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85 Cards in this Set
- Front
- Back
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What are the layers of the cornea? How do corneal cells get oxygen?
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Epithelium, Bowman's layer, Stroma, Descemet's membrane, Endothelium
From atmosphere (and a little from aqeuous humor) |
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What makes the cornea transparent? (2)
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1. Perfect collagen I arrangement - spacing is < 0.5λ
2. No circulation - soluble VEGF receptor (sFLT-1) |
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Describe accomodation.
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Zonules tense when ciliary muscle relaxed = flattened lens for distance vision
CM contracts = relaxed zonules = rounded lens for close vision Controlled by PSNS - stimulated by pilocarpine, inhibited by atropine |
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What is the mechanism of presbyopia?
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Stiffening of the lens
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What is a cataract?
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Lens becomes opaque - requires replacement
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Describe the composition of the lens.
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66% water, 33% protein (crystallins, β > α > γ - "BAG")
Epithelial cells at equator divide and form <b>lens fiber cells</b> as lens grows *Absorbs UV radiation |
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Describe the flow of aqueous humor.
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Ciliary epithelium →
Posterior chamber → Anterior chamber → Conventional: Trabecular meshwork → Canal of Schlemm → episcleral veins Uveoscleral: Iris root → anterior ciliary m. → suprachoroidal space → sclera |
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How is aqueous humor produced?
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Pigmented/non-pigmented epithelial cells of ciliary epithelium linked by gap junctions
Pump ions (Na, Cl, HCO3, ascorbic acid) and water follows *β-antagonists (timolol): block Na/K/2Cl ? *CA inhibitors *α2-adrenergic agonists: ?? |
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What is the problem in glaucoma?
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Decrease in outflow facility = increase intraocular P
Tx by decreasing inflow (predominantly), cholinergics to increase outflow 1. Narrow angle = iris blocks outflow (small filtration angle) = EMERGENCY 2. Open angle = trabecular meshwork doesn't line up - fixed by contraction of ciliary m. |
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Where does ↑IOP cause damage?
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Lamina cribrosa - weakest point of sclera where optic nerve enters
= death of ganglion cells (compression AND/OR reduced blood flow) |
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What controls retinal circulation?
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Metabolic!
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What is the difference between retinal and choroid circulation?
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Retinal: paired arteries (arterioles) and veins
Choroidal: short and long posterior ciliary arteries, drained by vortex veins; 100x flow rate relative to retina; mostly autonomic control |
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What supplies photoreceptors with oxygen?
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Primarily choroidal circulation (90%) to 10% retinal
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What is the function of the retinoid pigmented epithelium (RPE)?
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RPE
1. Regeneration of visual pigment after bleaching 2. Phagocytosis of photoreceptors 3. Enact a blood-retinal barrier |
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What is ectropion?
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Drooping of lower eyelid, often in elderly
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What is strabismus? Esotropia? Exotropia? Hypertropia? Hypotropia?
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Strabismus - ocular alignment disorder
When eyes looking forward: Esotropia - outward Exotropia - inward Hypertropia - upward Hypotropia - downward |
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What are two situations that require emergency referral?
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Orbital cellulitis
Painful, new onset diploplia |
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What causes afferent pupillary defect?
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Optic nerve defects
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What are the 5 axes in the DSM classification system?
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I: clinical disorders
II: personality disorders, mental retardation III: General medical conditions IV: Psychosocial, environmental stressors V: Global Assessment of Functioning (GAF) score |
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What is the neurotrophic hypothesis in mood disorders?
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Not just NT defect. More complex:
1. Atrophy, cell damage with stressors in vulnerable individuals 2. ↓ neurogenesis (↓ BDNF) |
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Major depressive episodes = ??
MDE + manic/hypomanic = ?? |
MDD
Bipolar *most people with bipolar disorder often start out with MDD diagnosis |
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What is the ratio of time spent in depression:(hypo)mania in bipolar I and II?
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Bipolar I - 3:1
Bipolar II - 37:1 |
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What is a sedative? Hypnotic? Sedative-hypnotic?
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Sedative - ↓ excitatory response to external stimuli = calming effect
Hypnotic - causes drowsiness and sleep Sedative-hypnotic - calming/drowsiness at low doses, sleep at higher doses |
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Describe the GABAa receptor and where some things bind to it.
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2 α, 2 β, and a γ subunit.
GABA binds at the α-β intersection. BZDs bind at the γ-β junction **γ REQUIRED Barbiturates, ethanol, general anesthetics work here too |
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What is the difference in MOA between BZDs and barbiturates?
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BZDs increase channel opening FREQUENCY
Barbiturates (+ general anesthetics) increase channel opening DURATION (and can open channel at high doses) |
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What is a clinically relevant example of a proconvulsant drug?
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Penicillin!
Uncompetitive inhibitor of GABAa channel (blocks it only when it's open) |
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Which BZDs have no active intermediates?
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LOT
Lorazepam Oxazepam Temazepam Good for elderly (glucuronidation does not decrease as much as CYPs) |
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What is the relationship between ethanol and BZDs?
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Life-threatening if used together (respiratory depression)
BZDs used to treat alcohol withdrawal |
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What is the effect of BZDs on sleep?
Ethanol? Zazoles? Antimuscarinics? |
BZDs:
↓ latency ↑ sleep time ↑ stage 1 and 2 sleep ↓ slow wave and REM sleep Ethanol ↓ REM sleep during first half of sleep period, ↑ slow wave sleep Zazoles normalize sleep Antimuscarinics: ↓ latency ↓ awakenings ↑ slow wave sleep ↓ REM sleep |
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What are some mechanisms of development of anxiety disorders?
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Psychoanalytic theory - incomplete Id repression
Behavioral: • Classical condition (pairing neutral stimulus with physical symptoms) • Operant conditioning (frequency of behavior linked to positive/negative consequences) **Escape paradigm - negative reinforcement - just STOP the behavior = no consequences (e.g. don't go into elevators = no tachycardia) Cognitive: • Inaccurate thinking - overestimation of threat, underestimation of control Biological: • ↑ sympathetic tone |
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What are the risk factors for suicide? (8)
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1. Age - > puberty; adolescents and old people
2. Race - highest in Native American, Alaskan 3. Gender • Males more likely to complete • Females more likely to attempt 4. Psychiatric illness 5. Social risk factors (child abuse, unemployment, financial stress, ...) 6. History of suicide attempts 7. Availability of lethal weapons 8. Biology (concordance, genetics, serotonin) |
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What are the key characteristics defining addiction? (5)
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1. Loss of control
2. Compulsion to use 3. Health consequences 4. Repetitive behaviors in the face of negative consequences 5. Tolerance, withdrawal |
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What % of alcoholism is probably genetic?
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~50%!!
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What are some effects of alcohol on neural circuits?
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↓ glutamate (NMDA)
↑ GABA ↑ dopamine |
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What are the symptoms of delerium tremens?
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2-5d after last drink
• ↑ SNS (tachycardia, tremors, anxiety, seizures) • Psychotic (hallucinations, delusions) • Confusion |
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What are some medications used to decrease alcohol consumption?
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Disulfiram
Naltrexone |
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What is the difference in schizophrenia between men and women?
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Men: earlier onset, more severe
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What two lone symptoms are sufficient to diagnose schizophrenia?
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1. Bizarre delusions - violates laws of chemistry, physics
2. Schneiderian hallucination • Multiple voices discussing the patient in 3rd person • Single voice commenting about person • Thought echo - own thoughts echoed by a voice soon after they are thought |
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What are the subtypes of schizophrenia?
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1. Paranoid - primary delusions and/or auditory hallucinations
2. Disorganized - thoughts and behaviors 3. Residual - (-) symptoms or attenuated (+) symptoms 4. Undifferentiated - variable 5. Catatonic - mutism, negativism |
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What are the phases of schizophrenia?
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0. Premorbid
1. Prodrome - social withdrawal, attenuated (+) symptoms 2. Acute - hallucinations, delusions, change of behavior 3. Residual - (-) symptoms, cognitive impairment and social dysfunction |
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What are the general potential etiologies of schizophrenia?
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1. Stress-diathesis = person with vulnerability succumbs with stress
2. Genetic 3. Viral 4. Environmental |
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What is the main neurotransmitter involved in schizophrenia?
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Dopamine!
↑ in mesolimbic tract = (+) symptoms ↓ in mesocortical tract = (-) symptoms, cognitive symptoms |
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How efficacious are antipsychotics at treating (+) and (-) symptoms of psychosis?
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All treat (+) equally except Clozapine is a little better (but has worst side effects)
2nd generation better for treating (-), although some (-) may be a side effect |
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How long should you treat psychosis before changing medicines?
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4-6 weeks (takes a while to respond to steady state)
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Describe:
1. Mesolimbic 2. Nigrostriatal 3. Mesocortical 4. Tuberoinfundibular |
1. Mesolimbic pathway
• Cell bodies in ventral tegmental area • Projects to limbic system • Emotion, motivation, goal-oriented activity • DA Blockade: blocks (+) symptoms, determines clinical efficacy of antipsychotics 2. Nigrostriatal • Cell bodies in ventral tegmental area • Projects to basal ganglia • Movement • DA Blockade: movement related, "extrapyramidal" side effects 3. Mesocortical • Cell bodies in ventral tegmental area • Project to cerebral cortex (frontal, prefrontal) • (-), cognitive symptoms • DA Blockade: may worsen (-) symptoms 4. Tuberoinfundibular • Hypothalamus • Projects to anterior pituitary • PRL secretion • DA Blockade: removes inhibition of PRL = ↑ PRL = galactorrhea, gynecomastia, amenorrhea, sexual dysfunction |
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What are some other sites of antipsychotics?
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α1 block = orthostatic hypotension, dizziness, sedation
H1 block = sedation, weight gain Muscarinic block = various |
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What is tardive dyskinesia?
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Involuntary, dyskinetic movements of facial, truncal, esophageal, neck, or extremety
Long term, often permanent side effect of long term treatment with antipsychotics (1st gen = higher risk) |
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What are dystonic reactions? How are they treated?
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Painful, acute involuntary muscle spasms
Not life threatening unless they involve airway Tx. with anticholinergics (benztropine, diphenhydramine) |
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What is akathesia?
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Intense sense of restlessness or anxiety - soothed by motion
Risk for violence, suicide Tx: • Switch antipsychotic • Anticholinergics • BZDs • β-blockers (empirically) |
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What is neuroleptic malignant syndrome?
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Develops over 24-72 hours after new antipsychotic or change of dose
Fever Encephalopathy Vitals unstable Elevated enzymes Rigidity of muscles |
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What is different about second generation antipsychotics?
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Additional blockade at 5-HT(2A) receptor
↓ extrapyramidal side effects Apparent efficacy for (-) symptoms |
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What is the risk of mixing SSRIs with MAOIs or triptans?
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Serotonin syndrome:
• Restlessness • Agitation • Euphoria • Myoclonus, seizures, hyperthermia • Delirium, coma, confusion Potentially fatal |
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What are the functions of MAO-A and MAO-B?
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MAO-A = metabolizes monoamines (NE, 5-HT, DA)
MAO-B = converts prototoxins into toxins = important in neurodegenerative like Parkinson's |
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What are some ways to augment the response to antidepressant medications? (4)
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Lithium
Abilify (aripiprazole) - DA partial agonist, 5-HT reuptake inhibitor, α2 inhibitor Thyroid hormone regulation Stimulants - methylphenidate, amphetamine |
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What is a mood stabilizer?
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1. Treats manic episodes
2. Treats depressive episodes without precipitating mania *Unlike antidepressants 3. Prevents depressive, manic episodes |
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Why does decreased Na intake cause lithium toxicity?
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Kidney reabsorbs additional lithium ions (because Li and Na are similar)
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Ego-syntonic vs. ego-dystonic?
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Ego-syntonic - fits with self
Ego-dystonic - doesn't fit with self (e.g. OCD thoughts - "don't know where they come from, want them to go away) |
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Autoplastic vs alloplastic?
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Autoplastic - change self
Alloplastic - change others, environment |
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What is temperament, character, and psyche?
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1.Temperament - innate biases in the modulation of behavioral responses to stimuli - seen in early life
• Harm avoidance • Novelty seeking • Reward dependence • Persistence 2. Character - self-concept and interpersonal relatedness 3. Psyche - consciousness, self-awareness, spirit |
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What IQ defines mental retardation?
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< 70
Spans from mild ("educable") to moderate ("trainable") to severe to profound Severe/profound more likely to be pathological (not multifactorial from random distribution) |
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What are the prenatal causes of mental retardation?
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1. Chromosomal
• Down's Syndrome (trisomy 21) • Trisomy 18 2. Single Gene disorders • Fragile X Syndrome (FMR1 trinucleotide repeat resulting in ↓ transcription) • Noonan syndrome (↑ risk of MR) - AD disorder • Incontinentia Pigmenti (XLD, lethal in males) - rash, seizures, MR in girls 3. Malformational - Multiple congenital anomalies • Brachman-DeLange Syndrome - Isolated CNS malformations • NTDs - uncommon for MR with spina bifida with surgery now • Hydrocephalus • Microcephaly |
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What are the perinatal causes of mental retardation?
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1. Perinatal asphyxia
2. Infectious diseases |
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What are the postnatal causes of mental retardation?
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Deterioration (sudden drop) vs Degeneration (gradual)
Deterioration: • Trauma Degeneration: • Metabolic (e.g. I-cell disease) |
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What are the types of ADHD?
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Inattentive
Hyperactive/impulsive Combined NOS |
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What are the two basic stimulants used to treat ADHD? What is the response rate?
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Methylphenidate
Amphetamine Up to 96% |
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What are second-line drugs for ADHD?
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Atomoxetine
α adrenergic agonists (gaunfacine, clonidine) |
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What is the difference between ASD and PTSD?
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PTSD cannot be diagnosed until symptoms last for 1 mo.
ASD often progresses to PTSD |
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What defines a somatoform disorder?
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Patient with psychiatric illness manifesting as physical symptoms with no underlying physical problem
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What are the components of the mental status exam?
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Appearance
Behavior Speech Mood Affect Thought process Thought content Judgment Insight Cognition |
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What are the 3 main areas of the brain involved with attention?
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1. Mesencephalic reticular formation (MRF)
2. Thalamus 3. Frontal, temporoparietal, limbic regions |
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What is the function of the MRF?
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Excitatory to cortex, intralaminar thalamic nuclei
Inhibits reticular nucleus of thalamus = wakefulness, sensory transmission |
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Which hemisphere is more dominant for attentional control?
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Right
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What is the most common lesion resulting in confusional state?
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Bilateral
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What are the important chemicals involved in confusional states?
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1. ACh (↓) - involved in attention
2. DA (↑) 3. 5-HT (↑ or ↓) 4. GABA (↑ or ↓) 5. Glutamate (↑) 6. Pro-inflammatory cytokines (↑) |
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What are the types of delirium?
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1. Hypoactive - quite, low motor activity, lethargic
• Often in elderly • Hepatic insufficiency 2. Hyperactive - agitated, restless, distractable • Drug/alcohol withdrawal • Anticholinergic toxicity 3. Mixed |
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How is confusion diagnosed?
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1. Acute onset and fluctuating course
+ 2. Inattention AND 3. Disorganized thinking OR 4. Changes in consciousness |
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What are the DSM-IV criteria for autism?
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Severe, qualitative impairment in:
1. Social relatedness 2. Communication 3. Behaviors, interests, and activities 4. Before age 3 |
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Describe:
1. Aspergers 2. Rett's 3. Childhood disintegrative disorder (CDD) 4. Pervasive developmental disorder NOS |
Compared to autism:
1. Aspergers - normal IQ, relatively normal language 2. Rett's - genetic disorder, head growth deceleration, loss of coordination 3. CDD - severe developmental regression after at least 2 years of normal development 4. PDDNOS - subthreshold symptoms |
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What are some brain abnormalities found in autism?
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Larger brains (white matter larger disproportionately, too)
Lower interconnectivity of cortical areas Cerebral asymmetries |
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What is dementia?
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Acquired, progressive deterioration in cognitive function that <b>impairs activities of daily living</b>
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What causes dementia?
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Disruption of neuronal circuits
• Neuronal loss • Synapse dysfunction • Projection systems dysfunction |
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What subset domains are affected by Alzheimers, Frontotemporal dementia, and Lewy body dementia?
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Alzheimers - memory
Frontotemporal - behavior Lew Body - attention, behavior |
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What are the proteins involved in frontotemporal dementia?
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Tau
TDP (tar DNA binding protein) FUS (ubiquitin +) UPS (ubiquitin +) |
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DIG FAST
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Distractability
Irresponsibility Gradiosity Flight of ideas Agitation Sleep ↓ Talkativeness |
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SIG E CAPS
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Sleep changes (↑ or ↓)
Interest ↓ Guilt Energy ↓ Concentration ↓ Appetite/weight (↑ or ↓) Psychomotor (↑ or ↓) Suicidal ideation |
