Brainstem Flashcards
Reticular Formation
- activating & inhibiting system
- The reticular activating system is the primary center for controlling vital functions of the cardiovascular and reparatory systems
- Regulates consciousness
- Regulate motivation
- Sleep wake cycle
- Attend to sensory stimuli, but can also inhibit (so can go to sleep)
- Alzheimer’s, ADD, sensory modulation
Tegmental Structures
- Red nucleus
- Substantia nigra
Red nucleus
- A highly vascularized nucleus
- Receives information for cortex, basal ganglia, and diencephalon and cerebellum
- Communicates through the superior peduncle
- Sends through the rubrospinal tract to the spinal cord
- Damage to this nucleus leads to cerebellar ataxia
Substantia nigra
- The largest nuclei in the region of the tegmentum and crus cerebri
- Connects with the cortex, hypothalamus, basal ganglia, and spinal cord
- Functionally involved in muscle tone
Wallenberg Syndrome
-A vascular disorder of the lateral medulla
Involve the posterior inferior cerebellar artery (PICA)
-Ipsilateral to the lesion:
-Dysphagia
-Nucleus ambiguus involvement
-Loss of gag reflex, ipsilateral paralysis of
the laryngial, pharyngeal and palat
-Vertigo nausea, vomiting, & Nystagmus
-Vestibular nuclei involvement
-Nystagmus, nausia, vomiting, & vertigo
-Ataxia
-Inferior cerebellar peduncle
-Horner’s syndrome
-Ptosis, slightly elivate pupil and lip
-Decreased sweating
-Hypothalamus & sympathetic
neuron involvement
Contralateral to the lesion:
- Decreases pain and temperature
- Anterospinothalamic tract involvement
Medial Medulla Syndrome
Vascular occlusion of anterior spinal artery
Ipsilateral to the lesion:
- Paralysis and atrophy of the tongue
- Hypoglossal nucleus involvement
Contralateral to the lesion:
- Paresis of the upper and lower extremities
- Corticospinal tract involvement
- Loss of tactile, proprioception, and vibration senses
- Medial lemniscus tract involvement
Pontine Tumors
Astrocytoma
Ipsilateral cranial nerve paralysis Facial weakness Bilateral eye weakness Nystagmus Weakness of the jaw Impaired hearing Contralateral hemiparesis of the trunk and limbs
Pontine Infarct
The pons is supplied by the basilar artery and the anterior, inferior, and superior cerebellar arteries
Facial paralysis on the side of the lesion
Lower motor neuron signs on the opposite side of the lesion
Limb paralysis
Ocular involvement
Pinpoint pupil
Locked in syndrome
- The media confuses lock in syndrome with vegetative state
- Results from bilateral destruction of pons
- Damage to the reticular activating system
- May appear comatose however consciousness is intact
- Paralysis in all four extremities
- Eye movements are available for communication
Decerebrate Rigidity
- Results from lesions to the upper portion of the brain stem involving the red nucleus
- This term adds to the confusion about spasticity
- The rigidity is most evident when presented with noxious stimuli on bony prominences
- Seen initially following traumatic injury during the comatose state
- Posturing is often evident and important treatment focus for therapists
Upper extremity posturing
- Rigid extension
- Internal rotation of the shoulders
- Extension of the elbows
- Hands pronated
- Fingers flexed at the interphalangeal joint
- Fingers extended at the MCP joint
Acetylcholine (Ach)
- In CNS regulating ANS
- In PNS facilitate action at neuromuscular junction
- Too much = dyskinesia (involuntary muscle contractions)
- Too little = paralysis
Dopamine (DA)
-Affects motor system, cognition and motivation
-Too little in substantia nigra cause Parkinson’s Disease
-Paucity of movement, festinating gait,
masked face
-Too much associated with Schizophrenia
-Hallucinations, delusions, disorganized
thinking, and paucity of thought
-Phenothiazines (parkinson symptoms) new drugs don’t have this problem
-Associated with addiction
-High from action on amygdala leading to decreased natural production leading to craving
Serotonin (5-HT)
- 14 kinds of serotonin
- Associated with sleep, emotional control, equanimity, pain regulation & carbohydrate binging
- Too little = depression and suicidal ideation
- SSRI (selective serotonin reuptake inhibitors)
- Abnormalities in serotonin system associated with anger, irritability, and depression
Effects of imbalances in neurotransmitters
Mental Illness
-Depression (serotonin, norepinephrine)
-Schizophrenia (Dopamine)
Wakefulness/Consciousness levels
-Norepinephrine, dopamine, acetylcoline,
histamine, glutamate, serotonin
Cognitive Processes
-Gaba, glutamate
Motor Activity
-Acetylcholine, dopamine
Seizure Disorders
-Gaba, glutamate
