Psych 110 exam 2

DNA

A complex molecule containing the genetic information that makes up the chromosomes. It is the blueprint for life, carrying instructions for the development, functioning, growth, and reproduction of all known organisms.

Chromosomes

Thread-like structures made of DNA molecules that contain the genes. Humans typically have 23 pairs of chromosomes (46 total) in most body cells.

Genes

The biochemical units of heredity that make up the chromosomes; a segment of DNA capable of synthesizing a protein. They are specific sequences of nucleotides that code for particular traits or functions.

Natural Selection

The evolutionary process by which heritable traits that best enable organisms to survive and reproduce in particular environments are passed to succeeding generations. "Survival of the fittest."

Genotype

An organism's complete set of genetic instructions, its genetic makeup. This refers to the specific genes an individual possesses.

phenotype

An organism's observable characteristics or traits, such as its physical characteristics (e.g., eye color, height), behavioral traits, or psychological characteristics. This is the expression of the genotype influenced by environmental factors.

Alleles

Different forms of a gene. For example, a gene for eye color might have an allele for blue eyes and an allele for brown eyes. Individuals inherit two alleles for each gene, one from each parent.

genotype v phenotype

Genotype is the inherited genetic makeup (the blueprint), while phenotype is the observable expression of those genes, influenced by both genetic and environmental factors (the observable trait).

evolutionary theory

Proposed by Charles Darwin, it suggests that species change over time through the process of natural selection. This theory explains the diversity of life on Earth by proposing that all life shares a common ancestor and has diverged over geological timescales.

23 pairs, 46

Bodily cells contain _ _ of chromosomes, totaling _ chromosomes. Each chromosome is composed of tightly coiled DNA.

23 individual

Egg and sperm (gametes) contain half the number of chromosomes, specifically _ _ chromosomes (not pairs). This ensures that when an egg and sperm fuse during fertilization, the resulting zygote has the correct total of 46 chromosomes.

cell body (soma)

The neuron's life-support center. It contains the nucleus and other organelles, carrying out metabolic functions to keep the neuron alive and functional. It integrates incoming signals.

dendrites

branching extensions that receive messages from other neurons and conduct them toward the cell body. They are the primary receptive surface of the neuron.

axon

a long, thin extension of a neuron that transmits electrical impulses away from the cell body to other neurons, muscles, or glands. It is essential for communication in the nervous system and can be covered with myelin to increase speed.

myelin sheath

A fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one node to the next.

glial cells

what produces the myelin sheath?

axon terminal

• The endpoint of an axon, where the axon branches out into numerous fine extensions.

terminal buttons

Small knobs at the end of the axon terminals that contain synaptic vesicles. They are responsible for transmitting signals across the synapse. These structures release neurotransmitters into the synaptic cleft.

synaptic vesicles 

Sac-like structures within the terminal buttons that store neurotransmitters. When an action potential arrives, these vesicles release neurotransmitters into the synapse.

synapse

The junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. The tiny gap at this junction is called a cleft. Neurotransmitters cross this gap to transmit signals.

neural communication

Neurons communicate through an electrochemical process. Electrical signals (action potentials) travel within a neuron, and chemical signals (neurotransmitters) transmit information between neurons across the synapse.

resting potential

The neuron's normal state when not firing, maintained by a slightly negative charge inside the axon membrane (due to the action of the Na+/K+ pump, which pumps out more Na+ ions than it pumps in K+ ions). The membrane is polarized.

depolarization (threshold reached)

If a neuron receives sufficient excitatory input, the membrane potential reaches a threshold. This triggers the opening of voltage-gated Na+ channels.

rising phase (action potential firing)

Na+ ions rush into the axon, making the inside of the membrane positively charged relative to the outside. This rapid change in voltage is the action potential.

repolarization

Voltage-gated Na+ channels close, and voltage-gated K+ channels open, allowing K+ ions to rush out of the cell. This restores the negative charge inside the axon.

hyperpolarization (undershoot)

K+ channels close slowly, causing a brief period where the membrane potential becomes even more negative than the resting potential before returning to rest. This is known as the refractory period, during which the neuron cannot fire another action potential.

Role of neurotransmitters in the action potential

Neurotransmitters are chemicals released at synapses that bind to receptors on the postsynaptic neuron, influencing whether it will generate an action potential by exciting or inhibiting neural activity.

dopamine

Involved in reward, motivation, pleasure, motor control, and voluntary movement.

dopamine

Dysregulation is linked to Parkinson's disease (low) and schizophrenia (high)

acetylcholine

Plays a crucial role in muscle contraction (at the neuromuscular junction), learning, memory, and attention.

acetylcholine

Low levels are associated with Alzheimer's disease.

norepinephrine

Involved in alertness, arousal, mood regulation, and the "fight-or-flight" response (stress).

norepinephrine

Low levels may contribute to depression and ADHD

serotonin

Affects mood, hunger, sleep, and arousal

serotonin

Imbalances are associated with depression, anxiety, and obsessive-compulsive disorder.

GABA

The primary inhibitory neurotransmitter in the brain. It slows down brain activity, reducing anxiety and promoting relaxation.

GABA

Low levels are linked to anxiety disorders and seizures.

glutamate

The primary excitatory neurotransmitter in the brain. Involved in learning and memory formation.

glutamate

High levels can lead to overstimulation, potentially causing migraines or seizures.

beta endorphin

Natural opioid-like neurotransmitter that reduces pain and promotes feelings of euphoria and well-being. Involved in the body's natural pain relief system.

somatic nervous system

Part of the peripheral nervous system responsible for voluntary control of skeletal muscles and conveying sensory information from the body to the brain.

afferent nerve fibers (sensory neurons)

Carry sensory information (e.g., touch, pain, temperature, pressure) from sensory receptors in the body (skin, muscles, organs) to the central nervous system (brain and spinal cord). They are responsible for sensation.

efferent nerve fibers (motor neurons)

Carry motor commands from the central nervous system to the skeletal muscles, initiating voluntary movement. They are responsible for movement.

brain (CNS)

The control center, responsible for thought, emotion, perception, memory, and movement. It processes sensory information, regulates body functions, and initiates responses.

spinal cord (CNS)

A long, thin, tubular bundle of nervous tissue and support cells that extends from the brain. It transmits signals between the brain and the rest of the body (via peripheral nerves) and controls simple reflexes.

peripheral nervous system (PNS)

Connects the CNS to the rest of the body, including organs, muscles, and glands. It carries sensory information to the CNS and motor commands from the CNS.

somatic nervous system (PNS)

Controls voluntary movements of skeletal muscles and transmits sensory information to the CNS. (As described above, uses afferent and efferent fibers).

autonomic nervous system (PNS)

Controls involuntary bodily functions such as heart rate, digestion, respiration, pupil dilation, and glandular activity. It operates largely outside conscious awareness. includes the sympathetic and parasympathetic subdivisions that regulate the body's response to stress and relaxation.

sympathetic nervous system (ANS)

Arouses the body, mobilizing its energy in stressful situations (e.g., "fight-or-flight" response). It increases heart rate, dilates pupils, inhibits digestion, and redirects blood flow to muscles.

parasympathetic nervous system (ANS)

Calms the body, conserving its energy, and returning it to a resting state (e.g., "rest-and-digest"). It decreases heart rate, constricts pupils, stimulates digestion, and promotes general relaxation. These two systems often work in opposition to maintain homeostasis.

corpus callosum

The brain is divided into left and right hemispheres, connected by the _ _.

left hemisphere

Hemisphere typically dominant for language, logic, analytical tasks, and sequential processing.

right hemisphere

Hemisphere typically dominant for spatial reasoning, creativity, facial recognition, emotional processing, and holistic processing.

forebrain

The largest and most complex part of the brain, containing the cerebral cortex, thalamus, hypothalamus, and limbic system. Responsible for higher-level cognitive functions, sensory processing, and regulation of vital functions.

hindbrain

Located at the base of the brain, it contains the cerebellum, pons, and medulla. Responsible for vital bodily functions, balance, coordination, and sleep.

midbrain

Located between the forebrain and hindbrain. Involved in relaying visual and auditory information, motor control, and sleep/wake cycles.

Lobe of the cerebral cortex located at the front of the brain. Involved in executive functions, planning, decision-making, personality, voluntary movement, and speech production (Broca's area). The prefrontal cortex in particular is crucial for working memory, attention, problem-solving, and social behavior.

temporal lobe

Lobe of the cerebral cortex located below the frontal and parietal lobes, near the temples. Involved in auditory processing, memory formation, facial recognition, and language comprehension (Wernicke's area).

parietal lobe

Lobe of the cerebral cortex located at the top rear of the brain. Processes sensory information such as touch, temperature, pain, and pressure (somatosensory cortex). Involved in spatial awareness and navigation.

occipital lobe

Lobe of the cerebral cortex located at the back of the brain. Involved in processing visual information and integrating visual data with other sensory inputs.

wernicke’s area

Crucial for language comprehension. Damage leads to receptive aphasia (difficulty understanding spoken language). Located in the left temporal lobe.

Crucial for language production and articulation. Damage leads to expressive aphasia (difficulty producing coherent speech). Located in the left frontal lobe

cerebellum

Located at the rear of the brainstem, involved in voluntary movement, balance, coordination, posture, and motor learning. Often called the "little brain."

thalamus

Located at the top of the brainstem, deep within the brain. It is the brain's sensory control center, relaying all sensory information (except smell) to the appropriate areas of the cerebral cortex for processing. Also involved in sleep and wakefulness.

hypothalamus

Located below the thalamus. Regulates vital functions such as hunger, thirst, body temperature, sexual behavior, and endocrine system activity (by controlling the pituitary gland). Key for maintaining homeostasis.

somatosensory cortex

Located in the parietal lobe, directly behind the motor cortex. Processes bodily sensations such as touch, temperature, pain, and pressure. Different areas of the cortex correspond to different parts of the body, with more sensitive areas (e.g., fingertips, lips) having larger cortical representations.

right motor cortex

Located in the frontal lobe, controls voluntary movements of the left side of the body.

left motor cortex

Located in the frontal lobe, controls voluntary movements of the right side of the body.

reticular formation

A nerve network that extends from the spinal cord right up through the thalamus. Filters incoming sensory stimuli and relays important information to other brain areas, playing a crucial role in arousal, sleep, and consciousness.

subcortical structures

medulla, pons, limbic system (amygdala and hippocampus) (structure located beneath the cerebral cortex)

medulla (part of the brain stem)

Located at the base of the brainstem, controls essential involuntary life-sustaining functions such as heartbeat, breathing, blood pressure, and digestion.

pons (part of the brainstem)

Located above the medulla. Helps coordinate movements (especially facial expressions and eye movements), sleep, and arousal. Relays information between the cerebellum and the cerebral cortex.

limbic system (amygdala & hippocampus)

a collection of structures involved in emotion, motivation, memory, and learning.

amygdala

Two limbic system pea-sized clusters linked to emotion, particularly fear and aggression. Important for processing emotional memories.

hippocampus

A structure in the limbic system linked to the formation of new memories (facts and events). Its name comes from its seahorse-like shape.

brain lateralization

Refers to the tendency for some neural functions or cognitive processes to be specialized to one side of the brain or the other. While both hemispheres work together, specific functions are often primarily handled by one side.

contralateral control

A key aspect of lateralization, particularly for motor and sensory functions. For example, the left cerebral hemisphere (including the left motor cortex) controls the movements and processes sensory input from the right side of the body, and the right cerebral hemisphere (including the right motor cortex) controls the movements and processes sensory input from the left side of the body. This cross-over generally occurs at the level of the brainstem or spinal cord.

endocrine system

The body's "slow" chemical communication system; a set of glands that secrete hormones into the bloodstream.

hormones

Chemical messengers produced by endocrine glands that travel through the bloodstream and affect other tissues, including the brain. They regulate various bodily processes such as growth, metabolism, mood, reproduction, and stress responses.

role of endocrine system

Works in parallel with the nervous system to maintain homeostasis and regulate long-term processes. It influences many aspects of behavior and physiology, often slower but with longer-lasting effects than neural communication. Key glands include the pituitary, thyroid, adrenal, pancreas, and gonads.

neuroplasticity

The brain's remarkable ability to reorganize itself by forming new neural connections throughout life, or by strengthening or weakening existing ones. This allows the brain to adapt, learn, recover from injury, and develop new skills by constantly modifying its structure and function in response to experience, learning, or damage.

fMRI

A neuroimaging technique that measures brain activity by detecting changes in blood flow. When an area of the brain is more active, it requires more oxygenated blood. The fMRI detects the changes in magnetic properties of oxygen-rich blood, thus showing which brain regions are active during specific mental tasks.

purpose of fMRI

the _ _ _ : A neuroimaging technique that measures brain activity by detecting changes in blood flow. When an area of the brain is more active, it requires more oxygenated blood. The fMRI detects the changes in magnetic properties of oxygen-rich blood, thus showing which brain regions are active during specific mental tasks.

sensation

The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment. It's the raw physical input from the world interpreted by our senses (e.g., light waves, sound waves, pressure, chemicals).

perception

The process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events. It's how our brain makes sense of the raw sensory data, involving interpretation, selection, and organization of sensations. Sensation is bottom-up (data-driven), while perception is a combination of bottom-up and top-down (knowledge-driven).

transduction

The process of converting one form of energy into another. In sensation, it's the conversion of physical stimulus energy (like light waves or sound waves) into neural impulses that the brain can understand.

the retina

where does transduction occur in the eye?

the cochlea

where does transduction occur in the ear?

nerve endings

where does transduction occur for touch?

the taste buds

where does transduction occur for the sense of taste?

the olfactory bulb

where does transduction occur for the sense of smell?

bottom up processing

Analysis that begins with the sensory receptors and works up to the brain's integration of sensory information. It is data-driven, focusing on the raw features of the stimulus (e.g., recognizing a face by first detecting individual features like eyes, nose, mouth).

top down processing

Information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations. It is conceptually driven, using existing knowledge to interpret sensory input (e.g., recognizing a familiar face at a distance based on overall shape and context, even if individual features aren't perfectly clear).

rods

Purpose: Detect black, white, and gray; necessary for peripheral and twilight vision when cones don't respond. They are primarily responsible for vision in low light conditions (scotopic vision).

Location: More numerous (about 120 million per eye), primarily found in the periphery of the retina. They are sensitive to dim light but do not discern color or fine detail.

cones

Purpose: Function in daylight or well-lit conditions. They detect fine detail and give rise to color sensations (photopic vision).

Location: Less numerous than rods (about 6 million per eye), mostly clustered in the fovea (the central focal point of the retina), which provides sharpest vision. Different types of cones are sensitive to different wavelengths of light (red, green, blue).

trichromatic theory

The theory that the retina contains three different color receptors—one most sensitive to red, one to green, one to blue—which, when stimulated in combination, can produce the perception of any color. This theory explains color vision at the level of the cones in the retina.

opponent process theory

The theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision. For example, some cells are stimulated by green and inhibited by red; others are stimulated by red and inhibited by green. This theory explains why we see afterimages and why some color combinations (like "reddish-green") seem impossible. This processing occurs in the ganglion cells of the retina and the neurons in the thalamus. These two theories are not mutually exclusive; color vision typically begins with trichromatic processing in the cones and then shifts to opponent-process processing as signals move to higher levels of the visual system.

absolute threshold

The minimum stimulation needed to detect a particular stimulus 50% of the time. It is the faintest detectable stimulus (e.g., the minimum volume of a sound you can hear, or the dimmest light you can see).

difference threshold (just noticeable difference)

The minimum difference between two stimuli required for detection 50% of the time. It is the smallest noticeable change in a stimulus (e.g., how much brighter a light needs to be before you notice a change, or how much louder a sound needs to be).

just noticeable difference

Synonymous with the difference threshold. It refers to the smallest detectable change in a stimulus. Ernst Weber's Law states that for an average person to perceive a difference, two stimuli must differ by a constant minimum percentage or proportion, not a constant amount (\Delta I / I = K where \Delta I is the JND, I is the initial stimulus intensity, and K is a constant for a particular sense).