A & P - Endocrine system Flashcards
what is the function of the endocrine system?
maintaining homeostasis
name some examples of homeostatic regulation that the endocrine system is involved in
water / electrolyte balance
blood pressure
body temp.
how does the endocrine system regulate homeostasis?
using chemicals (hormones)
- proteins/peptides
- steroids
does the endocrine system quicker or slower than the nervous system in maintaining homeostasis?
slower
what are hormones?
chemical substance produced by the body that controls and regulates the activity of certain cells or organs
name three hormone groups
peptide (amino acid based)
steroid
amine (amino acid based)
describe how a peptide hormones works
binds with membrane receptors
how do steroid hormones work?
bind with the cytoplasmic / nuclear receptors
how do amine hormones work?
similar to steroids - activate transcription of specific genes
what do exocrine and endocrine glands have in common?
both synthesise and store chemical messengers
which glands have no ducts?
endocrine
where do exocrine and endocrine glands release their hormones?
exo - surface of epithelium
end - into blood
what is the function of the hypothalamus?
regulation - maintaining homeostasis
which releasing hormones does the hypothalamus secrete?
TRH - Thyrotropin releasing hormone PRF - prolactin releasing factor PRIF - prolactin release inhibiting factor CRH - Corticotropin-releasing hormone GnRH - gonadotropin-releasing GHRH - growth hormone releasing hormone SS - somatostatin
what is the hypothalamus the link between?
the endocrine and the nervous system
which hormones are stimulated in the anterior pituitary by the releasing hormones secreted from the hypothalamus?
TSH - thyroid stimulating hormone PRL - prolactin ACTH - Adrenocorticotropic Hormone LH - luteinising hormone FSH - follicle stimulating hormone hGH - human growth hormone
where are the hypothalamus, pituitary gland and pineal gland located?
brain
how many parathyroid glands are there and where are they located?
4 - neck
where are the adrenal glands located?
on top of kidneys
which hormone stimulates the thyroid gland?
TRH - thyroid stimulating hormone
what is needed to stimulate T3 and T4 production?
iodine
what is the position of the thyroid gland?
sits below Adam’s apple
which hormone group do T3 and T4 belong to?
amine
where are the T3 and T4 receptors found in the cell?
nucleus
mitochondria - gene expression- increases ATP production
cytoplasm
what are the functional outcomes for T3 and T4?
increased:
metabolic rate
temp.
HR / resp. rate
what do the C cells in the thyroid gland produce?
calcitonin
what does calcitonin do and how?
lowers calcium and phosphate levels in blood by decreasing amount released from bones and increasing excretion by kidneys
what does thyrotropin-releasing hormone (TRH) stimulate?
thyroid stimulating hormone (TSH)
what does thyroid stimulating hormone (TSH) do?
stimulates breakdown of thyroglobulin into T3 and T4.
what is thyroglobulin the precursor of?
T3 and T4
what is T4 and what is its structure ?
thyroxine - has 4 iodide ions
what is T3 and what is its structure ?
tri - iodothyronine - has 3 iodide ions
what happens to T4 at the tissue site?
it converts to T3 (90%)
where is the optic chiasm?
above anterior pituitary gland
what travels to the anterior pituitary to release hormones?
blood vessels
what travels to the posterior pituitary to release hormones?
nerves
what does the adrenal gland secrete?
medulla - adrenaline / noradrenaline
cortex - steroid hormones (minerocorticoids and glucocorticoids)
what does the pancreas secretes?
insulin - decreases blood glucose levels
glucagon - increases blood glucose levels
which hormones use the cAMP mechanism?
adrenaline / Noradrenaline ADH ACTH FSH LH TSH PTH Calcitonin Glucagon
how is Adenylate cyclase activated in peptide hormone action?
cAMP acts as 2nd messenger
opens ion channels and activates enzymes
what is the action of a minerocorticoid?
alters the sodium balance
give an example of a minerocorticoid
aldosterone
where is aldosterone released from?
adrenal cortex
how does aldosterone work?
increases osmolality of blood by causing Na+ (sodium) reabsorption from distal convoluted tubule and medullary collecting ducts in the kidney
what is a paracrine response?
hormone effect restricted to local environment
what is an autocrine response?
self stimulation through cellular production of hormone
name some other tissues that are not ‘classic’ endocrine glands but do secrete hormones
heart - ANP kidney - EPO, calcidiol brain - BNP small intestine - CCK, secretin pineal gland - melatonin parathyroid gland - PTH placenta - hCG thymus - thymosin
name some things that the endocrine and the nervous system both use
chemicals - hormones / neurotransmitters
adrenaline
how does the response of the endocrine system differ to that of the nervous system/
endocrine is slower and acts over long distances but the nervous system is faster and acts over short distances
what is the hormonal role of adrenaline / Noradrenaline?
released by sympathetic nervous system and by adrenal medulla
what is the neural role of adrenaline / Noradrenaline?
released by autonomic nervous system as a neurotransmitter
