All about the Hormones!
During fetal development and adolescence?
-Bone is initially formed in cartilage and collagen -Cartilage is calcified (becomes bone) -Bones grow as long as cartilage is made -Increase in tissue growth and organ growth is partic. evident in developing fetuses (IGF II)
What effect does ADH have on the Smooth Muscle (of arterioles)?
-Causes Vasoconstriction -This action is achieved at high [ ] of ADH and is mediated by V1 receptors
What exactly are Osmoreceptors?
-Cells in the hypothalamus sensitive to change in osmolarity
What effect does ADH have on the Sweat Glands?
-Decreases the number of surface sweat glands which leads to a decrease in water loss by perspiration (sweat less)
When does GHIH usually occur?
-During REM sleep -Dreams, 2 hours after onset of sleep -highers blood sugar
How do Somatostatins (GHIH) effect the feed back?
-Effect feedback on hypothalamus -increase somatostatin release which decreases GHRH release
What is the closure of epiphysis?
-End of growth when bone formation surpasses cartilage growth rate
Oxytocin receptors are increase by 2 other hormones, they are?
-Estrogen -Relaxin
How is Oxytocin involved with Child Birth?
-Estrogen hormone secretion induces an INCREASE in Oxytocin receptor in uterus -Oxytocin stimulates smooth muscle tissue contractions during labor
GHIH(Somatostatin) inhibits?
-GH release
High blood sugar causes? (in regards to GHIH)
-GHIH to increase
Low blood sugar/arginine being present causes?
-GHRH to increase -Deep sleep GHRH increase -REM sleep GHRH decrease
Growth Hormone Secretion is inhibited by?
-Growth Hormone Inhibiting Hormone (GHIH) -Also called Somatostatin (SS)
Growth Hormone Secretion is stimulated by?
-Growth Hormone Releasing Hormone (GHRH)
What is the JAK/STAT signaling pathway?
-Growth hormone interacts with membrane bound receptor -Activation of intracellular kinase (JAK) (Does not require a G-protein) -JAK phosphorylates STAT proteins(without G-protein involved)
Growth Hormones function is?
-HGH (human growth hormone) -In adults, produces muscle sparing energy source (without breaking down muscle) -In infants and during Puberty (a sky rocket amount)
How does Growth Hormone effect the feed back?
-Has effects in the hypothalamus -Increase GH release leads to decreased GHRH release -Increase GH release leads to increased somtatostatin (GHIH)
Where are the sleep centers? (Control systems for GH)
-Higher hypothalamus
Numerous inputs to where will control growth hormone release?
-Hypothalamus
Osmoreceptors activate?
-Hypothalamus signaling -Which causes Posterior Pituitary to release ADH
Where are the stress centers? (Control systems for GH)
-In the frontal lobe and high centers in the hypothalamus -These control reactions to stress
Where are Somatomedins produced?
-In the liver -Induced by Growth Hormone
What effect does ADH have on the Kidney?
-Increases water retention (takes H2O out of urine, back into body) -Decreases Urine production, Volume decrease -Increases Urine concentration -Functions through V2 receptors
The two forms of Somatomedins include?
-Insulin like growth factor I (IGF 1) -Insulin like growth factor II (IGF 2)
What is Prostagladins?
-Involved in initiation of birth/helps with contractions -Leads to bigger contractions
How is Oxytocin involved in Lactation?
-Is released during lactation to stimulate milk ejection
How is Oxytocin involved with the Uterus?
-It causes contraction of uterine smooth muscle during parturition (child birth) -There is a positive feedback -Contractions start slow and minor and increase in number and intensity during process
ADH targets what?
-Kidney (main target) -Sweat glands -Arteriole smooth muscle -Baroreceptors and stretch receptors (dilutes solutes out, brings H2O in)
The V2 receptor is associated with?
-Kidneys/ADH -V2 receptor is MORE sensitive to lower concentration activation
What are the chemical stimuli?(Control systems for GH)
-Low blood glucose -Act on the Hypothalamus (control GHRH release)
Once release, GH has targets in the?
-Muscle -Liver -Adipose tissue
What does Vasopressin cause?
-Osmotic pressure increases (less H2O) (a call for H2O to dilute contents aka too much solvents)
What are some of the characteristics of Growth Hormone?
-Peptide hormone (191 amino acids) -Major participant in control of growth and metabolism -Probably the MOST IMPORTANT HORMONE FOR GROWTH -Most abundant of the Anterior Pituitary
Some general characteristics of Oxytocin include?
-Peptide hormone (9 amino acids) -Differs from Vasopressin at position 8 (leu not arg) -Receptors are Trans-membrane G-Protein coupled
What is Ghrelin?
-Peptide hormone secreted from the stomach (prefix Ghre means grow)
Growth Hormone stimulates differentiation of?
-Phochondrocytes to Chondrocytes -An increase in chondrocytes leads to an increase in the effect of somatomedins (IGF I) which leads to an increase in linear long bone growth (Happens usually up to 20 years of age)
GHRH stimulates somatotrophs to produce what?
-Produce GH
Bones continue to grow until approximately...?
-Puberty to 20 years of age -The closure of epiphysis
Growth Hormone is also known as?
-Somatotropin or somatotropoic hormone (STH)
What are some other factors that are related to ADH effects?
-Stress (such as pain, emotions, nausea) [ cause to retain H2O] -These cause an increase in Vasopressin release -Ethanol (diuretic like effect) can cause a decrease in Vasopressin secretion (caffeine similar)
Growth Hormone Secretion is modulated by?
-Stress (such as) exercise -Nutrition -Deep Sleep -Growth Hormone itself
What exactly are Baroreceptors and their function?
-Stretch receptors in the HEART, ARTERIES, and Veins -Measure blood volume by stretch
When Blood volume increases (in relation to Baroreceptors)?
-The receptors stretch -Decrease in Vasopressin release -Pee a lot -Mainly through V1 receptor
An increase in Osmolarity stimulates?
-The receptors to activate neuroendocrine cells, leads to Vasopressin release -Blood volume decrease, which increase Vasopressin release
What are the secondary receptors of Oxytocin and what are they involved with?
-They use IP3 as a second messenger and opens Ca2+ channels
What are the major sites of action for Oxytocin in Women?
-Uterus--enhances contraction during deliver (positive feedback) -Breast--stimulated milk "letdown" following delivery (feed baby)
One example of an Anitdiuretic Hormone (ADH) is?
-Vasopressin
The V1 receptor is associated with?
-Vasopressor -V1 receptor is LESS sensitive to higher concentration activation
Vasopressor effect, Anti-diuretic action?
-Vasopressor effect- smooth muscle cells in arterioles -Anti-diuretic action- kidneys
What doe IGF I do?
-Works on chondrocytes (in children) -Increases bone linear growth
What does IGF II do?
-Works on the organs and tissues (as we grow older) -Increases tissue growth and increases organ size -Almost exclusively expressed in embryonic and neonatal tissues (growing pains = disproportionate growth)
What is the main function of Somatomedins?
-a group of hormones that is produced, when stimulated by somatotropin (STH), to promote cell growth and division. In this way, they mediate the effect of somatotropin (GH)
Stress causes GHRH to...which then causes GH release to....?
-causes GHRH to increase -causes GH release to increase
In adipose tissue what effect does GH have?
-decreased glucose uptake -increased lipolysis (break down of fat) -decreased fat stores
In the muscle what effects does GH have?
-increased amino acid uptake -decreased glucose uptake (keep as much glucose in blood stream as possible) -increased muscle mass
In the liver what effects does GH have?
-increased protein synthesis -increased RNA synthesis and gluconeogensis (making glucose from Carbon skeletons in liver) -Production of somatomedins (insulin-like growth factors that do GH's "dirty work"
Low blood sugar stimulates?
Stimulates GHRH
How is Oxytocin involved with the Breast Tissue?
-Acts on modified smooth muscle cells in the breast of females -Myopepithelial or ejection cells -Milk collects in the Lacififerous sinuses
What is the suggested activity of Oxytocin in Men?
-Appears to function in ejaculation -Functions in Leydig cells with spermatogenisis -Erection