Lecture Notes Flashcards

Flashcards of terms and definitions from lecture notes.

Osmotic Thirst

Thirst resulting from an increase in the concentration of solutes in the blood, leading to cellular dehydration.

Paraventricular Nucleus (PVN)

A nucleus of the hypothalamus involved in the regulation of various physiological processes, including stress response, metabolism, and water balance.

POMC Neurons

Neurons that produce pro-opiomelanocortin (POMC), a precursor protein that is cleaved to form several important peptides, including α-MSH, which are involved in regulating appetite and energy balance.

PYY3–36

A peptide hormone released by the intestines after eating that reduces appetite by acting on the hypothalamus.

Satiety

The feeling of fullness and the cessation of hunger after eating.

Set Point

The hypothesized optimal value of a physiological parameter, such as body weight or temperature, that the body strives to maintain.

Set Zone

The range within which a physiological parameter can fluctuate without triggering compensatory mechanisms to restore it to the set point.

Subfornical Organ (SFO)

A circumventricular organ in the brain that detects signals related to blood volume and osmolarity, playing a role in the regulation of thirst and fluid balance.

Thermogenin

A protein found in the mitochondria of brown adipose tissue that uncouples oxidative phosphorylation, generating heat instead of ATP.

Thermoregulation

The process by which organisms maintain an optimal internal temperature despite external temperature variations.

Trophic Factor

A protein that supports the growth, survival, and differentiation of developing and mature neurons.

Vagus Nerve

The tenth cranial nerve that interfaces with parasympathetic control of the heart, lungs, and digestive tract.

Vasopressin

Also known as antidiuretic hormone (ADH), it is a hormone that promotes water reabsorption by the kidneys and constricts blood vessels, increasing blood pressure.

Ventromedial Hypothalamus (VMH)

A region of the hypothalamus involved in the regulation of satiety, metabolism, and sexual behavior; lesions in this area can lead to overeating and obesity.

Adenosine

A purine nucleoside involved in cellular energy transfer and signaling. In the context of sleep, adenosine accumulation in the brain promotes sleepiness by inhibiting arousal centers

Alpha Rhythm

A pattern of brainwave activity with a frequency of 8–12 Hz, typically observed during relaxed wakefulness with eyes closed.

Basal Forebrain

A region located at the base of the forebrain, involved in regulating sleep and wakefulness, and implicated in cognitive functions and Alzheimer's disease.

Beta Activity

Brainwave activity with a frequency of 13–30 Hz, associated with active thinking, alertness, and concentration.

Cataplexy

A sudden and transient episode of muscle weakness triggered by strong emotions, often associated with narcolepsy.

Circadian Rhythm

A biological rhythm with a cycle of approximately 24 hours, governing various physiological processes like sleep-wake cycles and hormone release.

Circannual

Referring to biological rhythms that occur on an annual basis, such as seasonal changes in behavior or physiology.

Delta Wave

The slowest type of brainwave, with a frequency of 0.5–4 Hz, characteristic of deep sleep stages (3 and 4) in non-REM sleep.

Desynchronized EEG

Also known as beta activity, it refers to a pattern of EEG activity comprising a mix of many different high frequencies with low amplitude, typically observed during alert wakefulness.

Dimer

A complex formed by two similar molecules (often proteins) that bind together, often to perform a specific biological function.

Diurnal

Active during the daylight hours; organisms that are diurnal are typically awake and active during the day and sleep at night.

Ecological Niche

The role and position a species has in its environment, including how it gets its energy and nutrients, and how it interacts with other organisms.

Electroencephalography (EEG)

The recording of electrical activity along the scalp produced by the firing of neurons within the brain. It is commonly used to study sleep patterns and diagnose neurological disorders.

Electromyography (EMG)

A technique for evaluating and recording the electrical activity produced by skeletal muscles, often used to assess muscle function and diagnose neuromuscular disorders.

Electro-oculography (EOG)

The measurement of the electrical potential between the front and back of the human eye, used to detect eye movements, particularly during sleep studies.

Entrainment

The process by which a biological rhythm becomes synchronized with an external stimulus, such as the light-dark cycle influencing circadian rhythms.

Fatal Familial Insomnia

A rare genetic disorder characterized by progressive insomnia leading to severe mental and physical deterioration, and ultimately death.

Free-running

Referring to a biological rhythm that persists without external cues, often exhibiting a cycle slightly longer or shorter than 24 hours.

General Anesthetic

A substance that induces a reversible loss of consciousness, used during surgical procedures to prevent pain and awareness.

Hypocretins

Also known as orexins, these are neuropeptides produced in the hypothalamus that regulate arousal, wakefulness, and appetite. Deficiencies are associated with narcolepsy.

Infradian

Referring to biological rhythms with a period longer than 24 hours, such as the menstrual cycle.

Isolated Brain

A preparation in which the brain is separated from the rest of the body, often used in research to study brain activity independent of peripheral influences.

Isolated Forebrain

A preparation where the forebrain is isolated from the rest of the brain, allowing researchers to study its functions independently.

K Complex

A large, high-voltage wave observed in the EEG during stage 2 sleep, often in response to external stimuli.

Melanopsin

A photopigment found in certain retinal ganglion cells that are involved in regulating circadian rhythms by detecting ambient light.

Narcolepsy

A sleep disorder characterized by excessive daytime sleepiness, sudden loss of muscle tone (cataplexy), and abnormal REM sleep patterns.

Night Terror

A sleep disorder characterized by sudden arousal from deep sleep, accompanied by intense fear and physiological reactions like rapid heartbeat and sweating. Unlike nightmares, night terrors typically occur during non-REM sleep and the individual often has no memory of the event upon waking.

Nightmare

A vivid and disturbing dream that typically awakens the sleeper, often occurring during REM sleep. Nightmares can cause feelings of fear, anxiety, or sadness and may be linked to stress or trauma.

Nocturnal

Active during the night; organisms that are nocturnal are typically awake and active during the night and sleep during the day.

Non-REM (NREM) Sleep

A phase of sleep characterized by slower brain waves and the absence of rapid eye movements. It includes stages 1 through 3, with deep sleep occurring in stages 3 and 4.

Paradoxical Insomnia

A condition where individuals perceive themselves as having poor sleep quality or quantity despite evidence of normal sleep patterns.

Period

The duration of one complete cycle of a biological rhythm.

Phase Shift

A shift in the timing of a biological rhythm, often in response to external cues like light or temperature.

Pineal Gland

A small endocrine gland in the brain that produces melatonin, a hormone that regulates sleep- wake cycles.

Rapid-Eye-Movement (REM) Sleep

A phase of sleep characterized by rapid movement of the eyes, increased brain activity, and vivid dreams. REM sleep is thought to play a role in memory consolidation and mood regulation.

REM Behavior Disorder (RBD)

A sleep disorder where individuals act out vivid dreams during REM sleep, potentially leading to injury. It is often associated with neurodegenerative diseases.

Reticular Formation

A network of neurons located in the brainstem that plays a crucial role in regulating arousal, attention, and sleep-wake cycles.

Retinohypothalamic Pathway

The neural pathway that transmits light information from the retina to the hypothalamus, particularly to the suprachiasmatic nucleus, helping to regulate circadian rhythms.

Sleep Apnea

A sleep disorder characterized by pauses in breathing or periods of shallow breathing during sleep, leading to disrupted sleep and potential health issues.

Sleep Cycle

A complete progression through the various stages of sleep, including NREM and REM stages. A typical sleep cycle lasts about 90 minutes and repeats several times throughout the night.

Sleep Deprivation

The condition of not getting enough sleep, which can impair cognitive function, mood, and overall health.

Sleep Enuresis

Also known as bed-wetting; the involuntary urination during sleep, most common in children but can also affect adults.

Sleep Hygiene

Practices and habits that promote consistent, uninterrupted sleep, such as maintaining a regular sleep schedule and creating a comfortable sleep environment.

Sleep Paralysis

A phenomenon where an individual temporarily experiences an inability to move or speak while falling asleep or waking up, often accompanied by vivid hallucinations

Sleep Recovery

The process of compensating for lost sleep by sleeping more than usual, which can help restore cognitive function and mood.

Sleep Spindle

A sudden increase in wave frequency in the brain's electrical activity that occurs most commonly during NREM sleep, particularly in stage 2.

Sleep-Maintenance Insomnia

Difficulty staying asleep throughout the night, often leading to waking up too early and being unable to fall back asleep.

Sleep-Onset Insomnia

Difficulty falling asleep at the beginning of the night, often due to stress or anxiety.

Slow-Wave Sleep (SWS)

Also known as deep sleep, it is characterized by slow brain waves and is considered restorative for the body and mind.

Somnambulism

Commonly known as sleepwalking; a behavior disorder that involves walking or performing other complex behaviors while asleep.

Stage 1 Sleep

The lightest stage of NREM sleep, where the individual transitions from wakefulness to sleep, characterized by slow eye movements and muscle relaxation.

Stage 2 Sleep

A deeper stage of NREM sleep, marked by sleep spindles and K-complexes, which are thought to play a role in memory consolidation.

Stage 3 Sleep

Also known as deep NREM sleep, characterized by slow delta waves; it is the most restorative stage of sleep.

Subcoeruleus

A region in the brainstem that is active during REM sleep and is thought to play a role in regulating REM sleep and muscle atonia.

Sudden Infant Death Syndrome (SIDS)

The unexplained death of an infant, typically during sleep, that remains unexplained after thorough investigation.

Suprachiasmatic Nucleus (SCN)

A small region in the hypothalamus that serves as the primary circadian pacemaker, regulating the body's internal clock and sleep-wake cycles.

Tuberomammillary Nucleus

A group of histaminergic neurons in the hypothalamus that play a role in promoting wakefulness and regulating sleep.

Ultradian

Referring to biological rhythms that have a period shorter than 24 hours, such as the cycles of REM and NREM sleep.

Vertex Spike

A sharp wave that appears at the vertex of the scalp during the EEG of individuals in stage 1 sleep, often associated with the transition from wakefulness to sleep.

Zeitgeber

A German term meaning "time giver"; external cues, like light, that help synchronize the internal biological clock to the 24-hour day.

Adrenal Cortex

The outer layer of the adrenal glands, responsible for producing steroid hormones such as cortisol, aldosterone, and androgens.

Adrenal Medulla

The inner part of the adrenal glands that produces catecholamines, including epinephrine and norepinephrine, which are involved in the body's stress response.

Adrenal Steroids

Hormones produced by the adrenal cortex, including glucocorticoids (e.g., cortisol), mineralocorticoids (e.g., aldosterone), and androgens, which regulate various physiological processes.

Aggression

Behavior intended to cause harm or pain, which can be physical or psychological, and may be influenced by genetic, environmental, and social factors.