chpt 6: Flashcards
what type of hormone is insulin
hydrophilic
large peptides like catecholamines (NE and E) are
hydrophilic
what secrets catecholamines (NE and E)
adrenal medulla
catecholamines (NE and E) are derived from
tyrosine (no iodine)
estrogen is an example of
steroid hormones
steroid hormones come from
cholesterol
the function of adrenal glands with steroid hormones
modify and turn them into sex hormones
examples of lipophilic hormones
- steroid hormones
- thyroid hormones
how are thyroid hormones formed
from tyrosine (iodinated)
what gland is a true endocrine gland
- thyroid gland
- adrenal cortex
the function of the thyroid gland
modifies tyrosine to form thyroid hormones
what is the method of circulation for hydrophilic hormones
50% free in the blood
50% bind to plasma proteins
what hormones binds to receptors ON plasma mem
hydrophilic
what mechanisms of actions of hydrophilic hormones
- cAMP 2nd messenger sys
- Ca 2nd messenger sys
where is the receptor for lipid hormones
- in nuclei on DNA (HRE)
how do lipid hormones cause change
alter gene to produce new intracellular proteins
what type of hormones circulate bound to plasma proteins
lipophilic
which ANS is cAMP relevant
sympathetic system
the function of cAMP in the mechanism of action of hydrophilic hormones
- amplify response
- activate PKA
what converts atp to cAMP of cAMP in the mechanism of action of hydrophilic hormones
adenyly cyclase
function of G protein in cAMP in the mechanism of action of hydrophilic hormones
excite adenylyl cycylase
what modifies/ uses ATP to cause cellular change / response in AMP in the mechanism of action of hydrophilic hormones
PKA
overall function of cAMP in the mechanism of action of hydrophilic hormones
-alters the activity of intracellular proteins to produce desired effect
- change cell permeability
function of g protein in Ca 2nd messenger sys
activates phospholipase C
what breaks down PTP2 into IP3 and DAG
phospholipase C
function of IP3
- moblize Ca that came from the ER, all over cell
what breaks down ATP in the IP3 2nd messanger sys
CaM kinase which was activated by Ca+ calmodulin
function of DAG
- activates PKC which breaks down ATP to activate inactivated protein and produce cell response
does the endocrine sys regulate RBC production
yes
tropic hormones function
regulate hormone secretion by other endocrine glands
example of tropic hormone
TSH
FSH and LH
ACTH
Prolactin
MSH
GH
function of TSH
- stimulates thyroid hormone secretion by thyroid
- maintain structural integrity of thyroid
which hormones does the thyroid gland prdocue
- thyroxine
- triiodothyronine
- calcitonin
which hormone is secrete by the stomach, hypothalamus and pancreas
somatosin
what hormone targets more than 1 tissue
oxytocin
when does the rate of secretion of a hormone vary
during menstrual cycle
what is so special about hepatocytes
they respond to more than 1 hormone; insulin and glucagon
which chemical messanger is capable of being a neurotransmitter and a hormone
NE
pancreas and gonads share what in common
they are endocrine organs that are not exclusively endocrine in function
what is the plasma concentration of each hormone controlled by
regulating rate of hormone secretion
factors influencing secretory output from another hormone
- neural input and input from another hormone
- rate of removal from blood by metabolic inactivation and excretion from urine
- rate of metabolic activation or its extent of hormone binding to plasma proteins
- rate of secretion into blood by gland
- feedback main function
maintain the plasma concentration of a hormone at a given level
when is an action of hormone cause further release of hormones
+ fb system
neuroendocrine reflex function
- produce a sudden increase in hormone secretion in response to a specific stimulus
- when the hormone is in immediate need
do alterations in transport, metabolism and excretion influence hormone plasma concentrations
yes
how are hormones and their metabolic wastes removed from blood
by urination
how does the hormone plasma concentration decrease
transported out of blood
what determines how long hormones are active for
- access to enzymes
- enzyme acitvity
what do endocrine disorders result from
abnormal plasma concentration of a hormone caused by inappropriate rates of secretions
cause of primary hyposecretion
gland abnormality caused by:
- genetic
- dietary
- chemical/ toxic
- immunological
- cancer
- iatrogenic or idiopathic
gland is working but there is a deficiency in tropic hormones so there decreased hormones secretion =
secondary hyposecretion
when does a tumour secerte too much hormone
primary hypersecretion
secondary hypersecretion is
excessive stimulation from outside the gland causes oversecertion
example of when the target cells arent responding
diabetes
possible causes of abnormal target cell responsiveness
- lack of receptors for the hormone
- lack of enzyme essential for carrying out response
is the number of receptors constant
no
what affects signal magnitude transmitted across cell membrane
the varied number of receptors
what is an example of fine tuning
- down - regulation of insulin receptors
- deliberate alterations of receptors
what happens with down regulation of insulin receptors
- number of insulin receptros on lover cells is reduced in the precense of increase concentration of plasma insulin
what prevents over rxn of target cells to insulin and effects blunt effects of insulin hyper
down - regulation of insulin receptors
what is it called when one hormone must be present in adequate amounts for full exertion of another hormones effect
permissive
example of permissvie hormone action
thyroid hormone increase number of E receptros on target cells
synergism function
occurs when actions of several hormones are complementory
growth hormone and food
fsh and testostrone
are examples of
synergism
what occurs when one. hormone causes loss of another hormones receptors and redeuces the effectiveness of 2 nd homornes
antagonism
example of antagonism
- insulin and glucagon
- calcitonin and parathyroid hormones
what controls the secretions of the pg
hypothalamus
what makes up the neuroendocrine system
hypothalamus and posterior pg
posterior pg is aka
neurohypophysis
how is the ppg connected tp the hypothalamus
by neural pathways
which pg stores and releases hormones synthesized by the hypothalamus
ppg
which hormone is responsible for conserving water by vasoconstriction/ increase BP and increase reabsorption of water
- vasopressin
examples of hydrophilic ppg hormones
- vasopressin
- oxytocin
function of oxytocin
- contract uterus during childbirth
- milk ejection
- bonding with infant
adenohypohysi is
apg
what is apg made of
glandular ep
how is the anterior pg connected to hypothalamus
- vascular pathways (portal sys)
anterior pg function
synthesize and release hormones
which tropic hormones does the apg release
- GH
- TSH
- FSH
- LH
- ACTH
- PRL
growth hormone (GH) function
- regulating overall growth
- protein anabolism
- glucose conversion
- fat mobilization
which apg hormone is responsible for:
- stimulating cortisol secretion
- growth of adrenal cortex
adrenocorticopic hormone- ACTH
growth hormones function
- stimulate growth of bones
- protein anabolism
- fat mobilization
- glucose conservation
what hormone promotes follicular growth and development and stimulates estrogen and progesterone secretion in females
FSH
function of FSH in males
stimulate seminiferous tubules in testes to produce sperm
function of LH in females
- stimulate ovulation, corpus luteum development
- secrete estrogen and progesterone
what hormone targets interstitial cells of leydig in testes to stimulate testosterone
LH in males
function of prolactin in males
uncertain
how does the hypothalamus regulate apg hormones secretion
- hypothalamic hypophysiotropic hormone
what sets to hierarchic chain of command
hypothalamic hypophysiotropic hormone
example of apg hormone that is secreted by more than 2 hormone
GHRH and GHIH
what is the first hormone in the hierarchic chain of command and its function
hypothalamic hypophysiotropic hormone, which stimulates apg hormone
apg is which hormone in the hierarchic chain of command and its function
second, function is to stimulate target gland/ cell
what controls the hypothalamus
- NS/ brain
function of portal sys
link between NS and endocrine system
how does communication occur via the portal sys
blood flow from one capillary bed to another
which glands make up the hypothalamic-hypophyseal porta system
apg and hypothalamus
does most of the apg blood pass through hypothalamus first
yes
which portal system is the largest and the best
hepatic portal sys
growth =
- lengthening of long bones
- increase in size and number of cells in soft tissue
what does growth depend on
- genetic determination of an individuals max growth capacity
- adequate diet
- excess food intake
- chronic disease and stressful environment
function of macromolecules
- building blocks for protein
what type of food is used for functioning of enzymes
micromolcules
which hormone can be anti growth
cortisol
cortisol x growth
enhances protein breakdown, inhibit growth of long bones, and blocks GH secretion
if stressful conditions are reversed during growth, can one catch up
yes
which hormones influence growth hormone secretion and growth
- thyroid hormones
- sex hormones
- insulin
is the rate of growth continuous
no
what hormone prevents apoptosis
GH
metabolic changes caused by GH
- increase rate of protein synthesis
- increase fatty acid mobilization and E use
- decrease rate of glucose use
types of different growths
- fetal growth
- post-natal growth
- pubertal growth spurt
what promotes fetal growth
hormones from the placenta
when does GH play no role in development
fetal development
when does post-natal growth occur
- after birth
- non placenta GH help
what type of growth is marked by lengthening of long bones and occurs during the first few years of life
post-natal growth
what contributes to growth spurt in pubertal growth spurt
sex hormones and GH
androgen function
male sex hormones that increases testosterone in boys, protein synthesis and bone growth
what halts bone growth at the end of adolescence
testostrone and estrogen
increase in the number of cells is known as
hyperplasia
hypertrophy is
increase in size of cells
bone formation is known as
ossficiation
what hormone directly affects bone formation
GH
how is bone thickness achieved
- osteoblasts adding news bone cells to outer surface of existing bone
function of osteoclasts
- bone breakers
- dissolve away inner surface of bone
how does bone length occur
cartilage adding on the epiphyseal plate
- proliferation of chondrocytes on the outer edge of the epiphyseal platte
what happens when the epiphyseal plate is formed
bone doesnt increase in lenght
insulin like growth factor is aka
somatomedin
how is somatomedins secreted from the liver
UPON stimulation from growth hormone
which IGF is more important
IGF-1
how does IGF-1 influence other hormones
paracrine
function of IGF-1
- acts directly on bone and soft tissues to bring about most growth- promoting actions
- stimulates protein synthesis, cell divison, lengthening and thickening of bones
what does the production of IGF-1 depend on
- nutrion
- age
what does a decrease in food mean more IGF-1
it decreases
increase GH which increases IGF-1 at puberty is
an age related production factor for IGF-1
what type of IGF has an unclear role in childhood and adulthood but important during fetal development
IGF-2
is the production of iIGF-2 influenced by GH
no
what factors influence GH secretion
- hypothalamus secreting 2 antagonistic hormones
- diurnal rhythms
- exercise, stress and hypoglycaemia
- homeostasis of blood levels of glucose, a.a, f.a
what causes inhibition of GH from apg
- GH
- somatomedin
- GHIH
GHIH is aka
somatostatin
what hormone may inhibit GHRH
somatomedin
when does GH increase in a day
first few hours of sleep
GH levels during the day
Low and constant
what hormone increases when E demands are largeer than
GH
decreased fatty acids =
increaser GH secertion
increased a.a after a protein meal =
increased GH secertion
why does growth hormone deficiency occur
- due to pg defect or hypothalamic dysfunction
how are symptoms in adults with GH deficiency
few symptoms
hyposecretion of GH in children is known as
- dwawrfisim
primary cause of dwarfisim
- lack of GH from apg
lack of GHRH stimulating the apg is
the secondary cause of dwarfisim
lack of GHRH stimulating the apg is
the secondary cause of dwarfism
symptoms of dwarfism
- short cuz of retarded sk growth
- poorly developed muscles
- excess fat due to decreased fat moblization
larson dwarfism is
- failure of tissues to respond to GH
- GH insenstiivty
IN ADULTS
- reduced sk muscle mass
- decreased bone density
- risk of developing heart failure
larson dwarfism
tumour of GH- producing cells of apg is
growth hormone excess
when do symptoms of a disorder depend age of individual when abnormal secretions begins
during growth hormone excess
overproduction of GH in childhood b/f epiphyseal plate closes is known as
gigantism
acromegaly occurs
when GH hyper-secretion occur after adolensce and the closure of epiphyseal plate
symptoms of growth hormone excess
- thickening of soft tissues, bones, extremities and face
- peripheral nerve disorder may occur as nerves may be trapped
which hormone is needed for growth but doesnt promote it
thyroid
does hypersecretion of the thyroid = increased growth
no
which hormone is needed for skeletal growth
thyroid
what happens to a child with hypothyroidism
stunted growth
what happens with too much insulin and growth
- excessive growth
function of adrogens in pubertal growth
- promote protein synthesis
- linear growth
- gain in body weight
- muscle mass
what stimulates complete conversion of epiphyseal plate
estrogen
what gland secrete melatonin
pineal gland
what controls the biological rhythm (wakefullness, temp regulation and gene expression)
suprachiasmamtic nuclue (SCN)
what do the self-starting genes of SCN produce
clock protiens
function of clock protiens
- cyclic changes in neural discharge from SCN
- linked to circadian rhythms
what kind of mechanism does the night-day cycle use
inhibitory feedback
what causes the synthesis of PER proteins
- active gene period
what accumulates in the cytoplasm during the day
PER proteins
when is PER gene active
when clock proteins degrade and remove their inhibitory effect
how many days does it take fix jet lag
3-5
how does SCN sync with environment
- works with pineal gland and melatonin
- eye contains melanopsin (detects light send signals to SCN to pineal gland, which releases melatonin)
melatonin function
-reproduction and onset of puberty
- promote sleep
- slow aging
- enhances immunity
- acts as antioxidants to remove free radicals (cancer)
- sync body with environment
- birth control
how does melatonin act as birth control
inhibtis ovulation
decreased in melatonin means
onset of puberty
how does melatonin enhance immunity
reverses aging of thymus
