Biological Bases Flashcards
Central nervous system
brain, spinal cord
Peripheral nervous system
nerves going to and from spinal cord
Somatic nervous system
sends and receives sensory messages that control voluntary motor movement of the skeletal (striated) muscles; part of PNS
Autonomic nervous system
controls automatic or involuntary bodily functions of the smooth muscles and glands, including digestion, heart rate, and breathing; maintains homeostasis; part of PNS; includes sympathetic and parasympathetic nervous systems
Sympathetic nervous system
mobilizing, fight or flight; hormones released in bloodstream to increase respiration, heart rate, and blood pressure and decreases in the processes of digestion and elimination; part of ANS
Parasympathetic nervous system
energy conserving, relaxed; basic body maintenance, slowing heart rate, blood pressure and respiration, and increasing digestion and elimination; part of ANS
Afferent neurons
sensory neurons that carry information to CNS
Efferent neurons
motor neurons carry information from CNS to muscles and glands
Spinal cord regions (top to bottom)
cervical, thoracic, lumbar, sacral
Quadriplegia
paralysis of all four limbs; spinal cord severed C1-C5
Paraplegia
Paralysis of legs; spinal cord severed C6 downward
Severing at C6-C7 = paraplegia and partial paralysis of arms
Paresis
muscle weakness, may result from incomplete severing of spinal cord
Reflexes with spinal cord damage
reflexes still intact
Cerebrum
made of cerebral cortex and subcortical areas
Cerebral cortex
part of cerebrum; outside surface of brain; not fully developed at birth; divided into hemispheres and lobes
Left hemisphere
often dominant (and therefore control language for most people); thinking that is rational, analytical, logical, abstract
Right hemisphere
perceptual, visuospatial , artistic, musical, and intuitive activities; emotion
Frontal lobes
personality, emotionality, inhibition, planning and initiative, abstract thinking, judgment, and higher mental functions (e.g., cognitive flexibility)
Back contains motor control area
Broca’s area in left frontal lobe - controls muscles that produce speech
Broca’s area
In left frontal lobe, controls muscles that produce speech
Parietal lobes
just behind frontal lobes; contain the primary sensory areas that process somatosensory information (light touch, pain , heat, and proprioception)
Gerstmann’s syndrome
involves lesions of the dominant parietal lobe and results in agraphia, acalculia, right-left disorientation, and finger agnosia
Occipital lobes
back of brain, primary visual cortex
Temporal lobes
outsides above temples; primary auditory cortex; emotional behavior and memory; Wernicke’ s area is responsible for thinking about and interpreting language
Subcortical brain areas
Center of the brain and surrounded by cerebral cortex; include the corpus callosum, the thalamus, the hypothalamus, the pituitary, and the limbic system
Corpus callosum
bridge between cerebral hemispheres allowing communication; part of subcortical areas
Split-brain patients
corpus callosum severed to reduce seizures
Thalamus
below corpus callosum; major sensory relay center (except smell), integrates and pr
Hypothalamus
below thalamus; homeostasis through regulating endocrine system; temperature regulation , hunger, thirst, sex, aggression, and the sleep-wake cycle; sex hormone secretion
“ Five F’ s,” namely fever, feeding, fornicating, fighting, and falling asleep
Includes Suprachiasmatic nucleus (SCN)
Suprachiasmatic nucleus (SCN)
controls the body’s circadian rhythm
Pituitary
controlled by hypothalamus; referred to as master endocrine gland; releases hormones to activate adrenal glands; involved in normal and abnormal growth; influences the other endocrine glands including the thyroid, parathyroid, ovaries and testes, pancreas, adrenal cortex, and adrenal medulla
Limbic system
group of interconnected structures involved with emotional behavior, particularly aggression; these structures include the hypothalamus, the hippocampus, the amygdala, the septum, parts of the thalamus, and parts of the frontal and temporal lobes
Stimulating amygdala
results in aggression
Stimulating septum
moderating effect on aggression
Kluver-Bucy syndrome
removal of amygdala; placidity, apathy, hyperphagia, hypersexuality, and agnosias
Septal rage
damaged to septum
Hippocampus
consolidation of memory
Cerebellum
base of brain behind brain stem; maintaining smooth movement and coordinating motor activity; automatic posture adjustments to maintain balance
Brain stem
below the subcortical regions and in front of the cerebellum; includes pons, medulla, and reticular activating system (RAS )
Pons
upper portion of brain stem; with medulla, involved in facial expressions, sleep (including initiation of REM sleep), respiration , movement, and cardiovascular activity
Medulla
bottom of brain stem just above spinal cord; with pons, involved in facial expressions, sleep (including initiation of REM sleep), respiration , movement, and cardiovascular activity
Reticular activating system (RAS)
diffuse set of cells in the medulla, pons, hypothalamus, and thalamus that serve as filter for incoming sensory information; stimulation activates cortex into alert wakefulness
Dendrites
receive information from other neurons; neurons may have hundreds or thoughts
Cell body
soma; integrates information from dendrites
Soma
Cell body
Axon
transmits information from neuron
Boutons
terminal buttons of axon
Absolute refractory period
neuron cannot fire
Relative refractory period
follows absolute refractory period; only very intense stimulation causes firing
Classical neurotransmitters
Acetylcholine (ACh), Catecholamines, Serotonin (5-HT), Amino Acids
Acetylcholine (ACh)
Most common neurotransmitter; involved in voluntary movement and memory and cognition
Prevalent in hippocampus → deficiency in Alzheimer’s
Catecholamines
main ones are dopamine and norepinephrine; synthesized from dietary tyrosine and phenylalanine
Serotonin (5-HT)
mood disorders, aggression, sexual activity, sleep onset, pain perception, and possibly schizophrenia; dietary modification of tryptophan; dysregulation associated with suicidailty and impulsivity
Amino Acids
GABA, Glycine, Glutamate
Agonist
any substance that enhances the effect of the neurotransmitter
Antagonist
any substance that inhibits the neurotransmitter effect
Dopamine hypothesis of schizophrenia
schizophrenia caused by excess of dopamine; until recently all antipsychotics were dopamine antagonists, blocked postsynaptic receptors; questioned because new antipsychotics don’t work this way
Substantia nigra
Produces dopamine, part of basal ganglia
Parkinson’s Disease involves degeneration of this region; L-Dopa (precursor of dopamine) used to treat
Basal ganglia
involved in regulating voluntary movement
Norepinephrine (noradrenalin)
catecholamine/classical neurotransmitter; involved in mood, pain perception, sleep
Catecholamine hypothesis of affective disorders
depression associated with relative deficiency of catecholamines (especially norepinephrine), mania associated with catecholamine excess
Permissive hypothesis of serotonin functioning
deficiency in serotonin permits the expression of affective disorders, but is not sufficient in and of itself; both depression and mania characterized by low serotonin
GABA (Gamma-Aminobutyric Acid) & Glycine
major inhibitory neurotransmitters in the CNS, and they have a calming effect
Insufficient levels associated with anxiety
Benzodiazepines
GABA agonists, increasing levels
Glutamate
major mediator of fast excitatory synaptic transmission
Abnormal glutamate transmission suspected in schizophrenia
Peptide neurotransmitters
Over 25
Regulation of pain and stress
Includes endogenous opioids
Hypopituitarism
syndrome from undersecretion of pituitary hormones; in children can cause dwarfism, pubertal delay; in adults, can cause gonadal failure and other disorders (e.g., hypothyroidism, diabetes, adrenocortical insufficiency)
Hyperpituitarism
startling skeletal overgrowth including acromegaly, which occurs after puberty, and gigantism, which occurs before puberty
Thyroid gland
controls metabolism through secretion of the hormone thyroxin
Hyperthyroidism
weight loss despite increased appetite, heat sensitivity, sweating, diarrhea, tremor and palpitations, fatigue, agitated depression, insomnia, impaired memory and judgment, and can even involve hallucinations and delusions
Hypothyroidism
unexplained weight gain, sluggishness, fatigue, impaired memory and intellectual functioning, and sensitivity to cold; As the disorder progresses myxedematous symptoms appear (dry skin, puffiness, sparse hair, decreased cardiac output); most severe form can involve personality changes, paranoid delusions, delirium, mania, and hallucinations
Grave’s disease
most common form of hyperthyroidism; an immune system disorder that results in the overproduction of thyroid hormones
Myxedema madness
most severe form of hypothyroidism; can involve personality changes, paranoid delusions, delirium, mania, and hallucinations
Parathyroid gland
secretion of calcitonin, which plays a role in calcium retention
Hyperparathyroidism
hypercalcemia with resultant delirium, depression, apathy and personality changes, psychosis, and stupor or coma
Hypoparathyroidism
neuromuscular symptoms, ranging from parasthesias (tingling) to tetany (including cramps and convulsions); personality changes and delirium
Pancreas
secretes insulin
Diabetes Mellitus Type I
called Juvenile Onset or Insulin Dependent Diabetes Mellitus (IDDM); more serious; associated with difficulty maintaining good control in adolescence
Diabetes Mellitus Type II
Adult Onset, Non-Insulin Dependent Diabetes Mellitus (NIDDM)
Diabetes Insipidus
relatively rare, can be caused by lithium toxicity; imbalance in fluids, pee a lot, feel thirsty
Adrenal cortex
corticosteroids that are involved in the use of energy resources, the inhibition of antibody formation, and inflammation
Addison’s disease
Undersecretion of corticosteroids, or adrenal insufficiency; symptoms of apathy, weakness, irritability, depression, and gastrointestinal disturbance
Cushing’s disease
Oversecretion of corticosteroids; symptoms of agitated depression, irritability and emotional lability, difficulties with memory and concentration, and even suicide; adiposity (swelling and fattening) of the face, neck, and trunk
Hypoglycemia
abnormally low blood sugar; nervousness, irritability, trembling, cold sweats, fatigue, rapid heart rate, hunger, headache, and confusion
Hyperglycemia
high blood sugar; frequent in diabetes; increased thirst and urination, dehydration, fatigue and weakness, abdominal pain, nausea, and loss of appetite
Cognitive disorders
includes the effects of stroke, trauma, and brain tumors, as well as dementia, delirium, and amnestic disorders
Aphasia
language disorder, and results from damage (also called lesions) in the left hemisphere
Broca’s aphasia
lesions to the left frontal lobe, specifically to the motor strip area, which controls the muscles that produce speech; severe problems with articulation; short phrases punctuated by lengthy pauses; comprehension mostly intact (challenges with passive grammatical constructions); expressive or motor aphasia
Dysarthria
severe problems with articulation
Wernicke’s aphasia
lesions in left temporal lobe; no language comprehension; speak fluently but complete nonsense; unaware of problem, expect others to understand; receptive or sensory aphasia
Conduction aphasia
lesions in the connections between the expressive and receptive speech areas; intact language comprehension, speak fluently, but are unable to repeat verbal phrases; speak fluently but make no sense; able to execute verbal commands because still understand language
Global aphasia
damage to much of cortex, most language functions impaired (fluency, comprehension, repetition, naming, reading, and writing)
One-sided neglect
damage occurs to one side of brain; neglect occurs secondary to sensory losses (e.g., forgetting to dress one side of body, eating food from one side of plate)
Apraxia
inability to carry out purposeful motor movements (e.g., waving), despite the absence of motor or sensory deficits; can move limbs normally but innervates the wrong muscles, puts the limbs in an incorrect position or omits some element of action when asked to carry out a specific motor command; believed to be associated with left brain lesion
Agraphia
impairment in the ability to write, acquired after the person has learned to write; deficits in a variety of aspects of writing including spelling, word selection, grammar or spatial arrangement; left hemisphere damage in variety of regions (frontal lobe, temporal or parietal regions, and basal ganglia)
Alexia
acquired partial or complete inability to read; most common cause is stroke to dominant hemisphere; pure alexia (without agraphia) associated with lesions that disconnect the visual association cortex from the temporoparietal cortices
Prosopagnosia
inability to recognize a familiar face; occurs both retrograde (the inability to recognize the faces of previously known individuals) and anterograde (the inability to learn new faces); thought due to injury to areas of visual cortex
Anosognosia
lack of awareness of nature of one’s illness
Hydrocephalus
pathological accumulation of cerebrospinal fluid (CSF) in the brain’ s ventricles, causing increased intracranial pressure; over-production or malabsorption of CSF, malabsorption more common; symptoms include dementia, urinary incontinence, or an unsteady gait; caused by head injuries, tumors, meningitis or encephalitis; treated with surgical procedure
Dementia
evidence of significant cognitive decline in one or more domains (learning and memory, language, executive functioning, complex attention, perceptual-motor, social cognition); interfere with everyday activities
Alzheimer’s disease
most common form of dementia; more prevalent in women; definitive diagnosis only from biopsy or autopsy; progressive course; cortical dementia, with memory, language, and praxis most affected; evidence for genetic component; Senile plaques (protein globes) and neurofibrillary tangles (pairs of tangled neuronal filaments) are found throughout the cortex and other brain structures, especially the hippocampus (associated with memory) and amygdala; decrease in acetylcholine (ACh), which is involved in learning and memory
Vascular dementia
more common in men; results from numerous small CVAs (cerebrovascular accidents) or strokes; abrupt onset, rapid course, step-wise; death often withn years of onset; lifestyle changes effective in arresting progress; aspirin, anticoagulants, and antihypertensives to reduce future strokes
Parkinson’s disease
movement disorder marked by tremor, rigidity, bradykinesia, and shuffling gait; slightly more men; neuropsychiatric symptoms, such as psychosis, dementia, and depression
Parkinson’s dementia
dementia associated with Parkinson’s; sub-cortical dementia, affecting speed of processing and executive functions (planning, organizing, sequencing); associated with degeneration of neurons in the substantia nigra, a section of the basal ganglia; decrease in dopamine; L-Dopa treats movement components but does not alter progression; depression in 50-90%; antidepressants may improve emotional and cognitive functioning
Bradykinesia
slowed initiation of movement
Huntington’s disease (chorea)
results from an autosomaldominant gene; involves basal ganglia; acetylcholine and GABA implicated; not apparent until age 35-45; personality change often first sign; progressively deteriorating dementia; choreiform movements, athetosis, and facial grimaces begin months to years after onset of disease
Choreiform movements
frequent, discrete, brisk jerking movements of the pelvis, trunk, and limbs
Athetosis
slow writhing movements
Pick’s disease
rare dementia; clinically indistinguishable from Alzheimer’s; twice as many women as men; onset peaking 50s and 60s; affects predominantly the frontal and temporal lobes; decreases in initiative, episodes of tactless and inappropriate behavior, facetiousness and euphoria, explosive temper, disinhibition and poor impulse control, and impaired insight; Problems with memory and language are also common, however, apraxias and agnosias are less common than in Alzheimer’s; neurons swell and have “ Pick bodies” (i.e., irregularly shaped inclusions); treatment has not been much studied
AIDS dementia complex
dementia caused by HIV; approximately 10-15% of people with AIDS; cognitive (memory but not long term memory, attention/concentration, language), motor (weakness, lack of coordination, unsteady gait, and jerky eye movements), and behavioral changes (apathy, withdrawal, lack of motivation, personality changes, inappropriate affect, mood swings, and even hallucinations)
closed head injuries
head injuries in which the skull is not pierced or cracked; most common are concussions and contusions; often result in loss of consciousness; impairments discrete and/or general
concussion
blow to the head, hard enough to cause temporary neural dysfunction, but not hard enough to cause a cerebral contusion (bruising); most common head injury; may cause short-term loss of consciousness, anterograde amnesia, retrograde amnesia (typically events just before injury or event itself)
postconcussion syndrome
somatic and psychological symptoms including headache, dizziness, fatigue, diminished concentration, memory deficit, irritability, anxiety, insomnia, hypochondriacal concern, hypersensitivity to noise, and photophobia; most common irritability, headaches, fatigue, dizziness
contussions
severe blow to the head where there are coup-countrecoup injuries; may lose consciousness for minutes to an hour, and if conscious may be drowsy, confused, agitated , and even violent; returning to alert state, may experience temporary aphasia, slight hemiparesis, or unilateral numbness
coup-contrecoup injuries
bruising beneath the point of impact as well as on the opposite side of the brain
discrete impairment (head injury)
results from injury at the site of the coup or countrecoup, most frequently the frontal and temporal lobes; often frontal lobe syndromes with significant impacts on personality and social adjustment
diffuse impairment
(head injury)
loss of complex cognitive functions (e.g., reductions in mental speed, ability to concentrate, and overall cognitive efficiency)
open head injuries
involve penetration of skull; many do not lose consciousness; neurological signs often highly specific
recovery from head trauma
bulk happens in first 6-9 months, can continue for 2-3 years; recovery of memory typically slower than general intelligence
pseudodementia
cognitive impairment due to depression (slower processing speed, difficulties in concentration and attention, psychomotor retardation, social withdrawal, and easily giving up on difficult items when tested); acute onset, association with personal loss or emotional distress, and rapid progression; more likely to complain of memory loss; treatment for depression often improves
delirium
acute confusional state; results from disturbances in consciousness; reduced ability to focus, sustain, or shift attention; change in cognition (memory deficit, disorientation) or development of a perceptual disturbance; acute onset and fluctuating course; most likely to be reversible; often additional neurological signs and disturbed sleep; common causes are infections, metabolic and endocrine disorders, postoperative states, substance intoxication (medications or illicit drugs), and substance withdrawal
neurotransmitter involved in delirium
acetylcholine thought to be involved
drug of choice for delirium
ativan, sometimes antipsychotics
amnestic disorders
disturbance in memory related to effects of general medical condition or persisting effects of substance; most common are head trauma and alcohol abuse; problems with memory only
Korsakoff’s syndrome
thought to be caused by the chronic thiamin (Vitamin B1) deficiency associated with alcoholism; anterograde amnesia, especially learning new paired associates lists; also suffer retrograde amnesia; confabulate; lack of insight, limited spontaneous conversation; normal IQ, alert, attentive, generally motivated
confabulate
make up plausible stories about past events that did not occur
effects of ECT
can result in memory loss; bilateral frequently induces memory changes; cumulative effects; most effects reversible; more complaints of retrograde amnesia; unilateral ECT on the left side preferentially disturbs verbal memory, while unilateral right sided ECT preferentially disturbs nonverbal memory
Melzak & Walls
Gate control theory of pain (1965)
gate-control theory
sensations of pain not directly related to activation of pain receptors but mediated by neural gates in the spinal cord that allow signals to continue to brain; pressure stimulation tends to close gate; psychological factors such as attitudes and moods can also impact
best management of chronic pain drugs
time-contingent (fixed interval) schedule (rather than based on pain)
beta waves
predominate when person is awake and attentive
alpha waves
predominate when a person closes eyes or relaxes; 8 to 12 Hz
theta waves
predominate during first stage when falling asleep; 4 to 8 Hz
delta waves
slow waves of 1 to 2 Hz; predominate during third and fourth stage
Spindles
rhythmical responses of 12 to 16 Hz
Stage 1 (sleep)
non-REM; little alpha, predominance of theta waves; brief transitional stage between awake and asleep
Stage 2 (sleep)
non-REM; characterized by spindles; greatest amount of time while asleep
Stage 3 & 4 (sleep)
non-REM; characterized by delta waves; hard to awaken; more prominent in first half of night
REM sleep
patterns of stage 1 with rapid eye movements (little alpha, predominance of theta); newborns spend a lot of time here; more prominent in second half of night
Generalized seizures
occur when electrical abnormalities exist throughout the brain; include tonic clonic seizures and petit mal seizures
Tonic clonic seizures
tonic stage (continous tensions or contraction) followed by clonic stage (rapid, involuntary, alternating muscular contractions, and relaxation); occur during grand-mal seizures
Grand mal seizures
dramatic and involve convulsions throughout the body; generalized seizure; loss of consciousness common; after, typically experience headache, confusion, fatigue, and amnesia for the seizure
Petit mal seizures
also called absence seizures; most common in children before age 5; last 1-30 seconds; brief change in level of consciousness, followed by blinking or rolling of the eyes, a blank stare, and slight mouth movements, such as twitching
Simple partial seizure
electrical abnormalities in focal area of brain only; usually remains conscious and can describe it in detail
Jacksonian seizures
partial seizure; initially localized motor seizure, with a spread of abnormal activity to adjacent brain areas
Complex partial seizure
typically preceded by an aura, and usually include purposeless behavior (e.g., aimless wandering), lip smacking, and unintelligible speech; consciousness impaired; confusion may last for several more minutes; ultimately makes full recovery
Tests of brain function
PET scan; MRI; CAT scan
PET scan
positron emission tomography; demonstrating brain activity or functioning; shows functional capacity of particular brain region
MRI
magnetic resonance imaging; visualization of brain structures; utilizes radio waves rather than x-rays
CAT scan
computerized axial tomography; viewing brain structure; results in x-ray like pictures that are more clear and accurate
Synesthesia
one type of sensory stimulation elicits another sense; two or more senses connected (e.g., smelling colors)
Hans Seyle
developed General Adaptation Syndrome
General Adaptation Syndrome
model of response to severe stress with three stages: alarm, resistance, exhaustion
Alarm (General Adaptation Syndrome)
mobilizes resources; sympathetic nervous system activated; high alert, but lowered resistance to illness; symptoms include headache, fatigue, diarrhea
Resistance (General Adaptation Syndrome)
alarm subsides, body adapts to stressor, level of resistance to illness above normal
Exhaustion (General Adaptation Syndrome)
response to chronic, unremitting stress; resources exhausted, stress hormones depleted; loss of health and possibly death
Rosenstock
health belief model
