Biopsychology Flashcards
Action Potential
when a neurone is activated by a stimulus, the inside of the cell becomes positive charged for a short time, known as action potential
Adoption Studies
involve comparing a trait or characteristic between adopted children and their biological or adoptive parents
Adrenal Cortex
the outer portion of the adrenal gland that produces steroid hormones, which regulate carbohydrate and fat metabolism, and mineralocorticoid hormones, which regulate salt and water balance in the body
Adrenal Gland
triangle-shaped glands that sit on top of the kidneys and regulate stress response through the synthesis of hormones, including adrenaline and cortisol
Adrenal Medulla
releases adrenaline and noradrenaline, they key hormone in the fight or flight response
Adrenaline
a hormone that triggers the body’s fight-or-flight response and is produced by the adrenal medulla in the adrenal glands as well as some of the central nervous system’s neurones
ACTH
Adrenocorticotropin
a hormone produced by the anterior pituitary gland that stimulates the adrenal cortex
Agenesis of the Corpus Callosum
absence of the corpus callosum
Alpha Waves
rhythmical, relaxed alpha waves occur when a person is awake and decrease as a person moves from light to deep sleep
Amygdala
part of the limbic system which is regarded as the older region of the brain in the evolutionary sense, therefore many of the structures within the limbic system are seen to have some sort of survival benefit; the amygdala in particular has been identified as a structure with links to emotional regulation and aggression
Antagonistic
where systems work usefully in opposition to each other, and therefore cannot work at the same time, such as the sympathetic and parasympathetic nervous system
Auditory Cortex
part of the temporal lobe that processes auditory information
Autonomic Nervous System
transmits and receives messages to the organs and it is divided further into the sympathetic and parasympathetic nervous system
Axon
an extension of the neuron that carries the impulse away from the cell body and is carried in a myelin sheath
Axonal Sprouting
growth of new nerve endings that connect with other undamaged nerve cells to form new neural pathways
Basal Ganglia
area at the base of the forebrain, coordinates movement and learning
Caudate Nucleus
involved in associative learning and inhibition
Putamen
involved in motor skill learning
Striatum
involved in motivation
Substantia Nigra
involved in reward and addiction
Beta Waves
found during REM
Biochemistry
the branch of science concerned with the chemical and physio-chemical processes and substances that occur within living organisms
BRAC
Basic Rest Activity Cycle
alertness, then fatigue in a ninety minute rhythm that repeats in the sleep cycle
Brain
maintains life and involves higher functions and psychological processes
Brain Stem
regulates our most primitive and involuntary behaviours such as breathing, sleeping or sneezing, also known as the central core
Broca’s Aphasia
characterised by partial loss of speech ability, but does not affect comprehension, caused by issues with Broca’s area
Broca’s Area
region of the brain that contains neurons involved in speech function
Campbell and Murphy
they shone light onto the back of knees of fifteen participants when they woke them at various points in the night and managed to vary their sleep cycle by up to three hours
Cell Body
contains the nucleus which contains the chromosomes
Central Nervous System
consists of the brain and spinal cord, relaying messages to and from an individual’s environment in order to maintain life
Central Core
regulates our most primitive and involuntary behaviours, such as breathing, sleeping or sneezing, also known as the brain stem and includes structures such as the hypothalamus, regulating eating, drinking, the endocrine system and homeostasis
Cerebellum
the largest part of the brain, divided into four lobes
Cerebral Cortex
the outermost layer of the cerebrum and each of our sensory systems send messages to and from the cerebral cortex
Cerebrum
regulates our higher intellectual processes
Chromosomes
a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes
CIMT
Constraint Induced Movement Therapy
a form of physiotherapy which aims to encourage patients to use their weaker limb more whilst restraining the good arm by carrying out intense repetitive tasks, works on the premise of neural plasticity
Cingulate Gyrus
forms a major part of the limbic system
Circadian Rhythm
a type of biological rhythm that operates along a 24-hour cycle, regulating a number of bodily processes such as core body temperature
Commissurotomy
this is where the corpus callosum is severed so the two hemispheres are separated and don’t communicate with each other and was done to control frequent and severe epileptic fits
Concordance Rates
refers to the extent to which a pair of twins share similar traits or characteristics
Corpus Callosotomy
a procedure involved in treating epilepsy that involves severing the corpus callosum to stop seizures bouncing between the two hemispheres
Corpus Callosum
a bundle of approximately 200 million nerves that pass between the two hemispheres, enables messages to enter the right hemisphere and be conveyed to the left hemisphere and vice versa
Cortical Reorganisation
the process by which an existing cortical map is affected by a stimulus resulting in the creation of a new cortical map
CRH
Corticotropin-Releasing Hormone
this is produced by the hypothalamus and triggers ACTH to be produced by the pituitary gland
Cortisol
a hormone produced by the adrenal gland that is involved in the chronic stress response and increases blood pressure and blood sugar levels
Delta Waves
occur during deep sleep
Dement and Kleitman (1957)
monitored brainwave activity of nine participants using an EEG and found that REM activity highly correlated with dreaming and replications have found similar findings
Dendrites
extend from the cell body and carry electrical impulses from other neurones towards the cell body
Diurnal
the opposite of nocturnal
Dizygotic
twins formed from two separate eggs that both become fertilised with different sperm, hare 50% of their DNA, the same as normal siblings or parents
Dormant Plasticity
synapses which have not received enough input to be active
Dragonski et al (2006)
medical students had brain images taken three months before and after their final exams. Learning-induced changes were seen to have occurred in the posterior hippocampus and the parietal cortex, presumably as a result of studying for exams
EEG
Electroencephalogram
measures activity in the brain using electrodes placed on the scalp that detect small electrical charges resulting from brain cell activity, and when electrical signals form the different electrodes are graphed over a period of time, the resulting impression is the EEG, which can be used to diagnose brain injury, disease and disorder such as epilepsy and Alzheimer’s
Effectors
muscles or glands
Endocrine System
maintains levels of hormones, controlling vital functioning but works slower than the nervous system because hormones travel through the blood but is more effective than the nervous system with more powerful widespread effects, this is all done via glands in the body that use hormones as chemical messages in the bloodstreams
Endogenous Pacemakers
internal body clocks that regulate biological rhythms
Entrainment
the process by which the biological clock is reset each day by cues in the environment
Epigenetics
the theory that you can inherit genes that make it likely you will have certain mental abnormalities, but an environmental trigger is also needed
Ericsson (1993)
found that the best violinist tended to practise for three sessions throughout the course of the day, each for no longer than ninety minutes with a break in between to recharge
ERPS
Event Related Potentials
types of brainwaves triggered by particular events, can be studied when neural responses isolated with specific sensory, cognitive or motor events are isolated using a statistical averaging technique where all extraneous brain activity from an EEG is filtered out
Evolution
a biological force that shapes behaviour through adaptation via natural selection
Exogenous Zeitgeber
external cues that influence our biological rhythms
Family Studies
where psychologists study families in order to investigate the genetic basis of behaviour
Fight or Flight Response
the way all animals, including humans, respond to stress as it becomes physiologically aroused to fight an aggressor or run away
fMRI Scans
Functional Magnetic Resonance Imaging Scans
scans that produce images related to the levels of oxygen in the blood and therefore to metabolic function, and hence, localised brain activity. These scanners produce images related to the water molecule’s hydrogen nuclei and therefore to anatomical structure. These are expensive and are mainly used for experimental research
Frontal Lobe
each of the paired lobes of the brain lying immediately behind the forehead, including areas concerned with behaviour, learning, personality, and voluntary movement
Functional Recovery
the transfer of functions from a damaged area of the brain after trauma to other undamaged areas
Francis Galton (1869)
stated that all abilities are inherited, a very simplistic viewpoint, but later had to agree that any resemblance between family relatives could be a result of both genes and the shared environment
FSH
Follicle-Stimulating Hormone
hormone that causes an egg to mature and stimulates ovaries to produce oestrogen
Ganglion
mass of grey matter within the central nervous system
Gazzaniga (1998)
suggests that some of the early discoveries from split-brain research have been disconfirmed by recent studies, because case studies have demonstrated that people can develop the capacity to speak out of the right hemisphere
Genes
basic units of hereditary, function in pairs and the recombination of genes from parents to offspring provides the basis for genetic variability. Genes only determine the potential for characteristics and the observable characteristics of an individual depend on the interaction of genetic and environmental factors
Genetic Material
made up of DNA, which, for sexually reproducible organism, are given by the sperm and egg of the parents
Genotype
the genetic make up of an individual
Ghrelin
the hormone that is produced when someone is hungry
Glands
produce and secrete hormones that the body uses for a wide range of functions; these control many different bodily functions including respiration, metabolism, reproduction, sensory perception, movement, sexual development and growth
Glucose
the product of digesting starch, a sugar found in the body
Glycogen
glucose that is stored in the liver and muscles when carbohydrates are consumed
Grey Matter
the cell bodies in the cerebral cortex, which causes the cerebral cortex to look grey
Growth Hormone
a substance that controls growth, including muscle mass and decreasing body fat
Gross and Rolls (2008)
found that the SCN probably coordinates the behaviour of other body cells by sending neural signals or releasing neurohormones
Hemispherectomy
where one hemisphere is completely removed
Hemispherical Specialisation
where on hemisphere dominates for a specific task
Hippocampal Volume
how large someone’s hippocampus is
Homeostasis
the body’s natural ability to maintain a stable and balanced internal environment despite external circumstances
Hormones
made by the endocrine glands, these are chemical messengers that travel in the bloodstream to tissues or organs, and affect many processes, including growth, metabolism, sexual function, reproduction and mood
Hubel and Wiesel (1963)
involved sewing one eye of a kitten shut and analysing the brain’s cortical responses. It was found that the area of the visual cortex associated with the shut eye was not idle as had bee predicted but continued to process information from the open eye
Hypothalamus
coordinates both the autonomic nervous system and the activity of the pituitary, controlling body temperature, thirst, hunger, and other homeostatic systems, and involved in sleep and emotional activity
Lateral Hypothalamus
regulates food intake and sleep
Ventromedial Hypothalamus
the centre of the hypothalamus, involved in terminating hunger, fear, thermoregulation, and sexual activity
Inferior Colliculi
a structure in the midbrain that serves as a relay point for auditory information
Infaradian Rhythm
biological rhythms that occur less than once every twenty four hours, such as the menstrual cycle
Insulin
allows cells to absorb glucose in the blood, controls storage of glycogen in the liver
Jody Miller
had a hemispherectomy as a toddler for Rasmussen’s Encephalitis, which caused some mild paralysis but Jody is otherwise healthy and is living a normal life because the left hemisphere was able to take over the role of the right hemisphere
Karl Lashley (1950)
suggests that the basic motor and sensory functions are localised, but higher mental functions are not. Lashley claimed that intact areas of the cortex could take over specific cognitive functions following injury to the areas normally responsible for that function and the effects of brain damage are determined by extent rather than location
Kleitman (1969)
suggested that there is a ninety minute cycle during waking hours as well as during sleep
Lateralisation
the dominance of one hemisphere of the brain for particular physical and psychological functions
Lateral Ventricles
the two largest ventricles in the brain, containing cerebrospinal fluid
Leucotomy
cutting connections to a particular part of the brain
LH
Luteinizing Hormone
hormone that causes mature eggs to be released from the ovary
Limbic System
this is around the central core of the brain and is interconnected with the hypothalamus which contains the hippocampus, controls emotions and plays a key role in memory
Longitudinal Fissure
groove between the two hemispheres
Long-Term Potentiation
a process by which synaptic connections between neurons become stronger with frequent activation
Master Gland
the pituitary gland, secretes many of the most important hormones in the body
Maze Bright Rats
rats who found their way through the maze with few problems
Maze Dull Rats
rats who found their way through the maze with immense difficulty, or didn’t find their way through at all
Mechelli et al (2004)
it was found that bilingual people have a larger parietal cortex than monolingual controls
Medina et al (2007)
found that prolonged use of marijuana resulted in poorer cognitive functioning as well as an increased risk of dementia in later life
Medulla
the bottom most part of the brain, where the spinal cord attaches to the brain
Melatonin
responsible for biological rhythms, including the sleep-wake cycle
Menaker et al (1978)
bred hamsters with circadian rhythms of 20 hours rather than 24; neurones from the abnormal hamsters were then put into the brains of normal hamsters, who then also developed rhythms of 20 hours, showing the importance of the SCN
Michael Siffre
in 1962, Siffre spent two months in a dark cave, showing that the circadian cycle was slightly over 24 hours long. In 1972, Siffre spent six months in a dark cave, and this affected his dexterity, eyesight and memory. In 1999, he spent seventy-six days underground
Midbrain
a small central part of the brainstem
Miles et al (1997)
a case study of a young man who was blind from birth and had a circadian rhythm of 24.9 hours. Despite exposure to social cues, his sleep wake system could not be adjusted and consequently, he had to take sedatives at night and stimulants in the morning to keep pace with the 24-hour world
Mineralocorticoid Hormones
regulate salt and water balance in the body, produced by the adrenal cortex
Monozygotic
twins formed from a fertilised cell that split in two to form two separate embryos, share 100% of the same DNA
Mora Leeb
had a stroke in utero that destroyed the left half of her brain, did not walk until the age of two, talk in full sentences until six and has some vision impairments and some level of learning disability but would not be doing as well without functional recovery
Myelin Sheath
a fatty substance that covers the axon, the main purpose of which is to increase the spread at which impulses propagate
Neural Plasticity
describes the brain’s tendency to change and adapt functionally and physically as a result of experience and new learning
Neurochemical Underpinnings
something that can be explained by neurotransmitters
Neurochemistry
the branch of biochemistry concerned with the processes occurring in nerve tissue and the nervous system
Neurohormones
a hormone produced by nerve cells and secreted into the bloodstream
Neuronal Unmasking
the process by which functional recovery happens, where dormant synapses open connections to compensate for a damaged area of the brain
Neurones
nerve cells that relay information to the central nervous system
Motor Neurones
carry signals from the CNS to effectors, have short dendrites and long axons, connect the CNS to effectors and are found in the CNS and control muscle movements. When motor neurones are stimulated, they release neurotransmitters that bind to receptors on muscles to trigger a response which lead to movement
Relay Neurones
carry messages from one part of the CNS to another, have long dendrites and short axons, are found in the spinal cord and allow sensory and motor neurones to communicate
Sensory Neurones
carry signals from receptors to the spinal cord and the brain, have long dendrites and short axons and are found in receptors such as the eyes, ears, tongue and skin. When the impulses reach the brain, they are translated into sensations such as vision, hearing, taste and touch. However, not all sensory neurones reach the brain, as some stop at the spinal cord, allowing for reflex actions
Neurophysiological Underpinnings
something that can be explained by physical structures in the brain
Neurorehabilitation
rehabilitating people after brain damage
Neurosurgical Evidence
this is by far the most extreme treatment as it involves the destruction of healthy brain tissues. It is still used for treatment-resistant severe depressives and extreme cases of OCD. The success of these procedures strongly suggests that symptoms and behaviours associated with severe mental disorders are localised
Neurotransmitters
chemicals transmitted within the brain via cerebral fluid that diffuse across the synaptic cleft
Nodes of Ravier
breaks in the myelin sheath of between 0.2 to 2mm
Noradrenaline
hormone produced by the adrenal glands, also acts as a neurotransmitter, a chemical messenger that transmit signals across nerve endings in the body and together with hormones, helps the body respond to stress and exercise
NREM
Non Rapid Eye Movement
the deep stage of sleep when memories are consolidated
Nucleus
the part of the cell body that contains the chromosomes
Nucleus Accumbens
works in the reward circuit of brain producing dopamine
Occipital Lobe
the rearmost lobe in the cerebral hemisphere of the brain
Oestrogen
hormone that stops the production of FSH, causes the pituitary gland to secrete LH
Optic Chiasm
the part of the brain where optic nerves cross
Optic Nerves
transmit impulses from the retina to the brain
Ovaries
the egg producing organisms found in females that produces oestrogen and progesterone
Oxytocin
a hormone released by the pituitary gland that causes increased contraction of the uterus during labour and stimulates the ejection of milk into the ducts of the breasts
Pancreas
secretes insulin which helps glucose move from the blood into the cells to be used for energy, and secretes glucagon when blood sugar is low
Parahippocampal Gyrus
grey matter cortical region of the brain that surrounds the hippocampus and is part of the limbic system
Parasympathetic Nervous System
maintains or decreases bodily activities when relaxed
Parietal Lobe
the lobe at the top of the head, concerned with reception and correlation of sensory information
Patient EB
had a hemispherectomy at two and a half to remove a brain tumour and suffered immediate loss of language abilities. By age five, had no language problems, performed visual-spatial and face recognition tasks normally and had an IQ of 78. By age 17, he performed normally apart from some minor grammatical problems and syndromic dyslexia
Patient JW
an epileptic patient who, prior to having a corpus callosotomy, had a language-dominant left hemisphere, but later recovered, showing how the brain can recover functions
Patient Tan
a patient who displayed speech problems in life and post mortem was found to have a lesion on his Broca’s area
Peripheral Nervous System
extends beyond the central nervous system to transmit messages from the brain to the whole body and vice versa
Peterson (1988)
used brain scans to demonstrate how Wernicke’s area was active during listening tasks and Broca’s area was active during reading tasks, suggesting these areas are responsible for these tasks
Phantom Limb Syndrome
60-80% of amputees experience this due to cortical reorganisation in the somatosensory cortex that occurs as a result of limb loss
Phenotype
the characteristics shown by an individual that occur due to their genes and environment
Pheronomes
a chemical substance produced and released into the environment by an animal affecting the behaviour or physiology of others of its species
Phineas Gage
a man working on the railway who was involved in an accident where a metal pole went through his brain and survived, though had a vastly different personality afterwards
Pineal Gland
a small endocrine gland located in the centre of the brain between the two hemispheres, secretes melatonin which helps regulate sleep/wake patterns
Pituitary Gland
a small endocrine gland located at the base of the skull, also known as the master gland, secretes most of the important hormones in the body, including those that control growth, blood pressure, breast milk production, metabolism, reproduction and stress
Pons
part of the brainstem that links the brain to the spinal cord
Postmortem Examination
used to establish underlying neurobiology of a particular behaviour
Prefrontal Cortex
part of the brain that regulates emotional behaviour, has reduced activity in psychopaths
Progesterone
maintains the lining of the uterus wall
Propagate
the way impulses are transmitted along myelin sheaths
Ralph et al (1990)
removed the SCN from hamsters brains and was able to breed mutant hamsters with a 20-hour rhythm rather than 24
Randy Gardener
Randy was a DJ who remained awake for 11 days and 24 minutes for a radio show. He experienced blurred vision, disorganised speech, memory problems, mood swings and then began experiencing symptoms similar to schizophrenia
Rasmussen’s Encephalitis
a rare neurological disease causing chronic inflammation on one side of the brain leading to drug-resistant epilepsy, hemiplegia and progressive loss of motor and cognitive skills, for which the only treatment is surgery, generally hemispherectomy
Recruitment of Homologous Areas
similar areas on the opposite side of the brain take over tasks that the damaged area would have performed
Reformation of Blood Vessels
blood vessels regrow to ensure oxygen and glucose can serve the brain
Retinohypothalamaic Tract
a photic neural input pathway involved in the circadian rhythms of mammals
Rusak and Zucker (1975)
found that SCN-lesioned hamsters began to secrete testosterone all year round instead of just in breeding season
Schneider et al (2014)
patients with the equivalent of a university degree are seven times more likely to be disability-free after moderate to severe traumatic brain injury
SCN
Suprachiasmatic Nucleus
lies in the hypothalamus
Selective Breeding
method involves artificially selecting male and female animals for a particular trait. These animals are then put together in order to breed and produce offspring. Selective breeding has been used to demonstrate how a number of behavioural characteristics may have a genetic basis
Sleep Cycle
an example of a circadian rhythm
Stage 1
makes up 4-5% of sleep, light sleep where muscle activity slows down and there is occasional muscle twitching
Stage 2
makes up 45-55% of sleep, breathing pattern and heart rate slows and there is slight decrease in body temperature
Stage 3
makes up 4-6% of sleep, where deep sleep begins to generate slow delta waves
Stage 4
makes up 12-15% of sleep, very deep sleep, where there is rhythmic breathing, limited muscle activity and the brain produces delta waves
Stage 5
makes up 20-25% of sleep, rapid eye movement occurs, brain waves speed up and dreaming occurs, muscles relax and heart rate increases, breathing is rapid and shallow
Somatic Nervous System
transmits and receives messages from senses but also directs muscles to react and move
Sperry (1968)
a study on split brain patients that showed which hemisphere is responsible for multiple tasks
Spinal Cord
receives and transmits information to and from the system
Split-Brain Operation
an operation that involves severing the corpus callosum, often done in patients with severe epilepsy, the idea being that by cutting the connection, the electrical signals would not be able to bounce between the two hemispheres reducing the number of seizures a person would have. This includes using mental images, forming concepts and developing schemas
Stephan and Zucker (1972)
found that cycles of sleep, feeding and activity are disrupted if the SCN is removed or damaged as light is no longer able to rest the clock each day
Steroid Horones
regulates carbohydrates and fat metabolism, regulated by adrenal cortex
Spontaneous Recovery
whereby functional recovery originally happens fast and then slows down over several weeks or months, at which point rehabilitative therapy may be needed
Superior Colliculi
directs eye movement and handles visual input from the retina
Sweaty Lip Ladies Study
McClintock gathered 29 women with irregular periods and wiped pads containing the sweat of nine women with regular periods on their upper lips, as sweat contains pheronomes. 68% of women experienced changes to their cycle which brought them in line with the cycle of their donor
Sympathetic Nervous System
activates bodily activities when stressed
Synapse
a very small gap between neurones
Synaptic Cleft
the gap between two neurones
Synaptic Pruning
rarely used neuronal connections are deleted and frequently used ones are strengthened
Synaptic Transmission
how chemical diffuse across the synapse and bind with receptor molecules on the membrane on the next neurone, stimulating the second neurone to transmit the electrical impulse
Szaflarski et al (2006)
found that language became more lateralised to the left hemisphere with increasing age in children and adolescents, but after the age of 25, lateralisation then decreased with each decade of life, suggesting that lateralisation changes with normal ageing
Tajiri et al (2013)
provides evidence for the role of stem cells in recovery from brain injury. Purposefully brain injured rats were assigned two groups, one of which received stem cell injections into the damaged region of the brain. Three months later, those who had received stem cells showed clearer development of neurone-like cells the areas of the injury accompanied by a solid stream of stem cells migrating to the brain’s site of injury, which was not the case with the control group
Taylor (2000)
found gender differences in the fight or flight response
Testosterone
a steroid androgen hormone and the primary male sex hormone, produced by the testes in men and ovaries in women, and it plays key roles in libido, energy and immune function in both men and women
Theta Waves
occur during light sleep
Temporal Lobe
the lobe underneath the temples, concerned with understanding speech
Testes
the male reproductive organs that produce sperm and testosterone
Thalamus
either of two masses of grey matter lying between the cerebral hemispheres on either side of the third ventricle, relaying sensory information and acting as a centre for pain perception and maintaining and updating internal value representations
Tryon’s Rat Experiment
Robert Tryon had a group of rates solve a maze, then bred maze bright rats with maze dull rats, and had the maze bright rats raise maze dull rats, and vice versa. Despite this, the bright rats still did better in the maze than the dull rats
Twin Studies
where psychologists study twins in order to investigate the genetic basis of behaviour
Tyrosine
used to make dopamine
Ultradian Rhythm
biological rhythms that occur more than once in 24 hours
Wernicke’s Aphasia
characterised by difficulty comprehending spoke and written language despite being able to speak fluently, caused by issues with Wernicke’s area
Wernicke’s Area
a region of the brain concerned with the comprehension of language
Zygote
a fertilised egg
Gut
Sympathetic Nervous System: slows digestion
Parasympathetic Nervous System: increases digestion
Salivary Glands
Sympathetic Nervous System: inhibits saliva production
Parasympathetic Nervous System: increases saliva production
Heart
Sympathetic Nervous System: increases heart rate
Parasympathetic Nervous System: decreases heart rate
Liver
Sympathetic Nervous System: stimulates glucose production
Parasympathetic Nervous System: stimulates bile production
Bladder
Sympathetic Nervous System: stimulates urination
Parasympathetic Nervous System: inhibits urination
Eyes
Sympathetic Nervous System: dilates pupils
Parasympathetic Nervous System: constricts pupils
Lungs
Sympathetic Nervous System: dilates bronchi
Parasympathetic Nervous System: constricts bronchi
Thyroid Disorders
typically result when the gland releases too little or too much thyroid hormone
Thyroid Gland
gland located in the neck, regulates metabolism, which is the body’s ability to break down food and convert it to energy
T4
Thyroxine
plays a crucial role in heart and digestive function, metabolism, brain development, bone health and muscle control, secreted directly into the blood stream by the thyroid gland
Yamazaki et al (2000)
reported that circadian rhythms persist in culture-grown tissues in the laboratory implying that body cells seem to follow the circadian activity even when they are not under the direct control of the SCN
