The Endocrine System Flashcards
What hormones are lipophilic and can cross membranes?
Steroid hormones
(Vice versa)
Non-steroid, non lipophilic
Give an example of a short chain non-steroid hormone
Antidiuretic hormone
Give an example of a long chain non-steroid hormone
Human growth hormone, insulin, glucagon.
Where in the cell are pre-pro-hormones activated? How does activation occur.
The golgi apparatus.
Pre-pro-hormones are broken down and folded into an active quaternary structure.
How do second messengers work?
Penetrate the cell, enter the nucleus and induce translation and transcription.
What is up regulation?
Down regulation
Increases sensitivity, when there are more membrane receptors present.
(Vice versa for down regulation.)
What is hyperfunction?
Excess production and secretion of a hormone. Caused by upregulation.
What is hypofunction?
Decreased production and secretion. Caused by down regulation or lack of receptor function.
What are the functions of the hypothalamus?
Thermoregulation, hormone secretion, circadian rhythms (day/night cycles over 24 hour period) motivation (thirst, sexual behaviour) and emotions.
Name the two types of hormone secretions.
Primary: Acts directly.
Trophic: Cascade event that then produces the hormone..
Describe the process of thermoregulation.
Core body temperature changes, thermoreceptors detect the change, compared to a set point where it establishes if the body is too hot/cold, effectors then either increase heat production or decrease heat production.
What is adenohypophysis?
The interaction between the hypothalamus and the anterior pituitary gland.
Hormones from the hypothalamus are released and passed to the pituitary gland via blood vessels.
What is neurohypophysis?
The interaction between the hypothalamus and the posterior pituitary gland.
Hormones produced by the hypothalamus are passed to the pituitary gland via nerve axons.
Trophic hormones tend to be..
Inhibiting or releasing (i.e. controlling actions)
What two hormones are produced in the nuclei of the hypothalamus?
Antidiuretic Hormone and Oxytocin
How many nuclei has the hypothalamus got?
2
What hormones does the thyroid hormone secrete?
T3 & T4 (thyroxine)
Calcitonin.
What conditions are caused by hypothyroidism?
Cretinism and myxoedema.
Myxoedema associated with alopecia and can be reversed by introducing the thyroid hormone.
What conditions are caused by hyperthyroidism?
Grave’s disease. Autoimmune disease. Causes exophthalmos.
What is the purpose of the parathyroid hormone?
Regulate blood calcium.
What controls insulin secretion?
Glucose dependant insulinotropic peptide, vagus nerve activity.
Name the actions of glucagon:
Glycogenolysis and gluconeogenesis in the liver
What controls glucagon secretion?
Cholecystokinin.
Autonomic nerve activity.
What characterises type 1 diabetes?
Reduced insulin secretion due to destruction of beta cells.
What characterises type 2 diabetes?
Decreased sensitivity to insulin. Common in overweight individuals.
What hormones do the adrenal glands secrete? Name them.
Cortex hormones: Corticosteroids. Aldosterone, cortisol and androgens.
What type of cortex hormone is aldosterone?
Mineralocorticoids
What type of cortex hormone is cortisol?
Glucocorticoid
What is the action of cortisol?
Metabolic effects.
Anti-inflammatory.
What is the action of aldosterone?
Promotes reabsorption of sodium and water in the kidney.
Increases hydrogen and potassium excretion.
What type of cortex hormone is androgen?
Gonadocorticoid.
What is the action of the androgens?
Growth and sexual characteristics.
Pubertal growth.
What does the adrenal medulla produce?
Adrenaline.
What is the adrenal medulla controlled by?
Pre-ganglionic sympathetic nerves.
What does the endocrine response to stress depend on?
Duration, severity of the stimuli and the effectiveness of the response.
Name the stages of the general Adaptation Syndrome (stress).
Alarm, resistance and exhaustion.
What are the components of an alarm response (stress)?
Neural and hormonal.
What is the neurological alarm response controlled by (stress)?
Sympathetic nerves.
What happens in the neurological response (stress)?
Increased cardiac output: (Increased heart rate and ventricular contractility)
Redistribution of cardiac: output. (Blood redirected from gut to muscle)
Glycogen breakdown.
Adrenal release.
What hormones are released in the hormonal component?
Adrenaline and glucocorticoids (cortisol)
What is the function of adrenaline?
Prolongs the action of sympathetic nerves.
What are the actions of glucocorticoids?
Increased energy production from glucose. Gluconeogenesis of amino acids and fats.
Anti-inflammatory.
Immunosuppression.
What is the function of corticosteroid therapy?
Suppresses the body’s natural response, corticotropin and adrenocorticotropin hormone.
What happens in long term use of corticosteroids?
Disrupts the normal stress control mechanisms.
What is stress analgesia?
How does it work?
Pain diminished during physical stress.
Suppression of nociceptors and pain.