Chapter 1: Biology and Behavior Flashcards Preview

MCAT Psychology > Chapter 1: Biology and Behavior > Flashcards

Flashcards in Chapter 1: Biology and Behavior Deck (87):

Organization of human nervous system

- Brain and spinal cord

- Somatic
- Autonomic > Sympathetic and parasympathetic


Sensory neurons

Afferent neurons; transmit sensory info from receptors to spinal cord and brain


Motor neurons

Efferent neurons; transmit motor information from the brain and spinal cord to muscles and glands



Located between other neurons, most commonly found in brain and spinal cord; often linked to reflexive behavior (e.g. reflex arcs)


Reflex arc

In response to sensory info, interneurons send efferent motor signal to muscles before sensory info reaches brain


Somatic nervous system

Sensory and motor neurons distributed throughout skin, joints, and muscles


Autonomic nervous system

- Regulates heartbeat, respiration, digestion, temperature, and glandular secretions (involuntary/automatic muscles associated with many internal organs and glands)
- Subdivided into sympathetic and parasympathetic nervous systems


Parasympathetic nervous system

- "Rest and digest"
- Conserves energy, associated with resting and sleeping states; slows heart rate, stimulates digestion, constricts bronchi, contracts bladder
- Response mediated by acetylcholine


Sympathetic nervous system

- "Fight or flight"
- Activated by stress
- Increases heart rate, increases blood flow to required muscles, increases blood glucose concentration, relaxes bronchi, decreases digestion, dilates eyes, releases epinephrine into blood stream


Meninges (function and layers)

- Cover the brain with thick sheath of connective tissue
- Protect the brain, keep it anchored in skull, resorb cerebrospinal fluid
- 3 layers (inside to outside): pia mater, arachnoid mater, dura mater


Cerebrospinal fluid

- Aqueous solution in which the brain and spinal cord rest
- Produced by specialized cells that line the ventricles (internal cavities of the brain)


Hindbrain (components and functions)

- Medulla, pons, cerebellum, reticular formation
- Balance, motor coordination, breathing, digestion, general arousal process (sleeping, waking)


Cerebellum (location, function, and symptoms of damage)

- Hindbrain
- Balance and refined motor movements, speech, movement of eyes
- Damage: clumsiness, slurred speech, loss of balance (affected by alcohol)


Medulla (location and function)

- Hindbrain
- Vital functioning (breathing, heart rate, blood pressure, digestion)


Reticular formation (location and function)

- Neurons somas scattered throughout brainstem
- Arousal and alertness


Pons (location and function)

- Hindbrain
- Sensory and motor pathways between cortex and medulla



- Receives sensory and motor information from rest of body
- Involuntary reflexes in response to visual (superior colliculus) or auditory stimuli (inferior colliculus)



- Complex perceptual, cognitive, and behavioral processes
- Emotion and memory
- Components: cerebral cortex, basal ganglia, limbic system, thalamus, hypothalamus, posterior pituitary gland, pineal gland


Cortical maps

Cortex is stimulated with small electrode > individual neurons fire > behavioral or perceptual processes are activated; used by neurosurgeons


Electroencephalogram (EEG) (purpose and method)

- Measures electrical activity generated by larger groups of neurons
- Noninvasive; recorded by placing electrodes on scalp
- Used for research on sleep, seizures, brain lesions


Regional cerebral blood flow (rCBF) (purpose and method)

- Detects broad patterns of neural activity based on increased blood flow to different parts of brain
- Assumption: active regions have increased blood flow
- Noninvasive; patient inhales harmless radioactive gas, radioactivity is then correlated with blood flow


Computerized tomography (CT)

Multiple X-rays taken at different angles and processed by computer to produce cross-sectional slice images of tissue


Positron emission tomography (PET)

- Radioactive sugar is injected and absorbed into body, dispersion and uptake throughout target tissue is imaged
- Can't give detailed structure, but can if combine with CAT and MRI


Magnetic resonance imaging (MRI)

- Uses magnetic field to interact with hydrogen and map out hydrogen dense regions of the body
- Dependent on reaction of hydrogen to magnetic field (same concept as NMR)


Functional magnetic resonance imaging (fMRI)

- Same technique as MRI, but measures changes associated with blood flow. Useful for monitoring neural activity


Radiofrequency lesions

- Used to destroy tissue on surface of brain and deep inside brain
- Wire inserted into brain to determine area, high frequency current heats up wire and destroys cells and axons


Neurochemical lesions

- Excitotoxic lesions: cause influx of calcium that excites the neuron to death
- Kainic acid: destroys cell bodies but not axons
- Oxidopamine: selectively destroys dopamine and norepinephrine neurons; models Parkinson's disease


Cortical cooling (cryogenic blockade)

- Lesion method: cool neurons until they stop firing
- Cryoloop: surgically implanted between skull and brain; reversible unlike other techniques


Techniques for imaging brain structure, function, and both

Structure: CAT scan (CT), MRI
Function: EEG, MEG
Both: fMRI, PET (esp. when combined with CT/MRI)



- Forebrain
- Relay station for all sensory information except smell
- Receives sensory info and then transmits to appropriate area of cerebral cortex


Hypothalamus (general overview)

- Forebrain
- Controls 4 Fs: feeding, fighting, flighting, and mating
- Regulates autonomic nervous system to serve homeostatic functions: metabolism, temperature, water balance
- Integrates with endocrine system through hypophyseal portal system connecting it to anterior pituitary
- Further divided into lateral, ventromedial, and anterior hypothalamus


Lateral hypothalamus

- Hunger center; receptors detect when body needs food or water
- When this part is destroyed one [Lacks Hunger]


Ventromedial hypothalamus

- Satiety center; provides signals to stop eating
- Lesions to this area usually result in obesity
- [Very Much Hungry] when destroyed


Anterior hypothalamus

- Controls sexual behavior, regulates sleep and body temperature
- Damage inhibits sexual behavior


Posterior pituitary gland (location and function)

- Comprised of axonal projections from hypothalamus
- Site of release of antidiuretic hormone (i.e. vasopressin) and oxytocin


Pineal gland

- Secretes hormone melatonin, which regulates circadian rhythms by receiving direct signals from retina


Basal ganglia (function and effects of damage)

- Coordinate muscle movement as they receive info from cortex and relay (via extrapyramidal motor system) to the brain and spinal cord
- Essentially make movements smooth and posture steady
- Damage associated with Parkinson's


Limbic system (location, overall function, and components)

- Interconnected structures looped around central portion of brain
- Primarily associated with emotion and memory
- Primary components: septal nuclei, amygdala, hippocampus
- [Hippo wearing a HAT]


Septal nuclei (location and function)

- Limbic system
- One of the primary pleasure centers of the brain. Mild stimulation is intensely pleasurable
- Association between these nuclei and addiction


Amygdala (location, function, and effects of damage)

- Limbic system
- Aggression center; stimulation produces anger/violence + fear/anxiety. Destruction causes mellowing effect
- Kluver-Bucy syndrome: bilateral destruction of amygdala, can result in hyperorality (put things in mouth a lot), hypersexuality, and disinhibited behavior


Kluver-Bucy syndrome

Bilateral destruction of amygdala, can result in hyperorality (put things in mouth a lot), hypersexuality, and disinhibited behavior


Hippocampus (location, function, effects of damage)

- Limbic system
- Consolidates info from short term memory to long term memory; damage prevents formation of new memories (anterograde amnesia)
- Can redistribute remote memories to cerebral cortex
- Communicates with limbic system through projection called fornix


Anterograde amnesia

- Unable to form new long-term memories, but memories from before brain injury remain intact
- Caused by damage to hippocampus


Retrograde amnesia

- Memory loss of events that transpired before brain injury


Cerebral cortex

- Outer surface of brain
- Divided into two halves called cerebral hemispheres; positive emotions evoke more activity in left side, negative emotions evoke more activity in right side
- Divided into four lobes [F-POT]: frontal, parietal, occipital, and temporal


Frontal lobe (location, divisions, overall functions)

- Part of cerebral cortex
- Two basic regions: prefrontal cortex, motor cortex
- Executive function, impulse control, long-term planning, motor function, speech production


Prefrontal cortex

- Part of frontal lobe
- Supervises processes associated with perception, memory, emotion, impulse control, long-term planning, decision-making, problem solving
- Damage to Phineas Gage caused him to be rude and inappropriate


Association area

Area that integrates input from diverse brain regions


Projection area

Perform rudimentary or simple perceptual and motor tasks (vs. association area)


Motor cortex

- Part of frontal lobe
- Initiates voluntary motor movements by sending neural impulses down spinal cord toward the muscles
- Considered projection area
- Neurons arranged systematically according to the part of the body they control
- Areas requiring finer motor control take up more space in motor cortex


Broca's area AND Wernicke's area

Broca's area:
- Part of frontal lobe, found only on dominant hemisphere (usually the left)
- Speech production ["Brocering" a deal]

Wernicke's area:
- Part of temporal lobe
- Language reception and comprehension


Parietal lobe (location and function)

- Part of cerebral cortex; located just behind frontal lobe
- Somatosensory cortex projection area processes all incoming signals for tough, pressure, temperature, and pain
- Closely related to motor cortex (leads to name sensorimotor cortex)
- Central region associated with spatial processing and manipulation (for objects, maps, etc.)


Occipital lobe (location and function)

- Part of cerebral cortex; located at rear of brain
- Contains visual cortex
- May also be implicated in learning and motor control


Temporal lobe (location, function, key components)

- Part of cerebral cortex, located at sides of brain
- Auditory cortex: sound processing, including speech, music, etc.
- Wernicke's area: associated with language reception and comprehension
- Memory processing, emotion, and language
- Electrical stimulation can evoke memories for past events (hippocampus located deep inside parietal lobe)


Cerebral hemisphere laterality

- Motor neurons work contralaterally, hearing works ipsilaterally
- Dominant hemisphere (usually left): language (Broca, Wernicke), logic, and math skills
- Non-dominant hemisphere (usually right): intuition, creativity, music cognition, and spatial processing, mood recognition


Visual system laterality

Dominant (L): letters, words
Non-dominant: faces


Auditory system laterality

Dominant (L): language
Non-dominant: music


Language laterality

Dominant (L): speech, reading, writing, arithmetic
Non-dominant: emotions


Movement laterality

Dominant (L): complex voluntary movement


Spatial processing laterality

Non-dominant (R): geometry, sense of direction



- CNS: Released by basilis and septal nuclei in frontal lobe to cerebral cortex; attention and arousal
- PNS: Released to somatic system for voluntary muscle control, autonomic (parasympathetic) nervous system
- Loss of cholinergic neurons connecting with hippocampus is associated with Alzheimer's disease


Epinephrine and norepinephrine

- Primary catecholamine neurotransmitter of sympathetic nervous system; promote fight-or-flight response
- Norepinephrine acts as local neurotransmitter; low levels = depression, high levels = anxiety/mania; secreted by locus cereleus in pons
- Epinephrine secreted from adrenal medulla to act systematically as hormone



- Catecholamine that plays important role in smooth movement and posture, esp. in basal ganglia
- Imbalances cause schizophrenia and Parkinson's (esp. in basal ganglia)



- Secreted by raphe nuclei in midbrain/medulla
- Regulates mood, eating, sleeping, dreaming
- Oversupply = mania; undersupply = depression


GABA (brain) and Glycine (spinal cord)

- Most common inhibitory neurotransmitters
- GABA causes hyperpolarization of postsynaptic membrane
- Glycine also causes hyperpolarization of postsynaptic membrane: by increasing chloride influx



- Secreted by reticular activating system to cerebral cortex for consciousness
- Most common excitatory neurotransmitter


Peptide neurotransmitters

- A.k.a. neuromodulators, neuropeptides
- Endorphins and enkephalins: natural painkillers
- Requires more complicated chain of events in postsynaptic cell than regular neurotransmitters; slow response, longer effects



- Chemical messengers of endocrine system
- Slower response than neurotransmitters because they travel through bloodstream to reach target
- Release controlled by hypothalamus and the hypophyseal portal system of pituitary gland


Pituitary gland (location and function)

- Located at back of brain
- Anterior pituitary: controlled by hypothalamus; releases hormones that regulate activities of endocrine glands


Adrenal glands (location, sub-divisions, and functions)

- Located on top of kidneys
- Adrenal medulla: releases epinephrine and norepinephrine as part of sympathetic nervous system
- Adrenal cortex: produces corticosteroids (like cortisol), sex hormones (testosterone and estrogen)



- Sex glands (testes in males and ovaries in females)
- Produce testosterone and estrogen
- Increase libido
- High testosterone => aggressive behavior


Innate behavior

Genetically programmed as a result of evolution and is seen in all individuals regardless of environment or species

Examples: Reflexes, taxis (bugs fly toward light), kinesis (rats' random scurrying)


Learned behavior

Behaviors based on experience and environment rather than heredity

Examples: Habituation (response to stimulus decreases over time), classical conditioning, operant conditioning, insight learning (solving a problem using past skills), latent learning (learned behavior not expressed until required)


Adaptive value

The extent to which a trait or behavior positively benefits a species by influencing evolutionary fitness of species, thus leading to adaptation through natural selection


Family studies

Assume similar genotype; compare rates of trait among family members to those of unrelated individuals. Limited because families share both genetics and environment


Twin studies

Compare concordance rates (likelihood of sharing same trait) for trait between monozygotic (identical) and dizygotic (fraternal) twins.


Adoption studies

Compares biological and adoptive relatives to adopted child to investigate nature vs. nurture


Reflex (general)

Behavior that occurs in response to given stimulus without higher cognitive input


Primitive reflex

Reflexes that disappear with age


Rooting reflex

Primitive reflex; automatic turning of head in direction of a stimulus that touches the cheek


Moro reflex

Primitive reflex; Infants react to abrupt movement of head by flinging out arms, then slowly retracting arms and crying


Babinski reflex

Primitive reflex; causes toes to spread automatically when sole of foot is stimulated


Grasping reflex

Primitive reflex; occurs when infant closes fingers around object placed in hand. Also present in adults with diseases that cause demyelination.


Developmental milestone trends in gross motor skills, social skills, language skills

Motor skills
- Progress in head to toe order
- Skills at core develop before skills at extremities

Social skills
- Move from being parent-oriented to self-oriented

Language becomes more complex and structured


Stranger anxiety and separation anxiety ages

7 months, 1 year, respectively



Stress hormone produced by adrenal cortex


Neurulation process

- Notochord stimulates overlying ectoderm to fold over, creates neural tube topped with neural crest cells
- Neural tube becomes CNS
- Neural crest spreads and differentiates throughout body