Hormones

Adrenaline

A hormone released from the adrenal glands that increases heart rate and blood pressure in times of stress

ASC (altered state of consciousness)

Any state that is characteristically different from normal waking consciousness in terms of awareness, feelings and behaviours.

Amplitude

The height of a wave above or below the equilibrium line. It indicates how intense the wave is.

Biological rhythm

A repeated biological process that is regulated by internal mechanisms

Circadian rhythm

A biological rhythm based on a 24 hour period

DSPS (delayed sleep phase syndrome)

A condition where the internal circadian rhythm is delayed two hours or more from a conventional sleep pattern, despite external cues such as night falling.

EEG (electroencephalograph)

A measure of the electrical of the brain (brain waves), used to identify sleep stages such as REM and NREM

EMG (electromyograph)

A measure of the electrical activity of muscles, used to measure muscles tension

Endocrine system

A system that allows cells in the body to communicate. Endocrine glands secrete hormones that travel in the blood for internal communication and regulation.

EOG (electrooculograph)

A measure of the electrical activity of eye muscles, used to detect eye movements

Fight - Flight - Freeze response

A response triggered when a threat is detected, causing changes in the body as nerves hormones prepare the body for confrontation, escape or avoiding detection

Frequency

The number o vibrations or waves made in one second

Glucagon

A hormone produced by specialised cells in the pancreas that causes the liver to break down stored glycogen into glucose, which is released into the blood stream to increase blood glucose levels

Homeostasis

The maintenance of a constant internal environment

Hormone

A chemical messenger produced by an endocrine gland and released into the bloodstream, which travels to a target cell or tissue where it produces a specific response

Hypnogram

A graph showing the stages of sleep and awakenings during a sleep episode

Hypothalamus

A part of the brain that monitors internal systems and coordinates the nervous and endocrine systems to maintain homeostasis

Insulin

A hormone produced by specialised cells in the pancreas that causes cells to take up glucose from blood and store it as glycogen, helping to lower blood glucose levels.

Melatonin

A hormone that is secreted during low levels of light. It helps to synchronise internal events to external cues and makes us feel sleepy when light levels decrease

Negative feedback

A feedback process where the response goes in the opposite direction to the change, bringing things back to normal and helping keep body variables within a set range

NWC (normal waking consciousness)

Awareness of your thoughts, feelings and behaviours, including internal and external events.

NREM Sleep

Non rapid eye movement sleep. It includes three stages ranging from light sleep to deep sleep

Parasympathetic nervous system

The part of the autonomic nervous system that calms the body down after danger and helps return the body to normal.

Positive feedback

A feedback process where the response goes in the same direction as the stimulus, making the change bigger until the stimulus stops

Receptor

A structure that detects changes or variations (stimuli) in the internal environment and helps communicate that a response is required

REM sleep

A type of sleep characterised by rapid eye movement, high levels of brain activity and low levels of physical activity.

Sleep episode

The total time spent asleep

Sleep hygiene

The healthy habits and behaviours that can be engaged in to improve the onset and quality of sleep.

Stimulus

A change or variation in the internal environment that needs to be detected and may require a response

Sympathetic nervous system

The part of the autonomic nervous system that switches the body on for action

Target cell

A cell that has a specific receptor that is complementary in shape to a particular hormone, allowing the hormone to bind and trigger a response.

Ultradian rhythm

A physical, mental or behavioural pattern is repeated within cycles lasting less than 24 hours. A sleep cycle is an example