endocrinology of growth Flashcards
what are the non-endocrine factors that regulate growth?
genetics is a principle factor
nutrition is critical
freedom from disease
what are the important growth-regulating endocrine factors?
hormones of the growth axis
thyroid hormones
glucose-regulating hormones
gonadal steroids
what are the 2 basic requirements for growth?
cell division/replication
protein synthesis
the final height of a human is determined by the growth of ___________
long bones
long bones grow as _____________ cartilage is replaced by bone
epiphyseal plate
cartilage replacement in long bones adds bone to which end of the diaphysis?
both ends
T/F: during the growth of long bones, the bone can make its own IGF-1
true
when do epiphyseal plates ossify?
during puberty
what are the two hypothalamic hormones that regulate GH secretion?
1) GHRH
2) somatostatin (SS)
what hypothalamic hormone decreases GH production? which increases it?
Decrease production- Somatostatin (SS)
increase production- GHRH
pituitary GH has what direct effects on somatic tissue?
1) stimulates protein synthesis
2) anti-insulin effects
Growth hormone (GH) will stimulate secretion of ______ from the liver and other tissues
IGF-1
T/F: feedback regulation of GH secretion is both long-loop and short-loop negative feedback
true
IGF-1 will ________ the secretion of GH & GHRH
decrease
what hormone will be increased when IGF-1 levels rise?
SS (somatostatin)
both GHRH and SS exhibit what patterns of secretion?
contrasting diurnal patterns
GHRH stimulated during early sleep, SS stimulated more during the day
both _____ and _____ (hormones) are needed for proper growth
GH and IGF-1
_______ growth is the result of interactions between GH and IGF-1
somatic
what can cause deficiencies in GH and IGF-1
1) genetic mutations (but NOT for IGF-1, or fetus would die)
2) deficits caused by malnutrition
how does GH production change with age?
high during adolescence
lowest during adulthood
what type of hormone can regulate the production of GH?
sex steroids- particularly Androgens
estradiol & testosterone
how do androgens stimulate GH synthesis? IGF-1 synthesis?
Stimulate GH by increasing GHRH secretion
Stimulate IGF-1 directly
__________, a sex hormone, will stimulate the ossification & fusion of epiphyseal bone plates
estradiol
T/F: cortisol/glucocorticiods have anti-growth effects
true
cortisol will inhibit _______ and ______ secretion
GHRH and GH
excess production of GH results in ________ and _______
acromegaly and gigantism
gigantism results from ___________ onset of excess GH
prepubertal
what does acromegaly result from?
postpubertal onset of excess GH
_________ is also known as “GH insensitivity”
dwarfism
what occurs during dwarfism?
no IGF-1 synthesis
they still have IGF-2, or else they would die
what causes achondroplasia?
fibroblast growth factor receptor is constitutively active
_________ will result in abnormal cartilage formation
achondroplasia
symptoms of people taking growth hormone will resemble _________
acromegaly
what are the symptoms of acromegaly?
- no increase in height
- bones increase in thickness
- muscle size increases (hypertrophy of heart)
- increase blood glucose and fatty acids
what causes diabetes?
a disruption in the normal function of insulin
insulin is a _______ hormone produced by the pancreas
peptide
loss of insulin function can lead to __________, and can be fatal
ketoacidosis
what are the symptoms ketoacidosis?
- increased ketones in blood
- increase in kidney filtration
type 2 diabetes is a combination of what?
insulin resistance & insulin deficiency
common symptoms of diabetes relate to increases in ________________
circulating glucose
chronic hyperglycemia leads to what common complications of diabetes?
1) kidney failure
2) vascular disease
3) blindness
4) skin & mucosal infections
5) periodontal disease
how is diabetes a problem for dental providers?
- decreases blood flow
- dehydration
- increase risk of periodontal disease
