial tract which sends sensory information from the lower limb
fasciculus cuneatus
lateral tract which sends sensory information from the upper limb
