Final Review Flashcards
Growth Hormone increases protein synthesis by
increase amino acid transport into cells
increase rate of RNA translation
increase rate of DNA transcription
decrease catabolism of proteins/amino acids
Growth Hormone increases fat utilization by
increase release of fatty acids from adipose tissue
increase conversion of fatty acids to acetyl -CoA
Growth hormone decreases carbohydrate utilization by
decrease glucose uptake by tissues
increase glucose production by liver
increase insulin production
GH increases skeletal growth by
ncreased deposition of protein by the chondrocytic and osteogenic cells that cause bone growth
increased mitosis in chondrocytes and osteocytes
trigger conversion of chondrocytes into osteocytes
How does bone growth occur (in regards to GH)
Bone growth occurs with an increase in GH by an elongation of the bone and an increase in thickness of the bone.
Elongation of thebone occurs at the epiphyseal plates of the bone through a deposition of cartilage and the conversion of that cartilage into new bone until the cartilage is used up which typically occurs at the end of adolescence.
GH also stimulates osteoblasts to deposit bone faster
than osteoclasts remove old bone which increases the thickness of the bone.
GH can cause thickening of the bone especially in the
jaw and skull even after adolescence.
Factors that affect GH
Age Starvation Deep Sleep Strenuous exercise Excitement, stress, trauma Blood chemicals Obesity
Normal levels of GH for each age group
5-20 years old: 6 ng/ml
20-40 years old: 3 ng/ml
40-70 years old: 1.6 ng/ml
GH therapy in old people may retard aging by
increasing protein synthesis
decreasing fat deposition
increasing energy levels
panhypopituitarism:
results from decreased secretion of all AP hormones either congenital or from a tumor that destroys AP
pituitary dwarfism:
A generalized deficiency of AP hormones during childhood causes all parts of the body to develop in the
correct proportion but at a reduced rate. A 10 year old with this disease may have the body of a 4-5 year old and a 20 year oldmay have the body of a 7-10 year old. Most people with this disease never pass through puberty because they never secreteenough LH and FSH, so have no adult sexual function. However 1/3 of people with this condition have only reduced GH
secretion, so they have normal sexual function. Treatment of this condition with synthetically produced GH grown by E. coli thathave undergone recombinant DNA processes can be completely successful in generating a cure if the it is given in childhoodand the only problem is a deficiency in GH production
panhypopituitarism in adults
can be caused by tumors that destroy the anterior pituitary or thrombosis of anterior pituitary blood
vessels. The effects can include hypothyroidism which results in lethargy, depressed glucocorticoid production that can lead toobesity, and suppressed secretion of gonadotropic hormones which can lead to loss of sexual function
gigantism
GH producing cells become extremely active often because of a tumor or a large increase in GH. If this occurs beforepuberty, the person becomes a giant (8 ft) with symptoms of hyperglycemia that may lead to diabetes mellitus in 10% of cases.
acromegaly
A tumor in the GH producing cells occurs after puberty so a person cannot get taller, but his bones and soft tissuescan get bigger. Often the jaw protrudes, forehead slants, nose gets 2X bigger, feet and hands grow, back hunches (kyphosis), and soft tissues and organs get larger
ADH Function
increases the permeability of the collecting ducts in the kidneys to water to increase water reabsorption to make a more concentrated urine
Mechanism of ADH
ADH binds to receptors activates adenylyl cyclase to form cAMP which phosphorylates elements in special vesicles that contain aquaporins vesicles fuse to cell membrane and aquaporins form pores
3 functions of oxytocin
During labor, it is released during smooth muscle contraction to amplify the contractions
Aids in milk ejection
Released during sexual intercorse
Role of oxytocin in milk ejection
stimulus: sucking on nipple
sends a signal to the paraventricular and supraoptic nuclei of hypothalamus
results in the release of oxytocin from posterior pituitary
oxytocin causes contraction of myoepithelial cells which allows milk to be ejected or “let-down”
Role of oxytocin in copulation
Sexual intercorse causes oxytocin to be released and peaks with orgasm
psychic stimuli involving the amygdala
the resulting contractions in the smooth muscle of the uterus increase the number and rate of sperm transport toward the egg which increases the probability of fertilization
How do oxytocin and prolactin work together to produce milk
Oxytocin and prolactin are a team. Oxytocin triggers
milk let-down and prolactin triggers milk production.
