Cortisol and Stress Flashcards
What is cortisol?
A lipid soluble hormone which is produced as it is required
How does cortisol travel?
Carried in the blood bound to a carrier protein
Where does cortisol travel?
To the target cell and passes through the cell membrane
What does cortisol do once it has passed through the cell membrane?
Binds to a specific receptor which is usually found in the cytoplasm
What does cortisol don once bound to the specific receptor?
The receptor hormone complex moves into the nucleus
What does cortisol do once in the nucleus?
Activates specific genes
What does cortisol do once it has activated specific genes?
Produces mRNA and then a protein
What happens once the protein has been produced?
The protein has an effect
What is the stimulus for cortisol?
Stress and non-stress neural inputs (day-night rhythm, low blood glucose concentration)
What does stress and non-stress neural inputs cause?
The hypothalamus to secrete corticotropin releasing hormone (CRH)
What does corticotropin releasing hormone do?
Causes the anterior pituitary to secrete adrenocorticotropic hormone (ACTH)
What does adrenocorticotropic hormone do?
Causes the adrenal cortex to secrete cortisol
What effects does cortisol have?
Metabolic effects and other effects
What cells does cortisol effect metabolically?
Muscle, fat and liver
What does cortisol do to muscle cells?
Increase protein breakdown and decrease glucose uptake
What does cortisol do to fat cells?
Increase fat breakdown and decrease glucose uptake
What does cortisol do to liver cells?
Increase glucose synthesis (gluconeogenesis from the fat and protein which have been broken down by the muscle and fat cells)
What are the other effects of cortisol?
Helps one to cope with stress, long term it suppresses the immune system and is essential for maintaining normal blood pressure
What is cortisol secretion controlled by?
Negative feedback during the non-stress stimulus. Negative feedback does not occur when the stimulus is stress
What happens in the negative feedback of cortisol?
Cortisol goes and acts on the hypothalamus and anterior pituitary to prevent release of corticotropin releasing hormone and adrenocorticotropic hormone
What is the daily pattern of cortisol?
Pulses during the day in response to specific conditions in the body which the highest peak upon waking
What effects the pattern of cortisol?
Any disturbance of normal sleep patterns
What effects does cortisol have?
Increasing blood glucose levels, increasing fat, protein and carbohydrate metabolism to maintain blood glucose, promoting anti-inflammatory actions, increasing blood pressure, increasing heart and blood vessel tone (force) and contraction and activation of the central nervous system (CNS)
What is hypo secretion?
Too little (or no) secretion of a hormone
What is hyper secretion?
Too much secretion of a hormone
What is hyposensitive?
When hormone receptors aren’t very sensitive and cause little (or no ) response
What is hypersensitive?
When hormone receptors are too sensitive and cause too much response
What can cause problems with hormone signalling?
Autoimmunity, genetic mutation, tumors and many other factors
What does autoimmunity do to effect hormone signalling?
Destruction of hormone receptors
What does genetic mutation do to effect hormone signalling?
They can cause gain or loss of function
What do tumors do to effect hormone signalling?
Excess tissue usually leads to excess hormone release but can sometimes prevent release
What is Addison’s disease?
Hyposecretion of cortisol caused by autoimmunity (destruction of adrenal cortex receptors) or other factors
What happens as a result of destruction of adrenal cortex receptors in Addison’s disease?
Lowered secretion of cortisol and aldosterone
What does low cortisol secretion in Addisons disease lead to?
Increased ACTH (adrenocorticotropic hormone) secretion
What does excess ACTH cause?
Melanin synthesis which results in changing skin colour
What are other symptoms of addisons disease?
Low blood pressure and weakness (lack of fuel)
What is Cushing’s disease?
Hypersecretion of cortisol caused by tumors which lead to excess release or other factors
What are symptoms of Cushing’s disease?
High blood pressure and weakness (muscle wasting)
What is the beginning of the stress response?
The stress stimulus (physical, mental or other) activates the hypothalamus
What happens once the hypothalamus is activated?
The hypothalamus organises a response and activates the adrenal glands, sympathetic nervous system and posterior lobe of pituitary gland
What happens once the hypothalamus organises a response?
The body responds
What happens when a stress stimulus is received (integrated stress response)?
The hypothalamus secretes corticotropin releasing hormone, action potentials travel down sympathetic preganglionic fibres and synapse in the adrenal medulla and action potentials travel down neuronal connection to the posterior pituitary
What happens as a result of corticotropin releasing hormone being secreted by the hypothalamus in the integrated stress response?
It causes the anterior pituitary to secrete adrenocorticotropic hormone
What happens as a result of adrenocorticotropic hormone being secreted by the anterior pituitary in the integrated stress response?
The adrenal cortex synthesises and secretes cortisol
What happens as a result of cortisol being secreted by the adrenal cortex in the integrated stress response?
Increased blood glucose (gluconeogenesis in the liver) and increased blood pressure
What happens as a result of action potentials travelling down sympathetic preganglionic fibres and synapsing in the adrenal medulla in the integrated stress response?
The adrenal medulla secretes adrenaline
What happens as a result of the adrenal medulla secreting adrenaline in the integrated stress response?
Increased blood glucose (glycogenolysis in liver and skekletal muscle), increased heart rate (effects heart pacemaker cells and muscle) and increase blood presure
What happens as a result of action potentials travelling down the neuronal connections to the posterior pituitary in the integrated stress response?
The posterior pituitary secretes antidiuretic hormone
What happens as a result of the posterior pituitary secreting antidiuretic hormone in the integrated stress response?
Decreased water excretion (in kidneys), increased blood volume and increased blood pressure
What are the phases of the stress response?
Alarm phase, resistance phase and exhaustion phase
What happens in the alarm phase?
The same as the responses in the sympathetic nervous system (short term) which are increased heart rate, decreased gastric motility, increased pupil size, decreased salivation, increased flow of blood to muscles by constricting blood vessels and increased sweating
What happens in the resistance phase?
Cardiovascular diseased hypertension which are linked to accumulated stress
What happens in the exhaustion phase?
Heart attack
What can prolonged stress do?
Have a negative effect on health
