Principles of endocrine control Flashcards
what is endocrinology
study of hormones
what is secretion
the biochemical release from a particular type of cell upon stimulation
endocrine gland
secretions enter the bloodstream - ductless gland
exocrine
glands with ducts that channels its secretion ( secretes all enzymes that break down all proteins and lipids
what is an autocrine gland
secretion acts on the cell that secreted it- hormonal or chemical
( GF secrete from cancer cells such as VEGF and IL-1)
Paracrine gland
localised action when chemical secreted locally and affects another cell in that tissue such as histamines
what are neurohormones
and example
Neurohormones: hormones secreted by hypothalamus and pituitary, example vasopressin
what are hormones
is a chemical messenger secreted into blood by endocrine glnds in reposne to an appropriate signal and exerting their effects on target cells that have receptors that bind witht the hormone
how do we classify hormones
Based on their solubility
Hydrophilic or water soluble
Lipophilic or lipid soluble
Based on their structure
Peptides - chain of aa
Amines - derviateves of aa, tryptophan or tyrosine - catecholamines, indoleamines and thyroid hormone - can be lipid or water soluble
Steroids - cholesterol derived lipids eg. testosterone - always lipid soluble
where do peptides bind to cells
Travel in blood in solution
Cannot enter cells - lipid bilayer cell membrane
Bind to cell surface receptor
Trigger event on inside surface of membrane - second messenger system
Fast acting
how do steroids bind to cells
Travel in blood bound to plasma proteins
Enter cells easily
Intracellular receptor
Act on DNA to alter cell function
Slow acting - transcription delay - aware when treating someone with steroid hormone as slow adcting
how are steroids made
Produced by modification of cholesterol molecule by enzymes
peptide hormone signal transduction used what type of receptor and second messenger
g protein and coverts ATP into cAMP which further tenets leading to cell response such as phorpylating proteins
adrenaline , noradrenlaine , glucagon . FSH and LH , TSh calcitonin PTH and ADH all are G protein coupled receptor complexes what is their second messenger
Cyclic AMP
Atrial nature tic hormone and NO are G protein what second messenger do they use
Cyclic GMP
what second messenger does insulin use
protein kinase ( tyrosine kinase apthway ) prolactin and GH use protein kinase JAK pathway)
name some human endocrine organs
Hypothalamus CNS pituitary CNS thyroid paarathyroid DRENAL CORTEX AND MEDULLA \KIDNEY STOMACH pacretatic islets duodenum and ovary and testes
regulatory role of endocrine system
Metabolism
stress
Growth and development
coordination
how does the hypothalamus connect to the pituitary
pituitary stalk
What hormones are stored in posterior pituitary
ADH
oxytocin
CRH TRH somatostain GnRH GhRH PRH dopamine produced by what
Hypothalamus
GH TSH ACTH LH FSH produced by what prolactin
Anterior pituitary
what are the roles of the posterior pituitary
regulation of overall water balance
uterine contraction
ejection of milk
function of oxytocin
contractions of the womb
increases production of prostaglandins increasing contraction further - PGF2alpha
maybe ejection of milk too
romantic and bonding
ACTH stimulates what
adrenal gland - to produce adrenocorticosteriods
Prolactin stimulates what
the breasts
- milk production and development of mammary glands
Where does GH stimulate
bone
HPG axis pathway ultimately produces what
testosterone and oestrogen
HPT axis controls what hormone
thyroid hormone
HPA axis controls what hormone
cortisol of adrenal cortex
masculinities the reproductive tract and external genitalia
promotes growth and maturation of reproductive system at puberty
spermatogenesis
develops sex drive
secondary sexual characteristics
are the functions of what hormone
Testosterone
what do leydig cells produce
testosterone
what do Sertoli cells stimulate from addition of testosterone
spermatogenesis
does puberty cause a positive or negative feedback to the hypothalamus/pituitary
positive
what cell secrets inhibin
sertoli cells
function of inhibin
controls production of FSH by Apituitary by negative feedback
what hormone stimulates leydig cells
LH
what stimulates Sertoli cells
FSH and testosterone
Does testosterone have a native feedback
yes - common feature of HPG glands
Mr Smith is suffering from hypogonadism (lack of production of testosterone) due to testicular dysfunction. His blood test shows lower testosterone levels than normal. What would you expect the levels of FSH and LH hormones to be in the blood sample?
Increased
what hormones do ovaries produce
oestrogen and progesterone
Maturation and maintenance of reproductive system
Female secondary sexual characteristics
Ova maturation and release
Transport of sperm to the site of fertilization
Preparing the uterus for developments o f embryo and foetus
Contributing to the breast ability to produce milk
function of what hormones
oestrogen and progesterone
Control metabolic rate
Increases heart rate
Needed for normal growth and development
function of what hormone
Thyroid
What does thyroid gland release
Triiodothyronine T3
Thyroxine T4
function of PTH
calcium metabolism - raises Ca2+
reduce urine loss
increase gut absorption
if circulating volume of BP to low what is released by kidneys
renin
what hormone is released to increase RBC production in bones during hypoxia
EPO
what are body sodium levels controlled by
Cortisol (promotes absorption)
what does the adrenal medulla release
Catecholamines such as adrenaline and noradrenaline
insulin function
secreted by B cells of langerhnads - reduce blood glucose
glucagon function
increase glucose conc
function of somatostatin
inhibits absorption of nutrients
Gherlin and Gastrin are hormones in the stomach what do they do
stimulate apetite
stimulate HCL production
Secretin and CCk in the small intestine do what
coordination of digestive functions
is adipose tissue and endocrine gland
yes
