Endocrine Intro and Appetite Flashcards
what do nociceptors detect
pain
in a control system what is the afferent pathway
communication between the receptors and control centre through the nervous system or endocrine system
in a control system what is the efferent pathway
communication between the control system and the effector to give a response
what is a set point
the parameters in which a variable must lie
what is the circadian/diurnal rhythm
where set points change thoughout the day during a 24 hour period
what is melatonin and where is it produced
a hormone which is involved in the biological clock and is released from the pineal gland
what is negative feedback
a response in a way to reverse and change in the system
what is positive feedback
a response which increases the direction of the variable to give a rapid change
where are osmoreceptors found
hypothalamus
what is the difference between osmolarity and osmolality
osmolarity = number of osmoles per litre of solution osmolality = number of osmoles per Kg of solution
what is an osmole
the amount of substance that dissociates in solution to form 1 mole of osmotically active particles
what is the reference range for serum osmolality
275-295 mOsmol/kg
what are the 9 endocrine organs
- hypothalamus
- pituitary gland
- thymus
- parathyroid
- thyroid
- gonads
- pancreas
- adrenal glands
- pineal
what are the 4 classifications of hormones
- peptide
- steroid
- amino acid
- glycoproteins
which classifications of hormones are water and lipid soluble
water soluble: peptide and glycoprotien hormones
lipid soluble: steroid and amino acid
name 3 amino acid hormones deriving from tyrosine
adrenaline, noradrenaline, thyroid hormones
name 3 steroid hormones
cortisol, aldosterone, testosterone
where are steroid hormones derived from
cholesterol
how are lipid soluble hormones transported in the blood
by being bound to proteins which increases their stability and solubility and allow them to be a readily available reserve
what 3 factors determine the hormone levels in the blood
- rate of production
- rate of delivery
- rate of degradation
outline how tyrosine kinase receptors work
following binding of a ligand dimerisation occurs which allows for autophosphorylation of the receptor. the receptor can then recruit proteins and activate them through phosphorylation to give a repsonse
give an example of a tyrosine kinase receptor
insulin receptor
where is the appetite control centre located
in the hypothalamus
which part of the hypothalamus controls appetite
the arcute nucleus (collection of neurones)
what types of neurones are found in the arcute nucleus
primary and secondary neurones which respond to signals from the body
what are the 2 types of primary neurones in the arcute nucleus
type I = stimulatory neurones containing NPY and AgRP which promote hunger
type II = inhibitory neurones containing POMC, alpha-MSH and beta-endorphin
what hormones from the gut signal to the hypothalamus about hunger
- Ghrelin from the stomach stimulate appetite
- PYY from the ileum supresses hunger
name 3 hormones released from in the body (apart from the gut) which control hunger
- Leptin from the adipocytes stimulate inhibitory neurones and inhibits excitatory neurones in the arcute nucleus to suppress hunger
- insulin supresses hunger
- amylin from beta cells in the pancreas suppress appetite
