The Neuron, Brain, Hormones, Sleep and Consciousness - Flashcards

A comprehensive set of 250 practice flashcards covering neurons, neurotransmitters, brain anatomy and function, sleep, circadian rhythms, and related psychology concepts.

What part of the neuron receives messages from other cells and sends impulses toward the cell body?

Dendrites

Which part of the neuron passes messages away from the cell body to other neurons, glands, or muscles?

Axon

What is the myelin sheath?

A fatty tissue layer that insulates some axons and speeds up transmission; deterioration can impair movement (e.g., in Multiple Sclerosis).

What are terminal branches responsible for?

They end the axon and contain synaptic vesicles that release neurotransmitters.

What is the soma?

The cell body that contains the nucleus and is the life-support center of the neuron.

What are glial cells and what do they do?

Support, nourish, protect neurons; they provide nutrients, insulate myelin, guide connections, and clean up waste.

What triggers the release of neurotransmitters?

An action potential reaching the axon terminals.

Where do neurotransmitters travel to communicate with other neurons?

Across the synapse to receptor sites on the receiving neuron.

What is the synaptic gap?

The junction between the sending neuron’s axon terminal and the receiving neuron.

What is a neurotransmitter?

Chemical messengers that cross synapses between neurons.

What occurs when neurotransmitters bind to receptor sites?

They influence whether the receiving neuron will generate a neural impulse.

How do neurotransmitters cross the synaptic gap?

They travel across the gap and bind to receptor sites on the receiving neuron.

What is the process called when a neuron fires an impulse?

Neural impulse or action potential

What does the 'all-or-nothing' principle mean for neuron firing?

A neuron either fires completely or not at all; there is no partial firing.

What is the threshold in neural firing?

The minimum stimulation required to trigger an impulse.

What is the refractory period?

A brief period after firing during which a neuron cannot fire again.

What is resting potential?

The stable, negative charge of a neuron when it is inactive.

What is depolarization?

Change in membrane potential that makes a neuron more likely to fire.

What is reuptake?

The reabsorption of neurotransmitters by the presynaptic neuron to end the signal.

Which neurotransmitter is involved in reward, motivation, and motor control and is linked to pleasure and addiction at high levels?

Dopamine

Which neurotransmitter regulates mood, sleep, and appetite and is linked to depression when levels are low?

Serotonin

Which neurotransmitter influences alertness and arousal and is high during stress?

Norepinephrine

What is the primary excitatory neurotransmitter involved in learning and memory?

Glutamate

What is the primary inhibitory neurotransmitter that reduces anxiety?

GABA (gamma-aminobutyric acid)

Which neurotransmitters act as natural painkillers and mood enhancers released during exercise?

Endorphins

Which neurotransmitter is involved in pain perception and signals pain to the brain?

Substance P

What is Acetylcholine (ACh) associated with?

Muscle action, learning, memory; deficiencies linked to Alzheimer's; Myasthenia Gravis involves blocked ACh.

What are excitatory messages?

Signals that make the receiving neuron more likely to fire.

What are inhibitory messages?

Signals that make the receiving neuron less likely to fire.

If excitatory signals exceed inhibitory signals and reach threshold, what happens?

An action potential is triggered.

If inhibitory signals cancel out or outweigh excitatory signals, what occurs?

No firing occurs.

What organ system is associated with adrenaline and the fight-or-flight response?

The Endocrine system (via adrenal glands)

What hormone helps regulate energy balance and appetite by signaling fullness?

Leptin

What hormone stimulates appetite and signals the brain to eat?

Ghrelin

Which hormone regulates sleep-wake cycles and promotes sleep?

Melatonin

Which hormone facilitates social bonding and is involved in childbirth and breastfeeding?

Oxytocin

What is the endocrine system?

The body's slow chemical communication system via hormone secretion into the bloodstream.

What gland is considered the master gland of the endocrine system?

Pituitary gland

Which brain area controls the pituitary gland?

Hypothalamus

What is an antagonist drug?

A drug that inhibits or blocks a neurotransmitter’s action (may block reuptake).

What is an agonist drug?

A drug that increases a neurotransmitter’s action or mimics it.

What are psychoactive drugs?

Chemical substances that alter perception and mood—depressants, stimulants, and hallucinogens.

What class is cocaine, and how does it work?

Stimulant; blocks reuptake of dopamine, serotonin, and norepinephrine to create a temporary high.

What is a common stimulant besides cocaine?

Caffeine

What characterizes depressants?

Drugs that slow neural activity and bodily functions.

What are some effects of alcohol on memory and sleep?

Impairs memory; suppresses REM sleep and self-awareness; can cause disinhibition.

What is a barbiturate?

A depressant used to induce sleep or relieve anxiety.

What are opioids and why are they dangerous?

Drugs acting like morphine to relieve pain; highly addictive and can cause overdose.

What is an example of an opioid?

Heroin (and morphine)

What are hallucinogens?

Psychedelics that distort perceptions and evoke sensory images; e.g., marijuana (THC) affects perception.

What is substance use disorder?

Craving and compulsive use despite life disruption or physical risk.

What is tolerance?

Diminished effect with regular use requiring larger doses to achieve the same effect.

What is addiction?

A primary, chronic disease of brain reward, motivation, memory, and related circuitry.

What is withdrawal?

Discomfort and distress following discontinuation of an addictive drug or behavior.

What are the three main divisions of the brain?

Hindbrain, Midbrain, Forebrain

Which structures are in the hindbrain?

Medulla, pons, and cerebellum

What function does the medulla serve?

Regulates essential automatic functions like heart rate, breathing, and blood pressure.

What is the role of the pons?

Bridge between brain regions; involved in sleep regulation.

What is the Reticular Activating System (RAS) responsible for?

Regulates arousal and attention by filtering sensory information.

What brain region acts as the reward center by releasing dopamine?

Reward center (dopamine-related); drives motivation and reinforces behavior.

What does the hypothalamus regulate besides eating and temperature?

Emotion and reward; it works with the pituitary to control endocrine functions.

What does the thalamus do?

Relays sensory information (except smell) to the cortex.

What is the hippocampus responsible for?

Storage of explicit (conscious) memories of facts/events.

What is the amygdala associated with?

Emotion, fear, and aggression processing.

Which brain region is involved in executive functions like planning and decision making?

Prefrontal cortex

What is the role of the frontal lobe?

Motor control, speech, decision making, planning, and executive functions.

What is the occipital lobe responsible for?

Visual information processing.

What is the temporal lobe responsible for?

Auditory processing and language; contains Wernicke’s area.

Where is the parietal lobe located and what does it do?

Back of the brain; processes touch and body position (somatosensory cortex).

What is the frontal lobe’s motor cortex responsible for?

Voluntary movement and motor control.

What is Broca’s area responsible for?

Speech production (left frontal lobe).

What is Wernicke’s area responsible for?

Language comprehension (left temporal lobe).

What happens with Broca’s aphasia?

Nonfluent, labored speech due to left frontal damage.

What happens with Wernicke’s aphasia?

Fluent but nonsensical speech with impaired comprehension.

What is split-brain research useful for illustrating?

How the two hemispheres can operate independently when the corpus callosum is severed.

What is the corpus callosum?

A large band of neural fibers connecting the two hemispheres and enabling communication between them.

What happens if an object is seen in the left visual field in a split-brain patient?

The person may not name it but can draw or point to it with the left hand.

What is contralateral hemispheric organization?

Each hemisphere processes information from the opposite side of the body and opposite visual fields.

What is EEG used for?

Recording electrical activity of the brain via scalp electrodes.

What does fMRI measure?

Blood flow changes to infer brain activity; shows function and structure.

What is the difference between EEG and fMRI?

EEG records electrical activity with high temporal but low spatial resolution; fMRI measures blood flow with good spatial resolution but lower temporal resolution.

What is a case study in brain research?

In-depth analysis of individuals with brain damage to infer function.

What does lateralization of language usually mean?

Language is typically left-dominant in most people.

What is the primary visual cortex?

The initial cortical area to process visual information in the occipital lobe.

What is an association area?

Cortical regions not primarily involved in motor or sensory function; involved in higher mental processes.

What is cerebral cortex?

The thin outer layer of the brain (gray matter) responsible for higher functions.

What is the cerebrum?

The largest part of the brain, containing the cerebral cortex and underlying structures; about 85% of brain weight.

What is epilepsy?

Neurological disorder marked by repeated seizures due to abnormal brain activity.

What is language specialization in the left hemisphere?

Broca’s area for speech production; Wernicke’s area for language comprehension.

What is brain plasticity (neuroplasticity)?

The brain’s ability to change and form new neural connections throughout life.

What is neuroplasticity often observed in?

Musicians, athletes, and others who show structural brain changes related to their skills.

What does EEG reveal about REM sleep?

Rapid eye movements and saw-toothed brain waves indicating brain activity during dreaming.

What are alpha waves and when do they occur?

8–13 Hz waves seen in relaxed wakefulness or at the start of sleep (NREM1).

What are delta waves associated with?

Large, slow waves linked to deep sleep (NREM3 cycles).

How long are typical sleep cycles?

About 90 to 120 minutes, repeating 4–5 times per night.

What happens in NREM-1 sleep?

Light sleep with hypnagogic sensations and possible jerks.

What happens in NREM-2 sleep?

Deeper sleep with sleep spindles and K-complexes; easier to awaken than in NREM-1.

What happens in NREM-3 sleep?

Slow-wave sleep with large delta waves; deepest stage; growth hormones released.

What characterizes REM sleep?

Rapid eye movements; vivid dreams; brain activity similar to wakefulness; muscles paralyzed.

Why is REM sleep called paradoxical sleep?

The brain is active while the body is largely paralyzed.