Neurotransmitters & Seizures Patho Flashcards
Receptors are _____
proteins
what do receptors match?
the size & shape of a neurotransmitter
how are receptors named?
according to the transmitter they bind with
transmitters are either _______ or _________ depending on what?
inhibitory or excitatory
depending on the type of receptor it binds to
Is dopamine inhibitory or excitatory?
inhibitory
is ACH inhibitory or excitatory?
Can be either excitatory or inhibitory – depends on
neurons secreting it.
is serotonin inhibitory or excitatory?
inhibitory
is norepinephrine inhibitory or excitatory?
excitatory
is GABA inhibitory or excitatory?
inhibitory
where do neurotransmitters work?
at the synaptic cleft where they either inhibit or excite the neurons
where is acetylcholine (Ach) found? (3)
CNS
PNS
ANS
When is Acetylcholine excitatory?
in the parasympathetic nervous system (PNS) at neuromuscular junctions
When is Acetylcholine inhibitory?
in the autonomic nervous system (ANS) and it slows heart rate
what neurotransmitter derived from tryptophan?
Serotonin (5-hydroxytrptamine)
where is Serotonin (5-hydroxytrptamine) primarily found? (3)
GI tract
platelets
brainstem
Serotonin (5-hydroxytrptamine) contributes to a feeling of?
well being
where is dopamine located?
mainly in substantia nigra of midbrain/basal ganglia region
list the functions of dopamine (8)
- behavior and cognition
- voluntary motor movement
- motivation
- punishment and reward
- attention
- working memory
- learning
- involved in many neuropsychiatric and voluntary motor movement disorders
What neurotransmitter is involved in tourettes?
dopamine
What is the chief inhibitory transmitter in the CNS?
Gamma amino butyric acid (GABA)
what effects does Gamma amino butyric acid (GABA) have on brain? (3)
- relaxing
- anti-anxiety
- anticonvulsant
what effect does Gamma amino butyric acid (GABA) have on muscles?
inhibitory effect: decrease muscle spasms and improved tone
What neurotransmitter is involved in social phobia?
dopamine
what is an excitatory neurotransmitter in brain and stress hormone within the endocrine system?
norepinephrine
what is a major mediator of excitatory signal?
Glutamate
what plays a role in fight or fight response?
norepinephrine
What neurotransmitter is involved in ADHD?
dopamine
What is glutamate involved in? (3)
- cognition
- memory
- learning
what do neurons use to conduct impulses?
action potentials
What neurotransmitter is involved in drug and alcohol dependence?
dopamine
what are action potentials?
Abrupt changes in membrane potential which permit nerve signals to be transmitted from the cell body down the axon.
What neurotransmitter is involved in parkinsons?
dopamine
When action potentials are stimulated, what ions move across axon membrane? (3)
sodium
potassium
calcium
what are the three phases of nerve conduction?
- Depolarization: neuron receives a signal and becomes positively charged, which sends message down the nerve
- Re-polarization: the neuron returns to negative value (usually they are polarized in negatively charged state)
- Resting Period: then there is a resting period
how can impulses lead to seizures?
Impulses that do not maintain a systematic order
(excitatory, inhibitory, and rest phase become
irregular and chaotic) can lead to seizures
What are seizures?
A single episode of abnormal electrical discharge from cortical neurons that results in an abrupt and temporary altered state
what is epilepsy?
A group of syndromes characterized by unprovoked, recurrent seizures
what is status epilepticus?
Continuous seizure activity for more than 5 minutes or 2 or more sequential seizures that occur without full recovery of consciousness between attacks.
list the common causes of seizures? (14)
- Trauma
- ETOH withdrawal
- Illicit drug use
- Brain tumor
- Congenital malformations
- Stroke
- Metabolic disorders
- Uremia
- electrolyte imbalance
- Alzheimer’s disease
- Neurodegenerative disease
- Idiopathic
- flashing lights
- stress
list the common causes of epilepsy (5)
- genetic causes
- head trauma
- medical disorders
- prenatal injury
- developmental disorders
> 30 mutated genes have been found in families with _______
epilepsy
Genetic causes of epilepsy may occur in genes coding for different things. what are examples? (3)
ion channels
neuronal receptors
transcription factors
many pediatric epilepsies are associated with what?
random gene mutation for the first time (de novo)
what is true for about half of seizure disorders?
there are no genetic or structural abnormalities present
what medical disorders are common causes of epilepsy? (3)
dementia
meningitis
encephalitis
what developmental disorders are common causes of epilepsy? (2)
autism
down syndrome
Pathophysiology of seizues:
1. Messages from the body are carried by the ______ of the brain through discharges of _________ ______
2. These impulses occur in _____
3. During periods of unwanted discharges, parts of the body may ___ ________
- neurons; electrochemical energy
- bursts
- act erratically
For an actual seizure to occur…
1. ________ neurons
2. increase in _______ ________ activity
3. reduction in activity of ______ _______ _____ projection
- excitable
- excitatory glutaminergic
- normal inhibitory GABA
What seizures are classified as focal or partial? (2)
simple partial
complex partial
what seizures are classified as generalized? (4)
Absence (Petit Mal)
Tonic-Clonic (Grand Mal)
Atonic/Akinetic (Drop Attacks)
Status Epilepticus
a focal seizure starts and…?
may remain in 1 hemisphere
focal seizures have high-frequency bursts of _____ _______ and __________
action potentials & hypersynchronization
focal seizures may have _____, _______, _______ symptoms and automatisms
motor, sensory, autonomic
the autonomic sx from focal seizures are due to what?
stimulation of autonomic nervous system
what are the autonomic sx of a focal seizure? (4)
pallor
sweating
pupillary dilation
epigastric sensation
what are automatisms?
Coordinated involuntary movements occurring during state if impaired consciousness either during or after seizure.
are pts aware or unaware during automatisms?
unaware
automatisms are often associated with?
temporal lobe seizures
what are the types of focal/partial seizures?
Focal with retained awareness
Focal with altered awareness
partial seizure
in a Focal seizure with retained awareness, there is no impairment of ?
consciousness
in a Focal seizure with retained awareness, there may be? (2)
may have movement of body parts
may experience an aura
focal seizures with retained awareness are similar to what?
partial seizures
in a Focal seizure with altered awareness, there is impairment of?
consciousness
in a Focal seizure with altered awareness, it spreads to?
both hemispheres
where does a partial seizure begin?
in part of one hemisphere (typically in the temporal or frontal lobe)
partial seizures may be….?
simple or complex
Generalized seizures start in 1 hemisphere and?
spreads with involvement of both hemispheres
true or false: generalized seizures may have motor and nonmotor sx
true
what seizures always affect both hemispheres of brain?
generalized
generalized seizures cause impairment of?
consciousness
what are tonic-clonic seizures?
AKA grand mal
Begin with rigid violent contractions
(tonic) followed by repetitive clonic activity of all
extremities; body stiffness and relaxation
what are tonic seizures?
Muscle stiffness, dilation of pupils,
altered respirations
Usually lasts less than a minute
what are absence seizures?
Short episodes of staring and loss of consciousness 10 seconds
what are myoclonic seizures?
Bilateral jerking of muscles.
No loss of consciousness
what are atonic seizures?
Sudden loss of muscle tone;
“drop to ground”
Calcium going in during a cells resting state facilitates what?
development of an action potential
glutamate receptor has how many potential binding sites?
5
