Unit 5 Flashcards
what is a hormone ?
a chemical messeger secreted into the blood by cells
what is the difference between exocrine vs endocrine glands
exocrine gland has a duct and it secreted on to the epithilium surface
endocrine has no duct and secretes via blood
what the 4 functions of a hormone
- growth
- metabolism
- regulates internal enviroment
- reproduction
what happens when you remove the testes from a chicken ?
it reduced masculine behaviour and phenotype
what are 4 things about the classical hormone ?
- secreted from epithilian tissue that make glands
- secreted into blood
- targets are far
- acts at low concentration
what are 3 things about non classical hormones?
- secreted by neurons, immune or endocrine cells
- acts locally
- can be a neurotransmitter
what are the target cells for a hormone ?
must have receptors for that specific hormones and they can increase and decrease sensitivity of a hormone by increasing/ decreasing receptor expression
what are 3 ways to remove hormones from receptors
- inactivtation of hormone through kidney
- proteases break them down
- endocytosis by target cells
what are 4 key facts about peptide/protein hormones
- dont live long ,short half life
- largest group of hormones
- hydrophilic- bind to membrane receptors
- fast signal transduction
where are peptide/protein hormones made ?
in the secretory pathway
how are amine hormones made ?
it is made from trytophan or tyrosine
what hormone is tryptophan and where is it from ?
melatonin hormone an from pineal gland(brain)
what hormones do tyrosine make
- catechol amine which are neurohoromones etc dopamine epinehprine
- thyroid hormones
what are thyroid hormones and where is it made ?
an intercellular hormone t4 and t3 that are made via epithelial cell in the thyroid gland
what differentiates thyroid hormones and catechol amine
based on iodine molecules as thyroid hormones have them
what are 4 facts about steroid hormones?
- made in only a few organs etc adrenal cortex , gonands and placenta bc they must have cleaving functionality
- they are small
- need to be cleaved
- long half lives
how are steriods made
they are imported or made within the cells they are made on demand by increased enzyme activity and are usually bound to protein and have lots of smooth ER
what type of steriods does the adrenal gland produce from cholesterol?
cortisol and aldosterone
what type of steriods does the ovaries produce from cholesteral
estradial and progesterone
what type of steriods does the gonads produce ?
testerone (DHT)
what is the steriod pathway ?
- intracelluar ligand
- bind to receptors
- activates transcription factors
- makes new protein
etc aldestrerone
what is an example of the endocrine reflex pathway?
- hyper kalemia ( high K+)
- adrenal cortex
- aldersterone. (travels blood)
- kidenys
- save na + loose k +
6 decrease potassium
where are key neurohormone made ?
adrenal medulla -epinphrine
hypotalamus - vasopressin
what is made in the posterios pitutary gland ( neuro hypophysis)
vasopressin through neurons then released into blood
what happens in the anterior pitutary gland ?
- neurohormones relase of hypothalamus
- enter 1st capillary bed ( blood )
- enter 2nd cap bed via portal vienss
- then go to target organs
what are the 3 tiers in the hypothalami pitutary axis?
tier 1; releasing hormones
tier 2: trophic hormone
tier 3 : target gland
what is the pathway for hypocalemia (low ca+)
- decrease in ca
- parathyroid integration centre
- release og parathyroid H
- increase in calcum
what are the three intregration centres involved in the hypotahalamic pititary axis ?
endocrine cells
adrenal cortex
thryoid gland
what are the 3 feedback loops in the hypothalamus with tiers?
Feedback 1:
tier 1: release of TRH hormone from hypothalamus
tier 2 : trophic hormones TSH from anterior pitituary glang
tier 3 target gland thyroid gland
LAST :release of t3 t4 thyroid hormone
Feedback 2:
tier 1: release of CRH hormone from hypothalamus
tier 2 : trophic hormones ACTH from anterior pitituary glang
tier 3 target gland adrenal cortex
LAST :release of cortisol
Feedback 3:
tier 1: release GnRH from hypothalamus
tier 2 : trophic hormones FSH LH. from anterior
tier 3: target gland gonands
LAST: releaese of andregon , estrogen, progestrogen
what is synergism and what is an example ?
a combined effect that is greater than the indiviudal effect
an example would be Glucagon, Epinephrine and cortisol together give high glucose level but sepereatly dont do much
what is permissiveness and 2 example ?
a hormone is required by is not enough for the full affect and that can be the addition of cortisol to make blood glucose level bc we just two it doesnt do much you need all 3 to give the full affect and the thyroid hormone
what is antagonism?
a substance the oppose the action of another etc when glucagon frees a glucose to get the levels up
what is hypersecretion and example
it is issues with feedback that makes tumors in glands and for example at the pitutary level its extra sectretion of ACTH TSH ,FSH LH and it grows the gland
what is hyposcretions and example
when your unable to produce hormone or less of the hormone your tier 2 hormones up etc if you cant make cortisol your ACTH goes up or defiency in iodine cant make t3 t4 you TSH. goes up
what is an example of abnormal responsiveness in target tissue ?
diabetes insipidis is up your receptors are mutated which lead to VP messing up and you piss more water out
