Module- CNS Flashcards
Anxiety definition
refers to a state of tension, apprehension, or uneasiness that stems from the anticipation of danger - the source of which is largely unknown or unrecognized
Anxiety Disorder definition
When anxiety impairs a person’s ability to engage in normal day-to-day functions
T or F:
There are clear bounds between normal and abnormal anxiety
False
What is an anxiety disorder?
Any disorder that shares features of excessive fear and anxiety accompanied by behavioural disturbances.
They differ from one another in the types of objects or situations that induce this anxiety.
How are anxiety disorders diagnosed
- Diagnosis should only be made when the client’s behaviours symptoms cannot be better explained by another mental disorder or attributed to the physiological effects of an existing medical condition or to the adverse effects of a substance or medications
Separation Anxiety Disorder
Feelings of fear or anxiety about separation from attachment figures
Selective Mutism
Consistent failure to speak in social situations where speaking is expected
Specific Phobia
Fearful or anxious feelings about a particular situation or object
Social Anxiety Disorder
Fear, anxiety and avoidance of social interactions and situations
Panic Disorder
Intense feelings of immediate apprehension, terror, or impending doom accompanied by increased autonomic nervous system activity
Agoraphobia
A fear of open spaces; trying to escape and concerns that help might not be available
Generalized Anxiety Disorder
Anxiety symptoms are the physiology consequence of another medical condition
Substance or medication-induced anxiety disorder
Anxiety due to intoxication or withdrawal from a substance or prescribed medication
Pathophysiology of anxiety
· Norepinephrine is an excitatory neurotransmitter
· Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter
· Stimulation of the Hypothalamus-Pituitary-Adrenal (HPA) axis induces, corticotropin-releasing factor (CRF) release.
CRF release stimulates the locus ceruleus and induces norepinephrine release thereby activating the limbic system and cerebral cortex.
This generates the feelings of anxiety
What is the Cerebral Cortex
- The “thinking” or conscious portion of the brain.
- This brain region processes sensory inputs, regulates voluntary muscle action,
- is responsible for intellect, memory, learning, decision making, and other higher level brain functions
What is the Locus ceruleus
A brain stem nucleus that contains many noradrenergic neurons and has extensive projections to the limbic system, cerebral cortex and cerebellum
What is the limbic system?
An area in the middle of the brain responsible for emotional expression, learning and memory. Includes the amygdala (not shown)
What is the Hypothalamus
Responsible for unconscious responses to stress such as elevated blood pressure, respiratory rate, and dilated pupils
GABA Hypothesis
People with anxiety disorders release an excess of the excitatory neurotransmitter norepinephrine in response to normal stimuli
In combo with a deficiency in GABA release we see an exaggerated response htat is disproportioned to the threat of the activity
What is GABA? Where are thier receptors located?
· GABA serves as the major inhibitory neurotransmitter the brain and spinal cord
· Their receptors are located throughout the brain, and are associated with chloride channels
What is the effect when GABA binds to their receptor
When GABA binds to its receptor, the channel opens, allowing chloride to move into the neuron
Movement of chloride ions across the membrane hyperpolarizes the neuron
As a result, the cell membrane is less responses to excitatory neurotransmitters such as norepinephrine
role of the Reticular Activating system
Stimulation of the RAS produces increased alertness and arousal
Inhibition of the RAS results in sedation and sleep
Proper functioning of this system is vital for us being alter and sleeping when needed
What innervates the RAS, What does this cause?
The HPA axis innervates the reticular activating system.
When stimulated, the RAS activates the cerebral cortex resulting in increased alertness and arousal
Two results of the Activation of the hypothalamus
- Increased limbic activity thereby producing an increased fear and anxiety response
- Increased reticular activating system activity, which results in increased alertness and an interrupted sleep pattern