Introduction to Endocrine Systems Flashcards
why can some diseases look different depending on the patient
the time in the patients life when it manifests as well as the patients own response can impact how the disease appears phenotypically. eg childhood versus adulthood manifestation
what is diastema
gaps between the teeth
breakdown the key steps of endocrine secretion
chemical secreted at low concentrations into the bloodstream by a cell or a group of cells
it is sent to all parts of the body via the bloodstream
it only acts on cells with the correct membrane receptor protein that targets cells
what are the key features of an endocrine secretion
it acts on many places at the same time
it is affected by the strength of circulation
stopping hormonal response requires removal of the hormone from circulation
what is the concentration unit of hormones
femtomoles
describe humoral communication
communication by hormones on many different cells in the body
coordinated, body wide actions
it is slow to act and the effect persists
what are the two main classifications of hormoens
steroids and non steroids
what are the non steroid hormone sub categories
amino acid derivatives
peptides
glycoproteins
which kind of hormone can enter the cell and why
steroid hormones as they have a lipophilic ring that can penetrate the membrane
what are the steroid hormones
cortisol
aldosterone
testosterone
oestrogen
progesterone
what are the amino acid derivatives
amines and iodinated amino acids
describe some hormones that are amines
adrenaline
noradrenaline
melatonin
describe some hormones that are iodinated amino acids
triiodothyronine
tetraiodothyronine (thyroxine)
what are the two classifications for peptide non steroid hormones
short chain and long chain
what are the short chain peptide hormones
antidiuretic hormone
oxytocin
melanocyte stimulating hormone
somatostatin
thyrotropin releasing hormone
gonadotropin releasing hormone
atrial natriuretic hormone
name the long chain peptide hormones
growth hormone
prolactin
parathyroid hormone
calcitonin
adrenocorticotropic hormone
insulin
glucagon
gi tract hormones
describe how hormones are produced
many are made in an inactive form first
pre-prohomrones become prohormones in the endoplasmic reticulum
the prohormone is packaged in golgi apparatus and is converted to the active hormone here
the active hormone is then secreted from vesicles
describe the insulin structure
complex structure that takes time to be made and therefore must be stored
can prohormones generate responses
yes, although they are much less potent as their activated form
why is high insulin concentration fatal
can lead to hypoglycemia of the brain
the brain needs glucose to survive, so without it there is death
what is a high concentration of prohormones in the blood associated with
high release of their activated hormones
what are glycoproteins
proteins with attached carbohydrate groups to the amino acid
what are some glycoprotein hormones
follicle stimualting hormone
luteinizing hormone
thyroid stimulating hormone
chorionic gonadotrophoin
what are some local tissue hormones
prostoglandins
leukotrienes
thromboxanes
what are the functions of local tissue hormones
blood flow regulation
haemostasis
mucosal protection in the stomach
inflammation
why are local tissue hormones not really hormones
they are not released into the circulation
how do most non steroid hormones bring about responses in cells
via second messenger systems within the target cells
the steroid hormones cna pass through the outer cell membrane and directly reach the intracellular receptors
what are the two common second messengers
cAMP and Ca++
what is the pathway of hormone secretion
endocrine cells are stimulated to produce the hormone into the bloodstream (some need carrier proteins in order to move through the bloodstream)
the hormones work on the target cell
some are excreted throguh the kidneys and some are metabolised by the liver
metabolism produces raw materials that can be recycled for new production cycles
how do steroid hormones bring about responses
they pass the membrane and work on the cell machinery to produce a protein
direct action will take time as the proteins are being produced
can a patient be on cortisol and still have surgery
it is risky and surgeons to ask the gp to take the patient of cortisol for the surgery to make it safer
what is negative feedback
a normal biological response that slows or stops a reaction when it reaches a certain level
give an example of a negative feedback loop
The parathyroid hormone will raise plasma calcium concentration and inhibit the release of parathyroid hormone. This is a negative feedback loop.
what is receptor regulation
the sensitivity of target cells is related to the number of membrane receptors
more receptors gives upregulation and less receptors gives downregulation
describe upregulation
there are more receptors so there is a higher chance the hormone will bind
describe downregulation
there are less receptors so there is reduced chance of binding
what can lead to hyperfunction
excess production and secretion
upregulation of receptors
failure to metabolise a hormone
what can lead to hypofunction
decreased production and secretion
downregulation of receptors
receptors not functioning
