L1 - Intro to endocrinology & hypothalamus and pituitary Flashcards
True or false: endocrine glands are ductless glands that release their secretion into the blood
false
True or false: the sweat gland is endocrine?
false
is the endocrine system slow or fast?
slow
what type of feedback control is thyroid hormone regulated by
negative
True or false: The increase in the blood glucose concentration after feeding cause hypothalamus/anterior pituitary to secrete a tropic hormone which act on pancrease to release insulin.
false - pancreatic islet cells detect this change
t/f: Water soluble hormones require plasma protein binding for transportation to its site of action.
false
t/f : Hormones with high lipophilicity have longer duration of action
true
where do water insoluble hormones usually have their receptors?
cytoplasm/nucleus of target cell
what is the common precursor for all steroid hormones?
cholesterol
Refers to an action in which chemical messenger is released to have effect on neighbouring cells
paracrine
Refers to an action in which chemical messenger is released to have effect on the same cell which released the messenger
autocrine
Refers to an action in which chemical messenger is released into the blood to have effect on distant cells
endocrine
which part of the brain is the main control centre in the brain responsible for homeostasis
hypothalamus
Hypothalamic-hypophyseal portal veins are the blood vessels between two capillary beds; - between which 2 organs
hypothalamus and anterior pituitary
what are endocrine glands?
ductless - secrete into blood
what are exocrine glands?
secreted into ducts
which type of glands are used for homeostasis - long acting?
endocrine
what is a hormone?
chemical messenger secreted into the blood to act on distant target cells
what are endocrine mediators?
released into blood to have action on distant cells
what are autocrine mediators?
released to have effects on the same cell
what are pararine mediators?
released to have effects on neighbourig cell
term for hormones released by neurones?
Neurohormones
what are autocoids?
chemical messengers which have a paracrine effect
what is a neuromodulator?
chemical messenger which acts on neurons at non-synaptic sites to bring changes in the nerve cell
3 types of hormones?
- peptides & proteins
- steroids
- derivatives of AA tyrosine
examples of peptide and protein hormones?
pituitary, insulin, glucagon, parathormone
4 places where steriod hormones are produced in the body?
- adrenal cortex
- ovaries
- placenta
- testis
which type of hormones are T3 and T4?
group 1 derivatives of AA tyrosine
what type of hormones are epinephrine and norepinephreine?
group 2 catecholamines derivatives of AA tyrosine
3 steps in protein and peptide synthesis?
- pre-prohormone synthesised by ER
- prohormone - packages into secretory vesicles by golgi
- active hormone stored in vesicle until released
are peptides hydrophobic or hydrophilic?
hydrophilic
are steriod hormones hydrophobic or hydrophilic?
hydrophobic
why do steriod hormones bind to plasman proteins in the blood - why dont peptides?
as steriod hormones are hydrophobic
which type of hormones are able to diffuse into target cells? why? why cant the others?
steriod hormones can - there are receptors for these hormones in the target cell cytoplasm/DNA
protein hormones cannot - as the receptors are on the cell surface
3 steps of steroid hormone synthesis
- cholesterol
- pregenolone
- other steriod hormones
how do steriod hormones function
activate a specific gene in target cell - produce specific enzyme
do steriod hormones have a long or short duration of action?
short and long
what are group 1 AA derivative hormones similar to?
steriods
what are group 2 AA derivative hormones similar to?
peptides and proteins
where are T3 and T4 stored?
thyroid gland
what detects thyroid hormone incretion/depletion?
antierior pituitary
what stimulates the thyroid gland to secrete hormones?
TSH
what releases TSH?
ant pit
what cells detect changes in plasma glucose
pancreatic islet cells
what intrinsic receptors input to the hypothalamus
- thermoreceptors
- osmoreceptors
which 2 ways can the hypothalmus respond to inputs?
autonomic NS and endocrine signals
describe blood flow in hypohyseal portal blood system
heart internal carotid art superior hypophyseal art capillary 1 - hypothalamus hypophyseal portal vein capillary 2 - ant pit hypophyseal vein heart
what is the hypophysis?
pituitary gland
which bony cavity does the pituitary gland lie in?
sella turcia
the majority of hormones releases from pit gland are tropic - what does this mean?
act on other endocrine glands to release their hormones
what controls the secretion of the pit gland?
hypothalamus
2 portions of pit gland (give both names)
- anterior - adenohypophysis
2. posterior -neurohypophysis
where does the anterior pit gland originate from?
Rathke’s pouch
the posterior pituitary contains 2 neurones within cell bodies - what are these?
supraoptic nuclei
paraventricular nuclei
what hormone is secreted by supraoptic nuclei?
ADH
what does ADH work on
kidneys
what hormone is secreted by paraventricular nuclei
oxytocin
what cells secrete growth hormone?
somatotropes
what cells secrete adrenocorticotropin?
corticotropes
what cells secrete TSH?
thyrotropes
what cells secrete LH and FSH
gonadotropes
what cells secrete prolactin ?
lactotropes
function of growth hormone
cause liver to produce somatomedine
function of adrenocorticotropin
cause adrenal gland to secrete NE and E
function of FSH + LH in males
testes to produce inhibin + testosterone
function of FSH + LH in females
ovaries to produce oestrogen, progesterone, inhibin
2 types of hormones released by hypothalamus - where do they have an effect?
inhibiting or stimulating - by ant pit
how do hypothalamic hormones reach the ant pit?
hypothalamic-hypophyseal portal veins (in the blood stream)
what is an endocrine axis?
pathway of how endocrine organs produce a specific hormone
what 3 things does an endocrine axis contain?
- hypothalamis factor (the hormone)
- pituitary target cell (cells which the hypthalamus acts on)
- target cell (which release the target hormone)
