Endocrine homeostasis Flashcards
endocrinology=
study of glands and the hormones they produce
2 types of glands
exocrine
endocrine
2 types of hormones based on solubility
Lipid soluble
Water soluble
how are lipid soluble hormones transported
Need transport protein
where are lipid hormone receptors
inside the cell
where are water soluble hormones receptors
in cell membrane
3 different hormone structure
Polypeptide
Amino acid
Steroids
2 polypeptides
Anterior pituitary hormones
Secretin
2 amino acids
catecholamines
Thyroid hormones
2 steroid hormones
adrenal cortical and gonadal hormones
2 hormones derived from tyrosine
catechloamines
thyroid hormone
where does the hypothalamus lie below
the thalamus
where does the pituitary gland sit
sella turicia
hypothalamus connected to the pituitary by the
pituitary stalk
What is the hypothalamal hypophyseal portal system
network of capillaries that join the hypothalamus to the pituitary gland
two main hormones released from the posterior pituitary
Anti-diuretic hormone
Oxytocin
where are the posterior pituitary hormones synthesised
in the hypothalamus
HPA axis =
hypthalamus produces CRH—> anterior pituitary to produce ACTH—> adrenal cortex to produce cortisol
cortisol negative feedback of CRH and ACTH
CRH=
corticotropin releasing hormone
ACTH=
adrenocorticotropic hormone
cortisol functions as a
stress hormone
primary adrenal insufficiency=
lesion in adrenal cortex
secondary adrenal insufficiency=
lesions in the anterior pituitary
tertiary adrenal insufficiency=
lesions in the hypothalamus
another name for primary adrenal insufficiency
addison’s disease
what does addison’s disease cause
decreased cortisol levels
increased CRH and ACTH
what can primary adrenal insufficiency (addison’s disease) cause
hyper-pigmentation
what causes hyper-pigmentation
ACTH stimulating melanocyte to make lots of melanin
in which adrenal insufficiency are all 3 hormone levels low
tertiary adrenal insufficiency
what do you do if you suspect insufficiency
stimulate
what do you do if you suspect over functioning
suppress
how to diagnose addison’s disease
synacthen stimulation test (synthetic ACTH)
diagnosis of secondary adrenal insufficiency by
insulin stress test
explain insulin stress test
insulin= hypoglycaemia= stress response= increase CRH= normally increase in ACTH and cortisol
cushing syndrome=
general symptoms of increased cortisol levels
characteristics of hypercortisolism
loss of hair
weight gain
hyperglycaemia
protein depletion (poor wound healing)
sources of hypercortisolism
primary
secondary
name of secondary hypercortisolism
cushings disease
what 2 diseases cause hyper-pigmentation
primary adrenal insufficiency
secondary hypercortisolism
levels in cushing syndrome
increased cortisol
increased ACTH
decreased CRH
levels in primary hypercortisolism
increased cortisol
decreased ACTH
decreased CRH
test for cushing’s syndrome
dexamethasone suppression test
HP-Thyroid axis
TRH from hypothalamus—->TSH from anterior pituitary—-> thyroid hormones from thyroid
2 thyroid hormones
Triiodothyronine (T3)
thyroxine (T4)
HP gonadal axis =
GnRH from hypothalamus —> anterior pituitary release LH and FSH —> increases in testosterone in males and increase in oestrogen/ progesterone in females
primary hypogonadism levels
decreased oestrogen and testosterone
increased LH and FSH
secondary hypogonadism levels
decreased oestrogen/testosterone
decreased LH anf FSH
prolactin=
a milk hormone made by the anterior pituitary
prolactin production is a type of
positive feedback
what is a prolactin inhibiting factor
dopamine
metaclopromide=
dopamine antagonist
what can a side effect of metaclopromide cause
hyperprolactinemia—> galactorrhoea
bromocriptine=
dopamine agonist
growth hormone pathway=
GHRH released by hypothalamus—> pituitary GH—> liver to produce IGF-1
IGF-1=
insulin-like growth factor
before epiphysis has grown excess GH=
gigantism
after epiphysis has grown excess GH=
acromegaly (broad/wide features of hands ect)
what suppresses GHRH
somatostatin
where is somatostatin produced
hypothalamus (also pancreas)
how to treat excess growth hormone syndromes
Octreotide (somatostatin analogue)
how are posterior pituitary hormones transported in the blood
neurophysins hormones
name 2 posterior pituitary hormones
vasopressin (ADH)
Oxytocin
what does vasopressin do
contracts the blood vessels to maintain blood pressure
and conserves water
what inhibits ADH
alcohol (causing excess urine production)
treatment of diabetes insipidus
synthetic ADH (desmopressin)
what mechanism does oxytocin use
positive feedback
what does oxytocin cause
contraction of uterus smooth muscle
