MCAT Behavioral Sciences P2.

Part 2 of the MCAT social sciences

kinesthetic sense

the sense of body position and movement of body parts relative to each other

pinna

aka auricle; the outer ear begins with this; the outwardly visible part of the ear that functions as a kind of funnel for sound, channeling sound waves through the external auditory canal and to the tympanic membrane (colloquially known as the eardrum)

external auditory canal

The ear canal; leads to the tympanic membrane; transmits sound waves from the pinna to the tympanic membrane of the middle ear

tympanic membrane

a membrane forming part of the organ of hearing, which vibrates in response to sound waves. In humans and other higher vertebrates it forms the eardrum, between the outer and middle ear

ossicles

three tiny bones in the middle ear (malleus, incus, stapes)

malleus

hammer; first of the three auditory ossicles of the middle ear

incus

anvil; middle of the three auditory ossicles of the middle ear

stapes

stirrup; last of the three auditory ossicles of the middle ear. The connection between the middle and inner ear, with the baseplate connected to the cochlea and oval window

cochlea

a coiled, bony, fluid-filled tube in the inner ear; sound waves traveling through the cochlear fluid trigger nerve impulses

oval window

membrane at the entrance to the cochlea through which the ossicles transmit vibrations

eustachian tube

connects the middle ear with the nasopharynx and allows passage of air; narrow tube; connects middle ear to the nasal cavity and helps to equalize pressure between the ear and the environment

vestibule

makes up the middle portion of the internal ear that contacts the stapes; contains two compartments, the utricle and saccule (accts for linear acceleration)

semicircular canals

three fluid-filled canals in the inner ear responsible for our sense of balance (accts for rotational acceleration)

bony labyrinth

protects the inner ear

membranous labyrinth

membrane-covered tubes inside the bony labyrinth; contains endolymph (a potassium rich fluid)

perilymph

a thin layer of fluid between the bony labyrinth and the membranous labyrinth; transmits vibrations from the stapes and protects the membranous labyrinth

scalae

3 chambers of the cochlea

central scala

section of cochlae protected by the flexible basilar membrane that contains the organ of Corti

basilar membrane

A structure that runs the length of the cochlea in the inner ear and holds the auditory receptors, called hair cells.

organ of Corti

the actual hearing apparatus of the ear; Center part of the cochlea, containing hair cells bathed in endolymph, canals, and membranes

auditory nerve

bundle of axons from the hair cells in the inner ear; the cranial nerve that carries impulses from the inner ear to the brain, resulting in the perception of sound

vestibulocochlear nerve

other name for auditory nerve

stereocilia

hairlike extensions on the tips of hair cells in the cochlea that initiate the release of neurotransmitters when they are flexed

tonotopically

how the cochlea is arranged, meaning that different hair cells in different parts pick up different kinds of sounds; brain can assess the quality of a sound based upon which hair cells are vibrating

utricle

the larger of two sacs within the membranous labyrinth of the vestibule in the inner ear

saccule

the smaller of two sacs within the membranous labyrinth of the vestibule in the inner ear

otoliths

specialized hair cells within the utricle and saccule; resist motion as the body accelerates and send information to the brain

medial geniculate nucleus

a group of cell bodies within the medial geniculate body of the thalamus; receives fibers from the auditory system and projects fibers to the primary auditory cortex

ampulla

dilated portion of a canal or duct; houses hair cells at the end of the semicircular canals

superior olive

serves to localize sound information; an early brain stem region in the auditory pathway where inputs from both ears converge

inferior colliculus

a midbrain nucleus in the auditory pathway; responsible for the startle reflex (aka moro reflex)

vestibulo-ocular reflex (VOR)

A short-latency reflex that helps stabilize vision by counterrotating the eyes when the vestibular system senses head movement; helps keep the eyes fixed on a single point in space while head rotates

olfactory chemoreceptors

located in the olfactory epithelium in the upper part of the nasal cavity

olfactory pathway

Odor -> olfactory nerves in olfactory epithelium -> olfactory bulb -> olfactory tract

olfactory bulb

the brain center for smell, located below the frontal lobes; the first brain structure to pick up smell information from the nose

olfactory tract

the path along which the olfactory receptors send their electrical messages to the brain after the bulb

Limbic system

• Complex structure located on both sides of the thalamus

  • Includes: the hippocampus, amygdala, and hypothalamus.

• A doughnut-shaped system of neural structures at the border of the brainstem and cerebral hemispheres

  • Receives info from olfactory tract

• Associated with emotions such as fear and aggression and drives such as those for food and sex.

papillae

taste buds

taste center

located in the thalamus; taste information travels from taste buds to the brainstem, and then ascend to this before traveling to higher-order brain regions

flavor

represents confluence of both smell and taste

somatosensation

The body senses, including body position, touch, skin temperature, and pain; includes four modalities: pain, pressure, temperature, and vibration.

free nerve endings

respond to pain and temperature

Miessner's corpuscles

tactile receptors; sense light touch

merkle discs

sense deep pressure and texture

Pacinian corpuscles

sense deep pressure and vibration

Ruffini endings

sense stretch

two-point threshold

the minimum distance between two points being stimulated concurrently on the skin where those two points will be felt distinctly from one another; distance varies with the density of nerves in the skin

physiological zero

the normal temperature of the skin, ranging between 86 and 97 degrees F

Gate Theory of Pain

• Holds that our bodies have the ability to "gate" pain signals, turning them on or off with a special mechanism in the spinal cord.

• Can be preferential of which signals from which modalities of somatosensation it sends to the brain

  • Explains how pain thresholds vary from person to person

parietal lobe

A region of the cerebral (somatosensory) cortex whose functions include processing information about touch.

proprioception

The cumulative sensory input to the central nervous system from all mechanoreceptors that sense body position and limb movement; sense of body position in space

binocular and stereoscopic vision

overlapping fields of vision allowing for depth perception; the benefit of the crossing over of optic nerve fibers at the optic chiasm

Recognition-Primed Decision Model

• Decision making model

• Experience and recognition of similar situations has already played a large role in decision making and actions

  • Explains for experience of using intuition.

Object Permanence

• Knowledge that an object does not cease to exist even when the object cannot be seen

• A milestone in cognitive development.

Narcolepsy

• Sleep disorder

• Lack of voluntary control of onset sleep

  • Involves cataplexy and hypnagogic and hypnopompic hallucinations.

Mental Set

A tendency to repeat solutions that have yielded positive results at some time in the past.

Linguistic Relativity Hypothesis

• A hypothesis suggesting that one's perception of reality is largely determined by the content, form, and structure of language

• Known as the Whorfian hypothesis.

Behavioural (Learning) Theory or Behaviorist Theory

• A theory that attitudes are developed through forms of learning.

  • E.x. direct contact, direct interaction, direct instruction, and conditioning.

Intuition

• Perceptions about a situation that may or may not be supported by available evidence.

• Nonetheless perceived as information that may be used to make a decision.

Intelligent Quotient

• Numerical measurement of intelligence, usually accomplished by some form of standardized testing.

  • E.x. MCAT scores

Hallucinations

• Perceptions that are not real or external stimuli but seem real.

• Drugs such as lysergic acid diethylamide (LSD) or psilocybin-containing mushrooms, are termed hallucinogens

Functional Fixedness

The inability to identify uses for an object beyond its usual purpose.

Errors of Growth

• Misuse of grammar characterized by universal application of a rule, regardless of exceptions

• Seen in children during language development.

Egocentrism

• Self-centered view of the world in which one is not able to understand the experience of another person.

• In Piaget's Theory on Cognitive Development

  • Ages 2-7: preoperational stage

Divided Attention

The ability to attend to multiple stimuli simultaneously and to perform multiple tasks at the same time.

Disconfirmation Principle

• Idea that, if evidence obtained during testing does not confirm a hypothesis, then the hypothesis is discarded or revised.

Critical Period

• A time during development during which exposure to language is essential for eventual development of effective use of language

• Between two years of age and puberty.

Conservation

• Concept seen in quantitative analysis performed by a child.

• Develops when a child is able to identify the difference between quantity by number and actual amount.

  • Even when faced with identical quantities separated into varying pieces.

Consciousness

• Awareness of oneself

• Described in varying levels of awareness that occur with wakefulness, sleep, dreaming, and drug-induced states.

Circular Reaction

• A repetitive action that achieves a desired response

• Seen during Piaget's Theory of Cognitive Development

  • Ages 0-2: Sensorimotor stage

Arcuate Fasciculus

• A bundle of axons that connects Wernicke's Area (language comprehension) with Broca's Area (motor function of speech).

  • Damages to both right and left hemisphere

• Damage causes conduction aphasia

  • Inability to repeat words with intact spontaneous speech production and comprehension.

Adaption

• In perception, a decrease in stimulus perception after a long duration of exposure

  • Stimuli stays same but your perception decreases

• THIS IS A PHYSIOLOGICAL RESPONSE

  • E.g. Body no longer smells odor, thus olfactory neurons reduce firing.

• Learning the process by which new information is processed.

  • Consists of assimilation and accommodation.

Accommodation

Process by which existing schemata are modified to encompass new information.

Opponent-process Theory

• Relates to drug use, addictive behaviors, and self harm

Self-determination Theory

• Broad theory on human motivation and development

Feedback Loop

• Process where the output of a system (like behavior or thought) is fed back as input, influencing subsequent actions or thoughts.

  • Can be (-) or (+)

• There’s a cycle: Action → Feedback → Adjustment → New Action

• Does not

Positive Feedback Loop

• Amplifies a change, leading to further increases or intensification of an effect

Negative Feedback Loop

• Adjusts something e.g. action or behavior to ultimately lead to equilibrium or balance.