brainstem Flashcards
1
Q
what are the parts of the brainstem
A
- mid brain
- pons
- medulla
2
Q
what does the brainstem originate from
A
- the midbrain and parts of the hindbrain
- it is originally the neural tube which then develops into the hindbrain
3
Q
what are the functions of the brainstem
A
- conduction pathway for the sensory, motor and autonomic information
- cranial nerve functions: accommodation, corneal, vestibulocochlear
- autonomic circuits
- reflex circuitry: breathing, vasomotor, swallowing, coughing, salivation, vomiting
- balance
- sensory filter
- chemoreceptors
- movement
- pain modulation
4
Q
how does the motor pathway work
A
- the corticospinal track help you make the body move (any damage here leads to paralysis)
- the corticobulbar is cranial nerves 3,4,5,6,7,9,10,11,12 - movement can occur due to these nerves
5
Q
how does the sensory pathway work
A
- it detects sensations through the peripheries and travels the through the pain pathway up the spinal column and to the brain
6
Q
what does the spinothalamic pathway detect
A
- pain
- crude touch
- temperature
7
Q
what does the dorsal column detect
A
- fine touch
- vibration
- proprioception
8
Q
how does the ventilation feedback regulation work
A
- decrease in pO2, increase pCO2 and decrease pH in plasma
- activation of peripheral chemoreceptors
- increase frequency of AP in afferent neurones
- medullary respiratory centre - causes an activation of VRG + DRG
- increase AP firing frequency along somatic nerves to skeletal muscles of ventilation
- primary and secondary respiratory muscles
- causes an increase in depth of breathing which increase the ventilation rate
9
Q
how does the baroreflex control the heart and vessels?
A
- when there is an increase in blood pressure this then cause an increase of them firing
- an increase in baroreceptor firing causes an increase of nucleus tractus solitarius firing (NTS)
- increase in NTS causes vasodilation, causing a decrease in HR, then decreasing the force of contraction
10
Q
what does an increase of NTS firing cause
A
- decrease cardio-acceleratory area
- decrease vasomotor area
- increase cardioinhibitory area
11
Q
how do vital reflexes control breathing
A
- through rhythmic control and chemoreceptor reflexes
- an increase in CO2, pH and O2 triggers the brain to breath more
12
Q
how does CO2 control breathing
A
- high CO2 is a potent driver of respiration so any increase control the chemoreceptor reflex
- this also occurs with a low pH
- if sats are below 60 the brainstem triggers an increase in resp rate
13
Q
what structures are involved in the control of breathing
A
- ventral respiratory group neurones
- dorsal respiratory group
- apneustic centre
- pneumotaxic centre
14
Q
how is the ventral respiration group involved in breathing
A
- located in the medulla
- where the pacemaker cells are for breathing
15
Q
how is the dorsal respiratory group involved in breathing
A
- stimulates inspiration
- this is done through electrode stimulation makes you want to inspire