ADH, oxytocin, and GH HW Questions Flashcards
Which hormones are secreted by the posterior pituitary?
ADH and oxytocin
ADH and oxytocin are secreted by unmyelinated C fibers of __________________ neurons from the paraventricular and supraoptic nuclei of the hypothalamus
magnocellular
Baroreceptors send signals to inhibit ADH secretion through the vagus and glossopharyngeal nerves to the medulla oblongata, from there signals are carried to the hypothalamus through the __________________
tractus solitarius
Which type of neuron fibers forms the hypothalamic hypophyseal tract from the hypothalamus through the infundibulum to the posterior pituitary?
Unmyelinated C
Which hormone classification are the hormones secreted by the posterior pituitary?
Polypeptide
ADH utilizes the _________ second messenger system to stimulate kidney tubule epithelial cells whereas vasopressin uses the ____________________ second messenger system to stimulate arteriole smooth muscle
cAMP, phospholipase C
Which hormone causes kidneys to reabsorb water from collecting ducts?
ADH
How does vasopressin affect blood vessels?
Vasoconstriction
ADH will _____________ ECF while vasopressin will ___________ blood pressure
Increase, increase
___________________ in the hypothalamus monitor the concentration of blood plasma
Osmoreceptors
Which hormone is secreted when solute concentration of blood plasma is high and/or blood volume is low?
ADH
What hormone stimulates thirst?
Ang II
What conditions cause atrial stretch receptors to signal the hypothalamus to secrete ADH?
Lack of stretch
What conditions cause the aortic and carotid baroreceptors to inhibit ADH secretion?
Excited by high pressure
How does the lack of ADH affect the kidneys?
Reduced ability to reabsorb water
How does lack of ADH affect urine concentration?
Diluted
What happens to body fluids when there is a lack of ADH?
Decrease in volume
Why does a lack of or resistance to ADH cause a headache?
Brain cells shrink
What condition is due to hyposecretion of ADH or insensitivity of ADH receptors?
Diabetes insipidus
How does oxytocin affect the pregnant uterus?
Stimulates contractions
What action stimulates the release of oxytocin during labor?
Distension of cervix
What action stimulates the release of oxytocin during breast feeding?
Suckling of nipples
How are levels of oxytocin regulated?
Positive feedback
What is the role of oxytocin in lactation?
Causes milk ejection
The major target tissues of GH are….
bone and skeletal muscle
The HPA for GH is the hypothalamus secretes _________ which stimulates the anterior pituitary to secrete ________ which binds to almost all body cells to stimulate growth
GHRH, GH
When does the body stop producing GH?
Never
Growth hormone increases serum glucose by inhibiting GLUT4 receptors and stimulating liver ____________________
Gluconeogenesis
GH can stimulate bone to grow in…..
Length and width
What is the circadian rhythm of GH?
First 2 hours of deep sleep
What healthy activity can stimulate GH secretion?
Strenuous exercise
Under acute conditions, what is the strongest stimulus of GH secretion?
Hypoglycemia
Under chronic conditions, what is the strongest stimulus of GH secretion?
Dietary protein deficiency
What is the main physiological process GH stimulates in most tissues?
Increases rate of protein synthesis
How does GH increase protein synthesis?
Promotes cellular uptake of AAs
What effect does GH have on ribosomes?
Increases number and activity
Why is GH called a protein sparer?
It decreases proteolysis
How does GH indirectly increase serum insulin?
By increasing serum glucose
Why is GH’s effect of stimulating liver gluconeogenesis short lived?
Because insulin inhibits liver gluconeogenesis
How does insulin affect plasma AAs?
Promotes cellular uptake of AAs
GH is a diabetogenic hormone because overproduction can cause
Pituitary diabetes
What effect does GH have on fat metabolism?
Stimulates mobilization of FAs and limits storage
How does excessive GH secretion lead to ketosis?
Too much acetoacetic acid produced
How does GH stimulate bone growth?
Stimulates osteoblast activity
What small protein does GH stimulate the liver to produce that has properties similar to insulin?
Insulin like growth factors (IGF1)
What effect does IGF1 have on tissues?
Stimulates protein synthesis and bone growth
Which congenital condition results from panhypopituitarism?
Dwarfism
Approx 1/3 of Dwarfs experience puberty because they only lack…..
Growth hormone
Which condition is a result of over production of GH before growth plates close?
Gigantism
What can cause gigantism and or acromegaly?
Anterior pituitary tumor
Which condition is a result of overproduction of GH after growth plates close?
Acromegaly
