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.
General affects of T3 and T4
increase protein synthesis by increasing transcription of many genes for enzymes, structural proteins, transport proteins, and other substances
increase functional activity of proteins throughout body
Thyroid hormones’ effects on Metabolism
60-100% increase in basal metabolic rate (BMR)
increase number and activity of mitochondria
increase rate of active transport of ions through cell membranes; esp. Na+/K+ pump
Thyroid hormone effect on growth
in humans, main effects are on growing children
hypothyroid means rate of growth is slow
hyperthyroid means rate of growth is accelerated so child is tall, but the epiphyseal plates on the long bones may fuseprematurely to cause a short adult
important effects on growth and development of CNS during fetal life and 1st few years of childhood
low levels during pregnancy and childhood can result in permanent mental retardation
Special effects of thyroid hormones
increase carbohydrate metabolism increase CHO utilization increase rapid uptake of glucose by cells increase glycolysis increase gluconeogenesis increase absorption from SI increase insulin secretion
Thyroid hormone effects on Fat metabolism
increase fat utilization
lipids are mobilized from adipocytes
increased thyroid hormone causes a decrease in cholesterol, phospholipids, triglycerides in plasma and an increase in free fatty acids in plasma
hypothyroidism: if chronic, often results in atherosclerosis due to increase plasma cholesterol levels and a fatty liver
Thyroid hormone effects on Vitamins
an increase in thyroid hormone causes an increase in the need for coenzymes, so causes a need for an increase in vitamins in diet because vitamins are needed to make coenzymes
Thyroid hormone effects on body mass
increase in thyroid action causes a decrease in body mass and vice versa, but an increase in thyroid hormone also increases appetite which partly counters the effect
Hyperthyroidism effects on the CNS
nervousness, psychoneuroticism, anxiety, worry, and
paranoia
Hypothyroidism effects on the CNS
mental sluggishness and apathy
Thyroid hormone effects on muscles
Hyperthyroidism can lead to fine muscle tremors and
hypothyroidism can lead to sluggish muscles with slow relaxation.
Thyroid hormone effects on sleep
Hyperthyroidism can lead to difficulty sleeping but with a feeling of always being tired. Hypothyroidism can lead to extremesomnolence with sleeping occurring 12-14 hours per day
An increase in T3 and T4 causes
A decrease in TSH secretion (Negative feedback)
Symptoms of hyperthyroidism
high state of excitability, intolerance to heat, increased sweating. mild to extreme weight loss, diarrhea, muscle weakness, nervousness or other pyschic disorders, fatigue but can’t sleep, hand tremors exopthalmus (bug-eyes) can cause optic nerve or corneal damage
Hypothyroidism
probably also an autoimuune disease
gland is destroyed which results in a great reduction of T3 and T4
other types can cause a wildly enlarge thyroid gland (goiter)
Cretinism
Extreme hypothyroidism during fetal stage, infancy, or childhood leads to stunted growth and mental retardation.
Unless treated early, the effects are permanent.
3 families of corticosteroids
Mineralcorticoids
Glucocorticoids
Sex hormones
Mineralcorticoids
get their name because they affect the minerals (K
+, Na+) in the body; aldosterone is of principal importance
Glucocorticoids
get their name because they affect blood glucose concentrations; cortisol is of principal importance
Sex hormones
esp. androgens; not very important unless secreted in excess, then masculinizing
Layers of the Adrenal Cortex
Zona glomerulosa
Zona Fasciulata
Zona Reticularis
Zona glomerulosa
most superficial; thin; 15% of adrenal cortex; secretes aldosterone, angiotensin II and other mineralocorticoids
Zona Fasciulata
middle layer; wide; 75% of adrenal cortex; secretes cortisol, other glucocorticoids, and small amounts of
androgens and estrogens; controlled by hypothalamus/AP via ACTH
Zona Reticularis
deep layer; 10% of adrenal cortex; secretes androgens, estrogens, some glucocorticoids; regulation is poorly
understood
Results of loss of mineralcorticoids
hyperkalemia in ECF
NaCl depletion from body
blood volume and ECF depletion
decrease in CO and cardiac failure
Function of Glucocorticoids
95% of glucocorticoid action is due to cortisol (hydrocortisone) which affects carbohydrate, protein, and fat metabolism
Effects of glucocorticoids on metabolism
stimulates gluconeogenesis by liver with a 6-10X increase due to: increased DNA transcription of enzymes that can convert
amino acids to glucose and mobilization of amino acids from muscle decreases glucose use by cells with a moderate effect
both gluconeogenesis and decrease in glucose use cause an increase in plasma glucose levels, but insulin is not as effective asnormal in controlling blood glucose levels so the result is a 50% increase in plasma glucose levels in a condition called adrenal diabetes
5 Stages of inflammation
- stressed tissue releases chemicals that activate the inflammation process (histamine, bradykinin, proteolytic enzymes,prostaglandins, leukotrines)
- increased blood flow to stressed area = erythema
- leakage of plasma out of blood into ISF due to increase in capillary permeability which results in edema
- WBCs infiltrate area
- fibrous tissue growth in area at later date
4 cell types in the islets of Lanerghans
- alpha: 25%; secrete glucagon
- beta: 60%; middle of islet; secrete insulin and amylin
- delta: 10%; secrete somatostatin
- PP: 5%; secrete pancreatic polypeptide
Islet cell communication and control
The close proximity of these cells allows direct cell to cell communication and mutual control:
- insulin inhibits glucagon
- amylin inhibits insulin
- somatostatin inhibits insulin and glucagon
