Chapters 14-15 Flashcards
Brainstem cont, NTs, and cerebellum
The cranial nerve nuclei are found where?
Brainstem
Many nerve tracts, including the corticospinal tract, and the pyramidal decussation, are found where?
The brainstem
What are the 4 main groups of things found in the brainstem?
1) Cranial nerve nuclei and related structures
2) Long tracts
3) Cerebellar circuitry
4) Reticular formation and related structures
Give 2 examples of long tracts found in the brainstem
1) Corticospinal tract
2) Somatosensory pathways
Give examples of things controlled by the “reticular formation and associated structures” category of brainstem structures
Brainstem nuclei and neurons that coordinate many of our vital functions such as :
1) Ex/motor control systems
2) Posture
3) Respiration
4) Cough, hiccup, sneeze, shiver
5) N/v
6) Autonomic control including HR and BP
1) What is the Medial Longitudinal Fasciculus (MLF)?
2) Fibers from what 2 nuclei ascend here?
1) Heavily myelinated pathway connecting vestibular nuclei with nuclei involved with extraocular movements.
2) Medial and superior vestibular nuclei
Fibers from the medial and superior vestibular nuclei ascend in the MLF to what 3 nuclei to mediate vestibulo-ocular reflexes?
Oculomotor (3), trochlear (4) and abducens (6) nuclei
List and describe the long tracts of the brainstem
1) Corticospinal and corticobulbar: nerves from cortex to brainstem
2) Somatosensory pathways (posterior columns): vibration, proprioception and fine touch
3) Spinothalamic tract: antero-lateral pain, temperature, and crude touch
4) Descending sympathetic pathway: runs through lateral brainstem; damage to this causes Horner’s Syndrome
What tracts are nerves that run from the cortex to the brainstem?
Corticospinal and corticobulbar
What tract is responsible for pain, temperature, and crude touch?
Spinothalamic tract (antero-lateral)
What pathway runs through lateral brainstem? What does damage to this cause?
Descending sympathetic pathway; Horner’s Syndrome
What pathways are responsible for vibration, proprioception and fine touch?
Somatosensory pathways (posterior columns)
1) What is the reticular formation?
2) What does its rostral end do?
3) What does its caudal end do?
1) Central core of nuclei that runs through the entire length of the brainstem
2) Maintain an alert conscious state.
3) Works with cranial nerve nuclei and the spinal cord to carry out motor reflex and autonomic functions
What 2 things work with the caudal end of the reticular formation?
Cranial nerve nuclei and the spinal cord
1) What is the end goal of the rostral end of the reticular formation?
2) What is the end goal of the caudal end of the reticular formation?
1) Maintain an alert conscious state.
2) Carry out motor reflex and autonomic functions
In Locked-In-Syndrome:
1) Motor function is ________
2) Sensation and cognition are ________
3) What two tracts are affected?
1) Absent
2) Intact
3) Corticospinal and corticobulbar
True or false: Locked-In-Syndrome is a type of coma
False; they’re different
1) What usually causes locked-in-syndrome?
2) Why exactly can’t they move?
1) Infarct in the ventral pons, affecting the corticospinal and corticobulbar tracts.
2) These tracts being affected means the spinal cord and cranial nerves receive no input from the cortex
Regarding locked-in-syndrome:
1) What pathways and systems are spared? What does this cause?
2) Why are eye movements spared?
3) Is it the same as a coma?
1) Sensory pathways and arousal systems in brainstem are spared, so patients are aware and able to feel, hear, and understand.
2) Their control center is in the rostral midbrain
3) No
What forms the consciousness system?
The fronto-parietal association cortex with the arousal circuits in the upper brainstem.
List the 3 processes that control the levels of consciousness and what’s involved with each
1) Alertness: normal functioning of the brainstem and arousal circuits
2) Attention: same circuits as above plus the frontoparietal association cortex
3) Awareness: a combination of multiple higher order systems from different regions of the brain into a summary of mental activity that can be remembered at a later time
1) List the 3 processes that help control the level of consciousness
2) Which of these involves a summary of mental activity that can be remembered at a later time?
1) Alertness, attention, awareness
2) Awareness
True or false: Multiple interconnected arousal systems act in parallel to maintain normal consciousness
True
Name the 5 arousal systems that maintain normal consciousness
1) Upper brainstem neurons
2) Reticular formation
3) Posterior hypothalamic neurons
4) Basal forebrain neurons
5) Neurons in the rostral and medial thalamic nuclei
What activates the 5 arousal systems that maintain normal consciousness?
Reticular formation and related structures that receive input from sensory pathways
1) What project to the reticular formation?
2) Why?
1) Numerous regions of the association cortex
2) So cognitive processes and emotions can lead to an increased level of alertness through this system.
1) What is the major excitatory neurotransmitter in the CNS?
2) What does too much of this cause?
1) Glutamate
2) Huntington’s chorea
What is referred to as “nature’s valium”? Why?
GABA; it’s inhibitory
1) Meds that increase GABA are used to treat what 3 things?
2) What 4 arousal systems does it inhibit to promote deep sleep?
1) Anxiety, seizures, muscle spasms
2) Serotonergic, noradrenergic, histaminergic, and cholinergic arousal systems.
What are the 3 primary functions of acetylcholine (Ach)?
1) Autonomic function
2) Stimulates receptors at NMJ to cause muscle contraction.
3) In CNS it helps with memory
What is Myasthenia gravis and what does it lead to?
An autoimmune Ab block Ach receptors on skeletal muscle, leading to weakness
1) What can dopamine cause?
2) What does it work on?
3) What can too much lead to?
4) What can too little lead to?
1) Feelings or pleasure, satisfaction and motivation.
2) Reward center.
3) Schizophrenia, increased energy/arousal, hallucinations
4) Parkinson’s Disease
1) What are the two main functions of norepinephrine?
2) What does increased amounts cause?
3) What does too little cause?
1) Used in sympathetic response and functions in attention, cognition and BP.
2) Aggression
3) Depression, inattention/ADD
1) What is also known as the “feel good” chemical?
2) Is it excitatory, inhibitory, or both?
1) Serotonin
2) Can have excitatory and inhibitory effects