ES. Glands and Hormones Flashcards
what is the connection between the hypothalamus and the pituitary gland?
infundibulum
what is the function of the hypothalamus?
thermoregulation
hormone secretion
circadian rhythms
motivation
emotions
what are the 2 groups of hormones secreted by hypothalamus?
primary and throphic
how does thermoregulation work?
- low core body temp recognised by thermoreceptors in hypothalamus
- they compare temp with ‘set point’
- effectors increase heat production and decrease heat loss
how does the hypothalamus have a role in regulating the circadian rhythm?
responding to day/night cycles
where do hormones produces in the hypothalamus pass?
posterior pituitary along nerve axons
where are hormones produced in the hypothalamus released into circulation?
in posterior pituitary
the hypothalamus produces releasing hormones. where do these pass and via what?
to anterior pituitary via blood vessels
the hypothalamus produces releasing hormones. what do these trigger?
secretion of hormones from anterior pituitary
name hypothalamic hormones.
corticotropin releasing hormone
gonadotropin releasing hormone
thyrotropin releasing hormone
growth hormone releasing hormone
somatostatin (GH inhibiting hormone )
which hormones are related from the anterior pituitary gland?
adrenocorticotrophic hormone
follicle stimulating hormone
luteinising hormone
thyroid stimulating hormone
growth hormone
prolactin
what does it mean if it is a hypothalamic releasing hormone?
have trophic effect and acts somewhere else after release of second hormone
what clinical effect would removing cortisol quickly have on a patient?
may lead to hypersensitivity to adrenaline
what does the stimulus do to the hypothalamus in feedback?
causes it to release releasing hormones to stimulate pituitary gland
what does negative feedback of thyroid hormone effect?
anterior pituitary and hypothalamus
how are antidiuretic hormone and oxytocin produced and where?
where do they pass?
by neurons in the hypothalamus
pass along axons to posterior part of pituitary
what are the 2 nucleuses in the pituitary gland?
supraoptic and paraventricular
where does the antidiuretic hormone act and what does it do?**
kidney - water reabsorption in collecting ducts
what oxytocin do?
- contraction of uterus (parturition)
- milk ejection
what does prolactin do?
breast development and milk production
……………
where is the thyroid gland found?
in neck anterior to trachea
which hormones are produced in the thyroid gland?
thyroid hormones, T3, T4, calcitonin
what does calcitonin do?
regulated calcium levels
what cells produce calcitonin?
parafollicular c cells
what is T3 thyroid hormone?
tri-iodo-thyronine
what is T3 thyroid hormone?
tri-iodo-thyronine
what does T4 thyroid hormone in respect to T3?
precursor for T3
what do T3 and T4 thyroid hormones do?
- increase metabolic rate of cells
- determines basal metabolic rate
- essential for normal metal and childhood growth
- permissive effect on action of adrenaline by up regulating adrenoreceptors
what are the 2 main disorders of the thyroid hormone?
under or over secretion
what is undersecretion of the thyroid hormone called in adults and children?
hypothyroidism = adult
cretinism, myoxydema = child
what are the 2 terms to describe over secretion?
hyperthyroidism
graves disease
what is simple goitre?
thyroid swelling associated with iodine deficiency
- low levels of thyroxine results in increases secretion of TSH
how do you fix myxodema?
treat with thyroxine
how many parathyroid glands is there and where do they lie?
4-5
- deep surface of thyroid gland
how much pancreatic tissue is made of islets of langerhans?
1-2%
what 3 hormones do islets of langerhans produce?
insulin
glucagon
somatostatin
what is insulin released in response to and what does it do?
response to raised blood glucose level
acts to lower blood glucose
insulin facilitates glucose entry into what..?
muscle cells, adipocytes (glucose uptake by liver is mot insulin dependent)
insulin promotes to formation of what?
glycogen
triglycerides
facilitates protein synthesis
how do we promote insulin secretion?
high blood glucose
high blood amino acids
glucose dependent insulinotropic peptide
vagus nerve activity
how do we inhibit the secretion of insulin?
adrenaline
sympathetic nerves
somatostatin
why is glucagon released and what does it act on?
response to low blood glucose concentration
acts to raise blood glucose
what actions does glucagon do?
- glycogenolysis in liver
- gluconeogenesis in liver
- lipolysis and ketone synthesis
how do we promote the secretion of glucagon?
low blood glucose
high blood amino acids
cholecystokinin
autonomic nerve activity
how do we inhibit secretion of glucagon?
insulin
somatostatin
what metabolic changes take place in diabetes mellitus?
gluconeogenesis
lipolysis
what is diabetes mellitus?
elevated blood glucose concentration due to decreases glucose uptake by cells
what are the clinical features of diabetes mellitus?
polyuria (increased urine production)
polydipsia (increased fluid intake, thirsty)
glycosuria (glucose in urine)
diabetic neuropathy
skin and oral diseases (periodontitis, xerostomia)
what type of diabetes is insulin dependent from onset?
type 1
what type of diabetes is insulin independent from onset?
type 2
describe the insulin secretion in type 1 and type 2 diabetes?
type 1 = decreased
type 2 = normal
how does the target cell respond to insulin in type 1 and type 2 diabetes?
type 1 = normal
type 2 = decreased
which type of diabetes is considered late onset?
type 2
which type of diabetes is related to being overweight?
type 2
what is the treatment for type 2 diabetes?
diet
oral hypoglycaemic agents
what is the treatment for type 1 diabetes?
insulin injections and control diet
where do the adrenal gland lie?
on top of the kidneys
what are 3 cortex hormones?
aldosterone
cortisol
androgens
where is cortisol produced in adrenal cortex?
zona fasciculata
what are the actions of cortisol?
metabolic effects
permissive effects
antiinflammatory, imunosuppressant
where is aldosterone produced?
zona glomerulosa
what is the release of aldosterone controlled by?
reninangiotensin system
what are the actions of aldosterone?
- promotes reabsorption of Na+ and H20 in kidney
- increases excretion of H+ and K+
where do gonadocorticoids come from?
zona fasciculata and reticulates of adrenal cortex
what do androgens contribute to?
growth and pubertal growth spurt
what can excess glucocorticoids lead to?
bushings syndrome
what can excess androgens lead to?
adrenal-genital syndrome
what controls the adrenal medulla?
pre-ganglionic sympathetic nerves
what do adrenal medulla cells produce? what does this do?
adrenaline
- augments action of sympathetic nervous system
what happens as a result go adrenal insufficiency? what is this?
Addisons disease
- decreased adrenal function and reduced levels of adrenal hormones:
glucocorticoids
mineralocorticoids
