Acetylcholine was the first neurotransmitter to be discovered and is found primarily at sites throughout the nervous system. It is responsible for the transfer of information between nerve and muscle, either triggering or stopping the contraction of muscle. ... Read more

Adrenal glands

The adrenal glands are two glands located at the top of each kidney, composed of two distinct parts: the adrenal cortex and the adrenal medulla. The adrenal cortex produces vital hormones such as cortisol, DHEA and testosterone; and is also part of the ... Read more


Adrenaline, also known as epinephrine, is primarily a hormone. The amino acids phenylalanine and tyrosine are precursors to noradrenaline, which is then converted into adrenaline in the adrenal medulla (part of the adrenal glands). Small amounts are ... Read more


The amygdala forms part of the limbic system. It is composed of two small almond-shaped structures and is larger in men than women. It plays a primary role in our emotional responses, including feelings like pleasure, fear, anxiety and anger; but also ... Read more

Anterior cingulate cortex

The anterior cingulate cortex is the part of the brain with connections to both the limbic system and the prefrontal cortex. It is sometimes called the “neural alarm system” as it is responsible for emotional regulation and processing.Stevens, F. ... Read more


Brain-derived neurotrophic factor (BDNF) is a protein found at the connections between nerves in the brain and spinal cord. It is essential for the survival of neurons as it plays an important role in their growth, maturation, maintenance and regeneration; ... Read more

Blood-brain barrier

The blood-brain barrier (BBB) is a protection barrier which regulates the passage of compounds from the blood to the brain. It protects the brain and contributes to its homeostasis.Ballabh, P., Braun, A. and Nedergaard, M., 2004. The blood–brain barrier: ... Read more

Central nervous system

The central nervous system (CNS) is one of the main sections of the nervous system, made up of the nerves in the brain and spinal cord. It is referred to as "central" because it combines information from the entire body’s nerves and coordinates activity ... Read more

Cerebral cortex

The cerebral cortex is the outermost layer of the brain which gives it the wrinkly appearance. It is divided into four lobes - the frontal lobe, parietal lobe, occipital lobe, and temporal lobe.Queensland Brain Institute. (2018). Lobes of the brain. ... Read more


Cortisol is a steroid hormone released in greatest quantities when we wake up in the morning and during times of stress. In times of stress, it’s production is controlled by the hypothalamus, pituitary and adrenal glands through the HPA axis. Cortisol ... Read more


Dehydroepiandrosterone (DHEA) is a steroid hormone, mainly produced in the adrenal glands. It functions as a precursor to male and female sex hormones, including testosterone and estrogen.WebMD. (n.d.). DHEA Supplements: Uses and Side Effects. [online] ... Read more


Dopamine is an inhibitory neurotransmitter that is essential in controlling the brain’s reward and pleasure centres, and therefore plays a huge role in the development and maintenance of addictions. It can function as both inhibitory and excitatory, ... Read more

Endocrine system

The endocrine system is the collection of glands that produce and release hormones. It is made up of the pituitary, thyroid, and adrenal, and the pancreas, ovaries (in females) and testicles (in males).Zimmermann, K. (2018). Endocrine System: Facts, ... Read more


Endorphins are are often called "feel-good" chemicals, as they relieve pain and stress and produce a “high” feeling. They are made primarily by the hypothalamus and pituitary gland and work by binding to the opioid receptors in our brain, much like ... Read more


Estrogen is the female sex hormone responsible for female sexual and reproductive development, although men also have estrogen in small quantities. The female body makes three types of estrogen called estrone, estradiol and estriol. The level of each ... Read more

Excitatory neurotransmitters

Excitatory neurotransmitters are the chemical messengers released by neurons which promote activation in the receiving neuron. They have a stimulating effect on the brain. These include dopamine (which can also act as an inhibitory neurotransmitter), ... Read more

Frontal lobe

One of the four major lobes, or regions, of the cerebral cortex. The frontal lobe plays a key role in higher-cognitive functions including motor functions, sensory functions, perception, attention, awareness, language, memory, cognition and personality.Queensland ... Read more


Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in our central nervous system. Glutamate and glutamine are precursors of GABA, which can be thought of as the yin to glutamate’s yang: while glutamate fires neurons up, GABA slows ... Read more


Glutamate is a primary excitatory neurotransmitter in the brain which acts to fire neurons up and is the yin to GABA’s yang. It plays an important role in attention, learning, memory and neuroplasticity. Overactivity in glutamate receptors is linked ... Read more


The hippocampus is part of the limbic system and is often called the ‘memory centre’ of the brain. It is responsible for the formation of episodic memories (memories of experiences) and creates associations between our memories and our senses. The ... Read more


Homeostasis is a state of relative stability and regulation of the internal condition of cells and organisms. These internal conditions include temperature, water, and sugar levels. Homeostasis allows the cell or organism to function at an optimal level, ... Read more


Hormones are chemical messengers in the body which are produced and secreted by glands in the endocrine system. They play a crucial role in most bodily functions, from simple basic needs like hunger to complex systems like reproduction, and also our emotions ... Read more

HPA axis

The hypothalamic-pituitary-adrenal (HPA) axis refers to one of our most crucial stress response systems. When faced with a stressful situation the hypothalamus releases corticotropin-releasing hormone (CRH) which triggers the pituitary gland to release ... Read more


The Hypothalamus, is part of the limbic system. It is an almond sized part of the brain which links the endocrine system to the nervous system via the pituitary gland. It produces stimulating and inhibiting hormones which start and stop the production ... Read more

Inhibitory neurotransmitters

Inhibitory neurotransmitters are the chemical messengers released by neurons which inhibit activation in the receiving neuron. They have a calming effect on the brain. These include serotonin, GABA and dopamine (which can also act as an excitatory neurotransmitter).Queensland ... Read more

Limbic system

The amygdala, hippocampus and hypothalamus are the three major structures which form the limbic system. The limbic system is a term that refers to this group of structures in the brain which are collectively involved in behavioural and emotional responses, ... Read more


The neocortex is a sheet of tissue that forms the outermost layer of the brain and the largest part of the cerebral cortex. It is sometimes called the “primate brain” as it is the area of the brain that has developed considerably in non-human primates ... Read more

Nervous system

The nervous system refers to the complex network of nerve cells throughout the body which control sensory input and motor output by communicating with the brain and spinal cord (central nervous system). This process is crucial in maintaining homeostasis.Mandal, ... Read more

Neuroendocrine system

The neuroendocrine system facilitates communication between the central nervous system and the endocrine system. It is composed of neurons, glands and tissue throughout the body that produce chemicals, hormones and signals which are crucial in maintaining ... Read more


Neuromodulators are chemicals which do not directly activate neurons in the body but act together with neurotransmitters to enhance the excitatory or inhibitory responses of the neurons in order to regulate functions in the body. It is often difficult ... Read more


Neurons, also called nerve cells, are the cells responsible for receiving sensory information from the external world, sending motor commands to our muscles, and transforming and relaying electrical signals at every stage in between. We each have roughly ... Read more


Neuroplasticity refers to the brain's ability to form new neural connections throughout life as a way of adapting to new situations or changes in the environment. This is especially important in the case of injury or disease.MedicineNet. (2017). Definition ... Read more


Neurotransmitters are chemical messengers released by neurons throughout the nervous system, transmitting an impulse from one cell to the next. Neurotransmitters are made in the brain, but also by the bacteria in our gut. Neurotransmitters are either ... Read more


Noradrenaline, also known as norepinephrine, is a chemical that functions primarily as an excitatory neurotransmitter, but also as a hormone. It is made from the amino acids phenylalanine and tyrosine, and is stored and released from neurons throughout ... Read more

Occipital lobe

The occipital lobe is one of the four major lobes, or regions, of the cerebral cortex. It is the visual processing centre of the brain and responsible for interpreting depth, distance, location and the identity of objects in our visual field.Queensland ... Read more


Oxytocin is a hormone produced by the hypothalamus and secreted by the pituitary gland. It is often referred to as the ‘love hormone’ as it plays a key role in social interaction and bonding behaviour. Oxytocin is released during orgasm, childbirth, ... Read more

Parathyroid glands

The parathyroid glands are four pea-sized glands found behind the thyroid gland in the neck. They are responsible for producing parathyroid hormone, which controls calcium levels in the blood. When low calcium levels are detected, the parathyroid gland ... Read more

Parietal lobe

The parietal lobe is one of the four major lobes, or regions, of the cerebral cortex. The parietal lobe plays a key role in sensory processes, attention and language. Sensory information including touch, temperature, pressure and pain is integrated here.Queensland ... Read more

Pituitary gland

The pituitary gland is about the size of a pea that sits in the sphenoid bone which is just behind the bridge of our nose. It is attached to the base of our brain by a thin stalk. The pituitary gland is controlled by the hypothalamus and is often called ... Read more

Posterior cingulate gyrus

The posterior cingulate gyrus (PCG) is situated in the parietal lobe of the brain and is involved in cognition. There is no consensus as to its specific function but it is thought to play a role in focus of attention, memory and planning.Leech, R., & ... Read more

Prefrontal cortex

The prefrontal cortex, sometimes referred to as the “executive centre” of the brain, is located at the very front of the frontal lobe and accounts for around 30% of the human brain. It is involved in higher cognitive functions such as problem solving, ... Read more


Progesterone is a hormone released by the corpus luteum - a temporary gland that the female body produces each cycle after ovulation. It plays an important role in the menstrual cycle and is crucial in maintaining the early stages of pregnancy. Progesterone ... Read more

Reptilian brain

The reptilian brain (called such because it is made up of the main structures in a reptile’s brain: the brainstem and cerebellum) is the most primitive part of our brain and, in evolutionary terms, it is the oldest part of our brain. It is responsible ... Read more


Serotonin (scientifically known as 5-HT ) is an inhibitory neurotransmitter found in the brain but also in large quantities in the gut (about 95% of the body’s serotonin is in the digestive tract). An amino acid called tryptophan is a precursor to serotonin. ... Read more

Sympathetic nervous system

The sympathetic nervous system (SNS) is a branch of the nervous system which acts to prepare the body for fight or flight in times of stress by controlling the function of organs throughout the body. SNS activation is therefore often referred to as the ... Read more

Temporal lobe

The temporal lobe is one of the four major lobes, or regions, of the cerebral cortex. It is responsible for sensory information processing such as hearing, recognising language, making sense of visual information and forming sensory memories.Queensland ... Read more


Testosterone is a male sex hormone (also found in smaller quantities in females) produced mainly in the testes, but also the adrenal glands and ovaries. It is responsible for many physical characteristics specific to adult males including facial hair, ... Read more

Thyroid gland

The thyroid gland is an endocrine gland situated in our neck just below the Adam’s apple. It makes two hormones that are secreted into the blood: thyroxine (T4) and triiodothyronine (T3). The release of these hormones influences the metabolism of the ... Read more