biology of psych, unit 2

dumb brain stuff

Biological perspective

The psychological approach explaining behavior and thoughts through genetics, brain structures, and biochemical processes

Endocrine system

our body’s communication systems, controlling mood, development, and reproduction. Process: glands pushing chemicals into our bloodstream.

Hormones

Chemical messengers released by glands in the endocrine system that regulate various bodily functions and behaviors.

Pituitary gland (growth)

in our brain, controls production and distribution of all hormones in endocrine. it is called “master gland”. it has a growth hormone called oxytocin encouraging connection, love feelings, trust, and happiness.

Pineal gland (melatonin)

deep inside our brain, controls sleep cycle. has hormone called melatonin, which releases in the darkness to make us tired.

Thyroid (thyroxin)

in our neck, turns food into energy. has hormone thyroxin, controls metabolism rate. (how fast your body burns calories) (energy)

Pancreas (insulin)

behind your stomach, controls blood sugar. has hormone insulin, which lets cells use blood sugar for energy or store it for later.

adrenal glands (epinephrine, cortisol)

on top of kidneys, controls response to stress. has hormone cortisol, epinephrine, stress hormones that control fight of flight. (heart rate, breathing, alertness)

Central nervous system (CNS)

The part of the nervous system that includes the brain and spinal cord, responsible for processing information and coordinating body functions.

peripheral nervous system (PNS)

The part of the nervous system that lies outside the central nervous system, consisting of sensory and motor neurons that connect the CNS to the rest of the body.

Somatic nervous system

a part of the peripheral nervous system that controls voluntary movements by transmitting signals from the brain to skeletal muscles.

Autonomic nervous system

The peripheral division regulating involuntary visceral operations like heart rate, respiration, and digestion.

Sympathetic nervous system

The autonomic branch activating the fight-or-flight response, accelerating pulse and pausing digestion during threats.

Parasympathetic nervous system

The autonomic branch calming the body after danger, promoting resting, digestion, and energy preservation

Neuron

A specialized cell that receives, processes, and transmits electrical and chemical information.

sensory/afferent neuron

Nerves carrying incoming sensory input from physical receptors inward toward the central nervous system.

motor/efferent neuron

Nerves carrying outgoing movement instructions from the central nervous system outward to muscles and glands.

Interneurons

 Central nervous system connecting cells that relay messages between incoming sensory and outgoing motor paths.

Reflex

An automatic, rapid physical response to a stimulus mediated by an isolated spinal loop before brain perception.

Dendrite

 Branching extensions of a nerve cell that capture and receive incoming signals from neighboring cells.

Soma (cell body)

The structural center of a nerve cell containing the nucleus, sustaining cellular health and integrating inputs.

Nucleus

The central organelle inside the nerve cell body housing genetic blueprints and directing cellular operations.

Axon

A long, slender nerve fiber transmitting electrical action potentials away from the cell body toward target cells.

Myelin sheath

A fatty insulating layer encasing axons that greatly accelerates electrical impulse transmission speed.

Terminal branches (“axon terminals”)

The branching endpoints of an axon that reach toward adjacent cells to form communication junctions.

Terminal buttons

Swollen knobs at axon branch tips containing vesicles that release chemical messengers into the synaptic gap.

Multiple sclerosis

An autoimmune condition where the body attacks and degrades the myelin sheath, disrupting neural transmission.

Myasthenia gravis

A neuromuscular disorder where antibodies block muscle receptors from receiving acetylcholine, creating extreme fatigue.

Resting potential

The baseline negative electrical charge of an inactive neuron awaiting activation, typically around -70 mV.

Polarization

The resting electrical state where the inside of a cell membrane maintains a net negative charge relative to the outside.

Depolarization

 The initial rush of positive sodium ions across the membrane that cancels and reverses the negative resting charge.

Threshold

The minimum level of excitatory stimulation required to trigger an electrical action potential (around -55 mV).

All-or-none principle

 The biological rule stating that a nerve impulse fires completely at maximum strength or not at all.

Action potential

 A brief electrical wave of positive charge sweeping down an axon once triggered by sufficient stimulation.

Refractory period

 A brief recovery interval following an impulse during which a neuron cannot fire again until resting ions reset.

Sodium-potassium pump

 A membrane transport mechanism that exports three sodium ions and imports two potassium ions to re-establish resting balance.

Repolarization

The exit of positive potassium ions from the cell to restore the resting negative internal charge.

Excitatory neurotransmitters

Chemical messengers that pushes the likelihood of the receiving neuron reaching its firing threshold.

Inhibitory neurotransmitters

Chemical messengers that STOPS the recieving neuron firing.

Acetylcholine

 A neurotransmitter that facilitates skeletal muscle contraction, voluntary motion, learning, and memory.

Glutamate

The primary excitatory chemical messenger in the central nervous system, fundamental for synaptic plasticity and memory.

Serotonin

A chemical messenger that regulates mood stability, appetite, sleep rhythms, and emotional well-being

Norepinephrine

A chemical messenger that heightens physical alertness, vigilance, and heart rate during stressful situations.

Dopamine

A chemical messenger governing motivation, reward reinforcement, pleasure sensations, and smooth motor control.

GABA

The principal inhibitory chemical messenger that calms neural activity to alleviate anxiety.

Gate-control theory

The model proposing that a neurological gate in the spinal cord can open to pass pain or close to block it, letting Substance P in and pushing endorphins out.

Synapse

The microscopic fluid gap across which chemical signals travel between communicating nerve cells.

Reuptake

The reabsorption of unspent chemical messengers back into the sending terminal button after transmission.

Computer tomography (CT) scan

Takes x-rays from many angles and helps identify large structures Ex: tumors

magnetic resonance imaging (MRI) scan

Uses strong magnetic energy to create a more detailed image of the brain

Electroencephalogram (EEG)

places electrodes on scalp to measure brains electrical activity. (used in seizures / sleep studies)

Positron emission tomography (PET) scan

injects person w/ radioactive glucose, then traces where it goes while person performs mental action. wherever glucose is consumed, that’s the brain part used.

Functional magnetic resonance imaging (fMRI) scan

combines MRI + PET detects where oxygen is carried, locks out blood flow + compares MRI scans. not used as often.

Brainstem

The oldest structural region at the brain's base that manages automatic, life-sustaining functions.

Medulla oblongata

The lowest brainstem structure controlling vital involuntary reflexes including heart rate, respiration, and blood pressure.

Pons

A brainstem structure above the medulla that coordinates motor messages, facial expressions, and sleep-wake cycles

Reticular activating system

A brainstem nerve network that filters sensory data and regulates physiological arousal, vigilance, and waking.

Reward center

A dopamine-fueled limbic pathway that reinforces behaviors vital for pleasure, motivation, and survival.

Thalamus

The sensory switchboard that receives and directs incoming sensory inputs (excluding smell) to appropriate brain parts.

Cerebellum

The rear brain structure governing voluntary balance, motor coordination, and rhythm. effected by alcohol.

Limbic system

A ring of interconnected structures including the hippocampus and amygdala governing emotions, drives, and memory.

Hippocampus

 A limbic structure essential for processing and consolidating conscious explicit memories and facts into permanent storage.

Amygdala

Almond-shaped limbic clusters that regulate emotional responses, particularly fear, anger, and threat detection.

Hypothalamus

 A master control center beneath the thalamus that regulates internal homeostasis, drives (hunger, thirst), and the endocrine system.

Olfactory bulb

The brain structure receiving scent information directly from the nasal cavity.

Cerebral cortex

The wrinkled outer mantle of the brain responsible for complex thinking, sensory analysis, and voluntary control.

Association areas

part of the cerebral cortex. they integrate both sensory and motor information to carry out advanced reasoning, judgement, and planning. they are widespread across the brain.

Frontal lobe

The forward cortical region managing higher level cognitive functions, decision-making, morality, personality, and speech.

Prefrontal cortex

The tip of the frontal lobe that governs future planning, working memory, social reasoning, and impulse control.

Parietal lobe

The top-middle cortical lobe that processes touch sensations (pain, pressure), and spacial awareness.

Occipital lobe

helps receiving and processing visual information from your eyes.

Temporal lobe

helps auditory processing and speech comprehension.

Motor cortex

A strip along the frontal lobe that transmits signals to produce voluntary body motion.

Sensory cortex

a strip along the parietal lobe that registers incoming tactile touch, pressure, and temperature data.

Broca’s areas

A left frontal region responsible for controlling muscle actions required to use ur spoken language. (mouth moving, tongue movement)

Wernike’s area

A left temporal region responsible for comprehending spoken language, and forming actual sentences.

Contralateral control

the pattern of how each brain hemisphere is controlled and operates each brain hemisphere. The left operates the right side, and the right operates the left. (left hemisphere = right hand)

Neural networks

interconnected clusters of neurons that strengthen through repeated actions / collaborations. they work together to adapt your brain.

Plasticity

the brains ability to change, and adapt it’s functions and structures throughout life. even if u experience critical damage.

Long-term potentiation (LTP)

connections adapting. the more you do something, the stronger the neural network. information travels faster and more efficiently by training the synapse.

Glial cells

Supportive nervous system cells that insulate, nourish, repair, and clear waste around active neurons.

Neurogenesis

The biological process wherein new functional neurons are birthed and developed in the brain.

Corpus callosum

The thick bundle of nerve fibers bridging the two brain hemispheres to allow continuous cross-communication. 

Hemisphere lateralization

The division of the two brain hemispheres, predominantly into either the left or right hemisphere. each side specializes in something specific. (left = logic, right = creativity etc)

Split-brain research

Studies on patients with a severed corpus callosum, demonstrating that each hemisphere can operate independently. 

Substance P

Excitatory, sends pain signals to your brain.

Endorphins

Inhibitory, stops pain signals. Body’s natural pain killer. Too much = runner’s high