The brainstem Flashcards
what does the brainstem connect?
forebrain and spinal cord
What are the neurones in the brainstem involved in?
in cardiovascular and respiratory control
what is important in the brainstem?
the cranial nerves coming out of it
what is the fourth ventricle?
where the spinal fluid is made and maintains the neural tissue alive
what are the brain structures derived from?
from 3 primary vesicles of the early neural tube early in development
when do the rostral and caudal ends of the neural tube close
days 21-24
what is differentiation?
developmental process by which structures become more complex and specialised
what does the midbrain differentiates into?
tectum and tegmentum
what does the rostral hindbrain differentiates into?
cerebellum and pons
what does the caudal hindbrain differentiates into?
medulla
what information does the axons in the midbrain carry?
information from forebrain to spinal cord and vice versa
in what functions are the neurones in the midbrain involved?
- superior colliculus
- inferior colliculus
- cell groups involved in voluntary movements
- periaqueductal gray
what is superior colliculus?
receives input from eye, controls eye movements
what is the inferior colliculus?
receives input from ear, relays auditory information to thalamus
what group of cells are involved in voluntary movements?
substantia nigra and red nucleus
what is periaqueductal grey?
important in control of somatic pain sensations
what axons does the pons contain?
axons carrying information from forebrain to spinal cord and vice versa
what does the pons relay?
relays information from cerebral cortex to cerebellum
why does the pons bulge out from ventral surface?
to accommodate circuitry
what are the neurones in the pons involved in?
- reticular formation - sleep and wakefulness, body posture
2. pontine nuclei - relays info to cerebellum for motor control
where do axons that do not terminate in pons enter?
medullary pyramids
what are medullary pyramids?
corticospinal tract fibres involved in voluntary movements
what does the medulla receive?
sensory information: auditory, touch taste
what does the medulla relay?
relays touch and taste information to thalamus
what roles does the medulla have?
respiratory control, cardiovascular control and temperature control
what does the inferior olive do?
motor control
what does it mean that some cranial nerves are sensory?
they carry information from the environment to the nervous system
e.g. olfactory (sensation of smell); optic (sensation of vision)
what does it mean that some cranial nerves are motor?
they carry information out of the CNS, control the body
e.g. eye movements
what do cranial nerves that are sensory and motor control?
parasympathetic control of heart, lungs and abdominal organs; throat and neck movements, tongue movements
How many cranial nerves are there?
12
what are nuclei?
Clusters of neurones
how does the brainstem have the cardiovascular control?
brainstem receives sensory information form heart
brainstem sends information to heart to regulate heart rate and blood pressure
what is the brainstem’s respiratory control?
brainstem receives sensory information from lung and chest wall
brainstem receives information on blood pH
brainstem sends information to respiratory muscles to control breathing
what surrounds the brainstem?
major blood vessels that supply it
what is brainstem death?
when a person no longer has any activity in their brainstem - permanent loss of consciousness and the capacity to breathe
is it possible to keep someone alive after brainstem death?
yes - by keeping the person on ventilator which allows body and heart to be artificially oxygenated
is brainstem death permanent?
Yes
why does brainstem death occur?
when blood and/or oxygen supply to the brain is stopped: cardiac arrest; heart attack; blood clot; head injury; brain tumour
how is brainstem confirmed?
if the patient fails to respond all of the clinical tests
Why can limbs and upper torso move after brain stem death is diagnosed?
these movements are spinal reflexes generated by spinal cord
what is ondine’s curse?
patients suffer form respiratory arrest during sleep
- can volitionally control breathing
- do not have automatic control breathing
how is ondine’s curse acquired?
congenital or after injury or trauma to the brainstem
what is locked in syndrome?
patients have no voluntary motor control apart from the ability to perform eye movements
what causes the locked in syndrome?
a result of bilateral lesion in the ventral pons damaging the corticospinal and corticobulbar tracts
what indicates that the limbic system is intact in locked in syndrome?
emotions (crying, anxiety and laughing) modulate resting breathing pattern- limbic system is separate form volitional control
what is the brainstem consisted of?
midbrain, pons and medulla
what is the name given to the cluster of brainstem neurones that control regular breathing patterns?
Prebötzinger complex
